Accelerated Growth of Mesoporous Zeolite Via Enlarging Gel-Liquid Interfacial Area Using Rotating Packed Bed

Typically, zeolites are hydrothermally synthesized in the sodium-rich dense hydrogel systems with a relatively long crystallization time in industry. The fast and economical synthesis of zeolites is still a big challenge. Herein, we develop a universal method to tackle this issue using the rotating packed bed (RPB). An interesting phenomenon is found that gel-liquid interfacial areas in the zeolite precursor are obviously enlarged when RPB is employed, and thus the following crystallization rates of zeolites are greatly improved, especially for the initial growth process. Also, we successfully control the growth rates of zeolite by changing the rotation speeds of RPB for adjusting the gel-liquid interfacial areas. Furthermore, we find that the transfer rate of OH - and hydrated sodium ions from liquid part to gel phase is also enhanced by RPB in the initial nucleation process, which greatly promotes the nucleation rate of zeolites. The density function theory (DFT) calculations demonstrate that hydrated sodium ions can induce the dehydrogenation of Si-OH to generate reactive oxygen radicals, thus lowering the energy barrier of the polymerization reaction and consequently accelerating the nucleation process. Besides, mesoporous NaY, NaZSM-5, and NaA zeolites are successfully synthesized by the RPB-enhanced-interface strategy, and their crystallization processes are greatly accelerated, indicating the universality of this new strategy