Investigating The Chlorination Of Typical PPCPs In Drinking Water Distribution System

As pharmaceutical and personal care products(PPCPs)consist of a wide range of hazardous chemicals as emerging pollutants,so they have received more and more attention.PPCPs can enter the aquatic environment through a variety of ways,however,chlorine disinfection has been widely used by most of the water treatment plants up to now.Therefore,it is necessary to investigate the chlorination of PPCPs,especially of the chlorination of PPCPs in drinking water distribution system.It is particularly important for PPCPs regulation in water distribution system to analyze the main factors of chlorine degradation reaction,and to investigate the influence of multi-factor.Typical PPCPs degradation reactions by chlorine were studied,the main conclusions were made as followed:(1)Basing on the detection and analysis of PPCPs in water distribution system,16 typical kinds of PPCPs were determined combined with relevant literature,the detection method which could detect 16 PPCPs simultaneously was established as well;(2)The test of 16 PPCPs degradation reaction by chlorine was conducted in order to explore the chlorination of typical PPCPs.Depending on the circumstances of reaction,PPCPs could be divided into three categories: difficult to be degraded by chlorine,able to be degraded and easy to be degraded by chlorine.Disopyramide and sulfamethoxazole were selected by analyzing the circumstances of degradation reaction to explore the reaction order,which are at a higher concentration lever in water distribution system.Chlorine degradation reactions of disopyramide and sulfamethoxazole were forth-order kinetics model when 20 mL of sodium hypochlorite was added;(3)The main factors of chlorine degradation reaction were determined,i.e.pH,temperature and the initial concentration.The influence of these three factors was explored respectively.Disopyramide was easier to be degradated by chlorine in alkaline water environment,and the reaction rate increased when the initial concentration decreased.However chlorine degradation reactions of sulfamethoxazole were reversed.The reaction rate of either of disopyramide and sulfamethoxazole was positively correlated with temperature.(4)The comprehensive influence on typical PPCPs(a case study of disopyramide)chlorine degradation reactions of the three factors was explored by Box-Behnken response surface methodology.By software processing,an accurate quadratic mathematical model of the reaction factors and the reaction rate was established.