© IPC PAS, Grzegorz Krzyżewski
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Plastic is everywhere, not just in our households. Plastic bags and bottles pollute the environment including the oceans. Just recently, a researcher discovered a plastic bag in the Mariana Trench at a depth of almost 11,000 meters. And tiny microplastic particles are in the air we breathe and the water we drink and in what we eat. According to the latest information, each of us – whether we like it or not – allegedly eats five grams of plastic every week. That’s the weight of a credit card. Recently, microplastic was even detected in the polar ice of the Arctic and Antarctic.

In the battle against plastic waste, scientists around the world have been searching for alternatives that are as light and resistant as conventional plastics, but biodegradable and eco-friendly. At the Institute of Physical Chemistry of the Polish Academy of Sciences, researchers led by Prof. Juan Carlos Colmenares have now succeeded in producing Hydroxymethylfurfural (HMF) out of waste from food production.

“We would like to be able to replace PET with something that would take several months or at most several years to degrade,” explains Prof. Colmenares. “Today’s petroleum plastics contain phthalates and other plasticizers – such as ‘mixtures’ of organic and even inorganic compounds – which are not degraded by bacteria or fungi. This is why they remain in forests and seas for so long. Plastics based on DFFs contain sugar furans, and what comes from nature, is more readily accepted by nature.”

System for the selective photocatalytic upgrading of cellulosic biomass © IPC PAS, Grzegorz Krzyżewski

Colmenares and his colleagues have already carried out tests with such polymers. “They decompose into sugar-like monomers. And many microorganisms love sugar. Even if you dump a bottle of this material in the forest, it disintegrates after just a few years at the latest. This is much faster than conventional polymers,” he explains. However, it is not the product itself that is new, but rather the production method. Previously, the production of bioplastics requires high temperatures (approx. 100 to 150 degrees Celsius) and complicated technology. As a result, bioplastics were ecologically better but far more expensive than plastic made from crude oil.

Thanks to newly developed nanorods made from manganese dioxide (MnO2), that act as catalysts which accelerate partial oxidation within the process, the plastic can be produced at significantly lower temperatures and under normal pressure conditions. “These nano-catalysts are long and very, very, very thin, and their structure take on more light absorption,” says Colmenares. “Thanks to the unique thermo-photocatalytic properties of manganese dioxide, the manganese rods have a much larger contact surface with the initial material molecules and are able to activate them better, so that practically all of the HMF is converted to DFF. 100%!”

Therefore, an LED lamp in the UV range and oxygen from the air at room temperature are sufficient for the conversion from HMF to DFF. “This is a waste-free process without the need for oxygen and additives [e.g. hydrogen peroxide H2O2],” says the professor happily. “The nano catalysts can also be used several times because the DFF doesn’t destroy them.”

Colmenares dispels concerns that the plastic might decompose too quickly and could, for example, lead to people drinking the compounds of drinking bottles. “No. It practically takes several years to decompose, but even if this reaction were to be faster, the consumer would only drink a small amount of ‘harmless’ plastic. One that is safe for the body. It is simply broken down by our intestinal bacteria and their enzymes.”

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