Can one material clean up industrial waste and pharmaceuticals from water? A new study indicates it can, at a surprisingly low cost.
Study: Engineered biochar for simultaneous removal of heavy metals and organic pollutants from wastewater: mechanisms, efficiency, and applications. Image Credit: caltili/Shutterstock.com
Engineered biochar is gaining attention as a clean, cost-effective solution to address one of the most complex environmental challenges: simultaneously removing heavy metals and organic pollutants from wastewater.
A recent review published in Biochar X explores how functionalized biochar can support safer water treatment by capturing these persistent contaminants through enhanced adsorption mechanisms.
The authors outline not only how engineered biochar works but also what makes it effective and where further research is needed to bring it into widespread use.
Water Pollution from Industrial and Urban Sources
Urban growth, agricultural intensification, and industrial activities have led to a surge in water pollution. Heavy metals such as lead (Pb2+), cadmium (Cd2+), and chromium (Cr6+) are especially problematic due to their toxicity and persistence in aquatic environments.
At the same time, organic contaminants like dyes, antibiotics, phenolic compounds, and perfluorinated substances pose risks ranging from hormone disruption to antibiotic resistance.
When these pollutants coexist in water, they can form new toxic compounds through complexation, creating even greater health hazards.
Traditional treatment methods, including membrane filtration, ion exchange, and advanced oxidation, are often effective but come with high costs and technical barriers.
Biochar offers a low-cost, adaptable alternative. Produced from biomass via pyrolysis, biochar is a porous, carbon-rich material with a natural ability to adsorb pollutants.
What Sets Engineered Biochar Apart
While raw biochar has some pollutant-binding capacity, its performance can be significantly improved through chemical or physical modification. This process, known as functionalization, alters the surface chemistry and structure to better target specific contaminants.
The review categorizes engineered biochar into several forms based on these enhancements, including those combined with metal oxides, layered hydroxides, polymers, or graphene-based materials.
Each type of engineered biochar has distinct advantages. Metal oxide composites, for example, provide more active sites for heavy metal capture.
Biochars combined with polymers or graphene show increased stability and stronger binding capacity for organic compounds. Layered double hydroxide (LDH) composites can remove both types of pollutants through ion exchange and surface interactions.
The performance of each material depends on the preparation methods, types of pollutants, environmental pH, temperature, and contact time.
High Removal Capacities Demonstrated in Lab Studies
Laboratory results indicate that engineered biochar can effectively remove multiple contaminants with high efficiency.
A hydroxyapatite-modified cod bone biochar achieved an adsorption capacity of 714.24 mg/g for Pb2+ and 43.29 mg/g for diclofenac. In another case, a silicon dioxide/biochar nanocomposite removed 1,614.04 mg/g of methylene blue, demonstrating strong potential for industrial dye removal.
These high capacities are made possible by a range of mechanisms, including electrostatic attraction, pore filling, surface complexation, and a bridging effect in which pollutants facilitate each other’s adsorption.
However, the presence of multiple pollutants can sometimes reduce overall efficiency. Competitive adsorption, where contaminants vie for the same active sites, has been observed in several studies, highlighting the importance of tailoring biochar modifications to specific contamination scenarios.
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Practical Potential and Current Limitations
Engineered biochar is now being explored for use in industrial wastewater treatment systems, agricultural runoff management, and municipal water treatment. Its ability to target multiple pollutants at once, combined with relatively low production costs and the potential for regeneration, makes it a promising option for sustainable water purification.
Still, there are limitations. Regeneration efficiency can decline over repeated cycles, and some recovery methods risk releasing adsorbed pollutants back into the environment.
The economic feasibility of large-scale application depends on factors such as raw feedstock, modification process, and treatment conditions. In addition, real-world performance often varies from lab results, and more data from field trials are needed before it can be used in complex wastewater environments.
The review also emphasizes the need for life cycle assessments to evaluate the environmental footprint of engineered biochar, encompassing its production, use, and disposal. Understanding its full impact is crucial for ensuring that the solution itself does not create new problems.
Looking Ahead
Engineered biochar has demonstrated strong potential to support more sustainable and effective wastewater treatment, particularly where conventional methods are inadequate or prohibitively costly.
The dual ability to remove heavy metals and organic pollutants, combined with renewable sourcing and reusability, makes it an attractive option for integrated water treatment strategies.
Future research should focus on optimizing modification techniques, testing a wider range of biomass feedstocks, and conducting long-term field studies to confirm their durability and safety.
Economic evaluations and regulatory considerations will also be key in moving engineered biochar from research to real-world deployment.
If these challenges are addressed, engineered biochar could play a significant role in reducing pollution loads and improving water quality across various sectors.
Journal Reference
Wang, N. et al. (2025). Engineered biochar for simultaneous removal of heavy metals and organic pollutants from wastewater: mechanisms, efficiency, and applications. Biochar X, DOI: 10.48130/bchax-0025-0008. https://www.maxapress.com/article/doi/10.48130/bchax-0025-0008
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