Amino-functionalized glycidyl methacrylate based macroporous copolymers as metal ion sorbents

Abstract

Four samples of macroporous crossliaked poly(glycidyl methacry late-co-ethy lene glycol dimethacrylate), poly(GMA-co-EGDMA), were synthesized by suspension copolymerization and functionalized by ring-opening reaction of the pendant epoxy groups wich etylone dramine and diethylene tiamine. Initial poly(GMA-co-EGDMA), as well as amino-functionalized samples poly(GMA-co-EGDMA)-en and poly(GMA-co-EGDMA)-deta, were characterized by FT-IR spectroscopy and elemental analysis. The sorption of Cu(lI) ions under static conditions on amino-functionalized samples was very rapid, with t1/2 value (time required to reach 50%6 of the total sorption capacity) beyond 1 min. The uptake of Ag(I) and Ni(II) ions on poly(GMA-co-EGDMA)-deta was also rather fast, with Lug of'1 and 2 minutes, respectively. Macroporous crosslinked poly (GMA-co-EGDMA)-deta showed considerably lower affinity for Co(II) ions, with t1/2 value of 13.8 min. The maximum sorption capacities of poly (GMA-co-EGDMA)-deta under non-competitive conditions at pH 5 were 2.41 mmol/g for Cu(II), 1.88 mmol/g for Co(II). 1.81 mmol/g for Ni(II) and 0.80 mmol/g for Cd(II) ions. The selectivity of poly(GMA-co-EGDMA)-deta towards Cu(II), Co(II), Cd(II) and Ni(II) investigated under competitive conditions was pH dependent. While at pH = I poly(GMA-co-EGDMA)-deta showed somewhat higher uptake for Cd(II) over other ions, at pH 5 the selectivity for Cu(II) over Ni(II) and Co(II) was 4 : 1, and over Cd(II) was 1.6 : 1. The uptakes of N(II) and Co(II) ions stayed almost the same in the whole pH range, i.e. around 0.20 mmol/g. The two parameters mass transter Thomas model was found to be suitable for describing data obtained from the column experiments carried out with single-component Cu(ll) solution and multi-component Cu(II), NI(II), Co(II) and Cd(II) solution. The possibility ol metal recovery and repeated use of the chelating copolymer was tested in several sorption/desorption cycles. Regeneration experiments performed with 0,1 and 1 M H2SO4, showed Cu(II) capacity loss of 50 % in first sorption/desorption cycle. The sorption capacity increased when additional neutralization with 0.1 and I M NaOH was performed after each sorption/desorption cycle.