Enhanced in-situ electro-generation of HO using PTFE and NHHCO modified C/PTFE electrode for treatment of landfill leachate.

In this study, the carbon black/polytetrafluoroethylene (C/PTFE) electrode was prepared under the best conditions, and then it was modified by PTFE and NHHCO to make a PTFE-C/PTFE electrode. PTFE-C/PTFE electrode was used to enhance HO in-situ electro-generation and the electro-peroxone process (EPP) treatment of leachate. Various analytical methods results were applied to prove that the PTFE-C/PTFE electrode greatly improved the performance of HO generation and electrode stability. The effects of initial pH, current intensity, ozone flow and Cl concentration on the removal of NH and chemical oxygen demand (COD) from landfill leachate were studied in the EPP with PTFE-C/PTFE as cathode (MEPP) by one factor at a time (OFAT) method. The initial pH value 7.5, current intensity 300 mA, ozone flow 875 mg/h and Cl concentration value 4198 mg/L were selected as the best operating parameters. A response surface methodology based on box-behnken design (BBD) was employed to optimize running conditions of the MEPP of leachate. After optimization, Mineralization efficiency of the NH and COD was obtained to be 79.83% and 52.14%, and biochemical oxygen demand (BOD)/COD ratio increased to 0.38 after 4 h. The removal curves of NH and COD in the MEPP conforms to the zero-order and first-order reaction kinetics, respectively. Three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) analysis shows that MEPP has a good removal effect on organics in leachate. Energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis were carried out for the cathode sediment, which was mainly magnesium ion silicate precipitation and NaCl.