Can Non-Recyclable Plastic Waste Be Made Environmentally Sustainable?

Luigi Campanella, Dipartimento Chimica, Sapienza, Università di Roma, Roma

Pino Suffritti, Dipartimento di Chimica e Farmacia, Università degli studi di Sassari

After death the fraction of living matter which is not biodegraded (shells, bones, corals, carbonaceous deposits) becomes environmentally sustainable. This is not the case for plastics so that these wastes should be either recycled or made environmentally inert and stored in secure repositories as a resource for future generations. Chemistry has offered different solutions to this problem, and each brings about advantages and disadvantages when compared to other options. One further possible route could consist in the enrichment of the plastics waste in carbon content (“carbonization”), in analogy with the production of charcoal from wood, but we hope to stimulate a debate about all the other possible routes among scientists and engineers in the involved fields.

There is a growing concern about the accumulation and dispersion of plastics waste. Plastics have become indispensable for human life and for industry, but their high chemical stability makes most of them not completely degradable when dispersed in soil, fresh and sea water, and in air, unless it was properly designed to be biodegradable.

Most plastics are obtained from fossil oil, up to about 10–12 % of the global production, according to an IEA report published in 2018.3 Even using the best plastic waste management practices, models predict that an important fraction of plastics waste (more than 22% in 2050) will accumulate, especially in surface water and oceans, reaching a mass of 500±100 Mt in 2050.

In oceans these wastes are able to create true plastic islands, that reached in 2018 an overall surface of 1.6·106 km2, corresponding to about 6 times the surface of France, in the Pacific Ocean only. Plastics waste degradation is accelerated by irradiation from the UV component of sunlight and by some mechanical wearing, with the continuous production of smaller and smaller debris, maintaining a substantial chemical integrity.

Energy recovery as heat, steam, or electricity by burning plastics wastes, that in 2016 represented the fate of as much as 40% of plastics waste, is strongly discouraged because of the production of greenhouse gases and pollutants.

As it will be better detailed below, different strategies have been proposed for reusing and recycling plastics waste, but its large fraction that accumulates in landfills and, what is much more dismaying, in surface waters and oceans, is generally not adequately considered. Although we are not pure specialists in the field, general common sense considerations led us to give our little contribution to drive the attention of the scientific community of chemists to this important problem in order to be allowed to say “I do my part of the job”.


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