SELECTIVE DEALUMINATION ZSM-5 ZEOLITE BY A NOVEL METHOD FOR ENHANCEMENT OF STABILITY

The synthesis of mesopores along with micropores, by templates of carbon nanotube has produced different composite structures for ZSM-5 zeolite. Dealumination of mesopores withtrichloroacetic acid (TCA) has been done selectively. Because of TCA molecules size, it just has diffused in mesopores and so, micropores were not dealuminated. As a result of the removal of aluminum atoms from the zeolite structure, empty spaces were created in the catalyst. If silicon atomsreplace in the empty spaces then the mesoporous structure gets similar to silicate that does not have any catalytic properties. Silicon atoms were extracted with a unique method and replaced in the empty spaces of the extracted aluminum atoms from the mesoporous structure. Therefore, by changing of the mesopores geometry and properties with micropores, the amount of coke was reduced from 14% for HZSM-5 to 3%, for the modified zeolite

Keywords:

Mesopores , Carbon nanotube , ZSM-5 zeolite , Dealumination