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Zeolite Crystal Growth (ZCG)
07.31.09

Overview | Description | Applications | Operations | Results | Publications | Images

Experiment/Payload Overview

Brief Summary

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.

Principal Investigator

  • Albert Sacco, Jr., Ph.D., Northeastern University, Boston, MA

    • Co-Investigator(s)/Collaborator(s)

    Information Pending

    Payload Developer

    Northeastern University, Center for Advanced Microgravity Materials Processing, Boston, MA

    Sponsoring Agency

    National Aeronautics and Space Administration (NASA)

    Expeditions Assigned

    |4|5|6|

    Previous ISS Missions

    ZCG has been performed successfully on STS-50, STS-57 and STS-73. Unfortunately due to the loss of Space Shuttle Columbia (STS-107) during re-entry into Earth's atmosphere, the ZCG samples processed on STS-107 were not available for processing.

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    Experiment/Payload Description

    Research Summary

    • This investigation examined how microgravity affects formation and growth of zeolite/zeotype crystals. The three-dimensional structure of a zeolite crystal allows it to act as a molecular sieve to selectively filter certain chemicals in applications such as petroleum processing.


    • ZCG furnace provided larger zeolite crystals with fewer defects to characterize their structures, establish structure property relationship, and better understand their sorption, ion exchange, and catalytic performance in order to design new and better materials for use in traditional as well as new applications.

    Description

    Zeolites, which are mineral crystals of aluminosilicates, have a rigid crystalline structure with a network of interconnected tunnels and cages that is similar to a honeycomb. A sort of mineral sponge, zeolites have the ability to absorb and release liquids and gases such as petroleum or hydrogen while remaining as hard as rock.

    Zeolites are important for many industrial processes, and are used as commercial ion exchangers, adsorbents, and catalysts. Virtually all the world's gasoline is produced or upgraded using zeolites. Zeotype ETS titanosilicates contain natural quantum wires in their structures, which are of great potential in electronic and optical applications and in photochemistry. There is insufficient understanding of how zeolite and zeotype materials grow, however, making it difficult for scientists to independently control structure characteristics such as size, morphology, and purity. Growing zeolite crystals in microgravity minimizes the role of convection and sedimentation, and may allow production of crystals with fewer defects.

    The Zeolite Crystal Growth (ZCG) furnace, which was designed for the and derived from earlier shuttle models, can grow zeolites, zeotype titanosilicate materials, ferroelectrics, and silver halides, all materials of commercial interest. The unit consists of a cylinder-shaped furnace, the Improved Zeolite Electronic Control System (IZECS), which includes a touchpad and data display as well as autoclaves. Two precursor growth solutions are placed into each autoclave, which mix during their stay in the furnace.

    Zeolite Beta was grown from precursor solutions of sodium aluminate and colloidal silica heated to 403 K (130 degrees C) on station. The samples were characterized by X-ray diffraction to determine the crystal structure. The performance of zeolite Beta as a Lewis acid catalyst was evaluated using a standard set of chemical reduction reactions known as the Meerwein-Pohhdorf-Verley (MPV) reactions.

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    Applications

    Space Applications

    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).

    Earth Applications

    The three-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.

    Zeotype ETS titanosilicate crystals contain linear, monatomic...Ti-O-Ti-O-Ti chains that can behave as quantum wires. Improved ETS crystals with controlled morphology and size, minimal intergrowth, and fewer lattice defects would have greater potential for quantum wire applications. Thus, improved ETS crystals are of great potential in electronic, optical and sensor applications, and in photochemistry. Zeolite and zeotype materials have great potential for commercial applications. Their shapes form complex, open frameworks that act as absorbents or filters, and they can be used in diverse ways: as absorbents for oil spills; to control household odors; to filter ammonia from municipal wastewater; and as a growth medium for hydroponic horticulture. They have been suggested as nuclear waste scavengers and quantum confinement hosts for semiconductor materials. Arrays of natural quantum wires in ETS titanosilicates may find applications in thermoelectric and photovoltaic devices.

    The Center for Advanced Microgravity Materials Processing also is studying other uses for improved zeolites, including detergents, optical cables, gas and vapor detection for environmental monitoring and control, and chemical production techniques that significantly reduce hazardous by-products.

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    Operations

    Operational Requirements

    The ZCG experiments are vibration sensitive, so they are housed in EXPRESS Rack 2 (lockers 1 and 2) where they can be supported by the Active Rack Isolation System (ARIS). While the experiments are in process, the ZCG furnace requires constant power and auxiliary backup power. The unit is powered-down when the experiments are completed.

    Operational Protocols

    Two precursor growth solutions are loaded into each metal-housed autoclave before flight. After unpacking the autoclaves, the crew spins them to force any bubbles to the center of the solution where they join into a single large bubble. This reduces the probability that bubbles will affect the crystallization. (This step, devised by Expedition 6 Commander Kenneth Bowersox, was added to standard procedures during Increment 6.) The crew performed a test mix in a clear autoclave to determine the correct mixing protocol. They recorded their findings into the IZECS, which located on a mounting plate in the EXPRESS Rack and connected to the Furnace unit. IZECS used the data to mix the solutions, powered by a motor fitted to the autoclaves. After the solutions are mixed, the furnace started to heat the samples. Crystallization occured over several hours. Using the IZECS front touch pad, the crew monitored autoclave tubes 1, 7, 8, and 19, and recorded the data in a log. Data is also downloaded from the IZECS, via the EXPRESS Rack, to the Station computer, and then downloaded to the ground-based research team. The duration of the processing is dependent upon the sample solution. Once processing is complete the samples will be allowed to cool to touch temperature, unloaded from the furnace and stowed. After ZCG autoclaves were returned to Earth, the investigators used X-ray crystallographic techniques, field emission scanning and/or transmission electron microscopy, atomic force microscopy, thermal analysis, elemental analysis, infrared and/or Raman spectroscopy, particle size analysis techniques, temperature programmed desorption of ammonia, and catalytic test reactions to analyze the crystals.

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    Results/More Information

    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 returned to Earth at the conclusion of Expedition 6 and sent back to the principal investigator for analysis.

    Results from the samples mixed on ISS suggest that the Lewis acid catalytic sites are altered in microgravity, as indicated by lower catalytic activity in the MPV probe reaction compared to Earth-grown zeolite. This further suggests that the control of fluid dynamics during crystallization may be important in making better industrial catalysts. Although space-grown zeolites had the same particle morphology and identical surface framework as zeolites grown on Earth, the average zeolite size of the space-grown crystals was 10% larger than crystals grown on Earth (Akata et al. 2004).

    Larger zeolite crystals allow researchers to better define the structure and understand how they work, with a goal of producing improved crystals on Earth. Improved zeolites may have applications in storing hydrogen fuel, reduction of hazardous byproducts from chemical processing, and more efficient techniques for petroleum processing.

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    Related Web Sites
  • NASA Fact Sheet
  • Center for Advanced Microgravity Processing

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    Publications

    Results Publications
    • Akata B, Yilmaz B., Jirapnogphan SS, Warzywoda J, Sacco Jr. A. Characterization of zeolite Beta grown in microgravity. Microporous and Mesoporous Materials. 2004 ;71:1-9.

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    Related Publications
    • Nurcan B, Harpster J, Matson RA, Sacco A Zeolite Crystal Growth Facility for Solution Crystal Growth on the International Space Station AIAA ;AIAA 2001-4949. 2001
    • Akata B, Sacco Jr. A. Control of product selectivity over terrestrial/control and flight zeolite Beta in the Meerwein-Ponndorf-Verley-Oppenauer Reactions. Extended Abstracts North American Catalysis Meeting, Philadelphia, PA. Jun, . 2005
    • Akata B, Warzywoda J., Sacco A. Gas phase Meerwein-Ponndorf-Verley reaction: Correlation of the 3665 cm-1 IR band with the cis-alcohol selectivity. Journal of Catalysts. ;222(2):397-403. 2003
    • Manning MP, Miller RP, McLaughlin G, Sacco A, Akata B, Bazzana S, Jirapongphan SS, Mendonza AM, Yilmaz B, Warzywoda J, Sacco Jr. A. Zeolite Crystal Growth on the International Space Station. Proceedings of the 14th International Zeolite Conference. ;ISBN: 0-958-46636-X, 147-154. 2004
    • Corma A, Diaz-Cabanas MJ, Martinez-Triguero J, Rey F, Rius J. A large-cavity zeolite with wide pore windows and potential as an oil refining catalyst. Nature. ;418(6897):514-517. 2002
    • Coker EN, Jansen JC, Direnzo F, Fajula F, Martens JA, Jacobs PA, Sacco Jr. A. Zeolite ZSM-5 synthesized in space: catalysts with reduced external surface activity. Microporous and Mesoporous Materials. ;46: 223-236. 2001
    • Coker EN, Jansen JC, Martens JA, Jacobs PA, DiRenzo F, Fajula F, Sacco Jr. A. The synthesis of zeolites under microgravity conditions: a review. Zeolites. ;23:119-136. 1998
    • Warzywoda J, Bac N, Sacco Jr A. Synthesis of large zeolite X crystals. Journal of Crystal Growth. ;204:539-541. 1999
    • Seo JS, Whang D, Lee H, Jun SI, Oh J, Jeon YJ, Kim K. A homochiral metal-organic porous material for enantioselective separation and catalysis. Nature. ;404(6781):982-986. 2000
    • Fenoglio I, Croce A, Di Renzo F, Tiozzo R, Fubini B. Pure-silica zeolites (Porosils) as model solids for the evaluation of the physicochemical features determining silica toxicity to macrophages. Chemical Research in Toxicology. ;13(6):489-500. 2000

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    Images

    imageNASA Image: ISS005E19042 - This is a view of the Zeolite Crystal Growth (ZCG) experiment as part of EXpediting the PRocess of Experiments to the Space Station (EXPRESS) Rack 2 located in the U.S. Laboratory. The image was taken by an Expedition Five crewmember.
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    imageNASA 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.
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    imageScanning Electron Microscopy image of flight (a) and Earth (b) control zeolite crystals.
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    Information Provided and Updated by the ISS Program Scientist's Office
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