Development of Thin Film Composite Polyamide Membranes with Polydopamine/Molecular Sieve Layers for Water Desalination through Reverse Osmosis

We developed a method to increase membrane performance and particle stability of molecular sieves in traditional polyamide thin film nanocomposite (TFN) membranes. Compared to common particle addition into polyamide casting solution, we stabilized particles by thin bio-inspired adhesion polydopamine layer, on microporous polysulfone support, and then we interfacially synthesized polyamide on top of this layer. In this work, we present our results for development of thin film composite (TFC) polyamide membranes on polydopamine layer with molecular sieves particles on polysulfone support membrane. First, we synthesized dopamine layer with different particle content and different particle size. Then, we synthesized a series of polyamide membranes via interfacial polymerization. For comparison, we also synthesized regular TFC and TFN polyamide membranes. Then we measured the permeability and selectivity performance using dead-end filtration and cross-flow testing system. We report the synthesized membrane surface and morphology result with contact angle, Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy.