Hollow Fiber-Contained Liquid Membranes for Separations: An Overview

The basic technique of hollow fiber-contained liquid membrane (HFCLM) permeation-based separation of gas mixtures and liquid solutions is reviewed and existing applications in organic acid/antibiotic recovery from fermentation broths, facilitated, countertransport and co-transport of heavy metals, facilitated CO₂-N₂ (CH₄) separation, and facilitated SO₂-NO_x separation from flue gas are surveyed. New applications of the HFCLM technique include separations of organic mixtures (including isomeric) through polar liquid membranes (including cyclodextrin-containing aqueous solutions), highly selective pervaporation of organics from water, and, for gas separation, a modified technique that can treat feed at 175-200 psig. The utility of HFCLM as a reaction medium as well as the separator in separation-reaction-separation and separation-reaction processes will also be illustrated.