Hydrophilic 2D composite LDHs-MXene pervaporation membrane for highly efficient ethanol dehydration

Mixed matrix membranes (MMMs) demonstrate significant potential for pervaporation applications. Nevertheless, single lamella 2D materials are prone to stacking problems in membranes, resulting in unforeseen matrix inhomogeneity and defects. Here, we propose a wafer-like membrane structure designed for ethanol dehydration. This structure features a surface modification of transition metal carbides (MXenes) with layered dihydroxides (LDHs), which effectively enlarges the interlayer spacing and ameliorates the stacking issue. The LDHs-modified MXenes were then incorporated into the sodium alginate (SA) layer. The hydrophilicity, stability and morphology of the MMM were evaluated by water contact angle measurements, swelling tests and scanning electron microscopy. The experiment results indicated the hydrophilicity and stability of the MMM were effectively improved. The novel L-M@CS MMM exhibited outstanding dehydration performance for ethanol solution, with the membrane containing 0.4 wt % LDHs-modified MXenes achieving the highest permeation flux of 1377 g/(m2·h) and the optimal separation factor up to 1650. Adding hydrophilic two-dimensional LDHs-MXenes composite and CaLS into sodium alginate significantly enhanced pervaporation performance of the MMM. [Display omitted] •The introduction of LDHs effectively broadened the layer spacing between MXenes.•Composite LDHs-MXenes nanoflakes reduced the transport resistance of water molecules.•The permeation flux was increased by 80 % and the separation factor by 340 %.