High flux cellulose acetate / tert-butyl cyclopolymer composite membranes for desalination: Permeability-enhancer channels by bulky and amorphous cyclopolymers

Official URL: https://dx.doi.org/10.1016/j.jece.2024.114272

This study aims to increase membrane flux while maintaining high salt rejection ability through the innovative application of tert-butyl cyclopolymer (TBCP), a bulky and amorphous cyclopolymer, as a new additive for cellulose acetate (CA) membranes. The effect of varying concentrations (2.0, 4.0, 6.0, or 8.0 wt%) and molecular weights of TBCP (33 K, 49 K, or 65 K) within the casting solutions, and the impact of varying viscosity of the membrane casting solutions on the desalination performance of the membranes were analyzed. The polymer composite membranes were characterized, and the formation of permeability-enhancing channels by the incorporation of bulky and amorphous tert-butyl cyclopolymer (TBCP) into CA matrix was confirmed. Flux and salt rejection performance of the membranes were evaluated by filtering a 2000 ppm aqueous solution of NaCl or MgSO4 salts. In the NaCl solution filtration, the flux of the modified membrane, 21 %CA+4 %TBCP 49 K, increased from 0.69 to 1.77 L/m2h, while the salt rejection changed from 96.7 % to 96.3 % compared to the control membrane. In the MgSO4 solution filtration, the modified composite membranes displayed an increment in the flux from 0.80 to 1.73 L/m2h, whereas their salt rejections remained at 100 %, as was the control membrane.