LAUSR

Abstract The CHA zeolites were synthesized using coke-free and coke-containing spent MFI zeolites via the steam-assisted dry gel conversion method. The results indicate that the coke within the spent MFI precursor has played a vital role in preventing the crystal structure from collapse in a steam condition with the excess synthesis time of 3 days, but the SSZ-13 obtained from coke-free MFI zeolites suffered from a partial collapse in the same synthetic conditions. These could be attributed to the surrounding of some hydrophobic coke onto the surface of SSZ-13 crystallite during the synthesis. Besides, the sample produced from coke-containing spent MFI had better catalytic stability in methanol to olefins as well. Graphic Abstract SSZ-13 synthesized from coke free MFI (a, c) and coke containing MFI (b, d).