Preparation and Characterization of Modified Polysulfone with Crosslinked Chitosan–Glutaraldehyde MWCNT Nanofiltration Membranes, and Evaluation of Their Capability for Salt Rejection

Nanofiltration membranes were successfully created using multi‐walled carbon nano‐ tubes (MWCNTs) and MWCNTs modified with amine (MWCNT‐NH2) and carboxylic groups (MWCNT‐COOH). Chitosan (CHIT) and chitosan–glutaraldehyde (CHIT‐G) were utilized as dis‐ persants. Sonication, SEM, and contact angle were used to characterize the as‐prepared membranes. The results revealed that the type of multi‐walled carbon nanotubes (MWCNT, MWCNT‐COOH and MWCNT‐NH2) used as the top layer had a significant impact on membrane characteristics. The lowest contact angle was 38.6 ± 8.5 for the chitosan‐G/MWCNT‐COOH membrane. The surface mor‐ phology of membranes changed when carbon with carboxylic or amine groups was introduced. In addition, water permeability was greater for CHIT‐G/MWCNT‐COOH and CHIT‐G/MWCNT‐NH2 membranes. The CHIT‐G/MWCNT‐COOH membrane had the highest water permeability (5.64 ± 0.27 L m−2 h−1 bar−1). The findings also revealed that for all membranes, the rejection of inorganic salts was in the order R(NaCl) > R(MgSO4).