(594a) Characterization of Pecan Shell Activated Carbon In Aqueous Chromium Systems

Venkata Daram, New Mexico State University, Las Cruces, New Mexico-88003

        Chromium (VI) belongs to the family of heavy metals and is considered a highly toxic pollutant in wastewater streams. Chromium and its compounds are widely used in leather tanning, electro-plating, anodizing baths, and rinse waters. Pecan shell, a waste product of the agricultural industry, was used for the removal of chromium (VI) from wastewater streams. Activated carbon was produced by chemical activation of pecan shells with phosphoric acid followed by oxidation with air according to the method described by Dr. Rockstraw and Dr. Syed Dastgheib. Equilibrium studies were carried out at constant pH with carbonization temperature serving as the independent study variable. Characterization studies of produced activated carbon were carried out using nitrogen adsorption isotherms, and BET surface areas were determined and found to be 555, 822, 1547, 1432 m²/g for carbons carbonized at 360, 410, 450 and 500°C respectively. The equilibrium isotherm data was fit using Langmuir and Freundlich isotherms, and with the latter providing a better fit of the chromium (VI) equilibrium adsorption data. The maximum adsorption capacity for chromium (VI) based on the Freundlich model was found to be 1.92 mmol/g Cr (VI).