A carbon nanotube sponge capable of soaking up fertilizers, pesticides, pharmaceuticals and other water contaminants is more than three times more efficient than previous water cleanup efforts, according to a study in Institute of Physics Publishing’s journal Nanotechnology.
The tests showed the carbon nanotube (CNT) sponges, doped with sulfur, also successfully absorbed oil, which means CNTs could be used in industrial accidents and oil spill cleanups, researchers say.
In the study, researchers from the University of Roma, University of Nantes and University of L’Aquila increased the CNT’s size by adding sulfur, producing sponges with an average length of 20 mm.
The addition of sulfur caused defects to form on the surface of the CNT sponges that enabled ferrocene — also added during the production process — to deposit iron into tiny capsules within the carbon shells. Iron allows the sponges to be magnetically controlled and driven without any direct contact, easing the existing problem of trying to control CNTs when added onto the water’s surface.
The researchers showed how the new CNT sponges could remove dichlorobenzene from water, absorbing a mass of the toxic organic solvent that was 3.5 times higher than previously achieved.
The study also showed the CNT sponges could absorb vegetable oil up to 150 times of its initial weight and absorb engine oil at a higher capacity compared with previous efforts.
Unprocessed raw cotton may be an ecologically friendly, lower cost solution to clean up oil spills, according to a report published last year in the American Chemical Society journal Industrial & Engineering Chemistry Research.