| Scientists from Nanyang Technological University, Singapore (NTU Singapore) have created a process that can upcycle most plastics into chemical ingredients useful for energy storage, using light-emitting diodes (LEDs) and a commercially available catalyst, all at room temperature. | |
| The new process is very energy-efficient and can be easily powered by renewable energy in the future, unlike other heat-driven recycling processes like pyrolysis. This innovation overcomes the current challenges in recycling plastics such as polypropylene (PP), polyethylene (PE) and polystyrene (PS), which are typically incinerated or discarded in landfills. Globally, only nine per cent of plastics are recycled, and plastic pollution is growing at an alarming rate. | |
| The biggest challenge of recycling these plastics is their inert carbon-carbon bonds, which are very stable and thus require a significant amount of energy to break. This bond is also the reason why these plastics are resistant to many chemicals and have relatively high melting points. | |
| Currently, the only commercial way to recycle such plastics is through pyrolysis, which has high energy costs and generates large amounts of greenhouse emissions, making it cost-prohibitive given the lower value product of the resulting pyrolysis oil. Developed by Associate Professor Soo Han Sen, an expert in photocatalysis from NTU’s School of Chemistry, Chemical Engineering, and Biotechnology, the new method uses LEDs to activate and break down the inert carbon-carbon bonds in plastics with the help of a commercially available vanadium catalyst. | |
| Published this week in the journal Chem (“Upcycling of non-biodegradable plastics by base metal photocatalysis”), the NTU method can upcycle a range of plastics, including PP, PE and PS. These plastics, together, account for over 75 per cent of global plastic waste. | |
| In developing a green solution to the plastic waste problem, the team wanted to ensure that minimal extra carbon emissions are generated through the recycling of plastics, which are long chains of molecules containing carbon atoms. | |
| Inventor Assoc Prof Soo said: “Our breakthrough not only provides a potential answer to the growing plastic waste problem, but it also reuses the carbon trapped in these plastics instead of releasing it into the atmosphere as greenhouse gases through incineration.” | |
How the plastics are broken down |
|
| First, the plastics are dissolved or dispersed in the organic solvent known as dichloromethane, which is used to disperse the polymer chains so that they will be more accessible to the photocatalyst. The solution is then mixed with the catalyst and flowed through a series of transparent tubes where the LED light is shone on it. | |
| The light provides the initial energy to break the carbon-carbon bonds in a two-step process with the help of the vanadium catalyst. The carbon-hydrogen bonds in the plastics are oxidised – making the bonds less stable and more reactive – after which the carbon-carbon bonds are broken down. | |
| After separation from the solution, the resulting end products are chemical ingredients such as formic acid and benzoic acid, which can be used to make other chemicals employed in fuel cells and liquid organic hydrogen carriers (LOHCs). LOHCs are now being explored by the energy sector as they play critical roles in clean energy development, given their ability to store and transport hydrogen gas more safely. | |
| Unlike current and other emerging technologies to recycle plastics such as pyrolysis, which uses a high-temperature process to melt and degrade the plastics into low-quality fuels, or carbon nanotubes and hydrogen, the new LED-driven method requires much less energy. | |
| Prof Soo adds that their method is unique in that it can use sunlight or LEDs powered with electricity from renewable sources such as solar, wind or geothermal, to completely process and upcycle such a wide range of plastics. This can allow for clean and energy-efficient management of plastics in a circular economy and increase the recycling rate of plastics. | |
| The process may also help Singapore to reduce the amount of plastic waste from being incinerated or landfilled, helping the country to meet its Zero-Waste Masterplan, where it aims to increase the overall recycling rate to 70 per cent by 2030 and reduce waste going to the Semakau landfill, estimated to run out of space by 2035. Singapore generates around 1 million tonnes of plastic waste annually and only six per cent of Singapore’s plastic waste is recycled. | |
| This study is part of a bigger project, entitled SPRUCE: Sustainable Plastics RepUrposing for a Circular Economy, which also involves Professor Xin (Simba) Chang, Associate Dean (Research) from the Nanyang Business School and Associate Professor Md Saidul Islam from the School of Social Sciences. | |
| The interdisciplinary team estimates that if Singapore can upcycle 80 per cent of its plastics, it could lead to at least a 2.1 million tonnes reduction in carbon dioxide emissions – about four per cent of the nation’s total greenhouse gas emissions. In addition, when plastics are upcycled into chemical feedstock, it reduces the need by the chemical industry to combust fossil fuels to produce chemical feedstock, further cutting down greenhouse gas emissions. | |
| Based on the estimations by Prof Chang and other team members, the economic benefit of reducing carbon dioxide emissions is estimated to be S$41.40m per year while the estimated cost savings from avoiding landfill use is about S$41.35 million per year in Singapore. Plastic reuse and recycling are projected to generate a profitpool growth of as much as US$60 billion for the chemical industry globally. | |
| Prof Chang, an expert in corporate finance, added, “Given that Singapore’s chemical industry accounts for about one-third of the manufacturing output in 2015, the integration of plastic upcycling technology into the industry has the potential to yield considerable positive economic and environmental impact.” | |
| Sociology expert Assoc Prof Islam said: “This innovative approach — by transforming plastic waste into valuable resources like formic acid — not only reduces the burden of plastic pollution but also addresses the growing demand for sustainable chemicals. This contributes to a cleaner environment, enhances public health, and creates new employment opportunities, especially in research, development, and production sectors, thereby fostering economic growth with a shift towards circular economies.” |
News
Scientists Unlock a New Way to Hear the Brain’s Hidden Language
Scientists can finally hear the brain’s quietest messages—unlocking the hidden code behind how neurons think, decide, and remember. Scientists have created a new protein that can capture the incoming chemical signals received by brain [...]
Does being infected or vaccinated first influence COVID-19 immunity?
A new study analyzing the immune response to COVID-19 in a Catalan cohort of health workers sheds light on an important question: does it matter whether a person was first infected or first vaccinated? [...]
We May Never Know if AI Is Conscious, Says Cambridge Philosopher
As claims about conscious AI grow louder, a Cambridge philosopher argues that we lack the evidence to know whether machines can truly be conscious, let alone morally significant. A philosopher at the University of [...]
AI Helped Scientists Stop a Virus With One Tiny Change
Using AI, researchers identified one tiny molecular interaction that viruses need to infect cells. Disrupting it stopped the virus before infection could begin. Washington State University scientists have uncovered a method to interfere with a key [...]
Deadly Hospital Fungus May Finally Have a Weakness
A deadly, drug-resistant hospital fungus may finally have a weakness—and scientists think they’ve found it. Researchers have identified a genetic process that could open the door to new treatments for a dangerous fungal infection [...]
Fever-Proof Bird Flu Variant Could Fuel the Next Pandemic
Bird flu viruses present a significant risk to humans because they can continue replicating at temperatures higher than a typical fever. Fever is one of the body’s main tools for slowing or stopping viral [...]
What could the future of nanoscience look like?
Society has a lot to thank for nanoscience. From improved health monitoring to reducing the size of electronics, scientists’ ability to delve deeper and better understand chemistry at the nanoscale has opened up numerous [...]
Scientists Melt Cancer’s Hidden “Power Hubs” and Stop Tumor Growth
Researchers discovered that in a rare kidney cancer, RNA builds droplet-like hubs that act as growth control centers inside tumor cells. By engineering a molecular switch to dissolve these hubs, they were able to halt cancer [...]
Platelet-inspired nanoparticles could improve treatment of inflammatory diseases
Scientists have developed platelet-inspired nanoparticles that deliver anti-inflammatory drugs directly to brain-computer interface implants, doubling their effectiveness. Scientists have found a way to improve the performance of brain-computer interface (BCI) electrodes by delivering anti-inflammatory drugs directly [...]
After 150 years, a new chapter in cancer therapy is finally beginning
For decades, researchers have been looking for ways to destroy cancer cells in a targeted manner without further weakening the body. But for many patients whose immune system is severely impaired by chemotherapy or radiation, [...]
Older chemical libraries show promise for fighting resistant strains of COVID-19 virus
SARS‑CoV‑2, the virus that causes COVID-19, continues to mutate, with some newer strains becoming less responsive to current antiviral treatments like Paxlovid. Now, University of California San Diego scientists and an international team of [...]
Lower doses of immunotherapy for skin cancer give better results, study suggests
According to a new study, lower doses of approved immunotherapy for malignant melanoma can give better results against tumors, while reducing side effects. This is reported by researchers at Karolinska Institutet in the Journal of the National [...]
Researchers highlight five pathways through which microplastics can harm the brain
Microplastics could be fueling neurodegenerative diseases like Alzheimer's and Parkinson's, with a new study highlighting five ways microplastics can trigger inflammation and damage in the brain. More than 57 million people live with dementia, [...]
Tiny Metal Nanodots Obliterate Cancer Cells While Largely Sparing Healthy Tissue
Scientists have developed tiny metal-oxide particles that push cancer cells past their stress limits while sparing healthy tissue. An international team led by RMIT University has developed tiny particles called nanodots, crafted from a metallic compound, [...]
Gold Nanoclusters Could Supercharge Quantum Computers
Researchers found that gold “super atoms” can behave like the atoms in top-tier quantum systems—only far easier to scale. These tiny clusters can be customized at the molecular level, offering a powerful, tunable foundation [...]
A single shot of HPV vaccine may be enough to fight cervical cancer, study finds
WASHINGTON -- A single HPV vaccination appears just as effective as two doses at preventing the viral infection that causes cervical cancer, researchers reported Wednesday. HPV, or human papillomavirus, is very common and spread [...]
