Abstract

RODRIGUEZ ESTUPINAN, Paola; GIRALDO, Liliana  and  MORENO, Juan Carlos. ACTIVATED CARBON SURFACE OXIDATION BY HNO₃ AND H₂O₂: EFFECT ON THE REMOVAL OF NICKEL (II) FROM AQUEOUS SOLUTION. Rev.Colomb.Quim. [online]. 2011, vol.40, n.3, pp.349-364. ISSN 0120-2804.

In this work is studied the effect in the surface chemistry modification of a granular activated carbon, CAG, by oxidation with nitric acid, CAG-N, and hydrogen peroxide, CAG-P, in the nickel ions adsorption from aqueous solution. The samples were characterized by different techniques, surface chemistry was evaluated by acidity and basicity total determinations, point of zero charge and IR spectroscopy that show the effect of oxidant agent. The textural parameters such as BET surface area and pore volumes were evaluated by gas adsorption. The BET surface area values of the solids are between 816 and 876 m²g^-1; additionally were determined immersion enthalpies in water and benzene. Finally, the experimental results of the adsorption from solution were adjusted to the Langmuir's, Freundlich's, Redlich-Peterson's and Toth's models, and were found the best adjustment for the latter. The capacity adsorption determined by Langmuir's model is between 29.68 50.97 mg g^-1, which indicates that the adsorption capacity depends to a great extent on the solid surface chemistry.

Keywords : activated carbon; surface chemistry; functional groups; enthalpy of immersion; nickel (II).