New “super sponge” soaks up water pollution in record time

Posted 31 March 2017

SpongeA new invention dubbed the ‘Super Sponge’ has been shown to remove mercury pollution from water in less than five seconds. 

Researchers from the University of Minnesota College of Food, Agriculture and Natural Sciences in the US have used nanotechnology to turn a regular sponge into a mercury-adsorbing material.

“A low-cost nanocomposite sponge prepared by growing selenium nanomaterials on the surface and throughout the bulk of a polyurethane sponge exhibits a record-breaking mercury ion removal rate, regardless of the pH,” the inventors wrote in a recent report

“The exposure of aqueous solutions to the sponge for a few seconds results in clean water with undetectable mercury levels. 

“Such performance is far below the acceptable limits in drinking water, industrial effluents and the most stringent surface water quality standards.”

Australian Water Quality Guidelines for Fresh and Marine Waters recommend a maximum 0.0001mg of mercury per litre.

The experiments showed the sponge had the additional benefits of not retaining water nutrients, it could significantly reduce the concentration of other heavy metal pollutants, and kill fungal and bacterial microbes.

The sponge could also be disposed of easily because it converted the contaminants into a complex that was not toxic, said the researchers. 

This could have applications in Australia, which is a comparatively big emitter of mercury globally. An estimated 18 tonnes of mercury is released into the air, land or water every year – double the global per-capita average. 

The National Pollutant Inventory shows that in 2014/15 the water industry (covering water supply, sewerage and drainage services) was responsible for 11,000kg of mercury emissions.

Human exposure to high levels of any types of mercury can permanently damage the brain, kidneys and developing foetuses.

And within the environment mercury (and its compounds) have high acute and chronic toxicity on aquatic life.