Engineered biochar boosts removal of toxic metals from water and soil
image: Functionalization of sawdust biochar using Mg-Fe-LDH and sodium dodecyl sulfonate enhanced its stability and immobilization capacity for Cd and Pb in contaminated water and soil
Credit: Xin Pan, Shaoping Kuang, Xiao Wang, Habib Ullah, Zepeng Rao, Esmat F. Ali, Qumber Abbas, Sang Soo Lee & Sabry M. Shaheen
A newly engineered biochar material may offer a powerful and sustainable way to clean up toxic metals from polluted water and soil, according to a recent study published in Biochar.
Researchers developed a modified biochar derived from sawdust that is capable of capturing hazardous metals such as cadmium and lead far more effectively than conventional biochar. These metals are widely recognized as priority pollutants due to their persistence, toxicity, and ability to accumulate in living organisms, posing serious risks to ecosystems and human health.
“Our goal was to design a more efficient and stable biochar that can tackle real-world contamination challenges,” said the study’s corresponding author. “This new material not only removes toxic metals more effectively but also remains stable in the environment, making it suitable for long-term applications.”
The research team enhanced traditional biochar by incorporating layered double hydroxides made of magnesium and iron, followed by treatment with a common surfactant, sodium dodecyl sulfonate. This dual modification created a unique micro and nano structured surface that significantly improved the material’s ability to bind pollutants.
Laboratory experiments showed that the engineered biochar achieved remarkable adsorption capacities. It removed up to 405 milligrams of lead and 673 milligrams of cadmium per gram of material, substantially outperforming both unmodified biochar and biochar modified with only one treatment. The improved performance was linked to multiple mechanisms working together, including surface precipitation, ion exchange, complexation, and hydrogen bonding.
Beyond water treatment, the material also demonstrated strong performance in soil remediation. When applied to contaminated soil, it transformed toxic metals from more mobile and bioavailable forms into stable forms that are less likely to be absorbed by plants or leach into groundwater. This shift is critical for reducing environmental risks and protecting food safety.
Another key advantage of the new biochar is its enhanced stability. Tests showed that the modified material resisted chemical oxidation and thermal degradation more effectively than conventional biochar. This suggests it could persist longer in soil, contributing not only to pollution control but also to carbon sequestration efforts.
“Stability is essential if we want to use biochar as a long-term environmental solution,” the authors noted. “Our results indicate that this modified biochar can serve both as a pollutant remover and a durable carbon storage material.”
The study also highlights the cost-effectiveness of biochar compared to traditional adsorbents such as activated carbon, making it a promising candidate for large-scale environmental applications. By using low-cost feedstocks like sawdust and relatively simple modification techniques, the approach aligns with circular economy principles and sustainable waste management.
While the findings are promising, the researchers emphasize the need for further field studies to evaluate the performance of the material under real environmental conditions and to better understand its interactions with soil ecosystems.
Overall, this work provides a new pathway for designing high-performance, carbon-based materials that address both pollution remediation and climate challenges. As concerns over heavy metal contamination continue to grow worldwide, such innovations could play a vital role in safeguarding water quality, agricultural productivity, and public health.
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Journal Reference: Pan, X., Kuang, S., Wang, X. et al. Functionalization of sawdust biochar using Mg-Fe-LDH and sodium dodecyl sulfonate enhanced its stability and immobilization capacity for Cd and Pb in contaminated water and soil. Biochar 7, 16 (2025).
https://doi.org/10.1007/s42773-024-00401-7
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.