versão On-line ISSN 1816-7950
versão impressa ISSN 0378-4738
TAVENGWA, Nikita Tawanda; CUKROWSKA, Ewa e CHIMUKA, Luke. Synthesis of bulk ion-imprinted polymers (IIPs) embedded with oleic acid coated Fe3O4 for selective extraction of hexavalent uranium. Water SA [online]. 2014, vol.40, n.4, pp.623-630. ISSN 1816-7950.
ABSTRACT A selective and reliable method for the extraction of trace quantities of U(VI) by the use of a magnetic U(VI) ion-imprinted polymer (IIP) was developed. In this study, oleic acid (OA) coated magnetite nano-particles were incorporated into the cross-linked polymeric matrix of the selective sorbent, in order to gain the physical advantages of separating the polymers. Many physico-chemical factors influence the adsorption process; uranyl ion uptake ability based on these parameters was investigated. The optimum parameters obtained were sample pH 4, 50 mg of the magnetic polymer, a contact time of 45 min and an initial U(VI) concentration of 2 mg ℓ-1. The adsorption capacities for the magnetic NIP and IIP were found to be 0.95 mg-g1 and 1.21 mg-g-1, respectively. The adsorption behaviour of U(VI) in the presence of other competing metal ions onto the cross-linked magnetic polymers was also examined in binary mixtures and the order of selectivity was found to be U(VI) > Pb(VI) > Ni(II). The resulting magnetic nano-composite polymers were found to be stable up to the sixth cycle of use and reuse. The Freundlich adsorption model was used for the mathematical description of the adsorption equilibrium and the adsorption kinetic data fitted the pseudo-first-order model with R2 > 0.92.
Palavras-chave : Bulk; magnetic imprinted polymers; oleic acid; uranium.