Enhanced performances of chlorinated polyvinyl chloride (CPVC) ultrafiltration membranes by styrene-maleic anhydride copolymer

To enhance the performances of the CPVC ultrafiltration membranes, herein, styrene-maleic anhydride copolymer (SMA), an amphiphilic copolymer, was used to blend with CPVC to adjust the microstructures of membranes. The pure CPVC and SMA/CPVC composite ultrafiltration membranes were prepared by a non-solvent-induced phase inversion process. It has been proved that SMA and CPVC were partially compatible according to the rheological behavior of casting solution, DSC, FT-IR and SEM. SMA changed the phase separation mechanism and the pore structure of the composite membranes, and significantly increased the porosity. According to the results of ATR-FTIR, EDS and XPS analysis, intact anhydride groups existed on the surface of the composite membranes, which enhanced the permeability of membranes. The SMA/CPVC composite ultrafiltration membranes with 2 wt% SMA exhibited superior pure water flux (459.85 L/m2·h), protein rejection (97.2%) and permeability flux (140.69 L/m2·h) compared with the neat CPVC membrane (248.97 L/m2·h, 74.5%, 74.14 L/m2·h, respectively) at 0.1 MPa. Moreover, the flux recovery ratio increased from 55.32% to 92.68% and irreversible fouling index decreased from 42.51% to 5.00%. Importantly, the antifouling mechanism of the SMA/CPVC ultrafiltration membrane was discussed in detail.