No abstract

Xe is only produced by cryogenic distillation of air, and its availability is limited by the extremely low abundance. Therefore,Xerecovery after usage is the only way to guarantee sufficient supply and broad application. Herein we demonstrate DD3R zeolite as ab enchmark membrane material for CO 2 /Xe separation. The CO 2 permeance after an optimized membrane synthesis is one order magnitude higher than for conventional membranes and is less susceptible to water vapour.T he overall membrane performance is dominated by diffusivity selectivity of CO 2 over Xe in DD3R zeolite membranes,whereby rigidity of the zeolite structure playsakey role. Forr elevant anaesthetic composition (< 5% CO 2 )a nd condition (humid), CO 2 permeance and CO 2 /Xe selectivity stabilized at 2.0 10 À8 mol m À2 s À1 Pa À1 and 67, respectively,d uring long-term operation (> 320 h). This endows DD3R zeolite membranes great potential for on-stream CO 2 removal from the Xe-based closed-circuit anesthesia system. The large cost reduction of up to 4o rders of magnitude by membrane Xerecycling (> 99 + %) allows the use of the precious Xe as anaesthetics gas av iable general option in surgery.

Membranes with fast and selective ion transport have great potential for use in water-and energy-related applications. The structure and material design of the membranes play a key role in improving their performance. Conjugated microporous polymers (CMPs) as emerging membrane materials have shown uniform pore size, high surface area, and excellent chemical stability, but their mechanical properties are poor due to their brittleness. Herein, a flexible ionic CMP membrane with precisely tailored pore architecture and chemistry prepared by a coelectropolymerization (COEP) strategy is reported. The structure contains rigid monomers to maintain structural uniformity and flexible and charged monomers to enhance mechanical flexibility and improve ion selectivity by combining precise size sieving and Donnan effect. The resulting 40 nm thick CMP membranes show equivalent ion conductance compared to the commercial Nafion 117 membrane, but an order of magnitude higher ion selectivity for ion systems such as K + /Mg 2+ and Li + /Mg 2+ .

Inspired by the light-gated ion channels in cell membranes that play important roles in many biological activities, herein, we developed an artificial light-gated ion channel membrane out of conjugated microporous polymers. Through bottom-up design of the monomer molecular structure and by the electropolymerization method, the membrane pore size and thickness were precisely controlled on the molecular level. The obtained membrane exhibited uniform pore size and highly sensitive light-switchable response. The photoisomerization of the polymer chain resulted in a reversible “on and off” light control over the pore size and subsequently led to light-gated ion transport across the membrane for a series of ions including hydrogen, potassium, sodium, lithium, calcium, magnesium, and aluminum ions.