Panning for silver in laundry wastewater

December 20, 2017, American Chemical Society

Silver nanoparticles are being used in clothing for their anti-odor abilities but some of this silver comes off when the clothes are laundered. The wastewater from this process could end up in the environment, possibly harming aquatic life, so researchers have attempted to recover the silver. Now, one group reports in ACS Sustainable Chemistry & Engineering that detergent chemistry plays a significant role in how much of this silver can be removed from laundry wastewater.

Some clothing manufacturers incorporate silver nanoparticles into their products because these tiny bits of metal can kill odor-causing bacteria. But researchers have found that some of that silver is washed away as the garments are laundered. These can be toxic to many aquatic organisms and can impact the effectiveness of bacterial processing in . But recovering the nanomaterial from laundry water isn't an easy process because of low concentrations of silver in the water, high concentrations of competing ions and an uncertainty as to which exact forms of silver are present. Previous research by Sukalyan Sengupta and Tabish Nawaz showed that ion-exchange technology is highly selective for silver, but this study did not examine the role of detergent chemistry, which could interfere with this method. So that's what they wanted to examine in the current report.

The researchers analyzed how silver interacts with individual detergent ingredients. The team found that silver mainly exists as a positively charged ion, and this form will interact with several detergent compounds under certain conditions. 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, depending on the pH and concentration of the competing ions. The resin was then tested with components and reused over five cycles, and it maintained the ability to remove . But the addition of products, such as bleaching and water-softening agents, negatively impacted the efficiency of the resin.

Explore further: The impact of anti-odor clothing on the environment

More information: Tabish Nawaz et al. Silver Recovery from Laundry Washwater: The Role of Detergent Chemistry, ACS Sustainable Chemistry & Engineering (2017). DOI: 10.1021/acssuschemeng.7b02933

Related Stories

The impact of anti-odor clothing on the environment

March 30, 2016

Anti-odor athletic clothes containing silver nanoparticles have gained a foothold among exercise buffs, but questions have arisen over how safe and effective they are. Now scientists report in ACS' journal Environmental Science ...

Wiping out bacteria with nanoparticle-cotton fibers

July 4, 2017

Silver has been used as an antimicrobial agent for more than 100 years. Today, silver in the form of nanoparticles is incorporated in such products as plastic food containers, medical materials, and clothing. In textiles, ...

Too much nanotechnology may be killing beneficial bacteria

April 29, 2008

Too much of a good thing could be harmful to the environment. For years, scientists have known about silver’s ability to kill harmful bacteria and, recently, have used this knowledge to create consumer products containing ...

Recommended for you

New technology for diagnosing immunity to Ebola

January 15, 2018

A promising new approach to detect immunity to Ebola virus infection has been developed by researchers from i-sense in a collaboration between UCL and Imperial College London.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

MR166
not rated yet Dec 20, 2017
Oh wonderful, is this the new asbestos/lead/mecury? Sorry you have to have your house tested for cancer causing silver nano-particles before you can sell it.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.