Genoa, 23 July 2012 – After industrial or naval accidents, the health of the ecosystem of seas and rivers can be compromised, due to the spilling of oily substances, such as petroleum, which are very difficult for man to remove. The researchers at the Istituto Italiano di Tecnologia (IIT) created a sponge capable of absorbing oils, separating them from water, which can be maneuvered through magnetic fields, providing a new solution to the problem of water pollution.
The new material is described in the article "Magnetically driven floating foams for the removal of oil contaminants from water", published by the prestigious journal of the American Chemical Society ACSNano, and has been ideated by the Smart Materials group coordinated by Dr. Athanassia Athanassiou, at the Center for Biomolecular Nanotechnologies (CBN) of the Istituto Italiano di Tecnologia at the Università del Salento in Lecce.
The new sponge is made with an low cost material modified by nanotechnological processes easy to transfer to industrial scale. The primary material is polyurethane foam, an economic material normally used in packaging and thermal insulation, which is processed with nanoparticles of iron oxide and polytetrafluoroethylene (known as Teflon), thus acquiring magnetic, superhydrophobic and superoleophilic properties.
The processing of polyurethane takes place in two main phases. In the first phase the foam is dampened with a solution containing colloidal magnetic nanoparticles of iron oxide. The second step consists in attaching the particles of polytetrafluoroethylene on the surface of the polymeric foam. This process makes the material capable of absorbing a quantity of oily substance up to thirteen times its own weight.
«The order with which the two steps of the process are done is important to define the surface properties of the sponge. – explains Dr. Despina Fragouli, team leader at IIT and first responsible of the research – Only if Teflon is rubbed after the insertion of the magnetic nanoparticles, the surface of polyurethane becomes highly super-hydrophobic and self-cleaning. The result is a light and floating sponge, capable of absorbing oily substances and of totally repelling the water, which, thanks to its magnetic properties, can be driven using appropriate magnetic fields onto polluted areas».
«80% of the nanoparticles introduced in the foam can be recovered and reused after the process. – comments Dr. Athanassia Athanassiou, coordinator of the Smart Materials team of IIT – Thus, our new sponge is an economic, innovative, intelligent and ecological material, being capable of solving important problems such as environmental pollution.»