Pb(ii) and Co(ii) ion removal from aqueous solutions using chitosan–Schiff base–NiFe2O4 magnetic nanocomposite adsorbent

Abstract

A one-step reaction was carried out to synthesize an NiFe₂O₄-based chitosan–Schiff base magnetic nanocomposite (CA/CSSB@NiFe) adsorbent using citric acid as a cross-linking agent, which was characterised by FTIR, TGA, XRD, BET and FE-SEM techniques. The synthesized CA/CSSB@NiFe was applied as an efficient scavenger for the adsorption of Pb(II) and Co(II) ions from water systems using batch experiments. Isotherm studies confirmed that the adsorption process fits well with the Freundlich model, suggesting multilayer adsorption. The results demonstrated that the adsorption data adhered better to a pseudo-second-order kinetic (PSO) model, confirming the chemisorption of ions with a maximum adsorption capacity of 269.77 mg g⁻¹ for Pb(II) and 253.53 mg g⁻¹ for Co(II) at room temperature. Additionally, the adsorption capacity of ions using CA/CSSB@NiFe was increased by increasing the solution temperature from 25 °C to 45 °C. The adsorption efficiency after 7 adsorption/desorption cycles exhibited a low decrease in removal percentage (<15%). Finally, the results suggested that the good scalable potential of CA/CSSB@NiFe for the uptake of Pb(II) and Co(II) ions and other metal ions from water bodies.