New technology turns space urine into plant fertilizer

On the way to ourCredit: Luca Oleastri/ Adobe Stock / Big Thinking

In science fiction, they got it all: ancient inhabitants of Earth roaming the galaxies in massive space stations that waste nothing – everything, and everyone, is recycled. Now, however, there is still a lot to be discovered. Real-world solutions must be invented that can combine to create the enduring closed environments that will be necessary for spaceships and space colonies, not to mention the unwelcoming terrestrial environments that we hope to explore.

Researchers from Tokyo University of Science, led by Norihiro Suzuki, have just published a study in the form of a letter in New Journal of Chemistry. It offers an innovative system for bypassing ammonia-based liquid fertilizer from human urine, a win-win system that would simultaneously treat waste while benefiting agriculture.

Go aloneCredit: Luca Oleastri/ Adobe Stock / Big Thinking

In the past, we have built communities in areas that provide the resources we need to support us. When we needed to grow food, we populated places that have water, land on which to grow food and raise livestock, a decent climate, enough space to live, etc. As we leave such a comfortable environment, it all comes out of the airlock. As it is, all we have will be whatever we bring with us when we step out among the stars.

One of the most successful types of fertilizers has traditionally been nitrogen-rich animal waste. With this in mind, the Suzuki team worked on the production of ammonia, composed of nitrogen and oxygen, derived from the compound urea found in urine.

says Suzuki, “I joined the ‘Space Agriteam’ involved in food production, and my research specialization is in physical chemistry; Therefore, I had the idea of ​​”electrochemically” making a liquid fertilizer. “

“This process is interesting from the point of view of making a useful product,” says Suzuki, “ie ammonia from waste, ie from l urine, using common equipment at atmospheric pressure and room temperature. “

Credit: Suzuki, et al./New Journal of Chemistry

Researchers’ experiments have so far used artificial urine.

The electrochemical process invented by scientists works at room temperature.

On the one hand, a reaction cell contained both 50 milliliters of an artificial urine sample and a boron-doped diamond electrode (BDD) in a titanium oxide photocatalyst that was continuously agitated throughout the process. process. On the other, a counter-cell in which a platinum electrode was immersed in salt water. When a constant current of 70 mA was introduced into the BDD electrode, the urea oxidized and formed ammonia atoms.

As part of the experiment, the researchers also exposed the BDD submerged in the photocatalyst to light to see if it affected the process, and found that it actually resulted in reduced oxidation of the ammonia.

Then, says Suzuki, “We plan to perform the experiment with real urine samples, as it contains not only primary elements (phosphorus, nitrogen, potassium) but also secondary elements (sulfur, calcium, magnesium) which are vital for plant nutrition.! “

University of Tokyo Agriteam space is part of the school Space Colony Research Center. Obviously, agriculture in space is a key element in developing the future of humanity off the planet. Their goal is to find technological solutions for the development of a safe and sustainable space agriculture that can thrive in a totally closed environment.

The potential of the researchers’ new invention is clear to Suzuki, who predicts “that it will prove useful in maintaining a long-term stay in extremely closed spaces such as space stations.”

Leon E. Hill

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