Two recent research studies have explored the complexity of mitigating the impacts of plastics on the environment – with results showing that many silver linings have a cloud.
Researchers at Virginia Tech have outlined a ‘highly efficient and resilient’ process of upcycling polystyrene into chemical compounds to extend its useful life.
Polystyrene is generally considered to be non-biodegradable, with estimates varying but converging on the degradation process taking hundreds of years. It is also one of the least recycled plastics, partly because of its significant air proportion and partly because of its use in holding food, meaning the plastic is contaminated.
In a paper published in the Proceedings of the National Academy of Sciences journal, researchers therefore explored the feasibility of giving these polymers a second chance. The resultant compounds included benzophenone, which is a substance used in lip balm and nail polish.
“Plastic waste represents one of the most urgent environmental challenges facing humankind,” the report abstract explained. “Upcycling has been proposed to solve the low profitability and high market sensitivity of known recycling methods.”
The report noted that existing upcycling methods ‘operate under energy-intense conditions’ and produce low-value results. This approach, however, ‘exploits high-value chemicals from polystyrene waste with high selectivity.’
Yet the results are far from perfect. Diphenylmethane, one of the compounds extracted, is considered in its GHS (Globally Harmonized System) classification as being ‘very toxic to aquatic life with long-lasting effects.’ As the publication Inverse suggests, prevention is much better than cure, but ‘for now, thinking up novel, efficient ways to recycle plastic can usher us toward a more sustainable future.’
A report published last month by McKinsey has argued that while plastics continue to be a cancer on the environment, the nearest alternatives almost always had an even worse impact.
The report, titled ‘Climate Impact of Plastics’ (pdf), looked at five sectors – packaging, building and construction, automotive, textiles, and consumer durables – and analysed 14 applications with non-plastic alternatives, such as metal or glass. The report noted that in some areas, such as food packaging, there are few alternatives. The sectors contribute an estimated 90% of all plastics used.
In 13 of the 14 cases, which focused exclusively on the United States, the plastics offered a lower total greenhouse gas contribution compared with non-plastic alternatives. A plastic grocery bag emitted 80% less emissions than a paper equivalent, while a plastic soft drink container was better than an aluminium equivalent to the tune of 50%. The single outlier, a steel industrial drum, saw an up tick of 30%.
How did the report come to these findings? Part of the reason was down to ‘indirect value-chain impacts’, such as in production and disposal, which can be considered ‘substantial.’ An example can be seen in hybrid vehicles which use plastic fuel tanks. The lighter plastic material, compared with steel, reduces the vehicle’s weight and improves fuel efficiency.
The report authors suggest that in areas such as Europe, where there is a closer push to a lower-carbon, more circular economy, the benefits of plastic diminish.
“Our objective is to contribute to the dialogue on material choice and broaden the available fact base for the evolving discussion around plastics,” the report authors noted. “We once again highlight that the benefits of plastics do not diminish the industry’s need to continue improving environmental performance, including meeting Net Zero targets, achieving significant improvements in recycling, and eliminating leakage for the environment.”
Ultimately, both studies offer findings that can point a way forward but still illustrate the enormousness of the situation.
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