A team led by researchers at Virginia Polytechnic Institute and State University (USA) has developed a new recycling method plastics It is converted into high-value chemicals known as surfactants used for create soap, detergent and other similar items. It’s a revolutionary discovery that could mean a hitherto unknown commercial outlet for a planet-wide hazardous waste.
Plastics and soaps have little in common in terms of texture, appearance, and most importantly, the way they are used. However There is a surprising connection between the two elements at the molecular level.: The chemical structure of polyethylene, one of the most widely used plastics in the world today, is strikingly similar to the fatty acid used as a chemical precursor in soap making. Both materials are made up of long chains of carbon, but fatty acids have an extra group of atoms at the end of the chain.
Guoliang ‘Greg’ Liu, an associate professor of chemistry at Virginia Tech’s College of Science, has long felt that: this similarity meant that it should be possible to convert polyethylene into fatty acids and produce soap with a few additional steps.. The challenge was how to split a long polyethylene chain into very short but not very short chains and how to do this efficiently. Liu believed there was potential for a new recycling method that would take low-value plastic waste and turn it into a useful, high-value product.
Liu was inspired while enjoying a winter night by the fireplace. He looked at the smoke from the fire and thought about how the smoke was made up of tiny particles formed during the burning of wood. Although plastics should never be burned in a fireplace for health and safety reasons, Liu began to wonder if polyethylene could be burned in a laboratory. Does incomplete combustion of polyethylene produce smoke like burning wood? If someone were to catch this smoke, what would it be made of?
“Firewood is mainly made of polymers such as cellulose. Combustion of wood breaks these polymers down into short chains and then into small gas molecules before complete oxidation to carbon dioxide,” said Liu. “Similarly, if we break up synthetic polyethylene molecules, but stop the process before they break down into small gas molecules, then we get short-chain polyethylene-like molecules,” he said.
Gotta get wax from plastic
With the help of two other scientists, Liu They built a small furnace-like reactor where they could heat the polyethylene in a process called temperature gradient thermolysis.. At the bottom the furnace is at a high enough temperature to break the polymer chains and at the top the furnace is cooled to a low enough temperature to prevent further breakage. After thermolysis, they collected the sludge, similar to cleaning soot in a fireplace, and found that Liu’s hunch was correct: It consisted of ‘short chain polyethylene’, or rather waxes.
Liu explained that this is the first step in developing a method to turn plastic into soap. After several steps, including saponification, team made the world’s first plastic soap. The team enlisted the help of computational modeling and economic analysts to continue the process.
“Our research shows that a new way to recycle plastic without using new catalysts or complex procedures. “In this study, we demonstrated the potential of a dual strategy for plastic recycling.” Science. “This will encourage more people to develop more creative designs for recycling procedures in the future.”
Advantages of the invention method
Although the plastic that inspired this project was polyethylene, The method may also work with another type of plastic known as polypropylene.. These two materials make up most of the plastic consumers encounter every day, from product packaging to food packaging to fabrics.
One of the most interesting features of Liu’s new recycling method is, can be used on both plastics at the same time, so no need to separate. This is a huge advantage over some of the recycling methods used today, which require careful separation of plastics to avoid contamination. This separation can be quite difficult due to how similar the two plastics are to each other.
Another benefit of the recycling technique is that it has some features. very simple requirements: plastic and heat. The initial transformation of the plastic is a simple reaction, although some additional ingredients are required in the final steps of the process to convert the wax molecules into fatty acids and soap. This adds to the method’s cost-effectiveness and relatively small environmental impact.
Economic value of the find
For recycling to be effective on a large scale, the end product must be sufficiently valuable. to cover the costs of the process and make it more economically attractive than alternative recycling options
While soaps may not seem like a particularly expensive product at first, they can be double or triple the price of plastics by weight. Currently the average soap and detergent price is around $3,550 per metric ton and polyethylene costs around $1,150 per metric ton. Also, the demand for soaps and related products is comparable to the demand for plastics.
Liu said this research lays the groundwork for a new way to reduce waste by diverting used plastics to the production of other useful materials. over time andWe expect recycling facilities around the world to start implementing this technique.. If so, consumers can one day hope to have the opportunity to purchase revolutionary sustainable soap products that also lead to a reduction in plastic waste in landfills.
“It should be noted that plastic pollution is more of a global problem than a problem of a few countries. Compared with a sophisticated process and complex catalyst or reagent, a simple process could be more accessible to many other countries around the world‘, he added. ‘I hope this can be A good start to the fight against plastic pollution”.
Reference work: https://www.science.org/doi/10.1126/science.adh0993
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