Microalgae, microscopic organisms capable of absorbing carbon dioxide and harmful substances, have become a promising technology for the purification of contaminated waters.
A group of researchers from the University of Huelva (Spain) and the University of Umeå (Sweden) has designed a system that uses microalgae attached to a material made from residual sulfur and used cooking oil, forming a biofilm capable of trapping cadmium, copper, and lead.
A global problem: water contaminated by mining
The removal of heavy metals is essential, as they are among the most abundant pollutants in wastewater generated by mining extraction.
In Huelva, the mining tradition linked to the Tinto River has left a significant environmental footprint.
In northern Sweden, the largest rare earth deposit in Europe was recently discovered, posing new pollution challenges.
Resilient and effective microalgae
The microalgae used come from cold regions of northern Europe. Their ability to withstand low temperatures and low sunlight makes them particularly useful organisms for cleaning water in extreme conditions.
The study, published in the journal Green Chemistry, demonstrated that the system achieves:
Elimination of 95% of copper and cadmium.
Reduction of more than half of the lead in just 8 hours.
This is achieved thanks to microalgae of the genus Chlorella, spherical in shape and tiny in size (1 to 5 microns), capable of living in rivers, lakes, or wastewater.
Microalgae: a sustainable solution for cleaning contaminated waters.
A doubly sustainable system
The process can be repeated several times, making it a reusable and sustainable solution. Additionally, the captured metals can be recovered and reused, offering a double benefit:
Water cleaning.
Resource recovery.
The use of discarded materials such as cooking oil and residual sulfur reinforces the logic of the circular economy, transforming waste into natural filters.
New applications: beyond heavy metals
Researchers at the University of Huelva continue to explore the potential of microalgae. A study published in Toxics showed that some species can “feed” on organic compounds derived from petroleum, highly dangerous pollutants that affect fish, birds, and people.
These findings open the door to systems capable of eliminating a greater variety of pollutants, offering solutions where there is not yet a 100% effective treatment.
The research shows that microalgae can transform an environmental problem into an opportunity, mimicking natural processes to clean what human activity pollutes. This advancement not only contributes to the protection of aquatic ecosystems but also reinforces the need to invest in sustainable, circular, and environmentally friendly technologies.