High capacity adsorption of iodine gas by Ag.sup.0@C/SiO.sub.2 derived from rice husk: synergistic effect between C/SiO.sub.2 supports and Ag.sup.0 sites

A series of Ag.sup.0@C/SiO.sub.2 adsorbents were prepared using rice husk-based C/SiO.sub.2 as supports and applied to capture iodine gas. The results demonstrated that 50%Ag.sup.0@C/SiO.sub.2 reached a record high iodine adsorption capacity (788 ± 25 mg/g) due to the synergistic effect between C/SiO.sub.2 supports and Ag.sup.0 sites. The adsorption data of Ag.sup.0@C/SiO.sub.2 can be better fitted with the pseudo first order and Langmuir models. The iodine adsorption process included the physical and chemical adsorption. The adsorption mechanism was that Ag.sup.0 reacted with I.sub.2 to form AgI. Owing to the excellent adsorption capacity, Ag.sup.0@C/SiO.sub.2 derived from rice husk could be promising iodine gas adsorbents.