摘要
氯代有机磷阻燃剂(chlorinated organophosphate flame retardants,Cl-OPFRs)已在环境中被广泛检出,由于其稳定、易迁移及具有生物毒性,因此已成为不可忽视的新兴有机污染物.本文选择环境中检出率较高的磷酸三(2-氯乙基)酯[tris(2-chloroethyl)phosphate,TCEP]为研究对象,以硫化零价铁(S/ZVI)和TCEP耐受降解菌(缓生新鞘氨醇菌,Novosphingobium tardaugens,N1)为研究材料,制备S/ZVI-微生物复合吸附剂(S/ZVI-N1),并对其去除TCEP的性能和降解途径进行探究.结果显示,S/ZVI-N1对TCEP的去除符合准一级动力学方程和Langmuir模型,表明该过程主要为单分子层的物理吸附作用,且根据准二级动力学方程的相关系数可知,在反应过程中同样存在化学吸附过程,S/ZVI-N1作用于TCEP 12h,去除率达58.9%,显著高于仅依靠Novosphingobium tardaugens的去除率(32.9%)和仅依靠S/ZVI的去除率(31.2%).产物分析表明,S/ZVI-N1 作用下TCEP较单独零价铁(zero-valent iron,ZVI)作用下降解更彻底,证明复合吸附剂中S/ZVI和Novosphingobium tardaugens之间存在协同作用,其最佳的反应条件为pH 5～7和30～35℃.微观分析显示,微生物和S/ZVI均参与了TCEP的降解.通过产物分析推导,S/ZVI-N1 对TCEP主要有 2 条降解途径,分别为S/ZVI主导的C—Cl键断裂和Novosphingobium tardaugens主导的O—P键断裂,最终生成磷酸三乙酯(triethyl phosphate,TEP)和磷酸(H3PO4).
Abstract
Chlorinated organophosphate flame retardants(Cl-OPFRs),a new type of pollutant,are widely detected in environment and has resistant to degradation,easy-migratory and biological toxicity.Tris(2-chloroethyl)phosphate(TCEP)with the highest detection rate in environment was chosen as the target pollutant in this study,and a composition adsorbent(named S/ZVI-N1)that prepared by zero-valent iron sulfide and Novosphingobium tardaugens was used as research material,to explore the removal performance and degrading pathway of TCEP by the S/ZVI-N1.The results showed that the removal of TCEP by S/ZVI-N1 fitted to the quasi-first-order kinetic equation and Langmuir model,which indicated this process was a physical adsorption of monolayer primarily and the R2 of quasi-second-order kinetic equation also proved the chemical adsorption.The removal rate of TCEP by S/ZVI-N1 was 58.9%after 12h,which was higher significantly than that by Novosphingobium tardaugens or S/ZVI only(biodegradation rate was 32.95%and S/ZVI removal rate was 31.2%).The analysis of degradation products indicated that the decomposition of TCEP by S/ZVI-N1 was more thorough than that by ZVI alone.This proved there was synergistic reaction between the S/ZVI and Novosphingobium tardaugens to remove TCEP,and the optimal conditions of TCEP removal was pH 5-7 and 30-35℃.The intermediates analysis could deduce two degradation pathways of TCEP by S/ZVI-N1,that one was the C—Cl bond broken down by S/ZVI and another was O—P bond broken down by Novosphingobium tardaugens,and the final products were triethyl phosphate(TEP)and H3PO4,which meant the completely degradation of TCEP.
基金项目
岭南现代农业科学与技术广东省实验室河源分中心自主科研项目(DT20220016)
河源市科技计划(河科2021001)
广东省自然科学基金青年提升项目(2023A1515030284)
岭南现代农业科学与技术广东省实验室河源分中心双聘团队项目(DT20220002)
国家科技期刊平台
NSTL
万方数据