In addition to the many negative effects that plastic waste brings, we can now see the positive side of them, talking about a really unexpected use.
Chemists have managed to turn plastic bags and other packaging into a clean source of hydrogen, using microwaves.
At the moment, plastic waste can be converted to hydrogen using other methods and commercial facilities for plastic processing are already being developed. However, a new approach promises to streamline the process, making it faster and lowering energy consumption.
How does plastic become hydrogen?
To confront the grim reality of plastic waste, Peter Edwards of Oxford University and his colleagues looked for a way to improve upcycle processes.
Because the density of hydrogen in plastic bags is about 14% by weight, plastic provides a possible new source for countries aiming for cleanly produced hydrogen to combat climate change.
Most existing approaches first involve the use of very high temperatures above 750 ° C to decompose the plastic into syngas – a mixture of hydrogen and carbon monoxide. Subsequently, it proceeds to the second step, in which the hydrogen is separated from the CO.
The methodological difference involved in Edwards’ approach saves time and effort in this process.
Instead, Edwards and his team broke the plastic into small pieces with a kitchen blender and mixed it with an iron oxide and aluminum oxide catalyst.
Using a 1000-watt microwave generator, the catalyst created hot spots in the plastic and removed the hydrogen – recovering 97% of the plastic gas in just a few seconds.
The solid material residues were almost exclusively carbon nanotubes.
The one-step approach has the advantage of heating only the catalyst, not all the plastic, resulting in a lower energy use, as the plastic does not absorb the microwave.
The results show “a potentially attractive solution for plastic waste,” says Edwards.
Although the experiment was done only on a small scale, with about 300 grams of plastic for each test, larger experiments are already planned. This involves creating a solution with commercial or even industrial utility for the problem of plastic waste.