Plastic is a modern hazard and Plastic Pollution has a massive environmental impact. As of 2018, 380 million tonnes of plastic is being produced worldwide each year (source: Wikipedia). Since we all knew that plastic was bad a lot of effort was put in to get people to recycle plastics and single use plastics have been banned in a lot of places (In India they are banned as of 2019). However as per the recent report by NPR, recycling doesn’t keep plastic out of landfills as it is not economically viable at a large scale. It is simply cheaper to just bury the plastic than to clean it and recycle. Apparently this has been known for years now but the Big Oil companies kept it quite to protect their cash cow. So the hunt of what to do with the plastic continues and thanks to recent breakthroughs there just might be light at the end of this tunnel.
Apparently plastic has a high density of Hydrogen in it (something that I wasn’t aware of) and it is possible to extract this hydrogen to use as fuel for a greener future. The existing methods involve heating the plastic to ~750°C to decompose it into syngas (mixture of hydrogen and carbon monoxide) which are then separated in a second step. Unfortunately this process is energy intensive and difficult to make commercially viable.
Peter Edwards and his team at the University of Oxford decided to tackle this problem and found that if you broke the plastic into small pieces with a kitchen blender and mixed it with a catalyst of iron oxide and aluminium oxide, then microwaved it at 1000 watts then almost 97 percent of the gas in the plastic was released within seconds. To cherry on top is that the material left over after the process completed was almost exclusively carbon nanotubes which can be used in other projects and have vast applications.
The ubiquitous challenge of plastic waste has led to the modern descriptor plastisphere to represent the human-made plastic environment and ecosystem. Here we report a straightforward rapid method for the catalytic deconstruction of various plastic feedstocks into hydrogen and high-value carbons. We use microwaves together with abundant and inexpensive iron-based catalysts as microwave susceptors to initiate the catalytic deconstruction process. The one-step process typically takes 30–90 s to transform a sample of mechanically pulverized commercial plastic into hydrogen and (predominantly) multiwalled carbon nanotubes. A high hydrogen yield of 55.6 mmol g−1plastic is achieved, with over 97% of the theoretical mass of hydrogen being extracted from the deconstructed plastic. The approach is demonstrated on widely used, real-world plastic waste. This proof-of-concept advance highlights the potential of plastic waste itself as a valuable energy feedstock for the production of hydrogen and high-value carbon materials.
Their research was published in Nature Catalysis, DOI: 10.1038/s41929-020-00518-5 yesterday and is still in the early stages. But if this holds up at larger scale testing then it will allow us to significantly reduce the plastic waste that ends up in landfills and at the bottom of the ocean.
Source: New Scientist: Microwaving plastic waste can generate clean hydrogen
– Suramya