Treatment of aqueous pentachlorophenol by horseradish peroxidase and hydrogen peroxide

This study focused on the oxidation and subsequent polymerization and preci pitation of pentachlorophenol (PCP) under the combined action of hydrogen p eroxide and horseradish peroxidase (HRP); HRP was capable of catalyzing the oxidation and detoxification of 0.05 mmol PCP prepared in distilled/deioni zed water. The optimal pH for PCP transformation was in the rang 4-5. PCP r eacted with peroxide with a stoichiometry of 2:1. Stoichiometric and chlori de production studies indicate that the main products gene-related in the P CP treatment process are dimers. The residual toxicities of treated solutio ns were higher than could be accounted for by residual PCF. It was conclude d that unidentified soluble products contribute to this excess toxicity. In contrast to previous studies of the treatment of various phenols, neither polyethylene glycol nor chitosan were effective in reducing HRP dose requir ements nor in enhancing toxicity removal during PCP treatment. (C) 2000 Els evier Science Ltd. All rights reserved.