from first principles PP-I-1

PP-V-11Photocatalytic Degradation and Mineralization of Methylene Blue Dye ontoAg-Modified Natural Zeolite CatalystPode R., Manea F., Colar L.A., Jakab A.“Politehnica” University of Timisoara, Faculty of Industrial Chemistry and EnvironmentalEngineering, Timisoara, Romaniarodica.pode@chim.upt.roDyes are characterized by complex aromatic molecular structures, which offerphysicochemical, thermal and optical stability. They may also be carcinogenic, mutagenic andhighly toxic to human beings [1,2] and need to be removed from industrial wastewaters. Thishas always been a major problem because can not be easily treated by conventional methods,i.e., coagulation, chemical flocculation or by biological procedures [3,4]. Also, conventionaloxidation treatment encounters difficulty to oxidize dyestuffs and complex structure oforganic compounds. In this study, the photodegradation and the mineralization of a MethyleneBlue (MB) cationic dye from aqueous solution was investigated, in the presence of hydrogenperoxide, using an Ag-modified natural zeolite catalyst (Z-Ag red ). The catalyst wassynthesized by a chemical activation prior to the ion exchange and followed by a silverreduction with sodium boron hydride. The photocatalytic performance of Z-Ag red catalyst wasproved by photocatalysis application without and in the presence of hydrogen peroxide for thedecolorisation, degradation and mineralization of MB dye containing wastewater undervisible irradiation. The effect of H 2 O 2 dose on the MB degradation and mineralizationefficiencies by photocatalysis on Z-Ag red highlighted that in the applied working conditions(initial MB concentration of 50 mg·L -1 , 1 g·L -1 catalyst dose at pH 9), 20 mM H 2 O 2 wassufficient to reach a high degradation efficiency and to achieve an effective mineralization.The kinetic study revealed that the photodegradation rate follows pseudo first order kinetics.The photocatalytic rate of MB significantly increased in the presence of hydrogen peroxide.The good results regarding the photocatalytic degradation and mineralization of MB dyeusing Z-Ag red catalyst claim it as a potential for the real photocatalysis application in MBcontainingwastewater under solar light.References:[1] C.A.P. Almeida, N.A. Debacher, A.J. Downs, L. Cottet, C.A.D. Mello, J. Coll. Interf. Science. 332(2009) 46.[2] M. Ertas, B. Acemioglu, M.H. Alma, M. Usta, J. Haz. Mat. 183 (2010) 421.[3] N. Sobana, K. Selvam, M. Swaminathan, Sep. Purif. Tech. 62 (2008) 648.[4] M. Muruganandham, M. Swaminathan, Dyes and Pigments. 68 (2006)133.320