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Synthesis and adsorption properties of chitosan-silica nanocomposite prepared by sol-gel method.

Budnyak TM, Pylypchuk IV, Tertykh VA, Yanovska ES, Kolodynska D - Nanoscale Res Lett (2015)

Bottom Line: A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer.Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction.The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules.

View Article: PubMed Central - PubMed

Affiliation: Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine.

ABSTRACT
A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer. Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction. The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules. Adsorption of microquantities of V(V), Mo(VI), and Cr(VI) oxoanions from the aqueous solutions by the obtained composite has been studied in comparison with the chitosan beads, previously crosslinked with glutaraldehyde. The adsorption capacity and kinetic sorption characteristics of the composite material were estimated.

No MeSH data available.


Nitrogen adsorption/desorption isotherms of the composite chitosan-silica.
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Fig4: Nitrogen adsorption/desorption isotherms of the composite chitosan-silica.

Mentions: Figure 4 presents the nitrogen adsorption/desorption isotherms measured at 77 K for the composite chitosan-silica. The shape of the isotherm corresponds to the Langmuir isotherm, type I of the International Union of Pure and Applied Chemistry (IUPAC) classification. This type of isotherm is commonly observed in microporous materials, of which the steep increase of adsorbed quantity at low relative pressure indicates that the available microporous volume is occupied. The presence of micropores is confirmed by the diagram of pore size distribution (Figure 5), which was obtained by the adsorption branch of the isotherm using the BJH method. According to the IUPAC recommendations, the micropores are defined as pores with a diameter not exceeding 2 nm; mesopores are pores with a diameter between 2 and 50 nm, and macropores represent pores with a diameter larger than 50 nm [52]. According to the results of surface area and average pore diameter analyses, the chitosan-silica composite has the BET surface area 359 m2/g and the average pore diameter 2 nm (Figure 5). The SEM images showed that the chitosan-silica composite (Figure 6) has a rough and irregular surface.Figure 4


Synthesis and adsorption properties of chitosan-silica nanocomposite prepared by sol-gel method.

Budnyak TM, Pylypchuk IV, Tertykh VA, Yanovska ES, Kolodynska D - Nanoscale Res Lett (2015)

Nitrogen adsorption/desorption isotherms of the composite chitosan-silica.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385279&req=5

Fig4: Nitrogen adsorption/desorption isotherms of the composite chitosan-silica.
Mentions: Figure 4 presents the nitrogen adsorption/desorption isotherms measured at 77 K for the composite chitosan-silica. The shape of the isotherm corresponds to the Langmuir isotherm, type I of the International Union of Pure and Applied Chemistry (IUPAC) classification. This type of isotherm is commonly observed in microporous materials, of which the steep increase of adsorbed quantity at low relative pressure indicates that the available microporous volume is occupied. The presence of micropores is confirmed by the diagram of pore size distribution (Figure 5), which was obtained by the adsorption branch of the isotherm using the BJH method. According to the IUPAC recommendations, the micropores are defined as pores with a diameter not exceeding 2 nm; mesopores are pores with a diameter between 2 and 50 nm, and macropores represent pores with a diameter larger than 50 nm [52]. According to the results of surface area and average pore diameter analyses, the chitosan-silica composite has the BET surface area 359 m2/g and the average pore diameter 2 nm (Figure 5). The SEM images showed that the chitosan-silica composite (Figure 6) has a rough and irregular surface.Figure 4

Bottom Line: A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer.Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction.The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules.

View Article: PubMed Central - PubMed

Affiliation: Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine.

ABSTRACT
A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer. Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction. The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules. Adsorption of microquantities of V(V), Mo(VI), and Cr(VI) oxoanions from the aqueous solutions by the obtained composite has been studied in comparison with the chitosan beads, previously crosslinked with glutaraldehyde. The adsorption capacity and kinetic sorption characteristics of the composite material were estimated.

No MeSH data available.