Resumo

VELA-MONROY, Cindy A.; SAAVEDRA-ALEMAN, Martha J.  e  CARRIAZO-BANOS, José G.. Homogeneous and heterogeneous catalysts of Fe³⁺, Co²⁺ and Cu²⁺ for the degradation of methyl parathion in diluted aqueous medium. TecnoL. [online]. 2016, vol.19, n.37, pp.13-28. ISSN 0123-7799.

Degradation of pesticides (plaguicides, herbicides, fungicides, among others) in aqueous media is a subject of great importance for ensuring the water quality into numerous hydric sources. This work reports the assessment of homogeneous (metal ion solutions) and heterogeneous (oxides supported on alumina) systems that are based on Fe³⁺, Co²⁺ y Cu²⁺, which were used as catalysts for oxidation (degradation) of methyl parathion (a plaguicide) in aqueous solution. Hydrogen peroxide was herein used as oxidizing molecule under mild condition of reaction (25 ºC and atmospheric pressure). The solids were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Fe³⁺/H₂O₂ (Fenton system) was the most active homogeneous catalyst compared to Co²⁺/H₂O₂ and Cu²⁺/H₂O₂ systems. Solids catalysts such as cobalt, copper or iron oxides as well as mixed oxides supported on alumina were active at pH close to neutrality. Fe-Co-Cu/Al₂O₃, Co-Cu/Al₂O₃ and Fe-Co/Al₂O₃ mixed systems were solids with the highest catalytic activity. In addition, an important effect of the support (d-Al₂O₃) on the reaction pH was observed, allowing to reach values close to that of the neutrality, and thus increasing the catalytic activity of both cobalt oxide and copper oxide species. These results allow advancing on a new pathway for searching catalysts to remove organophosphorous pesticides from residual waters.

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