Preparation and characterization of polysulfone mixed matrix membrane incorporated with palladium nanoparticles in the inversed microemulsion for hydrogen separation

Polysulfone (PSf) membrane shows acceptable gas separation performance, but its application is limited by the “trade-off” between selectivity and permeability. In this study, PSf mixed matrix membranes (MMMs) incorporated with palladium (Pd) nanoparticles in the inversed microemulsion were proposed for hydrogen (H₂) separation. Pd nanoparticles can be kinetically stabilized and dispersed using electrostatic and/or steric forces of a stabilizer which is typically introduced during the formation of Pd nanoparticles in the inversed microemulsion. Pd nanoparticles were synthesized by loading (PdCl₂) into the polymeric matrix, polyethylene glycol (PEG) which acts as reducing agent and stabilizer. The dry–wet phase inversion method was applied for the preparation of asymmetric PSf MMMs. The effects of Pd (0–4 wt%) on the membrane characteristics and separation performance were studied. Experimental findings verified that the MMMs are able to achieved a high H₂/N₂ selectivity of 21.69 and a satisfactory H₂ permeance of 46.24 GPU due to the changes in membrane structure from fully developed finger-like structure to closed cell structure besides the growth of dense layer. However, the selectivity of H₂/CO₂ decreased due to the addition of PEG.     

GO-TSC/聚酰亚胺混合基质膜的制备及气体分离性能研究

使用氨基硫脲（TSC）对氧化石墨烯（GO）进行改性,制备GO-TSC层状复合材料。随后,将该复合材料加入到Matrimid^®5218（PI）基质中,制备用于二氧化碳分离的混合基质膜（MMMs）。通过TGA、SEM及气体分离性能测试考察了GO-TSC对膜热稳定性、结构和气体分离性能等的影响。SEM结果显示GO-TSC可均匀分散在聚合物基质上并与基质紧密结合;TGA结果显示混合基质膜在250 ℃以上仍保持稳定。与纯PI膜相比,MMMs显著增强了二氧化碳的渗透性。GO-TSC中所含的氨基与二氧化碳具有良好的亲和力,增加的碱性位点可以有效地转运二氧化碳。GO-TSC的层状结构增加了气体的传输路径,不利于大动态直径气体（甲烷、氮气）的通过,从而提高了分离性能。GO-TSC负载量为0.75%（质量分数）时混合基质膜的分离性能最佳。相比较纯PI膜,混合基质膜的二氧化碳渗透系数和二氧化碳/甲烷、二氧化碳/氮气分离系数分别提高了42.16%、95.79%和83.72%。     

Fabrication of Pebax/SAPO mixed matrix membranes for CO2/N2 separation

Mixed matrix membranes (MMMs) were prepared by solvent evaporation method using Pebax-1074 polymer as matrix and inorganic zeolite SAPO-23 as dopant. The morphology, surface functional groups, microstructure, thermal stability, and separation performance of MMMs were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and gas permeation, respectively. The effects of dopant loading amount, permeation temperature, and permeation pressure on the structure and properties of MMMs were investigated. The results showed that the introduction of SAPO zeolite reduced the crystallinity of the MMMs and improved the CO₂/N₂ selectivity. Under the conditions of 30°C and 0.15 MPa, the MMMs prepared by incorporating with 5% SAPO zeolite in content exhibited the highest CO₂/N₂ selectivity of 72.0 together with the CO₂ permeability of 98.2 Barrer.     

Fabrication of cellulose acetate ultrafiltration membrane with diphenyl ketone via thermally induced phase separation

With diphenyl ketone as diluent, cellulose acetate (CA) ultrafiltration (UF) membrane with a bicontinuous structure was prepared via thermally induced phase separation (TIPS) method. The liquid–liquid phase separation region of CA/diphenyl ketone system was measured and the maximum corresponding polymer concentration was approximately 53 wt %. The effects of polymer concentration, coarsening time and coarsening temperature on the morphologies, and mechanical properties of CA membranes were investigated systematically. As the polymer concentration increased from 15 to 30 wt %, the bicontinuous structure could be obtained and the tensile strength of CA membranes increased from 3.92 to 30.17 MPa. With the increase of coarsening time, the thickness of dense skin layer and the asymmetry of cross‐section reduced. However, excess coarsening rendered the membrane morphology evolved from a bicontinuous structure to a cellular structure. When the coarsening time was 5 min, the bicontinuous structure in cross‐section showed good interconnectivity and the dense skin layer exhibited a thin thickness of 2 μm. The fabricated CA hollow fiber UF membrane exhibited a high tensile strength of 31.00 MPa and rejection of 96.10% for dextran 20 kDa. It is indicated that diphenyl ketone is a competitive diluent to prepare CA membranes with excellent performance via TIPS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42669.     

改善无机填料混合基质膜气体分离性能的研究进展

混合基质膜（MMMs）是结合了无机填料和有机基质特点的一类膜材料,因其在气体分离应用上具有良好的渗透通量和分离性能被广泛关注。无机填料诸如二氧化硅纳米颗粒球、沸石分子筛、金属有机框架（MOF）、氧化石墨烯（GO）、碳纳米管（CNT）均被广泛应用于混合基质膜的制备,但是碍于无机填料在有机相中的分散性问题、两相相容性问题和界面缺陷问题,常会导致较差的气体分离性能。针对近年通过对无机填料进行表面官能化修饰、共价交联、多元填充、调控形貌等来改善混合基质膜气体分离性能的研究进行总结和阐述,并对其未来的发展趋势进行了展望。     

Facile preparation of Cu(I) impregnated MIL‐101(Cr) and its use in a mixed matrix membrane for olefin/paraffin separation

Cu(I) impregnated MIL‐100(Cr) [denoted Cu@MIL‐101(Cr)] is fabricated by a facile method and utilized in mixed matrix membranes (MMMs) for propylene/propane separation. Cu(I) is prepared from a CuCl₂ solution via mild reduction process using sodium sulfite as the reducing agent. The filler is incorporated into a polystyrene‐b‐polybutadiene‐b‐polystyrene (SBS) block copolymer matrix to form MMMs. As a result, both the permeability and selectivity of propylene/propane are improved after Cu(I) impregnation. The best performance is obtained for SBS/Cu@MIL‐101(Cr) MMM, and these values represent 17% and 54% improvements compared to those of SBS/MIL‐101(Cr) MMM, respectively. This result is attributed to the π‐complexation of the loaded Cu(I) by propylene gas, indicating that Cu@MIL‐101(Cr) with internal Cu(I) and a high pore volume acted as an effective filler to aid propylene/propane separation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46545.     

界面聚合法制备用于脱氮提纯CH4的N2优先渗透ZIF-90/聚酰胺混合基质膜

作为一种高效的分离方法,膜法分离非常规天然气具有较理想的应用前景。相较CH₄优先渗透膜,N₂优先渗透膜优势在于分离N₂/CH₄混合气后CH₄处于高压侧,利于后续处理。以均苯三甲酰氯为油相单体,间苯二胺为水相单体,采用界面聚合法在聚砜基膜上制备致密超薄聚酰胺分离层,并通过向其中引入孔径可允许N₂分子通过而不允许CH₄分子通过的纳米颗粒ZIF-90,在膜内形成固定的N₂传递通道,成功制备了用于脱氮提纯CH₄的N₂优先渗透混合基质膜。膜渗透选择性能测试结果显示当混合基质膜中纳米颗粒掺杂量为0.30 g·L^-1时,2 bar（1 bar=0.1 MPa）进料压力下,N₂渗透速率达1.16×10^-9 mol·m^-2·s^-1·Pa^-1,N₂/CH₄分离因子达16.6,分离因子比未掺杂ZIF-90的聚酰胺膜提高46.5%,具有一定的处理非常规天然气脱氮提纯甲烷的应用潜力。     

界面聚合法制备用于脱氮提纯CH4的N2优先渗透ZIF-90/聚酰胺混合基质膜

作为一种高效的分离方法,膜法分离非常规天然气具有较理想的应用前景。相较CH₄优先渗透膜,N₂优先渗透膜优势在于分离N₂/CH₄混合气后CH₄处于高压侧,利于后续处理。以均苯三甲酰氯为油相单体,间苯二胺为水相单体,采用界面聚合法在聚砜基膜上制备致密超薄聚酰胺分离层,并通过向其中引入孔径可允许N₂分子通过而不允许CH₄分子通过的纳米颗粒ZIF-90,在膜内形成固定的N₂传递通道,成功制备了用于脱氮提纯CH₄的N₂优先渗透混合基质膜。膜渗透选择性能测试结果显示当混合基质膜中纳米颗粒掺杂量为0.30 g·L^-1时,2 bar（1 bar=0.1 MPa）进料压力下,N₂渗透速率达1.16×10^-9 mol·m^-2·s^-1·Pa^-1,N₂/CH₄分离因子达16.6,分离因子比未掺杂ZIF-90的聚酰胺膜提高46.5%,具有一定的处理非常规天然气脱氮提纯甲烷的应用潜力。     

Synthesis of dual-functionalized mixed matrix membrane with amino-GO-Bent/PVDF for efficient separation of CO2/CH4 and CO2/N2

Mixed matrix membranes (MMMs), which combine the characteristics of inorganic nanofillers and organic matrices, have received wide attention because of their good permeability and selective performance for separating CO₂ from industrial waste gases. In this work, the amino-GO-loaded bentonite (amino GO-Bent) was prepared by loading  NH₂ on the GO surface with a large number of functional sites. Firstly, by introducing  NH₂ on the surface of GO and then interacting with bentonite (Bent) organically modified by silane coupling agents through amide bonding. Mixed matrix membranes (MMMs) with an area of 623.7 cm² and homogeneous texture were prepared using amino-GO-Bent as inorganic filler to improve the membrane selectivity for CO₂/N₂ and CO₂/CH₄ separation. The results show that the introduction of amino GO-Bent in MMMs can greatly improve the CO₂ permeability and obtain high CO₂ permeation performance: 2.67945 × 10⁻⁷ cm³ (STP)·cm/s/cm²/cmHg, and the selectivity of CO₂/N₂ and CO₂/CH₄ can reach 307.28 and 325.97, respectively. The two selective values were 14 and 18 times higher than those of pure PVDF membranes, and the performance of MMMs far exceeded the Robeson upper limit in 2008, respectively.     

Fabrication and characterization of Matrimid/MIL-53 mixed matrix membrane for CO2/CH4 separation

In this study, gas separation properties of Matrimid/MIL-53 mixed matrix membranes with different MOF weight percentages (0–20 wt.%) were investigated. TEM, XRD and DLS analysis were implemented to investigate MIL-53, structure and particles size distribution. SEM, FTIR, DSC and TGA analyses were conducted to characterize the fabricated membranes. The SEM images of these membranes showed good adhesion between polymer and particles, although for 20% MIL-53 loading, particles agglomeration was observed in some areas. Moreover, surface images of the membranes showed adequate dispersion of the particles in the polymer matrix, especially at lower MOF loadings. The permeability of pure CO₂ and CH₄ gases for all membranes were measured and the ideal CO₂/CH₄ selectivity was calculated. CH₄ permeability of membranes increased slightly as the percentage of loading increased. At 20 wt.% MOF loading, void formation led to a significant increase in CH₄ permeability (300% over pure Matrimid). CO₂ permeability showed the same trend; there was a 94% increase in permeability compared to pure Matrimid for 15 wt.% MMMs. CO₂/CH₄ selectivity also increased as MOF loading increased. The highest selectivity was shown for 15 wt.% MOF loading. This membrane had 84% growth in selectivity over pure Matrimid. Although at 20 wt.% MIL-53 loading, membrane separation performance was destroyed.     

Polyurethane-SAPO-34 mixed matrix membrane for CO2/CH4 and CO2/N2 separation

SAPO-34 nanocrystals (inorganic filler) were incorporated in polyurethane membranes and the permeation properties of CO₂, CH_4, and N₂ gases were explored. In this regard, the synthesized PU-SAPO-34 mixed matrix membranes (MMMs) were characterized via SEM, AFM, TGA, XRD and FTIR analyses. Gas permeation properties of PU-SAPO-34 MMMs with SAPO-34 contents of 5 wt%, 10 wt% and 20 wt% were investigated. The permeation results revealed that the presence of 20 wt% SAPO-34 resulted in 4.45%, 18.24% and 40.2% reductions in permeability of CO_2, CH_4, and N₂, respectively, as compared to the permeability of neat polyurethane membrane. Also, the findings showed that at the pressure of 1.2 MPa, the incorporation of 20 wt% SAPO-34 into the polyurethane membranes enhanced the selectivity of CO₂/CH₄ and CO₂/N₂, 14.43 and 37.46%, respectively. In this research, PU containing 20 wt% SAPO-34 showed the best separation performance. For the first time, polynomial regression (PR) as a simple yet accurate tool yielded a mathematical equation for the prediction of permeabilities with high accuracy (R² > 99%).     

聚乙烯胺/Cu3（BTC）2-MMT-NH2混合基质膜的制备及气体传递性能

采用阳离子交换与Cu₃(BTC)₂原位合成相结合制备Cu₃(BTC)₂-MMT,同时,借助3-氨基丙基三乙氧基硅烷(KH550)氨基功能化制备Cu₃(BTC)₂-MMT-NH₂杂化材料。然后,将杂化材料添加到聚乙烯胺(PVAm)基质中作为选择性涂层涂覆到聚砜(PSf)支撑体上,制备了PVAm/Cu₃(BTC)₂-MMT-NH₂混合基质膜。通过XRD和FTIR对杂化材料的晶态结构和化学结构进行了表征,同时采用ATR-FTIR证实了Cu₃(BTC)₂-MMT-NH₂杂化材料与PVAm基质之间存在氢键相互作用。系统性研究了PVAm/Cu₃(BTC)₂-MMT-NH₂混合基质膜中MMT阳离子交换量、Cu₃(BTC)₂-MMT与KH550的质量比、Cu₃(BTC)₂-MMT-NH₂的负载量、操作压力、湿膜厚度、操作温度以及混合气作为原料气对膜CO₂渗透性、CO₂/N₂选择性的影响。结果表明：在纯气气氛,操作温度为25℃、操作压力为1 bar(1 bar=0.1 MPa)的条件下,当Cu₃(BTC)₂-MMT-NH₂负载量为3%(质量)时,膜的气体分离性能最优,CO₂渗透率为203 GPU(1GPU=10^-6 cm³·cm^-2·s^-1·cmHg^-1,1 cmHg=1333.22 Pa),CO₂/N₂选择性为100.7,远高于添加MMT、Cu₃(BTC)₂和MMT/Cu₃(BTC)₂混合物的混合基质膜。这是由于Cu₃(BTC)₂-MMT-NH₂具有层间快速传递通道且与聚合物基质有良好的相容性。此外,混合气测试条件下,混合基质膜运行360 h,仍能保持优异的CO₂分离性能稳定性。     

聚乙烯胺/Cu3（BTC）2-MMT-NH2混合基质膜的制备及气体传递性能

采用阳离子交换与Cu₃(BTC)₂原位合成相结合制备Cu₃(BTC)₂-MMT,同时,借助3-氨基丙基三乙氧基硅烷(KH550)氨基功能化制备Cu₃(BTC)₂-MMT-NH₂杂化材料。然后,将杂化材料添加到聚乙烯胺(PVAm)基质中作为选择性涂层涂覆到聚砜(PSf)支撑体上,制备了PVAm/Cu₃(BTC)₂-MMT-NH₂混合基质膜。通过XRD和FTIR对杂化材料的晶态结构和化学结构进行了表征,同时采用ATR-FTIR证实了Cu₃(BTC)₂-MMT-NH₂杂化材料与PVAm基质之间存在氢键相互作用。系统性研究了PVAm/Cu₃(BTC)₂-MMT-NH₂混合基质膜中MMT阳离子交换量、Cu₃(BTC)₂-MMT与KH550的质量比、Cu₃(BTC)₂-MMT-NH₂的负载量、操作压力、湿膜厚度、操作温度以及混合气作为原料气对膜CO₂渗透性、CO₂/N₂选择性的影响。结果表明：在纯气气氛,操作温度为25℃、操作压力为1 bar(1 bar=0.1 MPa)的条件下,当Cu₃(BTC)₂-MMT-NH₂负载量为3%(质量)时,膜的气体分离性能最优,CO₂渗透率为203 GPU(1GPU=10^-6 cm³·cm^-2·s^-1·cmHg^-1,1 cmHg=1333.22 Pa),CO₂/N₂选择性为100.7,远高于添加MMT、Cu₃(BTC)₂和MMT/Cu₃(BTC)₂混合物的混合基质膜。这是由于Cu₃(BTC)₂-MMT-NH₂具有层间快速传递通道且与聚合物基质有良好的相容性。此外,混合气测试条件下,混合基质膜运行360 h,仍能保持优异的CO₂分离性能稳定性。     

Enhanced compatibility and selectivity in mixed matrix membranes for propylene/propane separation

Mixed matrix membranes (MMMs) based on metal–organic framework (MOF) have great promising application in separation of gas mixtures. However, achieving a good interfacial compatibility between polymer and MOF is not straightforward. In this work, focusing on one of the most challenging olefin/paraffin separations: propylene/propane (C₃H₆/C₃H₈), we demonstrate that modification of the MOF filler via dopamine polymerization using a double solvent approach strongly improves interfacial compatibility. The resulting membranes show an outstanding separation performance and long-term stability with propylene permeability nearly 90 Barrer and propylene/propane selectivity close to 75. We anticipate that similar MOF modification strategies may help solve the problem of interface defects in the manufacture of MMMs and be extended to other porous fillers.     

Size effects of graphene oxide on mixed matrix membranes for CO2 separation

Graphene oxide (GO)‐polyether block amide (PEBA) mixed matrix membranes were fabricated and the effects of GO lateral size on membranes morphologies, microstructures, physicochemical properties, and gas separation performances were systematically investigated. By varying the GO lateral sizes (100–200 nm, 1–2 μm, and 5–10 μm), the polymer chains mobility, as well as the length of the gas channels could be effectively manipulated. Among the as‐prepared membranes, a GO‐PEBA mixed matrix membrane (GO‐M‐PEBA) containing 0.1 wt % medium‐lateral sized (1–2 μm) GO sheets showed the highest CO₂ permeation performance (CO₂ permeability of 110 Barrer and CO₂/N₂ mixed gas selectivity of 80), which transcends the Robeson upper bound. Also, this GO‐PEBA mixed matrix membrane exhibited high stability during long‐term operation testing. Optimized by GO lateral size, the developed GO‐PEBA mixed matrix membrane shows promising potential for industrial implementation of efficient CO₂ capture. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2843–2852, 2016     

ZIF-L/PDMS混合基质膜蒸气渗透耦合发酵强化乙醇生产效率的研究

蒸气渗透（VP）膜分离不存在膜污染风险,在生物乙醇生产中具有广阔的应用前景。将聚二甲基硅氧烷（PDMS）膜和以二维沸石咪唑骨架（ZIF-L）为填充基质制备的PDMS（ZIF-L/PDMS）混合基质膜,分别用于VP膜分离与菊粉水解液发酵制乙醇过程的耦合,分析了二者在耦合过程中的分离性能和发酵性能。探究了不同膜分离方式、不同类型膜及操作条件对膜分离性能的影响。实验结果表明,当料液浓度为5%（质量）、蒸气循环流量为1.5 L·min^-1时,ZIF-L/PDMS混合基质膜的VP性能高于渗透汽化（PV）,归一化总通量达到1148.78 g·m^-2·h^-1,分离因子高达19.14,显著提升了乙醇分离性能。ZIF-L/PDMS混合基质膜用于VP耦合发酵,实现了耦合过程的高渗透性和乙醇选择性,与文献报道相比,乙醇移除效果最优,乙醇产率和时空产率分别达到0.421 g·g^-1、3.07 g·L^-1·h^-1,两个指标明显高于单独发酵,极大地提高了乙醇生产效率。因此,ZIF-L/PDMS混合基质膜在原位分离发酵乙醇方面具有很大的应用潜力。     

混合基质膜在碳捕集领域的研究进展

膜分离技术因其低成本、低能耗及高效率的优势被认为是最具有前景的碳捕集技术之一。混合基质膜结合了有机材料与无机材料两方面的优势,是同时提升渗透性和选择性的有效手段。本文从气体在混合基质膜中的传递机制出发,以常见的无孔型与多孔型无机填料为基础,总结了近年来混合基质膜在二氧化碳捕集领域的研究进展,介绍了不同类型的填料在高分子基质中所起到的微结构调节作用,并着重阐述了在混合基质膜制备过程中无机填料与高分子基质之间所存在的相容性问题及其解决方法。最后,提出混合基质膜应在继续致力于填料结构设计、填料分散、构效关系等方面的同时,加强二维填料、微囊填料和促进传递机制等方面的研究。     

脂肪酶改性醋酸纤维的性能研究

采用脂肪酶Lipex 100L对醋酸纤维进行脱乙酰化处理,改善纤维的吸湿、染色等性能;通过脂肪酶处理残液的紫外光谱分析、反应液pH值变化以及染料对纤维的吸附量、回潮率、取代度测试等方法,分析酶处理后反应液中水解产物的产生和纤维表面官能团的变化.结果表明:脂肪酶处理醋酸纤维后,反应液中有水解产物乙酸存在,醋酸纤维的回潮率...