Resumo

BERNAL, Valentina; GIRALDO, Liliana  e  MORENO-PIRAJAN, Juan Carlos. Acetaminophen adsorption on activated carbons at different pH. Change of enthalpy and entropy of the process. Rev.Colomb.Quim. [online]. 2018, vol.47, n.2, pp.54-62. ISSN 0120-2804.  https://doi.org/10.15446/rev.colomb.quim.v47n2.68213.

The enthalpic and entropic changes resulting from the process of acetaminophen adsorption on activated carbons with modified surface chemistry were studied. A pH variation was performed to determine the changes in the thermodynamic properties when there are charges in the adsorbate and adsorbent. It was found that the maximum adsorption capacity (1.172 mmoles g-1) corresponds to the process carried out in the activated charcoal labeled as CAR in this study at pH 7; the values of the thermodynamic functions immersion enthalpy and entropy of adsorption were -36.02 J g-1 and 0.123 J g-1 K-1, respectively. Thus, the adsorption entropy change for the acetaminophen on the activated carbons depended on the pH. It was found that this thermodynamic function varies in the following order pH 2 > pH 11 > pH 7. This behavior is related to the number of species present in the solution capable of interact with the activated carbon surface.

Palavras-chave : acetaminofén; adsorción; cambio de entropía; carbón activado; entalpía de interacción; interacciones hidrofóbicas.

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