Sv. Ho et al., SUPPORTED POLYMERIC LIQUID MEMBRANES FOR REMOVING ORGANICS FROM AQUEOUS-SOLUTIONS .1. TRANSPORT CHARACTERISTICS OF POLYGLYCOL LIQUID MEMBRANES, Journal of membrane science, 112(1), 1996, pp. 13-27
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.