The sustainable conversion of wood into value-added carbonaceous biochar requires a comprehensive understanding of how feedstock diversity and processing conditions shape biochar functional properties and its carbon footprint. Here, we present a comprehensive comparative study of five wood species including four hardwoods (eucalyptus, mahogany, red alder, and red beech) and one softwood (pine), that are pyrolyzed at 350, 550, and 750 °C. The woody biomass was selected as representative examples of forest biomass sources with rotation periods ranging from 12 and 120 years. Higher pyrolysis temperature produced systematic carbon enrichment in the biochar, loss of oxygenated groups, and progressive aromatization, as confirmed by CHNSO, FTIR, and XPS analyses. Microscopy imaging revealed temperature-driven transitions from intact lignocellulosic cell walls to highly fragmented, hierarchical pore networks, with hardwoods developing more extensive porosity than pine. Surface and bulk analyses prove that biochar yields were highest for lignin-rich woods, whereas carbohydrate-rich species produced more oxygen-functionalized surfaces at intermediate temperatures. Dynamic life cycle assessment (LCA) was conducted by applying time-dependent characterization factors to emissions and removals of biogenic carbon. Depending on the woody species, pyrolysis temperature, and dynamic accounting for biogenic carbon emissions and removals, the climate change of biochar varies from −1.38 to +8.82 kg CO 2 -eq.·kg −1 . Altogether, this work provides a unified framework for predicting biochar functional properties and environmental sustainability. • Pyrolysis is conducted for five wood species at 350, 550, and 750 °C. • Selected forest biomass has rotation periods expanding from 12 to 120 years. • High yields are for lignin-rich woods, carbohydrate-rich species produce oxygen-functionalized surfaces. • Hardwoods develop open and heterogeneous pore networks, pine biochar remains fibrous. • Life cycle assessment is done with a dynamic accounting approach for biogenic carbon.
Baniasadi et al. (Sun,) studied this question.