【摘要】：近年來(lái),隨著工業(yè)廢水及生活污水等的排放,水質(zhì)被大量的污染。美國(guó)國(guó)家環(huán)保局(USEPA)根據(jù)污染物的毒性、生物降解的可能性以及在水體中出現(xiàn)的幾率等因素,規(guī)定需要優(yōu)先控制的129種有毒物質(zhì),其中有機(jī)污染物有114種,這類有機(jī)污染物在水體中殘留時(shí)間長(zhǎng),有蓄積性和劇毒性等,對(duì)人類有致毒、致癌的性能。由于它們?cè)谒h(huán)境中的痕量濃度,因此開(kāi)發(fā)有效的分析技術(shù)以分析超痕量化合物是至關(guān)重要的。而有機(jī)污染物在生產(chǎn)和使用過(guò)程中進(jìn)入環(huán)境水中達(dá)到一定濃度時(shí),對(duì)農(nóng)業(yè)、林業(yè)等會(huì)帶來(lái)不可預(yù)估的破壞,也會(huì)影響人類和動(dòng)植物的正常生活,因此人們不僅需要對(duì)環(huán)境水中的有機(jī)污染物進(jìn)行檢測(cè),而且還需要對(duì)其進(jìn)行吸附和降解處理。為了達(dá)到更好的富集、吸附和降解效果,所用到的材料通常需要比表面積大,易于分散,與目標(biāo)分析物有較好的作用,處理速度快等特點(diǎn)。石墨相氮化碳(g-C_3N_4)對(duì)富集、吸附和降解有機(jī)芳香族化合物顯示出巨大的潛力。g-C_3N_4的電子離域性質(zhì),賦予了它具有多種吸附機(jī)制,主要包括絡(luò)合效應(yīng),氫鍵,氧化還原反應(yīng),π-π共軛效應(yīng),疏水效應(yīng),酸堿反應(yīng)和靜電相互作用等。然而,g-C_3N_4的分離過(guò)程中需要過(guò)濾或離心,這樣的操作繁瑣并且耗時(shí)。Fe_3O_4納米粒子是最廣泛使用的磁性材料之一,一方面它們具有較好的穩(wěn)定性和較大的比表面積;另一方面,它們?nèi)菀缀铣�、聚�?易于固定在吸附劑表面上,并且不會(huì)有效地吸附分析物。因此,可以將Fe304固定在g-C_3N_4的表面上,以克服單獨(dú)使用g-C_3N_4作為吸附劑時(shí)的不足。此外,g-C_3N_4還具有無(wú)毒和可見(jiàn)光響應(yīng)(半導(dǎo)體帶隙2.7eV),它的這種獨(dú)特的結(jié)構(gòu)決定了其在光催化領(lǐng)域的廣泛應(yīng)用。但是,普通g-C_3N_4的催化活性較小,可以通過(guò)增大其比表面積,這樣有利于目標(biāo)物與g-C_3N_4有更多的接觸,從而提高g-C_3N_4的催化活性。因此本實(shí)驗(yàn)利用合成的新型大比表面積的天鵝絨狀高分散性的V-g-C_3N_4/Fe304納米復(fù)合材料對(duì)多氯聯(lián)苯(PCBs)進(jìn)行富集檢測(cè),對(duì)氯酚(CPs)進(jìn)行吸附處理,最后合成不同比表面積的g-C_3N_4對(duì)氯酚進(jìn)行光催化降解,以選出最佳光催化降解氯酚的材料。具體內(nèi)容和結(jié)果如下:(1) V-g-C_3N_4/Fe_3O_4納米復(fù)合材料的合成及在檢測(cè)環(huán)境水中的多氯聯(lián)苯的應(yīng)用通過(guò)尿素的水輔助一步熱縮合法制備天鵝絨狀的石墨相氮化碳(V-g-C_3N_4),該合成方法簡(jiǎn)單、易于操作。將制備好的V-g-C_3N_4和Fe_3O_4通過(guò)化學(xué)共沉淀法制備V-g-C_3N_4/Fe_3O_4納米復(fù)合材料。然后對(duì)材料進(jìn)行熱分析、元素分析、FT-IR、XRD、BET和TEM表征,結(jié)果表明此納米復(fù)合材料成功合成。然后使用此納米復(fù)合材料,對(duì)十種PCBs的混合溶液進(jìn)行磁性固相萃取,在此過(guò)程中,利用響應(yīng)曲面法(RSM)對(duì)影響固相萃取的因素,如溫度、時(shí)間、pH值、鹽度等進(jìn)行優(yōu)化。使用HPLC測(cè)定優(yōu)化吸附條件和優(yōu)化洗脫條件時(shí)的溶液,而使用GC-MS測(cè)定經(jīng)過(guò)MSPE后的洗脫液,檢測(cè)開(kāi)發(fā)方法對(duì)四種實(shí)際水樣中的PCBs富集的線性和檢測(cè)限。實(shí)驗(yàn)結(jié)果表明,在最優(yōu)條件下:本方法對(duì)PCBs具有較好的檢測(cè)限(9.0×10~(-6)-5.8×10-5μg/mL,LOD,S/N=3)、精密度(0.02-3.7%,RSDs,n=3)和回收率(80.1-118.4%)。這項(xiàng)研究表明V-g-C_3N_4/Fe_3O_4可用于水樣品中預(yù)處理和富集PCBs及其他含有碳基環(huán)結(jié)構(gòu)的疏水性污染物。(2)V-g-C_3N_4/Fe_3O_4納米復(fù)合材料作為吸附劑對(duì)水中的氯酚類化合物的吸附應(yīng)用將所制備的V-g-C_3N_4/Fe304納米復(fù)合材料用作吸附劑,對(duì)水中三種氯酚進(jìn)行吸附處理,探究了氯酚初始濃度、吸附時(shí)間、鹽度、溶液溫度、溶液pH因素的影響,并且用響應(yīng)曲面法對(duì)這些影響因素進(jìn)一步優(yōu)化,以選擇出最佳吸附條件。利用HPLC進(jìn)行分析,以評(píng)價(jià)此材料作為吸附劑時(shí)吸附氯酚類化合物的性能。實(shí)驗(yàn)結(jié)果表明,合成的V-g-C_3N_4/Fe_3O_4具有比表面積大,吸附速率快(30s)等優(yōu)點(diǎn),對(duì)氯酚類化合物吸附處理效果好。(3)不同比表面積的石墨相氮化碳納米材料的合成及在可見(jiàn)光下快速光催化降解氯酚的應(yīng)用通過(guò)三聚氰胺和尿素制備出不同比表面積的g-C_3N_4,在合成過(guò)程中,不必使用模板,有毒溶劑和昂貴的化學(xué)藥品,然后對(duì)這些材料進(jìn)行表征。本實(shí)驗(yàn)選擇三種氯酚作為目標(biāo)化合物,利用HPLC進(jìn)行分析,以評(píng)價(jià)這些材料作為光催化劑的性能。還研究了一些影響光催化降解的關(guān)鍵因素,包括溶液的離子強(qiáng)度,pH和溫度等,優(yōu)化出光催化降解目標(biāo)分析物的最佳條件,然后對(duì)材料重復(fù)利用。最后,在最佳條件下光催化降解氯酚,并用實(shí)時(shí)分析質(zhì)譜(DART-MS)驗(yàn)證降解效果。結(jié)果表明,V-g-C_3N_4 (N2,3h)納米材料對(duì)于CPs溶液的光催化降解效果是最好的,是由于此材料的大的比表面積和良好的分散性能導(dǎo)致。因此,該工作提供了一種高催化活性的光催化劑制備的方法,此催化劑在降解水中的氯酚和其他類似的非極性污染物方面具有潛在的應(yīng)用價(jià)值。
[Abstract]:In recent years, with the discharge of industrial wastewater and domestic sewage, the water quality has been polluted by a large number of pollutants. Because of their trace concentrations in the water environment, it is very important to develop effective analytical techniques for the analysis of ultra-trace compounds. Agriculture, forestry and so on will bring unpredictable destruction, will also affect the normal life of human beings, animals and plants, so people not only need to detect organic pollutants in environmental water, but also need to be adsorbed and degraded. Graphite-phase carbon nitride (g-C_3N_4) shows great potential for enrichment, adsorption and degradation of organic aromatic compounds. The electron delocalization of g-C_3N_4 gives it a variety of adsorption mechanisms, including complexation effect, hydrogen bonding, oxidation and so on. However, the separation of g-C_3N_4 requires filtration or centrifugation, which is cumbersome and time-consuming. Fe_3O_4 nanoparticles are one of the most widely used magnetic materials. On the one hand, they have good stability and large specific surface area. Therefore, Fe304 can be fixed on the surface of g-C_3N_4 to overcome the shortcomings of using g-C_3N_4 as an adsorbent alone. In addition, g-C_3N_4 has non-toxic and visible light response (semiconductor band gap 2.7eV), which is unique. The structure of g-C_3N_4 determines its wide application in the field of photocatalysis. However, the catalytic activity of g-C_3N_4 is small, and the specific surface area of g-C_3N_4 can be increased by increasing the specific surface area of g-C_3N_4, which is beneficial for the target to have more contact with g-C_3N_4, thus improving the catalytic activity of g-C_3N_4. Polychlorinated biphenyls (PCBs) were enriched and detected by V-g-C_3N_4/Fe304 nanocomposites. Chlorophenols (CPs) were adsorbed by V-g-C_3N_4 nanocomposites. Finally, different specific surface areas of g-C_3N_4 were synthesized and photocatalytic degradation of chlorophenols was carried out to select the best materials for photocatalytic degradation of chlorophenols. Synthesis of V-g-C_3N_4 and Fe_3O_4 nanocomposites were prepared by water-assisted one-step pyrolysis of urea. The method was simple and easy to operate. The V-g-C_3N_4 and Fe_3O_4 nanocomposites were prepared by chemical co-precipitation method. The results of thermal analysis, elemental analysis, FT-IR, XRD, BET and TEM show that the nanocomposites were successfully synthesized. Then the magnetic solid-phase extraction of ten kinds of PCBs mixed solution was carried out using the nanocomposites. In this process, the response surface methodology (RSM) was used to analyze the factors affecting the solid-phase extraction, such as temperature, time, pH value, salinity and so on. The optimum conditions were determined by HPLC. The eluent after MSPE was determined by GC-MS. The linearity and detection limit of PCBs enrichment in four kinds of actual water samples were determined by GC-MS. The results showed that under the optimum conditions, the detection limit of PCBs was 9.0 (-6) - 5.8. The results show that V-g-C_3N_4/Fe_3O_4 nanocomposites can be used to pretreat and enrich PCBs and other hydrophobic pollutants containing carbon-based rings in water samples. The V-g-C_3N_4/Fe304 nanocomposites were used as adsorbents to adsorb three kinds of chlorophenols in water. The effects of initial concentration, adsorption time, salinity, solution temperature and pH on the adsorption of chlorophenols were investigated. The response surface methodology was used to optimize these factors in order to select the best adsorption conditions. The results showed that the synthesized V-g-C_3N_4/Fe_3O_4 had the advantages of large specific surface area, fast adsorption rate (30s) and good adsorption effect on chlorophenols. (3) Synthesis of graphite carbon nitride nanomaterials with different specific surface areas The application of rapid photocatalytic degradation of chlorophenols in visible light g-C_3N_4 with different specific surface area was prepared by melamine and urea. During the synthesis process, no templates, toxic solvents and expensive chemicals were used, and then these materials were characterized. Some Key Factors Affecting Photocatalytic degradation, such as ionic strength, pH and temperature of the solution, were studied to optimize the optimal conditions for photocatalytic degradation of target analytes, and then reuse the materials. Finally, photocatalytic degradation of chlorophenol was carried out under the optimal conditions and the real-time analysis was performed. The results showed that V-g-C_3N_4 (N2,3h) nano-material had the best photocatalytic degradation effect on CPs solution because of its large specific surface area and good dispersibility. Therefore, this work provided a method for preparing photocatalyst with high catalytic activity, which could degrade water. Chlorophenols and other similar non-polar pollutants have potential applications.
【學(xué)位授予單位】：南京師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X52;O647.33

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 黃志慧;李育珍;張寧;高利珍;石建惠;;無(wú)機(jī)、有機(jī)及復(fù)合吸附材料處理有機(jī)污染物的研究[J];化學(xué)研究與應(yīng)用;2016年06期

2 張娜;;高效液相色譜-串質(zhì)譜法在保健食品檢測(cè)中的應(yīng)用研究進(jìn)展[J];廣東化工;2016年10期

3 李亞珍;李兆乾;朱華玲;王衛(wèi)平;;磁性石墨烯固相萃取-毛細(xì)管電泳聯(lián)用測(cè)定水樣中三嗪類農(nóng)藥殘留[J];分析化學(xué);2015年12期

4 范艷春;李誠(chéng);;對(duì)地下水中16種特定多環(huán)芳烴的高效液相色譜法檢測(cè)方法的研究[J];華北國(guó)土資源;2015年02期

5 程夢(mèng)婷;劉倩;劉稷燕;江桂斌;;石墨烯在環(huán)境有機(jī)污染物分析中的應(yīng)用進(jìn)展[J];環(huán)境化學(xué);2014年10期

6 王軍;伍水生;趙文波;廉培超;王亞明;;石墨烯基納米材料吸附去除有機(jī)污染物的研究進(jìn)展[J];材料導(dǎo)報(bào);2014年09期

7 郭杰;張朝飛;高庚渠;馬光輝;馬威;;高效液相色譜 串聯(lián)質(zhì)譜聯(lián)用在牛奶抗生素殘留檢測(cè)中的研究進(jìn)展[J];中國(guó)畜牧獸醫(yī);2014年01期

8 高庚申;徐蘭;安裕敏;;紫外—熒光檢測(cè)器高效液相色譜法測(cè)定PM_(2.5)中16種多環(huán)芳烴[J];環(huán)境污染與防治;2013年05期

9 王志;王春;;磁性固相萃取技術(shù)研究的新進(jìn)展[J];色譜;2012年10期

10 鄧敏軍;羅艷;鄧超冰;;固相萃取-氣相色譜-質(zhì)譜法測(cè)定水中的19種多氯聯(lián)苯[J];光譜實(shí)驗(yàn)室;2012年02期

相關(guān)博士學(xué)位論文 前1條

1 侯軍剛;鈦酸鉍材料的制備，，表征及性能研究[D];天津大學(xué);2009年

相關(guān)碩士學(xué)位論文 前4條

1 李功恒;鹽輔助氧化石墨烯分散固相微萃取技術(shù)在環(huán)境有機(jī)污染物分析中的應(yīng)用[D];成都理工大學(xué);2015年

2 周鳳芽;Fe_3O_4/g-C_3N_4復(fù)合材料對(duì)鹵代酚類的磁固相萃取與光催化降解[D];南京師范大學(xué);2015年

3 楊珍;離子液體液相微萃取在土壤中有機(jī)污染物分析中的應(yīng)用[D];西安建筑科技大學(xué);2011年

4 田皓;二氧化鈦光催化劑改性及光催化性能的研究[D];山東師范大學(xué);2010年

本文編號(hào)：2231058