Treatment Bio-refractory Organic Wastewater By Electrocatalytic Oxidation Or The Synergy Technology Of Electrocatalytic Oxidation Coupling Nanofiltration

In recent years, there has been increasing interest in treating the bio-refractoryorganic wastewater efficiently. Electrocatalytic oxidation, as a kind of advancedoxidation process technologies, has strong oxidation performance and has beenreceived great attention because it is a clean process without adding any reagent andwithout the formation of heavy metal ions or sludge. But low current efficiency andlow capacity limits its industrial application. Nanofiltration is a effective and reliablemethod for the removal bio-refractory organic pollutants in the industrial wastewaterdue to the higher retention rate and no secondary pollution, while membrane foulingand concentration polarization effects the industrial application of the nanofiltrationprocess. The synergy technology of electrocatalytic oxidation coupling nanofiltrationhas been adopted to treat the bio-refractory wastewater in the current study. The newtechnology can treat wastewater efficiently by improving the efficiency, mitigatingthe concentration polarization and membrane fouling.In this paper, frabricating the electrodes with high catalytic activity is beendiscussed firstly. The influence of the catalytic layer microstructure and crystalstucture fabricated by three different thermal decomosition including alcohol solvents,ester solvents and Y-doped midified on the electrochemical properties anddegradation properties has been discussed. Our results confirmed that compared withalcohol solvents, catalytic layer frabricated by ester solvents is compact in size, higherproportion of Sb5+/Sb3+, low oxygen evolution activity and higher degradationperformance. In addition, in the condition of our experiments the catalytic layerfrabricated by electrodeposition is small particles size and higher degradationperformance compared with catalytic layer frabricated by thermal decomosition.Selecting three typical bio-refractory pollutants including the phenol, Acid Red73and antibiotics as the degradation objects we study the performance of catalyticdegradation of pollutants and its mechanism. Our results showed that the CODremoval up to97%within three hours with the current density of80mA cm-2.Addition of NaCl can significantly improve the current efficiency in the electrolysisAR73solution. Increasing the concentration of NaCl from0to9×10-3mol L-1CODremoval and current efficiency were increased by137%and36.9%. In addition, the COD removal of the industrial antibiotics wasteater attained70%and specific energyconsumption attained80KWh·(kg COD)-1with the current density of100mA cm-2Finally, we study the performance of the synergy technology of electrocatalyticoxidation coupling nanofiltration for treatment AR73wastewater. The model ofprediction the permeate flux and concentration polarization of the couple process hasbeen established by combining the catalytic degradation kinetics, one-dimensionalmodel of concentration polarization and non-equilibrium thermodynamics model.They have the similar trend between the model calculation results and theexperimental data with the several of operating conditions. The results also provedcatalytic degradation, as the dominant factor in the coupling process, can reduce theconcentration polarization and membrane surface concentration tremendously.All in all, our results showed that the synergy technology process is a highlyeffective way to removal the bio-refractory organic pollutions.