Graphene-based membranes for membrane distillation applications: A review

Membrane distillation (MD), a growing membrane technology, has received considerable attention over the past few decades worldwide. It offers the capacity to treat high-salinity brines, including seawater as well as industrial wastewaters. MD is a thermally driven membrane process that in this process, only vapor molecules of feed obtained from vapor pressure gradient between permeate and feed sides pass through the pores of a hydrophobic membrane. Currently, large-scale use of MD has not been widespread worldwide. Therefore, the fabrication of high-quality MD membranes with high hydrophobicity, high permeability, low fouling rate, excellent mechanical strength, low thermal conductivity, and high liquid entry pressure (LEP) helps the growth of this technology worldwide. Graphene-based nanomaterials such as graphene oxide (GO) and reduced graphene oxide (rGO) have developed new opportunities for MD membranes because of their unique properties and simple synthesis procedures. In this review paper, after recognizing the fundamental concepts of the MD process and its various configurations, recent developments in the field of graphene-based MD membranes are being reviewed. In addition, after summarizing the fabrication methods, separation properties, and multiple applications of the graphene-based MD membranes, challenges, future outlooks, and potential research directions of the graphene-based MD membranes as one of the most challenging topics today are also being discussed. Bibliometric analysis is also performed.