A new study has developed a sustainable filtration technology that transforms microalgae waste into high-performance membranes capable of removing pollutants and bacteria from wastewater. The innovation could offer a greener and more efficient solution for municipal water treatment.
Researchers created a novel material by converting microalgae biomass into biochar and then modifying it with amine functional groups. This engineered biochar was incorporated into biodegradable cellulose acetate membranes, producing hybrid filters with enhanced purification performance.
"Our goal was to turn waste into value while addressing one of the most pressing environmental challenges, which is water pollution," said the study's lead author. "By functionalizing biochar and integrating it into membranes, we achieved both high filtration efficiency and improved resistance to fouling."
Water treatment systems often struggle with natural organic matter, a complex mixture derived from decomposing plants and animals. These compounds can clog filtration systems, reduce efficiency, and form harmful byproducts during disinfection. Traditional membranes are prone to fouling, which increases operational costs and limits long-term use.
The new hybrid membranes overcome these challenges through improved surface chemistry and structure. The amine-functionalized biochar enhances membrane hydrophilicity, porosity, and surface charge, all of which contribute to better pollutant rejection and water flow.
In laboratory tests, the optimized membrane achieved a water flux of 169.1 liters per square meter per hour while removing 64.1 percent of natural organic matter from real municipal wastewater. This represents a substantial improvement compared to conventional cellulose acetate membranes, which showed lower flux and only 31.1 percent removal efficiency under similar conditions.
Beyond organic contaminants, the membranes also demonstrated complete removal of bacteria, highlighting their potential for improving water safety. Additional tests showed partial removal of nutrients and inorganic pollutants such as nitrate, phosphate, and sulfate.
A key advantage of the new material is its resistance to fouling. The membranes maintained strong performance after repeated use, with a flux recovery ratio exceeding 80 percent after simple cleaning. This durability is critical for real-world applications, where membrane fouling is a major limitation.
The researchers attribute the improved performance to a combination of factors. The functionalized biochar creates a more hydrophilic surface that attracts water while repelling contaminants. At the same time, the membrane's negative surface charge enhances electrostatic repulsion against organic molecules, reducing their accumulation.
Importantly, the study demonstrates that agricultural or biological waste can be repurposed into advanced materials for environmental remediation. Microalgae, which are widely cultivated for biofuels and bioproducts, generate large amounts of residual biomass. Converting this waste into biochar provides a sustainable pathway for resource recovery.
Unlike many previous studies that rely on synthetic test solutions, this work validated the membrane performance using real municipal wastewater, strengthening its practical relevance.
The findings suggest that biochar-based hybrid membranes could play a significant role in future water treatment systems, particularly as demand for clean water continues to rise globally.
The researchers note that further work is needed to scale up production and evaluate long-term performance in full-scale treatment facilities. However, the results provide a promising foundation for developing cost-effective and environmentally friendly filtration 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.
