Synthesis, characterization, and performance of nitrated polysulfone membranes

Wholly aromatic polysulfone was modified by nitration and was investigated as a possible membrane material for separation of inorganic solutes, low molecular weight organic solutes and dyes from aqueous solutions. The nitrated polysulfones were characterized in terms of extent of nitration, percent moisture regain, inherent iscosity, IR spectra, TGA/DTA and DSC data. Membranes were prepared from nitrate polymer and performance characteristics in terms of permeate flux and solute separation are reported. The effects of the casting solution composition and casting condition, effect of feed concentration and separation of different inorganic salts are also included. Separation data for low molecular weight polyethylene glycol (PEG) solutes and dyes are studied. Nitrated polysulfone membranes have been found to give higher separation for polyvalent anionic electrolytes. The stability of membranes in acid and alkaline medium and chlorine tolerance of the membranes are also investigated.