Equilibrium, kinetic and mechanism studies of Cu(II) and Cd(II) ions adsorption by modified chitosan beads

• Main Authors: Sutirman, Zetty Azalea, Sanagi, Mohd. Marsin, Abd. Karim, Khairil Juhanni, Wan Ibrahim, Wan Aini, Jume, Binta Hadi
• Format: Article
• Published: Elsevier B.V. 2018
• Subjects: QD Chemistry
• Online Access: http://eprints.utm.my/id/eprint/84329/; http://dx.doi.org/10.1016/j.ijbiomac.2018.05.031
• Institution: Universiti Teknologi Malaysia

In this study, the Cu(II) and Cd(II) ions removal behavior of crosslinked chitosan beads grafted poly(methacrylamide) (abbreviated as crosslinked chitosan-g-PMAm) from single metal ion solutions was investigated. The modified chitosan beads presented a remarkable improvement in acid resistance. The batch experiments demonstrated that pH of solution played a significant role in adsorption. It was found that the adsorption of Cu(II) and Cd(II) were optimum at pH 4 and pH 5, respectively. The maximum adsorption capacities for Cu(II) and Cd(II) based on Langmuir equation were 140.9 mg g−1 and 178.6 mg g−1, respectively. Pseudo-second order gave a better fit for adsorption data with respect to linearity coefficients than pseudo-first order suggesting that chemisorption or electron transfer is the dominant mechanism of the metal ions onto crosslinked chitosan-g-PMAm. In addition, X-ray photoelectron spectroscopy (XPS) investigations revealed that adsorption of both metal ions took place on the surfaces of crosslinked chitosan-g-PMAm by chelation through C–NH2, C–O and C[dbnd]O groups. Overall, the modified chitosan has proved a promising adsorbent for removal of metal ions.