本文選題：NaA沸石膜 + 滲透蒸發(fā)　； 參考：《大連理工大學(xué)》2015年碩士論文

【摘要】：針對NaA沸石膜應(yīng)用滲透蒸發(fā)技術(shù)進行有機物脫水中的沸石膜水熱穩(wěn)定性問題,使用大孔β-Al2O3為載體,采用凝膠合成液體系與澄清合成液體系成功制備NaA沸石膜,比較二者在不同醇類脫水中的水熱穩(wěn)定性,初步探討了影響水熱穩(wěn)定性的因素。(1)在不添加模板劑的情況下,采用水熱合成法,考察了不同硅源(硅溶膠,Na2SiO3·9H2O, TEOS)對NaA分子篩的結(jié)晶度、形貌、粒徑的影響。采用硅溶膠作為硅源成功合成了立方晶體狀的亞微米級NaA分子篩。以硅溶膠為硅源,探討了陳化時間、晶化時間、無機鹽對分子篩產(chǎn)物的作用。優(yōu)化后的合成條件為：30℃陳化15h,90℃晶化16h。無機鹽同樣對NaA分子篩有影響。添加NaCl顯著提高了產(chǎn)物的結(jié)晶度,NaCl濃度越高,結(jié)晶度越高；添加Na2SO4則出現(xiàn)了其他晶體,說明在Na2SO4作用下,產(chǎn)物趨向于生成更穩(wěn)定的晶體,影響產(chǎn)品純度。添加0.05 Na2SO4,產(chǎn)物中出現(xiàn)了NaX；添加0.1 Na2SO4產(chǎn)物中出現(xiàn)了方鈉石。(2)在固定硅鋁比的情況下,按照摩爾比Al2O3:2SiO2:XNa2O:YH2O,研究了膜合成因素凝膠合成液堿度,水量,晶化時間對膜性能的影響規(guī)律。優(yōu)化確定最佳合成液摩爾組成Al2O3:2SiO2:2.2Na2O:240H2O,晶化時間為4-4.5h。用掃描電鏡表征膜的形貌和厚度。SEM顯示形成厚度為5-7μm連續(xù)致密的膜層。利用乙醇含量為90wt.%的乙醇水原料液在348K進行滲透蒸發(fā)實驗來考察其分離性能。PV測試實驗結(jié)果顯示滲透側(cè)水含量為99.8583wt.%,其分離因數(shù)α≥6,000以上,通量F可達1.970kg/(m2·h)。(3)按照組成摩爾比Al2O3:5SiO2:50Na2O:1000H2O配置澄清合成液,在25℃陳化6h,80℃動態(tài)晶化5h,在管式α-Al2O3載體表面成功制得NaA沸石膜(膜X),其厚度為4-5μm。將其與凝膠合成液制得的膜(膜N)進行水熱穩(wěn)定性的對比,膜N與膜X進行連續(xù)性的PV實驗,做通量F與滲透側(cè)水含量的時間依存性曲線。實驗結(jié)果表明：(a)膜N在不同醇水分離體系、不同溫度、不同水量的原料液中,均具有優(yōu)異的水熱穩(wěn)定性,經(jīng)過長時間的PV實驗,仍保持較高的分離效果,但通量出現(xiàn)了明顯的下降；(b)膜X在經(jīng)過連續(xù)性的PV測試后,完全喪失分離效果,即a=1,同時通量出現(xiàn)了大幅升高。且水量越高、溫度越高,失去分離效果的時間越短。膜X在低水含量的條件下相對穩(wěn)定； (c)膜X在PV后的SEM中可見裂痕及針孔狀缺陷,表明在載體管與膜的熱膨脹系數(shù)不匹配,晶間相在高水含量下不穩(wěn)定。膜N的SEM圖中未見針孔及裂痕。PV測試后,膜N與膜X的結(jié)晶度少量提高,并出現(xiàn)了新的特征峰,推測可能為SOD。
[Abstract]:The hydrothermal stability of zeolite membrane in the dehydration of organic matter by pervaporation was applied to the NaA zeolite membrane. Using the macroporous beta -Al2O3 as the carrier, the NaA zeolite membrane was successfully prepared by using the gel synthesis liquid system and the synthetic liquid system. The hydrothermal stability of the two groups in different alcohols dehydration was compared, and the water thermal stability was preliminarily discussed. (1) the influence of different silicon sources (silica sol, Na2SiO3. 9H2O, TEOS) on the crystallinity, morphology and particle size of NaA molecular sieves was investigated by hydrothermal synthesis without the addition of template agent. The cubic crystalline submicron NaA molecular sieve was successfully synthesized by silica sol as a silicon source. The silica sol was used as the silicon source to explore Chen Huashi. The optimum synthesis conditions are: aging 15h at 30 C and crystallization of 16h. inorganic salts at 90 degrees C also have an effect on NaA molecular sieves. Adding NaCl significantly improves the crystallinity of the products, the higher the NaCl concentration, the higher the crystallinity, and the addition of Na2SO4 to other crystals, indicating that the production of Na2SO4 is produced under the action of Na2SO4. The product tends to produce a more stable crystal and affects the purity of the product. Adding 0.05 Na2SO4, NaX appears in the product, and the addition of 0.1 Na2SO4 products in the product. (2) under the condition of the ratio of fixed silicon to aluminum, the film synthesis factors are studied in accordance with the molar ratio Al2O3:2SiO2:XNa2O:YH2O. The optimum composition of the synthetic liquid was determined by Al2O3:2SiO2:2.2Na2O:240H2O. The crystallization time was 4-4.5h.. The morphology and thickness of the membrane were characterized by scanning electron microscope (SEM) and the thickness of.SEM was shown to form a continuous and dense film with a thickness of 5-7 mu m. The separation performance.PV was investigated by the pervaporation experiment of ethanol water raw material with ethanol content as 90wt.% in 348K. The test results show that the water content of the osmotic side is 99.8583wt.%, the separation factor is more than 6000 and the flux F can reach 1.970kg/ (m2. H). (3) the clarified synthetic liquid is arranged in accordance with the molar ratio Al2O3:5SiO2:50Na2O:1000H2O, and the 5h is crystallized dynamically at 25, 80, and 6h, and the NaA zeolite membrane (X) is successfully prepared on the surface of the tubular alpha -Al2O3 carrier. The thickness of the membrane is of the thickness. The thermal stability of the membrane (membrane N) produced by the gel synthesis solution is compared with 4-5 m.. The membrane N and the membrane X are continuous PV experiments, and the time dependence of the flux F and the osmotic water content is made. The experimental results show that (a) the membrane N has excellent water and heat stability in different alcohol water separation systems, different temperature and different water content. Qualitatively, after a long time PV experiment, the high separation effect remained high, but the flux decreased obviously; (b) after the continuous PV test, the membrane X completely lost the separation effect, that is, a=1, and the flux increased greatly. And the higher the water, the higher the temperature, the shorter the time of the separation effect. The condition of the membrane X in the low water content It is relatively stable; (c) the crack and needle hole like defects of the membrane X in the SEM after PV show that the thermal expansion coefficient of the carrier tube and the membrane is not matched, the intercrystalline phase is unstable under the high water content. The crystallinity of the membrane N and the membrane X is slightly higher after the SEM diagram of the membrane N is not tested, and a new characteristic peak is presented, presumably for SOD..
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ051.893

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