ARRUDA, C. C. de

MOURAO, H. A. J. L.

RIBEIRO, C.

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Photocatalyst with magnetic properties applied in the degradation of pesticides.

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  Photocatalyst with magnetic properties applied in the degradation of pesticides. Henrique A. J. L. Mourão1,2 (PG), Cezar Carvalho de Arruda 3 , Caue Ribeiro1 1Embrapa Instrumentação Agropecuária. Rua XV de Novembro, 1452, São Carlos, SP. 2Departamento de Química, Universidade Federal de São Carlos. Rod. Washington Luiz km 235, São Carlos – SP. 3Departamento de Física, Universidade Federal de São Carlos. Rod. Washington Luiz km 235, São Carlos – SP.   Efficient management of water is an object of concern for sustainable economic development. Thus, the decontamination of water becomes important, and the processes in the range of UV light - Vis on the surface of semiconductors are reported as the most potential for  comerciallization1. Nanosized particles collaborate with high surface areas, however, lead to high costs of separation of the catalyst. A form of separate the nanoparticles is their association  with magnetically activite phases - such as Fe3O4 (magnetite)2. In this context, this work describes the synthesis of core-shell nanocomposites (TiO2 – coated ferrite) by the polymeric precursors method 3, with potential for using as catalyst in water decontamination. The Fe3O4 nanoparticles were prepared by the dissolution of salts (FeSO4 and Fe2(SO4)3, Synth) in an aqueous solution of citric acid (JT Baker) to 40oC, in molar proportion  citric acid: metal equal to 3:1. After dissolution, the mixture was polymerized by the addition of ethylene glycol (Synth), with molar ratio citric acid: ethylene glycol equal to 1:2. The solutions were treated at 450oC for 2 hours. The synthesis of nanoparticles of CoFe2O4 followed the same procedure, using salt as the precursor Co2+ acetate cobalt (Co (CH3COO)2, Merck). Because  of the greater stability of CoFe2O4 those nanoparticles where coated with TiO2 using the (Ti[OCH(CH3)2]4, Aldrich) as a precursor of the Ti, in mass ratios of 55,6:44,4; 38,5:61,5; 27,3:72,7 and 11,1:88,9 CoFe2O4:TiO2. The suspensions were treated to 450oC for 2 hours. The figure 2 shows the change in relative concentration of atrazine over time, degradation catalyzed by nanocomposites, compared to pure TiO2.  0 20 40 60 80 100 120 1400,450,500,550,600,650,700,750,800,850,900,951,00C/C 0Time (min)CoFe2O4:TiO2 11,1:88,9 27,3:72,7 38,5:61,5 55,6:44,4 TiO2/450°C  Figure 1: Profile of degradation of atrazine in UV.  The findings showed that the polymeric precursors method is feasible for the production of nanoparticles CoFe2O4@ TiO2, with potential for use to degradation of pesticides, through the preliminary assessment of the photolysis of pesticide atrazine. Keywords: Photocatalysis, titanium dioxide, magnetic oxide, pesticides. e-mail: mourão@cnpdia.embrapa.br  1CHIRON, S.; FERNANDEZ-ALBA, A.; RODRIGUEZ, A.; GARCIA-CALVO, E. Water Research, v. 34, n. 2, p. 366–377, fev. 2000.  2VAYSSIERES, L.; CHANEAC, C.; TRONC, E.; JOLIVET, J. P. Journal of Colloid and Interface  Science, v. 205, p. 205–212, 1998. 3KAKIHANA, M.; YOSHIMURA, M. Bulletin of the Chemical Society of Japan, v. 72, p. 1427–1443, 1999. 

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Photocatalyst with magnetic properties applied in the degradation of pesticides.

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