Membrane-Based Integrated Absorption−Oxidation Reactor for Destroying VOCs in Air

Abstract

This proof-of-concept research describes a novel membrane-based, integrated absorber−reactor operat ing at ambient temperature and atmospheric pressure. It degrades volatile organic compounds (VOCs) in a gaseous stream by ozonation in an inert stagnant fluorocarbon (FC) phase having a high ozone solubility. This FC phase acts as a reaction medium and a liquid membrane. The reactor has two sets of nonporous silicone capillaries. The VOC-containing gas flows through one set and supplies the VOC to the FC phase. The O3−O2 stream flowing through the other supplies O3 to the FC phase. There is also a set of mi- croporous Teflon tubules through which water flows removing oxidation products partitioning from the FC phase. With trichloroethylene (TCE), 60% conversion was obtained for 50 000 ppmv TCE in N2 flowing at 30 cm3/min and 40% for 18 000 ppmv flowing at 50 cm3/min. For 220 ppmv TCE feed, 90% conversion was obtained at 20 cm3/min flow rate and 60% at 60 cm3/min. A conversion in excess of 97% was achieved for a toluene feed of 205 ppmv present in N2 flowing at 11 cm3/min. No FC phase regeneration is required; it is constantly cleaned by the ozonation reactions. The materials of construction were found to hold up well under repeated experimentation.