Degradation of Paracetamol by an UV/Chlorine Advanced Oxidation Process: Influencing Factors, Factorial Design, and Intermediates Identification

• Main Authors: Yen Hai Dao, Hai Nguyen Tran, Thien Thanh Tran-Lam, Trung Quoc Pham, Giang Truong Le
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: paracetamol; UV/chlorine; reaction kinetics; response surface methodology; transformation products
• Online Access: https://www.mdpi.com/1660-4601/15/12/2637

The combination of a low-pressure mercury lamp and chlorine (UV/chlorine) was applied as an emerging advanced oxidation process (AOP), to examine paracetamol (PRC) degradation under different operational conditions. The results indicated that the UV/chlorine process exhibited a much faster PRC removal than the UV/H₂O₂ process or chlorination alone because of the great contribution of highly reactive species (^&#8226;OH, ^&#8226;Cl, and ClO^&#8226;). The PRC degradation rate constant (<i>k</i>_obs) was accurately determined by pseudo-first-order kinetics. The <i>k</i>_obs values were strongly affected by the operational conditions, such as chlorine dosage, solution pH, UV intensity, and coexisting natural organic matter. Response surface methodology was used for the optimization of four independent variables (NaOCl, UV, pH, and DOM). A mathematical model was established to predict and optimize the operational conditions for PRC removal in the UV/chlorine process. The main transformation products (twenty compound structures) were detected by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS).