VOC vapor permeation through a liquid membrane using triethylene glycols

Supported-liquid membranes using four kinds of triethylene glycol (TEG) liquids were used for the VOC vapor removal from air. The supported-liquid membrane was a double-layer type, in which a liquid membrane was placed on a hydrophobic microporous membrane. This construction enabled the vacuum mode permeation of the VOC vapor through the TEG liquid membranes. In the experiments using a flat type membrane cell, the VOC vapors were effectively removed from the feed air. The TEG liquid membranes showed a comparable removal performance for VOC vapors to a silicone rubber membrane. The VOC removal performance of a liquid membrane was evaluated in terms of the vapor permeability. The resulting permeability of the VOC vapor and selectivity over air depended on the hydrophobic or hydrophilic property of the liquid membrane material. The hydrophobic TEG–dibutylether liquid membrane was effective for removing hydrocarbon vapors, benzene and toluene. On the other hand, the hydrophilic TEG liquid membrane had a selectivity for water-soluble vapors, methanol, acetone and ammonia. The selectivity for a VOC vapor of a TEG liquid membrane could be explained by the solubility or absorption of the vapor.