ELECTROCHEMICAL DETOXIFICATION OF A 1,4-BENZOQUINONE SOLUTION IN WASTE-WATER TREATMENT

The electro-oxidation of 1,4-benzoquinone in water solution was investigated. The benzoquinone concentration, intermediate products, DOC, COD and the toxicity of the oxidized solution was monitored during oxidation with Ti/IrO2 and Ti/SnO2 anodes (in the following text: IrO2 and SnO2 anodes). It was found that the most important parameter is the nature of the anode. With the IrO2 anode the primary oxidation was attained, i.e. benzene ring rupture occurred, resulting in an accumulation of carboxylic acids formation as final non-toxic products. With the SnO2 anode, the carboxylic acids are formed in a much faster reaction and then oxidized, giving only CO2 as the final product. The detoxification of benzoquinone solution using both electrodes was determined in the course of the reaction by the Microtox test, activated sludge respirometric test and were also predicted using a developed formula. Calculated average toxicity, knowing the chemical composition of the oxidized solution, DOC and individual EC(50)s of the components were in agreement with observed values. The biodegradability of compounds in the solution at the end of electrolysis with the IrO2 anode was demonstrated.