Department of Chemical and Materials Engineering, National Yunlin University of Science & Technology, Yunlin 640, Taiwan, ROC.
Department of Chemical and Materials Engineering, National Yunlin University of Science & Technology, Yunlin 640, Taiwan, ROC.
Ultrason Sonochem. 2019 Mar;51:129-137. doi: 10.1016/j.ultsonch.2018.10.035. Epub 2018 Oct 26.
Oxidative degradation of dinitrotoluenes (DNTs) in industrial wastewater was conducted by sono-activated persulfate process assisted with electrolytes. Experiments were carried out to elucidate the influence of various operating parameters on the sonolytic behavior, such as species and concentrations of electrolytes, ultrasonic power intensity, reaction temperature, dosage of oxygen and persulfate anions. The outcomes indicate that sulfate radicals serve as main oxidants in the sono-activated persulfate process, wherein MgSO electrolyte obviously inhibits microbubble coalescence, leading to enhancement of cavitation strength and DNTs removal percentage. On addition of electrolytes, the increment of DNTs removal percentages was proportional to ionic strength of electrolytes. According to the results obtained from gas chromatograph-mass spectrometer (GC-MS), it is postulated that DNTs initially undergo denitration pathway with cleavage of nitro group into o-mononitrotoluene (MNT) or oxidation of methyl group followed with decarboxylation procedure into 1,3-dinitrobenzene (DNB), respectively. Due to electrolytes observed commonly in wastewater, the sono-activated persulfate process coupled with electrolytes is potentially applied to dispose wastewater effluent from toluene nitration processes.
采用声激活过硫酸盐工艺，并辅以电解质，对工业废水中的二硝基甲苯（DNTs）进行了氧化降解研究。进行了实验，以阐明各种操作参数对超声行为的影响，例如电解质的种类和浓度、超声功率强度、反应温度、氧气和过硫酸盐阴离子的用量。结果表明，在声激活过硫酸盐工艺中，硫酸根自由基作为主要氧化剂，其中 MgSO4 电解质明显抑制了微气泡的聚并，从而增强了空化强度和 DNTs 的去除率。添加电解质后，DNTs 去除率的增加与电解质的离子强度成正比。根据气相色谱-质谱联用仪（GC-MS）的结果，推测 DNTs 首先经历脱硝基途径，硝基基团断裂成邻硝基甲苯（MNT）或氧化甲基基团，随后进行脱羧反应生成 1,3-二硝基苯（DNB）。由于废水中常见的电解质，因此声激活过硫酸盐工艺与电解质结合，有望用于处理甲苯硝化工艺的废水。
