Visible light prompted and modified ZnO catalyzed rapid and efficient removal of hazardous crystal violet dye from aqueous solution: A systematic experimental study

Abstract

Zinc oxide, iron-doped zinc oxide, and nickel-doped zinc oxide were tailored by the economic co-precipitation method. The hexagonal structure of the prepared samples was affirmed by structural investigation. The optical investigation confirmed that doping of Ni and Fe metal ions tune the band gap to 2.96 eV and 2.93 eV, respectively from 2.99 eV. The porous and voids across the surface of the photocatalyst were confirmed by SEM analysis and the elemental composition was validated by EDS. The 3.5 % Fe/ZnO was found superior photocatalyst to decolorize the cationic Crystal violot (CV) dye due to its small band gap and porous surface of the catalyst. It degraded almost 99.88 % CV dye within 60 min only, which was faster than 3.5 % Ni/ZnO (95 min) and ZnO (120 min). The competitive adsorption effect by strong ionic effect shown by anions can define the role of reactive species such as hydroxyl radicals, and superoxide anions in presence of CV dye.