Abstract
Sulfamethoxazole (SMZ), sulfathiazole (STZ) and sulfamethazine (SMT) are typical sulfonamides, which are widespread in aqueous environments and have aroused great concern in recent years. In this study, the photochemical oxidation of SMZ, STZ and SMT in their mixed solution using UV/H2O2 process was innovatively investigated. The result showed that the sulfonamides could be completely decomposed in the UV/H2O2 system, and each contaminant in the co-existence system fitted the pseudo-first-order kinetic model. The removal of sulfonamides was influenced by the initial concentration of the mixed solution, the intensity of UV light irradiation, the dosage of H2O2 and the initial pH of the solution. The increase of UV light intensity and H2O2 dosage substantially enhanced the decomposition efficiency, while a higher initial concentration of mixed solution heavily suppressed the decomposition rate. The decomposition of SMZ and SMT during the UV/H2O2 process was favorable under neutral and acidic conditions. Moreover, the generated intermediates of SMZ, STZ and SMT during the UV/H2O2 process were identified in depth, and a corresponding degradation pathway was proposed.
Highlights
The ubiquitous occurrence of pharmaceutical compounds as well as their conversion products and metabolites have been recognized as a rising environmental issue of global concern because they are widely and increasingly used for human and veterinary therapeutic purposes, and are constantly released into the aqueous environment
The photolysis, photocatalysis, H2 O2 -enhanced photolysis, ozonation, electrochemical oxidation and Fenton are frequently studied advanced oxidation processes (AOPs) [1,6,11,12,13]. Among these AOPs, the UV/H2 O2 process consists of a combination of two well-known processes, direct UV photolysis and peroxidation, that lead to the generation of hydroxyl radicals, which make this process simpler and more effective for the removal of organic contaminants compared to peroxidation or photolysis respectively [14,15]
The collected water samples during the experiment were directly used for the determination of residual target compounds by high-performance liquid chromatography (HPLC) according to the above conditions
Summary
The ubiquitous occurrence of pharmaceutical compounds as well as their conversion products and metabolites have been recognized as a rising environmental issue of global concern because they are widely and increasingly used for human and veterinary therapeutic purposes, and are constantly released into the aqueous environment. The detection of sulfonamides in the treated drinking water and wastewater treatment plant effluent indicates that conventional water and wastewater treatment processes cannot effectively eliminate sulfonamides For these aforementioned reasons, it is highly desired to develop reliable water treatment methods that can efficiently remove sulfonamides at a trace level, especially in China. The photolysis, photocatalysis, H2 O2 -enhanced photolysis, ozonation, electrochemical oxidation and Fenton are frequently studied AOPs [1,6,11,12,13] Among these AOPs, the UV/H2 O2 process consists of a combination of two well-known processes, direct UV photolysis and peroxidation, that lead to the generation of hydroxyl radicals, which make this process simpler and more effective for the removal of organic contaminants compared to peroxidation or photolysis respectively [14,15]. Based on the identification of the generated intermediates and the proposing of the corresponding degradation pathway, the feasibility of using the UV/H2 O2 process for the degradation of sulfonamides was demonstrated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
