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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.


29Si MAS NMR spectra of (A) FDU-12-H prepared at different temperatures with an aging duration of 2 h (a) 100 °C (b) 130 °C (c) 150 °C (d) 180 °C, and (e) 200 °C, and (B) deconvoluted 29Si MAS NMR spectra of FDU-12-H200.
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Figure 4: 29Si MAS NMR spectra of (A) FDU-12-H prepared at different temperatures with an aging duration of 2 h (a) 100 °C (b) 130 °C (c) 150 °C (d) 180 °C, and (e) 200 °C, and (B) deconvoluted 29Si MAS NMR spectra of FDU-12-H200.

Mentions: In order to further understand the silanol group condensation at different synthesis temperatures and the quick formation of mesostructures at high synthesis temperature, the samples were analyzed by the solid state 29Si MAS NMR and the data are given in figure 4(A). The spectra were deconvoluted into three well-resolved peaks of chemical shifts around −93, −103 and −112 ppm which corresponds to Q2, Q3, Q4, respectively (figure 4(B)). Q2(Si(OSi)2(OH)2) denotes Si bound to two Si–O moieties and two OH groups whereas Q3(Si(OSi)3(OH)) represents Si bound to three Si–O moieties and one OH group. On the other hand, Q4(Si(OSi)4) denotes Si species bound tetragonally to four other Si–O groups [31]. The percentage areas of different Si bonding in the wall structure of the samples prepared at different temperatures are given in table 3. As can be noted in table 3, when the synthesis temperature is increased, the percentage area of the Q4 increases with the concomitant decrease of Q3 and Q2. This confirms the enhancement of the condensation of silanol groups to Si–O–Si when the synthesis temperature of FDU-12 is high. It should also be noted that the decrease in silanol groups in the samples prepared at high temperature offers a high hydrophobic surface which is good for the adsorption of biomolecules [31]. In addition, a high degree of silanol condensation in the wall structure within a short duration of time at high temperature particularly favours other application possibilities for FDU-12 with cage-type pores because these highly cross-linked siloxane moieties offer high hydrothermal stability due to strong Si–O–Si bonding but a lower number of Si–OH groups in the walls.


Quick high-temperature hydrothermal synthesis of mesoporous materials with 3D cubic structure for the adsorption of lysozyme
29Si MAS NMR spectra of (A) FDU-12-H prepared at different temperatures with an aging duration of 2 h (a) 100 °C (b) 130 °C (c) 150 °C (d) 180 °C, and (e) 200 °C, and (B) deconvoluted 29Si MAS NMR spectra of FDU-12-H200.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: 29Si MAS NMR spectra of (A) FDU-12-H prepared at different temperatures with an aging duration of 2 h (a) 100 °C (b) 130 °C (c) 150 °C (d) 180 °C, and (e) 200 °C, and (B) deconvoluted 29Si MAS NMR spectra of FDU-12-H200.
Mentions: In order to further understand the silanol group condensation at different synthesis temperatures and the quick formation of mesostructures at high synthesis temperature, the samples were analyzed by the solid state 29Si MAS NMR and the data are given in figure 4(A). The spectra were deconvoluted into three well-resolved peaks of chemical shifts around −93, −103 and −112 ppm which corresponds to Q2, Q3, Q4, respectively (figure 4(B)). Q2(Si(OSi)2(OH)2) denotes Si bound to two Si–O moieties and two OH groups whereas Q3(Si(OSi)3(OH)) represents Si bound to three Si–O moieties and one OH group. On the other hand, Q4(Si(OSi)4) denotes Si species bound tetragonally to four other Si–O groups [31]. The percentage areas of different Si bonding in the wall structure of the samples prepared at different temperatures are given in table 3. As can be noted in table 3, when the synthesis temperature is increased, the percentage area of the Q4 increases with the concomitant decrease of Q3 and Q2. This confirms the enhancement of the condensation of silanol groups to Si–O–Si when the synthesis temperature of FDU-12 is high. It should also be noted that the decrease in silanol groups in the samples prepared at high temperature offers a high hydrophobic surface which is good for the adsorption of biomolecules [31]. In addition, a high degree of silanol condensation in the wall structure within a short duration of time at high temperature particularly favours other application possibilities for FDU-12 with cage-type pores because these highly cross-linked siloxane moieties offer high hydrothermal stability due to strong Si–O–Si bonding but a lower number of Si–OH groups in the walls.

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.