A new study published in Biochar reports a sustainable membrane technology that converts microalgae-derived biochar into an advanced material for municipal wastewater treatment, offering a promising route to cleaner water and waste valorization.
Municipal wastewater contains a complex mixture of organic matter, nutrients, salts, and microorganisms. Among these pollutants, natural organic matter is particularly challenging because it can clog filtration membranes, reduce treatment efficiency, and contribute to the formation of unwanted by-products during disinfection. Membrane technologies are widely used in water treatment, but fouling remains one of their biggest barriers to long-term, cost-effective operation.
To address this challenge, researchers developed amine-functionalized biochar/cellulose acetate hybrid membranes using biochar derived from microalgae biomass. The biochar was chemically modified with amine groups through a one-step mussel-inspired polymerization and Schiff-base reaction. The resulting amine-functionalized biochar was then blended into cellulose acetate, a biodegradable polymer, to create hybrid ultrafiltration membranes.
"Our goal was to design a membrane that not only performs well, but also fits within a more sustainable materials cycle," said corresponding author Shadi W. Hasan. "By transforming microalgae biomass into a functional biochar filler, we can improve wastewater filtration while adding value to biological waste streams."
The team found that adding amine-functionalized biochar improved several key membrane properties. The hybrid membranes became more hydrophilic, more porous, and more negatively charged, all of which helped reduce foulant adhesion and improve water transport. Structural and chemical analyses confirmed that the functionalized biochar was successfully produced and incorporated within the cellulose acetate matrix.
Among the tested membranes, the one containing 4 wt.% amine-functionalized biochar showed the strongest overall performance. In municipal wastewater filtration, this membrane achieved a water flux of 169.1 L m⁻² h⁻¹ and 64.1% removal of natural organic matter, outperforming the pristine cellulose acetate membrane, which reached only 81.8 L m⁻² h⁻¹ and 31.1% removal.
The modified membrane also demonstrated complete bacterial removal during testing. In addition, it partially removed other common wastewater contaminants, including chemical oxygen demand, sulfate, phosphate, nitrate, ammonium, and magnesium. These results suggest that the membrane could provide broader benefits beyond organic matter control.
Membrane fouling resistance was another important outcome. After municipal wastewater filtration and simple cleaning with deionized water, the best-performing membrane showed a flux recovery ratio of 82.7%, indicating strong antifouling behavior without the need for harsh chemical cleaning.
"Fouling is a major limitation for membrane-based wastewater treatment," Hasan said. "The improved recovery and stable filtration performance suggest that biochar-based hybrid membranes can help make water treatment systems more durable and easier to operate."
The study also highlights the value of testing membranes with real municipal wastewater, rather than relying only on synthetic laboratory solutions. By demonstrating performance under more practical conditions, the work provides a stronger foundation for future scale-up and application.
The researchers conclude that microalgae-derived amine-functionalized biochar is a promising sustainable filler for next-generation hybrid membranes. The approach links biomass waste conversion with advanced water treatment, showing how renewable carbon materials could help build more efficient and environmentally friendly wastewater technologies.
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Journal Reference: Abuhasheesh, Y., Kumar, M., Abuhatab, F. et al. Amine-functionalized biochar/cellulose acetate hybrid membranes for sustainable municipal wastewater treatment. Biochar 8, 68 (2026).
https://doi.org/10.1007/s42773-026-00582-3
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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.
