When poisonous heavy metals like lead and cadmium escape from factories or mines, they can pollute the nearby soil. With no easy ways to remove these contaminants, fields must be cordoned off to prevent these toxins from entering the food chain where they threaten human and animal health.
According to the Environmental Protection Agency, heavy metals have been found at thousands of locations nationwide. While some have been cleaned up through a combination of federal, state and private efforts, the need remains for new technologies to address heavy metal contamination.
Now a research team led by Stanford materials scientist Yi Cui has invented a way to wash heavy metals from contaminated soils using a chemical process that’s a bit like brewing coffee.
As they describe June 4 in Nature Communications, the researchers started by rinsing contaminated soil with a mixture of water and a chemical that attracts heavy metals. When that mixture percolates through the soil, the chemical pulls heavy metals loose. The team members then collected this toxic brew and ran it through an electrochemical filter that captured the heavy metals out of the water. In this way they cleansed the soil of heavy metals and recycled the water and chemical mixture to percolate through more contaminated ground.
Credits: Stanford University