Article ID Journal Published Year Pages File Type
10377766 Journal of Colloid and Interface Science 2005 10 Pages PDF
Abstract
Carbonaceous adsorbents with controllable surface area were chemically activated with KOH at 780 °C from chars that were carbonized from corncobs at 450 °C. The pore properties, including BET surface area, pore volume, pore size distribution, and mean pore diameter of these activated carbons, were characterized by the t-plot method based on N2 adsorption isotherms. Two groups are classified according to the types of adsorption/desorption isotherms. Group I corncob-derived activated carbons, with KOH/char ratios from 0.5 to 2, exhibited BET surface area ranging from 841 to 1221 m2 / g. Group II corncob-derived activated carbons, with KOH/char rations from 3 to 6, showed high BET surface areas, from 1976 to 2595 m2 / g. From scanning electron microscopic (SEM) results, the surface morphology of honeycombed holes on corncob-derived activated carbons was significantly influenced by the KOH/char ratios. The adsorption kinetics of methylene blue, basic brown 1, acid blue 74, 2,4-dichlorophenol, 4-chlorophenol, and phenol from water at 30 °C were studied on the two groups of activated carbons, which were suitably described by two simplified kinetic models, pseudo-first-order and pseudo-second-order equations. The effective particle diffusivities of phenols and dyes at the corncob-derived activated carbons of group II are higher than those of ordinary activated carbons. The high-surface-area activated carbons were demonstrated to be promising adsorbents for pollution control and for other applications.
Related Topics
Physical Sciences and Engineering Chemical Engineering Colloid and Surface Chemistry
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