Laundry wastewater is usually considered an environmental threat; micro-plastics and detergents are being monitored for polluting water resources. However, scientists now claim that laundry wastewater can be also a source of silver. Silver nanoparticles are being used in clothing for their anti-odor abilities. Sometimes they come off when the clothes are laundered. Instead of dumping this silver in the environment, researchers have attempted to recover it, according to a paper published in ACS Sustainable Chemistry & Engineering.
The researchers analyzed how silver interacts with individual detergent ingredients. The team found that silver mainly exists as a positively charged ion, and interacts with detergent compounds. For example, the positively charged silver ion will interact with negatively charged ions in the detergent at different pH ranges. The group also used an ion-exchange resin, which recovered as much as about 99 percent of the silver. However, the actual amount depends on the pH and concentration of the competing ions. The resin was then tested with detergent components and reused over five cycles, and it maintained the ability to remove silver.
It is not clear whether the amount of silver represents a possible incentive for home consumers to take special care of wastewater. However the environmental effects if such a solution is supported can be significant.