溶解性有機(jī)質(zhì)對羥基自由基氧化降解有機(jī)污染物的影響
發(fā)布時(shí)間：2018-08-25 13:09
【摘要】：溶解性有機(jī)質(zhì)(DOM)是環(huán)境中普遍存在的一類結(jié)構(gòu)組分復(fù)雜的混合有機(jī)質(zhì),其官能團(tuán)種類豐富,能夠通過多種機(jī)制與環(huán)境中的有機(jī)污染物(OPs)發(fā)生相互作用,改變污染物環(huán)境歸趨。由于DOM本身既可以與自由基反應(yīng),又可能通過結(jié)合作用影響OPs在水中的形態(tài),從而影響OPs與自由基的反應(yīng)。羥基自由基(·O功是一種氧化能力極強(qiáng)的自由基,不僅在自然界中廣泛存在,而且經(jīng)常被用在高級(jí)氧化體系中去除OPs。本研究通過光照H2O2產(chǎn)生-OH,首先考察了不同來源和結(jié)構(gòu)的DOM與-OH的反應(yīng)能力,并進(jìn)一步研究了DOM對一系列受到廣泛關(guān)注、在環(huán)境中經(jīng)常檢出的OPs與·OH的反應(yīng)的影響。本研究的結(jié)果與發(fā)現(xiàn),可以為揭示自然水環(huán)境中DOM對·OH與OPs反應(yīng)的影響及機(jī)制提供理論依據(jù),也可以為以-OH為基礎(chǔ)的高級(jí)氧化體系的設(shè)計(jì)提供參考。采用總有機(jī)碳分析儀、紫外-可見吸收光譜以及熒光激發(fā)-發(fā)射光譜(EEMs)對5種不同來源DOM與·OH的反應(yīng)過程進(jìn)行了表征,以考察DOM來源和類別對其與-OH反應(yīng)的影響。結(jié)果表明,不同來源DOM與·OH的反應(yīng)能力存在顯著差異,陸源DOM比水源DOM表現(xiàn)出更強(qiáng)的反應(yīng)能力。DOM與·OH的反應(yīng)表現(xiàn)為準(zhǔn)一級(jí)動(dòng)力學(xué),以DOC變化表征的礦化速率常數(shù)kDOC與DOM的芳香碳/脂肪碳(Caro/Cali)有較好的相關(guān)性,說明芳香性碳對DOM與OH的反應(yīng)具有重要貢獻(xiàn)。以光吸收參數(shù)Absave表征的衰減速率常數(shù)與kDOC也表現(xiàn)出良好的相關(guān)性。因來源與類別的差異,不同DOM不僅初始的三維熒光光譜EEMs)存在差別,而且·OH氧化過程中EEMs的變化也表現(xiàn)出顯著的不同。本研究選取了9種不同類別和性質(zhì)的OPs,考察了DOM對其與·OH反應(yīng)的影響。研究發(fā)現(xiàn),DOM存在會(huì)顯著抑制-OH對OPs氧化的準(zhǔn)一級(jí)速率常數(shù)(k'1OH),k'1OH被抑制高達(dá)62%-91%。對于具有較強(qiáng)疏水性的OPs, DOM還會(huì)顯著影響其與·OH的二級(jí)反應(yīng)速率常數(shù)(k2OH)。同一種腐殖酸LHA對7種OPs的k20H抑制程度與OPs的疏水性(logKOW)呈正相關(guān)。logKOW一般與DOM與OPs的結(jié)合常數(shù)(logKDOC)具有很好的相關(guān)性,說明DOM結(jié)合作用對·OH氧化OPs反應(yīng)存在重要影響。不同種類DOM對疏水性有機(jī)物(HOCs)與·OH反應(yīng)的影響不同。隨著DOM濃度增加,HOCs的DOM結(jié)合態(tài)比例相對增多,抑制效應(yīng)增強(qiáng)。不同H2O2濃度下,DOM對·OH與多環(huán)芳烴芘、菲反應(yīng)的k'1OH的抑制程度沒有顯著差異。
[Abstract]:Dissolved organic matter (DOM) is a kind of mixed organic matter with complex structural components in the environment. Its functional groups are abundant and can change the environmental trend of pollutants by interacting with (OPs), an organic pollutant in the environment, through a variety of mechanisms. Because DOM itself can react with free radical and possibly affect the form of OPs in water by binding effect, thus affect the reaction of OPs with free radical. Hydroxyl radical (O work) is a kind of radical with strong oxidation ability. It not only exists widely in nature, but also is often used to remove OPs. in advanced oxidation system. In this study, H2O2 was used to produce -OH. Firstly, the reaction ability of DOM from different sources and structures with -OH was investigated, and the effect of DOM on a series of reactions between OPs and OH, which were widely concerned and frequently detected in the environment, was studied. The results and findings of this study can provide theoretical basis for revealing the effect and mechanism of DOM on the reaction between OH and OPs in natural water environment, and can also provide a reference for the design of advanced oxidation system based on -OH. The reaction process of DOM with OH from five different sources was characterized by total organic carbon analyzer, UV-Vis absorption spectrum and fluorescence excitation emission spectroscopy (EEMs) to investigate the effect of the source and type of DOM on the reaction with -OH. The results showed that there was significant difference in the reaction ability between DOM and OH from different sources, and the reaction ability of terrestrial DOM was stronger than that of source DOM. Dom and OH showed quasi-first-order kinetics. The mineralization rate constant kDOC, which is characterized by the change of DOC, has a good correlation with the aromatic carbon / fatty carbon (Caro/Cali) of DOM, which indicates that aromatic carbon plays an important role in the reaction between DOM and OH. The attenuation rate constant characterized by optical absorption parameter (Absave) also showed a good correlation with kDOC. Because of the difference of source and category, not only the initial three dimensional fluorescence spectra (EEMs) of different DOM are different, but also the changes of EEMs in the process of OH oxidation are obviously different. In this study, nine different types and properties of OPs, were selected to investigate the effect of DOM on the reaction with OH. It is found that the presence of Dom can significantly inhibit the quasi-first-order rate constant (k'1OH) of the oxidation of OPs by -OH up to 62-91. The second order reaction rate constant (k2OH) of OPs, DOM with strong hydrophobicity was also significantly affected. The degree of inhibition of k20H of seven OPs by the same humic acid LHA was positively correlated with the hydrophobic (logKOW) of OPs. LogKOW generally had a good correlation with the binding constant (logKDOC) of DOM and OPs, indicating that DOM binding has an important effect on OH oxidative OPs reaction. Different kinds of DOM have different effects on the reaction of hydrophobic organic compounds (HOCs) with OH. With the increase of DOM concentration, the proportion of DOM binding state of HOCs increased relatively, and the inhibitory effect was enhanced. There was no significant difference in the inhibition of k'1OH between OH and polycyclic aromatic hydrocarbons pyrene and phenanthrene at different concentrations of H2O2.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X505
本文編號(hào)：2202977
[Abstract]:Dissolved organic matter (DOM) is a kind of mixed organic matter with complex structural components in the environment. Its functional groups are abundant and can change the environmental trend of pollutants by interacting with (OPs), an organic pollutant in the environment, through a variety of mechanisms. Because DOM itself can react with free radical and possibly affect the form of OPs in water by binding effect, thus affect the reaction of OPs with free radical. Hydroxyl radical (O work) is a kind of radical with strong oxidation ability. It not only exists widely in nature, but also is often used to remove OPs. in advanced oxidation system. In this study, H2O2 was used to produce -OH. Firstly, the reaction ability of DOM from different sources and structures with -OH was investigated, and the effect of DOM on a series of reactions between OPs and OH, which were widely concerned and frequently detected in the environment, was studied. The results and findings of this study can provide theoretical basis for revealing the effect and mechanism of DOM on the reaction between OH and OPs in natural water environment, and can also provide a reference for the design of advanced oxidation system based on -OH. The reaction process of DOM with OH from five different sources was characterized by total organic carbon analyzer, UV-Vis absorption spectrum and fluorescence excitation emission spectroscopy (EEMs) to investigate the effect of the source and type of DOM on the reaction with -OH. The results showed that there was significant difference in the reaction ability between DOM and OH from different sources, and the reaction ability of terrestrial DOM was stronger than that of source DOM. Dom and OH showed quasi-first-order kinetics. The mineralization rate constant kDOC, which is characterized by the change of DOC, has a good correlation with the aromatic carbon / fatty carbon (Caro/Cali) of DOM, which indicates that aromatic carbon plays an important role in the reaction between DOM and OH. The attenuation rate constant characterized by optical absorption parameter (Absave) also showed a good correlation with kDOC. Because of the difference of source and category, not only the initial three dimensional fluorescence spectra (EEMs) of different DOM are different, but also the changes of EEMs in the process of OH oxidation are obviously different. In this study, nine different types and properties of OPs, were selected to investigate the effect of DOM on the reaction with OH. It is found that the presence of Dom can significantly inhibit the quasi-first-order rate constant (k'1OH) of the oxidation of OPs by -OH up to 62-91. The second order reaction rate constant (k2OH) of OPs, DOM with strong hydrophobicity was also significantly affected. The degree of inhibition of k20H of seven OPs by the same humic acid LHA was positively correlated with the hydrophobic (logKOW) of OPs. LogKOW generally had a good correlation with the binding constant (logKDOC) of DOM and OPs, indicating that DOM binding has an important effect on OH oxidative OPs reaction. Different kinds of DOM have different effects on the reaction of hydrophobic organic compounds (HOCs) with OH. With the increase of DOM concentration, the proportion of DOM binding state of HOCs increased relatively, and the inhibitory effect was enhanced. There was no significant difference in the inhibition of k'1OH between OH and polycyclic aromatic hydrocarbons pyrene and phenanthrene at different concentrations of H2O2.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X505
【參考文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前1條
1 王曉晨;溶解性有機(jī)質(zhì)對兩種典型雄性激素光解的影響[D];大連理工大學(xué);2013年
，本文編號(hào)：2202977
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