發(fā)布時間：2018-01-01 23:32

  本文關(guān)鍵詞：硝基多環(huán)芳烴在雪中的光解反應(yīng)動力學　出處：《吉林建筑大學》2017年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 硝基多環(huán)芳烴 光解 雪 水

【摘要】：雪是極地地區(qū)和高海拔地區(qū)生態(tài)系統(tǒng)的重要組成部分,降雪過程中,大氣污染物可通過干濕沉降等方式進入雪中,也可以被沉降后的積雪吸附,使得雪成為大氣污染物的重要儲存庫。從20世紀末期開始,研究人員陸續(xù)在極地和高海拔地區(qū)檢測出多種持久性有機污染物(Persistent organic pollutants,POPs)。POPs具有持久性、半揮發(fā)性及高毒性等特性,可長距離的遷移,對人類健康與環(huán)境安全造成持久性危害。據(jù)了解,雪中的POPs可通過揮發(fā)作用進入大氣,也可以通過光化學作用進行轉(zhuǎn)化,且光化學作用可能將POPs轉(zhuǎn)化成持久性更強、毒性更大的產(chǎn)物。硝基多環(huán)芳烴(Nitro polycyclic aromatic hydrocarbons,NPAHs)是一類具有直接致突變和致癌活性的污染物,其致突變性和致癌性遠遠高于其母體多環(huán)芳烴,對環(huán)境及人體健康造成了極大威脅,近年來受到研究人員的廣泛關(guān)注。據(jù)了解,含有四個苯環(huán)的NPAHs的致突變性最高,而含有兩個硝基的NPAHs比單硝基的NPAHs活性要高,汽車尾氣中含量最高的NPAHs是1-硝基芘(1-nitropyrene,1-NP),而1,8-二硝基芘(1,8-dinitropyrene,1,8-DNP)是目前報道過的致突變性最高的化合物。在溫度較低的冰雪環(huán)境中,常規(guī)的化學反應(yīng)較弱,光化學作用是NPAHs在環(huán)境中遷移轉(zhuǎn)化的重要途徑。研究者們對大氣、固體表面和有機溶劑中NPAHs光化學的研究較多,而對水和雪中NPAHs光化學的研究很少。因此,本論文建立了NPAHs的定量分析方法,并通過室內(nèi)模擬實驗,對比研究了紫外光作用下1-NP和1,8-DNP在水和雪中的光轉(zhuǎn)化規(guī)律,建立了1-NP和1,8-dnp在水和雪中的直接光解動力學,并考察了光敏劑(h2o2、no2-、no3-)、bc、fenton、ph值及助溶劑等對npahs光解的影響。得到的結(jié)論如下:一、基于lc-ms/ms的水中痕量npahs的分析方法通過對質(zhì)譜和色譜條件的優(yōu)化,采用帶有大氣壓化學電離源(atmosphericpressurechemicalionization,apci)的高效液相色譜-串聯(lián)質(zhì)譜(lc-ms/ms)測定水中痕量npahs的含量。結(jié)果表明,1-np和1,8-dnp的線性范圍分別為0.72~12μg/l和0.48~48μg/l,相關(guān)系數(shù)r2分別為0.9990和0.9992,回收率分別為97.67%~104.44%和93.33~103.13%,方法檢出限(s/n=3)分別為0.21μg/l和0.15μg/l,定量限(s/n=10)分別為0.72μg/l和0.26μg/l。方法具有不需要前處理、操作簡便、且靈敏度高等優(yōu)點,優(yōu)于其他液相、氣相色譜等檢測方法。二、紫外光作用下npahs在水中的光解(1)紫外光照射下,1-np和1,8-dnp在水中均可發(fā)生光轉(zhuǎn)化反應(yīng),并且符合一級動力學方程。(2)隨npahs初始濃度的增加,其光解速率變慢;(3)在體系中加入光敏劑(h2o2、no2-和no3-)均促進了水中npahs的光解,且光解速率隨光敏劑濃度的增加而變快;(4)fenton對水中npahs光解的影響為先抑制、后促進,且fe2+和h2o2的最佳濃度比為1:3;(5)bc主要通過吸附作用使1,8-dnp從水中去除,光解的貢獻幾乎可以忽略;(6)酸性條件和堿性條件均促進了水中npahs的光轉(zhuǎn)化,且酸性條件下促進效果更好;(7)助溶劑甲醇促進了水中npahs的光解,且甲醇濃度越高,npahs的光解越快。三、紫外光作用下npahs在雪中的光解(1)紫外光照射下,1-np和1,8-dnp在雪中可發(fā)生光轉(zhuǎn)化反應(yīng),并且均符合一級動力學方程。(2)隨1,8-DNP初始濃度的增加,雪中1,8-DNP光解速率變快;(3)低濃度H_2O_2(50μmol/L)對雪中1,8-DNP光解無影響,高濃度H_2O_2(200μmol/L)促進了雪中1-NP的光解;(4)NO_2~-和NO_3~-均促進了雪中NPAHs的光解;(5)Fenton對雪中1-NP和1,8-DNP光解的影響不顯著;(6)BC主要通過吸附作用使1,8-DNP從雪中去除,光解的貢獻幾乎可以忽略;(7)BC與光敏劑(H_2O_2、NO_3~-和NO_2~-)共同作用的情況下均會促進雪中1,8-DNP的光解,其中BC+NO_2~-對雪中1,8-DNP光解的促進更明顯;(8)酸性、堿性條件均促進了雪中1-NP的光解,而酸性條件促進了雪中1,8-DNP的光解,堿性條件抑制了雪中1,8-DNP的光解。
[Abstract]:Snow is an important part of the ecological system of the polar regions and the high altitude, snow process, air pollutants can enter the snow by dry and wet deposition etc., can also be absorbed after the settlement of the snow, the snow has become an important repository of atmospheric pollutants. From the beginning of the end of the twentieth Century, the researchers are in the polar and high altitude areas detection of a variety of persistent organic pollutants (Persistent organic pollutants, POPs.POPs) with persistent, semi volatile and highly toxic properties, can migrate long distances, cause lasting harm to human health and environmental safety. It is understood that the snow POPs can enter the atmosphere through volatilization, can also be carried out by photochemical transformation effect and photochemical effect may be POPs into a more durable, more toxic products. Nitro polycyclic aromatic hydrocarbons (Nitro polycyclic aromatic hydrocarbons, NPAHs) is A class of direct mutagenic and carcinogenic activity of pollutants, the mutagenicity and carcinogenicity of polycyclic aromatic hydrocarbons is much higher than that of its parent, caused a great threat to the environment and human health, have attracted much attention in recent years. It is understood that the mutagenicity of the highest with four benzene rings of NPAHs, which contains two nitro the NPAHs is higher than single nitro NPAHs activity, the content of NPAHs in the automobile exhaust is the highest 1- nitropyrene (1-nitropyrene, 1-NP), and 1,8- two nitropyrene (1,8-dinitropyrene, 1,8-DNP) is caused by mutation of the highest compounds have been reported. In the low temperature environment in the snow, the conventional chemical reaction is weak the photochemical effect, is an important way of migration and transformation of NPAHs in the environment. The researchers studied the solid surface to the atmosphere, and the organic solvent in NPAHs photochemistry, while research on water and snow NPAHs photochemical very little. Therefore, this paper established a method of quantitative analysis of NPAHs, and through the indoor simulation experiment, a comparative study of the effect of UV 1-NP and 1,8-DNP in the water and snow in the light of transformation rules, direct photolysis kinetics of 1-NP and 1,8-dnp in water and snow was established, and the effects of photosensitizer (H2O2, no2-, no3-). BC, Fenton, pH value and effect of CO solvents on the photolysis of NPAHs. The conclusions are as follows: first, the optimization of mass spectrometry and chromatographic conditions through the analysis method of trace NPAHs in water based on lc-ms/ms, with atmospheric pressure chemical ionization source (atmosphericpressurechemicalionization, APCI) by high performance liquid chromatography tandem mass spectrometry (lc-ms/ms) determination of trace NPAHs in water. The results showed that the linear range of 1-NP and 1,8-dnp were 0.72~12 g/l and 0.48~48 g/l, the correlation coefficient R2 were 0.9990 and 0.9992, the recovery rate was 97.67%~104.44% and 93.33~10 3.13%, the limit of detection (s/n=3) were 0.21 g/l and 0.15 g/l, the limit of quantification (s/n=10) were 0.72 g/l and 0.26 g/l. method is not need pretreatment, simple operation, and high sensitivity, better than other liquid chromatography, gas chromatography and other methods. Two, UV photolysis light under the action of NPAHs in water (1) under UV irradiation, 1-NP and 1,8-dnp light conversion reaction in water can be, and in accordance with the first-order kinetic equation. (2) with the increase of initial NPAHs concentration, the photolysis rate slowed down; (3) adding photosensitizer in the system (H2O2, no2- and no3-) were promote the photolysis of NPAHs in water, and the photolysis rate increased with the increase of concentration of the photosensitizer and change rapidly; (4) the effect of Fenton on NPAHs in water photolysis was firstly inhibited, after the promotion, and the optimal concentration of fe2+ and H2O2 is 1:3; (5) BC mainly by adsorption to 1,8-dnp removed from the water, the contribution of photolysis almost can be ignored. 鐣，

本文編號：1366723