Biopolymer based ion imprinting cryogel traps for the removal of Tl(I)

Abstract

The aim of this study is to prepare supermacroporous cryogel with embedded ion imprinted polymer (IIP) particles which can be used for the selective removal of Tl(I) from aqueous solution. In the first step, Tl(I) has complexed with chitosan and crosslinked with ephychlorohydrin. In the second step, the supermacroporous poly(hydroxyethyl methacrylate) (PHEMA) cryogel with embedded IIP particles [PHEMA/MIP composite cryogel] which have been produced by free radical polymerization initiated by N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in ice bath. The template, Tl(I), has been removed from the polymer using 0.1 M EDTA solution. The cryogel is characterized by swelling test, scanning electron microscopy, and Fourier transform infrared spectroscopy. The effective parameters on Tl(I) adsorption process have evaluated by investigating the dependency of the adsorption capacity on flow-rate, Tl(I) concentration and contact time. The maximum adsorption capacity of Tl(I) ions has been found to be 1.55 mu gg(-1). The selectivity of the IIP biopolymer cryogel has investigated by competitive adsorption of Cd(II), Cu(II), K(I), and Fe(II). The relative selectivity coefficients of IIP biopolymer cryogel are 3.98 and 62.5 for Cd(II) and Cu(II), respectively. The IIP biopolymer cryogel could be used many times without any significant decrease in the adsorption capacity. As a conclusion it can be said that the IIP biopolymer cryogel could be used for specific separation of Tl(I) ions from nuclear, industrial, and environmental waste.