From Peanut Shell to 2,5-Dimethylfuran: The Role of Zr-Micro/Mesoporous Zeolites

Catalytic pyrolysis of biomass is a promising process for the conversion of agricultural residues into renewable bio-oils, wherein zeolites play a key role in their upgrading. In this work, peanut shell pyrolysis was catalysed by micro/mesoporous ZSM-11 zeolites modified by the incorporation of zirconium. Mesopores were generated in the microporous zeolitic structure by post synthesis alkaline treatment using potassium hydroxide as basic medium. The effect of this treatment and its parameters were studied in detail. The obtained materials were extensively characterized. Results showed that micro/mesoporous ZSM-11 zeolites maintained their crystalline structure after the desilication process and presented excellent textural properties, such as 30% higher BET surface and 370% higher mesopore volume. Zirconium incorporation increased the amount of Lewis and Brønsted acid sites. Pyrolysis tests in presence of Zr-zeolites produced 2,5-dimethylfuran (DMF), a potential biofuel with high energy density, among other high value products for the chemical industry. Particularly, micro/mesoporous zeolite modified with Zr resulted in 25 wt% selectivity to DMF in bio-oil, then is presented as an excellent catalyst for pyrolysis of agricultural wastes.