非晶合金降解偶氮染料的性能研究
發(fā)布時間：2018-09-10 13:45
【摘要】：近期,研究發(fā)現(xiàn)非晶合金能高效降解偶氮染料分子,受到了廣泛的關(guān)注。該發(fā)現(xiàn)為非晶合金作為功能材料的應(yīng)用開辟了新的方向。然而,關(guān)于非晶合金對偶氮染料高效降解機理、非晶合金的成分和表面狀態(tài)等對降解行為的影響規(guī)律及機制等問題的理解尚不深入,影響了適用于高效降解印染廢水的非晶合金成分及工藝的發(fā)展。針對此,本文開展了 Fe基非晶合金、Co基非晶合金和Cu基非晶合金對偶氮染料降解行為及機制的研究,同時研究了 Fe基非晶合金與電化學(xué)方法耦合降解偶氮染料的行為及機制。研究結(jié)果一方面加深了非晶合金高效降解偶氮染料的行為及機制的理解,另一方面對發(fā)展高性能水處理用非晶合金及其實際應(yīng)用具有重要的推動作用。表面氧化的Fe_(78)Si_8B_(14)非晶合金對偶氮染料溶液的脫色過程可以分為兩個階段,且均符合假一級衰減動力學(xué)模型。第一階段主要表現(xiàn)為對染料分子的吸附效應(yīng),第二階段表現(xiàn)為非晶合金對染料分子還原、催化降解過程。脫色速率第二階段優(yōu)于第一階段。這種降解行為主要與表面氧化的Fe_(78)Si_8B_(14)非晶合金在偶氮染料水溶液中的表面組織狀態(tài)演變密切相關(guān)。在偶氮染料水溶液中,Fe基非晶合金的表面氧化膜首先溶解破裂,暴露出新鮮表面,進(jìn)一步被腐蝕,逐漸形成疏松狀表面組織,一方面有利于對染料分子的吸附,另一方面,隨著吸附染料分子的量增多,暴露的新鮮表面能夠充分接觸到染料分子,從而誘發(fā)了還原反應(yīng)、催化降解等過程的發(fā)生。連續(xù)多次重復(fù)降解試驗也驗證了這一點。除首次外,其余各次的脫色過程均為一步反應(yīng),并具有更快的脫色效率。由此可見,表面氧化膜只在一定程度上延緩了脫色進(jìn)程,而對Fe_(78)Si_8B_(14)非晶合金降解偶氮染料的最終效果及長久使用性能影響不大。Co78Si8B14非晶合金具有很好的降解偶氮染料能力,其降解偶氮染料的速率高于相應(yīng)的晶態(tài)合金以及Fe基、Mg基非晶合金,同時表現(xiàn)出較小的質(zhì)量損失。這主要是由于Co0作為電子提供者還原降解染料分子的作用較弱,而Co78Si8B14非晶合金中高度配位不飽和的原子作為催化劑,利用吸附的原子態(tài)氫對染料分子進(jìn)行加氫催化,以及Si、B和Co之間形成局部電偶,電催化水與溶解氧反應(yīng)生成強氧化性的·OH氧化分解偶氮染料起主導(dǎo)作用。這種降解機制使得Co78Si88B14非晶合金降解偶氮染料的適用范圍更寬,對于不同溫度、不同初始濃度、不同pH (3～10)的染料廢水都能實現(xiàn)很好的降解效果,且能多次重復(fù)使用。Cu46Zr445A175Gd2非晶合金也能夠很好地降解偶氮染料,降解反應(yīng)的表觀激活能僅為17 kJ/mol,遠(yuǎn)低于已有非晶合金降解偶氮染料的表觀激活能,說明Cu46Zr44.5A17 5Gd2非晶合金降解偶氮染料時具有高催化活性。此外,Cu46Zr44.5A17.5Gd2非晶合金具有優(yōu)異的耐腐蝕性能,其在降解偶氮染料的過程中幾乎沒有腐蝕損耗以及零價金屬還原偶氮染料的反應(yīng),使得Cu46Zr44 5A175Gd2非晶合金在降解偶氮染料的過程具有良好的穩(wěn)定性,如在重復(fù)循環(huán)使用十次之后,Cu46Zr44.5A17.5Gd2非晶合金處理偶氮染料的降解效率和降解速率依然能夠保持不變。相對于Fe基、Mg基和Co基等非晶合金,Cu46Zr44 5A175Gd2非晶合金降解染料廢水不僅速率快,使用壽命更是大幅度提高,但pH值適用范圍相對較小。電場的施加對于Fe_(78)Si_8B_(14)非晶合金降解偶氮染料具有重要促進(jìn)作用。Fe_(78)Si_8B_(14)非晶合金與電化學(xué)方法聯(lián)用,能夠電催化H2O與O2反應(yīng)生成羥基自由基(·OH),從而快速氧化染料分子,提高降解速率。U=1 V時Fe_(78)Si_8B_(14)非晶合金電化學(xué)的降解偶氮染料的反應(yīng)速率比U=0 V的化學(xué)法快12倍。Fe_(78)Si_8B_(14)非晶合金電化學(xué)降解偶氮染料的電能耗和電極質(zhì)量損失均較小。與形穩(wěn)陽極、硼摻雜金剛石膜電極和炭電極等相比,Fe_(78)Si_8B_(14)非晶合金條帶作為電極電化學(xué)降解染料廢水的單位電能耗降低了 4～6個數(shù)量級,這解決了電化學(xué)處理染料廢水技術(shù)中的一大難題,極大促進(jìn)了電化學(xué)處理廢水技術(shù)的實施。
[Abstract]:Recently, the discovery that amorphous alloys can degrade azo dye molecules efficiently has attracted wide attention. This discovery opens up a new direction for the application of amorphous alloys as functional materials. However, the mechanism of high-efficiency degradation of azo dyes by amorphous alloys, the influence of composition and surface state of amorphous alloys on the degradation behavior and the mechanism are also discussed. Understanding of the problem of fabrication is not thorough, which affects the development of amorphous alloy composition and technology for efficient degradation of printing and dyeing wastewater. In this paper, the degradation behavior and mechanism of azo dyes by Fe-based amorphous alloys, Co-based amorphous alloys and Cu-based amorphous alloys are studied, and the coupling between Fe-based amorphous alloys and electrochemical methods is also studied. Behavior and mechanism of azo dye degradation by combination. The results of this study not only deepen the understanding of the behavior and mechanism of azo dye degradation by amorphous alloys, but also promote the development of amorphous alloys for high performance water treatment and their practical applications. The decolorization process can be divided into two stages, which are in accordance with the pseudo-first-order decay kinetic model. The first stage is mainly the adsorption of dye molecules, the second stage is the reduction of dye molecules by amorphous alloys and the catalytic degradation process. In Azo Dye Aqueous solution, the surface oxide film of Fe-based amorphous alloy first dissolves and breaks down, exposes the fresh surface, further corrodes, and gradually forms loose surface structure. On the one hand, it is beneficial to the adsorption of dye molecules. On the other hand, with the increase of the amount of adsorbed dye molecules, the exposed fresh surface can fully contact the dye molecules, which induces the reduction reaction, catalytic degradation and other processes. It can be seen that the surface oxidation film only delays the decolorization process to a certain extent, but has little effect on the final effect of degradation of azo dyes and long-term performance of Fe_ (78) Si_8B_ (14) amorphous alloy. Co78Si8B14 amorphous alloy has a good ability to degrade azo dyes, and its degradation rate of azo dyes is higher than that of corresponding crystalline alloy. This is mainly due to the weak role of Co0 as an electron provider in reducing and degrading dye molecules, whereas the highly coordinated unsaturated atoms in Co78Si8B14 amorphous alloy act as catalysts for hydrogenation of dye molecules by adsorbed atomic hydrogen, and Si, B and Co. The degradation mechanism makes the amorphous alloy Co78Si88B14 more suitable for the degradation of azo dyes. The dye wastewater with different initial pH (3-10) can be achieved at different temperatures and concentrations. Cu46Zr445A175Gd2 amorphous alloy can also degrade azo dyes well. The apparent activation energy of the degradation reaction is only 17 kJ/mol, which is much lower than the apparent activation energy of the existing amorphous alloy degrading azo dyes. Cu46Zr44.5A17.5Gd2 amorphous alloys have excellent corrosion resistance, almost no corrosion loss and zero-valent metal reduction of azo dyes during the degradation of azo dyes. Cu46Zr44.5A175Gd2 amorphous alloys have good stability in the degradation of azo dyes. For example, Cu46Zr44.5A175Gd2 amorphous alloys can be reused for ten times. Compared with Fe-based, Mg-based and Co-based amorphous alloys, Cu46Zr44 5A175Gd2 amorphous alloys can degrade dye wastewater at a faster rate and a longer service life, but the pH value is relatively small. Fe_ (78) Si_8B_ (14) amorphous alloy can electrocatalyze the reaction of H2O with O2 to form hydroxyl radical (. OH), thus rapidly oxidizing the dye molecule and increasing the degradation rate. The reaction rate is 12 times faster than that of U=0 V chemical method. The energy consumption and electrode mass loss of Fe_ (78) Si_8B_ (14) amorphous alloy for electrochemical degradation of azo dyes are small. Compared with shape stabilized anode, boron doped diamond film electrode and carbon electrode, Fe_ (78) Si_8B_ (14) amorphous alloy strip is used as electrode for electrochemical degradation of dye wastewater. The reduction of 4-6 orders of magnitude has solved a difficult problem in the electrochemical treatment of dye wastewater and greatly promoted the implementation of the electrochemical treatment of wastewater technology.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：X703;TG139.8
本文編號：2234615
[Abstract]:Recently, the discovery that amorphous alloys can degrade azo dye molecules efficiently has attracted wide attention. This discovery opens up a new direction for the application of amorphous alloys as functional materials. However, the mechanism of high-efficiency degradation of azo dyes by amorphous alloys, the influence of composition and surface state of amorphous alloys on the degradation behavior and the mechanism are also discussed. Understanding of the problem of fabrication is not thorough, which affects the development of amorphous alloy composition and technology for efficient degradation of printing and dyeing wastewater. In this paper, the degradation behavior and mechanism of azo dyes by Fe-based amorphous alloys, Co-based amorphous alloys and Cu-based amorphous alloys are studied, and the coupling between Fe-based amorphous alloys and electrochemical methods is also studied. Behavior and mechanism of azo dye degradation by combination. The results of this study not only deepen the understanding of the behavior and mechanism of azo dye degradation by amorphous alloys, but also promote the development of amorphous alloys for high performance water treatment and their practical applications. The decolorization process can be divided into two stages, which are in accordance with the pseudo-first-order decay kinetic model. The first stage is mainly the adsorption of dye molecules, the second stage is the reduction of dye molecules by amorphous alloys and the catalytic degradation process. In Azo Dye Aqueous solution, the surface oxide film of Fe-based amorphous alloy first dissolves and breaks down, exposes the fresh surface, further corrodes, and gradually forms loose surface structure. On the one hand, it is beneficial to the adsorption of dye molecules. On the other hand, with the increase of the amount of adsorbed dye molecules, the exposed fresh surface can fully contact the dye molecules, which induces the reduction reaction, catalytic degradation and other processes. It can be seen that the surface oxidation film only delays the decolorization process to a certain extent, but has little effect on the final effect of degradation of azo dyes and long-term performance of Fe_ (78) Si_8B_ (14) amorphous alloy. Co78Si8B14 amorphous alloy has a good ability to degrade azo dyes, and its degradation rate of azo dyes is higher than that of corresponding crystalline alloy. This is mainly due to the weak role of Co0 as an electron provider in reducing and degrading dye molecules, whereas the highly coordinated unsaturated atoms in Co78Si8B14 amorphous alloy act as catalysts for hydrogenation of dye molecules by adsorbed atomic hydrogen, and Si, B and Co. The degradation mechanism makes the amorphous alloy Co78Si88B14 more suitable for the degradation of azo dyes. The dye wastewater with different initial pH (3-10) can be achieved at different temperatures and concentrations. Cu46Zr445A175Gd2 amorphous alloy can also degrade azo dyes well. The apparent activation energy of the degradation reaction is only 17 kJ/mol, which is much lower than the apparent activation energy of the existing amorphous alloy degrading azo dyes. Cu46Zr44.5A17.5Gd2 amorphous alloys have excellent corrosion resistance, almost no corrosion loss and zero-valent metal reduction of azo dyes during the degradation of azo dyes. Cu46Zr44.5A175Gd2 amorphous alloys have good stability in the degradation of azo dyes. For example, Cu46Zr44.5A175Gd2 amorphous alloys can be reused for ten times. Compared with Fe-based, Mg-based and Co-based amorphous alloys, Cu46Zr44 5A175Gd2 amorphous alloys can degrade dye wastewater at a faster rate and a longer service life, but the pH value is relatively small. Fe_ (78) Si_8B_ (14) amorphous alloy can electrocatalyze the reaction of H2O with O2 to form hydroxyl radical (. OH), thus rapidly oxidizing the dye molecule and increasing the degradation rate. The reaction rate is 12 times faster than that of U=0 V chemical method. The energy consumption and electrode mass loss of Fe_ (78) Si_8B_ (14) amorphous alloy for electrochemical degradation of azo dyes are small. Compared with shape stabilized anode, boron doped diamond film electrode and carbon electrode, Fe_ (78) Si_8B_ (14) amorphous alloy strip is used as electrode for electrochemical degradation of dye wastewater. The reduction of 4-6 orders of magnitude has solved a difficult problem in the electrochemical treatment of dye wastewater and greatly promoted the implementation of the electrochemical treatment of wastewater technology.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：X703;TG139.8
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