Hierarchical ZSM‑5 Materials for an Enhanced Formation of Gasoline-Range Hydrocarbons and Light Olefins in Catalytic Cracking of Triglyceride-Rich Biomass

A hierarchical ZSM-5 material with a high fraction of mesoporosity coupled to well-preserved intrinsic zeolite characteristics has been successfully prepared by postsynthesis modifications involving optimization of base treatment and subsequent strong acid washing of commercial Al-rich ZSM-5 (parent ZSM-5). The resulting hierarchical ZSM-5 material was thoroughly characterized before being tested in the cracking of triglyceride-rich biomass, i.e., model feedstock triolein and real feedstock waste cooking oil under fluid catalytic cracking conditions. The results show that the introduction of intracrystalline mesoporosity enhances the utilization of zeolite acid sites by the enlarged external surface, leading to an increased conversion. At the same time, it partially suppresses the undesired secondary reactions by shortening micropore diffusion path lengths. With such a hierarchical ZSM-5 material, higher selectivities toward the desired products, i.e., gasoline-range hydrocarbons and light olefins, than with commercial ZSM-5 have been achieved