Agradecimentos: The authors wish to thank the Brazilian funding agencies CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), FUNDECT (Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado...

Agradecimentos: The authors wish to thank the Brazilian funding agencies CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), FUNDECT (Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul) and INCT-EMA (Instituto Nacional de Ciência e Tecnologia de Estudos do Meio Ambiente). The authors also thank the Ministry of Science and Innovation of Spain (projects CTQ2011-26258 and NOVEDAR 2010 CSD2007-00055) and AGAUR - Generalitat de Catalunya (project 2009SGR 1466) for funds received to carry out this work

Abstract: In photocatalysis, controversy still exists over as whether oxidation proceeds via primary oxidants, such as HOradical dot radicals, positive holes, electrons, O2radical dot- radicals in the photodegradation process. The contribution of the main active species to the photocatalytic...

Abstract: In photocatalysis, controversy still exists over as whether oxidation proceeds via primary oxidants, such as HOradical dot radicals, positive holes, electrons, O2radical dot- radicals in the photodegradation process. The contribution of the main active species to the photocatalytic degradation of metoprolol (MET) using a solar simulator with Xenon lamp as irradiation source was examined by using different specific scavengers (formic acid, tert-butyl alcohol, ro-benzoquinone and oxygen). According to this, we also compared the effect on the generation of active species, in the MET degradation, of two types of TiO2 catalyst having different physical and chemical properties: pure TiO2 and TiO2 doped with 5% B (w/w), both synthesized by sol-gel method. The scavenger study indicates that HOradical dot radicals are the dominant reactive species, contributing around 80% and to a lesser extent by the contribution of O2radical dot- radicals and holes in systems using TiO2 doped with 5% B (w/w). However, when pure TiO2 was used as catalyst, experiments carried out in ro-benzoquinone demonstrate that O2radical dot- radicals did not participate in the degradation mechanism of MET. Oxygen seems to play an important role during the observed degradation of MET. Additionally, the relation between the intermediates formed during the photocatalytic degradation with TiO2 doped 5% B (w/w) as catalyst, with addition of specific scavengers, was investigated and distinct degradation pathways have been proposed for each active species involved. By-products studies in the presence of scavengers were used as a diagnostic tool for the analysis of the photocatalytic mechanism and it was possible to prove that there is change in the reactions of the degradation process of MET when change the role of any active species generated on the surface of the catalyst

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES

FUNDAÇÃO DE APOIO AO DESENVOLVIMENTO DO ENSINO, CIÊNCIA E TECNOLOGIA DO ESTADO DE MATO GROSSO DO SUL - FUNDECT

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