Treatment of a Synthetic Phenolic Mixture by Electrocoagulation Using Al, Cu, Fe, Pb, and Zn as Anode Materials

Phenolic compounds constitute an important source of pollution causing severe environmental threats in countries that produce olive oil. The efficiency of five metal anodes (Al, Cu, Fe, Pb and Zn) was tested in an electrocoagulation system, in order to purify a phenolic-simulated effluent. Among them, Zn anode was found to be promising, because 86% of the total phenolic content and 49% of chemical oxygen demand was removed after 180 min of treatment within the operational conditions used (pH = 3.0, current intensity = 0.4 A, [NaCl] = 1.5 g/L, intergap distance = 1.0 cm, effective anodic area = 33.5 cm(2)). The biodegradability of the mixture was assessed by measuring the ratio BOD5/COD before and after each treatment, as well as the ecological impact through Vibrio fischeri bacteria. The electrical energy consumption varied between 8-14 kWh/m(3). The results also point out that during the treatment process, beyond the electrocoagulation route, the electrooxidation of organic compounds is also expected to occur.