Studying Detergents to Solve Problem of Stray Silver Nanoparticles

As some clothing manufacturers have increasingly adopted the practice of incorporating silver nanoparticles into garments to fight odor-causing bacteria, science has been left to deal with what happens when that silver finds it way into waterways. As clothes containing silver are washed, some of the nanoparticles are washed away and enter wastewater. Since the particles can be toxic to some aquatic organisms and also impact the effectiveness of wastewater treatment plants, scientists are looking for ways to easily remove them. 

To help solve this problem, researchers are looking at the source: laundry. Recently a group of scientists has looked at how silver interacts with detergents, looking at individual detergent ingredients. Their finding was that the stray silver mainly exists as a positively charged ion, which means that those ions will interact with negatively charged ions in a detergent at different pH ranges.

The researchers used an ion-exchange resin to recover as much as 99 percent of the silver, depending on the pH and concentration of the competing ions. Unsurprisingly, however, the addition of different products such as bleach or water-softening agents negatively affected the efficiency of the resin.

To learn more about this work, see the published findings in ACS Sustainable Chemistry & Engineering.