This study introduces a novel and green solid-phase activization technology, which could significantly enhance the chemical reactivity of Si and Al species within kaolinite for zeolite synthesis. Based on this technology, a cost-free kaolinite-rich soil is successfully transformed into A-type zeolite (LTA), a famous and highly productive commercial zeolite. Specifically, solid-phase activization only comprises a green solid-phase ageing step at room temperature and a straightforward heating step at 100°C, showing a progressive activization characteristic. Firstly, the aluminosilicates are fully encapsulated and eroded by the deliquescent NaOH colloids during solid-phase ageing process, occurring preliminary depolymerization. Then upon heating operation, the depolymerization strength of aluminosilicates would be dramatically enhanced, transforming most original Q 3 Si and Al VI species within the soil into Q 0 , Q 1 Si, and Al IV species that are highly desired for zeolite synthesis. Finally, through conventional hydrothermal reaction, the activizated soils could be seamlessly converted into LTA. Compared to the current activization technologies, solid-phase activization exerts superior advantages in terms of activization efficacy, NaOH consumption, energy expenditure, and equipment requirements. Overall, this work shows a novel activization approach for greener aluminosilicate depolymerization and cost-effective LTA synthesis. More remarkably, it significantly broadens the diversity and source options of Si and Al raw materials for zeolite preparation, profoundly enhancing the application potential of silica-alumina minerals within soil and fostering a vast horizon for industries reliant on activizated Si and Al species.
Kai Fan,Qinming Wu,Shuo Liu,Haiyu Kong,Sen Wang,Eduard Kunkes,Trees De Baerdemaeker,Andrei-Nicolae Parvulescu,Nils Bottke,Toshiyuki Yokoi,Dirk E. De Vos,Xiangju Meng,Weiping Zhang,Feng-Shou Xiao
Adjusting location and distribution of Al sites in the zeolite framework is critical for catalysis, and typical strategies include using zeolites as starting Al source. However, this approach is still challenging for aluminosilicate ITH zeolite. Herein, the distribution of Al species in the framework of ITH was efficiently regulated by implementing LTA zeolite as the aluminum source added in the starting gels (LTA-ITH). The obtained LTA-ITH zeolites have similar nanosheet morphology, textual parameters, and acidic properties to those of conventional ITH synthesized from boehmite (C-ITH), while the results of 27 Al MAS NMR spectra and 1-hexene cracking indicate that they have a different Al distribution. The use of LTA zeolite in starting gel is favorable for the formation of more Al species in sinusoidal and straight channels, compared with the C-ITH. Catalytic tests in the conversion of methanol to light olefin showed that LTA-ITH exhibited enhanced catalyst lifetime and propene selectivity compared with the C-ITH, which is reasonably attributed to the different locations of Al species in their respective ITH frameworks.
危险品化学品经营许可证（带存储）