Nanosized zeolites have been found in extensive applications. Herein, a rapid two-step crystallization process (8 h) in a semisolid-like gel system, constructed by simply mixing and grinding solid silica gel, NaOH with TPAOH aqueous solution without extra water addition and any other additives, for the first time is demonstrated to synthesize nanosized silicalite-1 zeolites (∼66 nm) with high crystallinity and high product yield (>90%). The obtained nanosized silicalite-1 zeolites exhibit a large BET surface area (418 m² g^–1), a high micropore surface area (316 m² g^–1), and a rich micropore volume (0.14 cm³ g^–1). The rapid evolution process of nanosized zeolites could be decoupled into the nucleation stage at low temperatures and the crystallization stage at high temperatures during the two-step crystallization process. Importantly, the semisolid-like gel ensures fast nucleation. Moreover, in the later crystallization period, the fast crystal growth and inhibited ripening endow nanosized zeolite crystals with good crystallinity through a mass transfer-confined space. The obtained silicalite-1 zeolites were successfully applied in the preparation of (h0h)-oriented MFI zeolite membranes on hollow fibers, showing the flux up to 5.44 kg m^–2 h^–1 and the separation factor of 70 during the pervaporation test (5 wt % ethanol/water solution, 60 °C). This research develops a state-of-the-art synthetic approach for the efficient preparation of high-quality MFI-type nanozeolites.

中文翻译：

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通过两步结晶法在半固体状系统中从固体二氧化硅快速简便地合成纳米 Silicalite-1 沸石

纳米沸石已被广泛应用。在此，首次在半固体状凝胶体系中快速两步结晶过程（8小时），通过简单地混合和研磨固体硅胶、NaOH与TPAOH水溶液而构建，无需额外添加水和任何其他添加剂。证明可以合成具有高结晶度和高产物收率（> 90％）的纳米硅沸石-1沸石（∼66 nm）。所得纳米硅沸石-1沸石具有较大的BET表面积（418 m ² g ^–1）、较高的微孔表面积（316 m ² g ^–1）和丰富的微孔体积（0.14 cm ³ g ^–1）。在两步结晶过程中，纳米沸石的快速演化过程可以分解为低温成核阶段和高温结晶阶段。重要的是，半固体状凝胶可确保快速成核。此外，在结晶后期，快速的晶体生长和受抑制的熟化通过传质限制空间赋予纳米沸石晶体良好的结晶度。所获得的silalite-1沸石成功应用于制备( h 0 h )取向中空纤维MFI沸石膜，渗透汽化测试中通量高达5.44 kg m ^–2 h ^–1，分离因子为70 （5 wt% 乙醇/水溶液，60 °C）。这项研究开发了一种最先进的合成方法，可有效制备高质量的 MFI 型纳米沸石。