Toxic industrial compounds (TICs) encompass a variety of chemicals used or created by industry that can pose significant danger on human health if released in the air. Such toxic industrial compounds include ammonia (NH3), nitrogen oxide (NOx), hydrogen sulfide (H2S), sulfur dioxide (SO2), arsine (AsH3), and the like. Hydrogen sulfide is one of the major environmental pollutants having its sources in natural and anthropogenic activity. Therefore, removal of TICs such as hydrogen sulfide and sulfur dioxide is important from both environmental (e.g., acid raid) and safe respiratory standpoints.
One method for removing TICs such as hydrogen sulfide and sulfur dioxide is reactive adsorption. Reactive adsorption is a form of adsorption which is enhanced through promotion of chemical reactions useful for changing an adsorbed molecule to a different one. These reactions may involve oxidation, reacting adsorbed molecules with one another or with the adsorbent surface, or with molecules present on the absorbent surface.
Various materials have been extensively investigated for use as reactive adsorbents or adsorbent supports. Examples include activated carbons, fly ash, activated carbon fibers surface, sewage sludge based adsorbents, zinc oxide, exfoliated graphite, and porous basic inorganic materials. Important factors for promoting enhanced adsorption capacity of materials are high distribution of catalytic centers promoting oxidation and ability to retain water. Other important factors include efficiency at ambient temperatures and ability to withstand the presence of moisture. Current adsorption materials are inadequate due to limited adsorption capacity especially at ambient conditions and relatively weak adsorption forces.
Accordingly, there is a need in the art to develop materials exhibiting enhanced adsorption capacity for removing significant quantities of TICs from air and strong adsorption forces at levels sufficient for preventing desorption from the surface of such materials. There is a further need for such materials capable of operating at ambient conditions.
USPTO Backgrounds
USPTO Backgrounds