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A highly permeable loose nanofiltration membrane prepared via layer assembled in-situ mineralization

Zhang, Jinglong, Yang, Libin, Wang, Zhan, Yang, Shigang, Li, Ping, Song, Peng, Ban, Min
Journal of membrane science 2019 v.587 pp. 117159
aqueous solutions, artificial membranes, calcium carbonate, dyeing, dyes, humic acids, hydrophilicity, mineralization, nanofiltration, nanoparticles, permeability, sodium chloride, wastewater treatment
Nanofiltration membrane with high water permeability and anti-fouling nature is particularly needed to be explored in dyeing wastewater treatment. Herein, a hydrophilic calcium carbonate/polyethyleneimine-gallic acid (CaCO3/PEI-GA) loose NF membrane was prepared via a layer assembled in-situ mineralization (LAIM) strategy. This strategy endowed the membrane with the following advantages: the formation an ultrathin CaCO3/PEI-GA selective layer with a thickness of 76 nm and the highly enhanced surface hydrophilicity due to in-situ formation of CaCO3 nanoparticles. As a result, the prepared CaCO3/PEI-GA loose NF membrane showed 154% higher water flux (48.5 L/(m2 h bar) vs. 19.1 L/(m2 h bar)) compared with the control polyethyleneimine-gallic acid (PEI-GA) loose NF membrane for 100 mg/L Congo red (CR) solution, with equivalent rejection (99.6% vs. 99.7%). Moreover, this membrane also displayed outstanding anti-fouling ability, i.e. flux recovery ratio (FRR) of 94.9% for 1000 mg/L humic acid (HA) solution, and excellent performance stability in separation of dye/salt (CR/NaCl) aqueous solution for 60 h. The aforementioned advantages of the CaCO3/PEI-GA loose NF membrane indicate its promising application in dyeing wastewater treatment.