The collection of arsenic oxide vapor in water-filled impingers

The efficiency of water as a collection medium for arsenic oxide vapor was investigated. The vapor was generated by passing air over arsenolite (As2O3, s) at various flow rates and temperatures, passed through a particulate filter and then was collected in a series of chilled Greenburg-Smith impingers. It was found that the first impinger always collected at least 90% of the vapor while the remainder, within the limit of detection, was collected in the second impinger. No differences were found between water and 2% sodium hydroxide when used as a collection medium. Up to 15% of the collected arsenic may be absorbed on the walls of the impinger train; this amount will not dissolve in water and will be lost unless the train is thoroughly washed with hydroxide.