茶多酚作为饮用水辅助消毒剂的作用机制研究

Due to the multiple chlorinated disinfection by-products, people questioned the safety of drinking water treated by traditional disinfection methods. For the green, efficiency, durable germicidal efficacy, tea polyphenols will become new environment-friendly secondary disinfectant combined with O3/UV disinfection process. Based on the analysis of the chemical structure of tea polyphenols and different microbial community structure of the water, the characteristics of the structure of the microbial flora under different contact time and different water conditions in the process of disinfection will be analyzed, with different molecular forms of tea polyphenols, such as ester type, non-ester type, cis structure and trans structure, etc.. The mechanism of the effects of tea polyphenols on the cell membrane of cell membrane and the difference in complexation of metal ions with number and position of coordination phenolic hydroxyl groups will be revealed. The interaction sites and binding law between phenolic hydroxyl groups, benzene rings and proteins will be determined. Besides, the optimized operation parameter of the selected tea polyphenols that take control of harmful organisms will be put forward. Aimed at keeping the safety of drinking water, green disinfection technology and its disinfection principle will be set up based on the disinfection process of O3/UV accompanied by a secondary disinfectant tea polyphenols. As a result, the basic theoretical supports will be provided for the establishment of the green drinking water disinfection technology of O3/UV assisted with tea polyphenols, as well as the safty control in drinking water disinfection process.

层出不穷的氯化消毒副产物使人们对经传统消毒方法处理的饮用水的安全性提出质疑，茶多酚因其绿色、高效、持久的杀菌效能，与臭氧/紫外线联合使用，将成为新型环保辅助消毒剂。本项目以茶多酚分子立体化学结构与水中微生物区系结构变化分析为基础，对比分析酯型、非酯型、顺式结构、反式结构等分子形式茶多酚在杀菌过程中不同接触时间、不同水相构成条件下水中微生物区系结构变化特征，揭示不同结构茶多酚对菌体细胞膜的扰动作用机制，明确配位酚羟基数量与位置对金属离子的络合作用差异性，探索茶多酚结构中酚羟基和苯环与蛋白质的作用位点与结合规律，提出优化的茶多酚单体控制水中有害微生物生长的最佳运行工况，建立以饮用水安全控制为目标以臭氧/紫外线为主消毒方法茶多酚为辅助消毒剂的环保消毒工艺及其消毒原理，为建立茶多酚与臭氧/紫外线联用的绿色饮用水消毒技术，保障饮用水消毒安全提供基础理论支撑。

传统消毒技术存在不足之处，如氯消毒易产生卤乙酸等副产物，紫外线和臭氧因无持久杀菌能力而不能独立发挥消毒作用等。项目适应加强饮用水安全保障和水质提升改善重大需求，建立臭氧/紫外线与茶多酚联用的消毒体系，全面开展茶多酚作为辅助消毒剂的作用机制研究。研究内容包括：针对茶多酚及其单体儿茶素EGCG和EGC，借助DiSC35和NPN荧光探针，揭示酚羟基数量和自由基活性是细菌细胞膜受损的关键因素；针对铜质管道开展EGCG与Cu2+络合试验，确定1:2的络合比，指出EGCG结构中B环和D环羟基发生配位络合反应的具体点位，揭示络合物为含有两个五元环的特殊结构，并从活性氧ROS变化角度，阐释EGCG-Cu络合物对大肠杆菌的杀灭机制；通过官能团分析、基因比对与电泳分析，明确茶多酚进入细菌细胞会影响二氢叶酸合成酶及肽键合成，最终对DNA和RNA的破坏率均达到50%以上；利用BAR反应器，建立臭氧/紫外线-茶多酚两种联合消毒系统，与臭氧/紫外线-次氯酸钠系统开展对比试验，高通量测序与宏基因组分析表明，以茶多酚为辅助消毒剂的系统，球墨铸铁管网中铁离子络合物缓蚀膜会增强消毒作用，PPR、PVC、不锈钢管网的管壁微生物均以变形菌门为主要菌群，占比均在97%以上，其中α-变形菌纲占比超过85%，γ-变形菌纲受抑制明显，芽单胞菌属、假单胞菌属等耐氯菌均体现出对茶多酚的敏感性；结合工况试验与水质参数检测，通过正交分析与响应曲面优化分析，确定以茶多酚为辅助消毒剂的较优运行工况为臭氧投加量2.5mg/L、臭氧接触时间25min、茶多酚投加量20mg/L。研究还提出茶多酚可与超滤膜技术联合应用，采用茶多酚作为唯一消毒剂可在低于5 mg/L的投加量下保障出水的微生物安全，有效降低药剂成本，并可避免消毒副产物生成。茶多酚健康、安全、持久的抑菌性质，为高品质饮用水处理系统、贮存时间长的饮水系统提供了新一代健康消毒剂。