本文選題：NaA沸石分子篩膜 + 介孔NaA沸石晶體��； 參考：《浙江大學(xué)》2015年碩士論文

【摘要】：NaA沸石分子篩膜具有很強(qiáng)的親水性,在有機(jī)物脫水領(lǐng)域有著廣泛的應(yīng)用前景。雖然目前國(guó)內(nèi)外已經(jīng)有NaA沸石分子篩膜滲透汽化的工業(yè)化裝置,但是降低NaA沸石分子篩膜的成本仍然是重要的研究方向。采用中空纖維和大孔氧化鋁管作載體有望降低NaA沸石分子篩膜的成本。采用中空纖維作載體時(shí)可以獲得高通量的沸石分子篩膜,但是常用的納米晶種的制備過(guò)程復(fù)雜；而采用廉價(jià)的大孔氧化鋁管作載體時(shí)沸石分子篩膜的通量較低。針對(duì)這兩個(gè)問(wèn)題,本論文進(jìn)行了以下兩個(gè)方面的研究：(1)提出采用介孔沸石晶體制備納米晶種,使用浸涂-滾擦法涂晶,利用二次生長(zhǎng)法在中空纖維表面制備沸石分子篩膜；(2)為了充分利用介孔沸石的低擴(kuò)散阻力,在大孔氧化鋁管表面構(gòu)建介孔沸石組成的分子篩膜。主要的研究?jī)?nèi)容和結(jié)果如下：(1)由介孔NaA沸石剝離的納米晶體作晶種制備N(xiāo)aA沸石分子篩膜合成了帶有介孔的NaA沸石分子篩晶體,簡(jiǎn)稱(chēng)介孔NaA沸石。通過(guò)簡(jiǎn)單的刮擦和研磨證明了介孔NaA晶體的機(jī)械強(qiáng)度低于普通NaA晶體。研磨10 min可以由微米級(jí)的介孔NaA晶體得到約10%的納米晶體,而從普通NaA沸石晶體得到的碎塊非常少。因此,采用研磨的介孔NaA晶體晶種液在氧化鋁中空纖維載體表面由浸涂法涂晶后,100℃合成僅2h可以誘導(dǎo)生成致密的NaA沸石分子篩膜。將此晶種液離心除去微米級(jí)顆粒后,在中空纖維表面浸涂-滾擦涂晶,100℃合成3 h得到的膜層致密均一,對(duì)90 wt%的乙醇/水溶液在75℃下的分離因子大于10,000,通量達(dá)到8.38kgm-2h-1。而由普通NaA晶體采用相同方法制得的膜層由于缺少足夠的晶種而存在明顯的孔洞和缺陷�？偠灾�,納米NaA晶體容易通過(guò)研磨微米級(jí)的介孔NaA晶體和低速離心分離(或較長(zhǎng)時(shí)間沉降)而獲得,避免了傳統(tǒng)方法合成納米沸石晶體所需的復(fù)雜分離步驟,且收率高。由此獲得的納米沸石晶體不僅能用于沸石分子篩膜的制備,還有望用于催化等其他領(lǐng)域。(2)介孔沸石晶體直接作晶種制備N(xiāo)aA沸石分子篩膜將介孔沸石晶體直接作為晶種采用浸涂-滾擦的涂晶方式,在氧化鋁中空纖維載體表面成功制備了NaA沸石分子篩膜�？疾炝艘院胁煌榭左w積的NaA-1、NaA-3和NaA-5為晶種合成的膜層分離性能,結(jié)果表明沸石晶體含有的介孔體積越高,越容易誘導(dǎo)合成出致密的沸石分子篩膜。當(dāng)使用NaA-5介孔晶體為晶種時(shí),水熱合成1h即可以得到分離因子大于10,000的約600 nm厚的超薄膜,通量高達(dá)9.32kgm-2h-1。通過(guò)與傳統(tǒng)方法合成的180 nm納米晶體誘導(dǎo)的膜層進(jìn)行對(duì)比,證明了介孔NaA-5晶體刮擦涂晶后在載體表面覆蓋了一層大小約為120nm的晶體的晶種層,而且小晶體對(duì)于中空纖維載體上成膜具有更好的促進(jìn)作用。(3)介孔NaA沸石分子篩膜的制備研究嘗試了在大孔氧化鋁管上構(gòu)建介孔NaA沸石分子篩膜,考察了合成方式、晶種類(lèi)型、涂晶方式、合成液堿度和致介孔劑TPHAC(二甲基十六烷基[3-(三甲氧基硅基)丙基]氯化銨)含量以及硅源類(lèi)型對(duì)于介孔NaA沸石分子篩膜形貌和分離性能的影響,然后通過(guò)焙燒去除致介孔劑,最后對(duì)焙燒后的膜層進(jìn)行修復(fù)。研究結(jié)果表明,轉(zhuǎn)動(dòng)合成的方式能夠保證致介孔劑TPHAC在合成液中均勻分散,而且普通NaA沸石晶體比介孔沸石晶體作為晶種更容易誘導(dǎo)致密膜層。與此同時(shí),較低的晶化速率以及適中的TPHAC含量有利于形成致密的介孔NaA沸石分子篩膜,例如以九水硅酸鈉為硅源時(shí),采用2.5 Na2O:SiO2:0.67 A12O3:200 H2O: 0.03 TPHAC的配方；或者以晶化速度較慢的硅酸鈉為硅源,采用2.2 Na2O:2 SiO2: A12O3:150 H2O:0.03 TPHAC的配方。在除去致介孔劑的方式上,通過(guò)350℃焙燒理論上可以除去TPHAC,但是膜層結(jié)構(gòu)發(fā)生了坍塌、變形和開(kāi)裂。采用再次合成的方式可以對(duì)焙燒后的NaA沸石分子篩膜進(jìn)行一定的修復(fù),提高膜層的分離因子。
[Abstract]:NaA zeolite membrane has a very strong hydrophilic property and has a wide application prospect in the field of organic dehydration. Although there have been an industrial device for Pervaporation of zeolite membrane of NaA zeolite at home and abroad, it is still an important research direction to reduce the cost of molecular sieve membrane of NaA zeolite. It is expected to reduce the cost of NaA zeolite membrane. The high throughput zeolite membrane can be obtained when hollow fiber is used as carrier, but the preparation process of the commonly used nanocrystalline species is complex, while the flux of zeolite membrane is low when the cheap macroporous alumina tube is used as the carrier. The following two problems are discussed in this paper. The two aspects: (1) the preparation of nanocrystalline crystals by mesoporous zeolite crystals, the use of dip coating and scrubbing, and the preparation of zeolite membranes on the surface of hollow fibers by the two growth method; (2) in order to make full use of the low diffusion resistance of mesoporous zeolite, the mesoporous zeolite membrane is constructed on the surface of the mesoporous alumina tube. The contents and results are as follows: (1) the mesoporous NaA zeolite membrane was prepared from the mesoporous NaA zeolite to prepare the mesoporous zeolite molecular sieve crystal, which was referred to as mesoporous NaA zeolite. Through simple scraping and grinding, the mechanical strength of the mesoporous NaA crystal was lower than that of the ordinary NaA crystal. The mesoporous NaA crystals of the rice grade obtained about 10% of the nanocrystalline crystals, and the fragments obtained from the ordinary NaA zeolite crystals were very small. Therefore, the grained mesoporous NaA crystal seed liquid was coated on the surface of the alumina hollow fiber carrier by dip coating, and the synthesis of only 2H could induce the formation of dense NaA zeolite membrane. After removing the micron grade particles, dipping on the surface of the hollow fiber and rolling the coated crystal, the film is compact and homogeneous at 100 C for 3 h. The separation factor of the 90 wt% ethanol / water solution at 75 C is greater than 10000, the flux is up to 8.38kgm-2h-1. and the membrane made by the same method by the common NaA crystal is obvious because of the lack of enough crystal. In conclusion, nano NaA crystals are easily obtained by grinding micron mesoporous NaA crystals and low velocity centrifugation (or long time settlement), avoiding the complex separation steps required by traditional methods for the synthesis of nanoscale crystals, and high yield. It is also expected to be used in catalysis and other fields. (2) the mesoporous zeolite crystal is directly prepared for the preparation of NaA zeolite membrane, and the mesoporous zeolite crystal is directly used as the seed of the crystal. The NaA zeolite membrane has been successfully prepared on the surface of the alumina hollow fiber carrier. The NaA-1 with different mesoporous volume is investigated. NaA-3 and NaA-5 are the membrane separation properties synthesized by the crystal. The results show that the higher the mesoporous volume of the zeolite crystal is, the more easy to induce the synthesis of dense zeolite membrane. When NaA-5 mesoporous crystal is used as the crystal, the hydrothermal synthesis of 1H can get a super thin film with a separation factor of about 600 nm thicker than 10000, and the flux is as high as 9.32kgm-2h-1. By comparing the 180 nm nanocrystalline films prepared with the traditional method, it is proved that the mesoporous NaA-5 crystal is covered with a layer of 120nm crystals on the surface of the carrier, and the small crystal has a better promoting effect on the film formation on the hollow fiber carrier. (3) the preparation of mesoporous NaA zeolite membrane The preparation of mesoporous NaA zeolite membrane on the macroporous alumina tube was studied. The synthesis method, crystal type, coating mode, synthetic liquid base degree and mesoporous TPHAC (two methyl sixteen alkyl [3- propyl propyl) ammonium chloride) content and silicon source type on the morphology and separation properties of mesoporous NaA zeolite molecular sieve membrane were investigated. The results show that the method of rotation synthesis can ensure that the mesoporous TPHAC is uniformly dispersed in the synthetic liquid, and that the ordinary NaA zeolite crystal is more likely to induce the compact membrane than the mesoporous zeolite crystal as the crystal. Meanwhile, the lower crystal is lower. The rate and the moderate TPHAC content are beneficial to the formation of dense mesoporous NaA zeolite membrane, for example, using nine sodium silicate as the silicon source, using 2.5 Na2O:SiO2:0.67 A12O3:200 H2O: 0.03 TPHAC, or the silicon source with slower crystallization rate of sodium silicate, using the formula of 2.2 Na2O:2 SiO2: A12O3:150 H2O:0.03 TPHAC. In the way of making mesoporous agent, TPHAC can be removed theoretically by calcination at 350 degrees C, but the structure of the membrane is collapsed, deformed and cracked. The re synthesis method can be used to repair the NaA zeolite membrane after roasting and improve the separation factor of the film.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ051.893

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 徐曉春,楊維慎,劉杰,林勵(lì)吾;微波場(chǎng)中NaA型分子篩膜的快速合成[J];科學(xué)通報(bào);2000年08期

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本文編號(hào)：1923477