Solventless synthesis of AEL-type aluminophosphate molecular sieve from mechanochemically pretreated low-templated reactants

One of the main obstacles that hamper the application of zeolites is the high consumption of expensive structure-directing agent. Herein, we reported the mechanochemisty-mediated solventless synthesis of AlPO4-11 aluminophosphate molecular sieve with low dosage of diisopropylamine (DIPA) as the structure-directing agent. The influences of DIPA/Al2O3 ratio, fluoride ions, seed crystals and high-energy mechanochemical pretreatment on the synthesis of AEL-type zeolite were investigated in detail. Both DIPA and fluoride ions are indispensable for the successful synthesis of AEL phase. The resultant AEL molecular sieves were characterized by XRD, SEM, TG-DTA, CHN elements analysis, and N2 physisorption. The results indicate that the introduction of seed crystals cannot improve the phase purity and crystallinity of the resulting products. On the other hand, high-energy mechanochemical pretreatment not only can affect the morphology of AEL zeolite, but more importantly, can also reduce the consumption of structure-directing agent.