Solid Phase Extraction of Trace Cobalt(II) from Aqueous Solutions through Physicochemical Adsorption by Surface Ion-Imprinted Polymer

Abstract

A novel surface ion-imprinted polymer (S-IIP) has been synthesized by surface ion-imprinting concept in the presence of sodium trititanate whisker, Sr(II), chitosan and γ-Glycidoxypropyl trimethoxysilane (KH-560) for selective solid-phase extraction (SPE) of trace Co(II) from aqueous solutions. Characterizations of S-IIP were achieved by FT-IR spectra, SEM and surface area measurement. Results showed that the adsorption of cobalt(II) onto S-IIP follows pseudo-second order kinetics and could be fitted by the Langmuir isotherm with the maximum adsorption capacity Q being 8.27 mg×g-1 at 25°C. Thermodynamic parameters including DHº, DGº andDSº were calculated and it is indicated that Co(II) adsorption on S-IIP is exothermic, spontaneous and physical adsorption reaction. Moreover, according to the dimensionless separation factor RL (RL<1) it indicates that it’s a highly favourable adsorption. Finally, the detection limit (3s) of 5.6 ng·mL-1with the relative standard deviation (RSD) for 1.0 μg×mL-1 cobalt(II) of 1.86% (n=10) were obtained.