Advanced Membranes最新文献

Developing energy-saving membrane and technology is important for the separation of hydrocarbon isomers to replace the energy-intensive distillation. Silicalite-1 membrane is a promising membrane material but difficult to be scaled up. In this work, separation performance of industrial-scale monolithic silicalite-1 membranes in term of actual butane mixtures has been reported for the first time. Each 61-channel monolithic membrane has effective area and surface-to-volume ratio of 0.2 ​m² and 400 ​m²/m³, which are about 20 and 5.6 times higher than that of the common tubular one with the same length, respectively. Average n-butane/i-butane separation factor (34) of the industrial-scale membranes was even higher than or comparable to that of the reported small-area zeolite membranes. The influences of test parameters on permeances and separation factors of the membranes and the long-term stability were examined. Reynold numbers was used to correlate the concentration polarization (CP) with the reduction of separation performance. A solution was proposed to reduce the effect of CP. It suggests that the industrial-scale and high-performance monolithic silicalite-1 membranes are suitable for actual applications of butane separation.

Membrane technology holds immense potential across multiple industries, offering sustainable solutions for challenging separations by reducing energy demand and transitioning from thermal to electrical energy. The inherent diversity of membrane technology results in various transport scenarios and phenomena, rendering robust process evaluation and optimization challenging. Addressing this problem, we formulate the cascading selectivity principle (CSP), a universal concept applicable across all membrane separation types, including gas, liquid, and particle filtration. Introducing a distinction between primary and secondary permselectivity, the CSP provides a theoretical basis for novel efficiency indices. We also present the first highly versatile selectivity merit descriptors for true membrane cross-comparison. We demonstrate the advantages of the novel descriptors through a series of real-life nanofiltration, ion separation, gas separation, membrane reactor, and ultrafiltration examples. Facilitated by an online calculator tool, this work offers a standardized framework for academic and industrial professionals to implement pioneering membrane separation systems efficiently across the multiple disciplines of membrane technology.

Metal-organic framework (MOF)-based mixed matrix membranes (MMMs) have attracted significant attentions for their distinguished characteristics in pervaporation such as enhanced selectivity, increased permeability and improved mechanical strength through the synergistic integration of polymeric matrices and inorganic fillers. Although many publications have emerged in recent years focusing on MOF-based MMMs, this review specifically emphasizes the improvement of MOF-based pervaporation membranes through the design of dimension of fillers and microstructure. The challenges encountered in MOF-based MMMs for pervaporation and the essential requirements for practical separation applications are addressed. A brief summary of strategies is provided for designing MOF-based MMMs with desired microstructure, macrostructure and multicomponent characteristics by using MOFs as fillers. The latest progresses in novel MOF-based MMMs with specific compositions, controllable pore structure and improved compatibility for recovery of organics are also displayed. The broad application prospects of MOF-based MMMs in pervaporation are introduced, including recovery of ethyl alcohol, butanol and other organics. Moreover, the challenges faced in the practical application of MOF-based MMMs for recovery of organics are presented and the promising future directions are outlined.

Hemodialysis acts as an artificial kidney that selectively removes specific toxins, bio-compounds, or fluid from the main blood stream in a patient with kidney failure. The current process uses ultrafiltration-based membrane technology, where a semi-permeable material selectively extracts chemicals, such as uremic retention products, or remove excess water from blood by retaining certain compounds based on their size. As sugars, fats, proteins, biomolecules, cells, and platelets move into and across the tubular membrane in the hemodialysis process, the surface of the membrane begins to foul, which leads to major operational challenges that include sharp pressure drops with increasing operation times. The design of membranes with enhanced biocompatibility and anti-fouling properties is one avenue to increase the lifespan of the membrane used while facilitating the device operation and limiting the stress and discomfort of patients. This review presents interfacial interactions between blood components and membrane materials used in hemodialysis. The discussion analyzes the impacts of the hemodialyzer module design, membrane material morphology and surface chemistry on the long-term operation and performance of the hemodialyzers. Avenues for the development of next-generation-membrane-materials as well as new strategies to enhance the selective removal of toxic compounds from blood are also discussed.

Spray coating has been exploited to fabricate and tailor the morphologies of various components in thin film composite membranes separately. For the first time, here we exploit this technology to construct and assemble both the selective layer and porous support of a thin-film composite membrane in a single process. In our approach, spray-assisted non-solvent induced phase inversion and interfacial polymerization reduced the time required to fabricate thin-film composite membranes from 3 – 4 days to 1 day and 40 ​min. Our approach did not sacrifice membrane separation performances during desalination of a mixture comprising 2000 ​ppm of NaCl in water at 4 ​bar and room temperature. At these conditions, compared to traditional thin film composite membranes, the water permeance of our spray coated membranes was higher by 35.7 %, reaching 2.32 ​L ​m⁻² ​h⁻¹ bar⁻¹, while achieving a NaCl rejection rate of 94.7 %. This demonstrated the feasibility of fabricating thin film composites via spray coating in a single process, potentially reducing fabrication time during scale-up production.

Polymers of intrinsic microporosity (PIMs) stand out as promising membrane materials with exceptional separation performance. In this study, we crafted a highly efficient gas separation membrane using an emerging material, called cyclohexyl-fused spirobiindane-based PIM (CCS-PIM). The CCS-PIM features a robust and rigid microporous structure with a high specific surface area (S_BET ​= ​704.6 ​m²/g), exhibiting excellent CO₂-selective adsorption capacity. The CO₂ adsorption uptake is 0.78 ​mmol/g at 273 ​K and 0.15 ​bar, leading to IAST selectivity of 25.2 for CO₂/N₂ (15/85 v/v) and 16.7 for CO₂/CH₄ (50/50 v/v) at 298 ​K. The precisely tuned pore size of the CCS-PIM membrane leads to an enhanced molecular sieving effect, showcasing superior selectivity across various gas pair separations. It demonstrates an O₂/N₂ selectivity of 6.03 and a CO₂/CH₄ selectivity of 26.1, surpassing the 2008 Robeson upper bounds. This study suggests a strategic method to improve gas separation efficiency by customizing a locked PIM structure with precise molecular sieving through the insertion of variously sized rings.