Degradation of oxcarbazepine by UV-activated persulfate oxidation: kinetics, mechanisms, and pathways

Abstract

The degradation kinetics and mechanism of the antiepileptic drug oxcarbazepine (OXC) by UV-activated persulfate oxidation were investigated in this study. Results showed that UV/persulfate (UV/PS) process appeared to be more effective in degrading OXC than UV or PS alone. The OXC degradation exhibited a pseudo-first order kinetics pattern and the degradation rate constants (k obs) were affected by initial OXC concentration, PS dosage, initial pH, and humic acid concentration to different degrees. It was found that low initial OXC concentration, high persulfate dosage, and initial pH enhanced the OXC degradation. Additionally, the presence of humic acid in the solution could greatly inhibit the degradation of OXC. Moreover, hydroxyl radical (OH•) and sulfate radical (SO4 (-)••) were identified to be responsible for OXC degradation and SO4 (-)• made the predominant contribution in this study. Finally, major intermediate products were identified and a preliminary degradation pathway was proposed. Results demonstrated that UV/PS system is a potential technology to control the water pollution caused by emerging contaminants such as OXC.

Comparative study of the toxicity between three non-steroidal anti-inflammatory drugs and their UV/Na2S2O8 degradation products on Cyprinus carpio

“…Advanced oxidation processes (AOPs) are the most commonly used tertiary treatment in refractory pollutants degradation. Ultraviolet light/Na 2 S 2 O 8 (UV/PS), one of the typical UV-based AOPs 22 , has attracted more interest due to the higher oxidation ability of sulfate radicals (SO 4 −• ). The redox potential of SO 4 −• is 2.6~3.1 V 23 , which is higher than that of ·OH(1.8~2.7 V), especially at neutral pH.…”

Chemically and thermally activated persulfate for theophylline degradation and application to pharmaceutical factory effluent

“…PS and H 2 O 2 are the two most commonly used effective oxidants in AOPs; however, PS poses some advantages over H 2 O 2 in terms of cost, safety in handling, and ease of access in some regions. PS is effective in degrading several pharmaceuticals; [31][32][33][34] however, to our knowledge, it has not been tested by other research groups to treat TP. The main PS activation methods are UV, chemical, and heat activation, which generate highly reactive sulfate radicals (SRs) (eqn (1)-(3)).…”

Epigallocatechin-3-gallate-coated Fe 3 O 4 as a novel heterogeneous catalyst of peroxymonosulfate for diuron degradation: Performance and mechanism

“…The according rate constant increased from 6×10 -3 min -1 to 3.6×10 -2 min -1 as catalyst dosage ranged from 0.2 g/L to 0.6 g/L. This is because increasing catalyst dosage provided increasing active sites to activate PMS, yielding more radicals as a12 result. On the contrary, some previous studies reported that with the increase of catalyst dosage, the contaminants removal rate reached a maximum in Fe 3 O 4 activated…”

“…In AOPs, sulfate radical (SO 4 •-) based AOPs have been widely researched in recent decades due to its high redox potential (2.5-3.1 V) and selectivity compared to hydroxyl radical (OH • ) [10,11]. SO 4 •-is usually generated from peroxymonosulfate (PMS) and persulfate (PS) via UV [12], heat [8], or transition metals [13]. Among them, transition metals attracted much attention because of their high efficiency and convenience, but the removal of transition metals (such as Fe 2+ , Co 2+ ) appeared to be a new hard problem to resolve [14], which limits their spread.…”