Photo-degradation of atrazine in water using UV and investigating its by-products

Atrazine is one of the most widely used chlorinated herbicides with properties, such as sustainability in soil and ability to penetrate into water sources. This study aimed to investigate the photo-degradation of atrazine using ultraviolet ray and to identify its by-products. The efficiency of atrazine removal under UV irradiation with a power of 6-125 watts was investigated and some effective parameters, such as initial concentration (10-100 mg/l) and pH (3-5), were studied during the radiation period (5-90 minutes). In all experiments, the volume of the solution used in 250-ml Erlenmeyer flask was 100 ml. After all, the final and by-products produced during this process were identified by mass gas chromatography. The results showed that the removal efficiency did not change significantly by increasing pH. With increasing lamp power from 6 to 125 watts at one hour, the degradation efficiency increased by 24.5%, 23.5%, and 29.7% at concentrations of 10, 30, and 50 mg/l, respectively. Also, by increasing time from 5 to 15 minutes under the 125-watt radiation, the removal efficiency increased from 45.6 to 96.8%. Examining the results of mass gas chromatography revealed that atrazine photolysis process progressed towards the mineralization of atrazine. Accordingly, organic chlorine transformed to chlorine ion and organic nitrogen involved in ammonium and nitrate molecules. Overall, the results indicated that photolysis at the wavelength of 254 nm could be used along with other purification methods to completely remove atrazine and simultaneously disinfect contaminated water sources.