An electrolysis system that does not require pure water can change the game in terms of exploration.
Water and Mars, there is good news and not so good news. The good news: There is water on Mars! Not so good news?
There is water on Mars.
The Red Planet is very cold; the unfrozen water is probably filled with salt from the earth’s Mars, which lowers the freezing temperature.
You cannot drink salt water, and the usual methods of using electricity (electrolysis) require the removal of salt to break down oxygen (to breathe) and hydrogen (to get fuel); a heavy and costly endeavor in a harsh and dangerous environment.
However, if oxygen and hydrogen were to be expelled directly from the brine water, the electrolysis process of the brine would be much more complicated and expensive.
Engineers at the McKelvey School of Engineering at Washington University in St. Louis have developed a system that does just that. Their research was published today Proceedings of the National Academy of Sciences (PNAS).
The research team, led by Vijay Ramani, Roma B. and Raymond H. Wittcoff, University Professors in the Department of Energy, Environment and Chemical Engineering, did not validate the salt electrolysis system only under typical ground conditions; the system was studied in a simulated Martian atmosphere -33ºF (-36ºC).
“Mars’ electrolytic braces radically alter the logistical calculation of missions to Mars and beyond, ”Ramani said. “This technology is equally useful on Earth as a viable source of oxygen and fuel that opens up the ocean.”
In the summer of 2008, NASAPhoenix Mars Lander “touched and tasted” the water on Mars, the vapors of molten ice extracted from the earth. Since then, the European Space Agency’s Mars Express has found several underground ponds that remain in a liquid state due to the presence of magnesium perchlorate – salt.
To live on Mars (even temporarily), not to mention return to Earth, astronauts will have to manufacture some necessities in the Red Plan, including water and fuel. NASA’s Perseverance vehicle is now on its way to Mars, carrying instruments that will use high-temperature electrolysis. However, the Mars Oxygen Resource Use Experiment (MOXIE) will only produce oxygen from carbon dioxide in the air.
The system developed in Ramani’s lab can produce 25 times more oxygen than MOXIE using the same amount of power. It also produces hydrogen, which can be a fuel for astronauts to travel home.
“Our new brine electrolyzer has a lead ruthenate pyrochloride anode developed by our team along with a platinum carbon cathode,” Ramani said. “These carefully designed components, while optimally using the usual principles of electrochemical engineering, have achieved great performance.”
Careful design and a special anode allow the system to operate without having to heat or purify the water source.
“Paradoxically, perchlorates dissolved in water, called impurities, contribute to an environment like Mars,” said Shrihari Sankarasubramanian, a researcher at the Ramani group and the first author of the article.
“They prevent water from freezing,” he said, “and they also improve the performance of the electrolyzer system by reducing electrical resistance.”
Typically, water electrolyzers use highly purified and deionized water, which increases the cost of the system. Systems that can operate with “subtype” or salt water, such as technologies demonstrated by the Ramani group, can significantly improve the economic value of electrolyzing water everywhere – even here on planet Earth.
“After proving these electrolyzers under stringent Mars conditions, we plan to deploy them to much softer conditions on Earth to produce hydrogen and oxygen to feed salt or brackish water, for example through seawater electrolysis,” said Pralay Gayen Ramani of the postdoctoral research association and the first co-author of this study. also.
Such applications can be useful in the field of defense, such as generating oxygen in submarines, e.g. It could also provide oxygen while exploring unexplored environments in the deep sea closer to home.
The underlying technologies that enable the brine electrolyzer system must be patented through the Office of Technology Management and licenses are available at the university.
Reference: November 30, 2020, Proceedings of the National Academy of Sciences.