A liquid solvent-based solution offers a simple, effective means to extract nanoplastics present in potable water supplies. The process developed by University of Missouri researchers eliminates more than 98% of these human health-endangering microscopic plastic particles from water.

Hydrophobic deep eutectic solvents (HDESs) derived from nontoxic tetrabutylammonium bromide decanoic acid or tetraoctylammonium bromide decanoic acid initially float on the surface of water. When mixed with the water, the solvents attract nanoplastic particles and return them to the surface for collection. As they are water-repellent, the solvents are also easily removed along with the pollutant particles.

The solvent-based technology was evaluated in the laboratory with different sizes of polystyrene-based nanoplastics, a common type of plastic used in the making of Styrofoam cups. The results reported in ACS Applied Engineering Materials showed that this approach outperformed previous efforts that focused on just a single size of plastic particles, with nearly complete removal of nanoplastic sizes of 100 nm to 1,000 nm.

The treatment, which is effective in saltwater as well as in freshwater, will next be scaled up for application to larger bodies of water such as lakes and, eventually, oceans.