Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons

International Journal of Molecular Sciences

Juan Carlos Moreno-Piraján¹  Diego Blanco² 

[1] 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; E-Mails:

关键词: activated Carbon;    catechol;    oxidation;    reduction;    adsorption;    immersion enthalpies;   

DOI  :  10.3390/ijms13010044

来源: mdpi

【 摘 要 】

An activated carbon, Carbochem^TM—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 pK_a. 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.

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.