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OwnerTerry W. Nassivera, Fitzgerald A. Sinclair +2inventors
InventorsTerry W. Nassivera, Fitzgerald A. Sinclair, Michael S. Darsillo, Ruth G. Heffes
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Novel acid-impregnated silica materials for use as environmental controls in air handling systems where highly efficient removal of ammonia and volatile amines from gaseous streams is required (e.g. clean rooms) are provided. Such silicas exhibit specific porosity and density measurements to provide a satisfactory support for an acid impregnant incorporated subsequent to initial solid silica particle production, in order to provide effective ammonia bonding sites. The combination of the silica support properties and the acid impregnant permits highly effective ammonia (or volatile amine) gas removal, resulting in excellent noxious gas removal efficiencies and capacities, particularly in comparison with prior media filtration products. Methods of using such acid-impregnated silica filter media and specific filter apparatuses are also encompassed within this invention.
A filter medium comprising acid-impregnated precipitated silica materials, wherein said materials exhibit a BET surface area of between about 20 and 700 m2/g and a water absorption of between about 50 and 500 cm3 of water per 100 g of silica;
An acid-impregnated precipitated silica filter medium that exhibits a 10% breakthrough measurement for an ammonia gas/air composition a) when present as a filter bed of 0.135 cm in height within a flask of a diameter of 4.1 cm, b) when exposed to a constant ammonia gas concentration of 50 ppm at a media velocity of 25 cm/sec at ambient temperature and pressure, and c) when exposed simultaneously to a relative humidity from 10% to 60%;
Dependencies are inferred from the claim text.