本文關(guān)鍵詞：納米氧化鐵的優(yōu)化制備及其可見(jiàn)光芬頓降解水中的雙酚S　出處：《哈爾濱工業(yè)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 雙酚S 氧化鐵 非均相芬頓 中空球 高能晶面

【摘要】：雙酚S因其優(yōu)良的物化穩(wěn)定性,被視為雙酚A的理想替代物,廣泛應(yīng)用于聚碳酸酯、環(huán)氧樹(shù)脂、聚酯樹(shù)脂、聚砜、聚醚砜等高分子材料的合成。同時(shí),作為雙酚A的代替品,它也被大量應(yīng)用于熱敏打印紙、食品包裝等日常品的生產(chǎn)。然而,隨著研究深入發(fā)現(xiàn),雙酚S也具有與雙酚A類似的生理毒性。更令人堪憂的是,雙酚S已在地表水體中被頻頻檢出,這對(duì)人類健康構(gòu)成了潛在的威脅。因此,實(shí)現(xiàn)水中雙酚S的高效去除,對(duì)改善水生環(huán)境具有重要的現(xiàn)實(shí)意義。與傳統(tǒng)芬頓技術(shù)相比,均相光芬頓技術(shù)在一定程度能彌補(bǔ)傳統(tǒng)芬頓技術(shù)的不足,然而它依然存在反應(yīng)條件苛刻(p H≤3)、污泥產(chǎn)量多等問(wèn)題。針對(duì)這些問(wèn)題,本研究通過(guò)設(shè)計(jì)、制備經(jīng)濟(jì)環(huán)保的納米氧化鐵固相催化劑,進(jìn)而構(gòu)建綠色、穩(wěn)定的異相光芬頓體系,最終實(shí)現(xiàn)水中雙酚S的高效去除。首先,針對(duì)氧化鐵實(shí)心顆粒所存在的比表面積小、活性點(diǎn)位暴露少等問(wèn)題,本研究提出了“二氧化硅軟模板”合成策略,實(shí)現(xiàn)了氧化鐵中空球的溫和、可控制備。在此基礎(chǔ)上,闡明了氧化鐵中空球微觀結(jié)構(gòu)-物化特性-光芬頓活性三者間的內(nèi)在關(guān)系。三次循環(huán)降解實(shí)驗(yàn)表明,優(yōu)選出氧化鐵異質(zhì)中空球的耐用性和持久性較好。經(jīng)典的捕獲劑實(shí)驗(yàn)結(jié)果表明在該光芬頓體系中起主要氧化作用的活性氧物種分別為超氧自由基和羥基自由基。在可見(jiàn)光照射下,優(yōu)選出的氧化鐵異質(zhì)中空球?qū)﹄p酚S的降解率為30%,高于實(shí)心氧化鐵納米顆粒(商業(yè)品)的3%。分析原因是異質(zhì)氧化鐵中空球具有較大的比表面積、發(fā)達(dá)的孔隙結(jié)構(gòu),因此有利于催化劑活性點(diǎn)位的充分暴露,進(jìn)而產(chǎn)生活性物質(zhì),以實(shí)現(xiàn)雙酚S的有效降解。雖然通過(guò)中空化處理(即微觀結(jié)構(gòu)的物理優(yōu)化)可提高氧化鐵的比表面積和材料表面的活性點(diǎn)位的數(shù)量,但仍不足以克服氧化鐵作為光催化劑所固有的本征缺陷,如光生電子-空穴易復(fù)合等問(wèn)題。針對(duì)這個(gè)問(wèn)題,本研究在合成制備氧化鐵時(shí)原位引入具有超高遷移率的石墨烯,進(jìn)而獲得了不同形貌氧化鐵/石墨烯復(fù)合催化劑。氧化降解實(shí)驗(yàn)表明氧化鐵量子點(diǎn)/石墨烯復(fù)合催化劑的光芬頓活性最高。自由基捕獲實(shí)驗(yàn)和熒光光譜數(shù)據(jù)表明該體系里起主要降解作用的活性物質(zhì)為羥基自由基。在可見(jiàn)光照射下,優(yōu)選出的氧化鐵量子點(diǎn)/石墨烯復(fù)合催化劑對(duì)雙酚S的去除率可達(dá)83%,高于氧化鐵異質(zhì)中空球的30%。分析原因是石墨烯的引入一方面可有效阻礙光生電子空穴的復(fù)合,另一方面二維石墨烯納米片會(huì)對(duì)雙酚S產(chǎn)生較為強(qiáng)烈的吸附作用(40%)。為獲得催化活性更高的氧化鐵納米材料,進(jìn)一步提出了“二氧化硅水凝膠協(xié)助溶解重結(jié)晶”的合成策略,成功制備了(110)高能晶面暴露的氧化鐵超薄納米片。在可見(jiàn)光照射下,以氧化鐵納米片所構(gòu)建的光芬頓體系對(duì)雙酚S的去除率高達(dá)91%(注:吸附僅占3%),高于商業(yè)P25二氧化鈦的56%,且遠(yuǎn)高于氧化鐵納米顆粒(合成品)的16.6%。分析原因是:1)由于光生電子在(110)晶面的遷移率非常高,導(dǎo)致光生載流子的分離效果好,使得參與后續(xù)反應(yīng)的光生電子數(shù)量增多;2)氧化鐵納米片的厚度僅為3.2 nm,能有效克服光生空穴擴(kuò)散路程短的缺陷(2 4 nm),使得參與后續(xù)反應(yīng)的光生空穴數(shù)量增多;3)由于催化劑具有超薄二維片層結(jié)構(gòu),使得其比表面積較大,活性點(diǎn)位的暴露較為充分。最后,采用UPLC/MS對(duì)雙酚S的降解產(chǎn)物進(jìn)行了鑒定。結(jié)果表明雙酚S的降解產(chǎn)物主要有二羥基苯磺酸、羥基苯磺酸、3-烯丙氧基-1-丙磺酸和苯酚鈉。據(jù)此,可推斷羥基化是驅(qū)動(dòng)雙酚S分解的主要機(jī)制。
[Abstract]:Bisphenol S is regarded as an ideal substitute for bisphenol A because of its excellent physical and chemical stability. It is widely used in the synthesis of polycarbonate, epoxy resin, polyester resin, polysulfone, polyethersulfone and other polymer materials. At the same time, as a substitute for bisphenol A, it has also been widely used in thermal printing paper, food packaging and other daily goods production. However, with the further study, bisphenol S also has a physiological toxicity similar to that of bisphenol A. What is more worrying is that bisphenol S has been detected frequently in the surface water, which poses a potential threat to human health. Therefore, the efficient removal of bisphenol S in water is of great practical significance for the improvement of aquatic environment. Compared with the conventional Fenton technique, homogeneous light Fenton technology in a certain extent can make up the insufficiency of traditional Fenton technology, but it still exists in harsh reaction conditions (P, H = 3), sludge production and other issues. In order to solve these problems, we design and prepare an economical and environmental protection nano iron oxide solid phase catalyst, and then construct a green and stable heterogeneous optical Fenton system. Finally, we can achieve efficient removal of bisphenol S in water. First of all, aiming at the problems of small specific surface area and little exposure of active sites for iron oxide solid particles, a silica soft template synthesis strategy is proposed to achieve the mild and controllable preparation of iron oxide hollow spheres. On this basis, the intrinsic relationship between the microstructure and physicochemical properties of the iron oxide hollow sphere, the three of the light Fenton activity, is clarified. The three cyclic degradation experiments showed that the optimization of the durability and durability of the iron oxide heterogeneous hollow sphere was better. The experimental results of the classic capture agent show that the active oxygen species, which have the main oxidation in the light Fenton system, are superoxide radicals and hydroxyl radicals, respectively. Under the light of visible light, the degradation rate of bisphenol S is 30%, which is higher than that of solid iron oxide nanoparticles (commercial products), which is higher than 3% of the solid iron oxide nanoparticles. The reason for the analysis is that the heterogeneous iron oxide hollow spheres have large specific surface area and well-developed pore structure. Therefore, it is beneficial to fully expose the active sites of catalysts and produce active substances, so as to achieve the effective degradation of bisphenol S. Though the medium cavitation treatment (i.e. physical optimization of microstructure) can improve the specific surface area of iron oxide and the number of active sites on the material surface, it is still not enough to overcome inherent defects of iron oxide as photocatalyst, such as photoelectron hole recombination. To solve this problem, we synthesized in situ the graphene with ultra-high mobility in the preparation of ferric oxide, and obtained different morphologies of iron oxide / graphene composite catalyst. The oxidation degradation test showed that the light Fenton activity of the iron oxide quantum dot / graphene composite catalyst was the highest. The free radical capture experiment and fluorescence spectrum data show that the main bioactive substance in the system is hydroxyl radical. Under the light of visible light, the optimal removal rate of the ferric oxide quantum dot / graphene composite catalyst for bisphenol S is up to 83%, which is higher than that of 30% of the iron oxide hollow sphere. The reason for the analysis is that the introduction of graphene can effectively obstruct the recombination of photoelectron holes. On the other hand, two-dimensional graphene nanosheets will strongly adsorb bisphenol S (40%). In order to obtain iron oxide nanomaterials with higher catalytic activity, we further put forward the synthetic strategy of "silica gel assisted dissolution and recrystallization", and successfully prepared (110) iron oxide ultra-thin nanosheets exposed to high energy crystal surface. Under visible light irradiation, the removal rate of bisphenol S by Fe Fenton nanosheets was as high as 91% (3%). The removal rate of bisphenol P25 was 56% higher than that of commercial TiO2, which was much higher than that of iron oxide nanoparticles (16.6%). The reasons are: 1) because of the photogenerated electrons in the crystal face (110) the migration rate is very high, resulting in separation of photogenerated carriers, which participate in the subsequent reaction of photogenerated electron number; 2) iron oxide nano film thickness is 3.2 nm, can effectively overcome the photohole diffusion in the short distance the defect (24 nm), which involved in the subsequent reaction of the photogenerated hole number; 3) because the catalyst has thin two-dimensional layer structure, the larger specific surface area, active sites exposed to more fully. Finally, UPLC/MS was used to identify the degradation products of bisphenol S. The results show that the degradation products of bisphenol S mainly include two hydroxy benzenes sulfonic acid, hydroxybenzenes sulfonic acid, 3- allyl -1- propane sulfonic acid and sodium phenol. Therefore, it is inferred that hydroxylation is the main mechanism to drive the decomposition of bisphenol S.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：X703

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本文編號(hào)：1344114