环糊精键合Fe-TAML催化剂的制备及其活化H_(2)O_(2)氧化水中有机微污染物  

Preparation of Catalyst Cyclodextrin-Fe-TAML to Activate H_(2)O_(2) and Oxidize Organic Micropollutants in Water

作　　者：刘清泉 蔡本哲 蔡喜运[1] LIU Qing-quan;CAI Ben-zhe;CAI Xi-yun(Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of Education),School of Environmental Science and Technology,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学环境学院,工业生态与环境工程教育部重点实验室,大连116024

出　　处：《环境科学》2023年第7期3978-3989,共12页Environmental Science

基　　金：国家重点研发计划项目(2019YFC1803803);国家自然科学基金项目(21677024)。

摘　　要：为了提高Fe-TAML催化剂的稳定性和催化活性,通过磺酰氯化反应、金属螯合反应和亲核取代反应等方法将Fe-TAML与环糊精(CD)以共价键形式结合,制备了单-6-氧-CD键合Fe-TAML催化剂(CD-Fe-TAML).开展了CD-Fe-TAML的催化活性、稳定性测试及其活化H_(2)O_(2)氧化降解水中抗生素和农药等34种有机微污染物研究.与Fe-TAML相比,CD-Fe-TAML在pH为7.0条件下活化H_(2)O_(2)生成高价铁的速率提高49倍,对底物的催化降解速率提高25倍,且其自氧化速率降低70%.CD-Fe-TAML在pH为3.0~10.0范围内的稳定性比Fe-TAML的稳定性提高0.7~699倍,其中,在pH为3.0~7.0范围内提高33~699倍.CD-Fe-TAML的分子结构中的磺酸基官能团具有吸电子效应,能增加活性中心中Fe离子的正电荷密度,不仅加快H_(2)O_(2)的过氧键裂解和高价铁物种的生成,提高Fe-TAML的催化活性,还能提高其水解稳定性.同时,分子结构中的CD基团具有“电子穿梭体”效应和包合作用,前者通过加快活性中心Fe-TAML与H_(2)O_(2)之间的电子转移而促进高价铁物种的生成,提高Fe-TAML的催化活性;后者能通过对活性中心Fe-TAML的包合而抑制了其水解和自氧化反应,提高其稳定性.与Fe-TAML/H_(2)O_(2)相比,在pH为5.0~7.0的范围内,CD-Fe-TAML/H_(2)O_(2)对有机微污染物的降解速率提高了0.4~59倍.在pH为8.0条件下,CD-Fe-TAML/H_(2)O_(2)对摩尔体积小于0.20 L·mol^(-1)的啶虫脒和磺胺嘧啶等9种微污染物的降解速率提高0.3~1.1倍,对摩尔体积大于0.20 L·mol^(-1)的微污染物的降解速率没有显著性变化.碘离子的氧化实验结果显示,水中的I^(-)没有被CD-Fe-TAML/H_(2)O_(2)体系氧化为HIO或IO^(-),不会进一步与DOM反应生成碘代消毒副产品(I-DBPs).同时,CD-Fe-TAML/H_(2)O_(2)对地表水水样中微污染物的降解不受DOM和无机盐离子等水体组分的干扰.所构建的CD-Fe-TAML/H_(2)O_(2)体系具有比Fe-TAML/H_(2)O_(2)体系更高的催化降解活性和稳定性,在水�In order to improve the stability and catalytic activity of Fe-TAML,mono-6-oxy-cyclodextrin bonded Fe-TAML catalyst(CD-Fe-TAML)was prepared by bonding Fe-TAML with cyclodextrin(CD)through chlorosulfonylation reaction,metal chelation reaction,and nucleophilic substitution reaction.The catalytic activity and stability of CD-Fe-TAML and the oxidation degradation efficiencies of 34 organic micropollutants such as antibiotics and pesticides by activation of H_(2)O_(2)in water were studied.Compared with that of Fe-TAML,CD-Fe-TAML at pH 7.0 had a 49-fold and 25-fold increase in the rate of activating H_(2)O_(2) to produce iron(Ⅴ/Ⅳ)-oxo intermediates and the degradation rate of the substrate,respectively,and its self-oxidation rate was reduced by 70%.The stability of CD-Fe-TAML was 0.7-699 times higher than that of Fe-TAML in the pH range of 3.0-10.0.Specifically,the stability of CD-Fe-TAML was 33-699 times higher than that of Fe-TAML in the pH range of 3.0-7.0.The sulfonic acid group in the molecular structure of CD-Fe-TAML had an electrophilic effect,which could increase the positive charge density of Fe in the active center,accelerate the O-O bond cleavage of H_(2)O_(2) and the generation of iron(Ⅴ/Ⅳ)-oxo intermediates,improve the catalytic activity of Fe-TAML,and also improve its hydrolysis stability.Meanwhile,the CD group in the molecular structure had the"electron shuttle"effect and inclusion effect.The former could accelerate the electron transfer between the active center Fe-TAML and H_(2)O_(2) to improve the catalytic activity of Fe-TAML.The latter could inhibit the hydrolysis and self-oxidation of the active center Fe-TAML by inclusion or binding of the hydrolysis sites and oxidation sites,thus improving its stability.The degradation efficiencies of micropollutants by CD-Fe-TAML/H_(2)O_(2) under weakly acidic and neutral conditions(in the pH range of 5.0-7.0)were 0.4-59 times higher than those of Fe-TAML/H_(2)O_(2).The degradation efficiencies of CD-Fe-TAML/H_(2)O_(2) on nine micropollutants with a mola

关 键 词：环糊精键合Fe-TAML 催化剂 过氧化氢 有机微污染物 氧化降解 

分 类 号：X703.1[环境科学与工程—环境工程]