Modifications of ZSM-5 zeolites and their applications in catalytic degradation of LDPE

摘要

The combination of two modification techniques developed for the ZSM-5 zeolite, i.e., desilication. and incorporation of lanthanum under microwave irradiation, has produced a highly efficient catalyst, DeLaZSM-5, for catalytic degradation of low-density,polyethylene (LDPE). Its performance on the degradation was studied at 390 degreesC and compared with the parent ZSM-5 and the modified intermediate products desilicated ZSM-5 (DeZSM-5) and LaZSM-5. Among the catalysts tested, DeLaZSM-5 showed the highest catalytic degradation rate. In addition, on DeLaZSM-5 the liquid yield was slightly increased and the isoparaffin index of the liquid was almost doubled, which indicated higher liquid quality compared with the parent ZSM-5 zeolite. The high catalytic activity of DeLaZSM-5 could be explained by its unique acidic properties with a sharp increase of the number and strength of weak acid sites and a decrease of strong acid sites. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 16]