Work

Effect of steam-enriched CO2 atmosphere on the properties of biochar derived from food waste gasification

Year: 2026

Type: article

Abstract: Agro-industrial residues (food waste) represent a significant source of feedstocks that possess, both material and energy potentials. This study examined the valorisation of sunflower husks, buckwheat husks, cherry stones, and tomato waste through gasification under CO 2 and steam-enriched CO 2 atmospheres at 900 °C. The biochemical composition of these feedstocks was characterised by 28–78 wt% lignocellulosic fractions content and from 0.6 to 17 wt% of lipids. Solid residue (biochar) yields ranged from 9.1% (sunflower husks, CO 2 + H 2 O) to 28.1% (tomato waste, CO 2 ), while carbon content reached up to 88 wt% for cherry stone. The introduction of steam reduced the yield by 35%, but significantly increased the specific surface area from 410 to 881 m 2 /g and from 224 to 823 m 2 /g for buckwheat husks and sunflower husks, respectively. Lignin-rich feedstocks produced more aromatic and thermally stable structures (R 50 > 0.45). FT-IR spectra confirmed the loss of hydroxyl and carbonyl groups and formation of condensed aromatic structures. These findings show that biochemical composition of food waste significantly influences carbonisation behaviour and surface functionality. Furthermore, they provide a framework for optimizing gasification conditions to produce biochars that can be used as bio-based materials in catalysis, adsorption, and carbon sequestration.

Source: Renewable Energy

DOI: 10.1016/j.renene.2026.126291