Development of novel membrane for seawater desalination - silver incorporated polyamide thin film nanocomposite membrane

• Main Author: Bi, Yuqi
• Other Authors: Wang Rong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Environmental engineering::Water treatment
• Online Access: https://hdl.handle.net/10356/168070
• Institution: Nanyang Technological University

Seawater desalination is a promising solution in tackling freshwater shortage given the infinite supply of seawater and reverse osmosis is one of the most commonly used techniques. It has relatively low specific energy consumption and is easy to operate. However, the trade- off effect has to be further minimised where the rate of salt rejection does not get compromised when permeability is enhanced. This ensures a more effective desalination process and lowers the operating cost. This study discusses the effects of thin film nanocomposite membranes, specifically silver nanoparticle incorporated membranes, on the reduction of trade-off effect. Silver nanoparticles of different concentrations were synthesised into the polyamide layer via in-situ interfacial polymerization. This was done by reacting sodium nitrate with sodium borohydride during interfacial polymerization to produce silver nanoparticles. The membrane samples were then tested and analysed. Results showed that silver nanoparticles impregnated membranes are effective in improving permeability and selectivity. However, performance deteriorated when the maximum loading of silver nanoparticles was exceeded. A possible reason could be the formation of nanoparticle clusters that created cracks. Variations in the concentration of silver nanoparticles also resulted in different polyamide structures and properties in terms of leaf structure, height of polyamide layer and uniformity of surface roughness. Meanwhile, little impact on hydrophobicity was observed.