Activated Carbon Fiber (ACF) Electrode Enhanced Degradation Of Carbamazepine From Aqueous Solution In Coupling Electrolysis With Persulfate System

Organic drugs contamination has become a global environmental problem after the ozone layer depletion and the greenhouse effect,which is gradually being concerned by the academic circles and society.As one kind of organic drugs,carbamazepine and its metabolites have persistence,and they are difficult to be removed thoroughly by the traditional water treatment process.Hence the advanced oxidation processes(AOPs)are employed in engineering projects.Recently,a new type of advanced oxidation processes based on the generation of sulfate radical has been developed rapidly and has been attracting increased attention in wastewater treatment field.In this background,activated carbon fiber(ACF)electrode enhanced degradation of carbamazepine from aqueous solutionin coupling electrolysis with persulfate system has been put forward,and the main researches are carried out as follows.First of all,the effects of different cathode materials,such as activated carbon fiber and titanium plating platinum(Ti/Pt)on the degradation of carbamazepine were applied in coupling electrolysis with persulfate system.When the activated carbon fiber cathode was used in this coupling system,the degradation effect of carbamazepine was much better than that of the platinum plated titanium.The effects of carbamazepine degradation by persulfate,adsorption,persulfate-activated carbon fiber(PS-ACF)coupling system,electrolysis and E-PS-ACF coupling system were studied.The results demonstrated that oxidation removal rate,mineralization rate and pseudo-first-order rate constants in E-PS-ACF coupling system were much higher than those of the other four wastewater treatment technologies.Sencondly,the effects of persulfate initial concentration,voltage,temperature and initial pH value on the degradation of carbamazepine in E-PS coupling system were researched.When the activated carbon fiber electrode was used,the degradation of carbamazepine firstly increased and then decreased with the increase of persulfate concentration.While the carbamazepine degradation rate increased with increasing the persulfate concentrationas the titanium plating platinum electrode used in E-PS coupling system.It was significant that voltage had an influence on carbamazepine degradation,and the removal rate increased with the increase of voltage.The degradation efficiency was enhanced as the solution temperature increased.According to the Arrhenius Equation,the activation energy of carbamazepine in E-PS coupling system were 39.69 kJ·mol-1 and 42.48 kJ·mol-1,respectively,when activated carbon fiber and titanium plating platinum electrode were used.The oxidation activation energy of carbamazepine using these two electrodes were relatively lower,which indicated that the reaction was easy to carry out and the temperature effect was not significant.The oxidation removal rate of carbamazepine decreased with the increase of initial pH value,and it was highest at pH3.0.Simultaneously,free radical scavenger experiment confirmed that the sulfate radical played a dominant role and hydroxyl radical occupied secondary status in the degradation of carbamazepine.At last,in order to improve the reuse times of activated carbon fiber and avoid the surface structure and chemical properties of activated carbon fiber being destroyed,activated carbon fiber repeated experiments were carried out in E-PS-ACF coupling system and PS-ACF coupling system,respectively.The results verified that cathode electric-field had protective effect on activated carbon fiber which could avoid the surface oxidation or destruction by persulfate.Activated carbon fiber could convert from promoter to catalyst by free electron implantation in cathode in activated persulfate process,and which greatly prolonged its service life and significantly improved the utilization rate of persulfate.Therefore,it is a deserved research direction that removal experiment and mechanism research of low concentration organic drugs in E-PS-ACF coupling system,which can provide theoretical basis and technical support to water treatment technologies based on coupling electrolysis with persulfate system.