The world’s first biodegradable cellulose-based aerogel made from paper-waste that features an exceptional ability to absorb oil has been developed by Singaporean researchers.
The material can absorb up to four times as much oil as the best existing commercial sorbents. This, combined with its non-toxic and biodegradable nature, makes the material an ideal candidate for oil spill cleaning. Capable of absorbing up to 90 times its dried weight, the novel aerogel can be squeezed and up to 99 per cent of the absorbed oil recovered.
“Sorption has been considered one of the most effective ways to clean oil spills,” said Assistant Professor Duong Hai Minh from the Department of Mechanical Engineering at the National University of Singapore, who led the research.
“Polypropylene (PP)-based absorbents are widely used for oil absorption, but they are non-biodegradable and their absorption capabilities are both low and slow. Our novel cellulose aerogels therefore serve as an attractive alternative to current methods of oil spill cleaning, which has a potential market size of $143.5bn.”
The aerogel, coated with Trimethoxy-methylsilane, is water repellent and therefore absorbs only oil.
In addition to its environmentally friendly nature, the aerogel has been manufactured using an energy-saving method.
“Our fabrication process uses 70 per cent less energy, produces fewer polluting emissions into the air and water, as well as using less dioxins in the chlorine bleaching process,” Duong said. “It is also faster – the entire process only takes three days.”
The team believes that in addition to its oil-absorbing properties, the paper-based aerogel can find applications in many other sectors - for example, as an insulation material in the built environment or as a biodegradable packaging material, e.g. a replacement for plastic-based bubble wrap.
Further modifications can turn the aerogel into a smart coating material that can be used for drug deliveries or to stop bleeding. This is achieved by first infusing the aerogel with a solution of metallic nanoparticles. The cellulose aerogels are then hammered flat to remove most of the air, resulting in a magnetic thin film that has a weight capacity of over 28 tonnes per square centimetre.
A small piece of this flat aerogel can be inserted into a wound, where it expands like a sponge, stopping the bleeding in less than 20 seconds.
The team has filed a patent for their invention in the USA, China, India and Southeast Asia.