(661a) Metal-Impregnated Carbon Silica Composites for NH3 and SO2 Adsorption

A biphasic material capable of effectively adsorbing a variety of light gases has promising applications in technologies such as civilian and military respiratory filters.  Such a material is advantageous over traditional single-phase materials that are limited to a niche of target gases.  Consisting of a polar siliceous phase and a non-polar carbonaceous phase, this carbon-silica composite (CSC) previously synthesized by our group targets dilute concentrations of both acid-forming gases such as SO₂ and basic gases such as NH₃ [1,2].  Through physical intermolecular attractions and varying polar contributions from each phase, the acidity/basicity of the surface of the adsorbent can capture NH₃ and SO₂ [1,2].  Pre-adsorbed water molecules under simulated humid environments enhance the adsorption of molecules such as SO₂ by forming acids that have increased reactivity [2].

In this study, to further promote light gas adsorption, a catalytic phase consisting of impregnated transition metals has been incorporated onto the surface of CSCs.  Various metal salts including Cu(NO₃), Fe₂(SO₄)₃, and ZnCl₂ have been impregnated onto CSCs through solution-condensation and wet-capillary impregnation methods.  [Metal]-CSCs have been characterized using crystallography, porosimetry, thermogravimetric analysis, and electron microscopy.  Results show that approximately 10-30 wt% of metal salt impregnant is able to increase the capacity of the non-impregnated sample by up to ~150%.

[1] T. G. Glover, K. I. Dunne, R. J. Davis, M. D. LeVan, Microporous and Mesoporous Materials, 111, 1-11 (2008).

[2] A. M. B. Furtado, Y. Wang, M. D. LeVan, Microporous and Mesoporous Materials, 165, 48-54 (2013).