Photocatalytic reduction of nitrate over TiO2 and Ag-modified TiO2

Krisana Kobwittaya, Sanya Sirivithayapakorn
2014 Journal of Saudi Chemical Society  
This research work presents the efficiency of the TiO 2 and Ag-TiO 2 thin films prepared by the sol-gel method and coated onto the surface of 304 stainless steel sheets used in the photocatalytic nitrate reduction processes. The Ag-TiO 2 thin films had the weight by weight (w/w) ratio of Ag + /TiO 2 of 0.1% as Ag atom. The XRD results showed that the crystalline phase structure of TiO 2 on the Ag-TiO 2 thin films was anatase. The optical band gaps of the TiO 2 and 0.1% Ag-TiO 2 thin films were
more » ... espectively 3.27 and 2.70 eV, while the surface of the prepared catalysts was hydrophobic with the respective average water contact angles of 94.8°and 118.5°for the TiO 2 and 0.1% Ag-TiO 2 thin films. The net efficiencies of photocatalytic nitrate reduction of TiO 2 and 0.1% Ag-TiO 2 were 41.4% and 70.0%, respectively. The loading of Ag only influenced the nitrate removal efficiency without affecting the stoichiometric ratio of formate to nitrate. The net stoichiometric ratio of formate to nitrate of all experiments was 2.8:1.0, which is close to the stoichiometric ratio of 2.5:1.0 of the nitrate reduction to nitrite and then to nitrogen gas.
doi:10.1016/j.jscs.2014.02.001 fatcat:cv3xvg7b7vghjkfinpvl74o5dy