A special glass with the help of sunlight can purify water

News Bharati    06-May-2019
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Mandi, May 6: Wastewater management is the biggest challenge in front of any civic body management system. Wastewater from pharmaceutical and textile industry is a major source of river pollution. Scientists at IIT Mandi have developed a self-cleaning glass that can remove microbes and organic pollutants -- like dyes, detergent and drugs -- from wastewater, using only sunlight.

 

While existing purification techniques can remove solid pollutants as well as dissolved inorganic compounds, removing dissolved organic compounds remain a challenge, said Rahul Vaish, associate professor at Indian Institute of Technology (IIT) Mandi in Himachal Pradesh.

Vaish recommends the use of the process known as photocatalysis to treat the wastewater before the harmful contaminants make their way into our river streams. The IIT team has developed a transparent calcium borate glasses and TiO2, Titanium Dioxide crystalized glass nanocomposites which can kill microbes and break down organic chemicals in the presence of solar light. “These glasses have photocatalytic and self-cleaning properties which help in destroying the bacteria and other microbes from wastewater in the presence of sunlight”. Vaish said.

These easy to fabricate glasses can be made in the form of large panels which can have a wide range of cleaning, from small bottles to large tanks for industrial discharge. This glass can also remove detergent from the water. It can be used in washing machines. All these experiments are successfully tested in the laboratory. However, cost and efficiency associated with existing technology is a major hurdle in their commercial usage.

What is Photocatalysis?

Photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalysed photolysis, light is absorbed by an adsorbed substrate. Catalyst is the mediator which helps in reacting in the reaction. In photo-generated catalysis, the photocatalytic activity (PCA) depends on the ability of the catalyst to create electron-hole pairs, which generate free radicals (e.g. hydroxyl radicals: •OH) able to undergo secondary reactions. Its practical application was made possible by the discovery of water electrolysis by means of titanium dioxide (TiO2).