Evaluating the TiO2 as a solar photocatalyst process by response surface methodology to treat the petroleum waste water

Abstract

The aim of this study is to investigate the performance of employing the solar photo-catalyst of TiO2 to treat petroleum wastewater from Sohar oil Refinery (SOR), evaluate the performance of employing this process by a central composite design (CCD) with response surface methodology (RSM) and evaluate the relationships among operating variables such as TiO2 dosage, pH, C0 of COD, and reaction time to identify the optimum operating conditions. Quadratic models prove to be significant with very low probabilities (<0.0001) for the following two responses: total organic carbon (TOC) and chemical oxygen demand (COD).TiO2 dosage and pH are the two main factors that improved the TOC and COD removal while C0 of COD and reaction time are the actual factors. The optimum conditions are a TiO2 dosage (0.6 g/L), C0 of COD (1600 ppm), pH (8), reaction time (139 min) in this method. TOC and COD removal rates are 15.5% and 48.5%, respectively. The predictions correspond well with experimental results (TOC and COD removal rates of 16.5%, and 45%, respectively). Using renewable solar energy and treating with minimum TiO2 input make this method to be a unique treatment process for petroleum wastewater.