CHEMICAL SEPARATIONS USING SHELL-AND-TUBE COMPOSITE POLYPHOSPHAZENE MEMBRANES

Several applications of modular shell and tube polyphosphazene coated membrane units are reported in this paper. These modules were used to measure the mixed-gas separation properties of poly[bis(phenoxy)phosph azene] based polymers on a larger scale. Transport behavior was determ ined using the variable volume technique. The test gas mixture was SO2 /N-2 at temperatures between 80 degrees C and 270 degrees C. Transport of these gases was found to be a sorption controlled process. Several organic-aqueous and organic-organic separations have been performed u sing the polyphosphazene coated shell and tube modules. The separation s include: methylene chloride/water, acetic acid/water, isopropyl alco hol/water, glycerol/water, and hexane/soy oil. The membranes were prep ared using slip casting techniques. The results of these studies show that polyphosphazene membranes can effectively be used to separate aci d gases acid organic chemicals from various waste streams in harsh, ch emically aggressive environments.