IMPROVED METHOD FOR PRODUCING CATALYTIC CARBON AND THE POTENTIAL FOR INCREASING ITS USE IN COMMERCIAL APPLICATIONS

This paper describes an improved method far producing a catalytic carb on, which was first produced in the late 1960s. The new activated carb on (AC) removes and destroys organic pollutants in aqueous solutions. To determine the effects of altering the pore structure and surface ch emistry of activated carbons, carbons differing in the amount of funct ional groups on their surfaces were prepared in three steps: (1) oxidi zing AC with boiling nitric acid, (2) washing oxidized AC with water t o remove the acid, and (3) heating oxidized AC to temperatures betewee n 100 and 925 degrees C, The surfaces of the products were characteriz ed by determining the amount of CO2 and CO evolved during temperature- programmed desorption. Depending on the desorption temperature, these modified carbons showed enhanced adsorptive and/or catalytic propertie s that included (1) carbon molecular sieves for separating oxygen from nitrogen, (2) increased capacity for adsorbing sulfur dioxide, (3) st ronger adsorption of p-nitrophenol from water, and (4) catalysis of de hydrochlorination reactions. A dehydrohalogenation catalyst produced b y the oxidation/desorption steps was found to be similar to one prepar ed in the 1960s by oxidizing AC with air at 500-700 degrees C. The deh ydrohalogenation catalyst produced by either the old method or the new method involves an oxidized surface that has been exposed to a 500-70 0 degrees C temperature range. This carbon catalyst retains modified a dsorptive properties of the AC from which it is produced, It can be us ed both to adsorb pollutants from liquid or gaseous streams and to con vert them to recyclable products.