Adsorption and DFT investigations of Cr(VI) removal using nanocrystals decorated with graphene oxide

Abstract

In this research, a solvothermal approach is introduced to synthesize a metal-organic frameworks (MOFs) nanocomposite (GO/UiO-66-NDC) for the removal of Cr(VI) from water. A comprehensive analysis was performed to understand the physical, chemical, and structural properties of the MOF nanocomposite. The adsorption behavior of Cr(VI) was investigated by changing various parameters, such as pH, dosage, and concentration, to determine isotherms, thermodynamics, and kinetics. The results showed that the nanocomposite had a high tolerance to pH and thermal stability, with a high adsorption capacity of 157.23 mg g−1 for Cr(VI) at pH 3 due to the presence of zirconium oxide clusters. The density functional theory simulations showed that the nanocomposite had ten times more dynamic delocalized surface states, which enhanced the adsorption capacity and agreed with the experimental results. Furthermore, the nanocomposite exhibited better regeneration performance compared to previously reported materials, making it a promising super-adsorbent for removing Cr(VI) from water.