[Presto]

Okay, so in one year I'm going to graduate as Chemical Engineering. I'm really passionate about the environment, and I want to make it a better place, especially in my home city where nothing is done in order to be environmentally friendly. I want to dedicate my life to plastics and how to recycle them.

The question is: ¿Is it really possible to degrade PET? I mean, I know that generally it is reduced to tiny pieces and then melted.
Do you know a method that reduces PET in its monomers or other light organic molecules?

I have found this so far

• Scientists find fungus with an appetite for plastic in rubbish dump
• Watch this amazing machine transform plastic bags into fuel

I have to present a project before October end, and I want it to be this

[pgk]

There are both chemical methods for PET degradation (including hydrolysis or transesterification with small alcohols), as well as microbiologic ones.
So, hurry up because you don’t seem to have much time for literature search and composing a project proposal.

[Enthalpy]

¡Hola Presto!

To "possible to degrade", the answer is yes - but you supposedly implied "at reasonable cost" or even "economically", and then the answer is unclear. The difficulty is that the most common polymers (PE, PP, PET, PVC, ABS) are very cheap, in the order of 10⁰€/kg, their feedstock even more so, and this leaves very little money for recycling.

Recycling PET into PET (or PE into PE) is possible and done. It makes all the clothes made in Asia of unwoven plastic felt, like gloves and pullovers. Old bottles are sorted out, molten, extruded. With cheap manpower and nearly no transformation, it makes economic sense. If a chemical operation were necessary, it would need to be very cheap.

Fuel: made from polyolefines or old tyres rather than PET if I remember well. Again, the operation is very low-tech, essentially a pyrolysis. While the garbage disappears and less crude oil is used, I wonder if the operation makes our environment really cleaner. The reports don't tell what pollutants the pyrolysis leaves - it could well be a tar with much polycyclic aromatics, much worse than a plastic bottle.

One difficult limit to plastic recycling is that most consumers (...even educated) ignore the composition of a plastic item, so that PE is mixed with PET and even PVC in the garbage. Possibly the most needed progress presently would be a cheap and good machine that sorts out the plastics, either as garbage items or as chips. Which boils down to: identify the polymer quickly enough.

Among the degradation methods, you might consider sunlight, especially UV. But are the products more desirable than the polymers?