THE REMOVAL OF LOW CONCENTRATIONS OF IODINE FROM AIR ON A PLANT SCALE

Abstract Experiments are described in which the performance of three types of absorber for removal of iodine was assessed. The absorbers, which were each preceded by an “absolute” filter were respectively a sodium carbonate liquid scrubber, a bed of knitted copper mesh and a bed of granulated activated charcoal. The flow through each system was in the range 2000–3000 c.f.m. The iodine was released as elemental iodine vapour in a reactor shell of volume 7000 m 3 to give an initial concentration of about 1 μg 127 I and 7 μc 132 I per cubic metre of air. The results showed that the efficiency of each system decreased with time after the iodine was released and it is concluded that this was due to the partial change of the elemental iodine vapour into a form which was not so easily adsorbed. At all stages of the tests the decontamination factor of the charcoal bed was superior to that of the other two systems.