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Degradation of Glyphosate in Soil Photocatalyzed by Fe3O4/SiO2/TiO2 under Solar Light
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
* Author to whom correspondence should be addressed.
Received: 20 February 2011; in revised form: 1 April 2011 / Accepted: 1 April 2011 / Published: 21 April 2011
Abstract: In this study, Fe3O4/SiO2/TiO2 photocatalyst was prepared via a sol-gel method, and Fe3O4 particles were used as the core of the colloid. Diffraction peaks of Fe3O4 crystals are not found by XRD characterization, indicating that Fe3O4 particles are well encapsulated by SiO2. FTIR characterization shows that diffraction peaks of Ti-O-Si chemical bonds become obvious when the Fe3O4 loading is more than 0.5%. SEM characterization indicates that agglomeration occurs in the Fe3O4/SiO2/TiO2 photocatalyst, whereas photocatalysts modified by Fe3O4/SiO2 present excellent visible light absorption performance and photocatalytic activity, especially when the Fe3O4 loading is 0.5%. Photocatalytic degradation of glyphosate in soil by these photocatalysts under solar irradiation was investigated. Results show that 0.5% Fe3O4/SiO2/TiO2 has the best photocatalytic activity. The best moisture content of soil is 30%~50%. Degradation efficiency of glyphosate reaches 89% in 2 h when the dosage of photocatalyst is 0.4 g/100 g (soil), and it increased slowly when more photocatalyst was used. Soil thickness is a very important factor for the photocatalytic rate. The thinner the soil is, the better the glyphosate degradation is. Degradation of glyphosate is not obviously affected by sunlight intensity when the intensity is below 6 mW/cm2 or above 10 mW/cm2, but it is accelerated significantly when the sunlight intensity increases from 6 mW/cm2 to 10 mW/cm2.
Keywords: photocatalytic; solar light; titanium dioxide; glyphosate
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MDPI and ACS Style
Xu, X.; Ji, F.; Fan, Z.; He, L. Degradation of Glyphosate in Soil Photocatalyzed by Fe3O4/SiO2/TiO2 under Solar Light. Int. J. Environ. Res. Public Health 2011, 8, 1258-1270.
Xu X, Ji F, Fan Z, He L. Degradation of Glyphosate in Soil Photocatalyzed by Fe3O4/SiO2/TiO2 under Solar Light. International Journal of Environmental Research and Public Health. 2011; 8(4):1258-1270.
Xu, Xuan; Ji, Fangying; Fan, Zihong; He, Li. 2011. "Degradation of Glyphosate in Soil Photocatalyzed by Fe3O4/SiO2/TiO2 under Solar Light." Int. J. Environ. Res. Public Health 8, no. 4: 1258-1270.