In 1950, global plastic production was about 2 million tons. It’s now about 400 million tons – an increase of nearly 20,000%.
As a material, it has seemingly limitless potential. Plastic is inexpensive to produce while being lightweight and sturdy. Its applications range from food and beverage packing to clothing and health care.
When a plastic item ends its useful life, it can take a very long time to decompose, up to 500 years in some cases. Even then, the plastic pieces don’t disappear entirely – instead, they break down into smaller and smaller pieces, eventually becoming microplastics that end up in the soil where we grow food, the water we drink and the air we breathe.
Research has linked these microplastics to health issues such as diabetes, heart disease and low male fertility.
For years, local governments and manufacturers have relied on recycling as the answer to keep plastic waste from accumulating. However, despite their efforts to sort and separate recyclables, most plastics still end up in landfills – or worse, in green spaces and waterways.
According to the U.S. Environmental Protection Agency, the overall recycling rate for plastics is 8.7%. About a third of milk jugs and plastic bottles are recycled – a higher rate than other types of plastic.
Because plastic is so commonly used, finding new ways to manage and recycle plastic waste is becoming ever more important. Plastic waste pyrolysis is one technology that could help address this issue.
This is a relatively new technique, so researchers still have only a limited knowledge of the pyrolysis process. As analytical chemists, we strive to understand the composition of complex mixtures, especially new creations from sources such as plastic waste pyrolysis.
What is plastic pyrolysis?
Plastic pyrolysis is a chemical process that involves chemically breaking down plastics into other molecules by heating the plastics to extremely high temperatures in the absence of oxygen.
Plastics are fed into the pyrolysis reactor, where they get hot and turn to oil. The oil moves to another vat where it’s boiled and distilled.
Alexander Kaplitz and Kevin A. Schug
Unlike traditional plastic recycling, pyrolysis theoretically isn’t limited to specific types of plastic. It could be made to accommodate many of them, although current technology is limited to a few types – polyethylene and polypropylene, used in food containers and bottles – at an industrial scale.
So, plastic pyrolysis could help handle the waste from consumer products such as plastic bags, bottles, milk jugs, packaging materials, wet wipes and even discarded children’s toys. Pyrolysis can also handle more complex plastic waste such as tires and discarded electronics, although solid waste handlers and recyclers avoid certain plastic types in pyrolysis, such as polyvinyl chloride – or PVC, which is found in pipes and roofing products – and…
