本文關(guān)鍵詞：錳氧八面體分子篩活化過(guò)一硫酸氫鹽降解酸性橙7的研究　出處：《武漢紡織大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 高級(jí)氧化 錳氧八面體分子篩 酸性橙7 過(guò)硫酸氫鹽 四氧化三鐵

【摘要】：氧化錳八面體分子篩(OMS-2)因晶格中存在Mn~(2+)、Mn~(3+)和Mn~(4+),具有溫和的表面酸性和良好的氧化還原性,成為科研工作者一個(gè)新的研究熱點(diǎn)。基于硫酸根自由基的新型高級(jí)氧化技術(shù)作為一項(xiàng)綠色、經(jīng)濟(jì)、簡(jiǎn)單、應(yīng)用廣的水處理技術(shù),但目前還存在成本高、催化劑效率較低和金屬組分易流失等缺陷。因此探索OMS-2作為新型催化劑用于活化過(guò)硫酸鹽降解廢水具有重要意義。本論文分別利用加熱回流法和無(wú)溶劑法制備了OMS-2和磁性Fe_3O_4@OMS-2催化劑,采用X射線(xiàn)衍射、傅里葉變換紅外光譜、掃描電子顯微鏡、N2吸附/脫附等溫線(xiàn)、X射線(xiàn)光電子能譜(XPS)和電子順磁共振(ESR)等技術(shù)對(duì)催化劑進(jìn)行表征分析來(lái)確定其結(jié)構(gòu)。再以過(guò)一硫酸氫鹽(PMS)為氧化劑,輔以可見(jiàn)光(Vis)的作用,構(gòu)建了OMS-2/PMS、OMS-2/PMS/Vis和Fe_3O_4@OMS-2/PMS三種催化體系,并分別研究了這些體系降解酸性橙7(AO7)的效果、降解中間產(chǎn)物、動(dòng)力學(xué)、催化劑穩(wěn)定性以及反應(yīng)機(jī)理,得出以下主要結(jié)論:(1)在OMS-2/PMS催化體系中,OMS-2和PMS對(duì)于染料廢水的降解缺一不可。該體系可在15min內(nèi)可完全去除AO7和其他染料。增大染料濃度、催化劑量和PMS濃度可促進(jìn)染料的降解;但隨著溶液p H值增大去除效率降低。五次重復(fù)后的OMS-2依然具有很好的催化性能。自由基抑制性實(shí)驗(yàn)證明催化劑活化PMS時(shí)產(chǎn)生的硫酸根自由基為該體系的主要活性物種。XPS和ESR結(jié)果表示催化機(jī)理可能涉及到在PMS中Mn(Ⅳ)離子的還原和Mn(Ⅲ)離子的氧化�；陔妵婌F質(zhì)譜的分析還提出了OMS-2/PMS體系降解AO7的降解途徑。(2)與OMS-2/PMS體系相比,OMS/PMS/Vis體系具有更高的AO7和中間產(chǎn)物的降解率。ESR和XPS分析可得,OMS-2/PMS/Vis體系的催化過(guò)程涉及Mn(Ⅳ)/Mn(Ⅲ)和Mn(Ⅲ)/Mn(II)的氧化還原;而OMS-2/PMS體系僅發(fā)生在Mn(Ⅳ)和Mn(Ⅲ)之間。(3)通過(guò)無(wú)溶劑法將OMS-2負(fù)載于Fe_3O_4上生成核殼式磁性納米催化材料具有251m2/g的高表面積和高順磁性,同時(shí)表現(xiàn)出活化PMS降解有機(jī)染料的高催化活性。使用外部磁場(chǎng)分離反應(yīng)后的催化劑后具有相當(dāng)高的活性,重復(fù)使用十次去除率依然可以達(dá)到85%,是一種高效,穩(wěn)定性強(qiáng),回收利用率高的催化材料。
[Abstract]:Manganese oxide octahedron molecular sieve (OMS-2) has mild surface acidity and good redox properties due to the presence of Mn~(2 and Mn~(4 in the crystal lattice. New advanced oxidation technology based on sulfate radical is a green, economical, simple and widely used water treatment technology, but it still has high cost. Therefore, it is important to explore OMS-2 as a new type of catalyst for activated persulfate degradation of wastewater. In this paper, heating reflux method and solvent-free method are used respectively. OMS-2 and magnetic Fe_3O_4@OMS-2 catalysts were prepared. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and N2 adsorption / desorption isotherms were used. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (ESR) were used to characterize the catalyst to determine its structure. Three catalytic systems, OMS-2 / PMS-2pPMS-Vis and Fe_3O_4@OMS-2/PMS, were constructed. The degradation effect, degradation intermediate product, kinetics, catalyst stability and reaction mechanism of these systems were studied. The main conclusions are as follows: 1) in OMS-2/PMS catalytic system. OMS-2 and PMS are indispensable for the degradation of dye wastewater. The system can completely remove AO7 and other dyes within 15 minutes and increase the dye concentration. The amount of catalyst and the concentration of PMS can promote the degradation of dyes. But with solution p, When H value was increased, the removal efficiency was decreased. After five times repeated, OMS-2 still had good catalytic performance. The experiment of free radical inhibition proved that the sulfate radical produced when the catalyst activated PMS was the main activity of the system. The results of sex species. XPS and ESR indicate that the catalytic mechanism may be related to Mn( 2) in PMS. 鈪，

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