New Delhi, March 23 (India Science Wire): In a significant development in environmental pollution, a team of researchers from the Indian Institute of Technology (IIT)-Mandi has developed a method that promises to help turn plastic into hydrogen when exposed to light. Generating hydrogen from plastics is expected to be more useful as hydrogen is seen as the most practical non-polluting fuel of the future.
Plastics, most of which are derived from petroleum, are not biodegradable. They cannot be easily broken down into harmless products. It is feared that most of the 4.9 billion tons of plastics ever produced end up in landfills, threatening human health and the environment.
In the new study, the researchers developed a photocatalyst that efficiently converts plastics into hydrogen and other useful chemicals when exposed to light. The substance combines iron oxide in the form of nanoparticles (particles a hundred thousand times smaller than the diameter of a single strand of hair), with polypyrrole, which is a conductive polymer.
The researchers found that the combination resulted in the formation of a semiconductor-semiconductor heterojunction, resulting in strong visible light-induced photocatalytic activity. Photocatalysts generally need UV light for activation and therefore require special bulbs. The newly developed catalyst can work with sunlight itself.
The researchers found 100% degradation in four hours when they used the catalyst in which iron oxide was present in the polypyrrole matrix at a ratio of about 4% by weight. The researchers tested it on polylactic acid, a plastic widely used in the food packaging, textiles, medical items and cosmetics industries.
“While hydrogen generation is good on its own, we are even more pleased that no carbon dioxide was produced as a byproduct,” the scientists said. Most other photocatalysts that have been developed for the generation of hydrogen from plastics release greenhouse gases as a byproduct. Instead, the new catalyst co-produced several useful chemicals such as lactic acid, formic acid, and acetic acid.
The study was funded by the Program for Promoting Academic and Research Collaboration (SPARC) of the Ministry of Education. It was led by Dr. Prem Fexil Siril, Professor, School of Basic Sciences, IIT Mandi, and Dr. Aditi Halder, Associate Professor, School of Basic Sciences, IIT Mandi, and co-authored by their Ph.D. academics, Ms. Rituporn Gogoi, Ms. Astha Singh, Ms. Vedasree Moutam, Ms. Lalita Sharma and Ms. Kajal Sharma. They published a report on their findings in the Journal of Environmental Chemical Engineering.