Turn orange peel into plastic? It's not as crazy as it sounds

"British scientists are pioneering a novel way of recycling that turns orange peel into plastic.

The technique relies on high-powered microwaves that can degrade the tough cellulose molecules of plant matter so that they release volatile gases that can be collected and distilled into a liquid product.

These valuable biodegradable chemicals can then be used in water purifiers, cleaning agents and plastics. Researchers behind the process say it is 90 per cent efficient and works not just on orange peel but almost any plant-based waste such as straw or coffee grounds.

James Clark, professor of green chemistry at the University of York, said he is building a small demonstrator facility to show the novel recycling scheme can be scaled up in order to suit industrial applications.

"It will be able to cope with tens of kilograms an hour. We believe it is the right scale to prove to people that this is a viable technology," Professor Clark said.

"You dice the peel and put it into a microwave field. You then focus the microwaves as you would with a domestic microwave oven but at higher power," he said.

"The microwaves activate the cellulose and that triggers the release of chemicals or further chemical reactions inside the orange peel," he told the British Science Festival at Bradford University.

Volatile chemicals are released in the process, including d-limonene, which is responsible for the distinctive smell of citrus fruit and is used in cosmetics, the cleaning industry and as a biological insecticide.

"As you produce the volatiles you strip them off continuously. It's a continuous process. You feed the peel into a microwave zone and have a pipe that takes off the volatile fractions as they are produced," he said

"The unique feature of our microwave is that we work at deliberately low temperatures. We never go above 200C. You can take the limonene off or you can turn limonene into other chemicals," he said. "It works really well with waste paper. It can take a big range of bio-waste material.""

Read more at The Independent