Aging Kinetics on Silver-Functionalized Silica Aerogel in Off-Gas
Streams including Dry Air, Humid Air, NO and NO2
Abstract
Aging impact on silver-functionalized silica aerogel
(Ag0-aerogel) in the off-gas streams including dry
air, humid air, 1% NO/N2, and 2%
NO2/dry air were studied. Aged
Ag0-aerogel was prepared through a continuous-flow
aging system by exposing Ag0-aerogel (unaged) to the
off-gas streams at different aging temperatures and time. Iodine loading
capacity on the aged Ag0-aerogel was obtained through
a continuous-flow adsorption system. Iodine loading capacity losses were
observed after the Ag0-aerogel was exposed to the
off-gas streams. Characterization studies were conducted to observe the
physical and chemical changes of the Ag0-aerogel after
exposed to gas streams. According to iodine adsorption data and
analyses, it was revealed that iodine loading capacity on the aged
Ag0-aerogel in the off-gas streams decreases with
increasing aging temperatures and time. The pseudo reaction model
describes experimental data well and the oxidation of
Ag0 is the rate determining step in the aging process.