New Low-Cost Method to Clean Toxic Chromium from Water Using Sunlight

Scientists at the Institute of Nano Science and Technology (INST) in Mohali have created a new, low-cost way to remove toxic chromium from industrial wastewater. This method uses sunlight as a catalyst and combines it with advanced microfluidic technology.

Chromium is a harmful chemical often found in wastewater from industries like leather tanning and electroplating. The most dangerous form, hexavalent chromium, is harmful to people even in small amounts. According to the World Health Organization (WHO), safe levels in drinking water are very low, making it important to remove this toxic substance.

Traditional methods to clean chromium from water can be expensive and not very effective. But Dr. Bhanu Prakash’s research group at INST has found a better solution. They use sunlight to help convert the harmful hexavalent chromium into a safer form called trivalent chromium. This process, called continuous flow photoreduction, uses special nanoparticles and can even be monitored using a smartphone.

One of the best things about this new method is that it’s not only cheap, but it also uses renewable energy like sunlight. The microfluidic technology allows the scientists to adjust the process for better results, like changing the flow rate or the design of the reactor. This makes the cleaning process very efficient, reaching up to 95% effectiveness.

The researchers started by creating tiny microreactors and special nanocatalysts. They then tested how well these worked to clean the water by measuring changes using UV-Vis spectroscopy, which checks the color of the water. They also made sure that the reactors and catalysts could be used many times without losing their effectiveness.

Their findings, published in the Chemical Engineering Journal, show that this method could be used on a larger scale by setting up multiple microreactors or by improving the design of bigger reactors. This new approach could make cleaning industrial wastewater much more efficient and affordable.