ADVANCED OXIDATION PROCESS FOR TREATMENT OF AQUEOUS SOLUTION CONTAINING POLYCYCLIC AROMATIC HYDROCARBONS (PAHS)

Polycyclic Aromatic Hydrocarbons (PAHs) is a type of persistent organic pollutant that categorized by United States Environmental Protection Agency (USEPA) as toxic, carcinogenic and mutagenic. The presence of PAHs in aquatic environment poses harmful effect to the aquatic life as well as the human beings due to the bioaccumulation in the food chain that can lead to cancer and birth defect. The advanced oxidation process- UV/H2O2 system had been adopted and carried out for the treatment of PAHs in the aqueous solution by many researchers. However, the optimization of the process for treatment PAHs had not yet been reported. In this study, the performance of the process was assessed by carrying out preliminary experiments and optimized by response surface methodology (RSM). The synthetic water sample was prepared by diluting the 16 PAHs standard solution mix in deionized water. The preliminary experiments were carried out to determine the range of the operational variables- H2O2 concentration, pH and reaction time. The maximum COD removal achieved in preliminary experiment was 71.5% under the operating condition of 1mM H2O2 concentration, pH of 3.5 and 90 minutes reaction time. The Design Expert Software was utilized for the optimization of the UV/H2O2 system by RSM based on five-level central composite design (CCD). The ranges for RSM were 1-3 mM for H2O2 concentration, 2-5 for pH and 30-90 minutes for reaction time. The quadratic equation fitted the model well and was found to be significant and adequate by ANOVA analysis and diagnostics plots. The optimum operating condition which achieved COD removal efficiency of 79.78% were H2O2 concentration of 1mM, pH of 3.5 and reaction time of 90 minutes. The experimental data and model prediction agreed well with error less than 3%. The PAHs removal efficiency was 84.28%. The study revealed that the UV/H2O2 process is effective for treatment of PAHs in aqueous solution and the process can be optimized by RSM.