Construction Of A Three-Dimensional Electric Fenton Device And Its Degredation Of Rhodamine B

There are many kinds of dyes,which bring great growth to the economy,and also cause serious environmental pollution.Because of the high chemical stability and low biodegradability of dye wastewater,it has been a difficult problem in wastewater treatment.However,the electric Fenton technology has been widely concerned in the field of treatment of refractory organic wastewater because of its advantages of friendly environment and high efficiency and controllable.Therefore,this paper constructs a three-dimensional electric Fenton system by preparing gas diffusion electrodes and heterogeneous catalysts,and conducts research on rhodamine B dye as the target pollutant.The main research results are as follows:The preparation and characterization of reduced graphene oxide（r-GO）and NSB-reduced graphene oxide（NSB-r-GO）using urea-thiourea-boric acid as raw materials were studied.The results of physical characterization show that compared with r-GO materials,the surface of NSB-r-GO materials successfully introduced heteroatom NSB,which increases the specific surface area and defect density of carbon based materials,exposes more reactive sites,which is conducive to the occurrence of oxygen reduction reaction.The electrochemical CV curves show that the oxygen reduction peaks of r-GO and NSB-r-GO gas diffusion electrodes are obvious,and the peak value correction of oxygen reduction of NSB-r-GO gas diffusion electrode shows that the oxygen reduction activity of NSB-r-GO is higher.Therefore,NSB-r-GO material is used as the catalytic layer of gas diffusion electrode.The process parameters of the photocatalytic production of H₂O₂by NSB-r-GO gas diffusion electrode were optimized.The results showed that under the conditions of 80m L 0.1 mol·L^-1Na₂SO₄electrolyte,constant current density 10 m A·cm^-2,aeration flow1.0 L·min^-1,diffusion layer PTFE emulsion dosage 0.15 m L,catalytic layer PTFE emulsion dosage 0.04 m L,the cumulative concentration of H₂O₂reached 105.43 mg·L^-1and the current efficiency was 52.71%after the electrolysis for 30 min.The output of H₂O₂can reach 96.81 mg·L^-1after 7 times of repeated use,which indicates that the electrode has certain cycle stability.In order to construct a three-dimensional electric Fenton reactor,Heterogeneous catalysts CuFe O@C were synthesized and characterized.The results show that the calcined heterogeneous catalyst CuFe O@C is mainly composed of CuO and CuFe₂O₄.The decolorization of Rhodamine B was carried out by three-dimensional Fenton system,and the effects of different operating conditions on the degradation rate of Rhodamine B were studied.The results showed that when electrolyte concentration was 0.075 mol·L^-1,Rhodamine B initial concentration was 30 mg·L^-1and dosage of heterogeneous catalyst CuFe O@C was 1.25 g·L^-1,Rhodamine B could be decolorized completely within 15minutes.The addition of NO₃^-and Cl^-is beneficial to the degradation of rhodamine B.The performance and mechanism of three-dimensional Fenton system are analyzed.The results of performance analysis show that the three-dimensional Fenton method has a universal applicability in the treatment of pollutants,and heterogeneous catalysts CuFe O@C also has good cyclic stability.The mechanism experiment shows that·OH radicals play a major role in the degradation of three-dimensional electric Fenton.The results of the kinetic analysis show that the degradation of Rhodamine B by three-dimensional electro Fenton method is in accordance with the first order reaction kinetics.