Abstract
Chromium (VI) compounds are harmful when ingested, and even low concentrations of these compounds are lethal. Chromium is a carcinogenic chemical that is widely used in tanning industry. The effluents from this process require efficient treatments, and activated carbon (AC) can be useful to treat the waste waters where the chromium concentration is low. This work presents the basic characterization and Cr (VI) adsorption capacity of three different shapes of an AC obtained from oil palm endocarp, produced by a company located in Colombia, South America. Moisture, apparent density, ashes, pH, and methylene blue index were measured for pellets, granular and powder shapes of AC. Kinetics of adsorption were evaluated for the three shapes of AC for a time of 2 hours, pH less than 2, and room temperature. It was found that for pelletized and powder AC, the adsorption of Cr (VI) follows pseudo-second order kinetics, while in granular AC the adsorption of Cr (VI) is predominantly of intra-particle diffusion type. Results from adsorption kinetics also suggest that the three shapes of AC can be used to remove heavy metals such as Cr (VI) from waste waters, in order to meet the country environmental standards. The results show that in general, the granular AC performs the best among the three shapes, and an optimization procedure is required to lower moisture and ash contents, especially for the pellets and powder AC, so these carbons can provide a suitable alternative for environmental applications.
