Polysulfonamide thin-film composite reverse osmosis membranes

A series of polysulfonamide reverse osmosis membranes have been synthesized from the interfacial polycondensation reaction of aqueous 1,6-hexanediamine and 1,5-naphthalenedisulfonyl chloride (NDSC) with different amounts of the crosslinking agent 1,3,6-naphthalenetrisulfonyl chloride (NTSC). For NaCl–water feed solutions, the flux decreased and separation increased with the increased amounts of the crosslinking agent. Using the Kimura–Sourirajan transport equations, the pure water permeability coefficient, A, and solute transport coefficient, DAMK/τ, were determined; ln A versus ln DAMK/τ was linear for all membranes. Scanning electron microscopy was used to monitor the changes in surface morphology as a function of the amount of the crosslinking agent. As the amount of NTSC increased, the surface morphology become more smooth and dense.