Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “membrane separation”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Thin-film composite membrane and processes for the separation of alkenes from a gaseous feed mixture

This invention discloses an improved thin-film composite membrane and processes that use the membrane for the separation of gaseous mixtures that include an alkene. The membrane is particularly useful for separation of alkenes from alkanes or the separation of alkenes from other non-hydrocarbon gases. The membrane has a more mechanically durable and defect-free gas-separation layer that is fabricated from an ionomer solution that is substantially free of dissolved ionic species not associated with the ionomer and the mean helium permeability of the thin-film composite membrane is less than two times greater than the intrinsic helium permeability of the gas-separation layer.

36 MATERIALS SCIENCE↗
NASA NTRS2004

Air Separation Using Hollow Fiber Membranes

The NASA Glenn Research Center in partnership with the Ohio Aerospace Institute provides internship programs for high school and college students in the areas of science, engineering, professional administrative, and other technical areas. During the summer of 2004, I worked with Dr. Clarence T. Chang at NASA Glenn Research Center s combustion branch on air separation using hollow fiber membrane technology. . In light of the accident of Trans World Airline s flight 800, FAA has mandated that a suitable solution be created to prevent the ignition of fuel tanks in aircrafts. In order for any type of fuel to ignite, three important things are needed: fuel vapor, oxygen, and an energy source. Two different ways to make fuel tanks less likely to ignite are reformulating the fuel to obtain a lower vapor pressure for the fuel and or using an On Board Inert Gas Generating System (OBIGGS) to inert the Central Wing Tank. goal is to accomplish the mission, which means that the Air Separation Module (ASM) tends to be bulky and heavy. The primary goal for commercial aviation companies is to transport as much as they can with the least amount of cost and fuel per person, therefore the ASM must be compact and light as possible. The plan is to take bleed air from the aircraft s engines to pass air through a filter first to remove particulates and then pass the air through the ASM containing hollow fiber membranes. In the lab, there will be a heating element provided to simulate the temperature of the bleed air that will be entering the ASM and analysis of the separated air will be analyzed by a Gas Chromatograph/Mass Spectrometer (GC/MS). The GUMS will separate the different compounds in the exit streams of the ASM and provide information on the performance of hollow fiber membranes. Hopefully I can develop ways to improve efficiency of the ASM. different types of jet fuel were analyzed and data was well represented on SAE Paper 982485. Data consisted of the concentrations of over 300 different hydrocarbons commonly found in JP- 8, Jet A, and JP-5 fuels. I researched the major hydrocarbons that has a concentration of greater than 50 parts per million and found the vapor pressure data coefficients for a specific temperature range. The coefficients were applied to Antoine s Equation and Riedel's Equation to calculate the vapor pressures for that specific hydrocarbon in the specific temperature range. With the vapor pressure data scientists can formulate a fuel composition that has a lower vapor pressure profile, therefore making jet fuels less flammable. work, learn how to operate and examine the data from Gas Chromatograph and Mass Spectrometer, and develop new ways in applying hollow fiber membrane technology to other areas of environmental engineering. The United States military currently uses air separation technology and their primary The other side of making air travel safer is to reformulate the fuel. Analyses of three My goal this summer is to learn about hollow fiber membrane technologies and how they

Huang, Stephen E.↗
DOE OSTI2023

High-Performance, Hybrid Polymer Membrane for Carbon Dioxide Separation from Ambient Air

The Department of Energy (DOE) seeks to develop carbon capture materials specifically tailored for Direct Air Capture (DAC) processes. Related to this, they require recipients to develop novel DAC materials such as: solvents, membranes, or sorbents that demonstrate high affinities or capacities for carbon dioxide (CO2) at concentrations typically available in air and at near ambient conditions. Toward this, InnoSense LLC (ISL) is developing High-Performance, Hybrid Polymer Membranes (HypoMemTM) for Carbon Dioxide Separation from Ambient Air. HypoMem consists of two major layers. The first layer is the active layer which contains the active ingredients that help to separate CO2 from ambient air. The second is the support layer that provides good mechanical support to have a free-standing membrane without interfering with the properties of the active layer.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2025

Ligand-Functionalized Polymer Membranes for Selective Ion Separations

Selective ion separations are central to technologies spanning water purification, resource recovery, and clean energy. Conventional polymer membranes, which rely on steric hindrance or Donnan exclusion, struggle to discriminate between chemically similar ions in high-ionic-strength environments. Ligand-functionalized membranes offer a transformative strategy by embedding molecular recognition directly into polymer matrices, enabling selective complexation and transport. Here, this Viewpoint highlights the structure–function relationships underlying ligand-mediated ion separation, emphasizing the interplay of dehydration penalties, ligand coordination, and nanoscale confinement. We discuss design principles, denticity, donor identity, rigidity, and spatial organization, alongside the permeability–selectivity trade-off, multicomponent effects, and stability challenges. Finally, we outline emerging strategies, from bioinspired ligands to computationally guided design, that chart a path toward next-generation membranes for precise and energy-efficient ion separations.

ions↗
DOE OSTI2021

Highly selective ion separations based on counter-flow electromigration in nanoporous membranes

Highly selective ion separations are vital for recovering important salts, and membrane-based techniques may enable environmentally friendly ion separations that operate continuously. This study demonstrates that simply opposing convective flow with electromigration in track-etched membranes leads to remarkable selectivities among monovalent ions. Because the membrane-pore diameters are orders of magnitude larger than the ion diameters, advection moves all ions at the same velocity, whereas electrophoretic velocities are proportional to ion mobilities. Thus during counter-flow cation electromigration, less mobile cations have lower electromigration velocity components and pass through porous membranes more rapidly than more mobile cations. Using membranes with 400 nm pores, counter-flow electromigration gives Li + /K + selectivities of 100 and Li + /Na + selectivities around 30 in mixed-salt studies. In this work, numerical simulations based on the extended Nernst-Planck equation agree with trends in experimental data and highlight the importance of high Péclet numbers, high current-to-flow ratios, and uniform current distributions for achieving high selectivities. Importantly, experimental separations give high selectivities at 0.3 M ionic strength and low Li + /K + ratios, which suggest these methods may also work in brine solutions. Nevertheless, energy costs for such separations are high.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Molecular design and fabrication of PIM-1/polyphosphazene blend membranes with high performance for CO 2 /N 2 separation

New polymeric blend membranes for CO 2 separation were synthesized based on insights from molecular dynamics simulation. A molecular-level structure-property relationship in polymers of intrinsic microporosity (PIM) based blend membranes, was investigated in detail computationally. Calculated local density profiles and energy of interaction of the blend membranes, composed of PIM-1 and various polyphosphazenes, showed that using the polyphosphazene with a higher concentration of ether side chains can improve the compatibility with PIM-1. Furthermore, based on the findings of computational studies, blend membranes were experimentally fabricated from PIM-1 and polyphosphazenes with various polyether side chain concentrations. Polyether concentration in polyphosphazenes was correlated with the film properties and gas transport performance of the blend membranes. Blend membranes showed very high CO 2 permeability (3100-5300 barrer) and improved CO 2 /N 2 selectivity (24-28), outperforming all other PIM-based blend membranes reported to date. Moreover, the CO 2 permeability performance of the blend membranes was tested 566 hours under real post-combustion flue gas from a coal-fired power plant, including CO 2 , N 2 , H 2 O, O 2 , SO x and NO x .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Amine functionalized supported ionic liquid membranes (SILMs) for CO 2 /N 2 separation

Supported ionic liquid membranes (SILMs), containing aprotic N-heterocyclic anion ionic liquids (AHA ILs) in an inorganic inert support, exhibit CO 2 /N 2 permselectivity values as high as 640 at 35.0 °C and 0.03 bar CO 2 , which represents conditions similar to post-combustion carbon capture (PCCC) from a natural gas power plant. A Fickian model fit to the experimental data estimates CO 2 permeability at direct air capture (DAC) conditions of 10,400 barrer and a CO 2 /N 2 permselectivity of 4000 for the best performing IL, triethyl(octyl)phosphonium 4-bromopyrazolide ([P 2228 ][4-BrPyra]). The most important criterion for high selectivity is a large equilibrium constant for binding between the IL and CO 2 , which results in high CO 2 solubility. ILs with smaller molar volumes and with no fluoroalkyl chains enhance N 2 rejection. As a result, low viscosity and high IL molar density also enhance CO 2 /N 2 permselectivity and CO 2 permeance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Protein drift-diffusion dynamics and phase separation in curved cell membranes and dendritic spines: Hybrid discrete-continuum methods

We develop methods for investigating protein drift-diffusion dynamics in heterogeneous cell membranes and the roles played by geometry, diffusion, chemical kinetics, and phase separation. Our hybrid stochastic numerical methods combine discrete particle descriptions with continuum-level models for tracking the individual protein drift-diffusion dynamics when coupled to continuum fields. We show how our approaches can be used to investigate phenomena motivated by protein kinetics within dendritic spines. The spine geometry is hypothesized to play an important biological role regulating synaptic strength, protein kinetics, and self-assembly of clusters. We perform simulation studies for model spine geometries varying the neck size to investigate how phase-separation and protein organization is influenced by different shapes. We also show how our methods can be used to study the roles of geometry in reaction-diffusion systems including Turing instabilities. Furthermore, our methods provide general approaches for investigating protein kinetics and drift-diffusion dynamics within curved membrane structures.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Scaling electrospray based additive manufacturing of polyamide membranes

Additive manufacturing based on electrospray printing has been demonstrated to fabricate polyamide membranes with separation properties similar to commercial membranes while also offering exceptional control of membrane thickness and roughness. In this work, we report on the scalability of the electrospray process to produce membrane leaves that are 10 times the area of membranes fabricated in literature through electrospray printing. The large membrane leaves exhibited salt rejection of >90% (at 2000 ppm feed salt concentration) and ∼0.7 LMH/bar flux, which is comparable to smaller printed membranes using the same process.

Additive manufacturing↗
DOE OSTI2025

Crossflow membrane filtration system for operando fouling characterization using transmission x-ray scattering

Membrane-based separations are widely used for wastewater treatment due to their low cost and efficiency. However, membrane fouling, which is the unwanted deposition or attachment of contaminants on membrane surfaces and/or within membrane pores, remains a major challenge as it increases the mass transfer resistance and reduces membrane productivity. Membrane fouling is typically probed by macroscopic performance metrics, such as flux decline, and ex situ characterization. However, this does not capture the membrane and fouling layer evolution under operating conditions, potentially masking important mechanisms and nonequilibrium pathways that impact fouling. Here, we present a remotely controlled crossflow membrane system and a custom membrane cell for operando fouling characterization using transmission small/wide angle x-ray scattering (SAXS/WAXS). This approach allows direct observation of the nanoscale changes occurring at the membrane surface during pressurized water treatment processes, enabling a new way to understand the connections between dynamic fouling behaviors and membrane performance. Nanoparticle fouling of porous membranes during ultrafiltration was investigated using operando SAXS, and mineral scaling of reverse osmosis membranes was investigated using operando WAXS. Furthermore, this system allows for tracking membrane fouling in real time and under realistic conditions, providing fundamental physical insights into how water chemistry and operating conditions affect macroscopic membrane performance. Moreover, this system opens the door for future in situ and operando studies, and it serves as a testbed for evaluating novel materials/processes for membrane-based separations.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Engineering surface charges of nanofiltration membranes to maximize Li + /Mg 2+ separation properties

Polyamide-based nanofiltration (NF) membranes are attractive for Li + /Mg 2+ separation for lithium recovery from salt brine (containing mainly Mg 2+ ). However, Li + and Mg 2+ have similar hydration radii, resulting in a low separation factor (SF Li/Mg ). Herein, we demonstrate that SF Li/Mg can be significantly enhanced by optimizing the membrane surface positive charges. This results in an unexpected maximum SF Li/Mg at a solution pH slightly below its isoelectric point (IEP). Specifically, NF270 membrane was surface-grafted with 2-(methacryloyloxy)ethyltrimethylammonium chloride (META) or polyethylenimine (PEI) using bio-adhesive dopamine, forming a thin, stable, charged layer (20–40 nm) on the surface. The effects of solution pH and surface modification on the surface zeta potential (ZP) and single- and mixed-salt Li + /Mg 2+ separation properties are thoroughly investigated. For example, the META grafting increases the ZP from 9.2 to 16 mV and SF Li/Mg by 130 % from 35 to 80 at pH 4, superior to the state-of-the-art commercial NF membranes. Furthermore, this surface modification occurs at ≈22 °C in aqueous solutions and can be utilized to enhance commercial modules for practical applications.

Li+/Mg2+ separation↗
DOE OSTI2022

Polymeric Microcapsules as Robust Mimics of Emulsion Liquid Membranes for Selective Ion Separations

Selective ion separations are increasingly needed to combat water scarcity, recover resources from wastewater, and enable the efficient recycling of electronics waste. Emulsion liquid membranes (ELMs) have received interest due to rapid kinetics, high selectivities, and low solvent requirements but are too unstable for industrial usage. Here, we demonstrate that polymeric microcapsules can serve as robust, solvent-free mimics of ELMs. As a proof of concept, we incorporated the copper-selective ligand Lix 84-I in the walls of microcapsules formed from a commercial polystyrene-b-polybutadiene-b-polystyrene triblock polymer. The microcapsules were formed from a double-emulsion template, resulting in particles typically 20–120 μm in diameter that encapsulated even smaller droplets of a dilute (≤0.5 M) H 2 SO 4 solution. Batch experiments demonstrated facilitated-transport behavior, with equilibrium reached in as little as 10 min for microcapsules with 1% ligand, and with ~15-fold selectivity for Cu 2+ over Ni 2+ . Furthermore, the microcapsules could be packed readily in columns for flow-through operation, thus enabling near-complete Cu 2+ removal in ~2 min under certain conditions, recovery of Cu 2+ by flowing through fresh dilute H 2 SO 4 , and reuse for at least 10 cycles. The approach in this work can serve as a template for using selective ligands to enable robust and simple flow-through processes for a variety of selective ion separations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

How Selective Transport Layer Improves Efficiency and Durability of Proton Exchange Membrane Fuel Cells

In any electrochemical device, the separator or membrane allows specific ions to transport but blocks electrons and other chemical species, enabling the electrochemical energy to be harvested. However, small amounts of undesired species are known to permeate through the membrane, reducing overall system efficiency and lifetime. An emerging concept called the “Selective Transport Layer” preferentially allows only protons to pass through but reduces the permeance of other species by a meaningful degree. Here, in this study, we demonstrate that a 60 nm thick graphene oxide composite layer can be very effective in reducing gas and ion permeation, even for a gas as small as H 2 , while not noticeably increasing proton transport resistance. In electrode and membrane accelerated stability tests, we show that both electrode and membrane durability are improved by a factor of two. Microscopy and mathematic simulations confirm that the graphene oxide composite is effective in blocking transport of dissolved Pt 2+ . The improved durability and reduced H 2 fuel crossover are expected to substantially reduce initial and operating costs of the fuel cell system. How this technology may affect other membrane-based electrochemical devices is also discussed.

Ngo, Phuong Quynh [General Motors, Pontiac, MI (Un↗
DOE OSTI2020

3D-Printed Membranes with a Zwitterionic Hydrogel Coating for More Robust Oil–Water Separation

Three-dimensional (3D)-printed membranes via stereolithography (SLA) are promising in oil–water separation, which is the key in the purification of industrial oily wastewater. To achieve gravity-driven oil–water separation, the membrane material needs to be simultaneously hydrophilic/oleophobic. However, most of the state-of-the-art materials for SLA do not meet the requirement. While water-adsorbing hydrogel is simultaneously hydrophilic/oleophobic and there have been reports on 3D printing of hydrogels in biomedical applications, the hydrogel is too soft for membrane application. Here, we report a simple approach to tackle the issue: a hydrogel coating on SLA-based plastic membranes. The coating is fabricated, using [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide as the zwitterionic monomer and acrylamide as the comonomer, via in situ polymerization on SLA-based plastic membranes. The contact angle tests and Fourier transform infrared spectrum show that such a membrane readily adsorbs water and becomes simultaneously hydrophilic/oleophobic. The oil–water separation tests indicate that the water-adsorbed membrane is highly efficient in gravity-driven oil–water separation in 31 repeating cycles. Our results indicate the great potential of 3D-printed membranes in oil–water separation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Above‐T g Annealing Benefits in Nanoparticle‐Stabilized Carbon Molecular Sieve Membrane Pyrolysis for Improved Gas Separation

Nanoparticles can suppress asymmetric precursor support collapse during pyrolysis to create carbon molecular sieve (CMS) membranes. This advance allows elimination of standard sol-gel support stabilization steps. Here we report a simple but surprisingly important thermal soaking step at 400 °C in the pyrolysis process to obtain high performance CMS membranes. The composite CMS membranes show CO 2 /CH 4 (50 : 50) mixed gas feed with an attractive CO 2 /CH 4 selectivity of 134.2 and CO 2 permeance of 71 GPU at 35 °C. Furthermore, a H 2 /CH 4 selectivity of 663 with H 2 permeance of 240 GPU was achieved for promising green energy resource-H 2 separation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗