University of Haute Alsace (UHA), CNRS, Axe Matériaux à Porosité Contrôlée (MPC), Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361, F-68093 Mulhouse, France.
University of Strasbourg (UniStra), F-67000 Strasbourg, France.
Molecules. 2020 May 31;25(11):2563. doi: 10.3390/molecules25112563.
Binderless pure silica zeolites (zeosils) spheres and hollow spheres with a diameter of 20 µm composed of silicalite-1 nanosheets particles were prepared by pseudomorphic transformation of spherical silica beads using different temperatures (110, 130, and 150 °C) and treatment times (1-5 days) in order to adapt the local dissolution rate of silica to the crystallization rate of silicalite-1 nanosheets allowing to preserve the initial morphology of the silica beads. Fully crystalline beads of 20 µm were obtained at 110 °C for 5 days, whereas hollow spheres similar in size were synthesized at higher temperatures. The crystallization process seems to begin at the outer surface of the amorphous silica beads and spreads with the time in the interior of the beads leading to a dissolution of the inner amorphous part of the beads to create zeosil hollow spheres for the highest treatment temperatures (130 and 150 °C). The dissolution rate of the inner amorphous part of the beads increases by increasing the hydrothermal treatment temperature from 130 to 150 °C. The silicalite-1 beads synthesized at 110 °C for 5 days showed to be promising for rapid molecular decontamination by adsorbing n-hexane in larger amount than the silicalite-1 conventional big crystals in powder forms.
无定形硅沸石（zeosils）球体和 20 µm 直径的空心球体由不同温度（110、130 和 150°C）和处理时间（1-5 天）下的球形二氧化硅珠的拟晶转变制备而成，以适应二氧化硅的局部溶解速率与 silicalite-1 纳米片的结晶速率相匹配，从而保持二氧化硅珠的初始形态。在 110°C 下处理 5 天可得到完全结晶的 20 µm 珠，而在较高温度下则合成了类似尺寸的空心球体。结晶过程似乎从无定形二氧化硅珠的外表面开始，并随着时间的推移在珠内扩展，导致珠内无定形部分的溶解，从而为最高处理温度（130 和 150°C）下合成 zeosil 空心球体。随着水热处理温度从 130°C 升高到 150°C，珠内无定形部分的溶解速率增加。在 110°C 下处理 5 天合成的 silicalite-1 珠在快速分子脱污染方面表现出很大的潜力，因为它们比粉末形式的常规大晶体 silicalite-1 能够吸附更多的正己烷。
