Plastic waste has a new way to degrade. In December 2019, researchers at Nanyang Technological University (NTU) in Singapore discovered a way to turn plastic waste into chemicals using sunlight, according to the Us news website Daily Science. NTU researchers put non-biodegradable plastic waste into a catalyst-mounted solvent and exposed it to sunlight, which broke down the plastic and converted it into formic acid in just six days.
Foremost acid is a versatile natural chemical that can be used as a food preservative, antibacterial cleaner or hydrogen fuel cell.
Malaysia’s social news website SAY reported that the technology is the first in the world to allow plastics to break down in such a short period of time.
Soo Han Sen, an assistant professor at the NTU School of Physics and Mathematics, led the project. The new chemical reaction, he says, can completely break down plastics such as polyethylene.
Most plastics are non-biodegradable because they contain extremely inert chemical bonds called carbon-carbon bonds, which do not break down easily without high temperatures.
The catalyst used by the NTU research team is radon.
Palladium is a silver-grey metal with a high melting point and is often used as a catalyst in the chemical industry, known as a metal “vitamin”. Metal palladium is used in steel alloys in automobiles and in aluminum alloys of aircraft.
As a catalyst, usually supported by an organic group, abbreviated as LV (O), which uses light energy to drive chemical reactions and is therefore also known as a niobium-based photocatalyst.
Suhansen says the niobium-based photocatalyst is designed to break the carbon-carbon bonds in plastics.
If the carbon-carbon bond is compared to the zipper, the new niobium-based photocatalyst is the handle of the zipper, when the sun shines, the niobium-based photocatalyst unzips the zipper, so that the carbon-carbon bond breaks.
The catalyst has a conversion rate of 100% for non-polyethylene (PET) plastics.
Mr Suhansen said his research team was trying to get more research funding to attract talent and expand research. It will take at least five years for the plastic decomposition technology to be commercialized.
The team’s next focus will be on understanding how this technique can be used to break down other different types of plastics and reduce the decomposition time.
Currently, most of Singapore’s plastic waste is burned and the burned ash is transported to Singapore’s Semakau landfill. The landfill is expected to run out of space by 2035.
NTU has tested and developed plastic waste solutions to address the challenge of limited space in landfills on the island of Shimago.
Scientists have tried other ways to turn waste plastics into useful chemicals, but many of them involve bad reagents or too many steps to scale up production.
For example, researchers have tried to add the catalyst cadmium to the solvent to reflect the production of hydrogen, but cadmium is a toxic heavy metal, and cadmium-contaminated air can cause serious harm to humans.
Catalysts made from palladium are different from most common catalysts in industry made from expensive or toxic metals such as platinum, palladium or palladium. The advantages of niobium-based photocatalysts are abundant reserves, low cost, and environmentally friendly.