Assessment of Newly Fabricated Thin-Film Composite Nanofiltration Membranes for Seawater Treatment

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To date, reverse osmosis (RO) technology is the leading process for seawater desalination applications. However, water recovery is limited to an average of 35% because of severe fouling and scaling challenges on membrane surface. Therefore, RO requires frequent membrane cleaning and membrane replacement in a shorter period, and consequently, it will reduce the process efficiency and increases its operational costs. Therefore, a proper selection of pre-treatment process is essential to avoid the aforementioned challenges. Although conventional pre-treatment system has a considerable advantage for such an application, this system enhances limitations of corrosion and rusting in the equipment of RO system. Different systems and methods of the pre-treatment system have been developed over decades through intensive research studies and resulted in a number of promising systems, including Nanofiltration (NF) membrane technology. NF technology has several advantages, and the most importantly are the separation of the suspended particles, bacteria, viruses and divalent ions from seawater, which leading to reduce the salt concentration of the treated seawater for the desalination plants. Divalent ionic rejection will also lead to increase the water recovery ratio of the desalination plants as well as a significant reduction in operating costs. The polyamide (PA) based Thin-Film Composite (TFC) NF membranes are one of the promising and commercially available membranes for such an application. However, currently TFC-NF membranes are not well established, for example, the PA membranes are hydrophobic and prone to fouling. The less chlorine tolerance of polyamide linkages leads to degradation of membrane resulting in the loss of selectivity. Further research and development are necessary to overcome the previously mentioned issues through the development of a new generation promising membranes. This proposed study includes a new approach for the synthesis of TFC-NF membranes based molecular self-assembly concept invented at KISR. The newly developed membranes demonstrated the potential application of the TFC-NF membrane towards the seawater pretreatment application. The scope of this study will be extended to fabricate the thin film nanocomposite (TFN) membranes by incorporating different nanoparticles. The study will include laboratory investigations to assess and verify the feasibility of the newly developed membranes and compare their efficiency with the commercially available PA based TFC-NF membranes. The aim of this study is to assess the feasibility and effectiveness of the proposed membranes for treating seawater under the prevailing conditions of Kuwait. The most important deliverables of this study will include a referenced scientific and technical knowledge base on the performance and efficiency of the fabricated NF membranes compared to that in the commercially available NF membranes.