Nanotube sponge promises improved pollution mop-up

Chinese scientists have developed a sponge made from carbon nanotubes that can absorb 180 times its own weight in organic pollutants.

The material, which could be used to clean up oil spills, is expected to perform nine times better than current materials, and can be reused simply after being squeezed.

The sponge, developed by professors Anyuan Cao of Peking University and Dehai Wu of Tsinghua University, is made from carbon nanotubes - microscopic-scale tubes that have been found to have numerous applications in electronic, medical and engineering technologies.

The tubes are particularly suited to mopping up oil spills because of their large surface area, and because they naturally repel water, which means that they soak up oil or other pollutants, while leaving water behind.

The scientists, whose research was published in the Advanced Materials journal, say that the sponge will absorb 143 times its own weight in diesel oil, and 175 times its own weight in ethylene glycol.

They added that a single pellet of the material can quickly absorb a spreading diesel oil film with an area up to 800 times its own size, even if placed at the edge of the spill.

The researchers also envisage the sponges being deployed as filters, membranes, or absorbants to remove bacteria or contaminants from liquids or gases during industrial or manufacturing processes. Other potential applications include noise-absorption layers in houses, and impact energy absorbers.