TALK about killing two birds with one stone. Every year we ditch millions of tonnes of chicken feathers, and pump climate-altering carbon dioxide into the air. But combine the two in the right way and you can make an otherwise-scarce fertiliser.
聯Put together chicken feathers and carbon dioxide and you can make an important fertiliser聰
More than 5 million tonnes of chicken feathers are produced globally every year. Most get thrown into landfill where they can sit for decades without breaking down.
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of the University of Science and Technology of China in Hefei, Anhui Province, and colleagues have found a use for them. Heat chicken feathers to 600 掳C for 3 hours in CO2 and two useful substances form ().
One is ammonium bicarbonate, a fertiliser and food additive. But even better, warm this substance to 60 掳C and it releases ammonia, an ingredient in urea, a superior fertiliser. Currently, 2 per cent of the world鈥檚 energy is consumed making ammonia, using the energy-intensive Haber process. Chen says that getting urea from chicken feathers instead could save some of this energy.
The second product is carbon micro-spheres, which Chen found can make a water-resistant coating. Alternatively, adding a catalyst turns them into carbon nanotubes, which have been used in everything from solar cells to biosensors.
鈥淪equestering carbon as ammonium bicarbonate or as urea is quite a smart idea,鈥� says of the US Department of Agriculture in Beltsville, Maryland.
Chen鈥檚 idea for chicken feathers has some competition. They can also be turned into plastic, or hydrogen fuel cells. Another group uses their complex structure to make composite materials like and . Breeders have even created featherless chickens, but these may suffer more and have not proved popular.
This article appeared in print under the headline 鈥淒ial up the heat to turn feathers into fertiliser鈥�
