International Science Community Association Research Journal of Recent Sciences 2277 - 2502 2 ISC-2012 2013 February 2 Periodic Change in the Concentration of Hydrogen peroxide Formed during the Semiconductor Mediated Sonocatalytic treatment of Wastewater: Investigations on pH Effect and Other Operational Variables 136 149 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 Lakdawala M.M. 1 Chemistry Department, S P T Arts and Science College, Godhra, Gujarat, INDIA Lakdawala J.M. 2 Prime interior, Vapi, Gujarat, INDIA Rojith G. 1 School of Environmental Studies, Cochin University of Science and Technology, Cochin, Kerala, India BrightSingh I.S. 2 Ariponnammal S. 1 Department of Physics, Gandhigram Rural Institute, Deemed University, Gandhigram, Dindigul District, TamilNadu, INDIA Srinivasan T. 2 Ariponnammal S. 1 Department of Physics, Gandhigram Rural Institute, Deemed University, Gandhigram, Dindigul District, Tamil Nadu, INDIA Martínez-Hilders Andrea 1 Departamento de Ciencias Biológicas, Decanato de Agronomía, Universidad Centroccidental Lisandro Alvarado, Barquisimeto, VENEZUELA Mendoza Yuraima 2 Peraza Dasybel 3 Laurentin HernÃn 4 Shukla Niharika 1 Department of Genetics and Plant Breeding, Jawaharlal Nehru Agricultural University Jabalpur, INDIA Nannu Shafakatullah 1 Department of Bio-Sciences, Mangalore University, Mangalagangothri, Karnataka, INDIA Shetty Sowmyashree 2 OrisonLobo Reema 3 Krishnamoorthy M. 4 Prasad Chandan 1 Dept. of Chemistry, D.A.V College, Kanpur, INDIA Mishra R.P. 2 R and D Division, MRD Life Sciences, Lucknow, INDIA Ali Asif 3 Integral University, Lucknow, INDIA Gangwar V.S. 4 Dept of Chemistry, V.S.S.D College, Kanpur, INDIA Chand Shweta 5 Dept of Chemistry, Christ Church College, Kanpur, INDIA Maru R.N. 1 JJT University, Rajasthan, INDIA Patel R.S. 2 Department of Biology, KKSJ Maninagar Science College, Ahmedabad, Gujarat, INDIA Jyothi K.P. 1 School of Environmental Studies, Cochin University of Science and Technology, Kochi, INDIA Sindhu Joseph 2 Suguna Yesodharan 3 Yesodharan E.P. 4 > Research Paper 2012 7 31 2013 February 2 Hydrogen peroxide, formed in situ or externally added, is an important Reactive Oxygen Species (ROS) involved in Advanced Oxidation Processes (AOP) such as sono, photo and sonophoto catalysis being investigated as environment friendly technologies for the treatment of wastewater under ambient conditions. Among the various ROS such as .OH, HO2., O2- ., H2O2, O2 etc, H2O2 is the most stable and it serves as a reservoir of other ROS. Current investigations on the ZnO and TiO2 mediated sonocatalytic degradation of phenol pollutant in water reveal that, H2O2 formed cannot be quantitatively correlated with the degradation of the pollutant. The concentration of H2O2 varies in a wavelike fashion (oscillation) with well defined crests and troughs, indicating concurrent formation and decomposition. Both processes are sensitive to the reaction conditions and depending on the externally forced or in situ situation, either of them can predominate. The degradation of H2O2 continues for some more time even after the sonication has been put off showing that the catalyst has some residual activity. This further confirms that trapped electrons and holes have unusually longer life even after the irradiation is off. Concentration of H2O2, catalyst loading, dissolved gases, concentration of the organic pollutant, pH etc influence the oscillation. The degradation of phenol is favored in the acidic range with maximum at pH 5.5. The successive maxima and the minima in the oscillation of H2O2 concentration also are higher in the acidic range. The influence of pH on various factors leading to the oscillation in the concentration of H2O2 is unequivocally established from a number of experiments, for the first time in this paper. An appropriate mechanism to explain the complex phenomenon is also proposed. Copyright@ International Science Community Association