Ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer as effective sorbent for removal of Cu²⁺ ions from water solutions (sorption of the copper ions)

ABSTRACT

The capability of the ammonium salt of the cross-linked maleic acid–allylpropionate–styrene terpolymer for the adsorption of Cu²⁺ from aqueous solutions was examined. Effect of the various experimental parameters on removal degree of the copper ions was investigated. Equilibrium data were fitted to the Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models. Kinetics studies suggested that the adsorption allowed pseudo-second-order reaction. The negative values of ΔG° and the positive value of ΔH° indicate that the sorption process is spontaneous and endothermic in nature. The positive value of ΔS° shows the increasing randomness during adsorption process. Considering the FTIR and UV–vis spectra of the sorbent after sorption, it is concluded that Cu²⁺ enters a complex with carboxylate and ester groups of the sorbent.

GRAPHICAL ABSTRACT

KEYWORDS:

• Copper ions
• cross-linking
• isotherm
• kinetics
• sorption

Acknowledgments

The authors gratefully acknowledge Dr Goncha M. Eyvazova, for help in FTIR and UV–vis spectra analysis.