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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.

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5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Efficacy of FTIR Analysis in Determining CO2 Loading on Diglycolamine

In support of advanced air revitalization technologies to enable human spaceflight beyond low earth orbit, performance studies have been conducted using a liquid amine, Diglycolamine (DGA) between teams at NASA's Johnson Spaceflight Center (JSC) and Ames Research Center (ARC). Liquid amines have been used in regenerable earth-based systems to remove CO2 from industrial systems as well as for closed-environment air revitalization because they can be regenerated at lower temperatures than solid sorbent systems. As an additional advantage to solid sorbent-based systems, liquid sorbents can be cycled between an adsorbing contactor and degassing chamber, thereby reducing system complexity by operation in a continuous loop. In an effort to inform a regeneration system design for micro-gravity applications, ARC has performed a number of tests to characterize the degas mechanics of DGA. In order to accurately measure the amount of CO2 captured or released by the amine, methods such as gravimetric weighing and chemical desorption are reasonable, however the first iteration test setup for a scaled down degas system required analysis on small sample sizes. Fourier-transform infrared spectroscopy (FTIR) analysis was experimentally evaluated to analyze CO2 concentration because it can produce measurements with sample sizes on the order of 100's of μL. Calibration against chemical desorption showed relatively good correlation and test data showed reasonable adherence to expected trends, however more extensive testing should be conducted to fully validate the usage of FTIR to determine CO2 loading on DGA.

Diglycolamine↗
NASA NTRS2018

Efficacy of FTIR Analysis in Determining CO2 Loading on Diglycolamine

In support of advanced air revitalization technologies to enable human spaceflight beyond low earth orbit, performance studies have been conducted using a liquid amine, Diglycolamine (DGA) between teams at NASA?s Johnson Spaceflight Center (JSC) and Ames Research Center (ARC). Liquid amines have been used in regenerable earth-based systems to remove CO2 from industrial systems as well as for closed-environment air revitalization because they can be regenerated at lower temperatures than solid sorbent systems. As an additional advantage to solid sorbent based systems, liquid sorbents can be cycled between an adsorbing contactor and degassing chamber, thereby reducing system complexity by operation in a continuous loop. In an effort to inform a regeneration system design for micro-gravity applications, ARC has performed a number of tests to characterize the degas mechanics of DGA. In order to accurately measure the amount of CO2 captured or released by the amine, methods such as gravimetric weighing and chemical decomposition are reasonable, however the initial design for a scaled down degas system required analysis on small sample sizes. In order to accomplish CO2 loading measurements with a sample size of approximately 500µL, Fourier-transform infrared spectroscopy (FTIR) was used. Calibration against acid decomposition showed relatively good correlation and test data showed reasonable adherence to expected trends, however more extensive testing should be conducted to fully validate the usage of FTIR to determine CO2 loading on DGA.

Diglycolamine↗
NASA NTRSDate not supplied

Diglycolamine Material Compatibility through Mechanical Testing

One promising candidate for use as a liquid sorbent in air revitalization technologies is a mixture of diglycolamine and water. This solution can react heavily with certain materials, putting a constraint on what materials can be used when designing and operating a liquid amine air revitalization system. Initial testing on materials has been done in the Air Revitalization labs at NASA Ames Research Center (ARC) through dunk testing of materials and physically checking for swelling, cracking, or any sort of corrosion of the material at hand. While this approach allowed for a quick way of material testing, a more thorough approach is favorable to allow for a database of compatible materials and their properties after contact with the solution for extended periods of time to be compiled. With this database, an air revitalization system intended for long-duration space flight can be designed and operated with confidence that the materials chosen will not degrade and need to be replaced over time.

Tiago Faria Costa↗
DOE OSTI2025

Impact of Ligands on the Ion–Ion Selectivity of Ligand-Appended-Pillar[ n ]arene Channels

Ligand-appended pillar[5]arene (LAP) channels are emerging as a promising platform for ion-selective membranes. In this study, we investigated the ion selectivities of three LAP channels functionalized with distinct ligands: diglycolamine, carbamoylmethyl phosphine oxide, and propionamide phosphonic acid. These ligands were chosen based on their demonstrated affinities for lanthanides in solvent extraction studies. We examined the selectivity of each channel toward a series of monovalent, divalent, and trivalent ions: Li + , Na + , K + , Mg 2+ , Ca 2+ , La 3+ , Eu 3+ , and Yb 3+ . To quantify ion-channel interactions and the energetics of translocation, we computed the potential of mean force (PMF) profiles for each ion. These PMFs were subsequently recast into permeability coefficients, enabling a direct evaluation of ion permselectivity. Our results reveal distinct selectivity patterns governed by the chemical nature of the appended ligands. The diglycolamine-functionalized channel exhibits strong interactions with monovalent ions, leading to replication of the Li + bulk hydration shell within the channel. This promotes preferential transport Li + ions while effectively excluding divalent and trivalent species. In contrast, the carbamoylmethyl phosphine oxide-functionalized channel displays a reduced selectivity between monovalent ions while similarly exhibiting an effective rejection of divalent and trivalent ions. This arises from steric hindrance around channel-lining oxygens imposed by the ligand's bulky phenyl groups which limits heavy ion coordination and promotes retention of hydration shells effectively increasing effective ion size. The propionamide phosphonic acid-functionalized channel exhibits a different trend, favoring ions with lower hydration free energies, with K + ions showing enhanced permeation. These findings highlight the critical role of ligand-ion interactions in modulating ion selectivity within LAP channels. In particular, the strong coordination exhibited by diglycolamine and propionamide phosphonic acid ligands significantly influences the ion transport energetics and selectivity profiles.

hydration↗
NASA NTRSDate not supplied

Design for an Integrated Open-Loop System for Carbon Dioxide Removal using Liquid Amine

Manned Space missions require maintaining a safe environment for the crew that can both sustain a breathable atmosphere and remove pollutants. Carbon dioxide, while not toxic in low concentrations, accumulates as crew members work and breath and can eventually affect the crew’s health. Therefore, a constant, passive system to remove the carbon dioxide build up is necessary for long-term missions. Currently, the prevailing liquid sorbent used in submarines and industrial flue gas utilizes the primary amine, monoethanolamine (MEA), to capture, transfer, and remove carbon dioxide from air. Diglycolamine (DGA) is an alternate primary amine that has similar performance and less volatility. It is currently being studied at Ames Research Center (ARC) and is the primary candidate for the operation of the sub-scale liquid amine test stand. The test stand is used to investigate liquid flow and liquid gas interfaces to assist in a system design for microgravity applications. The test stand includes a wedge design utilizes capillary action to hold the liquid while allowing gas-liquid interaction for carbon dioxide transfer. These wedge trays are placed in a contactor unit to remove carbon dioxide from the air stream, a degasser unit to replenish the liquid amine, and a capillary condensing heat exchanger (CCHX) to recapture water lost in the degasser unit. Nominal operating conditions for the contactor are a gas flow rate of 26scfm enriched with pure CO2 to 2600ppm and a liquid mixture of 65/35 vol% DGA/H2O at 0.65mL/min while the degasser was operated at 100°C and 1 atm. This paper discusses the challenges and limitations of a fully integrated system which will influence the design of a new subscale test stand.

Adrian Cortez↗