SUPPORTED POLYMERIC LIQUID MEMBRANES FOR REMOVING ORGANICS FROM AQUEOUS-SOLUTIONS .1. TRANSPORT CHARACTERISTICS OF POLYGLYCOL LIQUID MEMBRANES

The removal or elimination of organic residues from aqueous waste stre ams represents a major need in the chemical industry. We have develope d a class of membrane called supported polymeric liquid membranes (SPL Ms) capable of removing and concentrating low molecular weight organic compounds from dilute aqueous solutions, especially those that also c ontain high levels of inorganic salts. The membranes are prepared by f illing the pores of microfiltration or ultrafiltration membranes with functional, polymeric (oligomeric) liquids having affinity for the org anic compounds of interest. Data obtained with para-nitrophenol (PNP) as the permeating organic and polyglycols as the polymeric liquid memb ranes show that the slow diffusion rates due to the viscous polymeric liquids are more than compensated for by the very high solubility resu lting from specific interactions and high density of the polymers func tional groups. This is a powerful concept that can be extended to othe r types of polymeric liquids. Quite interestingly, the transport rates of PNP through the supported polyglycol liquid membranes appear remar kably insensitive to the molecular weight and the viscosity of the pol ymeric liquids. This behavior may signal a more complex and very diffe rent transport mechanism than the usual liquid diffusion.