Sequential electrochemical/biological treatment for the removal of 2,6-dichlorophenol from synthetic wastewater

The paper examines the effect of chloride on the oxidation of 2,6-dichlorophenol (DCP) performed at TiO2/RuO2 DSA anodes, which are specific catalysts for chlorine evolution. The results indicate that chlorine/hypochlorite originating from chloride oxidation in certain favourable conditions reacts with the organic substrate at the diffusion layer near the anode, accelerating the mass transfer of the reactant towards the electrode surface. When the bulk concentration of organic substrate has become very low, the oxidising species can accumulate in the bulk solution where the accomplishment of the oxidation of residual reactant and of its intermediates takes place. Solutions which also contained glucose were electrolysed in order to verify the high level of selectivity of DCP oxidation with respect to a biodegradable substrate: glucose was found to be unchanged up to nearly complete elimination of DCP. The toxicity of the solution was sufficiently reduced to reach values compatible with the subsequent biological treatment.