Nanofiltration membranes with properly enhanced pore size and hydrophilicity by sulfobutyl ether β-cyclodextrin co-monomer for efficient antibiotic desalination

• NFMs for antibiotics/NaCl separation were prepared using SBE-β-CD as co-monomer. • The pore size and hydrophilicity were simultaneously enhanced. • The antibiotic/NaCl separation factor was enhanced to 28.6. • The flux was enhanced to 30.72 L·m −2 ·h −1 ·bar −1 . Nanofiltration (NF) membrane could be used for recovering antibiotics in the waste effluents from bacterial and fungal fermentation and other processes. By doping large hydroxyl-rich monomers with rigid structures into the selective layers of NF membrane, the selectivity between antibiotics and monovalent salts can be further improved by enhancing the pore size and hydrophilicity of the membrane, resulting in effective recovery of antibiotics. The present work fabricated NF membranes through interfacial polymerization between trimesoyl chloride (TMC) and a modified aqueous-phase piperazine solution containing the anionic cyclodextrin derivative sulfobutyl-β-cyclodextrin as a hydrophilic dopant. The addition of SBE-β-CD has the potential to enhance membrane pore size and hydrophilicity to improve the selectivity of the separated layer. The optimum membrane exhibited water flux of 30.72 L·m −2 ·h −1 ·bar −1 , rejection of 97.05 % and 84.93 % respectively to antibiotics tetracycline hydrochloride and amoxicillin and low rejection of 3.39 % to NaCl. Hence, the membrane shows high selectivity between antibiotics and monovalent salt. The membrane also has a reasonable stability during a 40 h test, which shows potential in application of antibiotic recovery.