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Nanocrystalline low-silica X zeolite as an efficient ion-exchanger enabling fast radioactive strontium capture

Frontiers of Chemical Science and Engineering 2024年第9期18卷 15-23页

作者： Hyungmin Jeon Susung Lee Jeong-Chul Kim minkee choi Department of Chemical and Biomolecular Engineering(BK21 Four) Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Center for Nanomaterials and Chemical Reactions Institute for Basic Science(IBS)Daejeon 34141Republic of Korea

NaA zeolite(Si/Al=1.00)has been commercially applied for capturing radioactive 90Sr^(2+)because of its high surface charge density,effectively stabilizing the multivalent ***,owing to its narrow micropore opening(4.0Å),large micron-sized crystallites,and bulkiness of hydrated Sr^(2+),the Sr^(2+)exchange over NaA has been limited by very slow *** this study,we synthesized nanocrystalline low-silica X by minimizing a water content in a synthesis gel and utilizing a methyl cellulose hydrogel as a crystal growth *** resulting zeolite exhibited high crystallinity and Al-rich framework(Si/Al of approximately 1.00)with the sole presence of tetrahedral Al sites,which are capable of high Sr^(2+)uptake and ion ***,the zeolite with a FAU topology has a much larger micropore opening size(7.4Å)and a much smaller crystallite size(~340 nm)than NaA,which enable significantly enhanced ion-exchange *** to conventional NaA,the nanocrystalline low-silica X exhibited remarkably increased Sr^(2+)-exchange kinetics(>18-fold larger rate constant)in batch *** both the nanocrystalline low-silica X and NaA exhibited comparable Sr^(2+)capacities under equilibrated conditions,the former demonstrated a 5.5-fold larger breakthrough volume than NaA under dynamic conditions,attributed to its significantly faster Sr^(2+)-exchange kinetics.

关键词： Sr^(2+)removal low-silica X zeolite nanocrystal hydrogel methyl cellulose

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Hydrogen spillover in nonreducible oxides:Mechanism and catalytic utilization

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Nano Research 2022年第12期15卷 10357-10365页

作者： Songhyun Lee Hyungjun Kim Ryong Ryoo Jeong Young Park minkee choi Charles D.Davidson School of Chemical Engineering Purdue UniversityWest LafayetteIndiana47907USA Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and TechnologyDaejeon34141Republic of Korea Department of Chemistry Korea Advanced Institute of Science and TechnologyDaejeon34141Republic of Korea KENTECH Laboratory for Chemical Environmental and Climate TechnologyKorea Institute of Energy Technology(KENTECH)200 Hyeoksin-roNaju58330Republic of Korea Center for Nanomaterials and Chemical Reactions Institute for Basic Science(IBS)Daejeon34141Republic of Korea

Hydrogen(H)spillover in nonreducible oxides such as zeolites and Al2O3 has been a highly controversial phenomenon in heterogeneous *** industrial catalysts are predominantly prepared using these materials as supports,it is important to understand the mechanism and catalytic functions of H spillover on their *** the past decade,fundamental studies on zeolite-encapsulated metal catalysts have revealed that H spillover and reverse spillover can be utilized in the design of hydrogenation and dehydrogenation catalysts with improved *** experimental and theoretical studies have indicated that H spillover can occur in nonreducible oxides when they possess substantial acid sites that aid the surface migration of active *** the present review,we will discuss the possible mechanisms of H spillover in nonreducible oxides and the unique opportunities of using this phenomenon for the design of advanced hydroprocessing catalysts.

关键词： hydrogen spillover nonreducible oxides zeolites hydroprocessing catalysts

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甘油三酯催化转化为柴油、喷气燃料和润滑油基础油

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Chinese Journal of Catalysis 2024年第3期58卷 15-24页

作者： Yaejun Baik Kyeongjin Lee minkee choi 韩国科学技术高级研究院化学与生物分子工程系韩国大田34141

将生物质转化为可持续燃料和化学品对于解决环境问题、减少碳排放、增强能源安全以及促进经济和社会发展至关重要.在众多生物质原料中,来自不同来源的甘油三酯,如植物油、动物脂肪和微藻油,因其低氧含量和脂肪酸单元中的高度石蜡骨架,... 详细信息

将生物质转化为可持续燃料和化学品对于解决环境问题、减少碳排放、增强能源安全以及促进经济和社会发展至关重要.在众多生物质原料中,来自不同来源的甘油三酯,如植物油、动物脂肪和微藻油,因其低氧含量和脂肪酸单元中的高度石蜡骨架,与石油衍生烃的结构相似,而特别适合生产可持续的烃燃料和化学品.这意味着通过相对简单的催化转化过程,就能有效地将甘油三酯转化为烃类产物.本文概述了甘油三酯通过加氢过程转化为无氧燃料(如柴油和喷气燃料)以及润滑油基础油等高附加值产品的过程.此外,还根据反应机理讨论了所需催化剂的重要结构性质,以及甘油三酯的不同脂肪酸组成对催化转化过程的影响.

关键词：甘油三酯脱氧柴油喷气燃料润滑油基础油加氢处理的植物油加氢处理的酯和脂肪酸可持续航空燃料

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