Adsorption selectivity and dynamic adsorption behaviors of CuII, AgI, and AuIII on silica gel encapsulated by amino functionalized polystyrene.

Adsorption of precious metal ions from aqueous solutions has earned great concern recently due to environmental protection factor and the value of precious metals. In this article, a novel adsorbent silica gel microspheres encapsulated by amino functionalized polystyrene SGPSNH2 has been synthesized, and the adsorption selectivity and the dynamic adsorption properties of SGPSNH2for CuII, AgI, and AuIII has been investigated. The results displayed that SGPSNH2had excellent adsorption for AuIIIAgI in binary ion systems, especially in the systems of AuIIIZn II, AuIIINiII, and AgIZnII. The dynamic adsorption showed that the adsorption capacities of SGPSNH2for CuII, AgI, and AuIII increased with the prolonging of contact time, and the affinity order of three metal ions adsorbed by of SGPSNH2is AuIII > AgI > CuII, which is inversely correlated with their electronegativities. The regeneration capacities of SGPSNH2were investigated by using the eluent solution of 0.5 thiourea in 1 molL HCl, and it is found that the changes of the adsorption capability are relatively small after several cycles of adsorption–desorption. Thus, silica gel encapsulated by polystyrene containing amino groups SGPSNH2 is favorable and useful for the removal of precious metal ions because it is ecofriendly and easier to reuse. The comparison of SGPSNH2with other adsorbents suggests that SGPSNH2have great potential applications in environmental protection and the recovery of precious metals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]