In this work combined thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS), were used to fabricate nanofiltration membranes for water desalination at low pressures. Polyethersulfone (PES) flat-sheet membranes were successfully prepared by the combined method in which the membrane forming solution consisted of PES, N-methyl-2-pyrrolidone (NMP) as solvent and phenyl benzoate as diluent. The morphology of the formed membranes were investigated using scanning electron microscopy (SEM). Pure water permeation flux, salt (NaCl) rejection rate, pure water contact angle, and thermal gravimetric analysis (TGA) were also investigated. SEM images revealed that the membrane finger-like structure was converted to a continuous porous structure by increasing in mass ratio of phenyl benzoate to NMP. Mean pore size increased when coagulation bath temperature was increased. However, increase in the diluent to solvent ratio lead to the reduction of mean pore size. All membranes immersed in coagulation bath at 45 were more hydrophobic than other prepared samples. The highest pure water permeation flux of 766.2 Lm-2h-1 (0.2 MPa) and the highest salt rejection of 73.3% were obtained via combined thermally and non-solvent phase separation method described in this work at feed concentration of 5000 ppm.
Journal: TechConnect Briefs
Volume: 2, Materials for Energy, Efficiency and Sustainability: TechConnect Briefs 2015
Published: June 14, 2015
Pages: 271 - 274
Industry sector: Energy & Sustainability
Topics: Water Technologies