Effects of the addition of calixarene to microphase-separated membranes for the removal of volatile organic compounds from dilute aqueous solutions

This paper describes the removal of benzene from an aqueous solution of dilute benzene using the poly(methyl methacrylate)-graft-poly(dimethylsiloxane) (PMMA-g-PDMS) membranes containing tert-butylcalix[4]arene (CA) (CA/PMMA-g-PDMS) by pervaporation. When an aqueous solution of 0.05 wt % benzene was permeated through the CA/PMMA-g-PDMS membranes, they showed strong benzene permselectivity. Both the permeability and the benzene permselectivity of the CAIPMNM-g-PDMS membranes were enhanced by increasing the CA content because the affinity of the CA/PMMA-g-PDMS membranes for benzene was increased by introducing CA into the membranes. Transmission electron microscope observations revealed that the CA/PMMA-g-PDMS membranes had a microphase-separated structure consisting of a PMMA phase and a PDMS phase containing CA. An examination of the permeation mechanism led us to the conclusion that the CA in the microphase-separated structure plays an important role as a carrier to selectively partition benzene from the aqueous solution.