Innovative modified zeolites for molecular decontamination in space
Taking advantage of innovative modified zeolites to trap volatile organic compounds (VOCs) detrimental to satellites embedded optics, the University of Haute Alsace (UHA) in Mulhouse, France, devised a method allowing to keep the sensors and optics of NASA’s Curiosity rover clean. Thanks to their microporous properties, this patented modified zeolites can also be used to trap bad odors in sewage treatment facilities, or to depollute air in hospitals.
The performance of embedded instruments within satellites, such as optic sensors can be greatly reduced by molecular contamination (fog and OCVs). In order to prevent the formation of condensation on embarked CCD sensors, research began in 1994 with the Wide Field / Planetary Camera 2 project (WFPC-2). Zeolite 13X was first identified by NASA and allowed decreasing contamination on the camera by half. In 2001, CNES (French National Center for Space Studies) and the University of Haute Alsace (UHA) investigated the molecular decontamination subject and developed a method for trapping VOCs using zeolites. Zeolites are microporous minerals belonging to the group of silicates. Their adsorption capacity depends on the size of the pores and the Si/Al molar ratio. This research led to a CNES-CNRS-UHA patent (Br. Fr. 2917645 A1 20081226, 2008).
Innovations & Advantages
Conventional methods employed for satellite decontamination include pre-degassing under vacuum, thorough cleaning of the instruments and restrictions on the construction materials used on the satellite. These methods have a limited efficiency and are costly in time and money. Moreover, pre-degassing does not prevent contamination during the launch. Instead, the adsorption of VOCs using zeolites under the form of a film allows a facilitated installation within satellites, and remains efficient throughout the lifetime of the instruments. Thanks to their microporous properties, zeolites can also be used to trap bad odors in sewage treatment facilities, or to depollute air in hospitals.
Current and Potential Domains of Application
Zeolites can be used as molecular adsorbents. The domains of application include satellite sensors decontamination as well as air, water and soils decontamination. Zeolites can therefore be used to trap bad odors in sewage treatment facilities, or to depollute air in hospitals. Apart from decontamination applications, zeolites can be used for ion exchange, liquid or gaseous separation and catalysis. They can also store and restore energy by transforming interfacial energy into mechanical energy.