二氧化锰活化过硫酸盐降解染料废水的研究

发布时间：2018-01-13 12:58

  本文关键词：二氧化锰活化过硫酸盐降解染料废水的研究　出处：《上海应用技术大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 硫酸根自由基 过一硫酸盐 二氧化锰 染料 降解 机理

【摘要】：染料废水是典型的难降解工业废水之一,具有COD高、色度高、毒性大、可生化性差等特点。传统的水污染处理技术如吸附法、絮凝沉淀法、生物降解法等难以适应新型染料废水的处理。近年来,发展起来的以硫酸根自由基(SO_4~-·)为主要活性物种的非均相高级氧化技术引起了研究者越来越多的关注。基于SO_4~-·的非均相高级氧化技术具有以下优点：(1)氧化剂为固体颗粒,稳定性远大于H_2O_2和O_3；(2)氧化剂活化产生SO_4~-·时受pH影响小；(3)SO_4~-·的寿命长,可极大地提高有机污染物的降解效率。Mn02是一种常见的过渡金属氧化物,其晶型结构的多样性使其具有优良的物理化学性能,被广泛用作分子筛、氧化剂、催化剂、电池材料和传感器材料等。因此,本论文选用MnO_2作为非均相催化材料,活化过一硫酸盐(PMS)以产生SO_4~-·,研究基于SO_4~-·的非均相高级氧化技术降解不同结构类型的有机染料的动力学与机理过程。主要研究结果如下：(1)采用水热法制备了一种Mn02,对所制备样品进行X射线衍射(X-ray diffraction, XRD)、扫描电镜(Scanning electron microscope, SEM)、透射电镜(Transmission electron microscope, TEM)、比表面积(Specific surface area, SSA)分析,其中SSA采用BET吸附理论计算。结果表明,所制备的Mn02为50-100 nnn的纳米线Mn02;其比表面积约为228.7 m2/g。(2)利用MnO_2/PMS体系降解三苯甲烷染料,以孔雀石绿作为代表污染物。研究结果表明,MnO_2/PMS体系降解孔雀石绿的过程呈准一级反应动力学特点。PMS浓度、MnO_2投加量增加及温度的升高均可提高MnO_2/PMS体系对孔雀石绿的降解效率。此外,根据阿伦尼乌斯方程计算出MnO_2/PMS体系降解孔雀石绿的活化能为47.3 kJ/mol。重复性实验说明,MnO_2催化剂活性稳定,可重复利用。采用紫外可见分光光度计(UV-Vis)分析降解过程中孔雀石绿的光谱变化,采用气相色谱-质谱联用仪(GC-MS)分析了孔雀石绿的降解中间产物,进而分析了孔雀石绿的降解机理。(3)利用MnO_2/PMS体系降解咕吨染料,以罗丹明B作为代表污染物。研究结果表明,MnO_2/PMS体系降解罗丹明B的过程呈准一级反应动力学特点。PMS浓度和Mn02投加量均与罗丹明B降解反应速率常数呈线性关系。MnO_2/PMS体系不仅能快速降解罗丹明B,还能将其有效矿化。采用UV-Vis及GC-MS技术分析了罗丹明B及其降解中间产物的变化,相关机理也进行了探索。(4)采用乙醇(EtOH)和叔丁醇(TBA)进行自由基捕获实验,研究了MnO_2/PMS体系降解孔雀石绿和罗丹明B过程中的不同自由基产生情况,发现硫酸根自由基在MnO_2/PMS体系降解孔雀石绿和罗丹明B具有重要作用,进而分析了MnO_2活化PMS的机理。
[Abstract]:Dye wastewater is one of the typical refractory industrial wastewater with high COD, high chroma, high toxicity and poor biodegradability. Traditional water pollution treatment techniques such as adsorption method, flocculation precipitation method. Biodegradation is difficult to adapt to the treatment of new dye wastewater in recent years. Developed with sulphate radical (SO4S). The heterogeneous advanced oxidation technology for the main active species has attracted more and more attention. The heterogeneous advanced oxidation technology based on SO4- 路has the following advantages: 1) the oxidant is a solid particle. The stability is much greater than that of H2O2 and OSP; (2) when oxidizing agent activates to produce SO4- 路, pH has little effect on it; It is a common transition metal oxide that the degradation efficiency of organic pollutants can be greatly improved because of its long life. It is widely used as molecular sieves, oxidants, catalysts, battery materials and sensor materials for its excellent physical and chemical properties due to the diversity of crystal structure. In this paper, MnO_2 was used as heterogeneous catalytic material to activate PMSs to produce SO4- 路. The kinetics and mechanism of degradation of organic dyes with different structural types by heterogeneous advanced oxidation technology based on SOS _ 4 ~ (- 路) were studied. The main results are as follows: (1). A kind of Mn02 was prepared by hydrothermal method. X-ray diffraction (XRD) was performed on the prepared samples. Scanning electron microscope (SEM). Transmission electron microscopes (TM). The specific surface area was analyzed by specific surface area (SSAs), in which SSA was calculated by BET adsorption theory. The nanowires Mn02 with Mn02 of 50-100 nnn were prepared. Its specific surface area is about 228.7 m ~ (2 / g 路g 路m ~ (-2))) triphenylmethane dyes were degraded by MnO_2/PMS system and malachite green was used as the representative pollutant. The degradation of malachite green in MnO_2/PMS system was characterized by quasi-first-order reaction kinetics. The degradation efficiency of malachite green could be improved by increasing the dosage of MnO_2 and increasing the temperature. In addition, the degradation efficiency of malachite green could be improved by MnO_2/PMS system. According to Arrhenius equation, the activation energy of malachite green degradation in MnO_2/PMS system was calculated to be 47.3 KJ / mol 路mol. The repeatability experiment showed that the activity of the catalyst was stable. The spectral changes of malachite green during degradation were analyzed by UV-Visspectrophotometer. The degradation intermediates of malachite green were analyzed by gas chromatography-mass spectrometry (GC-MS). Furthermore, the degradation mechanism of malachite green was analyzed. The MnO_2/PMS system was used to degrade goo ton dyes, and Rhodamine B was used as the representative pollutant. The results showed that the degradation mechanism of malachite green was better than that of malachite green. The degradation of Rhodamine B in MnO_2/PMS system showed quasi-first-order kinetic characteristics. Both the concentration of PMS and the dosage of Mn02 were linearly related to the degradation rate constant of Rhodamine B. MNO _ 2. Not only can Rhodamine B be degraded rapidly by PMS system. UV-Vis and GC-MS techniques were used to analyze the changes of Rhodamine B and its degradation intermediates. The related mechanism was also explored. (4) the free radical capture experiments were carried out by using EtOH (ethanol) and TBA (tert-butanol). The production of different free radicals in the degradation of malachite green and Rhodamine B by MnO_2/PMS system was studied. It is found that sulfate radical plays an important role in the degradation of malachite green and Rhodamine B in MnO_2/PMS system. The mechanism of PMS activation by MnO_2 is analyzed.
【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X788;TQ137.12
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本文编号：1418919