High efficient treatment of the petrochemical phenolic effluent using spent catalyst: Experimental and optimization

Phenol is one of the dangerous volatile organic compounds (VOCs) which presents in almost every petrochemical plant's effluent. In this study, we regenerated spent catalyst of petrochemical styrene unit and applied to remove phenol from an industrial phenolic effluent in Fenton-like process. The catalyst was characterized using SEM, XRD, N2 adsorption-desorption, EDX and XRF techniques. Effects of four important variables including H2O2 concentration, catalyst amount, temperature and reaction time on the phenol removal efficiency were evaluated and optimized using Response Surface Methodology (RSM) based on central composite design (CCD). The developed model predicted the removal efficiency with high accuracy (R2 = 0.99). The optimum operational conditions were 47.1 °C, 0.16 mol L−1 H2O2, 20 g L−1 of catalyst and 92 min which resulted in the maximum removal efficiency (98.5%). Fenton-like oxidation process was at effluent neutral pH over the regenerated catalyst. The reported efficiency is sufficient to discharge the effluent in surface waters.