Photocatalytic and DC conductivity studies of proton exchanged KAl_0.33W_1.67O₆ and its application in Pb²⁺ removal

Abstract

The proton exchanged metal oxide of composition HAl_0.33Te_1.67O₆ (HAW) is synthesized by ion exchange method at room temperature and characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and UV-vis diffuse reflectance spectroscopy. Presence of water content in the HAW has been examined by thermogravimetric analysis. Conductivity and photocatalytic properties of HAW are compared with those of its parent KAl_0.33W_1.67O₆ (KAW). HAl_0.33W_1.67O₆ shows higher conductivity and photocatalytic activity for the degradation of methyl blue and Rhodamine B under visible light irradiation. Participation of hydroxyl radicals in the photocatalytic dye degradation has been investigated by photoluminescence studies using terephthalic acid as probe. The removal of Pb²⁺ from an aqueous solution of Pb(NO₃)₂ using pristine KAl_0.33W_1.67O₆ is also reported.