UK-based researchers have invented a simple sunlight-driven method for transforming plastic waste into usable hydrogen and some chemicals. The researchers, from the University of Cambridge, have discovered a method that employs quantum dots made of cadmium sulfide for the photocatalysis and degradation of plastics.
In the process of transforming plastic waste into usable hydrogen, referred to as photoreforming, the photocatalyst is dropped onto the plastic, which is then immersed in an alkaline solution. With the help of irradiation using sunlight, the water from solution is reduced to hydrogen and the plastic is simultaneously oxidized to tiny organic molecules.
The researchers examined the system for three common types of polymers – polyethylene terephthalate, polylactic acid, and polyurethane. The results were comparable to technologically advanced photocatalysis techniques that employ costly sacrificial reagents. In this method, the generation of hydrogen from polymers at ambient temperature and pressure requires a substrate, a photocatalyst, water, and sunlight.
For the proper recycling and transformation of plastics into usable and useful plastics, clean and pure materials are required. The recycling of plastics contaminated with oil or food becomes almost impossible as the contaminations impede the recycling process. However, this is not an issue with the new method. The use of the process in real-life scenario was demonstrated by the researchers with the use of a plastic bottle that photoreformed to hydrogen with a level of efficiency close to pure polymers.
With further evolution, the method could become a reliable and effective additional method of treating waste that is marked as non-recyclable. The researchers feel that to make the technology economically viable, further research is required in the field of bulk plastic solid waste polymers.