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
The CDC buried a measles forecast that stressed the need for vaccinations
This story was originally published on ProPublica, a nonprofit newsroom that investigates abuses of power. Sign up to receive our biggest stories as soon as they’re published. ProPublica — Leaders at the Centers for Disease Control and Prevention [...]
Light-Driven Plasmonic Microrobots for Nanoparticle Manipulation
A recent study published in Nature Communications presents a new microrobotic platform designed to improve the precision and versatility of nanoparticle manipulation using light. Led by Jin Qin and colleagues, the research addresses limitations in traditional [...]
Cancer’s “Master Switch” Blocked for Good in Landmark Study
Researchers discovered peptides that permanently block a key cancer protein once thought untreatable, using a new screening method to test their effectiveness inside cells. For the first time, scientists have identified promising drug candidates [...]
AI self-cloning claims: A new frontier or a looming threat?
Chinese scientists claim that some AI models can replicate themselves and protect against shutdown. Has artificial intelligence crossed the so-called red line? Chinese researchers have published two reports on arXiv claiming that some artificial [...]
New Drug Turns Human Blood Into Mosquito-Killing Weapon
Nitisinone, a drug for rare diseases, kills mosquitoes when present in human blood and may become a new tool to fight malaria, offering longer-lasting, environmentally safer effects than ivermectin. Controlling mosquito populations is a [...]
DNA Microscopy Creates 3D Maps of Life From the Inside Out
What if you could take a picture of every gene inside a living organism—not with light, but with DNA itself? Scientists at the University of Chicago have pioneered a revolutionary imaging technique called volumetric DNA microscopy. It builds [...]
Scientists Just Captured the Stunning Process That Shapes Chromosomes
Scientists at EMBL have captured how human chromosomes fold into their signature rod shape during cell division, using a groundbreaking method called LoopTrace. By observing overlapping DNA loops forming in high resolution, they revealed that large [...]
Bird Flu Virus Is Mutating Fast – Scientists Say Our Vaccines May Not Be Enough
H5N1 influenza is evolving rapidly, weakening the effectiveness of existing antibodies and increasing its potential threat to humans. Scientists at UNC Charlotte and MIT used high-performance computational modeling to analyze thousands of viral protein-antibody interactions, revealing [...]
Revolutionary Cancer Vaccine Targets All Solid Tumors
The method triggers immune responses that inhibit melanoma, triple-negative breast cancer, lung carcinoma, and ovarian cancer. Cancer treatment vaccines have been in development since 2010, when the first was approved for prostate cancer, followed [...]
Scientists Uncover Hidden Protein Driving Autoimmune Attacks
Scientists have uncovered a critical piece of the puzzle in autoimmune diseases: a protein that helps release immune response molecules. By studying an ultra-rare condition, researchers identified ArfGAP2 as a key player in immune [...]
Mediterranean neutrino observatory sets new limits on quantum gravity
Quantum gravity is the missing link between general relativity and quantum mechanics, the yet-to-be-discovered key to a unified theory capable of explaining both the infinitely large and the infinitely small. The solution to this [...]
Challenging Previous Beliefs: Japanese Scientists Discover Hidden Protector of Heart
A Japanese research team found that the oxidized form of glutathione (GSSG) may protect heart tissue by modifying a key protein, potentially offering a novel therapeutic approach for ischemic heart failure. A new study [...]
Millions May Have Long COVID – So Why Can’t They Get Diagnosed?
Millions of people in England may be living with Long Covid without even realizing it. A large-scale analysis found that nearly 10% suspect they might have the condition but remain uncertain, often due to [...]
Researchers Reveal What Happens to Your Brain When You Don’t Get Enough Sleep
What if poor sleep was doing more than just making you tired? Researchers have discovered that disrupted sleep in older adults interferes with the brain’s ability to clean out waste, leading to memory problems [...]
How to prevent chronic inflammation from zombie-like cells that accumulate with age
In humans and other multicellular organisms, cells multiply. This defining feature allows embryos to grow into adulthood, and enables the healing of the many bumps, bruises and scrapes along the way. Certain factors can [...]
Breakthrough for long Covid patients who lost sense of smell
A breakthrough nasal surgery has restored the sense of smell for a dozen long Covid patients. Experts at University College London Hospitals NHS Foundation Trust successfully employed a technique typically used for correcting blocked nasal passages, [...]