For the first time, scientists observe a new way to move salt – and one day it could desalinate seawater.
It's official. Salt moves in mysterious ways.
For the first time, scientists from the University of Surrey have observed the effects of an electrical current created in a liquid by combining two kinds of salt.
Dr Richard Sear, from Surrey's School of Mathematics and Physics, said:
"This is a truly exciting discovery – the first time we've ever seen remote diffusiophoresis. Our research is at a very early stage, and we don't yet know how strong these currents could ultimately become. But the possibilities are tantalising."
When one salt is dissolved in a liquid, charged particles will drift through the liquid from the most concentrated areas to the least.
However, by adding a second type of salt, an electrical current can arise throughout the entire fluid almost instantly.
That current can move charged particles throughout the solution. This 'action-at-a-distance' effect is called non-local diffusiophoresis – and this is the first time scientists have ever seen it.
Scientists modelled how they expected several salts to behave in water. They then conducted experiments, dissolving various pairs of salts to find the pair with the biggest effect.
They knew that the local effects of the concentrations would cancel each other out. That meant any movement had to be explained by non-local diffusiophoresis.
The biggest effect was observed when dissolving sodium chloride with potassium acetate.
Dr Sear said:
"This process could one day be used to sort and separate substances within a liquid. Think how useful that could be for desalinating drinking water from the sea or separating solutions in industrial processes."
Source: https://www.surrey.ac.uk/