混合基质膜

Abstract(#br)In this contribution, zeolitic imidazolate framework (ZIF-8)/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared for hydrocarbon recovery using propane/nitrogen mixture as a model feed gas pair. All MMMs obtained a homogeneous particle dispersion and intimate interface interaction, which were confirmed by high resolution scanning electric microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) mapping.

Abstract(#br)Separation of ethanol/water mixtures through classical separation methods, like distillation, are very energy consuming. Pervaporation is an alternative membrane separation process with much lower energy demand, but still lacking high performance membranes with sufficient flux-selectivity properties. In this study, polydimethylsiloxane (PDMS) based mixed matrix membranes (MMMs) were developed and their pervaporation performance investigated. The fillers consist of hollow spheres (HS) covered with a shell of silicalite-1 crystals.

Abstract(#br)Free-standing zeolitic imidazolate framework-71 (ZIF-71)/polydimethylsiloxane (PDMS) nanocomposite membranes with 0, 5, 25 and 40\u003cce:hsp sp=\"0.25\"/\u003ewt% ZIF-71 loadings were prepared and the pervaporation separation performance for ethanol and 1-butanol from water was measured. ZIF-71 was stable in water for seven days (both at room temperature and 60\u003cce:hsp sp=\"0.25\"/\u003e°C); the crystal structure and morphology remained the same. ZIF-71/PDMS composite membranes were formed through addition cure and condensation cure methods.

Abstract(#br)A highly-efficient zeolitic imidazolate framework-8 (ZIF-8) embedded polydimethylsiloxane (PDMS) mixed matrix membrane (MMM) supported by a polyvinylidene fluoride (PVDF) nanofibrous substrate was developed for phenol removal in an aqueous-aqueous membrane extractive process.

Abstract(#br)High separation performance and superior mechanical properties of the membranes are both of critical importance for membrane modules to achieve high efficiency and long-term stability. Herein, a series of mixed matrix membranes (MMMs) with brick-and-mortar architecture are prepared by incorporating two-dimensional zeolitic imidazolate framework-L (ZIF-L) nanosheets into polydimethylsiloxane (PDMS) matrix for separating alcohols (ethanol, n -propanol or n -butanol) from aqueous solution.

摘要\n本研究借助密度泛函理论计算，基于溶液扩散机制，初步构思了一种独特的MOF封端纳米管结构。然后，制备了新型ZIF-8封端埃洛石纳米管( ZHNTs )，并将其嵌入到聚二甲基硅氧烷( PDMS )本体中，实现了正丁醇渗透汽化的混合基质膜( MMMs )。该膜的显著特点是ZHNTs中的HNT管腔( φ25 nm )为首次通过封盖ZIF-8层筛选的渗透剂提供了精致的扩散通道。同时，ZIF-8层在ZHNTs外表面的紧密连接为分子渗透创造了相对连续的途径。正如预期的那样，ZHNTs的嵌入显著提高了膜的分离性能。令人印象深刻的是，在1 wt %正丁醇水溶液的分离中，40℃时，所得膜的分离因子高达61.3 (比PDMS对照膜高58.7 % )，通量可比683 g m-2 h-1 (是PDMS对照膜的2.43倍)。此外，ZHNTs的存在赋予膜良好的界面相容性、力学性能和长期稳定性。本研究可能对合理设计用于发酵液生物燃料回收的高性能MMMs有所启示。

摘要\n本研究通过在氧化石墨烯( GO )纳米片表面原位生长沸石咪唑酸骨架8 ( ZIF-8 )纳米粒子，制备了具有连续内通道的ZIF-8 @ GO乙醇分子复合材料，并填充到聚二甲基硅氧烷( PDMS )基体中，制备了PDMS / ZIF-8 @ GO混合基质膜( MMMs )，用于渗透蒸发回收乙醇。采用多种技术对所制备的ZIF-8 @ GO复合材料和PDMS / ZIF-8 @ GO MMMs进行了表征。结果表明，ZIF-8纳米粒子均匀分散在GO纳米片表面，ZIF-8 @ GO复合材料的疏水性比GO强，这是由于ZIF-8疏水性对GO进行表面修饰。而且，ZIF-8 @ GO复合材料作为填料不仅与PDMS表现出优异的相容性，而且与ZIF-8纳米粒子相比，在PDMS基体中表现出良好的分散性。因此，ZIF-8 @ GO基MMMs比ZIF-8基MMMs表现出更好的分离性能。通过调节填料种类、颗粒负荷、膜厚和进料温度，研究了PDMS / ZIF-8 @ GO MMMs的渗透蒸发性能。优化后的PDMS / ZIF-8 @ GO MMMs与5 wt %乙醇水溶液在40℃下，总通量为443.8 g / m2 h，分离因子为22.2，与大多数PDMS基MMMs相比，渗透汽化性能更优。优异的渗透汽化结果归因于GO纳米片作为强阻隔剂与具有连续内通道的疏水ZIF-8纳米粒子的协同作用。

摘要\n亲水金属有机骨架( MOFs )和疏水聚二甲基硅氧烷( PDMS )之间的界面相容性通过表面活性剂和聚合物包裹等超分子修饰而不被有效调和。下面我们报道一种共价交联策略来加强MOFs ~ PDMS界面。三甲氧基硅烷( TMS )修饰锆MOFs ( UiO-66 - NH2 )，可进一步与硅醇终止的PDMS反应，增强UiO-66 ~ PDMS界面相容性。高含量的UiO-66 - TMS (最高可达50 wt % )负载到PDMS中，保持了较好的成膜能力、机械性能和渗透汽化选择性，但与原UiO-66 - NH2相比，即使在较低的负载量( 10 wt % )下，膜的强度和分离性能都有所下降。在保持选择性的前提下，混合基质膜在乙醇-水混合脱水中的通量得到了很大的提高。在40℃下连续2次渗透蒸发，可从稀进料中高效生产浓乙醇(等效通量为2234 g / m2 h，渗透液中乙醇质量分数为53 wt % )，且具有共价增强界面的膜在连续运行100 h时性能稳定。

摘要\n联苯基共价三嗪骨架( CTF )粒子作为一类新型的有机多孔材料，被掺入聚二甲基硅氧烷( PDMS )中，制备了用于正丁醇( n- BtOH )回收的高性能渗透汽化膜。增加CTF的负载量显著提高了膜的通量和分离因子。这是由于CTF的强疏水性、高孔性和介孔结构为n- BtOH提供了高透水性和择优性的通道，重要的是，与其他报道的含常规微孔粒子的PDMS基混合基质膜相比，CTF / PDMS ( CTF / PDMS )膜具有更高的通量和更好的分离因子。提高进料温度和n- BtOH浓度进一步增强了渗透汽化性能。因此，将含12.5 wt % CTF的CTF / PDMS膜与4 wt %的n- BtOH进料液在60℃下操作时，n- BtOH的回收率最高(总渗透通量2816±118 g m-2 h-1，分离因子62.8±1.5，渗透n- BtOH浓度71.5±2.7 wt % )。

本研究以BTDA- TDI / MDI ( P84 )共聚酰亚胺为空分工艺基础，引入沸石碳复合材料( ZCC )作为聚合物膜上的新型填料。采用聚二甲基硅氧烷( PDMS )涂层复盖表面缺陷，进一步提高了分离性能。在P84共聚酰亚胺基体中加入1 % ZCC，O2渗透率由7.12提高到18.90 Barrer ( 2.65倍)，O2 / N2选择性由4.11提高到4.92 Barrer ( 19.71 % )。该膜上的PDMS涂层进一步提高了O2 / N2的选择性可达60 %。结果表明，在P84共聚酰亚胺膜上引入ZCC和PDMS涂层可以提高整体空分性能。