Novel Poly(Aryl Ether) Membranes for Desalination by Reverse Osmosis

摘要

The synthesis and physical characteristics of sulfonated polysulfone (SPSF) filtration membranes are described. A new 1 sup H NMR method to determine the degree of sulfonation used a quaternary ammonium counterion (N(CH3)4). Characterization of the physical properties of SPSF consisted of water uptake, differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and solubility studies. Sulfonated polysulfone membranes were also characterized using scanning electron microscopy, specular reflectance infrared spectroscopy, and contact angle measurements. Studies in each of these areas were done on membranes with varying degree of sulfonation. In addition, the structure of water within the membranes was studied using proton NMR. Scanning electron microscopy proved to be a powerful tool for predicting membrane performance in desalination. Infrared, contact angle and water uptake studies provided insight into the water/membrane interaction. The use of two nonsolvents serving as a cosolvent system, to replace the traditional solvent-nonsolvent system, in the formation of asymmetric phase inversion membranes was investigated. The nonsolvent components of the cosolvent system, as well as the gelation medium, were selected based on the three-dimensional solubility parameter concept. Performance was evaluated in pressure-driven membrane separation processes.