| Autor: |
Capanema NSV; a Center of Nanoscience, Nanotechnology and Innovation - CeNano2I, Department of Metallurgical and Materials Engineering , Federal University of Minas Gerais , Belo Horizonte, Minas Gerais , Brazil., Mansur AAP; a Center of Nanoscience, Nanotechnology and Innovation - CeNano2I, Department of Metallurgical and Materials Engineering , Federal University of Minas Gerais , Belo Horizonte, Minas Gerais , Brazil., Mansur HS; a Center of Nanoscience, Nanotechnology and Innovation - CeNano2I, Department of Metallurgical and Materials Engineering , Federal University of Minas Gerais , Belo Horizonte, Minas Gerais , Brazil., de Jesus AC; a Center of Nanoscience, Nanotechnology and Innovation - CeNano2I, Department of Metallurgical and Materials Engineering , Federal University of Minas Gerais , Belo Horizonte, Minas Gerais , Brazil., Carvalho SM; a Center of Nanoscience, Nanotechnology and Innovation - CeNano2I, Department of Metallurgical and Materials Engineering , Federal University of Minas Gerais , Belo Horizonte, Minas Gerais , Brazil., Chagas P; b Department of Chemistry , Federal University of Minas Gerais , Belo Horizonte , Minas Gerais , Brazil., de Oliveira LC; b Department of Chemistry , Federal University of Minas Gerais , Belo Horizonte , Minas Gerais , Brazil. |
| Abstrakt: |
In this study, new eco-friendly hydrogel adsorbents were synthesized based on carboxymethylcellulose (CMC, degree of substitution [DS] = 0.7) chemically cross-linked with citric acid (CA) using a green process in aqueous solution and applied for the adsorption of methylene blue (MB). Spectroscopic analyses demonstrated the mechanism of cross-linking through the reaction of hydroxyl functional groups from CMC with CA. These CMC hydrogels showed very distinct morphological features dependent on the extension of cross-linking and their nanomechanical properties were drastically increased by approximately 300% after cross-linking with 20% CA (e.g. elastic moduli from 80 ± 15 to 270 ± 50 MPa). Moreover, they were biocompatible using an in vitro cell viability assay in contact with human osteosarcoma-derived cells (SAOS) for 24 h. These CMC-based hydrogels exhibited adsorption efficiency above 90% (24 h) and maximum removal capacity of MB from 5 to 25 mg g -1 depending on the dye concentration (from 100 to 500 mg L -1 ), which was used as the model cationic organic pollutant. The adsorption of process of MB was well-fit to the pseudo-second-order kinetics model. The desorption of MB by immersion in KCl solution (3 mol L -1 , 24 h) showed a typical recovery efficiency of over 60% with conceivable reuse of these CMC-based hydrogels. Conversely, CMC hydrogels repelled methyl orange dye used as model anionic pollutant, proving the mechanism of adsorption by the formation of charged polyelectrolyte/dye complexes. |
