RESUMO
Organic compound is the main pollutant in industrial effluent. Conventional wastewater treatment processes are inefficient for the removal of toxic or non-biodegradable organic pollutants. Advanced electrochemical depollution is a very efficient and economic method, suitable when the wastewater contains toxic and recalcitrant organic pollutants. The aim of the present study was to investigate the application of the electro-Fenton (EF) process for the degradation and mineralization of a stable oil-in-water emulsion (0.01% in v/v). The effects of operating parameters such as cathode material (graphite, Ti/Pt and steel), nature (Na2SO4, NaNO3 and NaCl) and dose of electrolyte (25-75â mM), initial ferrous ions concentration (1-75â mM), current intensity (0.1-0.2â A) and operating time, on chemical oxygen demand (COD) removal efficiency, were studied. Results showed that the EF method can be used efficiently for the degradation of stable cutting oil emulsion. For considered initial conditions (bubbling compressed air at 1â L/min, 0.15â A, pH 3, [Na2SO4]=0.05â M, [FeSO4]=0.015â M, COD0=400â mgâ O2/L), the best removal efficiencies were obtained under the following conditions: graphite as cathode material, 180â min for treatment duration and 0.05â M [Na2SO4]. For these conditions, treatment of 250â mL of emulsion led to 93.6% of cutting fluid mineralization, which correspond to 25â mgâ O2/L of final COD, 19â kWh/m3 of treated wastewater and 24.039â kWh/kg of COD removal.