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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.

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Degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of medium acidity.
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Fig7: Degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of medium acidity.

Mentions: Investigation of sorption properties of the synthesized composite began with determination of medium acidity for the highest removal of the studied ions. The degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of the medium acidity is presented in Figure 7. It can been seen that the highest degree of adsorption (97.25%) on the surface of the obtained composite was observed for Mo(VI) oxoanions from the solution containing 1 mg of molybdenum in the acidic medium (pH 2.5, acetic acid). At the same initial concentration of the metal in the solution, 90.6% to 90.95% of Mo(VI) oxoanions were concentrated by the chitosan-silica composite from acidic (pH 5.0, acetic acid) and neutral media. A decreasing extent of adsorption of hexavalent molybdenum was observed in the case of adsorption from the strong acetic medium formed by hydrochloric acid (pH 1.0) and from a slightly alkaline solution (pH 8.0) formed by ammonium acetate buffer corresponding to 48.12% and 11.61%, respectively. Chromium(VI) oxoanions were extracted on the surface of the obtained composite with an approximately equal degree of adsorption, but the highest adsorption was in the pH range from 2.5 to 5.0, formed by acetic acid in the case of the initial concentration of metal solution 4 μg/cm3. The lowest values of adsorption degree (25% to 37%) were found for vanadium(V) oxoanions at the initial concentration of metal solution 12 μg/cm3 (Table 2).Figure 7


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)

Degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of medium acidity.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig7: Degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of medium acidity.
Mentions: Investigation of sorption properties of the synthesized composite began with determination of medium acidity for the highest removal of the studied ions. The degree of adsorption of V(V), Mo(VI), and Cr(VI) oxoanions by composite chitosan-silica as a function of the medium acidity is presented in Figure 7. It can been seen that the highest degree of adsorption (97.25%) on the surface of the obtained composite was observed for Mo(VI) oxoanions from the solution containing 1 mg of molybdenum in the acidic medium (pH 2.5, acetic acid). At the same initial concentration of the metal in the solution, 90.6% to 90.95% of Mo(VI) oxoanions were concentrated by the chitosan-silica composite from acidic (pH 5.0, acetic acid) and neutral media. A decreasing extent of adsorption of hexavalent molybdenum was observed in the case of adsorption from the strong acetic medium formed by hydrochloric acid (pH 1.0) and from a slightly alkaline solution (pH 8.0) formed by ammonium acetate buffer corresponding to 48.12% and 11.61%, respectively. Chromium(VI) oxoanions were extracted on the surface of the obtained composite with an approximately equal degree of adsorption, but the highest adsorption was in the pH range from 2.5 to 5.0, formed by acetic acid in the case of the initial concentration of metal solution 4 μg/cm3. The lowest values of adsorption degree (25% to 37%) were found for vanadium(V) oxoanions at the initial concentration of metal solution 12 μg/cm3 (Table 2).Figure 7

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.


Related in: MedlinePlus