Improving the Performance of PVDF/PVDF- g-PEGMA Ultrafiltration Membranes by Partial Solvent Substitution with Green Solvent Dimethyl Sulfoxide during Fabrication

Traditional organic solvents used in membranemanufacturing, such as dimethylformamide and tetrahydrofur-an, are generally very hazardous and harmful to theenvironment and human health. Their total or partialsubstitution with green solvent dimethyl sulfoxide (DMSO)is proposed to fabricate membranes composed of poly-(vinylidenefluoride) (PVDF) blended with PVDF-graft-poly(ethylene glycol) methyl ether methacrylate (PEGMA),with the purpose to accomplish a greener chemical processand enhance the membrane performance. Various organicsolvent compositions werefirst investigated using the Hansensolubility theory, and the best mixture was thus appliedexperimentally. The membrane prepared by a ratio ofN,N-dimethylacetamide/DMSO = 7:3 outperformed the membranes prepared by other solvent mixtures. This membrane showedhigh wetting behavior with the water contact angle declining from 71 to 7°in 18 s and a pure waterflux reaching values largerthan 700 L m−2h−1under 0.07 MPa applied hydraulic pressure. The membrane rejected sodium alginate at a rate of 87%, andnearly completeflux recovery was achieved following fouling and physical cleaning. The introduction of green chemistryconcepts to PVDF/PVDF-g-PEGMA blended membranes is a step forward in the goal to increase the sustainability ofmembrane production.