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Type: Artigo de periódico
Author: Vieira, AP
Santana, SAA
Bezerra, CWB
Silva, HAS
Santos, KCA
Melo, JCP
Silva, EC
Airoldi, C
Abstract: Natural lignocellulosic fiber epicarp extracted from the babassu coconut (Orbignya speciosa) was chemically modified through reaction with molten maleic anhydride without solvent, with incorporation of 189.34 mg g(-1) of carboxylic acid groups into the biopolymer structure. The success of this reaction was also confirmed by the presence of carboxylic acid bands at 1741 and 1164 cm(-1) in the infrared spectrum. Identically, the same group is observed through C-13 NMR CP/MAS in the solid state, via high field signals in the 167 pm region. Both the precursor and the immobilized maleated biopolymers presented nearly the same thermal stability and similar crystallinity to cellulose. However, the pendant carboxylic groups have the ability to remove copper with maximum sorption through a batchwise process at pH 6.0, as expected from the point of zero charge, determined to be 6.45. The sorption kinetic data were fitted to pseudo-first order, pseudo-second order, Elovich-chemisorption and intra-particle diffusion models and the equilibrium data were fitted to the Langmuir, the Freundlich and Tenkim isotherm models. Taking into account a statistical error function and determination coefficients, the data were fit to the pseudo-first and pseudo-second order kinetic and Langmuir isotherm models, with a maximum sorption capacity of copper ions of 55.09 mg g(-1). This value suggests the application of this biopolymer with incorporated carboxylate groups as a favorable agent for copper removal from appropriate systems.
Subject: Babassu
Coconut epicarp
Maleic anhydride
Country: Brasil
Editor: Brazilian Soc Chemical Eng
Citation: Brazilian Journal Of Chemical Engineering. Brazilian Soc Chemical Eng, v. 31, n. 1, n. 183, n. 193, 2014.
Rights: aberto
Date Issue: 2014
Appears in Collections:Unicamp - Artigos e Outros Documentos

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