Investigating the influences of electrode material property on degradation behavior of organic wastewaters by iron-carbon micro-electrolysis

The degradation of Sunset Yellow (SY) wastewater was carried out using Fe-C micro-electrolysis process under the optimal conditions: initial pH 6, Fe/C ratio 1:1, Fe/C total mass 500 g.L-1 and the air flow rate 45 L.h(-1). Effects of particle size, particle shape and material species of activated carbon (AC) on degradation and chemical oxygen demand (COD) removal efficiencies of SY by the Fe-C micro-electrolysis process were studied. The degradation and COD removal efficiencies of 500 mg.L-1 SY were approximately 99.0% and 77.5% after 90 min treatment with 3-6mm spherical coal-based AC particles. Additionally, the degradation and COD removal efficiencies of SY maintained over 99.0% and 65.0% after 90 min treatment with any other types of AC. The stability of the Fe-C micro-electrolysis process was preferably and the AC surfaces before used and after used for 20 times were characterized by SEM, XPS, and XRD. In addition, the decomposition and degradation process was determined by UV-Vis analysis of the treated SY wastewaters. In conclusion, the particle size, particle shape and material species of AC indeed have influences on the degradation and COD removal efficiencies of SY by the Fe-C micro-electrolysis process and 3-6mm coal-based spherical AC was selected as the optimal electrode material. Moreover, the antibiotic and printing wastewaters were selected to investigate the feasibility of degradation of other refractory organic wastewaters by Fe-C micro-electrolysis process.