عنوان مقاله [English]
In this research, horseradish peroxidase for phenol removal was utilized. First, the process was studied at the laboratory scale using a synthetic phenol solution (1-10) mM. Results showed that horseradish peroxidase (HRP) could effectively remove phenolic compounds from wastewater and that the catalytic capability of the enzyme was maintained for a wide range of pH, temperature, and aromatic concentration levels. The performance conditions were optimized for at lease 95% and 100% removal of phenolic compounds for both actual and synthetic wastewaters under high and low phenol concentrations (1 and 10 mM). The phenolic wastewater used was an olive mill effluent with a phenol concentration of 1221 mg/L (13 mM) and a pH value of 3.5. At the end of the reaction, the phenolic compounds changed to insoluble polymers and precipitated. Each enzyme/wastewater system was optimized for the following chemical dosages: hydrogen peroxide, enzyme, polyethylene glycol (PEG), and buffer. Furthermore, the reaction time to achieve at least 95% phenol removal was determined. According to the results, COD and BOD reduced to 58% and 78%, respectively. Experimental results showed an increase in H2O2 concentration beyond the optimum dose resulting from enzyme inactivation, thus reducing the phenol removal efficiency. On the other hand, increasing the enzyme, PEG, and/or reaction time beyond the optimum values resulted in only a marginal increase in removal efficiency.