本文選題：EMT沸石　切入點(diǎn)：二次生長(zhǎng)法　出處：《太原理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：NaY沸石膜具有獨(dú)特的三維十二元環(huán)孔道體系，孔徑尺寸為0.74nm，有利于大分子物質(zhì)的分離，骨架中高的鋁含量以及籠穴周圍高度分散的鈉離子，，使其具有較強(qiáng)的親水性和極性，對(duì)親水性和極性強(qiáng)的分子具有較優(yōu)的分離選擇性。碳酸二甲酯（DMC）的合成一般以甲醇（MeOH）為原料，反應(yīng)后常會(huì)存在兩者的共沸物，不易分離；采用酯交換法合成碳酸二苯酯（DPC）過(guò)程中，由于受到熱力學(xué)平衡的限制，反應(yīng)平衡轉(zhuǎn)化率低，同樣存在DMC和MeOH共沸的問(wèn)題，及時(shí)將產(chǎn)物MeOH進(jìn)行有效地分離能夠提高反應(yīng)的轉(zhuǎn)化率。MeOH分子動(dòng)力學(xué)直徑為0.38nm，DMC具有與丙酮和甲基叔丁基醚相似的結(jié)構(gòu)，其動(dòng)力學(xué)直徑與兩者接近（丙酮為0.47nm，甲基叔丁基醚為0.63nm），MeOH分子尺寸小于DMC，且親水性和極性高于DMC。NaY沸石膜作為親水性膜材料能夠優(yōu)先吸附MeOH，對(duì)醇的選擇性較好，同時(shí)NaY沸石膜分離MeOH/DMC的混合物能夠克服有機(jī)膜易溶脹的缺點(diǎn)，穩(wěn)定性好。 本論文考察了合成條件（晶種及晶種層、二次生長(zhǎng)液組成）對(duì)NaY沸石膜微結(jié)構(gòu)的影響，以EMT沸石為晶種，α-A12O3為載體，采用二次生長(zhǎng)法制備了致密且連續(xù)的NaY沸石膜。通過(guò)X-射線衍射（XRD）、掃描電鏡（SEM）、透射電鏡（TEM）等分析測(cè)試手段對(duì)EMT沸石晶種、晶種層及NaY沸石膜進(jìn)行了一系列的表征，并對(duì)沸石膜進(jìn)行了滲透分離性能的檢測(cè)，結(jié)果表明： 1、采用偏鋁酸鈉為鋁源在無(wú)模板劑及低溫條件下合成EMT型沸石，晶粒呈現(xiàn)六方形貌，晶粒大小約為20-30nm左右。以無(wú)水乙醇作為分散介質(zhì)，晶種液濃度為0.1%，晶種擔(dān)載量為1.0mL，晶種能夠完全覆蓋載體，制備均勻完備的晶種層，在此晶種層上，經(jīng)二次生長(zhǎng)可制備連續(xù)致密的NaY沸石膜，膜層厚度約12μm。 2、二次生長(zhǎng)液物質(zhì)的量組成n SiO2: n Al2O3: n Na2O: n H2O=10:1:14:840，在室溫下攪拌陳化24h，于100℃下晶化6h制備的NaY沸石膜交聯(lián)程度較高，沸石膜連續(xù)致密，且沒(méi)有雜晶的出現(xiàn)。 3、NaY沸石膜在50℃條件下滲透分離MeOH/DMC(50wt%)體系，隨滲透時(shí)間的延長(zhǎng)沸石膜保持良好的穩(wěn)定性，總滲透通量為0.110-0.120Kg/(m2·h)，分離因子約為18；隨著原料液中甲醇濃度(20-80wt%)的增大，總滲透通量(0.115-0.137Kg/(m2·h))增加，分離因子(34.2-5)降低；隨著原料液溫度(30-80℃)的升高，總滲透通量(0.09-0.179Kg/(m2·h))增大，分離因子降低(20.9-3)。
[Abstract]:The NaY zeolite membrane has a unique three-dimensional 12 element annular pore system with a pore size of 0.74 nm, which is favorable to the separation of macromolecules. The high aluminum content in the framework and the highly dispersed sodium ions around the cage cavity make the membrane have strong hydrophilicity and polarity. The dimethyl carbonate (DMC) was synthesized with methanol MeOH as raw material. After the reaction, azeotropic compounds were often found, which were not easy to be separated. In the process of synthesis of diphenyl carbonate by transesterification, due to the limitation of thermodynamic equilibrium, the equilibrium conversion of the reaction is low, so there is also the problem of azeotropic reaction of DMC and MeOH. The effective separation of the product MeOH in time can improve the conversion. MeOH molecular dynamics diameter of 0.38 nm DMC has a structure similar to acetone and methyl tert-#china_person0# ether. Its kinetic diameter is close to that of both (acetone is 0.47 nm, methyl tert-#china_person0# is 0.63 nm) and the molecular size of MeOH is smaller than that of DMC, and the hydrophilicity and polarity are higher than that of DMC.NaY zeolite membrane as hydrophilic membrane material, MeOH can be preferentially adsorbed, and the selectivity of alcohol is better. At the same time, NaY zeolite membrane separation of MeOH/DMC mixture can overcome the disadvantages of easy swelling of organic membranes and good stability. In this paper, the effects of synthesis conditions (seed and seed layer, composition of secondary growth liquid) on the microstructure of NaY zeolite membrane were investigated. EMT zeolite was used as seed and 偽 -A12O3 as carrier. Compact and continuous NaY zeolite membranes were prepared by secondary growth method. The seed, seed layer and NaY zeolite membrane of EMT zeolites were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The permeation performance of zeolite membrane was tested. The results showed that: 1. 1. EMT zeolites were synthesized by using sodium metaluminate as aluminum source at low temperature and without template. The grain size is about 20-30nm, and the crystal size is about 20-30nm. Anhydrous ethanol is used as the dispersing medium. The seed liquid concentration is 0.1 and the seed load is 1.0 mL. The seed can cover the carrier completely and prepare a uniform and complete seed layer. On this layer, continuous and compact NaY zeolite membrane can be prepared by secondary growth. The thickness of the film is about 12 渭 m. (2) the composition of n Sio _ 2: n Al _ 2O _ 3: n Na _ 2O: n Na _ 2O: n H _ 2O 10: 10: 1 14: 840, agitated at room temperature for 24 h, and crystallized at 100 鈩

本文編號(hào)：1631264