Plastic waste has brought destructive impacts to our environment. It causes floods by clogging drains, shortens animal lifespans when consumed, causes respiratory problems when burned, and contaminates water bodies when dumped into canals and oceans. In 2016 alone, the world generated 242 million tons of plastic waste. This waste primarily came from three regions: 57 million tons from East Asia and the Pacific, 45 million tons from Europe and Central Asia, and 35 million tons from North America.
If the present trend in plastic waste continues, studies revealed that there will be 12 million tons of plastic in landfills by 2050. That figure is about 35,000 times as heavy as the Empire State Building. Now, researchers are studyingeffective ways to recycle plastic waste produced by our planet.
Recycling Plastic Wastes
Plastic manufacturing has rapidly accelerated, doubling roughly every 15 years. It has outpaced nearly every other man-made material. A 2019 study published in the journal Science Advances revealed that of the 8.3 billion metric tons that have been produced, 6.3 billion metric tons have become plastic waste. Of that, only 9% has been recycled. About 79% was accumulated in landfills or located in the natural environment as litter.
Jenna Jambeck, a University of Georgia environmental engineer who specializes in studying plastic waste in the oceans, said that gaining control of plastic waste calls for a comprehensive, global approach that involves rethinking plastic chemistry, product design, recycling strategies, and consumer use. Countries must keep with their recycling strategies. According to National Geographic, an American pay television network and flagship channel that is owned by National Geographic Partners, the US ranks behind Europe (30%) and China (25%) in recycling.
“We as a society need to consider whether it’s worth trading off some convenience for a clean, healthy environment. For some products that are very problematic in the environment, maybe we think about using different materials. Or phasing them out,” Roland Geyer, the study’s lead author, said.
The vast majority of plastic waste is disposed of in landfills or littered in the natural environment while less than 10% of plastics are recycled due to several reasons. This includes inexpensive landfill space, low cost of feedstocks (monomers) derived from oil, and the fact some plastics like poly(vinyl chloride), low-density polyethylene, polypropylene, and polystyrene have chemical properties that make them difficult to recycle. Fortunately, many researchers are finding ways to take plastics apart.
According to C&EN, the world's most comprehensive and authoritative news source about chemistry and related fields, some methods that companies are using to recycle plastic waste involved returning them to their monomeric form, hoping that the reclaimed building blocks might replace fossil fuels as the feedstock for new materials. Other processes yield fuels or additives for other products. A huge challenge that many companies encounter when recycling is that not all plastics are equal. Polyethylene polymers (PET) and high-density polyethylene, for instance, are the most commonly recycled plastics in the US. This is because they can be shredded, cleaned, and remade into new bottles or lower-quality materials like carpet fiber.
While polystyrene waste can be processed and reused to make new products just like polyethylene plastics, companies hesitate to recycle due to fear of contamination. This material is usually used in food packaging, packing peanuts, disposable cutlery, and more which are likely to be dirty, adding to the cost of processing them for recycling. Nina Bellucci Butler, CEO of the consulting firm More Recycling, said that there are a lot of inefficiencies in the marketplace that prevent building an adequate recycling infrastructure.
“Even those companies that make major strides to reduce environmental impact don’t realize the reward or competitive advantage because not all claims of recycled content or recyclability have adequate oversight or transparency. Also, there is a failure to incorporate the environmental cost and benefit in using virgin materials versus recycled or the full environmental impact of landfilling our resources,” Butler said.
Chemical Recycling Might Be the Solution
Currently, mechanical recycling is the main method for recycling plastics. However, it has limitations. The plastic undergoes a process called downcycling which allows waste plastics to melt and form into new products, which are often of lower quality than the original products. These downcycled plastics, unfortunately, eventually become non-recyclable and end up in landfills. Many researchers think that chemical recycling is a perfect alternative to this.
Chemical recycling turns plastic waste into useful chemicals, some of which could be remade into new plastics. According to The Conversation, a network of not-for-profit media outlets that publish news stories written by academics and researchers, the method breaks the plastic down to the molecular level, making available “platform molecules” that can then be used to make other materials. Experts believe that chemical recycling could address some of the mechanical recycling’s shortcomings because it is more tolerant of contamination.
At the same time, the method yields polymers that are identical to the originals, eliminating downcycling. Extracting more value from waste plastics this way could provide the industry with the incentives and money it needs, perhaps creating a virtuous cycle. Chemical recycling could compliment mechanical recycling, especially for problem materials in physical recycling such as thin films and microplastics.
Chemical recycling can also change the way companies disregard polystyrene waste in recycling. “There was no end market for polystyrene. It was just benches and picture frames or things like that. Now we are closing the loop in a truly circular economy. We will be taking the styrene and producing virgin material that will go into any application: food, industrial, everything,” Ricardo Cuetos, Agilyx’s vice president of standard products, said.
Currently, many companies are eager to try chemical recycling. But, several challenges hinder them from doing so. Experts said that they need to build big, expensive plants and aggregate a lot of plastic waste. Beyond waste reductio, this method also has environmental benefits. Marco J. Castaldi, director of the Earth Engineering Center at the City College of New York, said that chemical recycling is much better than mechanical recycling in terms of greenhouse gas emissions efficiency because of the extra steps and heat involved in the process.