Characterization and phenols sorptive properties of carbons activated by sulphuric acid

In this work, sawdust was used as a source material to prepare activated carbons by chemical activation with sulphuric acid. Texture properties of these carbons were determined by measuring the adsorption of nitrogen at 77 K and of carbon dioxide at 298 K. The nitrogen adsorption isotherms were interpreted by BET equation and αs-method while carbon dioxide adsorption results were interpreted by applying the D–R equation. The nature of carbon surface functionalities was studied by FTIR spectroscopy and Boehm titration method. The adsorption of phenol, hydroquinone, resorcinol and catechol from aqueous solution at 298 K on to these carbons has been investigated. FTIR shows that the carbon surface acquires an acidic character with carboxylic groups were essentially fixed along with lactonic and phenolic groups. The equilibrium data fit well the Langmuir isotherm. The amounts of phenols adsorbed, without exception decrease with increasing the concentration of acid groups on the carbon surface. Moreover, for each carbon, the amount of phenol adsorbed follows the order phenol > hydroquinone > resorcinol > catechol.