Graphene and bismuth telluride few layers entagled in nanostructured porous membranes for more sustainable water desalination

Water supply is in high demand due to the scar-city of freshwater sources and hydrogeological instability of the areas in which degradation and adverse weather conditions occur. Membrane technologies provide new greener and ecosus-tainable solutions to the wastewater treatment and water desalination management. Seawater can be regarded as a rich source of freshwater and numerous commercial elements such as minerals. Membrane Distillation (MD) and membrane crystallization (MCr) are two attrac-tive technologies, which can make saline water into freshwater and reusable minerals. The scale up of these two technologies is actually limited by the low productivity, high-energy consump-tion and recovery of polymorphic species in mixture. Herein, we demonstrate how new con-cept nanocomposite membranes boost the pro-duction of freshwater from synthetic seawater (NaCl 35 gL-1), while in specific cases there is also contrasted conductive heat loss and salt re-jection close to 100 %. Undesired fouling and thermal polarization events, which can com-promise the performance of the separation, are prevented over longer operational time. The good chemical and mechanical stability of the engineered membranes is confirmed under dif-ferent working conditions. The key issue for this kind of membranes is that few layers graphene and dichacolgenide compounds entagled in PVDF networks (Fig. 1) stimulate fast and re-versible chemisorption mechanisms, which ac-celerate water transfer through the membrane for a double effect: a) amplified production of freshwater; b) controlled formation of crystals with much more regular shape and size. As a re-sult, enhamced water desalination can be im-plemented when equipping MD/MCr devices with these edge membranes. This family of nanocomposite membranes is expected to facili-tate the fabrication of new frontier multi-functional devices counting interplay of com-plementary cooperative functions on nanoscale.