Synergy of adsorption and solar photoreduction for removal Cr(VI) with spinel CuFe2O4

Abstract

Abstract The synergy effect between adsorption and solar photocatalysis to remove Cr (VI) is a new approach which is environmentally friendly and sustainable development technology. the choice of photocatalyst is crucial for achieving better performance in adsorption and photocatalytic reactions. The CuFe2O4 catalysts with a spinel structure was synthesized by co-precipitation and sol-gel methods, and characterized by X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) surface area, scanning electron microscopy (SEM), Raman and Fourier transform infrared spectroscopy (FTIR). The results of this study show that the CuFe2O4-co is an excellent adsorbent and photocatalyst simultaneously for Cr (VI) removal, this activity is correlated to it structural, textural properties and a relatively narrow band gap. The catalyst is mainly crystallized in cubic inverse spinel structure, and exhibit a large pore size facilitates the accessibility of active sites by chromium ions on the surface, and which can also improve absorbed light penetration. Moreover, UV–vis diffuse reflectance spectrum (UV–vis DRS) show that the catalyst has a low band gap energy (Eg=1.2 eV), allowing a broader absorption spectrum, which enhances it capability to generate electron-hole pairs under visible light of solar irradiation.We investigated the effects of oxalic acid as a reducing agent, preparation technique, catalyst concentration, and initial dose of Cr (VI) in this research. The optimum catalyst and pollutant concentrations are 0.25g/L and 25 g/L, respectively, with a 100% reduction of Cr(VI) to Cr(III) accomplished within 1 hour.