Effects of Sulfonated Polysulfone (SPSF) On Performance of Psf/Spsf Alloy Substrate and the Thin-Film-Composite NF and RO Membranes Thereof

For TFC RO or NF membranes, the polysulfone (PSF) substrate is the most widely used substrate membrane. Due to PSF’s hydrophobic properties, many researches focused on improving the hydrophilicity of PSF membrane especially in ultra filtration field. For TFC membrane, a hydrophilicity enhanced substrate may improve the binding between the PA layer and the substrate. However, hydrophilic substrates made from the addition of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) into PSF appear to produce less permeable TFC RO membranes compared to hydrophobic PSF substrates, which is due to more PA formed inside the pores. In addition, the water soluble additives may swell and get washed away from the membrane matrix during long-time operations, which will influence the membrane stability. Introducing sulfonated polymer into the membrane matrix may adjust the hydrophilicity of the substrate and maintain the membrane long-term stability.

 In this work, a series of PSF/SPSF alloy substrate membrane were prepared using phase inversion method. These substrate membranes were used for preparing NF and RO membranes. The SPSF’s influences on the flux of substrate membrane and the flux and salt rejection rate of NF or RO membranes based on the SPSF/PSF alloy substrate membranes were thoroughly investigated.