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Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons
Group of Investigation in Solid Porous and Calorimetry, Department of Chemistry, University of the Andes, Carrera 1 No 18 A 10, Bogotá, Colombia
Department of Chemistry, Faculty of Sciences, University National of Colombia, Carrera 30 No 45-03, Bogotá, Colombia
* Author to whom correspondence should be addressed.
Received: 16 August 2011; in revised form: 4 November 2011 / Accepted: 9 November 2011 / Published: 22 December 2011
Abstract: An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g−1 for catechol aqueous solutions in a range of 20 at 1500 mg·L−1.
Keywords: activated Carbon; catechol; oxidation; reduction; adsorption; immersion enthalpies
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Moreno-Piraján, J.C.; Blanco, D.; Giraldo, L. Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons. Int. J. Mol. Sci. 2012, 13, 44-55.
Moreno-Piraján JC, Blanco D, Giraldo L. Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons. International Journal of Molecular Sciences. 2012; 13(1):44-55.
Moreno-Piraján, Juan Carlos; Blanco, Diego; Giraldo, Liliana. 2012. "Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons." Int. J. Mol. Sci. 13, no. 1: 44-55.