Biogenic mediated green synthesis of NiO nanoparticles for adsorptive removal of lead from aqueous solution.

The spread of heavy metal in water bodies, particularly lead (Pb), has occurred as a global threat to human existence. In this study, NiO nanoparticles (NPs) was prepared by coprecipitation approach using plant extract mediated as a reducing and template agent for the removal of Pb from aqueous solution. X-ray crystallographic diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and Brunauer-Emmett-Teller (BET) techniques were employed for the characterization of as prepared NiO NPs. The efficacy of adsorbent was evaluated on the removal of Pb by varying the adsorptive parameters such as pH, Bio-NiO amount, interaction time, and Pb concentration. The adsorption was 99.99% at pH, 0.06 g of NiO NPs dose, 60 mg L concentrations of Pb within 80 min contact time. The higher removal efficiency is could be due to higher surface area (151 mg). The adsorption process was best fitted with Freundlich isotherm and pseudo-second order kinetic models, implying that it was chemical adsorption on the heterogeneous surface. The adsorption intensity (n) was found to be 1/n < 1 (0.47) indicating adsorption of Pb on the surface of Bio-NiO NPs was favorable with a maximum adsorption capacity 60.13 mg g. The reusability studies confirmed that the synthesized bio-NiO NPs were an effective adsorbent for removing Pb from aqueous solution up to five cycles.