Abstract The vortex cavitation technology shows a great development potential for antibiotic wastewater treatment. We have designed a novel swirling vortex cavitator for tetracycline degradation in aqueous solution. By Computational Fluid Dynamics (CFD) simulation using ANSYS CFX flow field calculation software, it was found that the vortex cavitator could form a low-pressure area far lower than the saturated vapor pressure at experimental temperature, resulting in generation of obvious vortex cavitation effect, which also proved by the concentration of hydroxyl radical of 4.58 μmol/L measured by methylene blue method. Moreover, the tetracycline degradation process may be mainly caused by the oxidation of hydroxyl radicals. The batch experiments results showed when the degradation time was 30 min, the vortex cavitator had a good degradation ability of tetracycline in pH range of 5.0–9.0. The degradation efficiency of 2.0 mg/L tetracycline solution was 76.45% within 50 min at pH 7.0. The possible intermediate products of tetracycline were determined by HPLC-MS Spectrometry. A series of reactions including hydroxylation, decarbonylation and C–N bond cleavage, ring-opening, and removing two methyl groups in the carbon atom ring, occur during the degradation.

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旋涡空化器的CFD模拟及其在水溶液中四环素的降解性能和途径

摘要 涡流空化技术在抗生素废水处理中显示出巨大的发展潜力。我们设计了一种新型涡旋空化器，用于在水溶液中降解四环素。通过使用ANSYS CFX流场计算软件进行计算流体动力学（CFD）模拟，发现涡流空化器在实验温度下可以形成远低于饱和蒸汽压的低压区，从而产生明显的涡流空化效应，亚甲蓝法测得的羟基自由基浓度为4.58 μmol/L也证明了这一点。此外，四环素降解过程可能主要是由羟基自由基的氧化引起的。批量实验结果表明，当降解时间为 30 min 时，涡旋空化器在pH 5.0~9.0 范围内对四环素具有良好的降解能力。在 pH 7.0 条件下，2.0 mg/L 四环素溶液在 50 分钟内的降解效率为 76.45%。四环素可能的中间产物通过HPLC-MS光谱法确定。在降解过程中会发生一系列反应，包括羟基化、脱羰和 C-N 键断裂、开环和去除碳原子环中的两个甲基。