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.

Keywords

• Silver functionalized silica aerogel
• Aging process
• Iodine adsorption
• Reaction kinetics
• Ag particles
• Reaction kinetics modeling