Leucaena leucocephala and Montmorillonite Co-pyrolysis Biochar: A Study on Physicochemical Properties and Stability

Abstract

Leucaena leucocephala, an invasive toxic tree species, has threatened the survival of native plants in the Hengchun Peninsula, southern Taiwan. Due to the small-to-medium diameter, the utilization and processing of L. leucocephala is highly restricted, while its discarding accelerates carbon dioxide emission to the atmosphere. Biochar, produced from the pyrolysis of biomass under an inert atmosphere, is considered an effective carbon sequestration technique with high stability, which is important for long-term carbon storage and soil improvement. L. leucocephala biomass and montmorillonite were co-pyrolyzed under inert conditions, aiming to investigate the effects of different pyrolysis temperatures and montmorillonite blending ratios on biochar yield and carbon retention. Results showed improved biochar yield and carbon retention with increasing montmorillonite addition. Thermogravimetric analysis, nuclear magnetic resonance spectroscopy, and Fourier-transform infrared spectroscopy demonstrated enhanced stability of the modified biochars. The production of modified L. leucocephala biochar represents a promising technique for carbon dioxide sequestration and biochar stabilization, enabling the development of L. leucocephala utilization approaches.