Throwing away used plastics is convenient for human beings, but for the environment, it is a disaster. Yet, as long as the plastics are properly recycled, the value is definitely not limited to one-time. Scientists have recently developed a new catalytic method that can convert plastics into lubricants, oils, detergents and even cosmetics in order to reduce environmental pollution and improve recycling.
Nearly 400 million tons of new plastic products are produced worldwide each year, a figure that could quadruple by 2050. Yet, about three-quarters of plastics have been discarded once and are not properly recycled. It takes thousands of years to decompose in the natural environment, and we’ve heard countless cases of marine animals dying from eating plastic by mistake.
So, how can we convert the disposable plastics into high-quality products? Although plastics can be fused and reprocessed, this recycling method can only produce low-value materials. An example of this is the use of recycled plastic bottles to make park benches. The limited use of the traditional recycling methods has prompted scientists from Northwestern University, Argonne National Laboratory and Ames Laboratory to develop a new catalytic method, which can potentially convert the polyethylene molecules from plastics into value-added commercial products.
The catalyst for the new method consists of platinum nanoparticles — each a mere two nanometers in size — that are deposited on perovskite nanocuboids about 50 to 60 nanometers in size. It is a difficult task to deposit the nanoparticles of one material on the larger nanoparticles of another material. Thus, the Argonne National Laboratory team has also developed an atomic layer deposition technique to precisely control the nanoparticles.
At a moderate pressure and temperature, the catalyst can crack the plastic’s strong carbon-carbon bonds and convert them into high-quality liquid hydrocarbons, which can be applied to oils, lubricants or waxes, and can be further processed into one of the components of detergents and cosmetics.
In the past, fusing plastics or using general catalysts may produce greenhouse gases and toxic by-products, but the new catalytic method can produce much less waste during the process. Although catalysts can be designed better, the results now seem to be more or less helpful to the planet’s biggest problems.
The new paper was published in the journal ACS Central Science.