Circular carbon materials from organic waste: Life cycle comparison with fossil-derived carbon

The growing demand for carbon-based materials for environmental applications has increased interest in renewable and waste-derived feedstock as alternatives to fossil resources. However, the environmental implications of producing these materials can vary substantially depending on the feedstock and thermochemical conversion route. In this study, a cradle-to-gate life cycle assessment was conducted to compare the environmental performance of carbon materials produced from organic residues through slow pyrolysis with that of petroleum coke-derived carbon produced by carbonization. The assessment considered material and energy inputs, direct process emissions, and electricity and natural gas consumption, using the ReCiPe 2016 framework. Results showed that the biomass-based pathway required substantially less electricity and natural gas than the petroleum coke pathway, resulting in a 93.27% reduction in indirect CO 2 emissions associated with electricity consumption and approximately 94% lower greenhouse-gas emissions associated with natural gas use. However, this environmental advantage was not consistent across all impact categories. The biomass pathway showed higher ozone-formation impacts for both human health and terrestrial ecosystems, highlighting a trade-off between greenhouse-gas mitigation and atmospheric environmental burdens. Sensitivity analysis further showed that process conditions and energy-related parameters can influence the environmental profile of the production pathways. Overall, the results indicate that waste-derived biochar can offer important environmental advantages at the production stage, but that its sustainability cannot be assessed from greenhouse-gas emissions alone.