The degradation of sulfamethazine (SMN) by VUV/UV photo-Fenton (VPF) process was investigated with a mini-fluidic VUV/UV photoreaction system. Compared with the conventional UV photo-Fenton process, the VPF process significantly enhanced the degradation and mineralization of SMN, because the VUV irradiation photolyzed H₂O and accelerated the redox cycle of Fe³⁺/Fe²⁺ to generate more reactive oxygen species (ROS). Initial pH and concentrations of SMN, H₂O₂, Fe³⁺, inorganic anions (NO₃⁻, HCO₃⁻, and Cl⁻), and humic acid all considerably impacted SMN degradation in the VPF process. In particular, the initial SMN concentration significantly affected the absorption distributions of UV and VUV photons in the reaction solution, thus inducing a different reaction mechanism. At a lower SMN concentration (1.8 μM), most of UV and VUV photons were absorbed by Fe³⁺ and H₂O, respectively, so indirect oxidation by ROS mainly accounted for SMN degradation. However, at a higher SMN concentration (90 μM), 89.2% of UV photons and 59.0% of VUV photons were absorbed by SMN, so direct photolysis also played an important role. In addition, HO and HO₂ were identified as the main ROS in the VPF process. This study demonstrates that the VPF process can effectively remove organic micropollutants from water.

中文翻译：

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VUV / UV光-Fenton法加速水中磺胺二甲嘧啶的降解：磺胺二甲嘧啶浓度对反应机理的影响

利用微型流体VUV / UV光反应系统研究了VUV / UV光-Fenton（VPF）工艺对磺胺二甲嘧啶（SMN）的降解。与传统的紫外光Fenton工艺相比，VPF工艺显着增强了SMN的降解和矿化作用，因为VUV照射会光解H ₂ O并加速Fe ³⁺ / Fe ²⁺的氧化还原循环，从而产生更多的活性氧（ ROS）。初始pH和SMN，H的浓度₂ ö ₂，铁³⁺，无机阴离子（NO ₃ ^-，HCO ₃ ^-和Cl ^-）和腐殖酸都在VPF工艺中极大地影响了SMN的降解。特别地，初始SMN浓度显着影响反应溶液中UV和VUV光子的吸收分布，从而引起不同的反应机理。在较低的SMN浓度（1.8μM）下，大多数UV和VUV光子分别被Fe ³⁺和H ₂ O吸收，因此ROS的间接氧化主要是SMN降解的原因。但是，在较高的SMN浓度（90μM）下，SMN吸收了89.2％的UV光子和59.0％的VUV光子，因此直接光解也起了重要作用。另外，HO和HO ₂被确定为VPF过程中的主要ROS。这项研究表明，VPF工艺可以从水中有效去除有机微量污染物。