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Quick high-temperature hydrothermal synthesis of mesoporous materials with 3D cubic structure for the adsorption of lysozyme

View Article: PubMed Central - PubMed

ABSTRACT

Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO106PO70EO106) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N2 adsorption, 29Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g−1 in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3.

No MeSH data available.


Adsorption of lysozyme over FDU-12-H prepared at different temperatures with an aging duration of 2 h (●) 100 °C (▼) 150 °C (▲) 180 °C and (♦) 200 °C.
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Figure 9: Adsorption of lysozyme over FDU-12-H prepared at different temperatures with an aging duration of 2 h (●) 100 °C (▼) 150 °C (▲) 180 °C and (♦) 200 °C.

Mentions: The efficiency of FDU-12 synthesized with a short aging period was tested by performing adsorption studies using lysozyme. A schematic representation of the adsorption of lysozyme over FDU-12-HX samples is shown in figure 8. A standard optimized procedure [33] with a buffer concentration of 25 mM and a solution pH of 11 was used in the adsorption experiments. Figure 9 shows the adsorption isotherms of lysozyme adsorbed onto the FDU-12-H200 samples at the solution pH of 11 wherein the amount of lysozyme adsorbed per unit weight of the mesoporous adsorbent FDU-12 with different pore diameters is plotted against the equilibrium concentration of lysozyme solution. Optimized adsorption depends on the selection of pH which in this case is at pH 11 and is near the isoelectric point of lysozyme [30, 34]. At this pH, it is believed that the coulombic repulsive forces present in the adsorbate molecules are minimized, which significantly enhances the close packing of the protein molecules [26]. Hence, there is a maximum protein adsorption seen near the isoelectric point where the hydrophobic interaction is stronger than the electrostatic interaction, due to the neutral charge between the amido groups of lysozyme, siloxane bridges of FDU-12 and intermolecular originating from the amido groups on the lysozyme surface. The adsorption near the isoelectric point also supports the close packing of the protein molecules into the mesoporous cage by decreasing the solubility of proteins and thereby enhancing good hydration of carbonate ions under optimal ionic concentration of the buffer (25 mM). Figure 9 reveals that the lysozyme adsorption increases with an initial sharp escalation from a minimum of about 3 μmol g−1 for FDU-12-H100 to a maximum of 29 μmol g−1 for FDU-12-X200.


Quick high-temperature hydrothermal synthesis of mesoporous materials with 3D cubic structure for the adsorption of lysozyme
Adsorption of lysozyme over FDU-12-H prepared at different temperatures with an aging duration of 2 h (●) 100 °C (▼) 150 °C (▲) 180 °C and (♦) 200 °C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036462&req=5

Figure 9: Adsorption of lysozyme over FDU-12-H prepared at different temperatures with an aging duration of 2 h (●) 100 °C (▼) 150 °C (▲) 180 °C and (♦) 200 °C.
Mentions: The efficiency of FDU-12 synthesized with a short aging period was tested by performing adsorption studies using lysozyme. A schematic representation of the adsorption of lysozyme over FDU-12-HX samples is shown in figure 8. A standard optimized procedure [33] with a buffer concentration of 25 mM and a solution pH of 11 was used in the adsorption experiments. Figure 9 shows the adsorption isotherms of lysozyme adsorbed onto the FDU-12-H200 samples at the solution pH of 11 wherein the amount of lysozyme adsorbed per unit weight of the mesoporous adsorbent FDU-12 with different pore diameters is plotted against the equilibrium concentration of lysozyme solution. Optimized adsorption depends on the selection of pH which in this case is at pH 11 and is near the isoelectric point of lysozyme [30, 34]. At this pH, it is believed that the coulombic repulsive forces present in the adsorbate molecules are minimized, which significantly enhances the close packing of the protein molecules [26]. Hence, there is a maximum protein adsorption seen near the isoelectric point where the hydrophobic interaction is stronger than the electrostatic interaction, due to the neutral charge between the amido groups of lysozyme, siloxane bridges of FDU-12 and intermolecular originating from the amido groups on the lysozyme surface. The adsorption near the isoelectric point also supports the close packing of the protein molecules into the mesoporous cage by decreasing the solubility of proteins and thereby enhancing good hydration of carbonate ions under optimal ionic concentration of the buffer (25 mM). Figure 9 reveals that the lysozyme adsorption increases with an initial sharp escalation from a minimum of about 3 μmol g−1 for FDU-12-H100 to a maximum of 29 μmol g−1 for FDU-12-X200.

View Article: PubMed Central - PubMed

ABSTRACT

Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO106PO70EO106) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N2 adsorption, 29Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g−1 in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3.

No MeSH data available.