Reviewed by Lexie CornerJan 27 2025
A study published in Advanced Sustainable Systems by researchers at the University of Duisburg-Essen presents a new method for purifying polluted water.
Image Credit: AG Phykologie/CCAC
European water bodies face significant contamination, with over half classified as heavily polluted. This is attributed to the extensive use of up to 70,000 chemicals daily in European industry and agriculture.
The study demonstrates that chemically modified fossil remains of diatoms, a type of algae, can effectively remove pollutants from water.
Researchers have identified more than 500 harmful chemicals from industrial and agricultural sources in European rivers. Under the leadership of Junior Professor Dr. Anzhela Galstyan, the team is exploring the use of algae to target and eliminate these contaminants.
Diatoms are microscopic single-celled organisms that live in water and possess a cell wall made of silica (silicon dioxide). Thanks to its porous structure, it can absorb a wide variety of pollutants.
Dr. Anzhela Galstyan, Junior Professor, University of Duisburg-Essen
In the study, researchers evaluated the use of diatom shells for removing two major contaminants associated with the textile industry: methylene blue and methyl orange. To enhance adsorption capacity, diatomaceous earth was chemically modified by introducing functional groups to its surface.
“This could easily be implemented on an industrial scale,” noted Galstyan.
The material was tested under various conditions, including different salt concentrations and pH levels. The results showed consistent contaminant removal performance. For comparison, silica, a material commonly used in water purification, was also tested.
Diatomaceous earth outperformed silica significantly. Within an hour, up to 100 % of methylene blue was removed by diatomaceous earth, while silica achieved 88 % removal over the same period. For methyl orange, both materials absorbed approximately 70 % of the pollutant.
Galstyan added, “We see diatomaceous earth as an eco-friendly and cost-effective solution for water treatment.”
A key advantage of diatomaceous earth is its renewability. Unlike activated carbon, a widely used filter material, algae require minimal energy for cultivation and are a sustainable resource.
The researchers are now exploring the integration of diatomaceous earth into water purification membranes. The University of Duisburg-Essen, which houses the world’s largest algae collection, provides an ideal setting for advancing this eco-friendly technology.
Journal Reference:
Ojike, A. C., et al. (2025) Surface‐Functionalized Diatoms as Green Nano‐Adsorbents for the Removal of Methylene Blue and Methyl Orange as Model Dyes from Aqueous Solution. Advanced Sustainable Systems. doi.org/10.1002/adsu.202400776.