邻苯二甲酸二甲酯的紫外光-H_2O_2降解机制研究  

Degradation Mechanisms of Dimethyl Phthalate in the UV-H_2O_2 System

作　　者：刘青[1] 陈成[1] 陈泓哲[1] 杨绍贵[1] 何欢[1] 孙成[1] 

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023

出　　处：《环境科学》2013年第7期2670-2676,共7页Environmental Science

基　　金：江苏省自然科学基金项目(BK2012732)

摘　　要：为研究邻苯二甲酸二甲酯(DMP)在紫外光(UV)-H2O2体系下的光降解机制,利用质谱仪鉴定了目标化合物的降解产物,并借此推测其可能的降解途径.结果表明,在UV-H2O2的体系中,10 mg.L-1的DMP在90 min内的降解率达到92.3%,溶液pH值由初始的6.50降至4.98.通过GC/MS、LC/MS分析,DMP在UV-H2O2降解过程中的产物有六类,并且推断出DMP的两条侧链同时发生水解作用,生成的邻苯二甲酸可以异构为更加稳定的对苯二甲酸.此外,DMP还可以发生苯环取代、侧链缩合成环等反应,最后,在.OH的作用下,DMP及其芳香族中间产物发生开环反应,苯环被破坏,生成多种小分子有机酸,并进一步矿化为CO2和水.To investigate the photodegradation process of dimethyl phthalate （DMP） in the ultraviolet light （UV）-H2O2 system, mass spectrometer was used to identify degradation products and further more, to speculate the possible mechanisms of degradation process. Experimental results showed that the degradation efficiency of 10 mg·L-1 DMP reached 92.3% in 90minutes in the UV-H2O2 system, and the more H2O2 was added, the faster DMP decomposed. The pH of DMP solution decreased from the initial 6.5 to 4.98, because of the generating of organic phenolic acids and small acid molecules generated by the degradation of DMP. By the GC/MS as well as LC/MS analysis, degradation products of the DMP in the UV-H2O2 system were thought to comprise six categories, from which we could infer that hydrolysis occurs simultaneously on the two side chains of the DMP, generating phthalic acid that can quickly change to the more stable terephthalic acid. In addition, DMP could also occur benzene ring replacement as well as the ring condensed of the side chains. Finally, by the role of·OH, DMP and its aromatic intermediates occurred ring-opening reaction, and benzene ring was destroyed and generated organic acids of small molecular, which was further mineralized to CO2 and water.

关 键 词：邻苯二甲酸二甲酯 紫外光-H2O2 降解机制 .OH 质谱分析 

分 类 号：X703.1[环境科学与工程—环境工程]