Performance of Polyphenylsulfone-based Solvent Resistant Nanofiltration Membranes in Removing Dyes from Methanol Solution

In this study, polyphenylsulfone (PPSU) which is a third member of the polysulfone (PSF) family, with even better properties than PSF and polyethersulfone (PES) was used to prepare flat sheet solvent resistant nanofiltration (SRNF) membranes. The SRNF membranes were prepared from different PPSU concentrations (i.e. 17, 21 and 25 wt%) via phase inversion method. The performance of membranes was then evaluated by measuring the methanol flux and rejection against dyes of different molecular weight (MW) dissolved in methanol. The study revealed that the membrane with the lowest polymer concentration produced the highest pure methanol flux and required the longest time to achieve steady-state owing to its porous structure. Results also showed that the flux of the membranes tended to decrease with filtration time due to the membrane compaction. With respect to the membrane separation performance, it was found that the membrane dye rejection increased while permeate flux decreased with increasing the MW of dye components from 269 to 1470 g/mol, irrespective of the polymer concentration. Furthermore, the membrane MWCO was found to change with polymer concentration in which an increase in polymer concentration led to a lower membrane MWCO.