Biomass Valorization through Catalytic Pyrolysis Using Metal-Impregnated Natural Zeolites: From Waste to Resources

Area of Science:

• Catalysis
• Biomass Conversion
• Green Chemistry

Background:

• Catalytic biomass pyrolysis offers a sustainable route to petroleum-alternative chemicals.
• Lignocellulosic biomass is an abundant renewable resource.
• Production of aromatic compounds like benzene, toluene, and xylene (BTX) is a key goal.

Purpose of the Study:

• To evaluate BTX production from catalytic pyrolysis of Pinus radiata (PR) and Eucalyptus globulus (EG).
• To investigate the efficacy of modified Chilean natural zeolite (NZ) catalysts.
• To understand the role of catalyst modification (double ion exchange and metal impregnation) in enhancing aromatic yields.

Main Methods:

• Characterization of natural zeolite (NZ), double ion-exchanged zeolite (H2NZ), and metal-impregnated zeolites (Cu5H2NZ, Ni5H2NZ) using techniques like XRD, TPD-NH3, and SEM-EDS.
• Analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) to analyze pyrolysis products.
• Evaluation of catalyst performance at varying biomass/catalyst ratios.

Main Results:

• XRD and SEM-EDS confirmed successful metal oxide presence and impregnation on the zeolite catalysts.
• Modified zeolites significantly reduced oxygenated compounds (phenols, esters, ketones).
• Ni5H2NZ catalyst dramatically increased BTX yields: PR from 2.92% to 20.89% and EG from 2.69% to 30.53%.

Conclusions:

• Modified Chilean natural zeolites are effective catalysts for producing aromatic hydrocarbons from biomass pyrolysis.
• The acidic sites on the modified zeolites facilitate crucial deoxygenation and aromatization reactions.
• This catalytic process shows high potential for converting biomass into valuable, bio-sustainable chemicals, improving pyrolysis vapor quality.