Methyl Iodide Adsorption on Reduced Silver-Functionalized Silica Aerogel: How Temperature Impacts the Adsorption?

Abstract

To understand the effect of temperature to the adsorption, 104 ppbv and 1044 ppbv methyl iodide (CHI) adsorptions on reduced silver-functionalized silica aerogel (Ag-Aerogel) at 100, 150 and 200 ℃ were performed. In the experiments, a significantly high uptake rate (3 – 4 times higher than that at 100 and 150 ℃) was observed for the 104 ppbv adsorption at 200 ℃. To explain such behavior, a potential reaction pathway was proposed and multiple physical analyses including nitrogen titration, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were performed. Based on the results, the contributing factors appear to be the formation of different Ag-I components induced by temperature, higher silver site availability, decreasing diffusion limitation, and increasing reaction rate described by the Arrhenius relationship.