Photocatalytic degradation of methyl orange and real wastewater by silver doped mesoporous TiO2 catalysts

• Synthesis of mesoporous TiO2 by hydrothermal-assistant sol–gel method.
• Investigation of the promoting effect of silver in doped mesoporous TiO2.
• Degradation of methyl orange and of a real wastewater effluent.
• Photodegradation experiments under UV and simulated solar light.
• Mesoporous TiO2 and Ag doped TiO2 are better photocatalysts than P25.

The photocatalytic activity of silver doped mesoporous TiO2 catalysts was evaluated for water treatment. Doped catalysts were prepared by impregnation-reduction with citrate using various Ag loadings (0.5 wt%, 1.5 wt% and 3 wt%) and characterized by X-Ray powder diffraction (XRD), BET and diffuse reflectance UV–vis spectroscopy (DR/UV–vis). Silver doped TiO2 catalysts retain the physical properties of mesoporous TiO2 and its hexagonal order. The degradation of methyl orange (MO) as a model organic pollutant and of a real wastewater effluent was carried out under UVC, UVB, UVA and simulated solar light irradiation. Mesoporous TiO2 showed a better activity than P25 TiO2 and photocatalytic performance of silver doped mesoporous TiO2 was enhanced compare to undoped. The mineralization of the organic pollutant was investigated by total organic carbon (TOC) measurements. The 0.5 wt%Ag/TiO2 exhibited the highest TOC abatement both for the mineralization of MO and of real wastewater under UV and simulated solar light. Moreover, the catalyst was stable and could be used repeatedly. Therefore, this catalyst is promising for photocatalytic wastewater treatment under solar irradiation, leading to a cheap technology for developing countries.

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