Catalytic Trapping of Methylradioiodide by Beds of Impregnated Charcoal

The trapping or retention efficiency of impregnated charcoal beds for the vapor of methylradioiodide tagged with ¹³¹I was determined under various flow conditions by radioactive counting of each of eight equal-volume segments of the bed, including that of the large backup section. The trapping was catalytic in nature and obeyed first-order kinetics. Over a ten-fold change in residence time, the rate constant increased nonlinearly with increase in superficial linear velocity in accordance with theory.