Tribune News Service
Chandigarh, August 30
Using a rare chemical process, researchers at a Mohali-based institute have developed a new kind of membrane that can detect toxic elements at industrial establishments or laboratories, thereby aiding in prevention of disasters.
Christened Mixed Matrix Membrane (MMM) that is made from two or more materials, it showed remarkable colour change when exposed to vapours of different amines, which are organic compounds derived from ammonia. This also opens new avenues for practical applications of nanomaterials.
Though ammonia or other amines are extensively used as raw material or intermediate products in chemical, fertilizer and food industries, they are highly toxic and corrosive, with the ability to disperse widely in the environment, according to scientists. They can also quickly oxidise in water to produce substances which are very hazardous. Even direct contact with amines can cause severe respiratory irritation and skin burns.
Using the ‘turn-on fluorescence process’, which is rare, a team at the Institute of Nano Science and Technology, Mohali, synthesized a highly water-stable ultrathin nickel-based nanosheet with a thickness of approximately 4.15 nano-metre. To compare, a typical sheet of paper is 1,00,000 nano-metre thick.
According to scientists, these nanosheets exhibited exceptional sensitivity in detecting amines and ammonia in an aqueous medium through a unique fluorescence process, which is rare. The researchers used them to fabricate an MMM that showed a colour change visible to the naked eye when exposed to ammonia and amines.
The colour change effect differs in each case enabling the membranes to visually distinguish different types of vapours. These membranes are also reusable and can be easily employed for real-time detection of amines. These nanosheets also have enhanced performance in various applications such as catalysis, gas separation and storage as compared to other alternatives, scientists said.
The laid down threshold limit for ammonia at workplaces is 50 ppm. Concentrations above this level can lead to severe and potentially fatal health issues. This makes detecting ammonia and amines, whether in vapour or liquid form, very important for effective environmental and water monitoring, and also for preventing onsite gas leakage and disasters.
