Selective recovery of Cu(Ⅱ) through polymer inclusion membranes mediated with 2-aminomethylpyridine derivatives

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.

A preliminary study of polymer inclusion membrane for lutetium(Ⅲ)separation and membrane regeneration

This paper reports on the selective transport of Lu(Ⅲ)from La(III)and Sm(III)through a polymer inclusion membrane(PIM)composed of 40 wt%di(2-ethylhexyl)phosphinic acid(P227)and 60 wt%poly(vinylidene fluoride)(PVDF).Basically,the changes in surface morphology,thickness and water contact angle of this PVDF-based PIM containing P227(P227@PVDF PIM)with different polymer concentrations were investigated.By solvent extraction experiments,it is found that Lu(Ⅲ)can be selectively extracted from La(Ⅲ)and Sm(Ⅲ)at pH 1.5 in hydrochloric acid solution.According to this result,P227@PVDF PIM was used to selectively transport Lu(Ⅲ)from hydrochloric acid feed solution containing similar concentration of La(Ⅲ)and Sm(Ⅲ).The recovery factor of Lu(III)is 91% after 36 h,and about 5%of Sm(Ⅲ)was also transported through the PIM.The concentration of La(III)in the feed solution and the stripping solution does not change.Furthermore,to overcome the ubiquitous decline of transport efficiency caused by the loss of carrier or the damage of membrane structure after long-term use of PIMs,a process for regenerating PIMs was first proposed and implemented.By comparison of the regenerated PIM with the normal PIM,there is almost no difference in the SEM image,ATR-FTIR spectrum and Lu(III)transport efficiency.It is expected that P227@PVDF PIMs have the potential to be applied to the grouped separation of rare earth elements(REEs),and this study also can be as an inspiration for the further study on the PIMs regeneration process.

Transport and selectivity of indium through polymer inclusion membrane in hydrochloric acid medium

In the present paper, a polymer inclusion membrane （PIM） containing polyvinyl chloride （PVC）, and bis-（2-ethylhexyl） phosphate （D2EHPA） which was used as extracting agent was used for the recovery of In（Ⅲ） ions in hydrochloric acid medium. The effects of carrier concentration, feed phase pH, strip phase HCI concentration, temperature on the transport, and the membrane＇s stability and thickness were examined. And the conditions for the selective separation of In（Ⅲ） and CU（Ⅱ） were optimized. The results showed that the transport of In（Ⅲ） across PIM was consistent with the first order kinetics equation, and also it was controlled by both the diffusion of the metal complex in the membrane and the chemical reaction at the interface of the boundary layers. The transport flux （J0） was inversely proportional to the membrane thickness, however, the transport stability improved as the membrane thickness increased. The transport flux of In（Ⅲ） and CU（Ⅱ） was decreased by excessive acidity of feed phase and high concentration of Cl^- . The selectivity separation coefficient of In（Ⅲ）/Cu（Ⅱ） was up to 34.33 when the original concentration of both In（Ⅲ） and Cu（Ⅱ） was 80 mg· L^ -1 as well as the pH of the feed phase and the concentration of Cl^- in the adjusting context were 0.6 and 0.5 mol· L^-1, respectively. Within the range of pH = 1-3, the separation selectivity of In（Ⅲ）/Cu（Ⅱ） reached the peak in the case when the Cl^- concentration was 0.7 mol·L^ -1.