A Graphene Oxide Nanofiltration Membrane Intercalated with Cellulose Nano-crystals

Graphene oxide (GO)-based nanofiltration (NF) membranes have simple fabrication and excellent performance in broad applications. However, the tight stacking of GO lamellae leads to low water flux. In this study, the interlamellar spacing of GO was increased by intercalating carboxyl-modified nano-crystalline cellulose (CCNC) to increase the membrane flux, which were prepared using vacuum filtration self-assembly. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images showed that GO and CCNC uniformly covered the holes of the substrate membrane. The maximum water flux of the CCNC-intercalated graphene oxide nanofiltration membrane was 12.74 L m−2 h−1 bar−1, which is higher than most commercial nanofiltration membranes. The membrane attained high rejection rates for organic dyes with various charges (≥ 95% for sunset yellow (SY) and ≥ 90% for methylene blue (MB) and rhodamine B (Rh B)). In contrast, the negative GO-CCNC membrane showed a moderate rejection ratio for salt ions (e.g., 80.6% for Na2SO4 and 75.5% for MgSO4). The antifouling property of the GO-CCNC nanofiltration membrane was tested using 1 g L-1 bovine serum albumin (BSA) solution. The membrane intercalated with CCNC showed better antifouling performance. The pure water flux of the membrane was recovered by more than 90% by washing.