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Type: Artigo de periódico
Title: Exploring the favorable ion-exchange ability of phthalylated cellulose biopolymer using thermodynamic data
Author: de Melo, JCP
da Silva, EC
Santana, SAA
Airoldi, C
Abstract: A phthalylated ion-exchange biopolymer was obtained by adding cellulose to molten phthalic anhydride in a quasi solvent-free procedure. Through this route 2.99 +/- 0.07 mmol g(-1) of pendant groups containing ester and carboxylic acid moieties were incorporated into the polymeric structure that was characterized by elemental analysis, solid-state carbon nuclear magnetic resonance (CP/MAS), infrared spectroscopy, X-ray diffraction, and thermogravimetry. The chemically modified polysaccharide is able to exchange cations from aqueous solution as demonstrated by batchwise methodology. The data were adjusted to a modified Langmuir equation to give 2.43 +/- 0.12 and 2.26 +/- 0.11 mmol g(-1) for divalent cobalt and nickel cations, respectively. The net thermal effects obtained from calorimetric titration measurements were also adjusted to a modified Langmuir equation, and the enthalpy of the interaction was calculated to give endothermic values of 2.11 +/- 0.28 and 2.50 +/- 0.31 kJ mol(-1) for these cations, respectively. The spontaneity of this ion-exchange process is reflected in negative Gibbs energy and with a contribution of positive entropic values. This set of thermodynamic data at the solid-liquid interface suggests a favorable ion-exchange process for this anchored biopolymer for cation exchange from the environment. (C) 2010 Published by Elsevier Ltd.
Subject: Modified cellulose
Phthalic anhydride
Country: Inglaterra
Editor: Elsevier Sci Ltd
Citation: Carbohydrate Research. Elsevier Sci Ltd, v. 345, n. 13, n. 1914, n. 1921, 2010.
Rights: fechado
Identifier DOI: 10.1016/j.carres.2010.06.012
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

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