Magnetic Soap that can Mop up Oil Spills

A team of chemists at the University of Bristol has developed a liquid soap that can be controlled by magnets. It's hoped that the controllable soap could be used to clean up oil spills at sea.

The soap is composed of iron-rich salts dissolved in water, which respond to a magnetic field when placed in solution. The crucial thing is that the soap could be removed from the water after an oil spill, calming concerns from environmentalists over the use of surfactants in clean-up operations.

The breakthrough -- detailed in German chemistry journal Angewandte Chemie -- is the world's first soap sensitive to a magnetic field. The team at the University of Bristol have previously worked on soaps that are sensitive to light, carbon dioxide or changes in pH, temperature and pressure.

Ionic liquid surfactants -- made up of mostly water with some heavy metals such as iron bound to halides such as bromine or chlorine -- have been suggested as potentially controllable by magnets for some time, but it's always been assumed that their metallic centres would be too isolated within the solution, preventing the long-range interactions required to be magnetically active.

The Bristol team -- led by Professor Julian Eastoe -- created their magnetic soap by dissolving iron in a range of inert surfactants composed of chloride and bromide ions -- very similar to those found in everyday mouthwash or fabric conditioner. This created soap particles with metallic centres. The soap was found to be able to overcome both gravity and the surface tension between water and oil in order to rise up through the organic solvent and reach the magnet, allowing it to be controlled.

..........................................................................................................................................................

More...

• LEDs Saving More Electricity than Solar can Produce
• Unclaimed Environmental Prizes

...........................................................................................................................................................

Magnetic soaps have a wide range of potential applications. Their ability to respond to external stimuli means that a range of properties -- such as their electrical conductivity and how easily they dissolve in water -- could be altered by turning a magnet on or off. Traditionally, these factors can only be controlled by adding an electrical charge to the soap or changing the pH, temperature, or pressure of the system.

They could also be easily removed from a system after being added -- ideal for environmental cleanups and water treatment. One of the problems with using soaps to remove oil from the sea after oil spills is that you might remove the oil, but you replace it with loads of soap -- which can also disrupt ecosystems. Furthermore, they could be helpful in scientific experiments which require precise control of liquid droplets.

Professor Julian Eastoe, University of Bristol, explained: "As most magnets are metals, from a purely scientific point of view these ionic liquid surfactants are highly unusual, making them a particularly interesting discovery."
He added, "while these exact liquids aren't yet ready to appear in any household product, proving that magnetic soaps can be developed means that future work can reproduce the same phenomenon in more commercially viable liquids for a range of applications from water treatment to industrial cleaning products."

Posted in: environment,magnetic soap,oil spills