Method for synthesizing ordered mesoporous molecular sieve by anion effect
A mesoporous molecular sieve and anion technology, applied in the direction of crystalline aluminosilicate zeolite, can solve the problem of inability to improve hydrothermal stability, and achieve the effect of good hydrothermal stability
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Embodiment 1
[0026] Example 1: Hydrothermal synthesis of hydrothermally stable ordered mesoporous molecular sieve SBA-15-S.
[0027] Dissolve 0.8g of triblock copolymer (P123) in 25mL of deionized water, stir well, add 3mL of hydrochloric acid, stir until clarified, then add 2.08g of silicon source tetraethyl orthosilicate (TEOS). The above solution was stirred at 40°C for 20 hours, then the pH value was adjusted to 7 with ammonia water and 2.64 g of ammonium sulfate was added, the mixture was transferred to a reaction kettle, and stood at 100°C for 48 hours. The product was extracted and dried at room temperature to obtain the original powder. Raise the temperature of the original powder to 550°C in the air and keep it for 5 hours to remove the surfactant and obtain open channels. This molecular sieve is named SBA-15-S.
[0028] From the results of small angle X-ray diffraction (see figure 1 ), SBA-15-S has regular two-dimensional hexagonal channels. figure 1 Among them, A is SBA-15-S ...
Embodiment 2
[0029] Example 2: Hydrothermal synthesis of a hydrothermally stable ordered mesoporous molecular sieve SBA-15-U.
[0030] Dissolve 0.8g of triblock copolymer (P123) in 25mL of deionized water, stir well, add 3mL of hydrochloric acid, stir until clarified, then add 2.08g of silicon source tetraethyl orthosilicate (TEOS). Stir the above solution at 40°C for 3-4 hours, then add 3-6g of urea, raise the temperature of the solution to about 90°C, wait until the pH value of the solution gradually changes to 5-6, move the mixture to the reaction kettle, and put it under the condition of 100°C Leave for 48 hours. The product was extracted and dried at room temperature to obtain the original powder. Raise the temperature of the raw powder to 550°C in the air and keep it for 5 hours to remove the surfactant and obtain open channels. This molecular sieve is named SBA-15-U.
[0031] Figure 4 Among them, A is SBA-15-U obtained after calcination, and B is SBA-15-U after calcination and t...
Embodiment 3
[0032] Example 3: High temperature synthesis of hydrothermally stable ordered mesoporous molecular sieve SBA-16-S.
[0033] 0.8g tri-block copolymer (F127) was used as a template, and other feeding steps and treatment methods were the same as in Example 1, and the obtained product was designated as SBA-16-S. From the low-angle X-ray diffraction pattern ( Figure 6 ) and high-resolution transmission electron microscopy, it can be seen that the product SBA-16-S has regular cubic mesopores. 29 Si NMR results show that in SBA-16-S raw powder, fully condensed silicon species Si(OSi) 4 It occupies a large proportion, which shows that the silicon species in the SBA-16-S raw powder is also highly condensed. Therefore, SBA-16-S also exhibited good hydrothermal stability, maintaining regular cubic mesoporous channels after being treated with water vapor at 780 °C for three hours.
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