International Science Community Association Research Journal of Recent Sciences 2277 - 2502 2 ISC-2012 2013 February 2 Influence of Reaction Intermediates on the Oscillation in the Concentration of insitu formed Hydrogen peroxide during the Photocatalytic Degradation of Phenol Pollutant in Water on Semiconductor Oxides 82 89 EN Ahirwar J.R. 1 Department of Botany, Govt. College Niwari, District-Tikamgarh, M.P. INDIA Erhabor J.O. 1 Departement of Plant Biology and Biotechnology, University of Benin, P.M.B 1154, Benin City, NIGERIA Idu M. 2 Benson Idahosa University, PMB, 110, Benin City, NIGERIA Udo F.O. 3 Mehta Kavit 1 Mehsana Urban Institute of Sciences, Ganpat University, Ganpat Vidyanagar, Kherwa, Dist. Mehsana, North Gujarat, INDIA Patel B.N. 2 M.G. Science Institute, Navrangpura, Ahmadabad, INDIA Jain B.K. 3 Mishra Bishwambhar 1 Instrumental and Food Analysis Laboratory, School of Bio Sciences and Technology, VIT University, Vellore, Tamil Nadu, INDIA Suneetha Vuppu 2 Surekha M. 1 Toxicology Laboratory, Department of Botany, Kakatiya University, Warangal, Andhra Pradesh, INDIA Kiran S. 2 Naresh A. 3 Reddy S.M. 4 Krishania Suman 1 Department of Life Sciences,The IIS University, SFS Mansarovar, Jaipur -20 (Raj) INDIA Agarwal Kalpana 2 Kelkar TusharS. 1 Environmental Sciences Research Laboratory, Department of Botany, Wilson College, Mumbai, INDIA Bhalerao SatishA. 2 Naina Thangaraj 1 School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, INDIA Sharan Siddharth 2 Vuppu Suneetha 3 Javed Ahmad 1 Department of biochemical Engineering and Food Technology, Harcourt butler technological Institute, Kanpur, INDIA Khan Iffat 2 Department of Bioscience, Integral University Lucknow, INDIA Ashfaq Ahmad 3 kaushar Imam 4 Dubey S. 1 MVJ College of Engineering, Bangalore, Karnataka, INDIA. Kherwa V. 2 Department of Chemistry, C.D.L.University, Sirsa 125055, Haryana, INDIA. Kherwa V. 1 Department of Chemistry, C.D.L. University, Sirsa 125055, Haryana, INDIA Dubey S. 2 Department of Chemistry, MVJ College of Engineering, Bangalore, Karnataka, INDIA PatelKetan B. 1 Government Science College, Department of Chemistry, Gandhinagar, Gujarat, INDIA Patel YogeshM. 2 Patel RakshaB. 3 Udaykumar P. 1 Department of Chemistry, Birla Institute of Technology and Science, Pilani – K.K. Birla Goa Campus, Zuarinagar, Goa, INDIA Khanna T. 2 Behera R.N. 3 Hassan S.Z. 1 Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, INDIA Chopade S.A. 2 Vinjamur M. 3 LalMohan 1 Department of Chemistry, Jai Narain Vyas University, Jodhpur, Rajasthan, INDIA Gangotri K.M. 2 Sindhu Joseph 1 School of Environmental Studies, Cochin University of Science and Technology, Kochi 682022, INDIA Jyothi K.P. 2 SujaP. Devipriya 3 Suguna Yesodharan 4 Yesodharan E.P. 5 > Research Paper 2012 7 31 2013 February 2 Phenols are common pollutants in many petrochemical industry wastewaters. Due to the stability of the aromatic ring their destruction requires extreme conditions. Photocatalysis using semiconductor oxides as catalysts is found to be an effective Advanced Oxidation Process (AOP) for the mineralisation of phenol. The degradation proceeds through the formation of various intermediates which eventually get mineralized to yield CO2 and H2O. The intermediates identified are hydroquinone, catechol, and benzoquinone which are formed by the interaction of photogenerated OH radicals with phenol. These intermediates do not accumulate beyond a particular concentration even though the phenol degradation continues unabated. The insitu formed H2O2 concentration increases and decreases periodically in a wave like fashion indicating concurrent formation and decomposition. Externally added H2O2 enhances the degradation rate of phenol initially due to the generation of more reactive OH radicals by inhibiting the recombination of photogenerated electrons and holes as well as by its own self decomposition. Externally added catechol and hydroquinone inhibit the degradation of phenol initially. However their influence on the fate of H2O2 is not quite significant. The study also shows that the formation/decomposition of H2O2 is concentration dependent and after the initial build up, the formation or decomposition takes precedence depending on the concentration and composition of the reaction system. Possible reasons for the observed phenomenon are analysed and a mechanism is proposed. Copyright@ International Science Community Association