Two-dimensional material separation membranes for renewable energy purification, storage, and conversion

The current energy crisis has prompted the development of new energy sources and energy storage/conversion devices. Membranes, as the key component, not only provide enormous separation potential for energy purification but also guarantee stable and high-efficiency operation for rechargeable batteries and fuel cells. Remarkably, two-dimensional(2D) material separation membranes have attracted intense attention on their excellent performance in energy field applications, owing to high mechanical/chemical stability, low mass transport resistance, strict sizeexclusion, and abundant modifiable functional groups. In this review, we concentrate on the recent progress of 2D membrane and introduce 2D membranes based on graphene oxide(GO), MXenes, 2D MOFs, 2D COFs, and 2D zeolite nanosheets, which are applied in membrane separation(H2 collection and biofuel purification) and battery separators(vanadium flow battery, Li–S battery, and fuel cell). The mass transport mechanism, selectivity mechanism, and modification methods of these 2D membranes are stated in brief, mainly focusing on interlayer dominant membranes(GO and MXenes) and pore dominant membranes(MOFs, COFs, and zeolite nanosheets). In conclusion, we highlight the challenges and outlooks of applying 2D membranes in energy fields.

Novel Ag-AgBr decorated composite membrane for dye rejection and photodegradation under visible light

Photocatalytic membranes have received increasing attention due to their excellent separation and photodegradation of organic contaminants in wastewater.Herein,we bound Ag-AgBr nanoparticles onto a synthesized polyacrylonitrile-ethanolamine(PAN-ETA)membrane with the aid of a chitosan(CS)-TiO_(2) layer via vacuum filtration and in-situ partial reduction.The introduction of the CS-TiO_(2) layer improved surface hydrophilicity and provided attachment sites for the Ag-AgBr nanoparticles.The PAN-ETA/CS-Ti0_(2)/Ag-AgBr photocatalytic membranes showed a relatively high water permeation flux(〜47 L·m^(-2)·h^(-1)·bar^(-1))and dyes rejection(methyl orange:88.22%;congo red:95%;methyl blue:97.41%;rose bengal:99.98%).Additionally,the composite membranes exhibited potential long-term stability for dye/salt separation(dye rejection:-97%;salt rejection:-6.5%).Moreover,the methylene blue and rhodamine B solutions(20 mL,10 mg·L^(-1))were degraded approximately 90.75% and 96.81% in batch mode via the synthesized photocatalytic membranes under visible light irradiation for 30 min.This study provides a feasible method for the combination of polymeric membranes and inorganic catalytic materials.