Wednesday, December 27, 2017

"Panning for silver in laundry wastewater"

From ScienceDaily:
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 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 silver nanoparticles can be toxic to many aquatic organisms and can impact the effectiveness of bacterial processing in wastewater treatment plants. 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....MORE
Coincidentally there was a similar story making the rounds a few days ago that I'm pretty sure is apocryphal:
From, June 12, 2006:

Chinese Immigrants on America’s Western Frontier
A tiny fellow with a scarred cheek and eager eyes’John John’ the Chinese laundry man, was the laughingstock of Weaverville, California. For months during he had been washing the Anglo miners’ clothes and never had charged even a penny for his services.

The Anglos thought he was stupid, and intentionally took advantage of him. But a year later, according to prospector John Hoffman, who followed gold and silver trails through the Sierras for nearly three decades, one of the white miners came across John John wearing fine clothes in Sacramento. The Chinese laundry man had washed enough gold dust out of pants cuffs and shirttails to set himself up for life!....
I say probably apocryphal because I remembered seeing the story years ago,  had looked into it at the time and found no other record of John Hoffman or John John.
For what it's worth the place I had seen the story was the China Law Blog in the comments on a post a post dated Feb. 9, 2011:
Chinese Immigrants In America. Ummm.
The comment was almost word-for-word the same as the story.
It appears this is one of those quasi-periodic internet stories that circle around every 5 - 6 years.