温度对生物活性炭降解卤乙酸的影响

Effect of temperature on haloacetic acid degradation by biologically active carbon

卤乙酸(HAAs)是饮用水中常见的氯和氯胺消毒副产物,具有较高的亲水性与致癌性,为了保证水质与人体健康,各国均对其制定了相关规定。考察了生物活性碳(BAC)对9种HAA的去除性能,并探讨HAA生物降解效果随温度的变化情况与生物反应的去除机理,反应动力学与热力学。结果显示,BAC可有效去除水体中的一卤代与二卤代乙酸,难以去除三卤代乙酸。BAC的生物降解性能明显可分为2个部分:低温(5~15℃)基本不发生生物降解;高温(25~35℃)生物降解性能显著。在不同温度下,HAA的生物降解均符合一级反应动力学,反应速率常数为0.01~0.40 min-1;BAC降解HAA的过程不是逐级氢取代卤而是同时脱去所有卤素的反应,卤代乙酸生物反应的活化能为63.5~89.2 kJ/mol。

Haloacetic acids(HAAs),as ubiquitous disinfection byproducts in drinking water using chlorination and chloramination and with high hydrophilicity and carcinogenicity,have been regulated to ensure water quality and human health all over the world. The removal of nine HAAs by biologically active carbon(BAC) was investigated. The effect of temperature on HAA biodegradablities and HAA removal mechanism,reaction kinetics and thermodynamics were also discussed in this study. It demonstrated that BAC could availably remove monoand di-HAAs but was hard to degrade tri-HAAs. When the water temperature ranged from 5 to 15℃,the concentration of HAAs was almost constant,but in warmer water between 25 and 35℃,HAA was prone to degradation by BAC. Under various temperatures,the HAA biodegradation conformed to first order reaction kinetics with rate constants from 0. 01 to 0. 40 min-1. The HAA removal mechanism was not halogen sequentially replaced by hydrogen but all halogens of HAAs removed simultaneously. The activation energy of HAA biodegradations ranged from 63. 5 to 89. 2 kJ /mol.