In this study, a modified Fenton system using calcium peroxide (CaO₂) powder, as an effective source of hydrogen peroxide (H₂O₂), for the degradation of sulfamethoxazole (SMX) in aqueous solution was investigated. Our results indicated that degradation of SMX in Fe(II)-EDTA catalyzed CaO₂ system was readily more efficient than in Fe(II) catalyzed CaO₂ system. The SMX degradation efficiency was found maximum at pH 6.0 and SMX degradation was suppressed as the initial solution pH was increased. Nevertheless overall removal efficiency in this system was favorable near to neutral pH. In addition, it was observed that the higher bicarbonates (HCO₃⁻) contents had a considerable scavenging ability to SMX degradation while low concentration exhibited auspicious role. The presence of chlorides (Cl⁻), nitrates (NO₃⁻), sulfates (SO₄²⁻), and humic acid (HA) could improve SMX removal in this Fenton-like system. Furthermore, chemical probe and radical scavenging activity confirmed the formation of hydroxyl (HO) and superoxide (O₂⁻) radicals, and also described that the SMX degradation was predominantly due to the HO-induced oxidative destruction. Electron paramagnetic resonance (EPR) studies for different systems, different pH values and different reaction times were carried out to determine the HO radical intensities. EPR results showed that HO intensities were higher in Fe(II)-EDTA catalyzed CaO₂ system, at pH 6.0 and at 90 s reaction time, respectively. Intermediate products of SMX were identified and possible mechanism of SMX degradation was suggested. In conclusion, this work provided comprehensive knowledge for the use of Fe(II)-EDTA catalyzed CaO₂ system for remediation of SMX contaminated sites.

在这项研究中，研究了一种改良的Fenton系统，该系统使用过氧化钙（CaO ₂）粉作为过氧化氢（H ₂ O ₂）的有效来源，用于降解水溶液中的磺胺甲恶唑（SMX）。我们的结果表明，SMX在Fe（II）-EDTA催化的CaO ₂系统中的降解比在Fe（II）的CaO ₂系统中的降解更容易。发现SMX降解效率在pH 6.0时最大，并且随着初始溶液pH值的增加，SMX降解受到抑制。然而，在接近中性pH的情况下，该系统的总体去除效率良好。此外，可以观察到更高的碳酸氢盐（HCO ₃ ^-）内容物对SMX降解具有相当大的清除能力，而低浓度则表现出吉祥的作用。氯化物（CL的存在^- ，硝酸盐（NO）₃ ^- ），硫酸根（SO ₄ ^2- ），和腐殖酸（HA）可以改善在这类芬顿系统SMX去除。此外，化学探针和自由基清除活性证实羟基的形成（HO ）和超（O ₂ ^- ）基团，并且还描述了SMX降解主要归因于HO诱导氧化破坏。进行了针对不同系统，不同pH值和不同反应时间的电子顺磁共振（EPR）研究，以确定HO自由基强度。EPR结果表明，Fe（II）-EDTA催化的CaO ₂体系在pH 6.0和90 s的反应时间分别具有较高的HO强度。鉴定了SMX的中间产物，并提出了SMX降解的可能机理。总之，这项工作为使用Fe（II）-EDTA催化的CaO ₂系统修复SMX污染部位提供了全面的知识。