ADSORPTION OF Ni(II) IONS FROM AQUEOUS SOLUTIONS ONTO MAGNETIC-POLY(DIVINYLBENZENE-CO-VINYLIMIDAZOLE) MICROBEADS: PHYSICOCHEMICAL STUDIES.

A modified suspension polymerization was used for the preparation of the mesoporous magnetic-poly(divinylbenzene-co-vinylimidazole) (m-poly(DVB-VIM)) microbeads in size 53-212 [an of average diameter. The specific surface area and the DVB/VIM mol ratio of the microspheres were determined as 29.47 m²/g and 1:4 mol/mol with Fe3O4, respectively. The physicochemical studies of adsorption of Ni(II) ions from aqueous solutions such as pH, initial concentration, amount of mesoporous m-poly(DVB-VIM) microbeads, contact time, and temperature onto the m-poly(DVB-VIM) microspheres were carried out. The maximum adsorption capacities of the m-poly(DVB-VIM) microspheres towards Ni(II) ions were determined as 13.51, 20.14, 21.00 and 23.62 mg/g at 277 K, 298 K, 318 K, and 338 K, respectively. The dynamic and equilibrium adsorption behaviours of the system were adequately described by the pseudo-second-order kinetic and the Langmuir isotherm models, respectively. Various thermodynamic parameters, such as the Gibbs' free energy change (ΔG°), the standard enthalpy change (ΔH°) and the standard entropy change (ΔS°) were also determined. Morever, after use in the adsorption, the m-poly(DVB-VIM) microbeads with paramagnetic property was separated from the via the applied magnetic force. These results indicate that the material studied could be used as a purifier for the removal of Ni(II) ions from water and wastewater under magnetic field. [ABSTRACT FROM AUTHOR]