New Water Treatment Technology to Potentially Help Mars Explorers
A group of researchers of the University of California, Riverside developed a chemical that can be adapted in water treatment and potentially facilitate Mars exploration. A molybdenum fertilizer based catalyst can extract over 99% of harmful perchlorates from water and soil. It can potentially clean Martian soil and help produce oxygen for future Mars explorers.
The Hidden Danger of Perchlorates
Perchlorates can be defined as a group of chemical compounds that contain the perchlorate ion (-ClO₄). The ion consists of one atom of chlorine and four atoms of oxygen. Due to high oxygen content, perchlorate is a powerful oxidizer. This is why it is widely used in solid rocket fuel, explosives, fireworks, and signal flares. It is also a byproduct in some herbicides and disinfectants.
Perchlorates are mostly manufactured, however, certain compounds of this group can be found in soils in Latin America. Due to its ubiquity in industrial goods and soil, perchlorate is a common contaminant. Large amounts are washed off fields and dumped into aquifers with wastewaters. Their oxidizing properties make them harmful for living beings. The ion is accumulated in plant fibers and hampers growth. In the human body perchlorate affects the thyroid and may be the cause of severe dysfunctions and diseases.
The New Compound for Water Treatment
In 2021, Changxu Ren, a doctoral student, and Jinyong Liu, an assistant professor of chemical and environmental engineering at UC Riverside, managed to develop a way to eliminate perchlorate in water under natural conditions.
The scientists noted that anaerobic microbes can reduce perchlorate with molybdenum in their enzymes and harvest energy from the reaction. Taking inspiration from nature, they succeeded in synthesizing a similar compound in the lab. They were not the first to try and construct a metal-based catalyst for water treatment, but they were the first ones to succeed in making one compatible with water.
“Previous efforts in constructing a chemical molybdenum catalyst for perchlorate reduction have not been successful. Many other metal catalysts either require harsh conditions or are not compatible with water.” – Jinyong Liu, assistant professor of chemical and environmental engineering at UC Riverside.
The new technology enabled the researchers to eliminate perchlorate in water in one simple step. By mixing a commonly used fertilizer called sodium molybdate, a molybdenum binding compound called bipyridine, and a common hydrogen-activating catalyst called palladium on carbon, they constructed a powerful catalyst that reduces up to 99.99% of perchlorate into chloride regardless of the initial perchlorate concentration.The new chemical is expected to be utilized in water treatment to remediate contaminated groundwater and wastewater, as well as in making Mars habitable.
Perchlorates and Life on Mars
Mars has long fascinated Earth dwellers as a place for a potential extraterrestrial colony. Unlike Earth, the soil on Mars contains excessive amounts of perchlorate. Such soil composition makes it unsuitable for growing food: the produce grown there would be unsafe to eat. Apart from that, perchlorate in Martian dust can be hazardous for explorers, too.
Current methods of removing perchlorates from water require harsh conditions which Mars explorers would struggle to create. The new water and soil treatment technology based on the molybdenum catalyst shall serve as a simple and manageable alternative. Inventions like this gradually bring space colonization closer to reality.
“A convenient catalytic reduction system may help harvest oxygen gas from perchlorate washed from the Martian soil when the catalyst is coupled with other processes,” – Jinyong Liu, assistant professor of chemical and environmental engineering at UC Riverside.