Featured Research

from universities, journals, and other organizations

Silver in the washing machine: Nano-coatings release almost no nano-particles, experts say

Date:
June 30, 2014
Source:
Empa Swiss Federal Laboratories for Materials Science and Technology
Summary:
The antibacterial properties of silver-coated textiles are popular in the fields of sport and medicine. Scientists have now investigated how different silver coatings behave in the washing machine, and they have discovered something important: textiles with nano-coatings release fewer nano-particles into the washing water than those with normal coatings.

Graph of silver particles released in the washing machine.
Credit: Image courtesy of Empa Swiss Federal Laboratories for Materials Science and Technology

If it contains 'nano', it doesn't primarily leak 'nano': at least that's true for silver-coated textiles, explains Bernd Nowack of the Technology and Society division at Empa. During each wash cycle a certain amount of the silver coating is washed out of the textiles and ends up in the waste water. Empa analysed this water; it turned out that nano-coated textiles release hardly any nano-particles. That's quite the opposite to ordinary coatings, where a lot of different silver particles were found. Moreover, nano-coated silver textiles generally lose less silver during washing. This is because considerably less silver is incorporated into textile fabrics with nano-coating, and so it is released in smaller quantities for the antibacterial effect than is the case with ordinary coatings.

Related Articles


A surprising result that has a transformative effect on future analyses and on the treatment of silver textiles. All silver textiles behave in a similar manner -- regardless of whether they are nano-coated or conventionally-coated, says Nowack. This is why nano-textiles should not be subjected to stricter regulation than textiles with conventional silver-coatings, and this is relevant for current discussions concerning possible special regulations for nano-silver.

But what is the significance of silver particles in waste water? Exposed silver reacts with the (small quantities of) sulphur in the air to form silver sulphite, and the same process takes place in the waste water treatment plant. The silver sulphite, which is insoluble, settles at the bottom of the sedimentation tank and is subsequently incinerated with the sewage sludge. So hardly any of the silver from the waste water remains in the environment. Silver is harmless because it is relatively non-toxic for humans. Even if silver particles are released from the textile fabric as a result of strong sweating, they are not absorbed by healthy skin.

Which detergent for which coating?

Next, Nowack's team wants to investigate how silver textiles respond to various ordinary laundry detergents. Studies have shown that some active ingredients of laundry detergents can alter the form in which silver is present. For example, before washing researchers have detected silver ions, i.e. dissolved silver (a conventional form of silver) in textile fabrics, whereas after washing they detected elemental, i.e. metallic, nano-silver or other silver compounds, such as (insoluble) silver chloride.

So silver textiles ultimately contain a number of silver compounds that constantly change and undergo chemical transformations. And they don't just do that during washing, as Nowack stresses. "Even during the manufacturing and coating processes, external influences can have an effect on the composition of the silver particles in textiles, even before the customer has got the product hanging in their wardrobe at home."


Story Source:

The above story is based on materials provided by Empa Swiss Federal Laboratories for Materials Science and Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Denise M. Mitrano, Elisa Rimmele, Adrian Wichser, Rolf Erni, Murray Height, Bernd Nowack. Presence of Nanoparticles in Wash Water from Conventional Silver and Nano-silver Textiles. ACS Nano, 2014; 140626093542005 DOI: 10.1021/nn502228w

Cite This Page:

Empa Swiss Federal Laboratories for Materials Science and Technology. "Silver in the washing machine: Nano-coatings release almost no nano-particles, experts say." ScienceDaily. ScienceDaily, 30 June 2014. <www.sciencedaily.com/releases/2014/06/140630093350.htm>.
Empa Swiss Federal Laboratories for Materials Science and Technology. (2014, June 30). Silver in the washing machine: Nano-coatings release almost no nano-particles, experts say. ScienceDaily. Retrieved March 26, 2015 from www.sciencedaily.com/releases/2014/06/140630093350.htm
Empa Swiss Federal Laboratories for Materials Science and Technology. "Silver in the washing machine: Nano-coatings release almost no nano-particles, experts say." ScienceDaily. www.sciencedaily.com/releases/2014/06/140630093350.htm (accessed March 26, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, March 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Amazon Complains U.S. Is Too Slow To Regulate Drones

Amazon Complains U.S. Is Too Slow To Regulate Drones

Newsy (Mar. 25, 2015) Days after getting approval to test certain commercial drones, Amazon says the Federal Aviation Administration is dragging its feet on the matter. Video provided by Newsy
Powered by NewsLook.com
Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Reuters - Innovations Video Online (Mar. 25, 2015) European researchers say our smartphone use offers scientists an ideal testing ground for human brain plasticity. Dr Ako Ghosh&apos;s team discovered that the brains and thumbs of smartphone users interact differently from those who use old-fashioned handsets. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
China Wants to Export Its Steel Problem

China Wants to Export Its Steel Problem

Reuters - Business Video Online (Mar. 25, 2015) China is facing a crisis with a glut of steel and growing public anger over the pollution created by production. In a move to solve the problem, some steel mills are looking to relocate overseas. Jane Lanhee Lee reports. Video provided by Reuters
Powered by NewsLook.com
Robot Stays on Its Feet Despite Punishment

Robot Stays on Its Feet Despite Punishment

Reuters - Innovations Video Online (Mar. 24, 2015) Robotic engineers have modelled a two-legged robot to be fast and agile like an ostrich. The design is more efficient and stable than bipedal robots built to move like humans, according to its creators who abuse the poor machine to test its skills. Ben Gruber has more. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins