The electrocatalytic activity of bare and 2-ethyl anthraquinone-modified graphite felt (2-EAQ/GF) toward oxygen reduction was investigated using a cyclic voltammetry technique in a neutral solution. The prepared cathodes were tested for electrogeneration of H2O2 and electro-Fenton oxidation (EFO) treatment of neutral coking wastewater (CW) after biological process, using a graphite anode and Fe-zeolite Y catalyst. The results showed that (i) H2O2 yield and current efficiency greatly depended on cathodic potential and materials; (ii) hydroxyl radicals, generated from Fe-zeolite Y-catalyzed H2O2 decomposition, played a great role in EFO treatment, while anodic direct and indirect oxidation was insignificant; (iii) chemical oxygen demand, total organic carbon (TOC) and acute toxicity of wastewater decreased by 40–50, 30–40 and 50–60%, respectively, and biodegradability increased after 1 h of EFO treatment. Due to the free-pH adjustment, EFO presents a potential engineering application for advanced treatment of CW.
Keywords: anthraquinone cathode, coking wastewater, electro-Fenton, Fe-zeolite Y, hydroxyl radicals