High-flux graphene oxide nanofiltration membrane intercalated by carbon nanotubes.

A sort of novel high-flux nanofiltration membrane was fabricated by synergistic assembling of graphene and multiwalled carbon nanotubes (MWNTs), in which graphene played the role of molecular sieving and MWNTs expanded the interlayer space between neighbored graphene sheets. The MWNT-intercalated graphene nanofiltration membrane (G-CNTm) showed a water flux up to 11.3 L m(-2) h(-1) bar(-1), more than 2 times that of the neat graphene nanofiltration membrane (GNm), while keeping high dye rejection (>99% for Direct Yellow and >96% Methyl Orange). The G-CNTm also showed good rejection ratio for salt ions (i.e., 83.5% for Na2SO4, 51.4% for NaCl). We also explored the antifouling performance of G-CNTm and GNm with bovine serum albumin (BSA), sodium alginate (SA) and humic acid (HA). Both G-CNTm and GNm possessed excellent antifouling performance for SA and HA but inferior for BSA because of the strong interaction between protein and graphene sheets.