卤代醛/酮消毒副产物的生成潜能及其前驱物的结构特征

Formation potential of halogenated aldehydes and ketones disinfection by-products and structural characteristics of their precursors

卤代醛和卤代酮类消毒副产物因具有"致畸、致癌、致突变"作用而倍受关注.对卤代醛/酮类消毒副产物控制及其前体物识别对饮用水安全保障具有重要意义.以大分子酸、疏水性酸、芳香族类亲水酸、亲水酸、糖类和氨基酸6类共14种常见有机物为对象,研究了不同有机物在氯化消毒过程中的卤代醛/酮生成潜力.结果表明,富里酸、柠檬酸、苹果酸、L-苏氨酸和L-天冬酰胺具有较高的卤代醛/酮生成势.有机物生成卤代醛/酮的过程包括2个阶段:前体物首先经氧化、脱羧等过程生成乙醛和丙酮,乙醛和丙酮被逐步氯代而生成氯代醛和氯代酮.实际水体的消毒实验表明,卤代醛/酮的生成势与水样中有机物的浓度无必然联系,但与水样中醇羟基及羰基官能团的含量呈正相关(R^2=0.69—0.98).

Disinfection by products of halogenated aldehydes and ketones have attracted great attention due to their teratogenic,carcinogenic and mutagenic effects.The prevention of halogenated aldehydes/ketones and the identification of their precursors are of great significance for the safety of drinking water.The formation potential of halogenated aldehydes/ketones in chlorination disinfection process was investigated with 14 natural organic substances in 6 categories,including macromoleculer acids,hydrophobic acids,aromatic hydrophilic acids,hydrophilic acids,saccharides and amino acids.The results showed that high halogenated aldehyde/ketone formation potential was observed when fulvic acid,citric acid,malic acid,L threonine and L asparagine were used as precursors.And the formation pathway of halogenated aldehydes/ketones from organic compounds included two stages:the precursors were first transformed into acetaldehyde and acetone through oxidation and decarboxylation,and then acetaldehyde and acetone were gradually chlorinated to produce chloroacetaldehydes and chloroacetones.The disinfection experiments in real water samples showed that the formation potential of halogenated aldehydes/ketones was not necessarily related to the concentration of organic compounds in the water samples,but positively related to the content of alcohol hydroxyl and carbonyl functional groups(R^2=0.69—0.98).