Opinions on the Development of Ultrahigh Permeation Membranes

Abstract

In this work, recent progresses made in the development of membranes with ultrahigh permeation rate for reverse osmosis (RO) and membrane distillation (MD) are briefly summarized and the future prospect of those membranes is discussed. In fabrication of ultrahigh permeation RO membranes, carbon nanotube, aquaporin, graphene and fluorous oligoamide nanorings were used and in all of them several orders of magnitude higher fluxes than the conventional commercial membranes were achieved. Ultrahigh MD membranes were fabricated mostly from carbonaceous materials also with several orders of magnitude higher fluxes than conventional commercial membranes, except for those made of ultrathin polymeric material, which demonstrated a high flux at a low transmembrane temperature difference. Despite these remarkable achievements, it was concluded that many challenges would be encountered to produce a sufficient amount of water by the so-called membrane chips.