Synthesis of bulk ion-imprinted polymers (IIPs) embedded with oleic acid coated Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; for selective extraction of hexavalent uranium

Nt Tavengwa,L Chimuka,E Cukrowska

doi:10.4314/wsa.v40i4.7

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.Keywords: Bulk, magnetic imprinted polymers, oleic acid, uranium

Highlights

Heavy metals released into the environment show continuously increasing trends as a result of industrial activities and technological developments, and are a significant threat to the environment and public health due to their toxicity, accumulation in the food chain and persistence in nature (Peralta-Videa et al, 2009; Zamani et al, 2012)
This study is focused on the synthesis of magnetic ion-imprinted polymers selective to hexavalent uranium, and the application of these to aqueous samples
oleic acid (OA)-Fe3O4 was used in bulk polymerisation where 4-vinyl pyridine (4-VP) and salicylaldoxime (SALO) had a direct interaction with the uranyl ion

Summary

Introduction

Heavy metals released into the environment show continuously increasing trends as a result of industrial activities and technological developments, and are a significant threat to the environment and public health due to their toxicity, accumulation in the food chain and persistence in nature (Peralta-Videa et al, 2009; Zamani et al, 2012). This study is focused on the synthesis of magnetic ion-imprinted polymers selective to hexavalent uranium, and the application of these to aqueous samples. The extent of sorption was calculated from the amount of metal ion in solution before and after treatment with magnetic imprinted polymer.

Results

Conclusion