Enhanced aromatics production from cassava residue pyrolysis via optimizing zeolite configuration

This study presents a novel lanthanum-modified hollow hierarchical ZSM-5 for the highly selective pyrolysis of cassava residue (CR) into value-added aromatics. The optimized 0.5LaH catalyst gives a unique hollow architecture with interconnected micro-meso-macro pores and abundant Brønsted acid sites via selective desilication and La³⁺-induced hydroxyl polarization, thereby greatly contributing to the mass transfer and selective pyrolysis. Remarkably, hierarchical porosity facilitates the diffusion of molecules with larger kinetic diameters, increasing the effective diffusion coefficients of furfural (6.2 Å) and benzene (6.7 Å) by 58 % and 257 %, respectively. As a result, aromatics yield of up to 48.1 wt% is achieved from CR pyrolysis over 0.5LaH. Kinetic analysis confirms that optimizing mass transfer synergistically with La modification lowers the apparent activation energy from 320.3 kJ/mol to 232.2 kJ/mol, which also helps the inhibition of coke formation. The present research provides a sustainable strategy for lignocellulosic wastes into aromatics via rationally designed hierarchical zeolites.