Exploring the sandwich antibacterial membranes based on UiO-66/graphene oxide for forward osmosis performance.

Abstract Forward osmosis (FO) is an emerging membrane process driven by the osmotic pressure gradient for freshwater production. Low water flux, reverse solute diffusion, and membrane biofouling are three major issues affecting the FO performances, and the membrane material is one of the keys to solve them. The graphene oxide (GO) membrane exhibits high water flux, indicating its promising potential for application in the field of water purification. However, precisely control of the pore size of the GO membranes is necessary for efficient ion sieving. In this work, the hydrophilic metal-organic framework (UiO-66) nanoparticles, as the microporous fillers, are intercalated into the GO layers to form ultrathin "sandwich" membranes for improving the FO performances. The incorporated UiO-66 introduces uniform and suitable nanochannels that can effectively allow water to permeate through, while hinder the solutes of Na+ ions. Furthermore, the GO layers form the matrix of nanometer-thick membranes possess the antimicrobial activity (bacteriostasis of 90%), which would prevent the biofouling. In the FO model, the UiO-66/GO membrane exhibits a water flux of 29.16 LMH, which was 270% higher than the pristine GO membrane, while the reverse solute diffusion was reduced by 83.5% (12.86 gMH). Graphical abstract By the incorporation of UiO-66 into GO matrix, a sandwich membrane was obtained with highly improved FO performance compared with the pristine GO membrane. Image 1 [ABSTRACT FROM AUTHOR]