(540k) Novel Method of Fabricating Reverse Osmosis Membranes for Seawater Desalination

Seawater desalination by Reverse osmosis (RO) Technology has been in practice globally for the desalination and water treatment. The trend in Gulf countries is also shifting from thermal to membrane based RO process due to its environmental benefits. The RO process use thin film composite (TFC) membranes, which are typically made of polyamide (PA) by means of interfacial polymerization (IP) process. Although these membranes are industry standard for RO technology, but still suffer from biofouling and chlorine resistance as well as complex fabrication process. The spin assisted layer-by-layer (SA-LbL) method has been put forward to overcome certain limitations with commercial PA thin-film composite membranes. Correspondingly, some recent studies have confirmed the nanomaterial addition into the polyamide selective layer as an effective method to improve the TFC membrane efficiency. In this presentation, we discuss two different approaches for improving the membrane performance. The spin assisted layer-by-layer (SA-LbL) method for fabricating the TFC membrane by depositing the alternate ultrathin layers of diverse polyelectrolyte on commercial polysulfone ultrafiltration membrane. The membranes with 60 bilayers and 120 bilayers were fabricated by alternate deposition of strong and weak polyelectrolyte pairs. The incorporation of nanoclays into the TFC layer of the membranes at the time of IP process for developing the TFC membranes. In this study, we examined two natural nanoclays: montmorillonite and cloister in the polyamide layer of the TFC membrane. The membrane performance was studies in a cross-flow permeation-testing cell using sodium chloride solution for water flux and salt rejection. The test results confirmed substantial increase in salt rejection as well as water flux. This work confirmed that these advanced membranes are very promising, and this innovative manufacturing technique are great tool for manufacturing the RO membranes.