The scarcity of lithium can be effectively addressed by extracting it from salt-lake brines. In this work, aza-crown ether (diazo-18-crown-6, DA18C6) was coupled into a polyamide (PA) network interfacial polymerized by trimesoyl chloride and polyethyleneimine (PEI) for efficient Li + /Mg 2+ separation. The embedment of DA18C6 molecule into PA network was confirmed by structural characterization and density functional theory simulation, which enhanced crosslinking degree and reduced average pore size of PA selective layer. In addition, the strong interaction between DA18C6 and Li + was proven through molecular dynamics simulation. The resulting PEI@DA18C6-PA membrane displayed a high pure water permeance of 10.4 L⋅m − 2 ⋅h − 1 ⋅bar − 1 and an excellent Li + /Mg 2+ separation factor ( S Li,Mg ) of 11.2, which was comparable with most reported Li + /Mg 2+ separation membranes . Furthermore, the PEI@DA18C6-PA membrane was employed in a three-stage NF treatment process to filtrate simulated brines containing a high Mg 2+ /Li + ratio of 57. The results demonstrated that Li + can be effectively concentrated and extracted through the membrane to obtain a permeate with an ultralow Mg 2+ /Li + ratio of only 0.03, suggesting that PEI@DA18C6-PA membrane has great application potential in lithium extraction from salt-lake brines.
Aim: Anion/cation symport across cellular membranes may lead to cell apoptosis and be developed as a strategy for new anticancer drug discovery. Methodology: Four aza-crown ether–squaramide conjugates were synthesized and characterized. Their anion recognition, anion/cation symport, cytotoxicity and probable mechanism of action were investigated in details. Conclusion: These conjugates are able to form ion-pairing complexes with chloride anions and facilitate the transmembrane transport of anions via an anion/cation symport process. They can disrupt the cellular homeostasis of chloride anions and sodium cations and induce the basification of acidic organelles in live cells. These conjugates exhibit moderate cytotoxicity toward the tested cancer cells and trigger cell apoptosis by mediating the influx of chloride anions and sodium cations into live cells. Graphical abstract
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