Advanced Water Recycling for Space Missions via Photocatalytic Degradation and In Situ RONS Generation (AWaRDS)

Ensuring access to clean water is a critical challenge for long-duration space missions, where resupply is impossible and recycling wastewater—such as greywater, urine, and condensate—becomes essential. Current technologies like distillation and filtration are energy-intensive and poorly suited to microgravity and limited power. CNES, through the Spaceship FR project, is developing sustainable solutions for astronaut life support systems.

AWaRDS proposes an innovative approach combining photocatalytic degradation using iron oxide nanoparticles (NPs) and in situ generation of reactive oxygen nitrogen species (RONS) via in-liquid plasma discharge. The goal is to create a low-energy, chemical-free water recycling system for missions to the Moon, Mars, or space stations. This system integrates photocatalytic NPs with plasma-generated RONS, particularly hydrogen peroxide (H₂O₂), to degrade organic and inorganic pollutants efficiently. The technology not only supports space exploration but also offers potential for terrestrial water treatment, aligning with global sustainability goals.

Long-duration missions, including those under the Artemis program, require systems capable of treating organic contaminants like urea, phenol, bacteria, and viruses, as well as inorganic salts such as ammonium and chlorides. Microgravity complicates phase separation and catalytic reactions, adding to the technical challenges. Current systems on the International Space Station rely on energy-intensive distillation and filtration, which are prone to fouling. Advanced oxidation processes, like the Fenton reaction, provide alternatives but depend on externally supplied H₂O₂, which is impractical for space missions.

Iron oxide NPs act as effective photocatalysts by generating hydroxyl radicals through Fenton reactions under light irradiation, breaking down organics into carbon dioxide and water. These NPs are reusable due to their magnetic properties, reducing waste, and are compatible with UV/visible light, making them ideal for space habitats. Recent studies confirm their efficiency in degrading pollutants like methylene blue and phenol, as well as their scalability in closed systems.

In-liquid plasma discharge generates RONS, including H₂O₂, through electron impact and UV dissociation of water and oxygen. Catalysts like metal oxides enhance yields, and the process adapts well to microgravity, eliminating the need for stored chemicals. This method has already proven effective in treating urine by degrading urea and organic compounds without external additives.

The AWaRDS’s objectives include synthesizing and optimizing iron oxide NPs for maximum photocatalytic activity under UV/visible light, focusing on size, surface area, and magnetic properties. It also aims to develop a compact plasma reactor for in situ H₂O₂ generation, optimizing energy input and catalyst selection for microgravity conditions. Finally, the project seeks to integrate photocatalysis and plasma-generated H₂O₂ into a prototype system, testing its performance with NASA-standard wastewater simulants containing organic pollutants. Efficiency will be evaluated based on pollutant removal rates, energy and mass balance, and catalyst stability over multiple cycles.

The methodology involves three tasks: Task1 synthesizing and characterizing (TEM, XRD, BET surface area, and magnetic susceptibility) iron oxide NPs (Fe₃O₄/α-Fe₂O₃) under 10 nm, functionalizing them by different stabilizing agents or their surface modification (e.g., silica coating) or their inclusion into DLC matrix for stability and catalytic activity; Task2 designing a pin-to-pin electrode plasma reactor to maximize H₂O₂ production (target: 50–100 mg/L) by optimizing voltage amplitude, pulse width, pulse frequency, water flow rate, and water pH; and Task3 building an integrated prototype to test with wastewater simulants, analyzing performance via HPLC, TOC, and UV-Vis spectroscopy. Energy efficiency will be measured using electrical energy per order (EE/O) for pollutant degradation.

AWaRDS expects to deliver novel iron oxide catalysts optimized for space, a first-of-its-kind plasma- H₂O₂ system for microgravity, and significant energy and mass savings compared to current technologies. The project will enable longer missions with reduced resupply needs and offer terrestrial applications like portable water treatment for remote areas, disaster relief, or military use. Sustainability benefits include reduced chemical use, improved energy efficiency through solar/LED-driven processes, and a circular economy approach with reusable catalysts and minimal waste.

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For more Information about the topics and the co-financial partner (found by the lab!); contact Directeur de thèse - myrtil.kahn@lcc-toulouse.fr

Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online  before March 13th, 2026 Midnight Paris time!