UV与氯联合消毒色氨酸生成碘乙酸的影响因素及路径  

Effect Factors and Generation Pathway of Iodoacetic Acid from Tryptophan During UV Irradiation Combined with Chlorine Disinfection

作　　者：杨玉龙[1] 费伟成 季京宣 张可佳[1] YANG Yulong;FEI Weicheng;JI Jingxuan;ZHANG Kejia(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,Zhejiang,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058

出　　处：《华南理工大学学报（自然科学版）》2022年第8期102-108,118,共8页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家科技重大专项(2017ZX07201004);国家自然科学基金资助项目(51978602)。

摘　　要：氨基酸是水体中普遍存在的一类含氮有机物,在I-存在下能产生毒性较强的碘代消毒副产物。为探明紫外光(UV)与氯联合消毒氨基酸生成碘乙酸的规律及机理,文中选用一种典型的氨基酸——色氨酸,建立了碘乙酸的生成动力学模型,探究了不同影响因素(包括UV照射时间、加氯量、pH值与Br-含量、I-含量)对碘乙酸生成的作用规律,并分析了碘乙酸的生成路径。结果表明:色氨酸在UV与氯联合消毒作用下生成碘乙酸的过程符合拟一级反应动力学,生成速率常数k为0.17h^(-1);UV照射时间、加氯量、pH值与Br-含量、I-含量对碘乙酸的生成均有较大影响。UV照射时间对碘乙酸的生成起促进作用,UV照射时间越长,碘乙酸生成量越大;pH值在6~8范围内时,碘乙酸的生成量随着pH值的升高而增加;随加氯量的增加碘乙酸生成量呈先增加后减少的趋势,当色氨酸浓度与加氯量的比例约为1∶2时,碘乙酸生成量最高,达15.30μg/L。文中建立了碘乙酸关于Br-含量和I-含量的生成模型,发现Br-含量对碘乙酸的生成起负相关作用,I-含量则起正相关作用,且后者对碘乙酸影响更大。文中还通过GCMS和LCMS-MS检测出了异戊酸酐、丁酸酐等4种中间产物,推测碘乙酸的生成路径为色氨酸在UV光解与羟基自由基作用下生成C_(12)H_(17)NO_(3),然后在HOCl和HOI氧化作用下依次生成异戊酸、丁酸,最终生成碘乙酸。Amino acid is a common nitrogenous compound in water.Iodine disinfection by-products could be pro⁃duced in the process of tryptophan chlorination disinfection in present of I-.To investigate the generation and mecha⁃nism of iodoacetic acid from amino acid during the use of UV and chlorine for disinfection,this paper selected a typi⁃cal iodoacetic acid,namely,tryptophan,and developed a generation kinetic model.In the investigation,first,the influ⁃ences of different factors including UV irradiation time,chlorine dosage,pH value,Br-content,and I-content on the generation of iodoacetic acid were explored,and the generation pathway of iodoacetic acid was further analyzed.The results show that the generation process of iodoacetic acid fits the pseudo first-order reaction kinetic model,with a generation rate constant k of 0.17h^(-1).UV irradiation time,chlorine dosage,pH value,Br-content,and I-content all exert big influence on the generation process of iodoacetic acid.UV irradiation time promotes the generation of iodoacetic acid,and the yield of iodoacetic acid increases with the increase of UV irradiation time.When the pH value is in the range of 6~8,the yield of iodoacetic acid increases with the pH value.The generation of iodoacetic acid exhibits a firstly increase and then decrease trend with the increase in chlorine.When the ration of the concentrations of trypto⁃phan and chlorine dosage is 1∶2,the production of IAA reaches the highest(15.30μg/L).The paper also established an equation describing the relationship among Br-content,I-content and iodoacetic acid yield.It is found that Br-has a negative correlation to the generation of iodoacetic acid,while I-content has a greater positive one.In addition,four products including butanoic acid anhydride and isovaleric anhydride were detected using LC-MS-MS and GC-MS.It is speculated that the generation path of iodoacetic acid is that C_(12)H_(17)NO_(3) is firstly produced from tryptophan through the action of UV photohydrolysis and hydroxyl radicals,and th

关 键 词：色氨酸 紫外光 消毒副产物 碘乙酸 生成路径 

分 类 号：TU991.2[建筑科学—市政工程]