Photolysis of sulfadiazine under UV radiation: Effects of the initial sulfadiazine concentration, pH, NO3- and Cd2+

The photolytic behaviour of sulfadiazine (SD) under ultraviolet (UV) radiation was investigated. The results showed that the SD photolysis fitted quasi-first-order kinetics model. The acid condition is favourable to the UV photolysis of SD because of more free radicals compared to the neutral and cationic conditions. NO3- inhibited the SD photolysis, which may be resulted from the competition of NO3- with SD for UV. Conversely, Cd2+ could promote the SD photolysis, because the metal ions reduce the reaction activation energy of the rate determining step. This research could serve as reference for SD photolysis contained in wastewater under UV radiation.