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

The combination of two modification techniques developed for the ZSM-5zeolite, 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 °C and compared with the parent ZSM-5and the modified intermediate productsdesilicated ZSM-5(DeZSM- 5) and LaZSM- 5. Among the catalysts tested, DeLaZSM- 5showed the highest catalytic degradation rate. In addition, on DeLaZSM- 5the 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-5zeolite. The high catalytic activity of DeLaZSM- 5could 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 acidsites.