Recycling of plastic gets a boost

SYDNEY - Although plastic is a strong, cheap and hygienic material, its durability presents major problems when it comes to the environment.

Since plastic does not decompose when buried and casts off toxic smoke when burned, the global community has been struggling to find an effective way to recycle and reuse it.

Often a labor-intensive and time-consuming process, sorting through different types of plastic materials at recycling facilities can be extremely difficult.

But Licella, an Australian company, may have found a viable way.

"So the process works by taking heat and cutting the plastic into small pieces," said University of Sydney Professor Thomas Maschmeyer, who created the groundbreaking solution along with CEO Len Humphreys.

"The plastic goes from a solid to a wax, to a liquid, to a gas, and that process is called pyrolysis," he said.

Researchers have been looking into pyrolysis for a number of years as a way to solve the plastic crisis.

But success eluded them because the process gives rise to an unstable oil with a very low liquid yield that's mostly unusable.

By employing a new technique involving something scientists call "supercritical water", Maschmeyer and the team at Licella have managed to make it work.

Most people know water in the form of a solid, liquid or gas. Gas can become so compressed that it acts like a liquid at a certain temperature and pressure, which is a state called supercritical.

"So what happens is, the water suddenly changes from steam into a solvent that dissolves things ... and we're able to activate the hydrogen in the water and it then reacts with the decomposing plastic and then we add (more) hydrogen to the decomposing plastic to stabilize it," Maschmeyer said.

As a result, the liquid yields are between 80 and 90 percent, making the process extremely viable economically.

The finished product can then be turned into new plastics, diesel gas oils, industrial waxes and even road bitumen.

Maschmeyer said the company, already with a demonstration plant in Sydney, is now set to launch its first commercial facility in Britain next year.

Xinhua