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Global Journal of Physical Chemistry. Volume 2, Issue 3 (2011) pp. 277-286
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Research Article
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Thermodynamics of cation/basic center interactions from ethylene-1,2-diamine+pentane-2,4-dione cellulose incorporated
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Edson C. da Silva Filhoa,*, , José F. de Barros Júniorb, Sirlane A. A. Santanac,
Júlio C. P. de Melod, Claudio Airoldid
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a Química, Universidade Federal do Piauí, 64800-000 Floriano, PI, Brazil
b Departamento de Química, Universidade Federal da Píaui, 64049-550, Teresina, PI, Brazil
c Departamento de Química, Universidade Federal do Maranhão, 65080-540, São Luiz, MA, Brazil
d Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP, Brazil
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Abstract |
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Chlorinated cellulose was chemically modified with
ethylene-1,2-diamine followed by pentane-2,4-dione to
yield a synthesized biopolymer that was applied for divalent cation sorption
from aqueous solution. The metals gave sorption capacities at the solid/liquid
interface of 2.32 ± 0.06, 1.85 ± 0.02, 1.70 ± 0.04 and 1.65 ± 0.02 mmol g-1 for Cu2+, Co2+,
Ni2+ and Zn2+, respectively. The isotherms were adjusted
to the Langmuir, the Freundlich and the Temkin
sorption models. The quantitative cation/base center interactions were
calorimetrically determined to give exothermic enthalpies of – (5.48 ± 0.03), –
(2.89±0.01), – (1.67±0.02) and – (3.44±0.01) kJ mol-1, negative
Gibbs energies of – (16.3±0.7), – (18.8±0.7), – (17.5±0.7) and – (18.3±0.7) kJ
mol-1, and positive entropies of 36±2, 53±2, 53±2 and 49±2 J mol-1
K-1 for the same sequence of cations. These favorable thermodynamic
data suggest that the synthesis involving cellulose produces a new useful
material for cation removal from the environment.
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Keywords |
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Cellulose; Schiff base; Pentane-2,4-dione; Sorption; Calorimetry
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