Key Factors for the Separation of Silicon and Iron during Phosphorus Recovery from Slag Discharged from the Double-Slag Refining Process

In the present study, we developed a technology for concentrating and recovering phosphorus from slag-like phosphorus-containing unused resources and applied it to slag discharged during the latest steelmaking process, that is, double-slag refining process (DRP). The technology we developed consists of the following four processes: Process (1) is the initial acid elution; Process (2) involves alkali precipitation; Process (3) is the second acid elution; and, Process (4) utilizes ion-exchange. In Process (1), the addition of DPR slag to 0.5 M of a nitric acid solution for 24 min resulted in sufficient phosphorus dissolution. In Process (2), ammonia was added to the dissolved solution, and phosphorus was precipitated with high efficiency. The timing of the addition of ammonia significantly influenced the removal of silicon and iron, which would have been inconvenient to accomplish in subsequent processes. In Process (3), the precipitation obtained in Process (2) was re-dissolved in a nitric acid solution. The dissolution of phosphorus together with other elements progressed sufficiently, and we confirmed that silicon could be completely separated as silica by using high-concentration nitric acid at this stage. The fact that silicon could be removed during Process (3) was an important finding, since silicon could not have been separated in the Process (4). In Process (4), by passing the phosphorus-containing solution obtained in Process (3) through an ion exchange resin, elements other than phosphorus and silicon could be removed, which confirms that the range of applications for this technology could be expanded.


Regeneration of Alumina-Supported Nickel Oxide Catalyst Covered with Large Amounts of Carbon Deposits During the Dehydrogenations of Ethane, Propane, and Isobutane

Improvement in the dehydrogenations of ethane, propane, and isobutane over alumina-supported nickel oxides have been reported along with the formation of large amounts of carbon deposition with time-on-stream, but catalyst activity is decreased with an additional increase in time-on-stream. This improvement in activity is due to metallic nickel that is highly dispersed over carbon nanotube-like depositions. When this highly dispersed metallic nickel is further covered with carbon deposits, the activity decreases. In this paper, we describe the result of oxygen treatment to regenerate the catalyst. It is generally accepted that oxygen treatment, to remove carbon depositions, results in a less active catalyst due to sintering of the active species. We speculated, however, that sintered nickel oxide could form carbon nanotubes in the proposed system, and that the formation of highly dispersed nickel over the nanotubes would regenerate the catalyst. To prove this hypothesis, the dehydrogenations of ethane, propane, and isobutane were investigated using 18, 15, and 20% nickel oxide supported on γ-alumina, respectively. We confirmed regeneration of the catalytic activity via oxygen treatment during subsequent dehydrogenations.

アルミナ担持酸化ニッケル触媒によるエタン，プロパン，およびイソブタンの脱水素化では，通塔時間に伴う炭素析出の形成とともに，触媒活性の向上が観察されることが報告されている．この改善挙動はカーボンナノチューブ状析出物上に高分散状態で形成される金属ニッケルに起因されるが，さらに通塔時間を長くすると，カーボンナノチューブ状析出物が通常の炭素析出物によって覆われ，活性が低下する． 本稿では，活性が低下したアルミナ担持酸化ニッケルを酸素処理により再生した結果について述べた． 炭素堆積物を除去するために酸素処理を用いると，活性種のシンタリングより，触媒活性成分が低分散化され，活性が低下することが一般に知られている． しかしながら，本触媒系では，酸素処理でシンタリングした低分散の酸化ニッケルが形成されたとしても，再度接触反応に用いると，そこからカーボンナノチューブが形成され，このナノチューブ上に高分散状態で金属ニッケルが形成され，良好な触媒活性が再生されることが期待される．この仮説を証明するために，エタン，プロパン，およびイソブタンの脱水素化を， -アルミナに酸化ニッケルを 18%，15%，および 20%担持した触媒を用いて検討した．その結果，これら3種類のアルカンの脱水素に対して，本稿で提案した酸素処理による触媒活性の再生が良好に行われることが明らかになった．

Journal of the Japan Petroleum Institute


Effective Dechlorination of 2-Chloropropene to Propylene on a Metallic Nickel Catalyst Supported on γ-Alumina

In our previous paper, we reported that the reductive conversion of 2-chloropropene (2-PEN) on -alumina-supported palladium catalysts showed high activity at 348 K. In this catalyst system, however, 2-chloropropane (2-PAN), propylene, and propane were produced non-selectively, which necessitated a separation process when considering actual industrial development. In the present study, an alumina-supported nickel catalyst achieved a highly selective conversion of 2-PEN to propylene. For example, at 473 K, the propylene selectivity reached 95.7% when the conversion of 2-PEN was 15.0% on the catalyst loaded with 10% nickel. However, since propylene yield was only 14.3%, the reaction was examined at 623K. This resulted in a 75.6% conversion of 2-PEN and a 78.6% selectivity to propylene, which accompanied to a sufficient 59.4% yield. The most notable point was that no propane was produced under these conditions. Therefore, there is no need to separate propane and propylene. We concluded that by using nickel as a catalyst, an excessive reduction of propylene to propane could be suppressed.

前報では，アルミナ担持パラジウム触媒による 2-クロロプロペン (2-PEN) の接触還元が 348 K で高い活性を示したことを報告した．しかしこの場合，2-クロロプロパン(2-PAN)，プロピレンおよびプロパンが非選択的に生成されたので，実際の社会実装を考えると分離プロセス併設が不可欠となっていた． 本研究では，アルミナ担持ニッケル触媒が 2-PEN のプロピレンへの高選択的変換を達成できることを明らかにした． たとえば，473 K では，10% の Ni を担持した触媒を用いると， 2-PEN の転化率が 15.0%，プロピレンの収率は 95.7% に達した． 但し，プロピレン収率が14.3%であったため，623Kで反応を検討した． その結果，2-PENの転化率75.6%，プロピレンへの選択率78.6%となり，プロピレン収率が59.4%となった． 最も注目すべき点は，この条件下でプロパンが生成されなかったことである． したがって，本触媒系では，プロパンとプロピレンを分離する必要はない． ニッケルを触媒として用いることで，プロピレンからプロパンへの過度の還元が抑制されると結論付けられた．


Phosphorus Recovery from Sewage-sludge Molten Slag Using a Combination of Acid-dissolution, Alkali-precipitation, and Ion-exchange

We recently reported an efficient procedure for recovering phosphoric acid from dephosphorization slag. This recovery procedure consists of a combination of the following four processes: (1) A first dissolution process of slag in a nitric acid solution; (2) a precipitation process then adds ammonia to the obtained eluate; (3) a second dissolution process dissolves the precipitation from the nitric acid eluate; and, (4) the final process involves ion exchange in which the obtained eluate is passed through an ion exchange resin. In the present study, this recovery procedure was applied to concentrate and recover phosphorus from sewage-sludge molten slag, which is an unused resource that should be considered a new resource for phosphorus. As a result, our procedure for recovery from dephosphorization slag was viable following two revisions. Initially, the time for the first dissolution process was extended from 0.2 h to 1 h, but 0.2 h proved to be the optimum time for dephosphorization slag. Next, we discovered it was better to perform the filtration one day after adding the ammonia instead of immediately after adding it. The other two processes could be treated under substantially the same conditions as in the case of dephosphorization slag, and high-purity phosphorus was obtained.


Enhancement of the Catalytic Activity Associated with Carbon Deposition Formed on NiO/Al2O3 During the Dehydrogenation of Ethane and Propane

In the recent study, the dehydrogenation of isobutane to isobutene was accomplished using a NiO/ -Al2O3 catalyst, and significant improvement in the time-on-stream yield of isobutene was accomplished. During the normal catalytic dehydrogenation of alkanes, the catalyst is covered by the carbon deposition that is generated during the reaction, which drastically reduces activity with time-on-stream. Therefore, no examples of the catalytic dehydrogenation of isobutane have yet been reported. This study used either ethane or propane as a source of isobutane to examine whether the activity was improved with time-on-stream. As a result, in the dehydrogenations of both ethane and propane on a NiO/ -Al2O3 catalyst, the catalytic activity decreased with time-on-stream when the supporting amounts of NiO was small. By contrast, when the supporting amount of NiO was large, the catalytic activity improved with time-on-stream. The results using a NiO/ -Al2O3 catalyst with small and large NiO loadings were similar to those of isobutane dehydrogenation and it was confirmed that the dehydrogenation activity was improved with time-on-stream in the catalytic dehydrogenations of ethane, propane, and isobutane using large NiO loadings. Intermediate behavior using a moderate amount of NiO loading, which was not detected in the dehydrogenation of isobutane, was also observed, which resulted in a maximum yield of either ethylene or propylene at 2.0 or 3.25 h on-stream, respectively. We concluded that the reason the catalytic activity did not improve with time-on-stream when using a NiO/ -Al2O3 catalyst was because the supporting amount of NiO was too small. These results show that activity with time-on-stream could also be improved in the dehydrogenations of other alkanes.

Journal of Chemical Engineering of Japan


Carbon Deposition Assisting the Enhancement of Catalytic Activity with Time-on-Stream in the Dehydrogenation of Isobutane over NiO/Al2O3

In the transformation reaction of alkanes to alkenes via catalytic dehydrogenation, it is generally accepted that the so-called catalytic deactivation behavior will occur. This phenomenon causes a drastic reduction in activity with time-on-stream. It is understood that carbon deposition generated during the reaction then covers the surface of the catalyst, and this leads to a drastic decrease in activity. However, contrary to this common wisdom, our laboratory reported that the dehydrogenation of isobutane to isobutene on NiO/γ-Al2O3 within a specific range of NiO loading in the presence of CO2 actually improved the yield of isobutene with time-on-stream. Since few such cases have been reported, in this study, isobutane was dehydrogenated in the presence of CO2 using NiO/α-Al2O3 as the catalyst with 20% NiO loading and improvement was again observed. In order to investigate the cause of the improvement, both NiO/γ-Al2O3 and NiO/α-Al2O3 with 20% NiO loading were examined in detail following the reaction. According to TEM analysis, both catalysts were covered with a large amount of carbon deposition after the reaction, but there was a difference in the types. The carbon deposition on NiO/γ-Al2O3 had a fibrous nature while that on NiO/α-Al2O3 appeared to be a type of nanowire. Raman spectroscopy revealed that the carbonaceous crystal growth properties of two forms differed depending on the support. In particular, a catalytically active species of metallic nickel was formed in a high degree of dispersion in and on the above two forms of carbon deposition during the reaction, and this resulted in high activity even if the catalyst was covered with a carbon deposition.


Elution Behavior of Dephosphorization Slag to Various Acids and effect of Addition of Aqueous Alkali to Acid Eluate

We recently developed a method for efficiently recovering phosphoric acid from dephosphorization slag. The most important processes in this recovery technique involve elution of the dephosphorization slag into an acid solution (acid-elution process) and the addition of an alkali to the acid eluate to form a precipitate (alkali-precipitation process). Ultimately, we settled the use of an aqueous nitric acid solution for the acid-elution step, while an aqueous ammonia solution proved to be the optimal choice to accomplish alkali precipitation. Herein, we describe the procedures used to compare the utility of nitric acid with that of hydrochloric acid, sulfuric acid, and citric acid in the acid-elution process, and describe our comparison of an aqueous sodium hydroxide with that of an aqueous ammonia in the alkali-precipitation process. Finally, we summarize our findings on the acids and alkalis that proved to be suitable for this technology.

最近，脱リンスラグからリン酸を効率的に回収する方法を開発した． この回収技術で最も重要なプロセスには，脱リン酸化スラグの酸性溶液への溶出(酸溶出プロセス)と，酸溶出液へのアルカリの添加による沈殿物の形成(アルカリ沈殿プロセス)である． 最終的に，酸溶出ステップに硝酸水溶液を使用することにしたが，アルカリ沈殿を実現するには，アンモニア水溶液が最適な選択であることが明らかになった． ここでは，酸溶出プロセスにおける硝酸の有用性と塩酸，硫酸，およびクエン酸の有用性を比較するとともに，水酸化ナトリウム水溶液とアンモニア水溶液の有用性との比較した． アルカリ沈殿プロセス． 最後に，この技術に適していることが証明された酸とアルカリに関する研究結果を要約した．


Recovery of Phosphoric Acid and Calcium Phosphate from Dephosphorization Slag

We previously reported that by adding aqueous ammonia to the nitric acid extract of dephosphorization slag, a solid with enhanced concentrations of calcium and phosphorus, could be recovered. The present study shows that a considerable amount of manganese and iron also remains, however, which creates difficulties in directly reusing the recovered solid. The recovered material was again dissolved in nitric acid and the resultant filtrate was passed through a cation exchange resin that mostly removed various cations from the yield of an aqueous phosphoric acid solution. The recovery of phosphoric acid was confirmed via 31P NMR. Furthermore, when calcium nitrate was added to this aqueous solution, calcium hydroxyapatite, which was converted to calcium phosphate after the calcination at 1073 K. Phosphoric acid, calcium hydroxyapatite, and calcium phosphate are raw materials that are used to produce various industrial products containing phosphorus, and the suggested process greatly improves the technology for recovering phosphorus-containing materials that are mostly used as fertilizer.


Synthesis of Chemical Precursors via the Catalytic Hydrogenation of 2-Chloropropene

Allyl chloride is a synthetic intermediate that is used as an alkylating agent for pharmaceuticals, and is commonly synthesized at production sites related organochlorides. Allyl chloride is also the raw material that serves as a cross-linking agent for synthetic resins. In that particular synthesis process, however, the by-product 2-chloropropene (2-PEN) is a problem because it essentially has no practical use. In this study, an effective use for 2-PEN was investi-gated in the syntheses of 2-chloropropane (2-PAN) and propylene, which are precursors for various chemical products. To accomplish this, 2-PEN was hydrogenated on commercially available palladium catalysts such as OleMax 201, Ole-Max 301, OleMax 600, and HyFlex 500. The maximum yield of 2-PAN (10.6%) was detected at 348 K, P(H2) = 13.5 kPa and P(2-PEN) = 8.8 kPa, on OleMax 600 (0.5 g), while the maximum yield of propylene (26.0%) was realized under the same reaction conditions, with the exception of using at P(H2) = 7.9 kPa on HyFlex 500 (0.5 g). The selective formation of propylene such as 8.9, 100, and 8.9% for the conversion of 2-PEN, the selectivity of propylene, and the yield of propylene, respectively, were realized on OleMax201. The selective formation of 2-PAN, however, was not observed on all catalysts. Palladium loading strongly influenced the catalytic activity, but had none on either the specific surface area, or basic and acidic properties.

アリルクロライドは，医薬品のアルキル化剤や合成樹脂の架橋剤の原料として使用される合成中間体であり，有機塩素化合物に関連する生産現場で通常に合成される．しかし，合成プロセスによっては，用途の少ない2-クロロプロペン(2-PEN)が副生するため，問題となっている．本研究では，2-PENの有効利用を目的として，2-PENからさまざまな化学製品の前駆体である2-クロロプロパン(2-PAN)とプロピレンの合成を検討した．このために，OleMax 201，Ole-Max 301，OleMax 600，HyFlex 500などの市販のパラジウム触媒を用いて2-PENの接触水素化を検討した．348 K，P(H2) = 13.5 kPaおよびP(2-PEN) = 8.8 kPaの反応条件で， OleMax 600(0.5 g)触媒により，2-PANの最大収率(10.6%)が検出された．一方，プロピレンの最大収率(26.0%)は，P(H2) = 7.9 kPa，HyFlex 500(0.5 g)触媒を用いた以外は同じ反応条件とした場合に検出された． OleMax201では，2-PENの転化率，プロピレンの選択性，およびプロピレンの収率が，それぞれ8.9，100，および8.9%となり，プロピレンの選択的合成が実現された．一方，2-PANの選択的合成はすべての触媒で観察されなかった．パラジウムの担持量が触媒活性に強く影響したが，比表面積，塩基性および酸性は触媒活性に影響しなかった．


Improvement of Propylene Epoxidation Caused by Silver Plasmon Excitation by UV-LED Irradiation on a Sodium-Modified Silver Catalyst Supported on Strontium Carbonate --- Special Issue: Catalytic Epoxidation Reaction

The effect that UV-LED irradiation exerted on a sodium-modified silver catalyst supported on strontium carbonate (Ag-Na/SrCO3) was examined during an epoxidation of propylene to pro-pylene oxide. Based on our previous study, we used Ag(56)-Na(1)/SrCO3 in this study. The num-bers in parentheses refer to the weight percentage of silver and sodium. Although this catalyst system did not contain typical photocatalysts such as titanium oxide or tungsten oxide, UV-LED irradiation of Ag(56)-Na(1)/SrCO3 resulted in an evident improvement in the selectivity and yield of propylene oxide. Such an advantageous effect of UV-LED irradiation could not be dis-cussed based on the bandgap used in photocatalysts, and, therefore, we proposed a mechanism based on the plasmon excitation of silver, which could be accomplished using the irradiation wavelength of UV-LED to produce electrons. Since the lifespan of these electrons is expected to be short, it is difficult to place them into direct contact with the gas phase of oxygen. Once the generated electrons move to SrCO3, however, the lifespan is improved, which could allow suit-able contact with oxygen in the gas phase to form active oxygen. If the oxygen is active for epoxidation as hydrogen peroxide, this could explain the improvement in activity from UV-LED irradiation.

プロピレンのプロピレンオキシドへのエポキシ化に対して炭酸ストロンチウムに担持されたナトリウム修飾銀触媒(Ag-Na/SrCO3)を用いた場合のUV-LED照射も影響を検討した．既報の結果に基づいて，この研究ではAg(56)-Na(1)/SrCO3を使用した．なお，括弧内の数字は，銀とナトリウムの重量パーセントを示す．この触媒には，酸化チタンや酸化タングステンなどの，一般的な光触媒は含まれていないが，Ag(56)-Na(1)/SrCO3触媒にUV-LEDを照射すると，酸化プロピレンの選択性と収率が明らかに向上した．このようなUV-LED照射の加速な効果は，光触媒の議論で汎用されるバンドギャップではできなかったため，UV-LEDの照射波長により発現する銀のプラズモン励起に基づくメカニズムを提案した．UV-LEDを銀のナノ粒子にい照射してプラズモン電子が生成する．これらの電子の寿命は短いと予想されるため，酸素の気相と直接接触させることは困難である．ただし，生成された電子がSrCO3に移動すると，寿命が長くなり，気相中の酸素と適切に接触して活性酸素を形成できるようになる．酸素が過酸化水素のようなエポキシ化に対して有効な活性酸素である場合，本研究で観測されたUV-LED照射による活性の改善を説明できる．


Enhancement of the Catalytic Activity Associated with Carbon Deposition Formed on NiO/γ-Al2O3 Catalysts during the Direct Dehydrogenation of Isobutane

The dehydrogenation of isobutane in the presence of CO2 over NiO supported on γ-Al2O3 was examined. For comparison, Cr2O3 supported on γ-Al2O3 was also used. It is generally accepted that a catalyst used for the dehydrogenation of various alkanes will suffer catalyst deactivation due to the formation of carbon deposits. In the present study, the yield of isobutene was significantly decreased with time-on-stream due to carbon deposition when using Cr2O3(x)/γ-Al2O3, in which x indicates the loading of a corresponding oxide by weight %. However, carbon deposits also were evident on NiO(x)/γ-Al2O3, but the yield of isobutene was enhanced with time-on-stream depending on the loading (x). This indicates that the contribution of the carbon deposition in the dehydrogenation on NiO(x)/γ-Al2O3 definitely differed from that on an ordinary catalyst system such as Cr2O3(x)/γ-Al2O3. In order to confirm the advantageous effect that carbon deposition exerted on the yield of isobutene, NiO(x)/γ-Al2O3 was first treated with isobutane and then the catalytic activity was examined. As expected, it became clear that the carbon deposits formed during the pretreatment contributed to the enhancement of the yield of isobutene. The presence of a Ni-carbide species together with the metallic Ni that was converted from NiO during dehydrogenation definitely enhanced of the yield of isobutene. Although carbon deposition is generally recognized as the main cause of catalyst deactivation, the results of the present study reveal that carbon deposition is not necessarily the cause of this phenomenon.


Enhanced Phosphate Removal by Thermally Pretreated Waste Oyster Shells

Journal of Material Cycles and Waste Management


Dependence of Phosphorus Recovery on Acid Type during Dissolution-Precipitation Treatment of Incineration Ash of Chicken Manure

In order to utilize chicken manure as a source of phosphorus, we used dissolution-precipitation treatment to recover phosphorus from the incineration ash of chicken manure (IACM), which was used as fuel to power a boiler. In order to recover useful phosphorus-containing solids from IACM, it was dissolved into aqueous solutions of either nitric acid, hydrochloric acid, or sulfuric acid to elute phosphorus together with various component elements, followed by the use of aqueous NH3 to form a precipitate containing phosphorus. In using nitric acid and hydrochloric acid, calcium phosphate species such as calcium hydroxyapatite (Ca10(PO4)6(OH)2) and monetite (CaHPO4) were obtained following the precipitation treatment. By contrast, the use of sulfuric acid resulted in the precipitation of magnesium ammonium phosphate (MAP) species such as struvite (MgNH4PO4∙6H2O) and dittmarite (MgNH4PO4∙H2O). Both the calcium phosphate and MAP species can be used as a slow-acting fertilizer containing phosphorus, while the MAP species could be simultaneously used as a slow-acting fertilizer containing nitrogen. It is noteworthy that the calcium phosphate species obtained in the present study was equivalent to phosphate rock, which is widely used as a raw material in phosphorous-based industries, and the natural sources of this material could be depleted in the near future. Though IACM has not been used effectively until now, this new resource shows promise as s viable alternative to the dwindling supply of the natural sources of phosphorus.

Journal of Chemical Engineering of Japan


Effect of Cerium Addition to Bismuth-molybdenum Complex Oxide Catalyst for Partial Oxidation of Propylene to Acrolein

Ce addition to a Bi-Mo complex oxide catalyst supported on SiO2 was examined for its effect on the partial oxidation of propylene to acrolein. The catalyst consisted of an oxygen-supply phase where the lattice oxygen in Mo-oxide was doped with transition metals such as Fe, Ni and Co and was supported by SiO2 and a catalytic-active phase that involved hydrogen-abstraction from a reactant in the Bi-center of Bi-Mo oxide, which was supported by an oxygen-supply phase. In the present study, Ce was added during the oxygen-supply phase in order to enhance its redox nature. An advanta-geous effect of Ce addition was observed particularly under oxygen-rich conditions in the feed stream. For example, at P(C3H8) = 10.1 kPa and P(O2) = 15.5 kPa at 623 K, the yield of acrolein was slightly enhanced from 57.6% with 0% Ce doping to the catalyst to 65.3% with 20% Ce doping to the catalyst at 6 h on-stream. However, under greater oxy-gen-rich conditions at P(C3H8) = 10.1 kPa and P(O2) = 31.0 kPa at 623 K, the yield of acrolein was enhanced approxi-mately twice from 27.7% with 0% Ce doping of the catalyst to 61.8% with 20% Ce doping of the catalyst at 6 h on-stream. Analysis using XPS for the catalysts previously used for the reaction in the absence of gaseous oxygen con-firmed the unique redox behavior between the catalytic-active phase and the oxygen-supply phase as the lattice oxygen in the catalytic-active phase was replenished from the oxygen-supply phase to maintain its surface properties over the catalytic-active phase. The XPS results and the remarkable effect of Ce addition to the oxygen-supply phase under ox-ygen-rich conditions confirmed the correctness of the concept of the catalyst preparation consisting of an oxy-gen-supply phase and a catalytic-active phase was correct.

SiO2に担持されたBi-Mo複合酸化物触媒へのCe添加の効果を，プロピレンのアクロレインへの部分酸化について検討した．本研究で検討した触媒は2つの相で構成されおり，SiO2に担持されたMo-酸化物にFe, Ni, Coを導入した格子酸素に対する酸素供給相，およびその周りに担持した反応物からの水素引き抜きを行うBiサイトを持つBi-Mo酸化物の触媒活性相の2相である．本研究では，酸素供給相の酸化還元性を高めるために，酸素供給相にCeを添加した． Ce添加による良好な結果は，酸素リッチの原料ガスを用いた際に観測された．例えば，P(C3H8) = 10.1 kPa，P(O2) = 15.5 kPa，T = 623 K，通塔時間6時間において，Ceの添加率が0%から20%に増加させても，アクロレインの収率は，57.6%から65.3%へわずかに増加しただけであった．一方，同条件で，P(O2) = 31.0 kPaとした酸素リッチ条件では，Ceの添加率が0%から20%に増加させると，アクロレインの収率は，27.7%から61.8%へと約2倍増加した．原料ガス中に酸素を加えずに反応を繰り返した後の触媒のXPS分析により，触媒活性相と酸素供給相の間のユニークな酸化還元挙動が確認され，触媒活性相の格子酸素は酸素供給相から補充されて，触媒活性相表面の状態が維持されることが明らかになった．これらのXPSによる結果と，酸素リッチ状態での酸素供給相へのCe添加の触媒活性への顕著な効果に基づいて，酸素供給相と触媒活性相からなる触媒調製方法の概念が正しいことを明らかにした．

Journal of the Japan Petroleum Institute


Oxidative Dehydrogenation of Methane When Using TiO2- or WO3-Doped Sm2O3 in the Presence of Active Oxygen Excited with UV-LED --- Special Issue: Photocatalytic Oxidation/Ozonation Processes

There are active oxygen species that contribute to oxidative coupling or the partial oxidation during the oxidative dehydrogenation of methane when using solid oxide catalysts, and those species have not been definitively identified. In the present study, we clarify which of the active oxygen species affect the oxidative dehydrogenation of methane by employing photo-catalysts such as TiO2 or WO3, which generate active oxygen from UV-LED irradiation conditions under an oxygen flow. These photo-catalysts were studied in combination with Sm2O3, which is a methane oxidation coupling catalyst. For this purpose, we constructed a reaction system that could directly irradiate UV-LED to a solid catalyst via a normal fixed-bed continuous-flow reactor operated at atmospheric pressure. Binary catalysts prepared from TiO2 or WO3 were either supported on or kneaded with Sm2O3 in the present study. UV-LED irradiation clearly improved the partial oxidation from methane to CO and/or slightly improved the oxidative coupling route from me-thane to ethylene when binary catalysts consisting of Sm2O3 and TiO2 are used, while negligible UV-LED effects were detected when using Sm2O3 and WO3. These results indicate that with UV-LED irradiation the active oxygen of O2 from TiO2 certainly contributes to the activation of methane during the oxidative dehydrogenation of methane when using Sm2O3, while the active oxygen of H2O2 from WO3 under the same conditions afforded only negligible effects on the activation of methane.

本研究は，酸素流通下でUV-LED照射すると活性酸素を生成するTiO2やWO3などの光触媒を用いて，どのような活性酸素種がメタンの酸化脱水素に影響を与えるかという点を解決する一環として行われた．常圧固定床流通式反応装置を用い，大気圧下で直接UV-LEDを固体触媒に照射できる反応系を構築した．触媒には，メタン酸化カップリング触媒であるSm2O3とTiO2またはWO3から二元系触媒を選択し，それぞれ担持法および混練法で調製した．Sm2O3とTiO2からなる二元系触媒を使用した場合，UV-LED照射によりメタンからCOへの部分酸化が改善され，メタンからエチレンへの酸化カップリングもわずかに改善された．一方，Sm2O3とWO3からなる二元系触媒を使用した場合，UV-LED効果はほとんどなかった．UV-LED照射により，TiO2からの発生する活性酸素であるO2‒はSm2O3を使用する場合には，メタンの酸化脱水素におけるメタンの活性化に寄与するが，WO3から発生する活性酸素であるH2O2はほとんど効果を示さないと結論づけた．


Effects of different silica intermediate layers for hydrogen diffusion enhancement of palladium membranes applied to porous stainless steel support

Porous stainless steel (SUS) supports were modified with double intermediate layers, silicalite-1 and -alumina, to enhance the hydrogen diffusion of a thin palladium membrane. One of layers, silicalite-1, was prepared using the hydrothermal synthetic method on porous SUS supports. The differences in expansion/contraction behaviors caused by different thermal coefficients of expansion between silicalite-1 and the SUS resulted in a lowering of the durability of the membrane. Intermediates layers of mesoporous MCM-48 powders or commercial spherical non-porous silica particles were then applied to porous SUS supports via aspiration, -alumina was introduced by dip-coating, and the Pd membrane was subjected to electro-less plating. H2 permeance of the Pd membrane (membrane thickness: 11 m) containing spherical silica particles was around 10x10-6 molm-2s-1Pa-1 at 600°C, which was higher than that of the Pd membrane (membrane thickness: 7 m) containing MCM-48. The durability of the Pd membrane containing spherical silica particles was higher than that of the version containing MCM-48 powders. These results suggest that commercial spherical non-porous silica particles will uniformly occupy the pores of the SUS tubes and enhance the H2 permeance and durability of the Pd membrane.


Alkali Treatment of Commercial Silicoaluminophosphate Molecular Sieves (SAPO-34) Enhances the Water Adsorption and Desorption Properties

Commercial silicoaluminophosphate molecular sieves (SAPO-34) received alkali treatment with either NaOH (0.2, 0.01, 0.005, or 0.001 M) or NH4OH (0.005 M). Treatment with NaOH (0.005 M) increased the water adsorption initial rate of SAPO-34 by 1.4-fold. The alkali treatment introduced Na+ adsorption sites into the SAPO-34. The desorption ratio (adsorption at 30 and desorption at 100) was 88.2% higher than the original rate (84.3%). On the other hand, after alkali treatment of SAPO-34 using NH4OH (0.005 M), calcination resulted in the highest desorption ratio at 91.3%. When combined with calcination, alkali treatment with NH4OH introduced H+ adsorption sites into SAPO-34, H+ adsorption sites feature low levels of interaction with water, which enhanced the desorption ratio, but decreased the initial adsorption rate. These results indicate that treating commercial SAPO-34 with 0.005 M NaOH enhances both the adsorption and desorption behaviors.

Journal of Encapsulation and Adsorption Sciences


Catalytic Activity and Coking Resistance on Hydroxyapatite for the Oxidative Dehydrogenation of Isobutane


Recovery of Phosphate Rock Equivalents from Incineration Ash of Chicken Manure by Elution-precipitation Treatment

In order to obtain calcium phosphates - a phosphate rock equivalent - from the incineration ash of chicken manure, which is obtained from power generation systems that use the manure for fuel, incineration ash was treated with an aqueous solution of nitric acid to elute phosphorus. By using 0.3 M of HNO3, most of the phosphorus could be eluted from 1.0 g of ash within 0.1 h. Compared with the composted chicken manure that was previously examined in our laboratory, the concentration of HNO3 was increased for this session of elution. Using the incineration ash of chicken manure made it possible to remove inorganic species at a lower boiling or sublimation temperature, and organic species by calcination in the power generation system. Compared with composted chicken manure, the concentrations of phosphorus contained in the incineration ash and the nitric acid extract were higher in the incineration ash. XRD analysis showed that the obtained nitric acid extract could be treated with aqueous NH3 to form a precipitation of poorly-crystallized calcium hydroxyapatite (Ca10(PO4)6(OH)2), which is one of main components in phosphate rock. In order to confirm the formation and purity of calcium phosphate species, the precipitation calcination was conducted at 1,078 K for 5 h. XRD revealed that the calcined solid was tricalcium phosphate, and no contamination was evident. These results reveal that a phosphate rock equivalent could be easily obtained from the incineration ash of chicken manure, which means that approximately 14% of the phosphate rock that is currently being imported into Japan could be replaced by this product.


Gas Phase Epoxidation of Propylene to Propylene Oxide on a Supported Catalyst Modified with Various Dopants

In the present study, the production of propylene oxide (PO) from propylene via gas phase epoxidation was investigated using various catalysts. Although Ag is known to be a highly active catalyst for the epoxidation of ethylene, it was not active in the present reaction. Both Al and/or Ti showed high level of activity, however, which resulted in confusion. The present study was conducted to solve such confusion. The intent of the present study was to solve such confusion. Although the employment of MCM 41 modified with Ti and/or Al was reported as an active catalyst for epoxidation, the combination resulted in a formation of PO that amounted to less than a 0.1% yield. Since this research revealed that the acidic catalyst seemed favorable for the formation of PO, versions of ZSM 5 that were both undoped and doped with Na, Ti and Ag were used as catalysts. In these cases, small improvements of 0.67 and 0.57% were achieved in the PO yield on H ZSM 5 and Ti ZSM 5. Based on the results of the Ti dopant and acidic catalysts, Ag metal doped on carbonate species with a smaller surface area was used as a catalyst. As reported, Ag Na/CaCO3 showed a greater yield of PO at 1.29%. Furthermore, the use of SrCO3 for CaCO3 resulted in a further improvement in the PO yield to 2.17%. An experiment using CO2 and NH3 pulse together with SEM and TEM examinations for Ag Na/CaCO3 revealed that the greatest amount of activity was the result of the greater particle size of metallic Ag rather than the acid base properties of the catalysts.


Modifying SBA-15 with Binary Elements of Chromium and Molybdenum for Improved Catalytic Performance in the Oxidative Dehydrogenation of Isobutane to Isobutene

In the oxidative dehydrogenation of isobutane to isobutene, selectivity and stability were improved by introducing chromium and molybdenum into SBA-15. The direct synthesis method (DM) was used to introduce these binary elements into SBA-15. Use of the DM resulted in a higher specific surface area of the catalyst and a greater dispersion of chromium and molybdenum species compared with a corresponding binary catalyst prepared using the incipient wetness impregnation method (IM). Selectivity to isobutene was improved, along with a decrease in the selectivities to CO and CO2 with the introduction of greater amounts of molybdenum, which suggests that molybdenum must suppress the tendency of isobutene to over-oxidate to either CO or CO2. The molybdenum species must be in close proximity to the chromium species, which results in the formation of an active Cr-O-Mo site.

Journal of Chemical Engineering of Japan


Enhancement of water adsorption-desorption performance of aluminophosphate molecular sieves (AlPO-5) substituted with several metals

Aluminophosphate molecular sieves (AlPO-5) were substituted with seven metals (Ca, Co, Mg, Ni, Sr, Cr and Fe). From XRD measurement, all patterns of seven substituted AlPO-5 were identical to that of the AFI structure. Except for Cr substituted for AlPO-5, they were mainly in a hexagonal pillar structure from SEM images. For Mg, Ni, Sr and Fe substituted for AlPO-5, the water adsorption capacity at 30 and the difference in the amount of adsorbed water between 30 (adsorption temperature) and 100 (desorption temperature) increased by the substitution. Although, for Fe substituted AlPO-5, the initial water adsorption rate was slightly decreased by the substitution, the water desorption temperature was equal for the temperature of AlPO-5. Because Fe substituted for AlPO-5 had about 1.8 times of water adsorption capacity at 30 and were able to be regenerated at 100, Fe substituted for AlPO-5 was most advantageous adsorbents.


Effect of Introduction of Trace Amount of Chromium Species in Improving Catalytic Performance of MCM-48 in Oxidative Dehydrogenation of Isobutane

The catalytic performance of MCM-48 was greatly improved by the introduction of a small amount of chromium during the oxidative dehydrogenation of isobutane. Various characterization procedures such as XRD, N2 adsorption-desorption isotherms, TEM, NH3-TPD, XPS, and XAFS were used to clarify the role that chromium played in the improvement, and XPS and XAFS returned the most valuable information. Both measurements revealed that the chromium species existed as Cr6+ inside the framework of MCM-48 before oxidative dehydrogenation, but was reduced to Cr3+ during the reaction. The characteristic pore nature of MCM-48 also contributed to an enhancement of the selectivity to isobutene via a suppression of any consecutive oxidation reactions.


Application of Si/SiC Ceramic Filters as Support for Structural Palladium Catalysts for the Reductive Decomposition of Aqueous Nitrite

A Si/SiC ceramic filter was used to support a structural palladium catalyst in a continuous fixed-bed flow reactor during a reductive decomposition of nitrite. A previous report described the use of non-porous alumina spheres coated with Pd/C, a carbon monolith impregnated with Pd or a structural catalyst consisting of a polyurethane sponge skeleton impregnated with Pd resulted either in negligible activity or a complete stoppage of the flow by increasing the pressure drop in the flow system. The use of a Si/SiC filter impregnated with palladium, however, overcame the demerits and resulted in an 11% conversion of nitrite in 60 min. The use of a Si/SiC filter coated with a char intermediate followed by impregnation with Pd (Pd/C/Si/SiC) resulted in a structural catalyst that enhanced the activity to yield a 33% conversion of nitrite in 60 min. When five Pd/C/Si/SiC structural catalysts were used, however, the complete decomposition was achieved in the same amount of time. Although improvement was previously observed by using an alumina intermediate, use of the char intermediate resulted in a new factor for activity improvement. The characterization results show that it was the affinity between aqueous nitrite and the intermediate rather than palladium dispersion that contributed the most to the improvement of activity.


Enhancement in Boiling Heat Transfer for Water Using a Polished Plate Surface

The thermal characteristic of a plate evaporator for boiling water have been experimentally investigated. Stainless-steel plates with five kinds of surface roughness (a mirror-polished surface and four kinds of polished plate surface, F2, F0, F-1, and F-2 polishing) were used for the investigation. The roughness order is F-2>F-1>F0>F2>mirror. The local boiling heat transfers were measured on the evaporator surface using ten thermocouples inside the evaporator. For a comparison of the heat transfer characteristic of the evaporator, the local boiling heat transfer coefficient was measured when the polishing direction was perpendicular or parallel to the water flow at a range of pressures (0.30.4MPa) and flow rates (2060mL/min). The results indicate that the local heat transfer coefficient increased with increasing vapor quality at all surface conditions. For F0 polishing, the heat transfer coefficient on the surface with perpendicular polishing was much larger than that on the surfaces with parallel and mirror polishing. In particular, the heat transfer coefficient of the perpendicularly polished surface (F2 and F0 polishing) was increased six-fold in comparison with that of the mirror surface at a vapor quality of 0.35. However, for the F-1 and F-2 perpendicularly polishing plates, the heat transfer coefficients were smaller than those of the F0 and F2 perpendicularly polishing plates. For the F2 perpendicularly polished plate, heat transfer enhancement was confirmed, along with an increase in the number of bubbling points, on increasing the system pressure. For the polished surface, the heat transfer coefficient increased with increasing flow rate. This indicates that the bubble formation cycle was promoted by an increased flow rate.


Introduction of a Small Amount of Chromium to Enhance the Catalytic Performance of SBA-15 for the Oxidative Dehydrogenation of Isobutane to Isobutene

Various solid oxide catalysts are active in the oxidative dehydrogenation of propane, but when these were used for the oxidative dehydrogenation of isobutane to isobutene, the yield was less than 2%. An improved yield of isobutene to 8% was obtained in the oxidative dehydrogenation of isobutane using folded-sheet mesoporous material (FSM-16) and mesoporous molecular sieve (MCM-41), either added or unadded with chromium via impregnation or template ion exchange methods. Further activity enhancement, however, could not be attained. In the present study, in order to introduce chromium cations into the framework of SBA-15 using a direct synthesis method, chromium nitrate was mixed with TEOS in an aqueous starting solution with pH adjusted to 1.5, which was followed by the hydrothermal treatment. Loading the resultant catalyst, SBA-15, with a small amount of chromium (1.84 wt% Cr-SBA-15) returned a greater yield of isobutene (15.4%) at 723 K, although previous report showed that SBA-15 supported with chromium oxide (CrOx/SBA-15) prepared via incipient wetness impregnation showed a lower yield of isobutene (11%) at 813 K. In order to explain such an improvement, the catalysts were characterized using XRD, TEM, N2 adsorption-desorption and NH3 temperature-programmed desorption. A substantial amount of specific surface area (1,610 m2/g) was detected in active Cr-SBA-15, although the structural and acidic nature of the catalyst showed the general properties of other mesoporous silicas. It is possible that when the Cr6+ species is converted from Cr3+, the great specific surface area of Cr-SBA-15 could be a factor in the oxidative dehydrogenation of isobutane to isobutene.


Template Effect of Phosphate Surfactant on Formation of Hydroxyapatite Nanostructures with Various Shapes

Various shaped hydroxyapatite nanostructures were prepared by phosphate surfactant selfassembly in aqueous solution. The structures of hydroxyapatite were greatly influenced by the sodium dodecyl phosphate (SDP) concentration. X-ray diffraction, transmission electron microscopy measurements, thermogravimetric analysis and fourier transform infrared spectra were performed to investigate their nanostructures. Spindle-type nanoparticles consisting of hydroxyapatite nanocrystals by an oriented attachment were obtained with low SDP concentration, whereas rod-shaped and sheetlike nanostructures formed in the two-dimensional water phase of the lamellar structure with high SDP concentration. These results indicate SDP molecules play a critical role in the formation of hydroxyapatite nanostructures.


Reductive Decomposition of Nitrite in a Continuous-Flow Reactor Using Fixed-Bed Structural Pd Catalysts

In order to decompose trace amounts of nitrite in drinking water under mild conditions, a fixed-bed filtering system that used structural catalysts was employed to filter recycled aqueous nitrite. High performance and continuous mass processing are generally accepted as requirements to catalyze the decomposition of aqueous nitrite. However, the use of a fixed-bed operation when recycling aqueous nitrite with palladium catalyst systems could result in either negligible activity when using a carbon monolith impregnated with Pd, or could stop the flow by enhancing the pressure drop when using non-porous alumina spheres coated with Pd/C or structural catalysts consisting of a polyurethane sponge skeleton impregnated with Pd. In the present paper, a Si/SiC ceramic filter was employed as a structural support to prevent pressure drop. When palladium was loaded onto the surface of the filter via electroless plating, continuous flow suitably continued, and the conversion of nitrite was 45% after 60 min. In contrast, when palladium was loaded after the coating of the filter with alumina, complete decomposition was achieved after 60 min under conditions corresponding to those used for the former system. X-ray diffraction, an N2 adsorption-desorption measurement, scanning-electron microscopy, and energy-dispersive X-ray spectroscopy analyses revealed that a higher dispersion of palladium on the latter structural catalyst resulted in the greatest level of activity for the reductive decomposition of aqueous nitrite.


Catalyst Deactivation of a Silica-supported Bismuth-molybdenum Complex Oxide and the Related Complex Oxides for the Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene

This study was an examination of the catalyst deactivation of a silica-supported bismuth-molybdenum complex oxide, and that of catalysts used in the absence of bismuth, for the oxidative dehydrogenation of 1-butene. Due to the detection of deactivation, the molar ratio of 1-butene against oxygen in the reactant gas was adjusted to a ratio similar to that used in industrial processes where reaction temperatures average 100 K higher. Regardless of the presence or absence of bismuth in the catalysts, the conversion of 1-butene was decreased by 6 h on-stream. Both the progress of the coking from the inlet to the outlet of the catalyst and the reduction of molybdenum in the catalysts directly contributed to the deactivation. X-ray photoelectron spectrometry revealed that a greater reduction of molybdenum in the near-surface region and a smaller partial pressure of oxygen (P(O2)) in the reactant gas, although the molybdenum on the surface was not reduced at all. This indicated that the lattice oxygen was pumped from the near-surface region to the surface during the reaction and the oxygen-poor conditions of the near-surface region both in the gas and catalyst phases were formed at a smaller P(O2), which resulted in the enhancements of both the reduction of molybdenum and that of coking. Based on the thermogravimetric analysis, the silica-supported bismuth-molybdenum complex oxide used at P(O2) = 4.1 kPa (color of the catalyst = black) was increased in weight while that used at P(O2) = 16.4 kPa (color of the catalyst = gray) showed a weight decrease, which indicated that the weight decrease caused by the reduction in molybdenum in the near-surface region used at 4.1 kPa was greater than the weight increase from the coking. It was concluded that the reduction in molybdenum followed by the coking on the catalyst surface were the main factors in the catalyst deactivation.

Journal of Chemical Engineering of Japan


Effects of Acidic-basic Properties on Catalytic Activity for the Oxidative Dehydrogenation of Isobutane on Calcium Phosphates, Doped and Undoped with Chromium

The catalytic activities of calcium hydroxyapatite (HAp) and β-type tricalcium phosphate (β-TCP) were examined for their use in the oxidative dehydrogenation (ODH) of isobutane. β-TCP was catalytically inactive for the ODH of isobutane, but stoichiometric HAp returned a high isobutene yield (5.6%). The isobutane conversion and isobutene selectivity of HAp depended on the atomic ratio of Ca/P. HAp with a Ca/P = 1.67 showed the highest levels for both isobutene selectivity and isobutene yield from among HAp catalysts with different Ca/P ratios. Based on a characterization of the acidic-basic properties, it was evident that these acidic-basic properties affect the catalytic performance of HAp, and that its basicity is necessary for high catalytic activity. To improve the catalytic activities of calcium phosphates, they were impregnated with Cr. Despite a much lower surface area for β-TCP, Cr-impregnated β-TCP showed a higher isobutene yield (up to 8.4%) than that of Cr-impregnated HAp. The results of the XPS measurement showed that the Cr3+ species on calcium phosphates, together with the basicity, worked as active sites in the ODH of isobutane.


High Thermal Stability Ceria Synthesized via Thermal Hydrolysis Route and Methane Combustion Performance

Enhancement of the thermal stability of a catalyst is an efficient way to improve the catalytic activity of a catalytic reaction performed at high temperature. In this study, cerium oxide (ceria, CeO¬2) with a high thermal stability was synthesized by controlling the agglomeration of the primary particles via the thermal hydrolysis of ceric nitrate, accompanied by testing for the catalytic combustion of methane (CH4). The specific surface area of this material after calcination at 1,173 K for 5 h was 50 m2/g, which was much higher than that of the two references materials (ceria made via precipitation of cerous nitrate using aqueous ammonia at 4.1 m2/g, and the Japan reference catalyst JRC-CEO-1 at 1.4 m2/g). The ceria made via thermal hydrolysis showed high crystallinity and a much higher pore volume, which resulted in excellent thermal resistance. For O2 conversion in ceria, catalyzed CH4 combustion at 923 K, the ceria created in this study demonstrated higher activity than that for either reference. The high CH4 combustion performance was due to the high specific surface area and to a superior oxygen storage capacity (OSC) even after a combustion test.

高温安定性をもつセリアを合成できることを纏めた論文．今回合成したセリアは1173Kで5時間焼成しても50 m2/gの比表面積を持つが，通常の参照触媒は1.4 m2/g，沈積法で調製した場合でも4.1 m2/gしかなく，今回報告したセリアの熱安定性は従来にはないものである．メタン燃焼に高温安定セリアを用いた場合，比較的低温度では，比表面積に相当する活性を与える一方，高温領域では触媒表面への吸着-脱離が律速段階からはずれすために，比表面積によらずほぼ一定の活性を示した．


Formation of Cerium Carbonate Hydroxide and Cerium Oxide Nanostructures by Self-Assembly of Nanoparticles Using Surfactant Template and Their Catalytic Oxidation


Hydrothermally Synthesized Ceria with a High Specific Surface Area for Catalytic Conversion of Ethanol to Ethylene

Morphological control can be used to improve the catalytic activity of cerium oxide (ceria, CeO2). For this study, ceria with a high specific surface area was synthesized via the hydrothermal reac-tion of ceric nitrate and was tested on the catalytic conversion of ethanol to ethylene. For a refer-ence, ceria was also synthesized via a precipitation reaction of cerous nitrate using aqueous am-monia. The Japan reference catalyst, JRC-CEO-1 also served as a reference. The specific surface area of the hydrothermally synthesized ceria was as high as that of JRC-CEO-1, but was much higher than that of either of the references after calcination at 873 K. Thermo-gravimetric analysis and IR spectroscopy revealed that the cerias made by hydrothermal and precipitation reactions consisted of high-purity CeO2, while the JRC-CEO-1 contained 1.5% decomposable functional groups (OH-, CO32-). For both ethanol conversion and ethylene selectivity in a catalytic dehydration reaction of ethanol, the activity of the hydrothermally developed ceria was higher than that for either of the references. The reaction pathway for the dehydration reaction of ethanol over ceria showed that the specific surface area and the basicity of the Lewis basic site of the ceria were specific influential properties. The high catalytic activity of the hydrothermally synthesized ceria derived from its high specific surface area and high-purity CeO2.

本研究で提案した調製法で合成した酸化セリウムは，シンタリング耐性が高いことが知られていたが，エタノールからエチレンへの接触反応の触媒として高活性を示し，今回の調製法で調製すると高表面積を持つ純度の高い酸化セリウムができることが原因であることを明らかにした．


Effects of Acid Treatment on the Acidic Properties and Catalytic Activity of MCM-41 for the Oxidative Dehydrogenation of Isobutane

Mesoporous silicas have shown promise as materials for solid catalysts or catalyst supports due to their unique characteristics. Metal-doped mesoporous silicas are known to be catalytically active in the oxidative dehydrogenation (ODH) of isobutane. However, heavy-metal-free mesoporous silicas have not been studied closely for their use as catalysts. In the present study, MCM-41 (#41 Mobil composition of matter) was acid-treated to enhance its catalytic activity, although pure MCM-41 was confirmed as catalytically inactive for the ODH of isobutane (isobutene yield = 0.9%). The pH of a slurry of as-synthesized MCM-41 was changed during acid treatment. A pH adjustment to 6.5 resulted in great improvement in catalytic activity (isobutene yield = 6.1%), but a pH adjustment to 4.5 resulted in insufficient improvement (isobutene yield = 4.5%). It was confirmed via XRD and N2 adsorption-desorption measurement that the pH adjustment to 4.5 degraded the ordered structure of MCM-41. This degradation would be a crucial factor that would render acid treatment less effective. In addition to the acid treatment, Al doping to MCM-41 was conducted. Al doping also greatly enhanced the acidity and catalytic activity of MCM-41.

酸で処理またアルミニウムで修飾したMCM-41が，イソブタンの接触酸化脱水素反応によるイソブテンへの触媒として高活性であることを明らかにした．従来は重金属による修飾が必須修であった本触媒系において，重金属を用いない環境に配慮した触媒を調製できることを明らかにした．


Recovery of Calcium Phosphates from Composted Chicken Manure

To recover phosphorus from composted chicken manure, a batch method with aqueous HNO3, HCl and H2SO4 was used to examine the elution behavior of the aqueous calcium and phosphate contained in the manure. Since the main components in manure are Ca2+ and K+ along with PO43- and those ions can be dissolved using an acidic eluate, it was expected that most of the aqueous Ca2+, K+ and PO43- could be obtained via the elution. Therefore, it seemed plausible that the removal of the aqueous K+ obtained by the elution of composted chicken manure would result in the formation of calcium phosphates. If calcium phosphates are formed, they can be used for phosphate rock, which also consists of various calcium phosphates. When using 0.1 mol/L HNO3, HCl or H2SO4, the elution behavior of the PO43- was not dependent on the acids. However, 0.1 mol/L H2SO4 was not sufficient for the elution of Ca2+, probably due to the precipitation of the calcium sulfate. The eluted amount of K+ using 0.1 mol/L HNO3 was lower than that using 0.1 mol/L of either HCl or H2SO4. Since the poor elution of K+ should enrich the concentrations of Ca2+ and PO43- in the acidic aqueous solution after the elution, it was suggested that aqueous HNO3 would be suitable as an eluate in the present system. After the elution of the composted chicken manure, when 0.1 mol/L HNO3 was used to adjust the solution pH of the acidic aqueous solution to greater than 6, Ca2+ and PO43- were precipitated, but K+ was not. The precipitation was calcium hydroxyapatite, one of the typical components of phosphate rock, which showed that composted chicken manure could be replaced phosphate rock as a new source of phosphorus.

コンポスト化鶏糞を硝酸水溶液による湿式処理を行い，得られた水溶液をアンモニアでpHを制御すると，リン鉱石の主成分であるリン酸カルシウムを高純度で得ることができ，枯渇資源リンを廃棄物鶏糞から効率よく取得できることが明らかになった．


Oxidative Dehydrogenation of Isobutane to Isobutene on Metal-doped MCM-41 Catalysts

MCM-41 (#41 Mobil Composition of Matter) is a favorable material for heterogeneous reactions because of its unique porous structure. However, the catalytic activity of MCM-41 for the oxidative dehydrogenation (ODH) of isobutane to isobutene is known to be quite low. In the present study, a metal-doping method was employed to improve this catalytic activity. Doping of Cr, Co, Ni, or Mo into MCM-41 resulted in a great improvement in the catalytic activity. Since chromium-doped MCM-41 (Cr-MCM-41) showed the greatest catalytic activity among these catalysts, its redox property was further analyzed via XPS, XAFS and H2-TPR techniques. The XPS spectrum of Cr-MCM-41 suggested that it has Cr3+ and Cr6+ species on its surface. Also, a pre-edge peak due to Cr6+ species was confirmed in the XANES spectrum of Cr-MCM-41. In H2-TPR measurement, Cr-MCM-41 was more reducible than crystalline Cr2O3, which showed low catalytic activity for the ODH of isobutane. The reducible Cr6+ species on Cr-MCM-41 contributed to an improvement in the catalytic activity of MCM-41.

Crで修飾したMCM-41が，イソブタンの接触酸化脱水素反応によるイソブテンへの触媒として高活性であることを明らかにした．種々より還元性の高い6価のCrが活性改善に寄与していることが明らかになった．


The effects of created mesopores in ZSM-5 zeolites by an alkali treatment on water adsorption

Three kinds of ZSM-5 zeolites (SiO2/Al2O3=23.8 (Na-form), 39.0 (NH4-form) and 193(NH4-form)) were alkali-treated, and the changes in structural and water adsorptive properties were investigated. With the alkali treatment, the MFI structure was kept; a siliceous species was selectively dissolved from the framework of a zeolite, and the mesopores were created in the zeolites. At the same time, NH4-form ZSM-5 zeolites (SiO2/Al2O3=39.0 and 193) were ion-exchanged to form Na in an aqueous solution of NaOH. In particular, for ZSM-5 (SiO2/Al2O3=23.8), the water adsorption property was changed with the alkali treatment. The difference in the amount of adsorbed water on the zeolite between 30℃ (adsorption temperature) and 100℃(desorption temperature) was increased by the treatment. The desorption temperature of water adsorbed at the stronger site was decreased from 106℃ to 72℃ with the alkali treatment. These results indicate that the introduction of mesopores in ZSM-5 contributed to the enhanced water adsorption properties.


Effect of the Template Ion Exchange Behaviors of Chromium into FSM-16 on the Oxidative Dehydrogenation of Isobutane

The template ion exchange of chromium cations into FSM-16 (#16 Folded Sheets Mesoporous Materials) for 247 h resulted in a 2.89 wt% incorporation of those cations into the FSM-16, although only a 0.3 wt% incorporation had previously been reported. The XRD pattern of the resultant solid (Cr-FSM-16) showed that the hexagonal structure characteristic of FSM-16 remained after the 2.89 wt% incorporation of chromium cations. XPS could be used to detect the Cr3+ and Cr6+ species on the surface of Cr-FSM-16. A pre-edge peak that was due to a tetrahedrally coordinated Cr6+ species was confirmed in the XANES spectrum of the Cr-FSM-16, which showed that the coordination state around some Cr species was similar to that around the Si species in FSM-16. With the increase in the amount of chromium cations in FSM-16, its catalytic activity and stability during the oxidative dehydrogenation of isobutane were evidently improved.

クロムカチオンのメソポラスシリカであるFSM-16へのテンプレートイオン交換挙動はが検討され，従来は0.3wt%までしかクロムをイオン交換できなかったが，247時間のイオン交換の結果2.89%まで導入できた．XRD分析よりクロムを導入しても構造は変化しなかったが，クロムは3価と6価のカチオンが検出され，特に6価のクロムはヘキサゴナル構造を取って取り込まれることがXAFSで確認された．このクロム導入FSM-16はイソブタンの酸化脱水素反応の触媒として高活性を示した．


Modification of commercial NaY zeolite to give high water diffusivity and adsorb a large amount of water

By using NaY zeolites as desiccant materials, commercial NaY zeolite was alkali treated with 1M NaOH aqueous solution and then Mg2+ ion-exchanged by 0.5M Mg(NO3)2 aqueous solution. Alkali treatment (AT) of NaY zeolite removed silicon atoms selectivity from the framework of Y-type zeolite and enhanced water diffusivity of Y-type zeolite. On the other hand, Mg2+ ion-exchange of NaY zeolite increased the amount of water adsorbed. Prepared Y-AT-Mg zeolite had both water adsorption velocity and a large difference of water adsorbed amount between adsorption at 30℃ and desorption at 100℃.

Journal of Colloid and Interface Science


Morphological effects of CeO2 nanostructures for catalytic soot combustion of CuO/CeO2


Effects of the Acidic Properties of FSM-16 on the Catalytic Conversion of 1,2-Propandiol in the Presence and Absence of Hydrogen

In our previous paper, we showed how the catalytic conversion of 1,2-propandiol to propanal using FSM-16 (#16 Folded Sheets of Mesoporous materials) when molded by wet treatment proceeded more favorably than when using FSM-16 molded by pressurization, while no comparison using other typical acidic catalysts and no examination of the acidic properties of FSM-16 was carried out. In the present study, the conversion using FSM-16 molded by wet-treatment and pressurization was compared with the use of typical acidic catalysts such as SiW12O40/SiO2 and MCM-41 (#41 of Mobil Composition of Matter) together with amorphous SiO2. Among these catalysts, FSM-16 molded by wet treatment showed the most suitable catalytic activity. In order to examine the effect of the molding procedure for FSM-16 on its structural and acidic properties, FSM-16 molded by both methods was examined using NH3-TPD, in-situ FT-IR using NH3 as a probe molecule and Hammett indicators together with XRD and TEM. According to Zaitsev's rule, the present conversion should afford acetone rather than propanal, which indicates that it would proceed via hydro-cracking. Therefore the conversion of 1,2-propandiol using FSM-16 was also examined in the presence and absence of hydrogen. Furthermore the hydrations of 1- and 2-propanol when using FMS-16 were also examined. Based on the results obtained from this investigation, it was concluded that the conversion using a more acidic FSM-16 molded by wet treatment proceeded through dehydration rather than through hydro-cracking.

我々は，FSM-16が1,2-プロパンジオールからプロパナールへの高活性触媒であることを見出した．本論文では，高活性の発現因子を解明するため，構造解析と酸性質の詳細な検討を行い，ヘキサゴナル構造を保持した，酸性質の高い触媒が活性を与えることを示した．さらに，反応機構が水素化分解機構か，脱水素機構化という点を原料ガスに水素を添加して検討し，脱水機構で進むことを明らかにした．

Journal of Chemical Engineering of Japan


Recovery of the Phosphorus from the Nitric Acid Extract of Powder Collected in a Bag Filter during the Recycling of Used Fluorescence Tubes

rescence tubes (bag-powder), the batch method with aqueous HNO3 was used to examine the elution behavior of aqueous phosphate contained in the bag-powder. The main components of the bag-powder included Ca2+, PO43- and Y3+ along with Si4+, Sr2+ and lanthanide cations such as La3+ and Ce4+. Therefore, it seemed possible that, with the selective dissolution of Ca2+ and PO43- from the bag-powder, those lanthanide cations in the residue could be enriched. With the batch method, most of the phosphate in the bag-powder was dissolved within 0.2 min using 1.0 mol/L HNO3. The dissolution behavior of calcium cation was similar to that of the phosphate. In contrast, the dissolution of yttrium, the content of which was the highest among the lanthanide cations in the bag-powder, was increased with the dissolution times, reaching complete dissolution after 24 h. The Sr2+, La3+ and Si4+ in the bag-powder, however, did not dissolve under the same conditions. Although Ca2+, PO43- and Y3+ were the main components in the nitric acid extract, Y3+ was separated as YPO4 at pH = 4.0, while Ca2+ and PO43- were separated as calcium phosphates at pH= 7.0. These results revealed that the separation of calcium phosphates, YPO4 and some residue was possible, and resulted in the enrichment of lanthanide cations along with the recovery of phosphorus from the bag-powder. Using the present technique, 91% of the P in the bag-powder was recovered.

回収蛍光管処理後のバグフィルター回収粉末には，Ca2+, PO43-，Y3+，Si4+, Sr2+，La3+ やCe4+などが含まれている．この粉末を酸性溶媒で溶出処理を行い，アンモニア水により，pH=4.0にして，Y3+を回収し，さらにpH=7.0とすることにより，高純度のリン酸カルシウムを回収することができた．特にリンは91%回収することができ，枯渇資源リンとレアアースのY3+を安価で，容易に分離濃縮できることを明らかにした


Acidic Properties of Various Silica Catalysts Doped with Chromium for the Oxidative Dehydrogenation of Isobutane to Isobutene

Although previous researchers have found that FSM-16 (#16 Folded Sheet Mesoporous material) doped with chromium and related Cr-doped silica catalysts has shown great activity for the oxidative dehydrogenation of isobutane to isobutene, information on the nature of these catalysts is insufficient. For this study, three types of Cr-doped silica catalysts were prepared by applying the template ion exchange method. CrOx/FSM-16 and CrOx/SiO2 were used as references. These catalysts were used for oxidative dehydrogenation, which was then characterized via various techniques. The most active catalyst was Cr-doped silica, which did not have the hexagonal structure that is characteristic of mesoporous FSM-16. Various characterizations showed that the catalytic activity of the Cr-species, stemmed from a weak acidic nature and a redox nature that originated from the combination of silicate and a Cr cation, as opposed to the hexagonal structure and strong acidic nature of FSM-16.

前報でCrで修飾したFSM-16がイソブタンの接触酸化脱水素反応によるイソブテンに対して優れた活性を示すことを示した．本論文では，活性の発現因子を明らかにするために，基準となるCrOx/FSM-16やCrOx/SiO2触媒とともに，活性試験，構造解析，酸性質の詳細な検討を行った．その結果，FSM-16のメソ構造を破壊し，中程度の酸強度，酸量を持つCrで修飾したFSM-16が高活性を示すことを明らかにした．特に，Crのレドックス挙動とFSM-16の酸性質の相乗作用で活性が発現していることが確認された．


Enhanced Photocatalytic Hydrogen Evolution from Water by Niobate Single Molecular Sheets and Ensembles

We report single molecular sheets of niobate prepared by a simple bottom-up approach using hydrothermal synthesis of niobium ethoxide with the aid of triethanolamine as a structural modifier: the high kinetic stability of these molecular entities against self-assembly allows them to mix well with other colloids and facilitates their extensive electronic interactions and thus photocatalytic hydrogen evolution activity from water is much enhanced over composite of single niobate sheets with graphene and MoS2 due to efficient electron transfer and charge separation.


Layered Titanate Nanosheets Prepared by a Surfactant-Templating Approach: Effects of Lamellar Mesostructure on Surface Functionality


Recovery and Enrichment of Phosphorus from the Nitric Acid Extract of Dephosphorization Slag

A method for the recovery and enrichment of the phosphate from dephosphorization slag was examined. First, the elution of aqueous phosphate from dephosphorization slag using aqueous HNO3 was examined using both the batch and flow methods. With the batch method, 82% of the dephosphorization slag could be dissolved within 30 min using 1.0 mol/L HNO3, indicating that the batch method could be used for mass processing to extract phosphorus in the bulk phase, but all components contained in the slag were unselectively dissolved. In contrast, by using 0.05 mol/L HNO3 via the flow method, 22% of the slag was dissolved for 100 min giving a more selective dissolution of phosphate from the slag compared with the batch method, which indicated that this method would be incompatible with mass processing for the purpose of extracting phosphorus in the bulk phase. In order to remove the Fe-species in the aqueous solution obtained by the batch method using 1.0 mol/L HNO3, which has been referred to as the ``slag solution,'' it was necessary to add calcium hydroxyapatite (CaHAp) to the slag solution. The optimal conditions for the removal of Fe-species using CaHAp were observed at a solution pH of ca. 1.5, which resulted in 100% removal of the Fe-species after 4 h. When the pH of the slag solution was adjusted to 7.0 after removing the Fe species, a pale pink solid sample was precipitated. The amounts of phosphate in the slag solution and in the pink solid were 3.5 and 42.0 mol%, respectively, indicating that the treatment suggested in the present study could be used for the recovery and enrichment of phosphate, that is, phosphorous, from dephosphorization slag.

脱リンスラグからのリンの回収と濃縮について検討した．回分式反応器を用いて脱リンスラグを1.0 mol/L HNO3で処理を行うと82%溶解できたが，リンを選択的に溶出できなかった．そこで0.05 mil/L HNO3で処理すると22%しか溶解できなかったが，リンを比較的選択的に溶出できた．溶解後に共存する鉄をカルシウム水酸アパタイトで除去し，溶液のpHを7.0にすることにより42%のリンを含むリン化合物を溶出させることができた．


Effect of Reaction Temperature and Steam to Carbon Ratio on Hydrogen Production for Steam Reforming of Bio-Ethanol Using the Palladium Membrane Reactor

The steam reforming of bio-ethanol has been carried out to compare with reagent ethanol using a palladium membrane at several reaction conditions (673 or 873 K, ΔP=0.10 MPa and steam-to-carbon ratio (S/C)=4-10). The raw material of these experiments was surplus bio-ethanol, which is one of the by-products in fermentation with sulfuring process in cornstarch production. As a result, the amount of total H2 formation for bio-ethanol was comparable to that obtained with reagent ethanol under the same conditions. However, for bio-ethanol, the values of hydrogen permeate flow and hydrogen purity were smaller than that of reagent ethanol. In contrast, the amount of CO formed from bio-ethanol was greater than that from reagent ethanol. It is considered that carbon, which has a negative influence on the hydrogen-permeability of the palladium membrane, was produced from CO. The amount of CO was significantly decreased by lowering the temperature from 873 to 673 K. Moreover, CO was also decreased by increasing S/C and was not detected over S/C of 8. However, the amount of total hydrogen production and hydrogen permeate flow decreased by increasing the S/C ratio. Therefore, the best condition for hydrogen production from bio-ethanol using the palladium membrane reactor was at 673 K and S/C=8.


Oxidative Dehydrogenation of Isobutane to Isobutene on FSM-16 Doped with Cr and Related Catalysts

The oxidative dehydrogenation of isobutane to isobutene was examined for use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% could be achieved. The activity depended on the molding procedure of the catalyst and the doping method of the chromium species. In the present study, 8.8 and 8.3% of the yield of isobutene were obtained at 0.75 and 6 h on-stream for the catalyst (Cr-loading; 6.2 wt.%) molded using wet treatment but not pressurization treatment, in which the chromium species were directly added into the aqueous solution containing raw FSM-16 (hydrated sodium silicate powder) at an initial stage of the catalyst preparation. The structure information was based on XRD, the specific surface area was determined using a conventional BET nitrogen adsorption and the loading of chromium was estimated using ICP. All those parameters combined with the molding method indicated that the catalytic activity was more influenced by the loading of chromium into bulk but not on surface of the catalyst rather than by the hexagonal structure of FSM-16 and the surface area.

クロムで修飾したFSM-16および関連触媒によるイソブタンからイソブテンへの酸化脱水素が検討された．FSM-16の調製段階時にクロムを導入し，湿式成型した触媒を用いたところ，通塔45分および4.5時間後に8.8および8.3%の目的を超えるイソブテン収率を得た．高収率は，FSM-16のヘキサゴナル構造や高比表面積ではなくバルク層に導入されたクロム導入量に依存することが明らかになった．

Journal of Chemistry and Chemical Engineering


The Catalytic Conversion of 1,2-Propandiol to Propanal on FSM-16 Molded by Wet-Treatment and Pressurization

The catalytic conversion of 1,2-propandiol to propanal is examined using FSM-16 particles (0.85-1.75 mm) molded by wet-treatment and pressurization. When FSM-16 was molded with 0.6 g of pressurization and supplied to the catalytic conversion of 1,2-propandiol at 673 K, this system resulted in a 94.8% conversion of 1,2-propandiol and 90.5% selectivity to propanal at 0.25 h on-stream, which was the maximum amount of activity. However, at 4.50 h on-stream, the activity was decreased extremely to deactivation 19.9% conversion of 1,2-propandiol and 84.7% selectivity to propanal. In contrast, when FSM-16 molded with wettreatment (0.15 g) was used for the conversion at 573 K, activity was greatly increased and stable 98.6% conversion of 1,2-propandiol and 56.2% selectivity to propanal at 0.25 h on-stream followed by 91.9% and 52.5%, respectively, at 4.50 h on-stream. The hexagonal structure of FSM-16 was suggested to have contributed to the suitable conversion of 1,2-propandiol to propanal.

1,2-プロパンジオールからプロパナールへの接触変換を加圧成型したFSM-16(粒径0.85-1.75 mm)を0.6g用い673Kで行うと，通塔15分後には94.8%の変化率でプロパナールを90.5%の選択率で合成できたが，著しい活性劣化を示し，通塔4.5時間後には，変化率19.9%，選択率84.7%となった．一方湿式成型したFSM-16を0.15g用い反応を行うと，変化率98.6%選択率56.2%が通塔15分後に検出され，通塔4.5時間後まで維持された(それぞれ91.9,52.5%)．FSM-16中のヘキサゴナルな構造が維持されると安定した触媒活性が得られることが明らかになった．

Journal of Chemical Engineering of Japan


The Oxidative Esterification of Propionaldehyde to Methyl Propionate in the Liquid-phase Using a Heterogeneous Palladium Catalyst

The optimization of the oxidative esterification of propionaldehyde to methyl propionate using a supported palladium catalyst in methanol under heavy-metal-free and pressurized-oxygen conditions, which we recently reported in a previous paper, were carried out together with a study of the reaction route, the nature of the catalytic active sites, and the effect of the support. In our previous paper, we reported significantly improved activity for oxidative esterification using commercially available 5%Pd/Al2O3 at 1.5 MPa of O2 gas and 333 K and emphasized that the doping of 5%Pd/Al2O3 with lead was not needed for the reaction system, but we could not improve the activity that was reported when using 5%Pd/ -Al2O3 doped with 5% Pb (a 93.2% conversion of propionaldehyde, 76.8% selectivity for methyl propionate and a 71.6% yield of methyl propionate) at 0.3 MPa of O2 gas and 353 K, as reported by another laboratory. In the present study, however, we exceeded those values and obtained a 98.3% conversion of propionaldehyde, 75.3% selectivity for methyl propionate and a 74.0% yield of methyl propionate using 5%Pd/ -Al2O3 undoped with Pb at 1.5 MPa of O2 gas and 333 K. It should be noted that, in the preparation of the present 5%Pd/ -Al2O3, Pd was doped onto Al2O3 that had been previously treated with aqueous NaOH. Another active alumina support, -Al2O3, prepared from boehmite, afforded activity that was substantially lower than that of -Al2O3 and depended on the calcination temperature of boehmite to -Al2O3. When using various concentrations of CH3OH in the aqueous reaction solution, the oxidative esterification proceeded through the formation of propionic acid. To determine why Al2O3 support afforded better activity than active carbon support, Pd/Al2O3 and Pd/C catalysts were examined by XAFS (X-ray absorption fine structure). XAFS revealed that Pd on Al2O3 shows a better redox nature than Pd on C, which resulted in activity on Pd/Al2O3 that was better than that on Pd/C.

表題反応の最適化を重金属で修飾していないパラジウム触媒を用い酸素加圧下の条件下で行った．さらに反応機構，活性座についての検討，担体効果についても検討した．γーアルミナに担持したパラジウム触媒において，プロピオン酸メチルの収率が74%に達成し，市販品触媒の活性を上回った．ベーマイトから調整したη-アルミナを担体とした場合，上記の収率を超えることはできなかったが，ベーマイとの焼成温度に触媒活性は依存した．溶媒効果や関連化合物の反応挙動により，この反応に対してはプロピオン酸を経て進む反応機構が提案された．XAFSの検討から担体のレドックスが触媒活性に影響を与えていることが明らかになった．


Liquid-phase Oxidation of Propylene Glycol Using Heavy-metal-free Pd/C under Pressurized Oxygen

プロピレングリコールの酸化脱水素反応に対する触媒としてPd/Cが，酸素加圧下では1級および2級アルコールの酸化脱水素反応を良好に進行することを明らかにし，従来重金属で触媒を修飾する必要があるといわれていた触媒調製法に新たな面を明らかにした論文．


Recovery and Enrichment of Aqueous Phosphate from the Slag Released by a Chemical Factory

化学工場で廃棄されているスラグを酸で処理する湿式処理を行うと，良好にリン酸を溶出できることを示した．さらにこの溶出の際に他のカチオン成分が合わせて溶出するが，このカチオン成分はカルシウム水酸アパタイトにより簡便に取り除くことができることを示し，このスラグが枯渇資源リンの新資源になりうることを示した．


Preparation of Carbon-Supported Pt Catalysts Covered with Microporous Silica Layers Using Organosilanes: Sintering Resistance and Superior Catalytic Performance for Cyclohexane Dehydrogenation


Synthesis and Characterization of Surface-Functionalized Layered Titanate Nanosheets Using the Lamellar Self-Assembly as a Template


Direct Oxidative Esterification of Propionaldehyde to Methyl Propionate Using Heavy-metal-free Palladium Catalysts under Pressurized Oxygen

The use of pressurized oxygen greatly enhanced catalytic activity for oxidative esterification of propionaldehyde to methyl propionate with methanol using heavy-metal-free Pd/C and Pd/Al2O3. For example, the conversion of propionaldehyde, the selectivity to methyl propionate, and the yield of the propionate using 5 % Pd/Al2O3 were 99.9, 62.7, and 62.6 %, respectively, at 1.5 MPa of oxygen gas and 333 K. This result demonstrated that Pb doping of Pd catalysts was not needed to achieve comparable activity, which runs contrary to previous reports, in which it had been suggested that loading of Pd catalysts using a heavy metal such as Pb was needed for the great activity such as 93.2, 76.8, and 71.6 % of the conversion of propionaldehyde, the selectivity to methyl propionate, and the yield of the propionate, respectively, at 0.3 MPa of oxygen gas and 353 K using 5 % Pd/Al2O3 doped with 5 % Pb.

プロピオナルデヒドのプロピオン酸メチルの酸化的メチるエステル化に対する触媒としてPd/Al2O3をPbで修飾した触媒が高活性を示すと報告されていたが，酸素加圧を行うとPbでの修飾がなくても高活性を示すことを明らかにした論文．

Journal of the Japan Petroleum Institute


Hydroxyapatite Particle Characteristics Influence the Enhancement of the Mechanical and Chemical Properties of Conventional Restorative Glass Ionomer Cement

The aims of this study were to improve the mechanical and chemical properties of conventional restorative glass ionomer cement (GIC) by adding hydroxyapatite (HAp) preparations with different characteristics, and to investigate the underlying reaction mechanisms. Fuji IX GP® was used as the control GIC. The experimental GICs consisted of four HAp-particles with different characteristics added at 8 mass% to Fuji IX-powder. All cements were prepared by mixing with Fuji IX-liquid (P/L=3.6). Four HAp-particles were analyzed, and then the mechanical strengths and the fluoride-ion- release-recharge-behaviors of five GIC groups were evaluated. The results of this study demonstrate that the addition of HAp particles with highly reactive properties such as high specific surface area can enhance the flexural strength and fluoride ion release properties of conventional restorative GIC. Our results further indicate that HAp functions as an adsorbent and an ion exchangeable agent, resulting in improved mechanical and chemical properties of GIC.


Removal of Aqueous Ammonium from Seawater and Freshwater Using Magnesium Hydrogen Phosphate

魚飼育環境下で魚の致死原因物質をなるアンモニアを回収するため，水族館，養殖所，水産試験所から入手した海水と淡水からのアンモニア回収を，回収剤としてリン酸水素マグネシウムを用いて行った．中性領域でもアンモニアを回収することができ，実使用に対する知見が得られた．


Recovery of Phosphate from Unused Resources

枯渇資源リンの新資源開発のため，河川中からのリン回収を徳島の河川をモデルとして回収剤にベーマイトを用いて行い，河川中の不純物が回収効率に悪影響を与えないことを明らかにした．さらに，新資源として鉄鋼スラグからのリンの溶出実験を行い，硝酸などの酸を用いると良好に溶出できること，また溶出液に水酸化マグネシウムを添加すると固体としてリン化合物を析出させることができることを明らかにした．


Indentations and baffles for improving mixing rate in deep microchannel reactors


Catalytic Property of Carbon-Supported Pt Catalysts Covered with Organosilica Layers on Dehydrogenation of Organic Hydride

Studies in Surface Science and Catalysis


Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium

マイクロリアクタを用い，反応物の吸着を低温，吸着物の反応と生成物の脱離を高温で行う非定常操作を駆使すると，従来接触酸化脱水素反応の欠点とされていた深度酸化が抑えられるとともに，触媒量を1/1000に減らせることを明らかにした．2010年度Journal of Chemical Engineering of Japan誌のOutstanding Paper Awardをを受賞した．


Catalytic Conversion of Ethylene to Propylene over MCM-41

エチレンからプロピレンの接触変換反応をMCM-41とNiで改質したMCM-41で検討した．Niで改質しないとプロピレンは生成されず，Niで改質した触媒のプロピレン生成活性は触媒調製法と反応条件に強く依存した．カーボン析出のため長時間にわたる安定した活性は得られなかったが，水を共存させると，安定性とともに活性も向上することが明らかになった．

International Journal of Modern Physics B


Control of Morphology and Surface Property of Flaky Layered Titanate Nanosheets using Surfactant in Hydrothermal Solution


Application of Heavy-metal-free Pd/C Catalyst for the Oxidative Dehydrogenation of Sodium Lactate to Pyruvate in an Aqueous Phase under Pressurized Oxygen

従来乳酸からピルビン酸への酸化脱水素反応はNaOH水溶液でpHをアルカリに調整して，PbやTeで修飾したPd/Cを触媒としなければならないとされていた．本論文では，酸素加圧を用い，乳酸ナトリウムを用いるとアルカリの調整を必要とせず，また有害な重金属で修飾しないPd/Cで良好な酸化脱水素活性が現れることを明らかにした．


Ethanol Conversion on MCM-41 and FSM-16, and on Ni-Doped MCM-41 and FSM-16 Prepared without Hydrothermal Conditions

エタノールからエチレンおよびエタノールからプロピレンへの接触変換反応において，メソポラスシリカであるFSM-16とMCM-41およびそのNi修飾体を用いて活性の比較検討を行なった．現在まで注目されている触媒はMCM-41であるが，本研究の結果から，FSM-16の方が調製の際に水熱合成を必要としないにもかかわらず，非常に高い活性を示すことを明らかにした．


Tracing the Effects of the Propagation on Information on Engineering Carried out in the Faculty of Engineering, The University of Tokushima, on the Freshmen of the Faculty - From "Scinece Summer Festival in Tokushima" to "Engineering Festival" -

徳島大学工学部の工学啓蒙活動の新入学生への影響-科学体験フェスティバルin徳島∼エンジニアリングフェスティバルまで-

全国の大学では工学離れを防ぐため，様々な取り組みを行っているが，その具体的効果の検証を行った例はほとんどない．本論文では，徳島大学工学部が実施している工学啓蒙活動，具体的には，科学体験フェスティバルin徳島(幼児∼中学生対象)，工学体験大学講座(高校生対象)，オープンキャンパス(高校生対象)，出張講義(高校生対象)およびエンジニアリングフェスティバル(高校生∼社会人対象)の工学部新入生への影響をアンケート調査した結果についての検証を行った．大学の進路は，大学入試を具体的に考える高等学校在学時に決まるという認識が一般的である．本検証においても，高等学校在籍時に受けた上記の啓蒙活動が，本学工学部への入学に大きな影響を与えていることは認められた．しかしながら，小学校入学前後の比較的低年齢時に受けた啓蒙活動も，徳島大学工学部入学，さらには徳島から全国への理系進学に大きな影響を与えていることが明らかとなった．

Journal of University Education Research


Flow Uniformity in Deep Microchannel Reactor under High Throughput Conditions


Present Situation and Ripple Effects of "Scinece Summer Festival in Tokushima" Held to Aim to Avoid Moving Away from the Engineering

工学離れを防 ぐ''科学体験フェスティバル in 徳島''の現状と波及効果

平成20年度に第12回開催となった''科学体験フェスティバルin徳島''についての開催から現在までの経緯をまとめ，第12回大会の参加者のアンケート調査の結果と考察，また工学部新入学生への入学動機に対する本大会の波及効果を検証したものをまとめた．

Journal of Japanese Society for Engineering Education


Removal of Aqueous Ammonium from Industrial Wastewater with Magnesium Hydrogen Phosphate

鉄鋼業および発電施設から排出された廃液中のアンモニアを回収し，資源浄化を行うとともに，回収したアンモニアを再生して原料として使用するため，リン酸水素マグネシウムを回収剤とするプロセスの検討を，特に工業廃液からのアンモニアのい回収という点から検討を行った．実際の工業廃液を用いても十分に回収可能であることを明らかにした．


Preparation of a Hydroxyapatite Film and Its Application in the Removal and Regeneration of Aqueous Cations

Aqueous Pb2+, Cd2+, Co2+ and Cu2+ were continuously removed and regenerated using a bulk powder of calcium hydroxyapatite (Ca10(PO4)6(OH)2, CaHAp) and a glass plate coated with a thin film of CaHAp. Although use of CaHAp effectively removed aqueous Pb2+ from the wastewater, lead cations immobilized on CaHAp could not be regenerated in an aqueous solution due to formation of lead hydroxyapatite (Pb10(PO4)6(OH)2), which is insoluble in water at acidic and neutral pH. In contrast, Co2+ and Cu2+ immobilized on CaHAp were easily regenerated in an aqueous solution by treatment with an acidic aqueous solution containing Ca(NO3)2, as previously reported for the CaHAp-Cd2+ system. We found that the combination of the removal of the aqueous divalent cations by the CaHAp film and subsequent regeneration of the immobilized divalent cations from the film allowed for recycling of the film and for removal and regeneration of aqueous Cd2+, Co2+ and Cu2+.

カルシウム水酸アパタイト粉末およびこれをガラス基板にコ-ティングしたをものを用いて水溶性Pb2+, Cd2+, Co2+ and Cu2+の連続回収-再生を行った．Pb2+はカルシウム水酸アパタイトに固定化されると再生することができなかったが，他の水溶性カチオンは，連続回収-再生が可能であることが明らかとなった．従来は水溶性重金属の回収に使用した材料は破棄するしかなかったが，本研究はカルシウム水酸アパタイトと水溶性重金属の再利用ができることを示している．

Journal of Colloid and Interface Science


Application of the Unique Redox Properties of Magnesium ortho-Vanadate Incorporated with Palladium in the Unsteady-state Operation of the Oxidative Dehydrogenation of Propane

プロパンの酸化脱水素触媒としてマグネシウムオルトバナデートをパラジウムで修飾した触媒を見出した．パラジウムを導入すると，バナデートのレドックスを著しく加速でき，そのため初期活性が著しく改善した．レドックスの加速について，格子酸素については昇温還元，昇温酸化で確認を行い，格子酸素のカウンターカチオンのレドックスは，固体NMRやXAFSで明らかにした．触媒劣化が起こるが，非定常操作で劣化を抑えることができることを示した．


Dehydrogenation of Cycloalkanes over Noble Metal Catalysts Supported on Active Carbon

水素貯蔵媒体であるデカリン，テトラリン，ジシクロヘキシル，ファニルシクロヘキサンのPt/C，Pd/CおよびそのTe添加触媒の脱水素活性を検討した．これらの触媒の脱水素活性およびTeの添加効果は，反応基質の芳香属性に依存することが明らかになった．


Effects of Several Harmful Anions on the Removal of Aqueous Phosphate by Boehmite

ベーマイトによる水溶性リンの回収に対する炭酸塩，硫酸塩，硝酸塩，亜硝酸塩，塩素および「フッ素のアニオン共存効果を検討した．フッ素を共存させると水溶性リンとともに良好に回収されたが，他のアニオン共存効果は見られなかった．また市販品ベーマイトより本研究でゾルゲル法で調製したベーマイトのほうが高い回収活性を示した． 固体31P MAS NMR分析により，リンの回収形態にはpHやアニオン効果を受けたことにより2種類の形態が存在することが明らかになった．


Oxidative Dehydrogenation OF Propane on Vanadate Catalyst Supported on Various Metal Hydroxyapatites

バリウム水酸アパタイトへバナデートを担持した触媒を調製し，プロパンからプロピレンへの酸化脱水素触媒活性を検討した．バナデートとバリウム水酸アパタイト間の特異相互作用のため，触媒の格子酸素の移動度が抑制され，周期律表から予期される活性よりは低い触媒活性が現れることを明らかにした．このような特異相互作用は他の水酸アパタイトには見られないものであった．


Removal and Regeneration of Aqueous Divalent Cations by Boehmite

Boehmite (Al(OH)O) was employed for the removal of aqueous Mg2+, Cu2+, Cd2+, Pb2+, and Co2+ at 298 K. Although boehmite showed a certain removal nature of those divalent cations, the greater removal rate with boehmite of Pb2+ (28.7 %) than those of Mg2+, Cu2+, Cd2+, and Co2+ (5.6, 25.3, 10.9, and 13.3%, respectively) was observed in acidic conditions. Under stronger alkaline conditions, at which lead species was completely dissolved, rather greater removal rate of Pb2+ (more than 80%) was observed under the corresponding conditions employed for the acidic conditions. The removed lead species could not be dissolved from boehmite in an acidic solution while an evident dissolution of lead species was detected using aqueous NaOH solution. The results shown in the present study reveals that boehmite can be employed as a reagent for the removal and regeneration of aqueous metal cations.

ベーマイトを水溶性Mg2+, Cu2+, Cd2+, Pb2+, and Co2+の回収に適応し，回収効率がPb2+>Cu2+>Co2+>Cd2+>Mg2+であることを見出した．最も回収効率の高いPb2+の再生はNaOH溶液で達成できることを明らかにした．したがってベーマイトが水溶性金属の回収‐再生に適応できる可能性を明らかにした．


Forced temperature cycling of a catalyst layer and its application to propylene oxidation


Experimental Investigation on the Effect of Forced Temperature Cycling Operation on a Chemical Reaction

温度周期操作を利用した反応制御技術の実験的検討

The present study aims at developing a new chemical reactor for forced temperature cycling at a low energy cost. Forced temperature cycling is an attractive mode of chemical reactor operation, since it can achieve higher conversion and selectivity for a variety of chemical reactions than steady-state operations. However, there are only limited number of experimental investigation on the effects of forced temperature cycling on chemical reactions. This is because a large amount of energy is needed to quickly change the reactor temperature. With the reactor developed in this study, only 9 W of electric energy was required to achieve forced temperature cycling. In a sample case of the cycling operation for propylene oxidation, it was demonstrated experimentally that the selectivity and conversion can be controlled by employing the forced temperature cycling.

反応装置の温度を周期的に変化させると反応率，収率，選択率などの時間平均値が，定常状態での値を上回る可能性が数値計算による検討結果によって明らかにされている．しかし，温度周期操作が反応に及ぼす影響についての実験的な検討はほとんど行われていない．これは，温度周期操作には大量のエネルギーが必要とされるため実施がきわめて困難であるためである．本研究では従来とは異なる形式の反応装置を提案し，これを利用した温度周期操作について検討を行った．本研究で開発した反応装置は，ヒーターを反応流路の内部に設置している点で一般的な反応装置と異なる．開発した反応装置では約9 Wの電力で動作することが示された．プロピレンの酸化反応を例に取った反応実験を行ったところ，温度周期操作によって選択率を制御できる可能性が示された．


Fluid flow behavior and the rate of an enzyme reaction in deep microchannel reactor under high-throughput condition


Oxidative Dehydrogenation of Propane over Vanadate Catalysts Supported-on Calcium and Strontium Hydroxyapatites

プロパンからプロピレンへの酸化脱水素触媒に対してカルシウムおよびストロンチウムヒドロキシアパタイト触媒は高い活性を示さないが，バナデートを担持すると，従来非常に高い活性を示すといわれていたマグネシウムピロバナデートに匹敵する高い活性を示すことを見出した．バナデートのレッドクス挙動が活性の向上に直接影響を与えていることを，固体51V MAS NMRなどを用いて明らかにした．

Journal of the Japan Petroleum Institute


Redox Nature of Fe-incorporated Magnesium ortho-Vanadate as a Catalyst for the Oxidative Dehydrogenation of Propane

プロパンの酸化脱水素触媒であるバナジン酸オルトバナデートの触媒活性を改善するため様々な一価，二価，三価金属をこの触媒に導入したところ，鉄を添加した触媒の活性が改善された．鉄の導入によって格子酸素のレドックス挙動が直接影響を受け，触媒活性が改善されることを，様々な条件での触媒活性試験とともに，51V MAS NMR，XAFS，XRDなどを用いて明らかにした．

Journal of Chemical Engineering of Japan


51V MAS NMR and XAFS Evidences for Redox of Magnesium pyro- and ortho-Vanadates on the Oxidative Dehydrogenation of Propane

プロパンの酸化脱水素触媒に高活性を示すマグネシウムピロバナデートとマグネシウムオルトバナデートのレッドクス挙動を51V MAS NMRやXAFSを用いて明確に示した．ピロバナデートはレドックスが激しいため通常の条件では高活性を示すが，一度還元すると元に戻らない一方，オルトバナデートのレドックスは穏やかなため，活性は低いが安定した触媒であることを示した．


Removal-Regeneration of Aqueous Phosphate with Bulk and Thin-Layer Boehmite

ベーマイトによる水溶性リンの回収-再生に関する研究を行った．ベーマイトをゾル-ゲル法で調製すると高表面積のため回収率が，市販品のものより高くなるが，あまり表面積を上げすぎると，ベーマイトが解こうし，不都合であることが見出された．ゾル-ゲル法で調製したベーマイトゾルをディップコーティング法でガラス基板上に製膜すると，リンの回収を行えると共に，回収したリンを容易に脱離-回収できることを見出した．


Droplet Formation by the Collision of Two Aqueous Solutions in a Microchannel and Application to Particle Synthesis


Preparation Procedure of Barium Hydroxyapatite with Sol Contaninig of Sodium Alginate and Sodium Diphosphate

バリウム水酸アパタイトの薄膜調製へ展開可能な調製法として，ゾル化試薬としてアルギン酸ナトリウムを用いるゾルゲル法を検討した．カルシウム水酸アパタイトに報告されている処方を改善し，試薬の混合の順を変えると，良好に調製できることを明らかにした．


Effects of Incorporation Procedure of Titanium Cations into Calcium Hydroxyapatites on the Photo-Catalytic Activities for the Decomposition of Methylene Blue

カルシウム水酸アパタイトへ段階的沈殿法，共沈法，表面改質法でチタンを導入し，導入した触媒のメチレンブルー光分解に対する触媒活性を検討した．表面改質した触媒では活性はほとんど観測されない．共沈法で調製した触媒の活性が最も高く，その活性は触媒中のチタンとカルシウムの比に依存することを明らかにした．


Enhancement of the Activity for Oxidative Dehydrogenation of Propane on Calcium Hydroxyapatite Substituted with Vanadate

カルシウム水酸アパタイトにバナジウムを置換して導入するとプロパンの高活性酸化脱水素触媒であるメター，ピローおよびオルトーバナジン酸マグネシウムの触媒活性を超えることを見出した．バナジウムの5価と4価間のレドックス作用がカルシウム水酸アパタイトの酸化脱水素触媒活性と相乗作用を起こし，高活性を示すことを，固体V MAS NMRなどを用いて明らかにした．


Formation of Hydroxyapatite-layer on Glass-plate and its Removal-regeneration Properties of Aqueous Cadmium

カルシウム水酸アパタイト薄膜を形成する際，原料を硝酸カルシウム，リン酸水素アンモニウムとし，溶媒をエタノール-水とするとディップコティング法を用いることにより，400℃程度の低温度焼成で薄膜形成ができることを明らかにした．さらに，調製した薄膜を用い，水溶性カドミウムの回収-脱離が可能であることを，これまで報告されていない新規の方法で達成できることを明らかにした．

Journal of Colloid and Interface Science


Stability of Protease in Organic Solvent: Structural Identification by Solid-state NMR of Lyophilized Papain before and after 1-Propanol Treatment and the Corresponding Enzymatic Activities

有機溶媒中で酵素反応を行うと，時間の経過に伴い活性が低下する場合がある．本研究では，酵素パパインの構造を13C cross-polarization/magic angle sppining および円偏光二色性により解析し，触媒活性と構造変化との相関性を検討した．パパインをプロピルエステル化反応に用いると，酵素再利用時に活性が著しく減少した．13C-MAS NMRの結果，反応前に比べてα-ヘリックス/β構造の比が減少することがわかり，この構造変化が活性の減少につながっていることを明らかにした．


Material Balance and Energy Consumption for CO2 Recovery from Moist Flue Gas Employing K2CO3-on-Activated Carbon and Its Evaluation for Practical Adaption

湿性煙道ガス中のCO2除去-放出に，活性炭担持炭酸カルシウムを用いた．温度を変化させるだけでCO2の除去-回収ができることを示し，ベンチスケール実験も行った．その結果を，従来検討されているシステムを比較検討し，本プロセスの有効性を示した．


Preparation of Alkaline Earth Phosphates with Sol Containing of Sodium Alginate and Sodium Diphosphate

機能性材料として有望なリン酸水素マグネシウム，カルシウム水酸アパタイト，ストロンチウム水酸アパタイトの薄膜調製法として，ゾル化試薬としてアルギン酸ナトリウムを用いる方法を開発した．従来，カルシウム水酸アパタイトについては，アルギン酸ナトリウムを用いると調製できると報告されていたが，それらの報告に従うとカルシウム塩素アパタイトが形成されることを示し，新たな調製法を見出した．またこの手法を，リン酸水素マグネシウムやストロンチウム水酸アパタイトの調製に応用し，双方のリン酸化合物に最適な調製法を見出した．


Employment of 31P MAS NMR for the Identification of Amorphous Precipitation Products Obtained from MAP Process

マグネシアと塩化マグネシウムによって水溶性リン酸およびアンモニアの同時除去を行い，その生成物の構造決定を固体NMRで行った．上記の除去法はMAPプロセスとよばれ，除去後にはマグネシウムアンモニウムホスフェート(MAP)という難溶性の物質となり，固定化除去されると言われていた．MAPは遅効性肥料として有効であるが，現場からはその肥料としての安定性が無いことが指摘されていた．本研究で固体31P MAS NMRを用いて分析したところ，MAP以外に多くのリン酸塩が形成されており，そのために品質が安定しないことを明らかにした．

Bulletin of the Chemical Society of Japan


Effect of Support and Liquid-film Conditions on Dehydrogenation of Decalin by Platinum Catalysts

デカリンの脱水素白金触媒への担体の効果と液膜条件

活担体としてデカリンと親和性の良い活性炭を用いると過熱液膜条件を示すが，親和性の悪いアルミナおよびベーマイトを担体に用いると過熱液膜条件が確認できなかった．さらに，Pt/C触媒を用いて過熱液膜条件への温度効果の検討，反応系内に多く存在する物質の沸点よって，過熱液膜条件達成への最適外部加熱温度が変化し，従来のような，一定の反応基質/触媒比および特異な反応温度で過熱液膜条件が定義されないことを明らかにした．

Journal of the Hydrogen Energy Systems Society of Japan


Removal of Aqueous Ammonium with Magnesium Phosphates Obtained from the Ammonium-Elimination of Magnesium Ammonium Phosphate

水質汚染の元凶である水溶性リン酸，アンモニウムを回収した際に生成するアンモニウムマグネシウムフォスヘート(MAP)を，水質改善材料として再利用するため，MAPの熱分解挙動，熱分解で生成した化合物の同定とアンモニア回収への再利用を検討した．熱分解生成物には様々な化合物が提案されていたがリン酸1水素マグネシウムであることを固体NMRで明らかにした．また，熱分解生成物を水溶性アンモニウムの回収に利用できることを明らかにした．


Bench-Scale CO2 Recovery from Moist Flue Gases by Various Alkali Carbonates Supported on Activated Carbon

湿性ガスから二酸化炭素を回収除去するため，活性炭担持アルカリ金属炭酸塩が検討された．313 – 393 Kにおいて二酸化炭素は除去され，その除去の序列はNa2CO3 < K2CO3 < Rb2CO3 ~ Cs2CO3であった．これらの回収剤を用いてベンチスケールで実験を行い，二酸化炭素除去効率は313-392Kにおいて，通常の二酸化炭素回収法であるアミン吸収法より有利であることを示した．

Journal of Chemical Engineering of Japan


Catalytic Activity of Iron Oxides Supported on γ-Al2O3 for Methane Oxidation

Three kinds of catalysts of goethites supported on γ-Al2O3 (Fe/γ-Al2O3), SiO2-Al2O3 (Fe/SiO2-Al2O3) and SiO2 (Fe/SiO2) were investigated in terms of the catalytic activity of methane oxidation. The specific surface areas of these catalysts were larger in common than the area of goethite with no supports. The Fe/γ-Al2O3 catalyst has the highest performance in the low-temperature activity of methane oxidation which started at 623 K and completed at 923 K. When the Fe-content in Fe/γ-Al2O3 was increased, the formation of goethite was observed by the X-ray analyses and the activity of this catalyst increased up to 6 mol%. After the catalytic methane oxidation at 823 K, it was observed that goethite in Fe/γ-Al2O3 transformed to hematite which has been known as an active iron oxide in methane oxidation. The activity of Fe/γ-Al2O3 was enhanced by the addition of sodium up to the Na-content of 5 mol% although it descended above the content due to the decrease of the specific surface area of the catalyst.

Journal of the Japan Petroleum Institute


Effects of the Enhancement of the Abstraction of Lattice Oxygen from Magnesium Vanadates Incorporated with Copper (II) Cations on the Oxidative Dehydrogenation of Propane

プロパンの高活性酸化脱水素触媒バナジン酸マグネシウムへ銅カチオンを添加し触媒活性，格子酸素移動度を検討した．レドックスを起こしやすい銅を添加したため，格子酸素の移動度が増大し，プロピレンへの部分酸化が抑制され，二酸化炭素への完全酸化が進行した．銅カチオンが還元されやすいことが完全参加につながったため，還元されにくいカチオンの添加が効果的であろうということを示した．

Journal of Molecular Catalysis A: Chemical


Immobilization of Aqueous Tetravalent Cations of Titanium and Zirconium with Calcium Hydroxyapatite

最近高い光触媒活性を示すことが報告されたチタンアパタイトの合成処方を検討した．既報のチタンアパタイト調製法では共沈法が採用されていたが，その処方では共沈とはならないことを明らかにした．そして，正しい共沈処方を示すとともに表面改質法によるアパタイトのチタン修飾法を報告した．またチタンと同様に4価であり光触媒機能を持つジルコニアについても表面改質の検討を行い，将来の光触媒として可能性のあるチタンおよびジルコニアアパタイトの調製法を明確にした．

Colloids and Surfaces A:Physicochemical and Engineering Aspects


Steam Reforming of n-Dodecane over Ru/Al2O3 catalyst and estimation method of the gas composition formed

Ru/Al2O3触媒によるn-ドデカンの水蒸気改質実験とその生成ガス組成の推定方法

Ru系触媒を用いて灯油の代表成分であるn-ドデカンの水蒸気改質を行ない，反応温度やS/C比などの反応条件が生成ガス組成に及ぼす影響を調べるとともに，熱力学的な平衡計算により生成ガス組成を推定する方法を検討した．また，長時間連続の改質試験にける反応系での物質収支から求めたn-ドデカンや改質用の水の反応率について考察した．

Journal of the Hydrogen Energy Systems Society of Japan


K2CO3担持活性炭の固定床による湿性ガスからのCO2回収のベンチスケール試験

K2CO3担持活性炭の固定床による湿性ガスからのCO2回収のベンチスケール試験

炭酸カリウム担持活性炭 1.2 kgを充填したカラムに湿性13%二酸化炭素ガスを通気して二酸化炭素を捕捉した後，蒸気を通じて二酸化炭素を脱離するベンチスケールでの二酸化炭素捕捉-脱離および冷却挙動を明らかにした．また二酸化炭素回収時のエネルギー消費量を推定した．


Effects of Calcium Cations Incorporated into Magnesium Vanadates on the Redox Behaviors and the Catalytic Activities for the Oxidative Dehydrogenation of Propane

プロパンの高活性酸化脱水素触媒であるメター，ピローおよびオルトーバナジン酸マグネシウムのマグネシウムを一部カルシウムに置換した触媒を合成し，触媒活性，格子酸素の移動度を検討した．カルシウムの置換による触媒活性および格子酸素の移動度への影響は3種類の触媒によって全く異なることが明らかになった．つまりカルシウム置換バナジン酸マグネシウムの2価カチオンが直接格子酸素へ影響を与えていることが明らかになった．


Local Structure around Platinum in Pt/C Catalysts Employed for Liquid-phase Dehydrogenation of Decalin in the Liquid-film State under Reactive Distillation Conditions

水素輸送媒体デカリンからの加熱液膜条件における脱水素反応に高活性を示すPt/Cの白金周りの微細構造がEXAFSで検討された．0価の金属状態にある白金は低活性を示すのに対し，共有結合性の白金が高活性を与えることを明らかにした．担体の塩基処理，白金の還元処理が脱水素触媒活性に大きな影響を与えた．


Immobilization of Aqueous Heavy Metal Cations with Phosphates and Sulfates

リン酸一水素ナトリウム，カリウム，マグネシウムおよびカルシウムを用いると，鉛，カドミウム，コバルトおよび銅の2価カチオンを含んだ水溶液から短時間でこれら重金属カチオンを固定化回収できることが明らかにした．また硫酸マグネシウムおよびカルシウムを用いても水溶性鉛の固定化回収ができることを見出し，このような固定化能はカルシムヒドロキシアパタイトに限定されていたが，様々な化合物への展開の可能性を示した．

Bulletin of the Chemical Society of Japan


Effects of Preparation Procedures of Calcium-lead Hydroxyapatites on Thermal Stabilities and Catalytic Activities for Oxidative Coupling of Methane

二元系のカルシウム-鉛ヒドロキシアパタイトが，(A):酢酸カルシウム，酢酸カルシウムおよびリン酸水素2ナトリウムから共沈法，(B):カルシウムヒドロキシアパタイトの水溶性鉛による表面改質，および(C)カルシウムヒドロキシアパタイトと鉛ヒドロキシアパタイトの混練法の3手法から合成された．合成した二元系カルシウム-鉛ヒドロキシアパタイトの熱安定性，メタンの酸化カップリング活性は触媒調製法に大きく依存し，混練法から得られた触媒の活性が最も高かった．


Preparation of Boehmite Sol Employed for Formation of Alumina-Layer over Various Plates with the Dip-Coating

アルミニウムイソプロポキサイドの加水分解で得られるベーマイトゾルの形成挙動を検討したところ，加水分解時間は1時間という短い時間でも十分であるが，ベーマイトの焼成から得られるアルミナのシンタリングを防ぐには，24時間程度の加水分解時間が必要であることを明らかにした．またベーマイトから得られるアルミナ膜は，最近何の検討も無くガンマー体と言われてきたが，イーター体の可能性も考えるべきとの結果を示した．またベーマイトを形成させる薄膜基板としてガラスやステンレスなどの伝熱性の異なる基板も十分使用可能であることを示した．

Journal of Chemical Engineering of Japan


Role of Hydroxide Groups in Hydroxyapatite Catalysts for the Oxidative Dehydrogenation of Alkanes

水酸アパタイトのアルカンの酸化脱水素に対する触媒活性点を明かにするため，ストロンチウム水酸アパタイトの水酸基の水素の重水素化挙動を検討し，その結果をコバルトーストロンチウム水酸アパタイトの重水素化能とアルカンの脱水素酸化能と相関させた．水酸アパタイトの重水素化は反応温度が高いほど大きいことが固体プロトンNMRで明かになった．重水素化に相応しい反応温度がアルカン特にプロパンの酸化脱水素反応の反応温度と同程度であったので，容易に比較できることが分かった．その結果，コバルトストロンチウム水酸アパタイトの重水素化能が高いほど，酸化脱水素活性が高いことが明かとなった．つまりアルカンの酸化脱水素には水酸アパタイトの水酸基から水素がはずれた酸素化学種が直接影響していることが明らかになった．

International Journal of Modern Physics B


Heavy Metal Immobilization in Aqueous Solution Using Calcium Phosphate and Calcium Hydrogen Phosphates

リン酸カルシウムおよびリン酸水素カルシウムによる水溶性重金属の回収挙動を報告した．水溶性重金属の回収体として知られているカルシウムヒドロキシアパタイトの回収機構によるとアパタイト以外もリン酸塩も回収剤として可能性があることを示している．しかし，アパタイト以外の回収剤の検討を行った例が無かった．本研究でアパタイトよりも溶解度の高いリン酸塩を用いたところアパタイトを超える回収能があることが分かった．

Journal of Colloid and Interface Science


Enhancement of the Catalytic Activities in Propane Oxidation and H-D Exchangeability of Hydroxyl Groups by the Incorporation with Cobalt into Strontium Hydroxyapatite

ストロンチウムヒドロキシアパタイトにコバルトカチオンを添加すると，コバルト含有量の増加に伴ってプロパンの酸化活性およびアパタイト中の水酸基プロトンのH-D交換活性が増加した．従って，水酸基が外れて生じる裸の酸素化学種が活性種であることを結論付けた．また通常の手法で構造解析ができなかったコバルトを含有した触媒をXRD,固体NMR,XAFSで解析し，固溶体のヒドロキシアパタイトとしてコバルトが配置されていることを明らかにした．


Effects of Redox of Cu-Species in Copper-Strontium Hydroxyapatites on the Oxidative Dehydrogenation of Propane

プロパンの脱水素酸化反応において四塩化炭素存在下ヒドロキシアパタイトを触媒として反応した場合，活性が激減する．しかし，銅で修飾したストロンチウムヒドロキシアパタイトはプロピレンの収率が著しく改善されることを見出した．銅化合物の特異なレドックス挙動がこのような改善挙動を導き出していることをXAFSなどの測定を行い明かにした．


Structural Property and Activity for Methane Oxidation of Iron Oxides Prepared by NaOH and FeSO4 Solution

硫酸鉄水溶液と水酸化ナトリウム水溶液を混合することにより酸化鉄触媒を合成した．オキシ水酸化鉄であるゲータイトは混合比が酸性側である1.9以下あるいはアルカリ性側である2.6以上で生成した．酸性側のゲータイトは結晶性が悪く比表面積が低いにもかかわらずメタン酸化活性は低く，これはゲータイト中に残存する硫酸イオンに由来することを示した．


Oxidative Coupling of Methane on Calcium-lead and Barium-lead Hydroxyapatites

カルシウム-鉛およびバリウム-鉛ヒドロキシアパタイト触媒によるメタンの酸化カップリング反応を検討した．構成触媒のカルシウム，バリウムおよび鉛ヒドロキシアパタイトにはカップリング反応に対する触媒活性が無いにもかかわらず，前者2種類の触媒を鉛で修飾した触媒は高活性を示した．各構成触媒の熱安定性が触媒活性に影響を与えていることを示した．


Effect of Calcination and Sieving of Calcium Hydroxyapatite on Ion-exchangeability with Lead Cation in the Presence and Absence of HCl

カルシウムヒドロキシアパタイトの鉛のカチオン交換挙動が，アパタイトの焼成温度や篩い分け系に大きな影響を受けることを示した．特に塩酸存在下では，カチオン交換が促進されることが通説になっていたが，この促進作用が上記の因子の影響で逆に抑制されることを明らかにした．


Effects of Sulfate Ion on Crystal Structure and Activity for Methane Oxidation of Iron Oxide Prepared from Goethite

ゲータイトから調製した酸化鉄の結晶構造とメタン酸化活性に及ぼす硫酸イオンの影響

ゲータイトを前駆体として合成した酸化鉄を用いてメタン酸化活性試験を行った．酸化鉄によるメタン酸化活性は硫酸イオンの存在で抑制されることを明らかにした．この活性の低下は鉄原子に電子を供与して鉄の酸化力を減少させることにより引き起こされるが，同時に硫酸イオンは酸化鉄中に多くの酸素欠陥を酸化鉄格子中に導入するので，硫酸イオンが脱離するような550℃以上の高温では逆に活性が向上することを見いだした．


Oxidative Dehydrogenation of Propane on Magnesium Vanadates in the Presence of Tetrachloromethane

プロパンからプロピレンへの高活性酸化脱水素触媒であるマグネシウムバナデート触媒の触媒活性に対する四塩化炭素の添加効果を検討した．四塩化炭素の添加によって，表題触媒の活性を著しく改善できた．四塩化炭素が触媒からの格子酸素の引きぬきをコントロールし，触媒活性の改善を導いていることを示した．

Bulletin of the Chemical Society of Japan


31P MAS-NMR Evidence of Formation of Solid-Solution-Type Apatite from Ion-Exchange of Strontium Hydroxyapatite with Copper(II) Ion

ストロンチウムヒドロキシアパタイトと銅(II)イオンとのイオン交換でできる銅‐ストロンチウムヒドロキシアパタイトの構造は，銅ヒドロキシアパタイトとストロンチウムヒドロキシアパタイトの相分離した形ではなく，ストロンチウムヒドロキシアパタイトのストロンチウムが銅と同形置換した固溶体の形であることを固体NMRを用いて明らかにした．


Enhancement of Lead-Barium Exchangeability of Barium Hydroxyapatite

In order to improve lead-barium exchangeability of barium hydroxyapatite (BaHAp), the effects of the recycle employment of BaHAp and the introduction of HCl into the exchange solution have been investigated at 293 K. The ion exchange capacity of BaHAp was evidently improved by use of the recycle experiments to reach levels approximately twice that obtained via the batch experiment. XPS analyses revealed that the ion exchange appears to proceed from the surface to the bulk of the apatite. The addition of HCl to the exchange solution also resulted in the enhancement of the ion exchangeability of BaHAp. Based on the apparent solubility of BaHAp, which was estimated from the dissolution of BaHAp for 4 h, together with the results of that experiment, it is suggested that the dissolution-precipitation mechanism appears to be possible for ion exchange. Copyright 2001 Academic Press.

バリウムヒドロキシアパタイトと鉛のイオン交換能が，アパタイトを再使用する手法と塩酸を共存させる条件で改善されることを示した．このイオン交換挙動とSEM/EPMA，XPSなどの分析結果よし，イオン交換は表面から溶解-沈積機構で進行する事を明らかにした．

Journal of Colloid and Interface Science


Effects of Gas- and Solid-Phase Additives on Oxidative Dehydrogenation of Propane on Strontium and Barium Hydroxyapatites

ストロンチウムおよびバリウムヒドロキシアパタイトのプロパンの脱水素反応によるプロピレン生成の触媒活性を改善させるため，気相添加物として四塩化炭素，また固相添加物として銅および鉛をイオン交換で導入したところ，銅導入触媒を用い四塩化炭素を導入すると脱水素酸化活性が著しく改善されることを明らかにした．


Nitrous Oxide as Oxidant for the Oxidation of Methane on Barium Hydroxyapatites in the Presence and Absence of Tetrachloromethane

バリウムヒドロキシアパタイトを触媒としたメタンの酸化反応の酸化剤としてN2Oを用いたところ，気相中に微量の四塩化炭素を存在させると，他のアルカリ土類酸化物触媒が一酸化炭素を選択的に与えるのに反し，カップリング生成物の選択率が著しく改善されることを見出した．

Journal of Molecular Catalysis A: Chemical


Characterization of Calcium, Strontium, Barium and Lead Hydroxyapatites: X-ray Diffraction, Photoelectron, Extended X-ray Absorption Fine Structure and MAS NMR Spectroscopies

カルシウム，ストロンチウム，バリウムおよび鉛ヒドロキシアパタイトを固体材料の先端分析技術であるX線回折法，X線光電子分光分析，広域X線吸収微細構造分析および固体NMRを用いて分析し，特異なアパタイト構造の解析には先端分析技術の採用が不可欠であることを示した．


In Situ XRD and In Situ IR Spectroscopic Analyses of Structural Change of Goethite in Methane Oxidation

含水酸化鉄の一種であるゲータイトのメタン酸化活性について調べた．ゲータイトは針状結晶であるが，220∼230℃付近で脱水により比表面積の非常に大きい酸化鉄であるヘマタイトに相変態をすること，その比表面積の大きいヘマタイトがメタン酸化に大きく関わっていることをその場観察X線回折およびその場観察赤外分光法により明らかにした．


Vanadyl Hydrogenphosphate Sesquihydrate as a Precursor for Preparation of (VO)2P2O7 and Cobalt-incorporated Catalysts

ブタンから無水マレイン酸を高収率であたえる(VO)2P2O7を新規に合成した4価バナジウムからなるVOHPO4·1.5H2Oから合成できることを示した．さらに，VOHPO4·1.5H2Oにコバルトをインターカレートできることを示し，この触媒がブタン酸化活性に著しく高い活性を示した．


Reductive Decomposition of Trace Amount of Nitrates and Nitrites in Aqueous Phase

微量の硝酸性および亜硝酸性窒素の湿式還元分解

飲料水レベルの微量硝酸性および亜硝酸性窒素の湿式還元分解の触媒研究を行い，室温，常圧水素という温和な条件で処理できることを明らかにした．硝酸性窒素の分解には，銅過剰域の銅-パラジウム-炭素が高活性を示し，亜硝酸性窒素の分解にはパラジウム-炭素触媒が高活性を示した．


Sorption and Ion-exchange Properties of Barium Hydroxyapatite with Divalent Cations

バリウムヒドロキシアパタイトと種々の2価金属カチオンとのカチオン交換を検討し，銅と特異的にカチオン交換することを見出した．また，塩酸中でこのカチオン交換を行うと，交換速度が速くなり，この加速効果にはバリウムヒドロキシアパタイトの溶解挙動が影響していることを明らかにした．

Colloids and Surfaces A:Physicochemical and Engineering Aspects