The effect of activation method on the properties of pecan shell-activatedcarbons

Pecan shell chars were activated using steam, carbon dioxide (CO2), or phos phoric acid (H3PO4) to produce granular activated carbons (GACs). The GACs were characterized for select physical, chemical and adsorption properties. Air oxidation of the GACs was used to increase copper ion (Cu2+) adsorptio n. BET surface areas of pecan carbons were equal to or greater than commerc ial GACs. Carbon dioxide activation favored microporosity, while the other activations increased both mesoporosity and microporosity. Bulk densities a nd particle attrition of the pecan shell GACs were generally similar to the commercial carbons. Air oxidation of steam-and CO2-activated GACs increase d copper ion adsorption, although not to the same extent as GACs made by H3 PO4 activation. Copper ion adsorption and the amount of titratable function al groups greatly exceeded the values for the commercial GACs. Steam-and CO 2-activated pecan shell carbons were similar to but in some cases exceeded the ability of commercial GACs to remove certain organic compounds from wat er. GACs from pecan shells showed considerable commercial potential to remo ve metal ions and organic contaminants from water. (C) 1999 Society of Chem ical Industry.