The Role Of Acf As Cathode In Electro/Fe³⁺/Peroxydisulfate Oxidation Process ?EFP-ACF? For Removing Carbamazepine In Aqueous Solutions

With the rapid development of China's pharmaceutical industry,the problem of water pollution has become more and more serious,and the treatment of refractory organic wastewater has become a key and difficult point in water pollution control.Advanced oxidation processes?AOPs?based on persulfate have become potential applications because of their strong oxidizing ability,high treatment efficiency of target pollutants,mild reaction conditions,low price,and wide application range.In this paper,the persistent organic carbamazepine?CBZ?,which is difficult to remove by common biological methods,is chosen as the target pollutant.The feasibility of cathodic activated carbon fiber reinforced electric/trivalent iron/persulfate system for CBZ degradation is discussed.The effect of various experimental factors on the degradation effect was studied and analyzed,and the mechanism of action of the system was explored.Through comparing the experimental results,we can conclude that compared with ACF,Fe³⁺/PDS,E/PDS,E/Fe³⁺/PDS and E/ACF/PDS,the degradation rate,mineralization rate and quasi-first-order reaction rate constant of cathodic activated carbon fiber reinforced electrov/ferric/persulfate system?EFP-ACF?to carbamazepine were much higher than those of other treatments and produced a significant coupling effect.The influencing factors have shown that the cathodic activated carbon fiber reinforced electric/trivalent iron/persulfate system is greatly influenced by the initial pH of the solution,and the EFP-ACF system has higher removal of CBZ under acidic conditions.With the increase of trivalent iron,the degradation rate of CBZ increased.With the increase of persulfate dosage,the removal rate of CBZ increased first and then decreased.At 2 mM,the system had the highest degradation rate of CBZ.Increased current density helps the system to remove CBZ.The concentration of the solution electrolyte?sodium sulfate?also has a certain influence on CBZ,and the increase in concentration inhibits the removal of CBZ.As the temperature of the solution increased,the degradation rate of CBZ increased,and the activation energy of the reaction was22.87 KJ·mol^-1.The common inorganic anions such as chloride,nitrate and dihydrogen phosphate ions in the water source have a certain effect on the removal of CBZ in the EFP-ACF system:chloride ions have a catalytic effect on the removal of CBZ,and nitrate ions have an smaller influence on the removal of CBZ.,dihydrogen phosphate inhibits the removal of CBZ.In the process of mechanism exploration,the experimental analysis of recycle of activated carbon fibers showed that the degradation rate of carbamazepine gradually decreased in activated carbon fiber alone and in E/ACF/PDS system for 10 times,while in EFP-ACF The removal rate of carbamazepine in the system is basically the same,which shows that EFP-ACF system can effectively protect the activity of activated carbon fiber and prolong its service life.The activated carbon fibers after the reaction of the E/ACF/PDS system and the EFP-ACF system were analyzed by scanning electron microscopy-X-ray spectroscopy?SEM-EDS?.The results showed that the surface of activated carbon fibers in E/ACF/PDS system has axial cracks and adheres to a large number of crystals.However,the surface of the activated carbon fiber after the reaction of EFP-ACF system is smooth,and the apparent with the original activated carbon fiber is no different.By adding free radical inhibitors such as methanol,tert-butanol and phenol,the degradation of carbamazepine by EFP-ACF system not only has sulfate radical but also hydroxyl radical,in which sulfate radical plays a leading role,hydroxyl radical occupy a secondary position,and the reaction occurs mainly in the activated carbon fiber.