Cassava Husk Powder as an Eco-Friendly Adsorbent for the Removal of Nickel (II) Ions

Here, the potential of cassava husk powder as a ecofriendly bio-sorbent of nickel (Ni) ions in aqueous media was presented. This bio-material was characterized as sorbent using several physical properties and analytical techniques which displayed a product with adequate properties as bio-sorbent toward Ni (II) ions. The sorption process was studied via six kinetic models and seven thermodynamic models. The kinetic Elovich model and the liquid film diffusion model both provided a high degree of correlation with the experimental data at 45 °C which suggests a chemisorption process. The thermodynamic studied displayed an excellent correlation with the Temkin model which suggests a uniform distribution of binding energies. From these analyses, the activation energy (Ea), the change of the standard Gibbs free energy (ΔG°), the standard enthalpy (ΔH°) and the standard entropy (ΔS°) of the sorption process were estimated using the thermodynamic equilibrium coefficients. This study revealed that Ni (II) ions adsorption process in cassava husk powder was reversible, exothermic, and with strong electrostatic interaction between metal and sorbent surface. The cassava husk powder showed an adsorption capacity of qe (25 °C) = 1.388 mg/g and qe (45 °C) = 1.265 mg/g. The bio-adsorbent is a low-cost alternative and promising green technology for efficient large-scale Ni (II) ions removal from industrial wastewater. It is an affordable technology that could also help reduce pollution in the environment.