Adsorption of iodine by silver-impregnated hydrophobic adsorbent

Hydrophobic adsorbents, which consist of porous styrene-divinylbenzene copolymer (SDB) impregnated with silver, were developed for the removal of iodine from the dissolver off-gas (DOG). The adsorption of iodine in a simulated off-gas including iodine, NO_x and water vapor was examined by use of an adsorption column packed with the hydrophobic adsorbents. Silver impregnation methods using organic solutions were proposed. By use of dioxan and butylamine, which can swell the SDB easily, silver nitrate and metallic silver were uniformly distributed in the SDB particles. The breakthrough of iodine was not influenced by the presence of NO_x and water vapor. For a macroporous SDB with the pore volume of 1.59 ml/g-SDB and the average pore diameter of 500Å, impregnated with metallic silver at silver content of 28 wt%, a high adsorption capacity of 0.14g-I₂/cm³-adsorbent was obtained, compared to that of a commercial adsorbent. AgNO₃-impregnated silica gel. The impregnated silver was utilized about 91% for the iodine adsorption. (author)