Sol-Gel Synthesis of NiO Nanoparticles and Investigation on Adsorption Capacity in the Removal of Cr(VI) from Aqueous Solution

In this study, the NiO nanoparticles were synthesized by sol-gel method, and their physicochemical properties were investigated through XRD, SEM-EDX, TEM, and BET-BJH. The TEM results showed that average nanoparticles size was smaller than 10 nm and that there was a good agreement between the TEM and XRD results. The results indicate that NiO nanoparticles are efficient adsorbent for the removal of Cr(VI) from aqueous solutions. The effects of adsorbent, adsorbate concentration, and pH were examined. The equilibrium data could be well described by Sips model. The results of adsorption kinetics study indicated that kinetics obeyed pseudo-second order kinetic model.