Abu Dhabi: A team of researchers at NYU Abu Dhabi (NYUAD) has developed a process to upcycle single-use plastic bags and disposable masks into “carbon dots”, a carbon-based nanomaterial. The single-step hydrothermal process is non-toxic because it does not require any organic solvents, and it converts polyethylene-based plastic bags and polypropylene-based surgical masks into carbon dots. These can then be used for purposes of environmental monitoring, disease diagnosis, and treatment.
An estimated 26,000 tonnes of pandemic-related plastic waste – from medical waste to online shopping packaging – have been released into the world’s oceans, making it even more urgent to find efficient methods to upcycle this non-degradable material.
One solution is to convert the single-use plastic into so-called carbon dots, which are carbon nanomaterials that are biocompatible, and are highly favoured for applications in the fields of biological imaging, environmental monitoring, chemical analysis, targeted drug delivery, disease diagnosis and therapy, and anti-counterfeiting.
Existing methods to upcycle plastic into carbon dots involve multiple, time-consuming steps, and require the use of toxic chemicals.
In the NYUAD study titled ‘High-yield, One-pot Upcycling of Polyethylene and Polypropylene Waste into Blue-Emissive Carbon Dots’, which was published in the journal Green Chemistry, the Abu Dhabi-based researchers presented the development of a new synthesis method. The process presents a “simple, cost-effective, and scalable” approach to upcycling plastic waste. This oxidative degradation method can also upcycle plastics contaminated with organic waste such as food scraps, which poses a significant challenge to traditional recycling technologies.
The project’s senior author is Khalil Ramadi, assistant professor of Bioengineering at NYUAD. Mohammed Abdelhameed, a scientist at NYUAD, and Mahmoud Elbeh, an NYUAD undergraduate student, are first authors.
The researchers also estimated the economic feasibility of the synthetic method by comparing the variable costs of this process to existing chemical recycling processes, considering the economic value of the created carbon dots.
The researchers also estimated the economic feasibility of the synthetic method by comparing the variable costs of this process to existing chemical recycling processes, considering the economic value of the created carbon dots. They found that the global market value of carbon dots is expected to reach $6.4 billion (around Dh23.5 billion) by 2025, up from $2.4 billion (around Dh8.8 billion) in 2019. This indicates that the nanomaterial has a commercial value that justifies the associated processing costs.
The high volume of single-use plastics used during the pandemic, particularly surgical masks and medical waste, presents an increased need to find a solution for managing non-biodegradable waste.
It is also estimated that only 14 per cent of the eligible plastic packaging – whose use has surged due to the boom in online shopping – is recycled, with the rest ending up in landfills and oceans, where it does considerable harm. These materials can be consumed by organisms or fragmented into micro- and nano-plastics that can threaten terrestrial, marine, and freshwater ecosystems and, ultimately, human health.
“The new method our team has developed is a cost-effective and safe method that can be easily implemented to significantly reduce the amount of harmful plastic that is released into our ecosystems. In addition to providing a new tool to protect our ecosystems, this approach can efficiently and responsibly produce carbon dots, a versatile nanotechnology whose potential applications are nearly boundless,” Ramadi said.
“We’re very delighted to further support the UAE’s Circular Economy Policy. Given that we are tackling the plastic waste crisis by creating a valuable product using a relatively easy-to-implement method, we’re looking forward to more collaborations to not only scale up this project but also utilise the produced dots for further development and applications,” Elbeh added.