Removal Of Refractory Organic Compounds By Electro-Fenton And Electro-Fenton-Like Methods

With the development of industry,refractory organic compounds in wastewater are increasing, and threatening the environment and human health. To remove these pollutants, the advanced oxidation processes (AOPs) emerge. Electro-Fenton (EF) and electro-Fenton-like (EFL) are powerful AOPs and have been focl in recent years.Since H₂O₂ generation is crucial in EF and EFL methods, influencing factors of electrochemically in-situ H₂O₂ generation were studied in this research, and optimization of operation conditions was made to improve the yield and generation rate of H₂O₂. Two dyes (Red MX-5B and 2BLN) were chosen as target organic compounds, and the removal efficiency was studied by EF and EFL methods. Key conclusions are as follows:(1) Based on orthogonal design experiments, optimal parameters were determined: initial pH value of cathode region = 2.00, current density (CD) = 10.2 A/m², oxygen flow (Q) = 0.4 L/min, concentration of supporting electrolyte (C) = 0.1 mol/L, distance between electrodes (d) = 6cm.(2) The concentration of H₂O₂ under certain conditions could be forecasted by regression analysis and BP artificial neural net works methods, and the average discrepancy of these two methods was 31.73% and 24.17%, respectively.(3) The efficiency and mechanism of reactive dye (Red MX-5B) and disperse dye (2BLN) removal by EF and EFL methods were studied. Results showed that these two methods removed the reactive dye by oxidation (after 4h electrolysis with ca. 90% decolourization ratio and about 50% mineralization ratio), and disperse dye by coagulation (ca. 90% decolourization ratio and mineralization ratio).(4) To reduce the operation cost, experiments using air instead of oxgen in EFL method were carried out. Results showed that the reactive dye could be decoloured effectively by air aeration if prolonging electrolyzation time or increasing the air flow.