Nanosilver more durable than standard silver coatings, says Empa
Swiss research institute Empa has published the results of a study that shows textiles with nano-coatings release fewer particles into water than normal coatings.
“If it contains 'nano', it doesn't primarily leak 'nano', at least that's true for silver-coated textiles,” said 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. Nano-coated textiles release hardly any nano-particles compared with ordinary coatings, where different silver particles were found, it said.
Nano-coated silver textiles generally lose less silver during washing because less silver is incorporated into textile fabrics with nano-coatings.
“All silver textiles behave in a similar manner - regardless of whether they are nano-coated or conventionally-coated,” said Mr 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.
Silver reacts with the small quantities of sulphur in the air to form silver sulphide, and the same process takes place in the waste water treatment plant. The silver sulphide, which is insoluble, settles at the bottom of the sedimentation tank and is incinerated with the sewage sludge.
“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,” said Empa.
