Butane sultone integrated superhydrophilic polyamide membranes for efficient ionic separation

Abstract

Organically modified polyamide (PA) selective layer, with ultrahigh perm-selectivity and good interfacial compatibility with the porous support of the ion-sieving membranes, has great importance in the advanced separation of ions. Herein, we report the synthesis of 1,4-butane sultone (BS) integrated polyamide “BS@PA” selective layer via conventional interfacial polymerization (IP). The grafted BS makes the BS@PA selective layer superhydrophilic and highly negatively charged, ultimately increases the membrane water/salt separation properties. While osmotic-driven ionic-separation, the BS@PA membrane exhibits a high water permeability of 36.9 and 79.8 mol·m−2·h−1·bar−1 with NaCl and MgCl2 salts reverse permeation rates of 6.5×10−3 and 1.8×10−3 mol·m−2·h−1·bar−1, respectively. As compared to blank PA membrane (control membrane), the BS@PA membrane demonstrates higher water permeation rates with extremely low salt/ion permeation leakage, exhibiting upper-bound water/salt, ion selectivity. The outperformed ion-separation of BS@PA membrane is ascribed to the superhydrophilic and highly negatively charged PA selective layer. This study provides a facile one-step interfacial polymerized BS integrated PA selective layer for the typical osmotically/pressure-driven ion-separation membranes to overcome conventional permeance/selectivity tradeoff of the membranes.