Lignin-Mediated Preparation of Hierarchical ZSM‑5
Catalysts and Their Effects in the Catalytic Co-pyrolysis of Softwood
Biomass and Low-Density Polyethylene Mixtures
posted on 2021-09-03, 18:33authored byMoriko Qian, Hanwu Lei, Yunfeng Zhao, Elmar Villota, Erguang Huo, Chenxi Wang, Xuesong Zhang
Biomass-mediated
modification in zeolite synthesis has outstanding
potential in directing new porous structures and improved catalyst
properties. This study reports the preparation of hierarchical ZSM-5
catalysts by a successive treatment of desilication and lignin-mediated
reassembly. The changes in physicochemical properties of the hierarchical
ZSM-5 including crystallinity, porosity, acidity, and morphology were
characterized by foreseeing the application of lignin as a green template.
The hierarchical pore system containing moderately strengthened acidity
was directed with 1 wt % lignin addition, which attained more desirable
products and less solid residue than the microporous ZSM-5. The catalytic
conversion of biomass and plastic feedstocks was performed using analytical
and bench-scale reactor systems to evaluate desired mixtures and product
distribution. It was found that the surface and intracrystalline mesopores
in hierarchical ZSM-5 were beneficial for the conversion of macromolecules,
such as aromatic oxygenates and long-chain hydrocarbons. While the
plastic-derived olefins synergistically interacted with the biomass
derivatives within the pyrolytic vapor, the hierarchical structure
extended reactant accessibility from the catalyst surface into the
microporous channels and internal acid sites.