Kinetics of reactions between chlorine and the cyanobacterial toxins microcystins
Kinetics of reactions between chlorine and the cyanobacterial toxins microcystins
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DOI：
10.1016/j.watres.2005.01.022
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发表时间：
2005-04-01
期刊：
影响因子：
12.8
通讯作者：
Meriluoto, J
中科院分区：
文献类型：
--
作者：
Acero, JL;Rodriguez, E;Meriluoto, J
蓝细菌大量繁殖会产生毒素，污染饮用水源。在自来水厂常用的氧化剂和消毒剂中，氯被发现对微囊藻毒素的降解是有效的。在本研究中，未知的二级速率常数的微囊藻毒素-LR（MC-LR），-RR和-YR与氯的反应在很宽的pH值范围内进行了测定。结果发现，pH值的增加对微囊藻毒素的降解率有负面影响。20 ℃时MC-LR氯化反应的表观二级速率常数从pH 4.8时的475 M-1 s（-1）变化到pH 8.8时的9.8 M-1 s（-1）。从这些表观二级速率常数，MC-LR与次氯酸（HOCl）和次氯酸盐（ClO-）的反应速率常数进行了评估。半衰期范围从分钟（pH 6）到1小时（pH 8）的恒定残留氯浓度为1.0 - 0.5毫克I-1，典型的氧化预处理和最终消毒。发现MC-RR和MC-YR与氯的反应性相似。因此，氯化是一个可行的选择，微囊藻毒素降解过程中的氧化和消毒过程中，并可以在饮用水处理蓝藻毒素的风险，如果保持pH值低于8。爱思唯尔有限公司出版
Blooms of cyanobacteria can give rise to the production of toxins which contaminate drinking water sources. Among the oxidants and disinfectants typically applied in waterworks, chlorine has been found to be effective for the degradation of microcystins. In the present study, unknown second-order rate constants for the reactions of microcystin-LR (MC-LR), -RR and -YR with chlorine were determined over a wide pH range. It was found that an increase of pH has a negative effect on the microcystin degradation rate. Apparent second-order rate constant for the chlorination of MC-LR at 20 degrees C varied from 475 M-1 s(-1) at pH 4.8 to 9.8 M-1 s(-1) at pH 8.8. From these apparent second-order rate constants, rate constants for the reactions of MC-LR with hypochlorous acid (HOCl) and hypochlorite (ClO-) were evaluated. Half-life times ranged from minutes at pH 6 to I h at pH 8 for a constant residual chlorine concentration of 1.0-0.5 mg I-1, typical of oxidation pre-treatment and final disinfection. Similar reactivity with chlorine was found for MC-RR and MC-YR. Therefore, chlorination is a feasible option for microcystin degradation during oxidation and disinfection processes, and can be applied in drinking water treatment in case of cyanobacterial toxin risk if the pH is kept below 8. Published by Elsevier Ltd.