Characterization and use of high surface area activated carbons prepared from cane pith for liquid-phase adsorption

Carbonaceous adsorbents with controllable surface areas were chemically activated with KOH at 780 °C from char that had been carbonized from cane pith at 450 °C. The pore properties including the BET surface area, pore volume, pore size distribution, and mean pore diameter of these activated carbons were characterized and derived using the t-plot method based on N2 adsorption isotherms. The activated cane pith carbons, with KOH/char ratios of 2–6, exhibited BET surface areas ranging from 912 to 2299 m2 g−1. The scanning electron microscopic (SEM) observations revealed that the surface morphology of honeycombed holes on all activated cane pith carbons was significantly influenced by the KOH/char ratio. The adsorption kinetics and equilibrium isotherms of acid blue 74, methylene blue, basic brown 1, p-nitrophenol, p-chlorophenol, p-cresol, and phenol from water at 30 °C on the activated carbons were studied. The adsorption kinetics were suitably described by a simplified kinetic model, the Elovich equation. All adsorption equilibrium isotherms were in agreement with the Langmuir equation, and were used to compare the covered area (Sc/Sp) of the activated carbons at different KOH/char ratios. The high-surface-area activated carbons were proven to be promising adsorbents for pollution control and for other applications.