Researchers have synthesised a sensitive sensor that can detect minute traces of pollutants such as nitrophenols found in industrial wastewater, making it potentially useful for monitoring the levels of such contaminants in environmental samples1.
Nitrophenols are widely used in the synthesis of various products that include dyes, pesticides and pharmaceuticals. The US-based Environmental Protection Agency has categorised nitrophenols as hazardous compounds. Existing methods for detecting these pollutants are complex and time consuming.
In search of a method that can rapidly detect nitrophenols, scientists from the Maharaja Sayajirao University of Baroda in Vadodara, India, prepared carbon nanoparticles from powder made from palm shell waste. They then converted the nanoparticles into carbon quantum dots by treating them with a specific acid.
The sensor, made from the carbon quantum dots, was exposed to various nitrophenol-containing solutions. On exposure to nitrophenols, the sensor exhibited green fluorescence. The fluorescence intensity of the sensor increased with increasing pH levels of the solutions.
The sensor selectively detected nitrophenols even in the presence of other organic pollutants, such as phenol, chlorophenol and other pollutants. The sensor showed a rapid response. Since the fabrication process is green and the sensor is stable, it could potentially be used to track pollutants in real time in contaminated environmental samples.