Source: Paperinkeräys

This pioneering work was achieved by a team led by Assistant Professor Duong Hai Minh from the Department of Mechanical Engineering.

- Traditional aerogels are mainly made of silica, which is not environmentally-friendly. In contrast, cellulose is low cost and makes up 75 to 85 per cent of recycled paper. Our team developed a simple, cost-effective and fast method of converting paper waste into aerogels. In addition to low thermal conductivity, these novel aerogels have several unique features, one of which is super high oil absorption capacity - it is up to four times higher than commercial sorbents available in the market. We are very excited about the potential applications of this new material, Assistant Professor Duong says according to a press release.

Putting paper waste to good use

The global production of paper is expected to increase to 500 million tonnes by 2020. The large amount of paper-related waste generated annually causes destruction of forestation and environmental pollution, and the enormous waste is also difficult to dispose. Recycling or converting paper waste into useful products, therefore, contributes towards environmental conservation.

Now the NUS team has done just that by developing an eco-friendly process to convert paper waste into aerogels.

- Our fabrication process uses 70 per cent less energy, produces fewer polluting emissions into the air and water, as well as uses less dioxins in the chlorine bleaching process. It is also faster – the entire process only takes three days.

New relief for oil spills?

The novel cellulose aerogels developed by the NUS team are claimed to be four times more effective than existing commercial oil sorbents. Coated with Trimethoxy-methylsilane (MTMS), the aerogels are water repellent and are capable of absorbing oil (excluding water) up to 90 times their dry weight, making them up to four times more effective than commercial oil sorbents. Furthermore, they can be squeezed to recover over 99 per cent of the crude oil absorbed.

- Sorption has been considered one of the most effective ways to clean oil spills. Polypropylene (PP)-based absorbents are widely used for oil absorption but they are non-biodegradable, and their absorption capabilities are both low and slow.

Super heat insulation materials

Another important application of the novel cellulose aerogels is to serve as insulation materials for buildings.

- The water repellent property of our novel aerogels allows them to be adaptable to both dry and rainy weather and their structure remains stable for about six months in tropical climate. Being extremely strong, they increase building strength. In addition, these aerogels are lightweight and slim, resulting in slimmer walls, thus increasing building space.

They could also signal a change in the packing industry replacing plastic-based packing materials such as the bubble wrap with biodegradable aerogel-based foam or advanced cellulose aerogel nanosheets, which are environmentally-friendly. Moreover, with high surface area and high porosity, the biodegradable aerogels could also be used as coating materials in drug delivery or as smart materials.

http://www.nus.edu.sg/