Photocatalyzed ozonation by Ce doped TiO2 catalyst degradation of pesticide Dicamba in water

BACKGROUNDThe photocatalyzed and ozonated degradation of a widely used pesticide, Dicamba, was studied using Ce loaded on titania as photocatalyst under visible light. The work is aimed at reducing environmental pollution by pesticides. Photocatalysts are important because they have many advantages: noncorrosive, environmentally benign and fewer disposal problems. They are also much easier to separate from liquid products and can be designed to give higher activity and longer catalyst lifetimes. This work aims to develop a novel method for degradation and mineralization of pesticides using a heterogeneous photocatalyst. RESULTSCe/TiO2 photocatalysts with metal loadings zero, 0.25, 0.50 and 1% wt% on TiO2 were synthesized using a wet-impregnation technique and characterized by XRD, UV-DRS, BET, TEM, SEM-EDX, FT-IR and ICP analyses. Photocatalyzed ozonation with 1%Ce/TiO2 yielded 100% degradation and mineralization of Dicamba (3,6-dichloro-2-methoxybenzoic acid) in 2h under basic pH conditions. The aggregate of degradation of pesticide and mineralization were monitored by GC-MS. For 20mgL(-1) Dicamba, 0.1gL(-1) of catalyst was found to be the optimum to generate small chain aliphatic acids and mineralization. Results show that photocatalyzed ozonation of Dicamba with Ce/TiO2 catalyst is a very practical means for its degradation. CONCLUSIONSThe synthesized heterogeneous photocatalyst had high catalytic activity for the degradation of Dicamba pesticide. The catalyst is fully recoverable and reusable multiple times with no loss of activity. (c) 2014 Society of Chemical Industry