ZnCr-LDHs with dual adsorption and photocatalysis capability for the removal of acid Orange 7 dye in aqueous solution

Abstract The aim of this study is the exploration of the potential of Layered Double Hydroxides (LDHs) materials for the treatment of contaminated waters by organic pollutants, using a combined dual process, namely adsorption-photocatalysis. In fact, a series of LDHs of ZnCr-X where (X = Cl, SO4 and CO3) were synthesized and characterized by several techniques such as DRX, FTIR, BET, TEM, and UV-Visible spectrophotometry. The pollutant acid orange 7 (AO7) was found to be efficiently adsorbed on the surface of the three LDHs depending on the nature of the intercalated anion. The adsorption percentage of AO7 achieved for the intercalated anions SO42−, CO32− and Cl−, was 25, 32 and 49.5% respectively. ZnCr–SO4 LDH was found to be the most effective photocatalyst for AO7 dye decomposition in the UV and visible range and its photocatalytic activity was preserved during three cycles of photocatalytic tests. Such remarkable properties allow considering ZnCrSO4-LDH as a promising photocatalyst with high activity, long-term durability and excellent applicability.