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Completed Project (201 2 - 2013)
Advanced Water Purification System For In Situ Resource
Utilization Project
Center Innovation Fund: KSC CIF Program
Office Of The Chief Technologist ( OCT )
National Aeronautics and
Space Administration
of the chTef;
ABSTRACT
A main goal in the field of In Situ Resource Utilization is to develop technologies
that produce oxygen from regolith to provide consumables to an extraterrestrial
outpost. The processes developed reduce metal oxides in the regolith to produce
water, which is then electrolyzed to produce oxygen. Hydrochloric and
hydrofluoric acids are byproducts of the reduction processes, which must be
removed to meet electrolysis purity standards. We previously characterized
Nation, a highly water selective polymeric proton-exchange membrane, as a
filtration material to recover pure water ...Read more on the last page.
Project Technology Maturity
Technology Area:
Human Health, Life Support & Habitation Systems
TA06 (Primary)
Human Exploration Destination Systems TA07
(Secondary)
ANTICIPATED BENEFITS
To NASA unfunded & planned missions:
The success of this technology will reduce the cost of operating and maintaining ISRU
systems, enabling long-term deep-space missions.
To the commercial space industry:
Potential Customers: ISRU Environmental Control and Life Support System (ECLSS)
Space Power Systems
Read more on the last page.
Tech Port
For more information go to techport.nasa.gov.
Printed 4/22/2014
Advanced Water Purification System For In Situ Resource Utilization Project
U.S. states with work
Other Organizations
Performing Work
QinetiQ North America/ ESC
★ Lead center: Kennedy Space Center
DETAILED DESCRIPTION
The goal of In Situ Resource Utilization (ISRU) is to develop systems that allow for a long-term
human presence in space without the need for replenishment of materials from Earth. Lunar
regolith is of particular interest to ISRU researchers as potential source of oxygen for fuel and life
support. Hydrogen, which has been detected in the permanently-shaded regions of craters near
the lunar poles, can be used to reduce the metal oxides present in lunar regolith to produce water,
and via electrolysis, oxygen.
Prior to electrolysis, the water generated as an intermediate product must be treated to remove
absorbed hydrochloric and hydrofluoric acids, byproducts derived from trace amounts of fluoride
and chloride present in lunar regolith. In terrestrial applications, removal of chloride and fluoride
from water is a relatively trivial process due to the availability of consumable adsorbents, or by
utilizing other processes that require frequent regeneration. None of these processes are
applicable in the lunar environment, however, where resources are scarce.
We previously studied Nation, a commercially-available sulfonated tetrafluoroethylene polymer
membrane, as an ISRU filtration material because it can continuously facilitate water transport and
acid rejection without ...
MANAGEMENT
Program Executive:
Burton Summerfield
Program Manager:
Nancy Zeitlin
Project Manager:
Nancy Zeitlin
Principal Investigator:
Stephen Anthony
Co-Investigator:
Scott Jolley
TechPort
For more information go to techport.nasa,gov.
Printed 4/22/2014
2
Advanced Water Purification System For In Situ Resource Utilization Project
DETAILED DESCRIPTION (CONT'D)
the need for replacement or regeneration. While Nation showed promise as a filtration membrane, it was unable to
remove sufficient quantities of contaminants, particularly fluoride, and would require very large membrane contact
areas to generate appreciable quantities of clean water. Electrodialysis was chosen as an alternative water
purification process for the present study, due to its extensive industrial pedigree and demonstrated ability to rapidly
produce a clean water supply and concentrated waste brine.
Electrodialysis uses the principle of ion exchange. An electrodialysys stack contains alternating cation and anion
exchange membranes between two electrodes, with fluid-containing channels between each. Initially contaminated
feed (diluent) and initially clean waste (concentrate) solutions are passed through every other chamber as direct
current is applied across the electrodes. Anionic contaminants in the diluent solution diffuse across the anion
exchange membrane toward the anode (positively charged electrode), while cationic contaminants diffuse across
the cation exchange membrane toward the cathode (negatively charged electrode). The ionic species become
trapped in the concentrate solution, as the current directs anions toward cation exchange membranes through
which they cannot diffuse, and vice-versa.
When dissolved in water, HCI and HF dissociate into their individual ionic species, i.e. H+, Cl- and F-. As a strong
acid, HCI fully dissociates into its respective ions, while HF, a weak acid, only partially dissociates in an equilibrium
process. It is therefore expected that HCI will rapidly and nearly completely diffuse from the diluent to the
concentrate stream, while HF will diffuse into the concentrate stream more slowly, as the gradual removal of fluoride
ions will allow more HF to dissociate and be removed from the diluent stream. It is also expected that as the ion
concentration in the concentrate stream increases, osmotic pressure will drive water from the diluent to the
concentrate stream overtime, reducing the yield of clean water. As a result, experiments focused on optimizing both
the quantity of chloride and fluoride ions removed from the diluent stream, and the rapidity of ion transfer.
This project has successfully demonstrated the purification of high ion content water via the use of electrodialysis.
The knowledge gained during the evaluation of this process indicates that electrodialysis represents an excellent
choice as a primary water purification method in long duration exploration missions to locations such as the Moon
or Mars. Although this work has resulted in excellent progress towards developing a method that can be used to
purify water streams produced from extraterrestrial sources, much work needs to be done to establish the best
electrodialysis system for use in this environment. Further effort will need to be made to set up and evaluate an
automated system that can be operated in tandem with an ISRU water generation process.
TechPort
For more information go to techport.nasa.gov.
Printed 4/22/2014
3
Advanced Water Purification System For In Situ Resource Utilization Project
TECHNOLOGY DETAILS
TECHNOLOGY DESCRIPTION
An affordable and sustainable human exploration program will require the implementation of In
Situ Resource Utilization (ISRU) systems. One goal of ISRU systems is the production of oxygen
and hydrogen from regolith via reduction and electrolysis reactions. Water is produced as an
intermediate in this process, as are a number of undesirable contaminants, including hydrochloric
and hydrofluoric acids. Typical water purification materials require continuous regeneration or
replacement, and are not desirable in an environment where resources are limited.
This technology is categorized as a hardware system for other applications
• Technology Area
• TA06 Human Health, Life Support & Habitation Systems (Primary)
• TA07 Human Exploration Destination Systems (Secondary)
CAPABILITIES PROVIDED
This project has successfully demonstrated the purification of high ion content water via the use of
electrodialysis.
The knowledge gained during the evaluation of this process indicates that electrodialysis
represents an excellent choice as a primary water purification method in long duration exploration
missions to locations such as the Moon or Mars.
TechPort For more information go to teohport.nasa.gov. Printed 4/22/2014 4
Advanced Water
Purification System For In
Situ Resource Utilization
Technology Maturity
At Start: 2 | Current: 3 | At End: 3 |
Mill
Applied
Research
Development
Demo & Test
Advanced Water Purification System For In Situ Resource Utilization Project
IMAGE GALLERY
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TechPort
For more information go to techport.nasa.gov.
Printed 4/22/2014
Advanced Water Purification System For In Situ Resource Utilization Project
ABSTRACT (CONTINUED FROM PAGE 1)
from the contaminated solution. While the membranes successfully removed both acid contaminants, the removal
efficiency of and water flow rate through the membranes were not sufficient to produce large volumes of
electrolysis-grade water. In the present study, we investigated electrodialysis as a potential acid removal technique.
Our studies have shown a rapid and significant reduction in chloride and fluoride concentrations in the feed
solution, while generating a relatively small volume of concentrated waste water. Electrodialysis has shown
significant promise as the primary separation technique in ISRU water purification processes.
TechPort
For more information go to techport.nasa.gov.
Printed 4/22/2014
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