Fabrication of bamboo cellulose-based nanofiltration membrane for water purification by cross-linking sodium alginate and carboxymethyl cellulose and its dynamics simulation

The cross-linking coating modification strategy was adopted to construct an environmentally sustainable bamboo cellulose-based composite nanofiltration membrane (CL-NF-BCM), with bamboo cellulose providing as the support material. Solid-state Nuclear Magnetic Resonance (13C NMR) results show that alginate (ALG) and carboxymethyl cellulose (CMC) were successfully cross-linked onto the cellulose membrane. Furthermore, the transfer of chemical elements was confirmed by X-ray Photoelectron Spectroscopy (XPS) measurements. The microscopic morphology illustrates that after cross-linking coating modification, the surface of the bamboo cellulose membrane turns from a uniform porous structure to a polymerized layer with interwoven network structure. In addition, the result of Brunauer-Emmett-Teller (BET) shows that the average pore size of the as-prepared CL-NF-BCM of about 1.1 nm. The performance testing results show that the CL-NF-BCM cellulose membrane had a rejection of 48% against 500 ppm NaCl solution and membrane flux of 17 L·m−2·h−1 under a nanofiltration condition of 0.5 MPa operating pressure. This work enriches a high value-added application of bamboo products, as well as provides a novel perspective for membrane surface modification.