Utilizing Fe-C and PbO₂ modified electrodes for the electrochemical treatment of pickled vegetable wastewater

The objective of this study was to enhance the treatment efficiency of chemical oxygen demand (COD), total phosphorus (TP), and ammonia nitrogen (NH₄⁺-N) in pickled vegetable wastewater, as well as to improve the electrode's stability. Iron carbon micro-electrolysis (Fe–C) was employed for the pretreatment of wastewater, followed by a secondary treatment utilizing PbO₂ modified electrodes in the electrochemical advanced treatment process. The optimal operational conditions for Iron‑carbon micro-electrolysis (Fe/C = 1.2:1, volume ratio of iron to water = 1:1, pH = 5.4, reaction time = 4 min). For the electrochemical method, the optimal operational conditions included a plate spacing of 2.00 cm, a degradation temperature of 65 °C, a current density of 50 mA/cm², and a pH of 6. The optimal doping ratio of La in the Ti/SnO₂-Sb₂O₅/La-PbO₂ modified anode was found to be 10 mmol/L, with a theoretical lifespan of 5670 h. Under these conditions, the removal rates for TP, COD, NH₄⁺-N, and salinity (as Cl⁻) from the pickled vegetable wastewater were 96.67 %, 70.03 %, 79.88 %, and 6.09 %, respectively.