Abstract:

Mn₃O₄-MnOOH binary composite material was prepared by means of partial oxidation of Mn（OH）₂ with H₂O₂ under alkaline condition and applied as an activator of peroxymonosulfate（PMS） for catalytic oxidation degradation of refractory dye Rhodamine B.The physical and chemical properties of the material were characterized by X-ray diffraction （XRD），X-ray photoelectron spectroscopy（XPS），scanning electron microscopy（SEM），transmission electron microscopy（TEM） and other means. It was determined that the material was a binary nanosheet with MnOOH-coated Mn₃O₄ core-shell structure. Through investigating the degradation efficiency of Rhodamine B in different catalytic systems，it could be concluded that Mn₃O₄-MnOOH composites had better catalytic efficiency than single manganese oxide. On this basis，the effects of initial pH of solution，dosage of catalyst，dosage of KHSO₅，pollutant concentration and other factors on dye degradation were further investigated，and the appropriate reaction conditions were determined as follows：pH 4，0.1 g/L of mass concentration of catalyst，0.325 0 mmol/L of concentration of KHSO₅，and 50 mg/L of initial mass concentration of pollutant. Under these conditions， after 30 min of reaction， the removal rate of Rhodamine B was 92.8%. The free radical quenching experiment and ESR detection showed that the active oxygen containing groups in the reaction system were ¹O₂，SO₄^·- and ·OH，of which ¹O₂ and SO₄^·- played a major role in the degradation of Rhodamine B. The material stability experiment showed that Mn₃O₄-MnOOH composite had good stability and reusability，and had certain application prospects in industrial wastewater treatment.

Key words: binary composite material, catalytic, potassium peroxymonosulfate, advanced oxidation process

摘要：

在碱性条件下，使用H₂O₂部分氧化Mn（OH）₂制备了Mn₃O₄-MnOOH复合材料，并将其作为过硫酸氢钾活化剂用于催化氧化降解水中难降解染料罗丹明B。采用X射线衍射仪（XRD）、X射线光电子能谱（XPS）、扫描电镜（SEM）、透射电镜（TEM）等多种手段表征了材料的物理化学性质，确定了其为内部Mn₃O₄、外部MnOOH的二元纳米片状核壳式结构。通过考察不同催化体系下罗丹明B的降解效果可得Mn₃O₄-MnOOH复合材料具有比单一锰氧化物更好的催化效能。在此基础上，进一步考察溶液初始pH、催化剂投加量、KHSO₅投加量、污染物浓度等因素对染料降解的影响，确定了适宜的反应条件，即pH为4，催化剂投加质量浓度为0.1 g/L，KHSO₅投加浓度为0.325 0 mmol/L，污染物初始质量浓度为50 mg/L，该条件下，反应30 min后，罗丹明B去除率为92.8%。自由基猝灭实验和ESR检测表明反应体系中的活性含氧基团有¹O₂、SO₄^·-、·OH，其中¹O₂和SO₄^·-对罗丹明B的降解起主要作用。Mn₃O₄-MnOOH复合材料具有良好的稳定性和可重复利用性，在工业废水处理中有一定的应用前景。

关键词: 二元复合材料, 催化, 过硫酸氢钾, 高级氧化

CLC Number: 

• X703.1