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Bioplastic made from CO2 and agricultural waste

Plastic consumption is a major problem, mostly because only a small part is recycled and a large part ends up in our oceans. However, we keep using it because it is so convenient and you can do so many things with it. One solution is to make bioplastic from renewable plant sources, because it has all the qualities of plastic and is in addition biodegradable. Scientists from Stanford University have discovered a new way to make bioplastic, from CO2 and inedible plant material.

The material is FDCA (furandicarboxylic acid), which is an ingredient for PEF (polyethylene furandicarboxylate). PEF is an alternative to the better-known PET (polyethylene terephthalate) that is made with petroleum. PEF has considerable advantages over PET, as it is better at sealing out oxygen, and FDCA can be produced from biomass.

Usually, bioplastic is made by converting fructose from corn syrup or other natural sugars into FDCA. The problem with this proces is that it takes a lot of energy and water to grow the plants. In addition, it competes with the food industry, because the plants are edible.

The Stanford scientists used inedible plant material to make FDCA. These are grasses and waste materials left over after harvest, so material that was produced anyway and would otherwise have been composted. Making FDCA with furfural, as the compound of inedible plant material is called, used to need hazardous chemicals that are expensive and energy intensive to make, which is why there was no inexpensive way to produce PEF.

The solution from the Stanford researchers came in the form of a combination of carbonate with CO2 and furoic acid, which is derived from furfural. This mixture is then heated to a temperature of 200 degrees Celsius (290 degrees Fahrenheit) until it forms a molten salt. After five hours, 89 per cent is converted to FDCA, which in turn can be turned into PEF. Products from PEF can be recycled or converted back to CO2 by incineration.

The CO2 required to make the plastic can be captured from fossil-fuel power plant emissions. Carbon turns out to be a great material, as it can be turned into concrete and even shoes as well, and now plastic. Let’s hope there will be more sustainable purposes for CO2 in the future, as well as with agricultural waste.

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