Lee, et al (2024) Enhancing the Potential Application of Food-Waste BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More as a Sustainable Bio-Solid Fuel: Analysis of Post-Treatment and Combustion Behavior. Chemosphere. https://doi.org/10.1016/j.chemosphere.2024.143216

Food-waste biochar holds promise as a sustainable bio-solid fuel, potentially contributing to carbon neutrality efforts. However, its high content of problematic elements like sodium (Na), potassium (K), calcium (Ca), and chlorine (Cl) presents challenges for its practical use. A recent study explored how different organic acids—ascorbic, acetic, citric, and iminodiacetic acids—can be used to treat food-waste biochar, aiming to improve its fuel properties and reduce the emission of harmful pollutants during combustion.

The study found that these post-treatment processes effectively reduced the Cl content by about 92%, significantly enhancing the biochar’s suitability as a solid fuel. Notably, citric acid showed the highest potential in removing alkali and alkaline earth metals, particularly Ca, which also offers an opportunity for CO2 storage through indirect mineral carbonation. Acetic acid emerged as the most cost-effective option for biochar post-treatment, considering both economic and environmental factors.

Additionally, the research highlighted the role of organic acid treatments in altering the biochar’s chemical structure, improving its ability to re-adsorb Na and K. This re-adsorption is linked to a reduction in NOx emissions during combustion, making the treated biochar a more environmentally friendly fuel alternative.

While the study provides a promising pathway for the large-scale application of food-waste biochar as a bio-solid fuel, further research is necessary to optimize treatment conditions and fully realize its potential in sustainable energy production.