Plastic has been a revolutionary material over the past century, with an uncountable number of uses and an incredibly low price to boot. Unfortunately, this low cost has led to its use in many places where other materials might be better suited, and when this huge amount of material breaks down in the environment it can be incredibly persistent and harmful. This has led to many attempts to recycle it, and one of the more promising efforts recently came out of a lab at Northwestern University.
Plastics exist as polymers, long chains of monomers that have been joined together chemically. The holy grail of plastic recycling would be to convert the polymers back to monomers and then use them to re-make the plastics from scratch. This method uses a catalyst to break down polyethylene terephthalate (PET), one of the more common plastics. Once broken down, the PET is exposed to moist air which converts it into its constituent monomers which can then be used to make more PET for other uses.
Of course, the other thing that any “holy grail” of plastic recycling needs is to actually be cheaper and easier than making new plastic from crude oil, and since this method is still confined to the lab it remains to be seen if it will one day achieve this milestone as well. In the meantime, PET can also be recycled fairly easily by anyone who happens to have a 3D printer around.
The biggest challenge in recycling plastics in this manner is that the catalysts are somewhat selective or fouled by chemicals other than the intended plastic, so the feedstock needs to be clean and devoid of other materials like paper labels and glue, or bits of leftover products that were stored in the plastic.
So, a considerable amount of energy and water are needed to wash the plastic before recycling, although this does not remove contaminants entirely. Additives are also an issue. Then there’s the inconvenience for the consumers to separate different plastics at the point of collection. Some people just don’t care, and the different kinds of plastic get mixed in the waste stream anyways. The same problems persist throughout the waste handling process – it’s very difficult or impossible to separate one piece of plastic from another according to chemical composition through any sort of mechanical material handling process.
Publications like this focus on recycling PET bottles since they’re the lowest hanging fruit of the plastics recycling field. They’re well separated and made easy to recycle, whereas general mixed plastics aren’t.
Depending on the quality of Plastic, the most easiest way to reuse it is to utilize it in the construction industry for building houses for the homeless under the UN. It will protect the environment, and support sustainability.
Another viable way is to use it for energy generation purpose (for non-halogenated plastics)
That is true, however, using plastics by “downcycling” them in buildings and construction doesn’t make the problem go away. The lifecycle of a building is far longer compared to plastic containers and other items of use, so there’s far more supply than there is demand and the problem re-surfaces when the demand is satisfied. Ultimately, the plastic is still there, only more mixed up with other materials and even harder to separate, and then ends up in the environment when the building is inevitably torn down.
On another note, dumping waste on poorer countries under the guise of “relief” is both patronizing and damaging to the economies of those countries, because it displaces domestic production and industries in the target country. You know the old saying, “give a man a fish and he’ll eat for a day.”
The main problem is that plastics are very often the optimal material for an application.
They have a bad reputation, but they combine desirable properties (e.g. light weight, impact resistance, chemical resistance, good surface properties, ease of processing) with reasonably low cost. Of course we should try to reduce our plastic usage, but not religiously so–many alternatives are worse overall.
Of course, plastic waste is a problem. Plastic recycling needs to be developed and we need incentives to recycle plastic as much as possible, especially post-consumer plastic. However, the more I research this, the more I come to the conclusion that burning plastic as fuel is a viable method. We burn a large amount of fossil fuels just for process heat. Non-halogenated plastics can be burnt cleanly, are readily available and have a high energy density. So instead of burning fossil fuels, I’d rather we turn them into plastics first, then use these plastics for whatever good purpose we have, then collect them properly and then burn them for energy. Putting plastics somewhere to (never) rot and pollute the environment is clearly the wrong approach, so we could as well use the stored energy for heating.
Can be recycled as building material!!!
Most stuff can be recycled as “building material” if you include use as filler in concrete or the like – all that does is shift the problem 50 years down the line and potentially make the next recycling job even harder.
Also, with respect to any kind of recycling, not enough people think about the fact that “edible” does not need to mean “nutritious” or even “food”.
Something I don’t think has been explored enough for waste management.
https://hackaday.com/2023/11/15/diesel-station-wagon-runs-on-plastic/
This is the best way to recycle plastic. Dirty? Mixed varieties? Who cares?! It all burns the same.
Plants will take the emitted CO2 and turn it into food, wood, shade, clean air, and numerous other useful things. It’s a great, well-designed system.
Too bad we have too much CO2 production already.
The advantages of plastics are so great that due to our own cognitive dissonance we will never address their downsides until it is too late. A material which can theoretically be molded into any possible shape, can be hygenic, weighs less than most other common materials (so helps lower transportation costs). We have no immediate incentive to move away from its use, we always have long term incentive to deal with it.
We won’t completely eliminate plastics from environment, but we recycle them.. Traditional recycling methods were not very effective. Transforming plastic waste as an alternative resource, instead of exploiting natural resource is definitely make sense