Electro-oxidation of woodworking wastewater by using boron-doped diamond electrode

The electrocatalytic degradation efficiency of boron-doped diamond (BDD) anode was evaluated for oxidation of chemically pretreated woodworking effluent. Impacts of different experimental parameters including current density (27–106 mAcm-2), initial pH (3–9.5), electrolyte type (NaCl, Na2SO4 and Na2S2O8) and electrolyte concentration (1–2 g NaCl/500 ml) were tested in the study. Process efficiency was evaluated by monitoring variations in total organic carbon (TOC), chemical oxygen demand (COD) and energy cost. The degradation process was fitted well with pseudo first-order kinetics. The higher values of applied current density indicated a mass-transport controlled degradation. Maximum levels of current density (106 mAcm−2) and oxidation period (480 min) with addition of 2 gr NaCl/500 ml electrolyte the highest removal efficiencies for COD (97%) and TOC (97%). However, high current density and prolonged oxidation period resulted high energy consumption (779 kWh per kg CODremoval). When experimental conditions were optimised considering both removal efficiency and energy consumptions (current density of 45 mAcm−2, pH 7.0, 2.0 g NaCl/500 ml and oxidation period of 480 min), degradation efficiency of 93% was achieved by only 239 kWh per kg CODremoval energy consumption. Overall results of the study demonstrated BDD electrode has a promising potential for degradation of woodworking effluents with strong electrocatalytic impact.