The effect of activation method on the properties of pecan shell-activated carbons

Abstract

Pecan shell chars were activated using steam, carbon dioxide (CO2), or phosphoric 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+) adsorption. BET surface areas of pecan carbons were equal to or greater than commercial GACs. Carbon dioxide activation favored microporosity, while the other activations increased both mesoporosity and microporosity. Bulk densities and particle attrition of the pecan shell GACs were generally similar to the commercial carbons. Air oxidation of steam-and CO2-activated GACs increased copper ion adsorption, although not to the same extent as GACs made by H3PO4 activation. Copper ion adsorption and the amount of titratable functional groups greatly exceeded the values for the commercial GACs. Steam-and CO2-activated pecan shell carbons were similar to but in some cases exceeded the ability of commercial GACs to remove certain organic compounds from water. GACs from pecan shells showed considerable commercial potential to remove metal ions and organic contaminants from water. © 1999 Society of Chemical Industry