MANDI: The plastics, a modern villain of environment, will be a thing of the past as Indian Institute of Technology Mandi researchers have developed a method that can transform plastic into hydrogen, a gas that is being tipped as the non-polluting fuel of the Future.
According to the IIT Mandi, the generation of hydrogen from plastics is particularly useful because the gas is considered the most practical non-polluting fuel of the future. The research also promises production of useful chemicals such as lactic acid, formic acid and acetic acid from plastics.
Plastics, most of which are derived from petroleum, are not bio-degradable: They cannot be easily broken down into harmless products.
The scale of plastic menace has assumed alarming proportion in the world. It is said that most of the 4.9 billion tonnes of plastics ever produced would end up in landfills, threatening human health and the environment.
Fuelled by the need to prevent runaway plastic pollution, IIT Mandi researchers are developing methods that can transform plastic into useful chemicals such as lactic acid, formic acid and acetic acid.
This study was funded by the Scheme for Promotion of Academic and Research Collaboration (SPARC), Ministry of Education. The findings from this work have been recently published in the Journal of Environmental Chemical Engineering.
The research 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. scholars, Ms Rituporn Gogoi, Ms Astha Singh, Ms Vedasree Moutam, Ms Lalita Sharma, Ms Kajal Sharma.
Professor, School of Basic Sciences, IIT Mandi, Dr Prem Fexil Siril said, “The ideal path to effective annihilation of plastics is to degrade them into useful chemicals. The generation of hydrogen from plastics is particularly useful as hydrogen gas is considered the most practical non-polluting fuel of the future.”
IIT Mandi researchers have developed a catalyst that can efficiently convert plastics into hydrogen and other useful chemicals when exposed to light. “Catalysts are substances that drive otherwise difficult or impossible reactions and when they are activated by light, they are called photocatalysts”, researchers explained.
The IIT Mandi's photocatalyst combines iron oxide in the form of nanoparticles (particles a hundred thousand times smaller than the diameter of a single hair strand), with a conducting polymer -polypyrrole. “This combination results in formation of a semiconductor-semiconductor heterojunction, which in turn, results in strong visible-light-induced photocatalytic activity”.
Photocatalysts usually need Ultra Violet light for activation and therefore require special bulbs. “The IIT Mandi catalyst can function simply with sunlight”, they emphasized.
Dr. Prem Felix Siril further explained, “We first ascertained the photocatalytic activity of our catalyst by seeing its action on methyl orange, whose colour change from orange to colourless showed the extent to which our catalyst was able to degrade it.”
The researchers found there was 100% degradation within four hours when they used a catalyst in which about 4% weight iron oxide was present in the polypyrrole matrix. “The researchers then tested this catalyst on polylactic acid (PLA), a plastic that is extensively used in food packaging, textiles, medical articles and cosmetics”.
The team found that hydrogen was evolved during the breakdown of PLA when the catalyst was exposed to visible light. "The generation of hydrogen is good in itself, we are even more excited about the absence of carbon dioxide”, said Dr Prem Felix Siril.
More significant is while most other photocatalysts that have been developed for hydrogen generation from plastics, release the greenhouse gas as a by-product, but the IIT Mandi catalyst did not, instead co-produced useful chemicals such as lactic acid, formic acid and acetic acid, he found.
