pH介导铜络合物活化过一硫酸盐选择性氧化水体四环素的分子内电子转移机制  

Intramolecular Electron Transfer Mechanism of pH-Mediated Cupric Complexes Activated Peroxymonosulfate Selective Oxidation of Aqueous Tetracycline

作　　者：曾湘楚 叶雨婷 武哲 韦瑞松 刘欢 ZENG Xiangchu;YE Yuting;WU Zhe;WEI Ruisong;LIU Huan(Guangxi Collaborative Innovation Center of Modern Sericulture and Silk;Guangxi Key Laboratory of Sericulture Ecology and Applied Intelligent Technology,School of Chemistry and Bioengineering,Hechi University,Hechi 546300,China;Xi’an Ecological Environment Bureau,Xi’an 710000,China)

机构地区：[1]河池学院化学与生物工程学院,广西现代蚕桑丝绸协同创新中心 [2]广西蚕桑生态学与智能化技术应用重点实验室,河池546300 [3]西安市生态环境局,西安710000

出　　处：《高等学校化学学报》2024年第12期10-21,共12页Chemical Journal of Chinese Universities

基　　金：中国博士后科学基金(批准号:2024M751271);广西现代蚕桑丝绸协同创新中心基金(批准号:2023GXCSSC03);2023年度广西高校中青年教师科研基础能力提升项目(批准号:2024KY0623);河池学院高层次人才科研启动项目(批准号:2023GCC015,2021GCC031);2023年河池市本级财政科技计划项目(批准号:河科AC231107)资助.

摘　　要：虽然水中游离的Cu(Ⅱ)无法有效活化过一硫酸盐(PMS),但与四环素(TC)络合形成的铜络合物则具有活化PMS自催化降解TC的作用.紫外-可见分光光谱和高效液相色谱分析结果验证了Cu(Ⅱ)-TC混合溶液中铜络合物的形成;密度泛函理论(DFT)计算结果揭示了铜络合物形成的反应路径、分子结构模型、自由能变、态密度(DOS)和络合作用力.研究发现,Cu(H_(2)O)_(4)^(2+)中Cu的d轨道接受TC中羟基、羰基及酰胺基中O的p轨道孤对电子形成络合物.构筑的5种可能的络合形式均呈现稳定的二配位六元环状结构.其中,形成络合物M1的自由能变最小、结构最稳定.铜络合物形成的作用力主要为范德华力、弱相互作用、共价键、空间位阻及配位键等.Cu(Ⅱ)/PMS体系对TC具有显著的自催化降解作用,在240min内可以完全降解(降解率>99%);并且在碱性(pH=10)条件下,Cu(Ⅱ)络合物活化PMS原位生成Cu(Ⅲ)络合物的分子内电子转移过程主导了TC的选择性氧化.通过DFT计算从动态、微观视角进一步阐明了pH介导铜络合物活化PMS选择性氧化水体TC的分子内电子转移机制.Although aqueous dissociative Cu(Ⅱ)could not effectively activate peroxymonosulfate(PMS),the cupric complexes formed by complexing with tetracycline(TC)could activate PMS and realize self-catalytic degradation of TC.The generation of cupric complexes was verified by UV-Vis and high performance liquid chromatography(HPLC),and the reaction pathways,molecular structure model,free energy variation,density of states(DOS),and complexation interaction of cupric complexes were revealed by density functional theory(DFT)calculation.It was found that the d orbital of Cu in Cu(H2O)42+was complexed by accepting the lone pair electrons of p orbital from hydroxyl,carbonyl,and amide group O in TC,and there were five possible complexation models constructed,all of them showed a stable bidenate ligands and hexatomic-ring coordination structure,in which the free energy of complex M1 became the smallest and its structure was the most stable.The interaction of cupric complexes formation mainly included van der Waals force,weak interaction,covalent bond,steric hindrance,coordination bond,etc.Cu(Ⅱ)/PMS system had significant self-catalytic degradation of TC,which could be completely degraded within 240 min(degradation efficiency was greater than 99%).Furthermore,under alkaline conditions(pH=10),the activation of peroxymonosulfate by cupric complexes coupling Cu(Ⅲ)complexes generation in situ promoted an intramolecular electron transfer(IET)process dominating the selective oxidation of TC.The pH-mediated IET mechanism of cupric complexes activated peroxymonosulfate selective oxidation of aqueous tetracycline was further elucidated through DFT calculations from dynamic and microscopic perspectives.The new findings in this paper further verified the self-catalytic selective oxidation performance and mechanism by aqueous cupric complexes activated PMS system,which provided a potential solution for the synergistic decontamination of actual wastewater contaminated heavy metals and antibiotics.

关 键 词：铜络合物 过一硫酸盐 四环素 选择性氧化 

分 类 号：O611.2[理学—无机化学] O614.12[理学—化学]