本文關(guān)鍵詞：阿特拉津及其光解產(chǎn)物三聚氰酸的電子束輻照降解研究　出處：《上海大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 阿特拉津 三聚氰酸 電子束降解 產(chǎn)物機(jī)理分析

【摘要】：阿特拉津作為被廣泛使用的除草劑,在地表和地下水中無(wú)處不在,屬于一種環(huán)境內(nèi)分泌干擾物,對(duì)生態(tài)環(huán)境和人類(lèi)具有毒性和毒害作用,同時(shí),前人研究發(fā)現(xiàn),在光降解阿特拉津過(guò)程中,降解反應(yīng)進(jìn)行到三聚氰酸就無(wú)法被降解了。并且在水體環(huán)境中,當(dāng)三聚氰酸和三聚氰胺共存時(shí),對(duì)生態(tài)環(huán)境的毒性會(huì)顯著增強(qiáng)。因此,采取有效的降解礦化阿特拉津及其光解產(chǎn)物三聚氰酸手段成為緊迫而關(guān)鍵的任務(wù)。本實(shí)驗(yàn)研究表明,通過(guò)電子束輻照能夠?qū)崿F(xiàn)對(duì)阿特拉津的徹底的降解礦化而沒(méi)有任何三聚氰酸的殘留。在純水中阿特拉津的電子束輻照降解遵循一級(jí)降解動(dòng)力學(xué)。在純水中,濃度為6mg/L的阿特拉津能夠在較低輻照劑量(0.5k Gy)時(shí),其降解率就達(dá)到90%以上,并且同時(shí)伴隨氯離子的有效釋放。上述劑量下,氯離子的轉(zhuǎn)化率達(dá)到85%。通過(guò)光解與電子束降解三聚氰酸的對(duì)比實(shí)驗(yàn)發(fā)現(xiàn):在紫外光解阿特拉津的過(guò)程中,濃度為6mg/L的阿特拉津生成的三聚氰酸的量,濃度一直升高到0.8mg/L之后保持不變,且紫外輻照100h之后,三聚氰酸沒(méi)有任何被降解的跡象;而在電子束輻照降解阿特拉津的過(guò)程中,輻照劑量低于20k Gy時(shí),濃度為6mg/L的阿特拉津生成三聚氰酸的濃度一直升高,濃度最大值可到3.14mg/L。在輻照劑量為60k Gy時(shí),濃度為6mg/L的阿特拉津生成的三聚氰酸逐漸被降解到0.37mg/L。三聚氰酸在不同氧化和還原條件的降解效果比較結(jié)果如下:通入氮?dú)夂褪宥〈夹纬傻倪�原條件下降解最好,其次是通入空氣形成的氧化還原條件,最差是通入氧氣形成的氧化條件。此研究表明,不同自由基對(duì)阿特拉津和三聚氰酸作用有所差別,其中水合電子對(duì)阿特拉津和三聚氰酸的降解礦化起著重要的作用。在電子束輻照降解阿特拉津過(guò)程中,依據(jù)離子產(chǎn)物分析推測(cè)阿特拉津的降解路徑和機(jī)理可能為:水合電子將阿特拉津的側(cè)鏈氯還原為氯離子,側(cè)鏈的烷基被羥基自由基氧化為甲酸,之后聚合形成草酸,并且氨基側(cè)鏈既可以被羥基自由基氧化為硝酸根,又可以被水合電子還原形成銨根離子,隨著輻照劑量的升高,阿特拉津的缺電子苯氮環(huán)逐漸被水合電子攻擊開(kāi)環(huán),使得苯氮環(huán)中的氮元素大量地被水合電子轉(zhuǎn)化形成銨根離子,同時(shí),苯氮環(huán)中的碳元素被轉(zhuǎn)化為甲酸,之后聚合為草酸。在電子束輻照降解三聚氰酸的過(guò)程中,也依據(jù)離子產(chǎn)物分析推測(cè)三聚氰酸的降解路徑和機(jī)理可能為:水合電子直接攻擊缺電子苯氮環(huán)致使其開(kāi)環(huán),將苯氮環(huán)中的氮還原為銨根離子,苯氮環(huán)中的碳降解為甲酸,之后兩個(gè)甲酸聚合成草酸。綜上所述,電子束輻照能夠降解礦化阿特拉津,形成無(wú)機(jī)離子和有機(jī)小分子,同時(shí)也能降解礦化阿特拉津光降解產(chǎn)物三聚氰酸。相比于一般高級(jí)氧化技術(shù),尤其是光降解,電子束輻照是一種降解阿特拉津及其光降解產(chǎn)物三聚氰酸的有效且安全的手段。
[Abstract]:As a widely used herbicide atrazine, ubiquitous in groundwater and surface water, is a kind of environmental endocrine disruptors, on the ecological environment and human toxicity and toxic effects, at the same time, previous studies found that, in the light of atrazine degradation process, the degradation reaction of cyanuric acid cannot be degraded and in water environment. And when cyanuric acid and melamine coexist, the ecological environment will significantly enhance the toxicity. Therefore, effective degradation of atrazine and its degradation products of cyanuric acid means become urgent and crucial task. The experimental results show that the electron beam irradiation can be achieved on the atrazine completely without any degradation of residues of cyanuric acid degradation of atrazine in water. The electron beam irradiation followed the first-order degradation kinetics. In pure water, the concentration of 6mg/L at Lazin can at low dose irradiation (0.5K Gy), the degradation rate is above 90%, and at the same time with the effective release of chloride ions. The chloride ion dose, conversion rate reached 85%. by contrast experiment and electron beam photolysis degradation of cyanuric acid found in the process of UV solution of atrazine in concentration for atrazine 6mg/L generation of cyanuric acid amount, concentration has been increased to remain unchanged after 0.8mg/L, and 100h after UV irradiation, cyanuric acid without any signs of degradation; and in the process of electron beam irradiation degradation of atrazine, irradiation dose is lower than 20K Gy when the concentration of 6mg/L of atrazine generated cyanuric acid has been increased, the maximum concentration to 3.14mg/L. at dose of 60K Gy, the concentration of atrazine 6mg/L generated cyanuric acid was degraded gradually to three 0.37mg/L. in different polycyanate The degradation effect of oxidation and reduction conditions, the results are as follows: under the condition of the best degradation reduction by adding nitrogen and tert butyl alcohol formation, followed by oxidation with air formed by reducing conditions, the worst is to pass into the oxidation conditions. This study shows that the formation of oxygen free radical, different different of atrazine and cyanuric acid. Among them, degradation of the hydrated electron of atrazine and cyanuric acid. It plays an important role in the electron beam irradiation of atrazine degradation process, based on degradation pathways and mechanism of atrazine ion product analysis may be: hydrated electron will restore the side chain of chlorine atrazine was chlorine ion, the alkyl side chain oxidation by hydroxyl radicals for after the polymerization to form formic acid, oxalic acid, and amino side chain hydroxyl radical can be oxidized to nitrate, but also by the hydrated electron reduction to form ammonium ions, with radiation The exposure dose increased, electron deficient benzene ring nitrogen atrazine was gradually hydrated electron attack ring opening, the nitrogen benzene nitrogen ring is heavily hydrated electron formation of ammonium ions, at the same time, the carbon nitrogen in benzene ring was transformed into formic acid, oxalic acid in the process of polymerization after electron beam irradiation. The degradation of cyanuric acid, also based on the analysis of product ion degradation pathways and mechanism of cyanuric acid may be: hydrated electrons directly attack the electron deficient benzene nitrogen ring resulting in the open loop, the reduction of nitrogen in the nitrogen cycle for ammonium ion, carbon nitrogen degradation of benzene ring in formic acid, after two formic acid polymerization into oxalic acid. In summary, electron beam irradiation can degrade atrazine mineralization, the formation of inorganic ions and small organic molecules, but also degradation of the photodegradation of atrazine to cyanuric acid. Compared to the general product of advanced oxidation technology, especially optical degradation, Electron beam irradiation is an effective and safe method for the degradation of atrazine and Its Photodegradation product of cyanuric acid.

【學(xué)位授予單位】：上海大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：X592

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;Radiolytic decomposition of 4-bromodiphenyl ether[J];Nuclear Science and Techniques;2010年02期

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本文編號(hào)：1373453