Treatment of petroleum wastewater using combination of solar photo-two catalyst TiO2 and photo-Fenton process

Abstract

The objective of this study is to investigate the performance of employing Fenton’s reagent in the solar photo-catalyst of TiO2 to treat petroleum wastewater from Sohar oil Refinery, Oman. A central composite design (CCD) with response surface methodology (RSM) is applied to evaluate the relationships between operating variables, such as TiO2 and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following three responses prove to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), total organic carbon (TOC) and residual iron (Fe). The obtained optimum conditions include a reaction time of 90min, 0.66g/L TiO2, 0.5g/L H2O2, 0.01g/L Fe2+, and pH 4.18. TOC and COD removal rates are 62% and 50%, respectively, and 0.8ppm residual iron is obtained. The predictions correspond well with experimental results (TOC and COD removal rates of 64%, and 48%, respectively, and 0.5ppm residual iron). The solar photo-Fenton process has well efficient for petroleum wastewater treatment in acidic conditions pH<7 and more economic by free energy.