Study On The Removal Mechanism Of Typical PPCPs In Water By Electro-activated Persulfate Coupled Carbon Membrane Syste

The mass production and use of pharmaceuticals and personal care products(PPCPs)have increased their presence in the environment.In recent years,with the rapid development of detection technology,a variety of PPCPs have appeared in public.The migration and transformation of PPCPs in the environment will eventually enter the human body through the food chain,causing a serious impact on human health.Based on the advanced persulfate oxidation technology,which has a good treatment effect for pollutants such as PPCPs,and based on the research idea of improving the mass transfer of electroactivated persulfate and efficient and rapid removal of pollutants,this study constructed the electroactivated persulfate coupled carbon membrane system for degradation of pollutants.The efficiency and mechanism of tubular carbon membrane and nitrogen-doped carbon membrane as anode electroactivated persulfate degradation of typical PPCPs were studied respectively,and the possible degradation path of typical PPCPs was proposed.In this study,the electroactivated persulfate coupled carbon membrane system was used to degrade triclosan(TCS),and the feasibility of the system was verified.The experimental results show that,under the three combined modes,only the system with electric field,persulfate and tubular carbon membrane simultaneously has the best degradation effect on TCS,and TCS can be completely removed within 90 min.The results of free radical quenching experiment and electron spin resonance showed that the main active species of the reaction system were hydroxyl radical,sulfate radical and singlet oxygen,among which hydroxyl radical and singlet oxygen played a major contribution,revealing that the reaction system had free radical oxidation and non-free radical oxidation process.In addition,two possible degradation pathways of TCS were proposed by degradation product analysis.To improve the membrane electrode electrochemical activity and electrical activation of persulfate efficiency of nitrogen doped carbon membrane electrode was prepared,using melamine as nitrogen source,graphite carbon materials as foundation,after two step sintering tubular nitrogen doped carbon membrane was prepared successfully,and studied in the different calcination temperature(500℃,600℃,700℃),in addition to the efficiency of pollutants.Through material characterization,it was found that N element was successfully doped into graphite.The tubular nitrogen-doped carbon membrane N-600 obtained by calcination at 600℃ contained three types,namely,pyridine nitrogen,pyrrole nitrogen and graphite nitrogen.The experimental results show that N-600 can degrade doxycycline hydrochloride(DC)more efficiently and quickly as an anode in the reaction system,and nitrogen doping does promote the degradation of pollutants in the reaction system.According to the results of free radical quenching experiment and electron spin resonance,the main active species are hydroxyl radical and singlet oxygen,and the reaction system involves both free radical oxidation and non-free radical oxidation.In addition,by analyzing the degradation products of DC,the possible degradation path of DC was proposed.In this study,the electroactivated persulfate coupled carbon membrane system showed excellent activation performance and could efficiently and rapidly degrade typical PPCPs,providing an efficient,rapid,green,low-cost and cost-effective method for the subsequent treatment of PPCPs,which is of great significance for environmental protection.