Clean water is essential for human health, agriculture, and ecosystems, yet many industrial waste streams still contain dyes, nutrients, salts, and other contaminants that are difficult to remove efficiently. In a new study published in Sustainable Carbon Materials, researchers developed a sawdust based adsorbent that could help turn low value wood waste into a practical material for wastewater treatment.
The study, titled "Adsorption of methylene blue dye and potato processing wastewater using bimetallic activated hydrochar: batch and fixed bed column experiments," reports the synthesis of Fe Cu bimetallic activated hydrochar, named MAHC, from sawdust through hydrothermal carbonization, KOH activation, and hybridization with iron and copper. The material was tested first against methylene blue, a widely used dye found in textile, paper, cosmetic, and medical applications, and then in a fixed bed column using both dye solution and real wastewater from a potato processing facility.
"Our goal was to design an adsorbent that is not only effective in laboratory dye removal tests, but also relevant to continuous wastewater treatment," said corresponding author Dr. Yulin Hu. "By combining hydrochar activation with iron and copper active sites, we created a porous carbon material that can interact with pollutants through multiple pathways."
Under optimized batch conditions, MAHC achieved a maximum methylene blue adsorption capacity of 1,635.28 mg/g at pH 10, with 50 ppm methylene blue, 5 ppm MAHC, and 44 °C. The adsorption behavior was best described by the Freundlich model, suggesting that methylene blue molecules were adsorbed on a heterogeneous surface through multilayer adsorption rather than a single uniform layer. The adsorption kinetics were better fitted by the pseudo second order model, indicating that the process involved complex surface interactions.
Characterization showed that MAHC had a high specific surface area of 1,266.1 m²/g and a microporous structure. The team found that pore filling and surface interactions were the dominant removal mechanisms, including interactions between methylene blue and Fe and Cu active sites, as well as π π interactions between the dye molecules and the carbon framework. Electrostatic attraction appeared to play only a minor role.
"The results suggest that engineered hydrochar can do more than simply trap pollutants in pores," said corresponding author Dr. Quan Sophia He. "The introduced metal sites and carbon structure work together, which helps explain the strong adsorption performance observed in this study."
Importantly, the researchers also evaluated MAHC in fixed bed column experiments, a format closer to practical treatment systems than conventional flask tests. The column reached a breakthrough point at 165 minutes for methylene blue solution and 360 minutes for real potato processing wastewater, demonstrating the material's potential under continuous flow conditions.
The authors note that more work is needed before real world application. Future studies should compare MAHC directly with commercial activated carbon, evaluate other biomass feedstocks, and examine the material's stability and recyclability across repeated treatment cycles. The study also found that higher temperature improved adsorption, so improving performance at or near room temperature will be important for industrial use.
Still, the findings point to a promising waste to resource strategy: converting sawdust into a functional carbon material for water cleanup. By linking biomass recycling with wastewater treatment, the work offers a step toward more sustainable and circular pollution control technologies.
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Journal reference: Jalilian M, Nawazish B, Taborda R, He QS, Hu YL. 2026. Adsorption of methylene blue dye and potato processing wastewater using bimetallic activated hydrochar: batch and fixed bed column experiments. Sustainable Carbon Materials 2: e019 doi: 10.48130/scm-0026-0014
https://www.maxapress.com/article/doi/10.48130/scm-0026-0014
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About Sustainable Carbon Materials :
Sustainable Carbon Materials (e-ISSN 3070-3557) 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.
