热浸渍涂晶加旋转晶化制备亲水性ZSM-5沸石膜及其性能表征（英文）

采用热浸渍涂晶加旋转晶化方法在α-Al_2O_3微孔支撑体上合成了ZSM-5沸石膜,并将其应用于异丙醇/水体系渗透汽化脱水。对ZSM-5沸石膜的物相组成和显微结构进行表征,研究了合成时间、晶种浓度、制备方法对ZSM-5沸石膜性能的影响。结果表明:当第一次涂晶浓度为2g/L、二次晶化时间为28h时,制备出的ZSM-5沸石膜交互生长良好,膜层致密。对比3种合成方法(浸渍涂晶加旋转晶化法,热浸渍涂晶加旋转晶化法,热浸渍涂晶加静态晶化法)制备的ZSM-5沸石膜对90%异丙醇渗透汽化脱水性能。结果表明:热浸渍涂晶加旋转晶化法更适合制备亲水性ZSM-5沸石膜,制备出的沸石膜在348K时对90%异丙醇进行渗透汽化脱水,渗透通量可达到1.68 kg/(m~2·h),分离因子为17 991。     

采用复合晶种法在大孔载体上制备高性能ZSM-5沸石膜

采用复合晶种法在α-Al2O3载体上制备ZSM-5沸石膜.首先采用热浸渍-擦涂法在大孔α-Al2O3载体上预涂一层由纳米ZSM-5分子筛团聚而成的大晶种颗粒,对载体表面的大孔进行初步修饰;然后在此基础上利用提拉法涂覆小晶种,从而形成一层薄而连续的晶种层;最后在175℃下利用二次生长法制备ZSM-5沸石膜.采用SEM和XRD等方法,对制备的ZSM-5沸石膜进行表征,并对其进行渗透汽化性能测试.结果表明:制备的ZSM-5膜连续、致密且厚度为8μm;在温度353 K下,分离质量分数为90％的乙酸/水体系,其渗透通量可达0.89 kg/(m2·h),分离系数接近于无穷大.     

PDMS/ZSM-5膜的制备及渗透汽化分离水中乙酸正丁酯和乙酸乙酯

为探究出适合分离水中的乙酸正丁酯和乙酸乙酯的新型渗透汽化膜材料，选用沸石ZSM-5 对聚二甲基硅氧烷(PDMS)材料进行填充改性，以聚偏氟乙烯(PVDF)为支撑层，采用刮涂法制备PDMS/ZSM-5/PVDF复合膜渗透汽化分离水中的乙酸正丁酯和乙酸乙酯。采用SEM、接触角测量仪、FTIR、TGA和XRD等对膜材料物理化学性能进行表征，考察了膜材料的溶胀行为及渗透汽化性能。结果表明，ZSM-5在 PDMS 膜中分散均匀，且没有发生化学作用，并提高了膜材料的疏水性和热稳定性。随着ZSM-5添加量的增加，膜在乙酸正丁酯和乙酸乙酯的溶胀度和待分离组分在膜材料中的扩散速率不断增加。随着进料浓度和温度的增加，渗透通量不断增大，分离因子先增大后减小。随着ZSM-5在PDMS/ZSM-5/PVDF复合膜中含量的增加，总渗透通量增加，而分离因子呈现先增加后减小的趋势。当添加量为10%（质量）时，分离因子达到最大值。对于乙酸正丁酯/水体系，渗透通量和分离因子最大值分别为319 g·m ^-2·h ^-1和131；而对于乙酸乙酯/水体系，渗透通量和分离因子最大值分别为1385 g·m ^-2·h ^-1和121。     

渗透汽化异丙醇脱水ZSM-5沸石膜的制备与表征

采用二次生长法在无有机模板剂条件下水热晶化制备高质量纯相ZSM-5沸石膜。考察了Na2O/SiO_2摩尔比和Na F/SiO_2摩尔比对制备ZSM-5沸石膜及其结构、形貌与渗透汽化异丙醇脱水分离性能的影响。结果表明,在较低Na2O/SiO_2摩尔比或Na F/SiO_2摩尔比下制备的沸石膜膜层结晶度低;而在较高Na2O/SiO_2摩尔比或Na F/SiO_2摩尔比时,易转晶生成mordenite沸石晶体;仅在Na2O/SiO_2摩尔比为0.17、Na F/SiO_2摩尔比为0.9时,制备出高质量纯相ZSM-5沸石膜,其膜层平整、连续、致密且结晶度高,该膜在渗透汽化异丙醇脱水中具有最佳的分离性能,其渗透通量为3.88 kg/(m2·h),水对异丙醇的分离系数达10 000以上。     

以TPABr为模板剂的ZSM-5分子筛膜的合成与表征

以四丙基溴化铵(TPABr)为模板剂,直接在多孔的α-A1_2O_3陶瓷管外表面,经过重复合成制得了渗透通量较大的ZSM-5沸石分子筛膜。以合成ZSM-5沸石的DTA/TGA分析结果为依据,确定了去除ZSM-5沸石膜中模板剂的热处理制度。用X R D和S E M对Z S M-5沸石分子筛膜进行了表征,膜的分离因子用单一的氢气和氮气的渗透通量的比值表示。X RD分析表明陶瓷基质表面的膜层是ZSM-5沸石晶相,S E M结果显示合成的沸石膜层晶体相互交连,形成一种连续的多晶层,厚度约10μm。H_2、N_2对分子筛膜的气体渗透表明,合成的ZSM-5沸石膜的H_2/N_2理想分离因子为2.87。     

亲水型ZSM-5分子筛填充PVA膜及分离乙酸乙酯/水的应用

为了实现低能耗且高效分离乙酸乙酯中的低含量水分，选用亲水型纳米ZSM-5沸石分子筛材料作为改性剂，填充到聚乙烯醇(PVA)聚合物中制备PVA/ZSM-5混合基质膜(MMMs)。采用SEM、FTIR、XRD、TGA和接触角测量仪等对膜材料的形态、物化性质进行表征分析，并考察膜材料在不同溶液中的溶胀行为以及通过单因素实验探究填料含量、进料温度、进料浓度对渗透汽化分离乙酸乙酯和水混合物的性能的影响。结果表明，ZSM-5与PVA结合紧密且分散均匀，除了ZSM-5固有的亲水性外，ZSM-5还与PVA分子之间存在氢键相互作用，但两者之间并没有发生化学作用。随着进料浓度的增加，渗透通量增大，而分离因子呈减小趋势；随着进料温度升高，渗透通量和分离因子均增大；随着ZSM-5填充量的增加，渗透通量和分离因子均先增大后减小。当ZSM-5填充量为6%(质量)时，渗透通量和分离因子达到最大值，分别为1231 g/(m²·h)和6072，相比纯PVA膜分离指数(PSI)提高了2.9倍。新设计的PVA/ZSM-5混合基质膜(MMMs)可在工业水平上用于乙酸乙酯及其他类似化合物的脱水。     

有机硅烷改性ZSM-5/BPPO非对称膜制备及其渗透汽化性能

以硅烷改性ZSM-5分子筛为填充剂,采用沉浸凝胶相转化法制备了ZSM-5/BPPO非对称膜. 结果表明,分子筛在BPPO膜中分散均匀,填充分子筛后膜表面粗糙度增大、疏水性增强. 以低浓度乙醇-水体系为研究对象,考察了分子筛填充量、进料液浓度及进料液温度对ZSM-5/BPPO膜渗透汽化分离性能的影响. 结果表明,随乙醇浓度增大,ZSM-5/BPPO膜的分离因子减小,渗透通量增大;随进料液温度升高,ZSM-5/BPPO膜的分离因子及渗透通量均增大;在60℃、分子筛填充量为0.3%(w)时,ZSM-5/BPPO膜对5%(w)乙醇-水体系的分离因子高达18.49,渗透通量为529.69 g/(m2×h). ZSM-5/BPPO膜对不同醇-水体系的分离结果表明,醇类分子量越大,膜分离性能越好.     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

水热合成高性能丝光沸石膜及其在四氢呋喃脱水中的应用

在不添加模板剂的情况下,通过二次生长合成法在多孔α-Al_2O_3载体外表面制备丝光沸石膜。当结晶温度为160℃,结晶时间为24 h时,丝光沸石膜的渗透通量和分离因子同时达到最大值,分别为0.125 kg/(m~2·h)和840。在水/异丙醇混合物中测试了沸石膜的渗透汽化能力;通过扫描电子显微镜和X射线衍射表征膜的晶体结构和形貌。将得到的丝光沸石膜用于四氢呋喃脱水,通过研究渗透汽化温度和进料浓度对脱水过程的影响,发现丝光沸石膜具有良好的分离性能。     

On a rapid method to characterize intercrystalline defects in zeolite membranes using pervaporation data

This work presents a mass-balance-based model devoted to the characterization of intercrystalline defects active to permeation in film-like zeolite membranes using pervaporation data. Relevant structural information concerning such domains can be obtained from the slope and intercept of the line that describes the increase of the flux pervaporated through a membrane with the absolute pressure in the liquid feed. Capillary forces appear to govern mass transfer within intercrystalline pores. The suitability of the model is assessed by using a collection of zeolite NaA membranes prepared on our premises for the separation of ethanol/water mixtures. The results show that, although a membrane displays high selectivity, a reduced number of defects in the zeolite layers cannot be ruled out. The model offers the advantage of enabling the characterization of large defects in pervaporation membranes at experimental conditions similar to those in which they are likely to be used.     

二次水热合成法制备ZSM-5分子筛膜及其渗透汽化性能

采用二次水热合成法在管状多孔莫来石支撑体上制备高耐酸性ZSM-5分子筛膜,系统地研究分子筛晶种和合成溶胶中H₂O/SiO₂摩尔比率对ZSM-5分子筛膜生长与渗透汽化性能的影响,采用X射线衍射、冷场扫描电子显微镜和电子能谱等表征技术分别对制备的ZSM-5分子筛及其ZSM-5分子筛膜的结构、形貌和Si/Al比进行表征。针对分离75℃、90% HAc/H₂O的水溶液,最优化条件下制备的ZSM-5分子筛膜表现出优良的渗透汽化性能,渗透通量和分离因子分别为0.98kg/(m²·h)和890。此外,本研究所采用制备耐酸性ZSM-5分子筛膜的方法表现出良好的重现性,重复制备的12根ZSM-5分子筛膜在75℃下分离90% HAc/H₂O的水溶液时,平均通量和分离系数分别为（0.85±0.15）kg/(m²·h)和650±290。再者,ZSM-5分子筛膜在45～75℃的温度范围内分离50%～95% HAc/H₂O水溶液时都表现出优良的渗透汽化性能。     

ZSM-5沸石分子筛膜的制备及脱盐性能研究

淡水资源日益短缺,发展膜法海水淡化技术是满足世界淡水供应需求的重要途径,但是寻找合适的膜材料依然是人类面临的挑战。ZSM-5沸石分子筛膜（简称沸石膜）具有规则的孔道结构、合适的孔径尺寸（0.51~0.56 nm）以及可调变的硅铝比,在有机物脱水分离应用中展示了优异的选择性及良好的渗透性和稳定性。基于其孔径尺寸介于水分子和盐离子之间,其在海水淡化脱盐领域也具有应用潜力。在大孔α-Al₂O₃载体上采用二次生长法制备了ZSM-5沸石膜,考察了晶化时间与合成液的硅铝比对ZSM-5沸石膜成膜和渗透蒸发脱盐性能的影响,并采用XRD、SEM、EDS与水接触角表征了合成膜的相结构与结晶度、骨架组成表面特性等膜的结构性质。结果表明：通过二次水热法采用合成液摩尔配比为n（Al₂O₃）∶n（SiO₂）∶n（Na₂O）∶n（NaF）∶n（H₂O）=0.05∶1∶0.21∶1.01∶55的合成液在175℃下晶化48 h为最佳的合成条件,制备了Si/Al比为10、接触角为17.5°的亲水纯相致密ZSM-5沸石膜,并在75℃下对3.5%（质量）的NaCl水溶液进行了渗透蒸发测试,水的通量和盐离子截留率达到8.35 kg·m^-2·h^-1和99.99%,且性能在60 h的时间依存性测试后依然稳定,表现出了很高的海水淡化工业应用潜力。     

ZSM-5填充PDMS复合膜渗透蒸发分离乙醛水溶液(英文)

Hydrophobic ZSM-5 zeolite filled polydimethylsiloxane(PDMS) composite membranes with Nylon micro-filtration membrane as the support layer were prepared to separate acetaldehyde from its aqueous solution.The composite membranes were characterized by Fourier transform infrared spectroscopy and X-ray diffraction.Their structural morphology and thermal stability were also examined.The swelling study showed that the composite membranes presented higher degree of swelling in aqueous solution of acetaldehyde than in pure water at 25 C,suggesting that the membranes have stronger sorption capacity in acetaldehyde solution.The effects of ZSM-5 filling content and acetaldehyde concentration on pervaporation performance of composite membranes were investigated.The permeation experiments at different temperatures showed that both selectivity and permeation flux of composite membranes increased with temperature.With 5%ZSM-5-PDMS/Nylon membrane at acetaldehyde mass concentration of 8% and 25℃,the separation factor of acetaldehyde/water achieved 35 and the permeation flux was 233.3 g·m-2·h-1.     

Modeling investigation of geometric size effect on pervaporation dehydration through scaled-up hollow fiber NaA zeolite membranes

A mass transfer model in consideration of multi-layer resistances through NaA zeolite membrane and lumen pressure drop in the permeate sidewas developed to describe pervaporation dehydration through scaled-up hollowfiber supported NaA zeolitemembrane. Itwas found that the transfer resistance in the lumen of the permeate side is strongly related with geometric size of hollow fiber zeolite membrane,which could not be neglected. The effect of geometric size on pervaporation dehydration could bemore significant under higher vacuumpressure in the permeate side. The transfer resistance in the lumen increaseswith the hollowfiber length but decreaseswith lumen diameter. The geometric structure could be optimized in terms of the ratio of lumen diameter to membrane length. A critical value of dI/L (Rc) to achieve high permeation flux was empirically correlated with extraction pressure in the permeate side. Typically, for a hollow fiber supported NaA zeolite membrane with length of 0.40 m, the lumen diameter should be larger than 2.0 mm under the extraction pressure of 1500 Pa.     

A graphene oxide membrane with self-regulated nanochannels for the exceptionally stable bio-oil dehydration

The transport behaviors and nanochannel structures of a graphene oxide (GO) membrane were studied for pervaporation dehydration of bio-oil with a high acidity and a complex composition. The GO membrane showed an unprecedentedly stable water flux of approximately 0.43 kg m⁻² hr⁻¹, with a water content of 97 wt% in the permeate throughout 70 hr of pervaporation testing at 30°C. Both the calculated activation energy for water permeation and X-ray diffraction characterization results confirmed that the nanochannel structures of the GO membrane were temperature- and liquid media-responsive. The molecular intercalation-induced self-regulation of the size of laminar nanochannels in the GO membrane was suggested to be primarily responsible for the significantly reduced membrane fouling and the exceptionally stable pervaporation performance for the GO membrane. The mechanistic insights into the nanochannel structures and antifouling properties would provide important inspiration for the design of novel highly fouling-resistant membrane materials for practical applications.     

T型分子筛膜的制备及其对含酸乙腈-水的分离性能

石化医药行业会产生大量乙腈废液,通过无机分子筛膜分离技术进行回收可以创造可观的经济价值。然而,乙腈废液水含量较高,并且具有一定的酸性,目前应用比较广泛的NaA型分子筛膜不能在该体系下长期使用。使用自制的平均粒径为600 nm的T型分子筛作为晶种,采用真空涂敷法将晶种负载在α-Al₂O₃载体管表面,在150 ℃下水热晶化16 h制备出T型分子筛膜,并对其做膜性能评价实验。结果表明,自制的T型分子筛膜在进料流量为3.5 L/h、温度为100 ℃条件下对含有1%（质量分数）乙酸和10%水（质量分数）的乙腈混合溶液进行膜分离脱水实验,渗透通量为2.51 kg/（m ²·h）;在120 h长时间运行过程中,分离系数保持在2 250以上,T型分子筛膜性能基本保持不变。