Removal of benzene from wastewater via Fenton pre-treatment followed by enzyme catalyzed polymerization

摘要

This study investigated the feasibility of a two-step process for the removal of benzene fromnbuffered synthetic wastewater. Benzene is outside the scope of enzymatic removal. In order tonremove it from wastewater using enzyme, its pretreatment by modified Fenton reaction wasnemployed to generate the corresponding phenolic compounds. In the first phase, the optimumnpH, H2O2 and Fe2t concentrations and reaction time for the Fenton reaction were determinednto maximize the conversion of benzene to phenolic compounds without causing significantnmineralization. The pretreatment process was followed by oxidative polymerization of the phenolicncompounds catalyzed by a laccase from Trametes villosa. Factors of interest for the three-hournenzymatic treatment were pH and laccase concentration. Under optimum Fenton reactionnconditions, 80% conversion of the initial benzene concentration was achieved, giving a mixturencontaining oxidative dimerization product (biphenyl) and hydroxylation products (phenol, catechol,nresorcinol, benzoquinone and hydroquinone). Enzymatic removal of biphenyl and benzoquinonenwas not possible but 2.5 U/mL laccase was successful in removal of the rest of the phenolicnproducts.