Research On Activated Carbon Fiber (ACF) Cathode Enhanced Degradation Of Diclofenac From Aqueous Solution In Coupling Electrolysis With Permanganate

In recent years,water shortage and water pollution are serious problems that need urgent solution.With diclofenac?DCF?complex detection as the representative of the organic drug in the water if.However DCF itself is toxic,which can cause lesions of human organs,blood diseases,fish tissue damage.In the process of water treatment,the commonly used treatment of DCF has the disadvantages of low mineralization rate and poor detoxification.PM is often used as water treatment agent due to its strong oxidizing,easy storage,and environmental friendliness.The enhanced permanganate technology can increase its oxidizing,but it has limitations.The first proposed degradation DCF with E-ACF-PM,and analysis from the degradation efficiency,influencing factors,reaction mechanism.It is innovative to propose a method for strengthening permanganate production of Mn?III?and oxidizing organic compounds by using an active carbon fiber cathode,and analyzing the valence state change and oxidation rule of Mn during the process.The first,compared the degradation rate of DCF with PM,E-PM and E-ACF-PM system,and studied the degradation effect of E-ACF-PM system.Analysis of the degradation rate and mineralization rate of DCF by PM,ACF,E?ACF?,ACF-PM and E-ACF-PM systems showed that the both of DCF in E-ACF-PM system Optimally,complete degradation of DCF is achieved and the mineralization rate is as high as 82%.The pseudo-first-order kinetic model was established to fit the different process.The residual rate of permanganate of DCF degradation by PM,ACF-PM and E-ACF-PM system was studied.The residual amount of permanganate is lowest of E-ACF-PM,which was only 10%.E-ACF-PM system,has higher permanganate utilization than other process and are more conducive to the degradation of DCF.The effects of experimental factors such as permanganate concentration,current intensity,initial pH,electrolyte type and concentration,humic acid and source water on the degradation of DCF by E-ACF-PM system were investigated.The results showed that with the increase of permanganate concentration and current intensity,the degradation rate increased.The effect of pH was greater,and the degradation efficiency is better in acidic conditions.Organic matter can affect the degradation efficiency,as humic acid can promote the oxidation effect of the system.Tap water,surface water,and ultrapure water can effect on the degradation of DCF.The effect of surface water was best,and tap water was the worst.Secondly,the cathode of activated carbon fiber in E-ACF-PM system was studied.Repeated use of activated carbon fiber cathode for many times,the system has little change in the degradation rate of DCF.SEM,EDS,BET,FTIR,XPS and Boehm techniques were used to characterize the activated carbon fibers before and after ACF-PM and E-ACF-PM reaction.Through repeated experiments and characterization,it was shown that PM was activated to the intermediate valence state Mn during the degradation of DCF,which rapidly oxidized organic matter to form soluble Mn(such as Mn²⁺)into the water,making the cathode of activated carbon fiber available for multiple uses.The active carbon fiber cathode has adsorption and catalytic effect in this system.The possible role of free radicals in E-ACF-PM system was studied using MA and TBA as free radical scavengers.The results showed that the free radical effect in this system was negligible.The addition of NTA,EDTA,and PP complexing agents during the oxidation of DCF to the E-ACF-PM system inhibited the reaction.It is because the complexing agent can complex Mn?III?and generate weakly oxidized Mn?III?-PP.According to the full scan analysis,it is further confirmed that the active oxidant in the reaction is mainly Mn?III?,and the binding experiment and characterization are also performed.The valence changes and oxidation rules of Mn were analyzed.