Extraction of water from the mesophase of a passive low-temperature liquid water storage system: Selection of a minimal energy process
zhaw
Lay summary
Phytantriol is a commercially available non-toxic aliphatic alcohol that is widely used in the cosmetics industry. Researchers at ETH Zurich and the University of Zurich showed that water can be maintained in a liquid state at temperatures as low as -120°C by mixing it with phytantriol in a simple thermal process. This produces a state of matter that exhibits properties between those of a solid and a liquid. This state is called a mesophase.
Later, upon an innovative initiative (water storage system for lunar life support and exploration) launched by Sirin Orbital Systems AG, a Zurich-based company for space applications, a team of researchers at the Zurich Institute of Applied Sciences (ZHAW) Institute of Energy Systems and Fluid Engineering (IEFE), at the ZHAW Institute of Materials and Process Engineering (IMPE), and at ETH Zurich, showed that up to 79 weight percentage of the water in the mesophase can be extracted again by distillation.
The fact that the mesophase remains in a liquid-like state and that repeated mixing and water extraction are possible, both can be exploited to design water storage systems for cold regions that do not require active heating of external installations like pipes, tanks, etc. This makes them energetically very efficient and enables easy transport through standard hydraulic networks. Challenges that are usually associated with water storage and supply in cold regions can then be removed or minimised. This includes pipe damage due to freezing, installing pipes in permafrost, or use of (chlorinated) indoor tanks with associated health risks.
If coupled with building-based wastewater recycling units, the technology can be used to design centralised closed-loop water storage and supply systems with (nearly) net zero water consumption for settlements and research stations in cold regions. Small units can potentially be designed to be portable. This minimises the need for overland water haulage to storage sites.
A key design objective is to minimise energy consumption. Significant reductions can be achieved by replacing distillation with a more energy-efficient extraction process. Candidates include pervaporation and nanofiltration. The latter is expected to be energetically more efficient. Both have been used before to separate other alcohols from water. Their potential to separate water and phytantriol will be evaluated in this project by a team of researchers at IEFE and IMPE. Challenges include the selection of adequate membranes and operating parameters. Performance measures include process efficiency, purity of the extracted water, process speed, system size, and system scalability. We expect to reach TRL4 at the end of this project. A techno-economic assessment will complete the assessments.
The technology holds the potential to revolutionise water supply systems for research stations, and improve water safety, increase water availability, and minimise water waste for settlements in polar regions that regularly suffer from poor freshwater quality, limited freshwater availability, or indeed run out of water regularly.
The work is financed by the Swiss Polar Institute under grant TEG-2024-002. This support is gratefully acknowledged. As the implementation partner, Sirin Orbital Systems AG continues its involvement in an advisory role, from the commercial perspectives.
Details
| Regional focus | Arctic |
| Location | |
| Funded amount | 74,700 CHF |
| Project dates | 7th April 2025 – 30th January 2026 |
| Category | SPI Technogrants |