|
|||||
|
|
Investigation of the water sorption properties of Mars-relevant micro- and mesoporous minerals |
|
| Authors: | Jochen Jänchen David L Bish Helmut Stach |
| Institution: | a Technische Fachhochschule Wildau (University of Applied Sciences), Bahnhofstraße, D-15754 Wildau, Germany b Indiana University, 1001 E 10th St., Bloomington, Indiana 47405, USA c DLR Institute of Planetary Research, Rutherfordstr. 2, D-12489 Berlin, Germany d ZeoSys GmbH, Volmerstr. 13, D-12489 Berlin-Adlershof, Germany |
| Abstract: | Encouraged by recent results of the Mars Odyssey spacecraft mission and the OMEGA team (Mars Express) concerning water in equatorial latitudes between ±45° on Mars and the possible existence of hydrated minerals, we have investigated the water sorption properties of natural zeolites and clay minerals close to martian atmospheric surface conditions as well as the properties of Mg-sulfates and gypsum. To quantify the stability of hydrous minerals on the martian surface and their interaction with the martian atmosphere, the water adsorption and desorption properties of nontronite, montmorillonite, chabazite and clinoptilolite have been investigated using adsorption isotherms at low equilibrium water vapor pressures and temperatures, modeling of the adsorption equilibrium data, thermogravimetry (TG), differential scanning calorimetry (DSC), and proton magic angle spinning nuclear magnetic resonance measurements (1H MAS NMR). Mg-sulfate hydrates were also analyzed using TG/DSC methods to compare with clay mineral and zeolites. Our data show that these microporous minerals can remain hydrated under present martian atmospheric conditions and hold up to 2.5-25 wt% of water in their void volumes at a partial water vapor pressure of 0.001 mbar in a temperature range of 333-193 K. Results of the 1H MAS NMR measurements suggest that parts of the adsorbed water are liquid-like water and that the mobility of the adsorbed water might be of importance for adsorption-water-triggered chemistry and hypothetical exobiological activity on Mars. |
| Keywords: | Mars surface Mineralogy Geochemistry |
| 本文献已被 ScienceDirect 等数据库收录！ | |