CHENNAI: A research team from Crystal Growth Centre of Anna University has found an easy way to treat dyes and organic contaminants in industrial waste water using sunlight. The team, led by assistant professor Shubra Singh and her students Durga Shankar Vavilapalli and R Janani, is working on novel materials like Brownmillerite, structured calcium ferrite, and Zinc based chalcogenide, that can do wonders in removing water pollutants under sunlight.
Speaking to TNIE, Singh claimed the materials synthesized by them are “visible light” photoactive and able to degrade certain toxic organic pollutants found in contaminated water under natural sunlight irradiation. Sunlight which reaches after being filtered by atmosphere, consists of 3-5% ultraviolet light, 43-45% visible light and 52-55% infrared light. Unlike conventional UV technologies, the team utilizes low cost methods using visible spectrum of sunlight.
“When the contaminated water is treated with material synthesized from our lab under sunlight irradiation, it produces active species such as hydroxyl radicals which break down the molecules of the toxic organic contaminants. We are working on materials to degrade pollutants such as Methylene Blue and synthetic compounds such as Ciprofloxacin.
Methylene Blue is commonly used as textile dye and also as medication to treat methemoglobinemia (a blood disorder in which too little oxygen is delivered to cells). Ciprofloxacin is a fluoroquinolone, a common synthetic antibiotic of quinolone drug class. This method is called photocatalysis,” Shubra Singh explained.
These materials are more efficient and cost effective as the yield of synthesis can be increased manifold. Several conventional technologies used currently in the industrial level are either expensive or lead to secondary pollutants. The rate at which the targeted pollutants can be degraded by these materials is very high. Now, the team is collaborating with IIT Madras. A proposal has been submitted to the Science and Technology Department to test these materials on antibiotic residues found in freshwater sources.