Hydrated electron-based degradation of atenolol in aqueous solution

Abstract

Abstract Photoactivation of SO 3 2− with UV 254 irradiation (UV/SO 3 2− ) was used to generate hydrated electron (e aq − )-based process to degrade atenolol (ATL) in drinking water. The decontamination mechanism of UV/SO 3 2− process was investigated by means of competitive kinetic analysis and identification of transformation products, followed by the assessment of potential for drinking water treatment through evaluating the influence of operational parameters (dosage of SO 3 2− , solution pH, HCO 3 − , dissolved organic matters (DOM), and temperature), detoxification efficiency, and technical economy. The kinetic and transformant observations lead to the suggestion that e aq − -induced dissociative electron capture and addition reactions be involved in the ATL degradation mechanism. The results show a positive correlation between the ATL removal efficiency and dosage of SO 3 2− (0.5–2.0 mM). The process is also pH-dependant. Increasing solution pH from 5 to 9 promoted the elimination of ATL due to the pH-dependent SO 3 2− photoactivity. For the pH increase from 9 to 11, deprotonation of ATL caused further enhancement of ATL destruction. 1–4 mM HCO 3 − exerted little inhibition effect on the ATL destruction, while the presence of 1 and 4 mg L −1 L DOM deteriorate the ATL degradation due to the effective UV fluence decrease. In addition, for every 10 °C the solution temperature rose, the reaction rate increased 1.3–1.6 times. The toxicity evaluation further suggests that ATL degradation and detoxification do not occur simultaneously. Compared to UV/H 2 O 2 or UV/OXONE process, UV/SO 3 2− process was more energy-consuming.