Aminated acrylic fabric waste derived sorbent for Cd(II) ion removal from aqueous solutions: mechanism, equilibria and kinetics

An aminated acrylic fiber waste has been utilized as an adsorbent material for the removal of Cd(II) ions from aqueous solution after treatment of acrylic fiber waste with hydroxylamine hydrochloride under basic conditions, and characterized for surface chemistry, surface morphology and textural properties. The ability of this sorbent to adsorb Cd(II) ions was examined via batch adsorption methods, studying the effect of pH, sorbent and sorbate concentrations, as well as contact time. Results obtained confirm that this sorbent was effective for Cd(II) ion adsorption, with uptakes promoted by high active site density, however, the adsorption process is independent of sorbent surface area. The values obtained exceed those previously reported within the literature. Isotherm analysis using arrange of two- and three- parameter models, evaluated using non-linear regression methods with error analysis, showed that the Langmuir isotherm model most appropriately described the experimental data obtained, indicating mono layer adsorption occurs. Kinetic analysis using arrange of models in their non-linear forms provided mechanistic information, showing that pseudo -second-order behavior is involved. The synthesized aminated acrylic fiber waste derived sorbents offer significant potential for the removal of Cd(II) ions from aqueous solution through a mechanism of chelation between the electron- donating oxygen-and nitrogen-containing groups in the sorbent and the electron-accepting Cd(II) ions.