As global water resources face increasing pressure from industrial and agricultural activities, scientists are looking for innovative ways to clean and reuse wastewater sustainably. Researchers from Dalhousie University have now developed a simple and eco-friendly method to turn agricultural and forestry waste into powerful magnetic materials that can effectively remove toxic chemicals from water.
The study, published in Sustainable Carbon Materials, introduces magnetic carbon adsorbents made from two common waste products: flax shives and eucalyptus sawdust. These materials were converted into "hydrochar" through a process called hydrothermal carbonization, which transforms biomass into carbon-rich solids under heat and pressure. By adding iron during the process, the researchers created magnetic hydrochars that can be easily separated from treated water using a magnet, eliminating the need for costly filtration.
The new materials demonstrated outstanding performance in removing pentachlorophenol (PCP), a persistent and highly toxic pollutant commonly found in industrial and agricultural wastewater. Under optimal conditions, the flax-based hydrochar removed up to 95 percent of PCP, while the eucalyptus-based version achieved nearly 89 percent removal. Both materials maintained high efficiency through six reuse cycles, showing excellent stability and minimal loss of performance. Importantly, no iron leakage was detected, confirming that the materials are safe and environmentally friendly.
"Our goal was to develop a sustainable, low-cost, and reusable solution for treating wastewater contaminated with harmful chemicals," said lead author Tunnisha Dasgupta, a researcher at Dalhousie University's Faculty of Agriculture. "By using agricultural and forestry residues, we are not only cleaning water but also giving new value to waste materials."
The study highlights how simple modifications—such as incorporating iron during carbonization—can dramatically enhance the surface area, porosity, and adsorption capacity of bio-based materials. The resulting magnetic properties make them easy to collect and reuse, reducing both cost and environmental impact.
Senior author Dr. Quan (Sophia) He explained that the innovation represents a step forward for circular economy practices in water treatment. "This work shows how we can turn organic waste into advanced materials that protect our environment," she said. "The magnetic hydrochars are scalable, efficient, and align with global goals for sustainable water management."
By combining waste valorization with effective pollutant removal, the research provides a promising pathway toward greener wastewater treatment technologies that can benefit both industry and the environment.
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Journal reference: Dasgupta T, Rajput H, Perera P, Sun X, He Q. 2025. Sustainable carbon materials for magnetic adsorbent-based pentachlorophenol removal from wastewater. Sustainable Carbon Materials 1: e003 https://www.maxapress.com/article/doi/10.48130/scm-0025-0003
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About Sustainable Carbon Materials :
Sustainable Carbon Materials is a multidisciplinary platform for communicating advances in fundamental and applied research on carbon-based materials. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon materials around the world to deliver findings from this rapidly expanding field of science. It is a peer-reviewed, open-access journal that publishes review, original research, invited review, rapid report, perspective, commentary and correspondence papers.
