Research on the Application of Laccase to the Treatment of Oily Wastewater

The feasibility of using laccase to treat oily wastewater was examined. When only laccase was added to the synthetic oily wastewater, the suitable technological conditions were laccase at 3 U/mL, pH at 6.0, a temperature of 30°C, and a reaction time of 6 h for the initial oil concentration of 120 mg/L. Under those conditions, the rate of oil removal was as high as 69%. The effects of Mg2+, Mn2+, Cu2+, and Fe2+ ions in wastewater on the rate of oil removal using laccase were investigated. The results showed that Cu2+and Fe2+ ions obviously inhibited the catalytic performance of laccase under the studied concentration. On the other hand, Mg2+ and Mn2+ ions only had slight effects on the rate of oil removal for the range of concentrations studied. A 95% oil removal rate could be obtained when actual wastewaters were treated using laccase with the additive chitosan under the suitable technological conditions.