摘要
Highly water-selective hybrid pervaporation membranes with excellent water/ethanol separation performance and superior water channels were fabricated by incorporating graphitic carbon nitride (g-C 3 N 4 ), activated g-C 3 N 4 (O-g-C 3 N 4 ) and polydopamine modified g-C 3 N 4 (PDA@O-g-C 3 N 4 ) nanosheets into poly(vinyl alcohol) (PVA) matrix. The nonselective polymer/inorganic interface channels between PVA and g-C 3 N 4 , O-g-C 3 N 4 and PDA@O-g-C 3 N 4 in hybrid membranes were controllable constructed through hydrogen bonds, rigid and flexible chemical bonds, respectively. The membrane performances were tested in the pervaporation (PV) process for the dehydration of 90 wt% ethanol/water mixtures at 75 °C. The results revealed that with the increase of binding force among polymer/inorganic interface, from hydrogen bonds (CPVA-g-C 3 N 4 ), to rigid (CPVA-O-g-C 3 N 4 ) and flexible chemical bonds (CPVA-PDA@O-g-C 3 N 4 ), the total flux decreased from 4634 to 2328 g/(m 2 h) and the separation factor increased from 32.4 to 57.9. It is implied that the nonselective polymer/inorganic interface channels were controlled successfully. Meanwhile, compared with the pure cross-linked PVA (CPVA) membrane (total flux 2325 g/(m 2 h) and separation factor 18.7), incorporation of g-C 3 N 4 , O-g-C 3 N 4 and PDA@O-g-C 3 N 4 could all lead to an increase of surface hydrophilicity of the CPVA membranes along with an increase in membrane tortuosity and membrane water-selective channels that was favorable to the selective permeation of water molecules. Namely, these new hybrid membranes can break the “trade-off effect” effectively. Moreover, due to the ordered alignment of g-C 3 N 4 , O-g-C 3 N 4 and PDA@O-g-C 3 N 4 nanosheets and the strong interfacial interactions among these nanosheets, succinic acid (Sa) and the PVA matrix, the hybrid composite membranes showed both high swelling resistance and mechanical stability.
危险品化学品经营许可证（带存储）