AEROGELS FROM ENVIRONMENTAL WASTES FOR NOVEL ENGINEERING APPLICATIONS

Associate Prof. Hai Minh Duong and Prof. Nhan Phan-Thien, National University of Singapore (NUS), Singapore

Recycling environmental waste can avoid many hazardous environmental scenarios and save resources. This new aerogel technology can recycle various environmental wastes to high-value engineering materials. Common paper, fabric, and plastic wastes are used to develop the lightest aerogel materials for novel applications such as oil spill cleaning, heat and sound insulation, winter garment materials, packaging, personal care, and medical products.

Using a cost-effective and green sol-gel technique with no toxic solvents and cross-linkers, recycled fibers from waste are converted into ultralight, porous, biodegradable, non-toxic aerogels. The method uses 70% less energy and results in reduced polluting emissions in the air and water. It is also faster, as the entire process takes only 8 hours to one day — 20 times faster than current commercial processes.

The developed aerogels are highly compressible; hence, storage and transportation costs are greatly reduced. The compressed aerogels can very quickly recover 97 % of their original size when placed in water, and the used aerogels can be recycled, eliminating waste. The hybrid aerogel pellets can be easy integrated into a clinical syringe to be used as a hemorrhage-control device. Each compressed aerogel pallet can expand in volume to 16 times its size in 4.5 seconds — three times faster than commercial hemorrhage devices — while retaining their structural integrity. The fast aerogel expansion also exerts high pressure to stop wound bleeding within five seconds.

The coated aerogel can absorb oil 99 times its dry weight and is four times as effective as commercial oil sorbents. They can be reused several times and can be recovered by squeezing out more than 99% of absorbed oil. At the end of their useful life, the used aerogel can be safely ground into fine particles and discarded.

With fire-retardant coating, the aerogels can withstand an ambient temperature of 600-620 ºC and prevent fire from spreading inside buildings.

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https://www.techbriefs.com/component/content/article/tb/pub/features/articles/33321