臭氧氧化对糖精氯消毒衍生DBPs的影响

Effect of ozonation on DBPs produced by saccharin during chlorination

针对糖精(SAC)在饮用水处理系统中的转化可能影响水质安全的问题,对其衍生消毒副产物(DBPs)的生成风险进行研究,考察臭氧深度处理工艺对SAC衍生DBPs种类及水平的影响.研究结果表明:氯直接氧化SAC可产生三氯甲烷(TCM)、二氯乙酸(DCAA)、三氯乙酸(TCAA)和二氯乙腈(DCAN)等DBPs,其生成势分别为8.1,0.4,1.2,0.1μg/mg;经臭氧氧化后,SAC衍生氯系DBPs主要包括TCM,DCAA,TCAA和DCAN,种类未发生变化,生成势分别为24.6,15.7,49.2,17.8μg/mg,分别为直接氯化DBPs的3,39,41,178倍;SAC经臭氧氧化后,发生羟基取代及断键、开环等反应,从而产生酚、马来酸和氨基苯酚等物质,后续氯氧化产生了更高生成势的TCM,DCAA,TCAA和DCAN等DBPs;SAC氯化衍生TCM,DCAA,TCAA和DCAN的生成势随臭氧氧化时间的延长先升高后降低,在20 min时达到最大.

Aiming at the problem that transformation of saccharin(SAC)in drinking water treatment system may affect the safety of water quality,the risk of its derived disinfection by-products(DBPs)was studied,and the effect of ozonation advance treatment on DBPs derived by SAC was investigated.Research results show that the SAC could produce DBPs including trichloromethane(TCM),dichloroacetic acid(DCAA),trichloroacetic acid(TCAA)and dichloroacetonitrile(DCAN)during chlorination process,and the formation potentials of the above-mentioned DBPs are 8.1,0.4,1.2,0.1μg/mg,respectively.After ozonation,the DBPs derived from SAC chlorination are the same categories,which are TCM,DCAA,TCAA and DCAN,however,the DBPs formation potentials increase to 24.6,15.7,49.2,17.8μg/mg respectively,which are 3,39,41 and 178 times of those by direct chlorination,respectively.After the ozonation of SAC,hydroxyl substitution,bond breaking and ring opening reactions would occur to produce phenol,maleic acid and aminophenol,which could facilely generate more TCM,DCAA,TCAA and DCAN.The formation potentials of TCM,DCAA,TCAA and DCAN produced by SAC during chlorination would increase first and then decrease along with the extension of ozonation contact time,and reach the maximum yields at 20 min.