219 J. Indian Chem. Soc., Vol. 92, February 2015, pp. 219-222 Treatment of petroleum industry wastewater using TiO 2 /UV photocatalytic process Niraj S. Topare*, Martin Joy, Ratnadeep R. Joshi, Pradeep B. Jadhav and Lalitkumar K. Kshirsagar Department of Petroleum & Petrochemical Engineering, Maharashtra Institute of Technology, Paud Road, Kothrud, Pune-411 038, Maharashtra, India E-mail : niraj.topare@mitpune.edu.in, nirajtopare06@gmail.com Manuscript received online 09 July 2014, revised 01 August 2014, accepted 16 August 2014 Abstract : In the present study, degradation of petroleum industry wastewater has been investigated through laboratory experiments by employing heterogeneous photocatalytic process. A photocatalytic reactor was used for the advanced oxi- dation. The industrial wastewater was characterized. Photocatalytic activity of semiconductor such as titanium dioxide (TiO 2 ) has been investigated. An attempt has been made to study the effect of process parameters through amount of catalyst, and operating pH on photocatalytic degradation of petroleum industry wastewater. The experiments were car- ried out by varying pH (2–11), amount of catalyst (0.25–1.5 g/L). Optimal suspended catalyst concentration, fluid pH and temperature were obtained at amounts of near 1 g/L, 3 and 50 ºC, respectively. The maximum rate of degradation was observed in acidic medium at pH 3 and maximum reduction in chemical oxygen demand (COD) of 60%. Keywords : Wastewater, photo-catalysis, photocatalytic degradation, COD, TiO 2 . Introduction Huge amounts of water are used in a petroleum refi- nery and, consequently, significant volumes of wastewa- ter are generated. The traditional treatment of refinery wastewater is based on the physicochemical and mechanical methods and further biological treatments in the integrated activated sludge treatment units. The contamination of water supplies by organic molecules is an increasing prob- lem mainly because many of these molecules are not readily degraded by conventional methods for the treatment of effluents 1 . Besides causing visual pollution, this kind of pollutant has high levels of toxicity, non-biodegradability and resistance to destruction 2 . Several solutions are pro- posed in this regard, including use of coagulation en- hanced by centrifugation, ultra filtration 3 or sorption on organ minerals 4 with a level of advantage for each. These methods are not efficient and cost effective for wastewa- ters containing high concentration of more toxic pollut- ants. This requires some novel techniques to transfer the highly toxic pollutants chemically into benign species. Advanced oxidation processes (AOPs) are more efficient, cheap, and ecofriendly in the degradation of any kind of toxic pollutants. These processes can completely degrade the organic pollutants into harmless inorganic substances such as CO 2 and H 2 O under moderate conditions. AOPs generate hydroxyl radical, a strong oxidant, which can completely degrade or mineralize the pollutants non-se- lectively into harmless products 5 . Titanium dioxide (TiO 2 ) is generally considered to be the best photocatalyst and has the ability to detoxificate water from a number of organic pollutants. However wide- spread use of TiO 2 is uneconomical for large-scale water treatment, thereby interest has been drawn toward the search for suitable alternatives to TiO 2 6 . Many attempts have been made to study photocatalytic activity of diffe- rent semiconductors such as SnO 2 , ZrO 2 , CdS and Nb 2 O 5 7 , compared the photocatalytic activity of TiO 2 , SnO 2 , ZnS, Nb 2 O 5 and CdS for the degradation of petro- leum wastewater and found TiO 2 to be the most effective catalyst. Experimental Chemicals : Titanium dioxide (99.7%) was used as a photo cata- lyst and purchased from Molychem, India. The wastewa- ter was collected from petroleum industry. Distilled wa-