This research works towards the development of polysulfone (PSF) membranes modified with an osmotic agent (diethylamine N-Oxide, DEAO) and tungsten (IV) disulfide (WS2) nanosheets to synthesize a self-osmotic and anti-biofouling Janus membrane. These properties significantly improve the membrane efficiency and durability. We fabricated PSF (original polymer), PSF-Cl (chloromethylated polymer), PSF-DEA (aminated polymer), and PSF-DEAO (desired polymer) membranes. These membranes were characterized using FTIR, 1H–NMR, SEM, and exposed to a forward osmosis system. FTIR results showed that there are important changes in the PSF polymer structure. We can distinguish the presence of the N–O bond in the PSF-DEAO polymer, which is part of the DEAO group. To confirm the presence of the Cl bond in the PSF-Cl polymer and the N-bonds in the PSF-DEA polymer a 1H–NMR spectrum was performed. This step is the most important, as dimethylamine is the built-in osmotic agent and helps with our osmotic pressure gradient. Scanning electron microscopy (SEM) images were taken of all PSF-DEAO membranes. The front side of the PSF-DEAO membranes exhibited significant porosity. As well as the SEM images performed to the active side shows the pores are significantly smaller. On the support side, the pores got larger when approaching the PE mesh. The cross-section view of the membrane also displays this phenomenon. Cross-section view confirms the membrane’s porosity and uniformity of the pores. To further characterize the hydrophilicity of the membranes, FO tests were used. Distilled water was used as the feed solution, and a 5% w/v sodium chloride (NaCl) solution was used as the draw solution. PSF-DEAO membrane vastly outperformed the other membranes with an average water flux of 30.38 L m−2 hr−1. This indicates that this is the most hydrophilic membrane. The PSF membrane came in second, with an average water flux of 10.61 L m−2 hr−1. This is a testament to how well the unmodified PSF membrane performs in FO membrane processes. The membrane with the lowest water flux was the PSF-Cl, with an average water flux of 5.90 L m−2 hr−1.

Development of self-osmotic and light-sensitive janus membrane for water reclamation

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.