Abstract: A dynamic adsorption device was designed for high humidity and high nitrogen oxide iodine gases produced by nuclear facilities. Silver-loaded mordenite and silver-loaded alumina were prepared for adsorbing gaseous iodine. The adsorption properties of silver-loaded mordenite and silver-loaded alumina for gaseous iodine were studied by changing the amount of silver and the concentration of iodine vapor. The experimental results show that the saturated adsorption capacity of iodine by mordenite with silver content of 15.2% is 178.4 mg/g under the conditions of 30℃, 100% relative humidity and 0.1% NO₂. The adsorption effect of silver-loaded mordenite on gaseous iodine is better than that of silver-loaded alumina. It is a complex process mainly based on chemical adsorption and physical adsorption.