The gaseous adsorption and desorption characteristics of ferro-manganese crust materials and of synthetic Mn bearing substances and mesoporous zeolites

Abstract

In connection with their air pollution studies, experiments have been carried out to ascertain the room temperature adsorption of carbon monoxide, carbon dioxide, water vapor, acetaldehyde, and sulfur dioxide on marine ferro-manganese crusts, and on certain synthetically produced Mn bearing substances. Results have been compared with adsorption data on mesoporous zeolites. Limited desorption data were obtained on most of these materials. In addition, kinetics data of adsorption and desorption were also obtained on select ferro-manganese materials. The room temperature adsorption data on a select ferro-manganese material reached equilibrium-specific: adsorptivity values above 0.4 grams/gram of adsorbent at 600 torr of pressure of gas for sulfur dioxide and acetaldehyde. All of the other gases tested show much lower values. The equilibrium values at 50 torr pressure were about 0.25 for sulfur dioxide and about 0.05 for acetaldehyde. The adsorption kinetic studies conducted at room temperature on the select ferro-manganese material indicated that sulfur dioxide was adsorbed the fastest, followed by carbon dioxide, acetaldehyde, and water vapor, with sulfur dioxide reaching 99.9% adsorption in 4 minutes and water vapor in 12 minutes. Thermal desorption studies conducted on the select ferro-manganese material indicated for water four unresolved bands, going from about 50 to 230/spl deg/C, for acetaldehyde two broad but resolved bands one at about 90 and the other at about 140/spl deg/C. The significance of the findings of adsorption at low pressures indicated a more favorable situation for ferro-manganese crust materials in air pollution control of sulfur dioxide in certain vehicular emissions.