Abstract:The Cu(II) separation behaviors with polymer inclusion membranes (PIMs) are explored by modifying 2-aminomethylpyridine derivatives with hydrophobic alkyl chains, including 2-[N-(tert-butyloxycarbonylmethyl)-2-picolyamino]acetate (AMB), N,N-dioctyl-2-aminomethylpyridine (AMD), tert-butyl 2-(N-octyl-2-picolyamino) acetate (AMC), and N,N-didecyl-2-aminomethylpyridine (AME). The transport flux and selectivity of Cu(II) are determined by optimizing composition and structure of carriers and plasticizers. The results show that the hydrophobic modification of 2-aminomethylpyridine derivatives can boost the selective transport of copper ions in PIMs and membrane stability. In the optimum composition of 30 wt.% PVC, 30 wt.% AME, and 40 wt.% NPOE, the initial flux of Cu(II) is 5.8×10^-6 mol·m^-2·s^-1. The FT-IR and XPS spectra identify that the alkyl amine functional groups of AME involve in the transport of copper chloride species. The SAXS analysis demonstrates that the generated micro-channels in PIMs induced by the hydrophobic modification of 2-aminomethylpyridine derivatives can contribute to the enhanced Cu(II) flux.

Key words: hydrophobic modification; 2-aminomethylpyridine derivative; polymer inclusion membrane; Cu(II) separation