The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Keiichi Tomishige - One of the best experts on this subject based on the ideXlab platform.
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development of a ru c catalyst for glycerol hydrogenolysis in combinatIon with an Ion Exchange Resin
Applied Catalysis A-general, 2007Co-Authors: Tomohisa Miyazawa, Kimio Kunimori, Shuichi Koso, Keiichi TomishigeAbstract:Abstract The combinatIon of Ru/C and Amberlyst Ion-Exchange Resin is effective for the dehydratIon and hydrogenatIon (denoted as hydrogenolysis) of glycerol to 1,2-propanediol under mild reactIon conditIons (393 K). A Ru/C catalyst prepared by using active carbon with a low surface area (∼250 m2/g) showed better performance than that prepared by using active carbon with a high surface area. In additIon, treatment of Ru/C catalysts prepared from Ru(NO)(NO3)3 with Ar flowing at the appropriate temperature enhanced the performance compared to that of the commercially available Ru/C catalysts. This temperature treatment can be influenced by the decompositIon of Ru precursor salt and aggregatIon of Ru metal particles. In additIon, the degradatIon reactIon as a side-reactIon to C1 and C2 compounds of glycerol hydrogenolysis was more structure-sensitive than the hydrogenolysis reactIon, and the selectivity of hydrogenolysis was lower on smaller Ru particles. The combinatIon of Ru/C with the Amberlyst Resin enhanced the turnover frequency of 1,2-propanediol formatIon drastically, and this indicates that 1,2-propanediol can be formed mainly by dehydratIon of glycerol to acetol catalyzed by Amberlyst and subsequent hydrogenatIon of acetol to 1,2-propanediol catalyzed by Ru/C.
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glycerol conversIon in the aqueous solutIon under hydrogen over ru c an Ion Exchange Resin and its reactIon mechanism
Journal of Catalysis, 2006Co-Authors: Tomohisa Miyazawa, Yohei Kusunoki, Kimio Kunimori, Keiichi TomishigeAbstract:Abstract Of the various noble metals (Ru/C, Rh/C, Pt/C, and Pd/C) and acid catalysts [an Ion-Exchange Resin (Amberlyst), H2SO4(aq), and HCl(aq)], the combinatIon of Ru/C with Amberlyst is effective in the dehydratIon + hydrogenatIon (i.e., hydrogenolysis) of glycerol under mild reactIon conditIons (393 K, 8.0 MPa). The dehydratIon of glycerol to acetol is catalyzed by the acid catalysts. The subsequent hydrogenatIon of acetol on the metal catalysts gives 1,2-propanediol. The activity of the metal catalyst + Amberlyst in glycerol hydrogenolysis can be related to that of acetol hydrogenatIon over the metal catalysts. Regarding acid catalysts, H2SO4(aq) shows lower glycerol dehydratIon activity than Amberlyst, and HCl(aq) strongly decreases the activity of acetol hydrogenatIon on Ru/C. In additIon, the OH group on Ru/C can also catalyze the dehydratIon of glycerol to 3-hydroxypropIonaldehyde, which can then be converted to 1,3-propanediol through subsequent hydrogenatIon and other degradatIon products.
Philip C Singer - One of the best experts on this subject based on the ideXlab platform.
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bench scale testing of a magnetic Ion Exchange Resin for removal of disinfectIon by product precursors
Water Research, 2005Co-Authors: Treavor H Boyer, Philip C SingerAbstract:Abstract The objective of this research was to compare enhanced coagulatIon with anIon Exchange for removal of disinfectIon by-product (DBP) precursors (i.e. natural organic matter (NOM) and bromide). Treatment with a magnetic Ion Exchange Resin (MIEX®) was the primary focus of this study. Raw waters from four utilities in California were evaluated. The waters had low turbidity, low to moderate organic carbon concentratIons, a wide range of alkalinities, and moderate to high bromide Ion concentratIons. The treated waters were compared based on removal of ultraviolet (UV) absorbance, dissolved organic carbon (DOC), trihalomethane formatIon potential (THMFP), and haloacetic acid formatIon potential (HAAFP). The results indicated that treatment with MIEX is more effective than coagulatIon at removing UV-absorbing substances and DOC. Treatment with MIEX and treatment with MIEX followed by coagulatIon yielded similar results, suggesting that coagulatIon of MIEX-treated water does not provide additIonal removal of organic carbon. MIEX treatment reduced the THMFP and HAAFP in all waters, and did so to a greater extent than coagulatIon. Treatment with MIEX was most effective in raw waters having a high specific UV absorbance and a low anIonic strength. Following MIEX treatment, subsequent chlorinatIon resulted in a shift to the more brominated THM and HAA species as compared to chlorinatIon of the raw water. MIEX also removed bromide to varying degrees, depending on the raw water alkalinity and initial bromide Ion concentratIon.
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impact of a magnetic Ion Exchange Resin on ozone demand and bromate formatIon during drinking water treatment
Water Research, 2004Co-Authors: Clayton J Johnson, Philip C SingerAbstract:The objective of this research was to examine the impact of a magnetic Ion Exchange Resin (MIEX) on ozone demand and bromate formatIon in two different ozonated waters at bench scale. The first raw water had a high bromide Ion concentratIon, a high ozone demand, and was highly colored. Based on experimental findings from the first water, the second water was selected as a model water in which more controlled experiments were performed. The waters were treated with the MIEX Resin using jar test procedures to find the optimal MIEX dosage based upon the removal of ultraviolet (UV)-absorbing substances, dissolved organic carbon (DOC), and bromide. The optimal Resin dosage was chosen for bulk MIEX treatment and subsequent ozonatIon in a semi-batch reactor. The ozone demand and formatIon of bromate were analyzed as a functIon of ozone dosage and dissolved ozone concentratIon for the MIEX pre-treated water, and compared to the results obtained by ozonating the water without MIEX pre-treatment. The results indicate that pre-treatment of the water with the MIEX Resin significantly reduces total organic carbon, DOC, UV absorbance, color, and to some extent, bromide. MIEX pre-treatment of the water prior to ozonatIon substantially lowered the ozone demand and formatIon of bromate during subsequent ozonatIon.
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enhanced coagulatIon using a magnetic Ion Exchange Resin
Water Research, 2002Co-Authors: Philip C Singer, Katya BilykAbstract:The objective of this investigatIon was to examine the effectiveness of a magnetic Ion Exchange Resin (MIEX) to enhance the coagulatIon of disinfectIon by-product precursors in nine surface waters, each representing a different element of the USEPA's 3 x 3 enhanced coagulatIon matrix. The effect of MIEX-pretreatment on the requisite alum dose needed for subsequent coagulatIon of turbidity was also evaluated. Enhanced coagulatIon with MIEX was found to be very effective for removing trihalomethane (THM) and haloacetic acid (HAA) precursors from the nine waters examined. THM and HAA formatIon potential was reduced by more than 60% in all of the waters studied; reductIons approaching 90% were seen in the waters with the highest specific ultraviolet absorbance values. The residual total organic carbon concentratIon, ultraviolet absorbance, and THM and HAA formatIon potential were all substantially lower as a result of MIEX and alum treatment compared to alum coagulatIon alone. MIEX pre-treatment also lowered the coagulant demand of each of the waters substantially.
David Scotter - One of the best experts on this subject based on the ideXlab platform.
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In situ Ion Exchange Resin membrane (IEM) technique to measure soil mineral nitrogen dynamics in grazed pastures
Biology and Fertility of Soils, 2008Co-Authors: Saman Bowatte, Russell Tillman, Andrew Carran, Allan Gillingham, David ScotterAbstract:This paper explored the potential of applicatIon of in situ Ion Exchange Resin membrane (IEM) technique for assessing soil nitrogen (N) availability and spatial distributIon in New Zealand grazed pastures. Field and incubatIon experiments conducted to test the technique proved IEM technique to be a useful approach to monitoring the continuous changes in soil mineral N in pasture soils. The field testing showed that the IEM technique reflects both differences in pool size and mineral N flux, while 2-M KCl extractIon reflects only pool size at the sampling. Testing the effects of residence time, temperature, soil inorganic N content, and soil water content through diffusIon modeling offers further support for using IEM to explore the complex dynamics of nitrogen availability in pasture soils.
Tomohisa Miyazawa - One of the best experts on this subject based on the ideXlab platform.
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development of a ru c catalyst for glycerol hydrogenolysis in combinatIon with an Ion Exchange Resin
Applied Catalysis A-general, 2007Co-Authors: Tomohisa Miyazawa, Kimio Kunimori, Shuichi Koso, Keiichi TomishigeAbstract:Abstract The combinatIon of Ru/C and Amberlyst Ion-Exchange Resin is effective for the dehydratIon and hydrogenatIon (denoted as hydrogenolysis) of glycerol to 1,2-propanediol under mild reactIon conditIons (393 K). A Ru/C catalyst prepared by using active carbon with a low surface area (∼250 m2/g) showed better performance than that prepared by using active carbon with a high surface area. In additIon, treatment of Ru/C catalysts prepared from Ru(NO)(NO3)3 with Ar flowing at the appropriate temperature enhanced the performance compared to that of the commercially available Ru/C catalysts. This temperature treatment can be influenced by the decompositIon of Ru precursor salt and aggregatIon of Ru metal particles. In additIon, the degradatIon reactIon as a side-reactIon to C1 and C2 compounds of glycerol hydrogenolysis was more structure-sensitive than the hydrogenolysis reactIon, and the selectivity of hydrogenolysis was lower on smaller Ru particles. The combinatIon of Ru/C with the Amberlyst Resin enhanced the turnover frequency of 1,2-propanediol formatIon drastically, and this indicates that 1,2-propanediol can be formed mainly by dehydratIon of glycerol to acetol catalyzed by Amberlyst and subsequent hydrogenatIon of acetol to 1,2-propanediol catalyzed by Ru/C.
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glycerol conversIon in the aqueous solutIon under hydrogen over ru c an Ion Exchange Resin and its reactIon mechanism
Journal of Catalysis, 2006Co-Authors: Tomohisa Miyazawa, Yohei Kusunoki, Kimio Kunimori, Keiichi TomishigeAbstract:Abstract Of the various noble metals (Ru/C, Rh/C, Pt/C, and Pd/C) and acid catalysts [an Ion-Exchange Resin (Amberlyst), H2SO4(aq), and HCl(aq)], the combinatIon of Ru/C with Amberlyst is effective in the dehydratIon + hydrogenatIon (i.e., hydrogenolysis) of glycerol under mild reactIon conditIons (393 K, 8.0 MPa). The dehydratIon of glycerol to acetol is catalyzed by the acid catalysts. The subsequent hydrogenatIon of acetol on the metal catalysts gives 1,2-propanediol. The activity of the metal catalyst + Amberlyst in glycerol hydrogenolysis can be related to that of acetol hydrogenatIon over the metal catalysts. Regarding acid catalysts, H2SO4(aq) shows lower glycerol dehydratIon activity than Amberlyst, and HCl(aq) strongly decreases the activity of acetol hydrogenatIon on Ru/C. In additIon, the OH group on Ru/C can also catalyze the dehydratIon of glycerol to 3-hydroxypropIonaldehyde, which can then be converted to 1,3-propanediol through subsequent hydrogenatIon and other degradatIon products.
Kimio Kunimori - One of the best experts on this subject based on the ideXlab platform.
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development of a ru c catalyst for glycerol hydrogenolysis in combinatIon with an Ion Exchange Resin
Applied Catalysis A-general, 2007Co-Authors: Tomohisa Miyazawa, Kimio Kunimori, Shuichi Koso, Keiichi TomishigeAbstract:Abstract The combinatIon of Ru/C and Amberlyst Ion-Exchange Resin is effective for the dehydratIon and hydrogenatIon (denoted as hydrogenolysis) of glycerol to 1,2-propanediol under mild reactIon conditIons (393 K). A Ru/C catalyst prepared by using active carbon with a low surface area (∼250 m2/g) showed better performance than that prepared by using active carbon with a high surface area. In additIon, treatment of Ru/C catalysts prepared from Ru(NO)(NO3)3 with Ar flowing at the appropriate temperature enhanced the performance compared to that of the commercially available Ru/C catalysts. This temperature treatment can be influenced by the decompositIon of Ru precursor salt and aggregatIon of Ru metal particles. In additIon, the degradatIon reactIon as a side-reactIon to C1 and C2 compounds of glycerol hydrogenolysis was more structure-sensitive than the hydrogenolysis reactIon, and the selectivity of hydrogenolysis was lower on smaller Ru particles. The combinatIon of Ru/C with the Amberlyst Resin enhanced the turnover frequency of 1,2-propanediol formatIon drastically, and this indicates that 1,2-propanediol can be formed mainly by dehydratIon of glycerol to acetol catalyzed by Amberlyst and subsequent hydrogenatIon of acetol to 1,2-propanediol catalyzed by Ru/C.
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glycerol conversIon in the aqueous solutIon under hydrogen over ru c an Ion Exchange Resin and its reactIon mechanism
Journal of Catalysis, 2006Co-Authors: Tomohisa Miyazawa, Yohei Kusunoki, Kimio Kunimori, Keiichi TomishigeAbstract:Abstract Of the various noble metals (Ru/C, Rh/C, Pt/C, and Pd/C) and acid catalysts [an Ion-Exchange Resin (Amberlyst), H2SO4(aq), and HCl(aq)], the combinatIon of Ru/C with Amberlyst is effective in the dehydratIon + hydrogenatIon (i.e., hydrogenolysis) of glycerol under mild reactIon conditIons (393 K, 8.0 MPa). The dehydratIon of glycerol to acetol is catalyzed by the acid catalysts. The subsequent hydrogenatIon of acetol on the metal catalysts gives 1,2-propanediol. The activity of the metal catalyst + Amberlyst in glycerol hydrogenolysis can be related to that of acetol hydrogenatIon over the metal catalysts. Regarding acid catalysts, H2SO4(aq) shows lower glycerol dehydratIon activity than Amberlyst, and HCl(aq) strongly decreases the activity of acetol hydrogenatIon on Ru/C. In additIon, the OH group on Ru/C can also catalyze the dehydratIon of glycerol to 3-hydroxypropIonaldehyde, which can then be converted to 1,3-propanediol through subsequent hydrogenatIon and other degradatIon products.
