Role of nanohybrid NiO–Fe3O4 in enhancing the adsorptive performance of activated carbon synthesized from Yemeni-Khat leave in removal of Pb (II) and Hg (II) from aquatic systems

Abstract

Over years, existence of toxic chemical heavy metal in aquatic systems has motivated more research studies toward the preparation of effective stable solid adsorbents for the removal of toxic chemical pollutants. Therefore, in the current research study, activated carbon adsorbent (AC) was synthesized from Yemeni khat (catha edulis) leaves which are considered as waste accumulated on waste disposal areas in Yemen. KOH (2.0 N) was used as a chemical activator to produce the AC material which was subsequently heated at 400 °C. A simple co-precipitation method was used to chemically modify AC with varying weight ratios of NiO–Fe3O4 NPs (5, 15, and 25 wt %). The modified AC was used to remove toxic Pb(II) and Hg(II) ions from aquatic systems. Numerous techniques, which included x-ray diffraction (XRD), Fourier transforms infrared (FTIR), field emission scanning electron microscope (FE-SEM), and N2 adsorption/desorption isotherms, were used to confirm the morphology of AC and 5, 15, and 25 wt% NiO–Fe3O4/AC samples. The study findings demonstrated that, NiO–Fe3O4 nanoparticles improved the adsorption efficiency for toxic Pb(II) and Hg (II) ions. The AC adsorbent attained maximum removal efficiencies of 88.95% and 87.56% for Pb (II) and Hg (II) ions, respectively. In contrast, 15-NF/AC NC sample successfully attained the highest removal efficiencies of 100% for pb(II) and 99.71% for Hg(II). According to the experimental findings, the prepared NF/AC adsorbents were effective and they can be used as inexpensive and stable solid nanoadsorbents in water treatment.