ELECTROCHEMICAL OXIDATION OF PHTHALIC ANHYDRIDE IN AQUEOUS MEDIUM BY ELECTRO-FENTON PROCESS

摘要

Degradation of phthalic anhydride, a chemical widely used as plasticizer was studied in aqueous medium of pH 3 by the electrochemical advanced oxidation process "electro-Fenton" using carbon-felt cathode. This process generates in aqueous medium and in a catalytic way hydroxyl radicals, a powerful oxidant species for the oxidation of organic pollutants. The kinetics of the oxidative degradation of phthalic anhydride and the mineralization efficiency of the process were investigated through the effect of some operating parameter such as solution pH, applied current and catalyst concentration. The values of pH 3, applied current of 300 mA and Fe~(3+) concentration of 0.2 mM were found as optimum operating parameters. Kinetic data evidence a pseudo first-order reaction between hydroxyl radical and phthalic anhydride with an absolute rate constant of 9.1 × 10~8 M~(-1) s~(-1). Mineralization of phthalic anhydride aqueous solution was followed by the total organic carbon analysis and a mineralization degree of 97% was reached at the end of 8 h of electrolysis. The optimum operating conditions were applied to treatment of an industrial effluent from a Tunisian plastic manufacturing plant.