TY - JOUR
T1 - Ultra-absorbent hybrid hydrogel based on alginate and SiO2 microspheres
T2 - A high-water-content system for removal of methylene blue
AU - Panão, Caroline O.
AU - Campos, Eduardo L.S.
AU - Lima, Hugo H.C.
AU - Rinaldi, Andrelson W.
AU - Lima-Tenório, Michele K.
AU - Tenório-Neto, Ernandes T.
AU - Guilherme, Marcos R.
AU - Asefa, Tewodros
AU - Rubira, Adley F.
N1 - Funding Information:
The authors acknowledge the funding through Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) - Brazil and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – Brazil for the fellowships nos. 113881/2018-5 , 152109/2016-1 , and no. 402729/2015-3 . A.F.R. acknowledges the financial supports given by CNPq , Instituto de Ciência, Tecnologia e Inovação em Materiais Complexos Funcionais (INOMAT) and Fundação Araucária – Brazil.
PY - 2019/2/15
Y1 - 2019/2/15
N2 - This work reports the synthesis of hybrid hydrogels based on alginate and π-bonds coupled silica (SiO2) microspheres (~250 nm) with high performance for water absorption. For formation of the hybrid hydrogel, the alginate was covalently gelled in the presence of SiO2 vinylated with vinyltrimethoxysilane using crosslinking chemistry. These hydrogels can absorb until 889.76 ± (12.65) g of water per 1 g of dry polymer without their tridimensional shape being unmade. The chemical nature of the polymer and the surface charges of the microspheres play a major role in creating the highly hydrophilic structure and determining the superabsorption properties. The porosity of the matrix also contributes to increase the effectiveness of the absorption, owing to an interconnected pore network that allows absorbed water to be distributed throughout the polymer matrix. In the buffer solutions, the hydrogels showed lower capacity for absorption, which was attributed to ions from weak acids and their respective salts changing charge distribution between the polymer network and the surrounding liquid layer. The applicability of the hydrogel for removal of methylene blue (MB) was investigated. The removal of MB increases with an increase in the amount of modified alginate and monomers, but reduces with a decrease in the amount of vinylated SiO2. The experimental data were better correlated with pseudo-second order model and the Langmuir model was better fit for the equilibrium data, indicating that MB was absorbed predominantly via chemisorption owing to electrostatic interactions of the dye molecule with a single absorption site.
AB - This work reports the synthesis of hybrid hydrogels based on alginate and π-bonds coupled silica (SiO2) microspheres (~250 nm) with high performance for water absorption. For formation of the hybrid hydrogel, the alginate was covalently gelled in the presence of SiO2 vinylated with vinyltrimethoxysilane using crosslinking chemistry. These hydrogels can absorb until 889.76 ± (12.65) g of water per 1 g of dry polymer without their tridimensional shape being unmade. The chemical nature of the polymer and the surface charges of the microspheres play a major role in creating the highly hydrophilic structure and determining the superabsorption properties. The porosity of the matrix also contributes to increase the effectiveness of the absorption, owing to an interconnected pore network that allows absorbed water to be distributed throughout the polymer matrix. In the buffer solutions, the hydrogels showed lower capacity for absorption, which was attributed to ions from weak acids and their respective salts changing charge distribution between the polymer network and the surrounding liquid layer. The applicability of the hydrogel for removal of methylene blue (MB) was investigated. The removal of MB increases with an increase in the amount of modified alginate and monomers, but reduces with a decrease in the amount of vinylated SiO2. The experimental data were better correlated with pseudo-second order model and the Langmuir model was better fit for the equilibrium data, indicating that MB was absorbed predominantly via chemisorption owing to electrostatic interactions of the dye molecule with a single absorption site.
KW - Hydrogel
KW - Methylene blue
KW - Silica microspheres
KW - Sodium alginate
KW - Ultra-absorbency
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U2 - 10.1016/j.molliq.2018.11.157
DO - 10.1016/j.molliq.2018.11.157
M3 - Article
AN - SCOPUS:85057610854
VL - 276
SP - 204
EP - 213
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
SN - 0167-7322
ER -