Comparison of alternative treatments for 4-chlorophenol removal from aqueous solutions: use of free and immobilized soybean peroxidase and KrCl excilamp.

The removal of 4-chlorophenol (4-CP) from industrial wastewater continues to be an important environmental issue and some interesting results have been obtained using oxidoreductive enzymes such as peroxidases and UV, generated by novel excilamps. In this study enzyme (free and immobilized soybean peroxidase) and UV (produced by a KrCl excilamp) were used to treat 4-CP solutions at concentrations ranging from 50 to 500 mg L(-1). It was shown that the excilamp can facilitate higher removal efficiencies in all cases with complete 4-CP elimination taking place between 5 and 90 min. The enzyme removed approximately 80% of the 4-CP concentrations in both the free and immobilized state up to concentrations of 250 mg L(-1). At 500 mg L(-1) the immobilized system shows much higher removal efficiency due to increased enzyme stability in the presence of higher formation of by-products.