Purification of air mixed with solvent vapor by wet scrubbing and degradation of the solvent by ultraviolet light irradiation of the spent scrubbing liquid, and particularly in a recycle process for use in dry-cleaning machines

摘要

Solvent loaded air from the drum of a cleaning machine is absorbed in a liquid which is, either simultaneously or subsequently, irradiated with UV light. The scrubbed air may be returned to the cleaning machine drum to entrain further solvent , and the process repeated until the solvent concentration in the air coming from the drum is at an acceptable level , e.g. not greater than 2 g/m<3> for perchloroethylene; the regenerated scrubbing liquor is recirculated. In order to speed up the degradation process, oxidizing agents, such as oxygen, ozone, and hydrogen peroxide, and/or catalysts such as iron and titanium dioxide may be added to the scrubbing liquor.