Environment

New technique uses steam to make smelly plastics recyclable

New technique uses steam to ma...
It is hoped that the technique could reduce the amount of otherwise-recyclable plastic that ends up in landfills
It is hoped that the technique could reduce the amount of otherwise-recyclable plastic that ends up in landfills
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It is hoped that the technique could reduce the amount of otherwise-recyclable plastic that ends up in landfills
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It is hoped that the technique could reduce the amount of otherwise-recyclable plastic that ends up in landfills

Although chemicals, foods and other odorous substances are often sold in recyclable plastic containers, sometimes the smells absorbed by the plastic make it unsuitable for recycling. A new process, however, is claimed to get the stink out.

Developed by Prof. Andrés Fullana and researcher Andrea Cabanes, from Spain's University of Alicante, the technique reportedly removes volatile organic compounds (VOCs) that are emitted by a plastic container's contents and absorbed by its polymer matrix. According to the researchers, such a deodorizing process is currently impossible via conventional washing and recycling methods.

The procedure begins with used plastic containers being sorted, separated and pre-conditioned, after which they're crushed into small particles, chemically-washed with a special soap, rinsed and then dried. It's in the final "steam distillation" step that the actual odor-removal takes place.

Also known as "steam stripping," steam distillation basically involves passing steam through a material, within a column. As that steam rises, it carries VOCs that were in the material with it. When the steam subsequently condenses within a collector flask, the resulting VOC-laden liquid water can be separated and disposed of. That said, the process can also be used to obtain useful products, such as essential oils that are distilled from plant leaves.

The U Alicante technique has recently been patented, with five companies now expressing interest in commercializing the technology.

"There is a need to recycle in an efficient and environmentally-friendly way [this] plastic waste for later use as raw material, as well as to reduce its presence in landfills, reduce production costs in the industries of the sector, and to increase the added value of the product," says Cabanes.

Source: University of Alicante

2 comments
riczero-b
If you used the resultant steam for making coke-oven or producer gas it might enhance the resultant heat value. And it might give a warning odour to the CO rich fuel gas.
christopher
Waste of time - the plastics-recycling industry is 99% scam - almost all of it goes to landfill, after a long line of greedy middlemen have collected "recycle" taxes, levies, and grants from governments (who either don't care or are in on the scam) and willing consumers (who are allergic to paying attention to what's really going on). And that's not even starting on the biggest problem: in total-cost terms, it is always cheaper to buy new plastic, than try to recycle old stuff.