2-甲基-4-氯苯氧乙酸及其脱氯产物的光化学降解

发布时间：2018-01-06 11:02

本文关键词：2-甲基-4-氯苯氧乙酸及其脱氯产物的光化学降解　出处：《环境工程学报》2017年02期 　论文类型：期刊论文

【摘要】：紫外消毒工艺作为废水/给水处理的重要步骤,不仅可以有效控制水中的病原体,而且可使废水或水源水中存在的一些污染物发生化学降解作用,但目前对这一作用过程的研究尚不完善。本文针对一种典型的除草剂——2-甲基-4-氯苯氧乙酸(MCPA)及其脱氯产物二甲基苯氧乙酸(MPA),研究了两者在紫外灯照射下的光化学行为,并进一步考察了波长、初始pH值、H2O2及水中其他共存物质对MCPA和MPA光降解效率的影响。研究结果表明,不同光源对MCPA的光降解速率大小为:254 nm波长紫外灯365 nm波长紫外灯可见光灯;低pH值不利于MCPA的光降解,但对MPA光降解的影响不大;在溶液中加入H2O2,会增大MCPA和MPA的光降解速率;MCPA的光降解过程符合一级动力学方程;腐殖酸(HA)会降低MCPA的光降解速率;MPA与MCPA呈现相似的光降解效应,但反应速率比MCPA略快,且在两者共存状态下会降低MCPA的光降解速率。
[Abstract]:UV disinfection process as an important step in water supply and wastewater treatment, not only can effectively control the water pollutants and pathogens, some of the wastewater or water in water chemical degradation, but the research process is not perfect. Aiming at a typical herbicide 2,4-dichlorophenoxyacetic acid 2- methyl -4- (MCPA) and dechlorination products of two methyl phenoxyacetic acid (MPA), the photochemical behavior of both under UV light irradiation, and further investigated the wavelength, initial pH value, H2O2 and other water coexisting substances on MCPA and MPA photodegradation efficiency. The results show that the degradation rate of different size the source of MCPA is: 254 nm wavelength ultraviolet lamp 365 nm wavelength UV light visible light; low pH value is not conducive to the photocatalytic degradation of MCPA, but the effect on the photodegradation of MPA is added in the solution; H2O2, MCPA and MP will increase The photodegradation rate of A; photocatalytic degradation process of MCPA with a kinetic equation; humic acid (HA) can reduce the degradation rate of MCPA; MPA and MCPA showed similar degradation effect, but the reaction rate is slightly faster than MCPA, and in both conditions will reduce the MCPA degradation rate.

【作者单位】：南京理工大学环境与生物工程学院;盐城师范学院;
【基金】：国家自然科学基金资助项目(51208257,51178223,51478223,21307103) 江苏省自然科学基金资助项目(BK2012405)
【分类号】：X703;TU991.2
【正文快照】： 2-甲基-4-氯苯氧乙酸(二甲四氯,MCPA,结构式见图1(a))为苯氧乙酸类选择性除草剂。MCPA的化学性质稳定,除草效果良好,较其他除草剂安全,故广泛应用于经济作物、草坪等生活用地除草[1]。然而该类农药在水中溶解度高[2],生产使用过程中易进入水环境,给人类的饮水安全带来严重威胁

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