Air Separation by Polymer-based Membrane Technology

Separation of air to produce enriched nitrogen and oxygen has been of great significance to the chemical industry. Membrane-based gas permeation process has gained due importance over conventional methods such as cryogenic distillation, solid adsorption and solvent absorption, because it is economical, compact in size, modular in configuration and has the capacity to offer low specific power consumption. Typical applications of the membrane-produced nitrogen include blanketing, purging, inerting and underbalanced drilling, while the oxygen-enriched air is mainly used for combustion enhancement in furnaces, fuel cells, medical respiration and undersea breathing. Most membranes used in air separation are made of solid polymers. This review seeks to define the current technological factors that govern the field of application of polymeric membranes for the separation of air. Potential membrane materials, physical and chemical modifications of membranes for further research in this area are discussed.