ZEOLITE CRYSTAL GROWTH (ZCG)
Research Area: Materials Science
Expedition(s): 4-6
Principal Investigator(s): ● Albert Sacco, Jr, PhD, Texas Tech University, Lubbock, Texas
RESEARCH OBJECTIVES
The ZCG investigations examined how subtle changes in the chemical formulation affected
nucleation and growth of zeolite crystals. The microgravity environment allowed researchers to
grow higher-quality crystals. These crystals have a number of useful commercial applications as
catalysts and absorbents.
EARTH BENEFITS
The 3-dimensional structure of a zeolite crystal allows it to act as a sieve to selectively filter
certain chemicals in applications such as petroleum processing. Larger crystals allow
researchers to better define the structure and understand how it works, with a goal of
producing improved crystals on Earth. Improved zeolites may have applications in storing
hydrogen fuel, reduction of hazardous by-products from chemical processing, and more
efficient techniques for petroleum processing.
SPACE BENEFITS
Multifunctional Titanosilicates may be used for Absorbtion/Separation of Carbon Dioxide and
Water for Portable Life Support System (PLSS) A lightweight fully regenerative water/carbon
dioxide separator is a necessity for long duration,
deep space exploration. One critical component
is a regenerative water/carbon dioxide separator
that can capture the water for recovery, and
either capture and recover the carbon dioxide or
vent it to a low pressure environment (i.e., Mars).
Titanosilicates can be adjusted both with respect
to size and shape, and with respect to pore size.
These have been used commercially to separate
water and carbon dioxide. By varying size and
shape the pressure drop is minimized, while
variations in the pore size for a given structure
allows the customization of these high surface
area (~500 m2/g) adsorbents. As a potential
added benefit, the constituents to make
titanosilicates can be obtained on the lunar surface from ilmenite (iron titanium oxide which
crystallizes in igneous rocks out of magma in the bottom layers) reduction and silicates
(compound of silicon and oxygen).
RESULTS
ZCG produced zeolite crystals with a high degree of crystalline perfection in microgravity.
During ISS Expedition 6, 19 zeolite samples were mixed and incubated. These samples were
NASA Image: ISS005E19055 - View of Astronaut
Peggy Whitson, Expedition Five Flight Engineer,
as she places a cartridge into the Zeolite Crystal
Growth (ZCG) experiment located in the U.S.
Laboratory/Destiny on ISS.