Catalyzation of UV/H2O2 System by Ferrous Ions for Degradation of Paracetamol: Kinetics, Mechanism, and Toxicity Evaluations

Paracetamol (PCM) is extensively used for the treatment of various diseases and is frequently released into aquatic environments, resulting in considerable environmental concerns. In the current study, UV, UV/H2O2, and photo-Fenton approaches were applied for the degradation of PCM. The removal of PCM (10 mg/L) was achieved to be 11.2% by UV alone, after 60 min of irradiation. However, the UV/H2O2 system degraded 91.4% of PCM after 60 min at pH 6.0, demonstrating that the combination of UV and H2O2 (5 mM) significantly improved the removal efficiency of PCM. Moreover, the addition of Fe2+ (1 mg/L) to the UV/H2O2 system further enhanced the degradation of PCM, obtaining 100% removal at pH 3 after 45 min of reaction. The UV/H2O2 process showed higher efficiency at 6.0 than at pH 3.0 and 11.0, as evident by the respectivekobs values of 0.0331, 0.0437, and 0.0279 min−1.However, compared to pH 6.0, the UV/H2O2/Fe2+ process showed greater reactivity at pH 3.0. Additionally, nitrate, chloride, bicarbonate, and carbonate ions slightly impeded the removal of PCM in both processes. Furthermore, the TOC removal for UV/H₂O₂ and photo-Fenton techniques was measured to be 65.3 and 83.5%, respectively, after 180 min. In addition, the total cost for the UV/H2O2 process for one order removal (90% removal) of PCM was calculated to be 1.43 $ m−3. Moreover, two degradation products (DPs) of PCM were identified using GC/MS analysis. The computational investigation was performed for toxicological measurements of identified DPs. The current work showed that PCM could be effectively degraded and mineralized using both UV/H2O2 and photo-Fenton techniques.