| Pharmaceuticals and Personal Care Products?PPCPs?are emerging micro-pollutants that are potentially harmful to the ecological environment and human health.They are pseudo-persistent,low in concentration,complex in composition,difficult to degrade,biologically toxic and a wide range of discharge characteristics.At present,the traditional domestic water treatment process has a poor removal effect for PPCPs,and there are fewer studies on the degradation of the PPCPs.There are mainly adsorption,ultraviolet photolysis,biological pool,Fenton and other methods,but these methods have complex operations,high energy consumption,high cost and low degradation of mineralization and other shortcomings.Therefore,the research and development of simple and cost-effective,efficient,and stable PPCPs removal technologies are important frontier issues in the field of water treatment at home and abroad.This study developed the new E-peroxone technology.Its main principle is:in a specially designed electrolytic cell,it is equipped with membrane electrode assemblies?MEA?that can produce ozone in situ and with carbon powder/polymer.Tetrafluoroethylene?C/PTFE?constitutes an electrode composite material for producing hydrogen peroxide,and the coupling effect between O3 and H2O2 is generated through in-situ electrolysis,and the oxidative degradation of·OH occurs to represent PPCPs represented by Carbamazepine?CBZ?and Ibuprofen?IBU?.In the experiment,MEA electrode system and C/PTFE electrode system were prepared by electrodeposition and hot pressing.The anodic Ti/SnO2-Sb of MEA system was analyzed using SEM,EDS,XRD,LSV and accelerated electrode life tests.Surface morphology,composition,crystal type,service life and oxygen evolution over potential?OEP?were used to prepare electrodes with the best ozone performance.The performances and conditions of electrolytic production of ozone,hydrogen peroxide,and hydroxyl radicals in the MEA system,C/PTFE system,and E-peroxone technology were optimized.Subsequently,two typical PPCPs,Carbamazepine and Ibuprofen,were investigated.The effects of the new E-peroxone technology on the parent and solution TOC degradation were investigated.The results showed that the new E-peroxone technology had better degradation effects on CBZ?10 mg/L?and IBU?20 mg/L?,and the complete degradation of its parent and TOC could be achieved within 10 min and 120 min.By examining the influencing factors such as the size of the current,the type of electrolyte,and the pH of the solution,the optimum reaction conditions were determined.The intermediate products of CBZ degradation were analyzed by HPLC-MS/MS.A total of 12 major products were detected by mass spectrometry,and the molecular chemical structure was preliminary identified.In the experiment,the structure was first inferred based on the mass spectral fragment ion map of each molecule corresponding to the peak time.With a series of OH-induced reactions,such as hydroxylation,carboxylation,decarboxylation,demethylation,hydrogen abstraction,and ring opening,these reactions ultimately result in the degradation of carbamazepine solution into carbon dioxide and water.Through the determination of the kinetic constants of degradation of IBU parent and TOC mineralization in each reaction,it was proved that the degradation met the pseudo-first-order kinetics reaction,and it was concluded that E-peroxone was at a current of300 mA,and the electrolyte was 0.05 M Na2SO4,and pH=7.The k values for IBU parent and TOC were 11.2x10-3S-1and 60.7x10-5S-1,respectively,which were much higer than those of other reactions.According to the mass spectrum of the intermediate product,the specific structural formula was analyzed,and its possible degradation pathway was inferred.The 15main intermediates were found to be gradually degraded into carbon dioxide and water,demonstrating that E-peroxone technology can completely eliminate the harm of PPCPs to the environment and provide experimental basis and data reference for the practical application of water treatment. |
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