Abstract:
This work presents experimental results on the treatment of a synthesized wastewater by means of photocatalytic Advanced Oxidation Process (AOPs) constituted by a combination of a single oxidant. The experiment was conducted with the presence of UV light, TiO2 catalyst and H2O2 oxidant in a batch recycle reactor. The total volume of the reactor was 250 mL with 55.8 mL of the effective annular volume of a photoreactor. Fluid inside photoreactor was irradiated by 254 nm, 6W ultraviolet light. Each experiment was conducted for 120 min accompanied by total carbon and HPLC analysis. The feed wastewater was prepared from D – Glucose anhydrous (C6H12O6), Sodium hydrogen carbonate (CHNaO3), Potassium hydrogen carbonate (CHKO3), Ammonium hydrogen carbonate (CH5NO3), Peptone and Lab Lemco, with initial total carbon 1080 mg L-1. The effect of reagents’ initial concentration on total carbon removal was studied to derive the optimum operating conditions. As a result, obtained initial total carbon concertation was found to be 32 mg L-1. The optimum amount for TiO2 loading was 0.5 g L-1 with 58% TC removal and 53% with 66.6 mg L-1 H2O2. Addition of both reagents to process, catalyst, and oxidant, did not result in better performance, only 52% total carbon removal was observed. Besides, the effect of phenolic compound presence on the photocatalytic treatment of synthesized wastewater was examined. Experiments were conducted for phenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and 4-nitrophenol at 5 ppm and 10 ppm concentrations. The conversion of the model compound was always higher than corresponding total organic carbon removal, whereas introduction of H2O2 led to higher total carbon removal and higher phenolic compound decomposition. Synthetic wastewater with 10 ppm phenol, keeping 32 mg L-1 initial TC concentration, treated by UV/TiO2 showed 48% TC and 98% phenol removal, while the H2O2 addition markedly enhanced the process obtaining 100% phenol removal after 45 minutes and 80% TC removal. Results for 10 ppm 2-chlorophenol with the only TiO2 demonstrated 81% total carbon removal with the complete decomposition of 2-chlorophenol. Results of TC removal were also obtained for 2,4-Dichlorophenol at 5 ppm, 10 ppm and with the addition of H2O2, 40%, 59%, and 88%, respectively. 2,4-DCP oxidation was 91% at 5 ppm concentration, 95% at 10 ppm and 100% in the presence of hydrogen peroxide. For 2,4,6-Trichlorophenol, TC conversion at 5 ppm was 36%, at 10 ppm was 44% and 83% with H2O2, and 100% of 2,4,6-TCP oxidation by the end process. 4-Nitrophenol also degraded entirely after 120 minutes and resulted in 84% conversion of TC at 10 ppm concentration with process containing H2O2 and catalyst.