Microwaving plastic waste is generating clean reusable hydrogen

Chemists have successfully converted plastic waste into a clean reusable source of hydrogen. Could this become a viable way of reversing the damage caused by plastic pollution?

A team of chemists at the University of Oxford have developed a potentially revolutionary way of repurposing plastic waste sustainably and quickly using microwaves.

Currently, everyday plastic waste takes around 1000 years to degrade naturally, but research leader Professor Edwards’ new method of converting bags, bottles, and general packaging into reusable hydrogen may provide a feasible way of slowly reducing the total amount left to decompose in waterways and landfill.

Plastic waste – in particular carrier bags – contains a hydrogen density of around 14% and scientists have previously suggested that we may be able get rid of existing plastic waste whilst simultaneously collecting cleanly produced hydrogen. This, in turn, could help decarbonise industries currently relying on fossil fuels. Two birds, one stone.

Edwards and his team have added serious credence to that prospect with a recent small-scale experiment. Taking samples of plastic waste weighing around 300 grams and breaking them down in a regular kitchen blender, they mixed the solution in a catalyst of iron and aluminium oxide and heated the contents in a microwave generator at 1000 watts.

The team were hoping that by microwaving the catalyst solution, and not the stubborn plastic directly, they could extract the hydrogen concealed in the plastic without using an abundance of energy to break it down directly – as plastic doesn’t absorb microwaves itself, unlike the catalyst. Their hunch was correct.

Previous attempts at stripping hydrogen from plastic had involved using thermal conversion chambers to pump out heats of up to 850°C to decompose plastic into a mixture of hydrogen and carbon monoxide called syngas. But as you can imagine, this method requires a ton of energy and serious financial backing to achieve on a single-use basis, with £130 million being the purported asking fee to build a handful of facilities across the UK.

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The results of the experiment at Oxford’s Department of Chemistry may just put such initiatives on hold though. In a promising turn of events, Edwards and his team were able to strip up to 97% of the hydrogen contained within the plastic test samples in a very short matter of time, meaning we may be onto a low-cost alternative to thermal conversion chambers with no CO2 burden.

In a statement from the University, Edward revealed that this new process could ‘open up an entirely new area of catalysis in terms of selectivity’. He declared, ‘This offers a potential route to the challenge of the plastic waste Armageddon, particularly in developing countries as one route to the hydrogen economy – effectively enabling them to leap-frog the sole use of fossil fuels.’

It’s encouraging to learn that potential solutions are being developed right now, and that people refuse to adopt an apathetic attitude towards solving the plastic pollution issue. The typical rhetoric when discussing waste management may be inherently negative, and granted, the numbers emerging from annual reports appear insurmountable, but we have to continue to change, to innovate, and to find ways of protecting the sanctity of the planet whilst we’re here.

Could it really be that the plastic waste plaguing our land and oceans could soon become valuable livestock for the production of clean hydrogen fuel? Wouldn’t that just be a doozy.

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