Novel solvents remove nanoplastics from water
As tiny nanoplastic particles continue to accumulate in the world’s waterways, the challenge remains to develop a cost-effective solution to remove them while leaving behind clean water. Now, researchers at the University of Missouri have developed a liquid-based solution that removes more than 98% of these microscopic plastic particles from water, which they described in the journal ACS Applied Engineering Materials.
“Nanoplastics can disrupt aquatic ecosystems and enter the food chain, posing a risk to both wildlife and humans,” said Piyuni Ishtaweera, who led the study while pursuing her PhD in nano and materials chemistry.
“We are developing better methods to remove pollutants like nanoplastics from the water.”
The team’s innovative method uses water-repellent solvents made from natural ingredients. Initially, the solvent stays on the water’s surface, just like oil floats on water. Once it is mixed with water and separated again, the solvent floats back to the surface, carrying the nanoplastic particles with it in its molecular structure.
“These solvents are made of safe, non-toxic ingredients and their ability to repel water prevents further contamination of water sources, making them a highly sustainable solution,” Ishtaweera said. The new method is also effective in both fresh and salt water, she added.
The Missouri team tested polystyrene-based nanoplastics in five different sizes, surpassing previous studies that focused primarily on a single size of plastic particle. The researchers simply removed the nanoplastic-laden solvent with a pipette, leaving behind clean, plastic-free water. However, future studies will work to scale the entire process so that it can be applied to larger bodies of water, such as lakes and eventually oceans.
“Our strategy uses a small amount of a designer solvent to absorb plastic particles from a large volume of water,” said Associate Professor Gary Baker, corresponding author of the study. “Currently, the capacity of these solvents is not well understood. In future work, we aim to determine the maximum capacity of the solvent. In addition, we will explore methods to recycle the solvents so that they can be reused multiple times if required.”
The breakthrough not only provides a practical solution to the pressing problem of nanoplastic pollution, but also paves the way for further research and development in advanced water treatment technologies. Ishtaweera concluded that “the development of effective removal methods will promote innovation in filter technology, provide insights into the behavior of nanomaterials, and support the development of sound environmental policy.”
