Revista Colombiana de Química
Print version ISSN 0120-2804
BLANCO, Diego A.; GIRALDO, Liliana and MORENO, Juan Carlos. APPLICATION OF THE DUBININ-RADUSHKEVICH-KAGANER EQUATION IN THE CATECHOL, RESORCINOL AND HYDROQUINONE ADSORPTION FROM AQUEOUS SOLUTIONS ON ACTIVATED CARBON. Rev.Colomb.Quim. [online]. 2010, vol.39, n.2, pp. 237-246. ISSN 0120-2804.
The phenol, catechol, resorcinol and hydroquinone adsorption process on activated carbon from aqueous solutions is studied by means of adsorption isotherms and immersion enthalpies of the activated carbon in the phenolic compounds aqueous solutions at different concentrations. The Dubinin-Radushkevich-Kaganer model is used for calculating the maximum quantities adsorbed, XmDRK, with values between 230 and 509 mgg-1 with adsorption characteristic energies between -16,96 and -21,35 kJmol-1. The behavior that follow the results of the immersion enthalpy as a function of the concentration is similar to that of the adsorption isotherm and allows to calculate the maximum immersion enthalpy, ΔHimmax, with values between -8,89 and -15,83 kJmol-1. The enthalpic and entropic contributions to the adsorption process energy of the hydroxylated phenolic compounds in aqueous solution on activated carbon are calculated, finding that the enthalpic contribution is bigger for the phenol, catechol and hydroquinone, while for the resorcinol the entropic contribution is bigger.
Keywords : phenol; catechol; resorcinol and hydroquinone adsorption; immersion enthalpy; energy characteristic; entropic contribution.