An Ion-imprinted Silica Gel Polymer Prepared by Surface Imprinting Technique Combined with Aqueous Solution Polymerization for Selective Adsorption of Ni(II) from Aqueous Solution

A novel Ni(II) ion-imprinted silica gel polymer was prepared via the surface imprinting technique combined with aqueous solution polymerization by using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as a functional monomer for the selective separation of Ni(II) from aqueous solution. The sorbent showed good chemical and thermal stability. Kinetics studies indicated that the equilibrium adsorption was achieved within 10 min and the adsorption kinetics fitted well with the pseudo-second-order kinetic model. The maximum adsorption capacity of the ion-imprinted polymer towards Ni(II) at the optimal pH of 7.0 was 66.22 mg·g⁻¹. The relative selectivity coefficients of the sorbent were 9.23, 15.71, 14.72 and 20.15 for Ni(II)/Co(II), Ni(II)/Cu(II), Ni(II)/Zn(II) and Ni(II)/Pb(II), respectively. The adsorption isotherm fitted well with Langmuir isotherm model. The thermodynamic results indicated that the adsorption of Ni(II) was a spontaneous and endothermic process. The sorbent showed good reusability evidenced by six cycles of adsorption/desorption experiments. The precision of this method is satisfactory. Thus, the prepared sorbent can be considered as a promising sorbent for selective separation of Ni(II) in real water samples.