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

Abstract

The spread of heavy metal in water bodies, particularly lead (Pb), has occurred as a global threat to human existence. In this study, NiO NPs was prepared by coprecipitation approach using Hagenia abyssinica 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 2+ by varying the adsorptive parameters such as pH, Bio-NiO amount, interaction time, and Pb 2+ concentration. The adsorption was 99.99% at pH 0.06 g of NiO NPs dose, 60 mg L -1 concentrations of Pb 2+ within 80 min contact time. The higher removal efficiency is could be due to higher surface area (151m 2 g -1 ). 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 2+ on the surface of Bio-NiO NPs was favorable with a maximum adsorption capacity 60.13 mgg -1 . The reusability studies confirmed that the synthesized bio-NiO NPs were an effective adsorbent for removing Pb 2+ from aqueous solution up to five cycles.