Argentine researchers use yerba mate to remove toxic chromium from water

Scientists at the National University of San Martín (UNSAM) in Argentina have developed a laboratory-scale method to remove toxic chromium from contaminated water using yerba mate extract. The process targets hexavalent chromium (Cr VI), a highly toxic and carcinogenic substance commonly found in industrial wastewater from leather, paint, steel, and cement production.

The method utilizes the reducing properties of compounds within a concentrated yerba mate extract to transform hexavalent chromium into trivalent chromium (Cr III), which possesses significantly lower toxicity. Following this transformation, the chromium is removed from the water. Initial experiments utilized clays to absorb the trivalent chromium, though researchers are currently working to replace clay with alginate spheres—a natural biopolymer derived from algae—to facilitate easier removal and potential use in filtration cartridges.

The research team has also implemented a predictive statistical model to optimize the process. This model calculates the precise amount of yerba mate extract required based on chromium concentration and pH levels, aiming to reduce material waste and improve efficiency for future industrial applications.