Gallium Enhances Water Purification | June 22, 2009 Issue - Vol. 87 Issue 25 | Chemical & Engineering News
Volume 87 Issue 25 | p. 35 | Concentrates
Issue Date: June 22, 2009

Gallium Enhances Water Purification

By substituting a single gallium atom into an aluminum cluster, researchers create an improved coagulating agent for water treatment
Department: Science & Technology
Keywords: polycation, water treatment, coagulant
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CLEANING UP
The gallium-based polycation GaAl12O4(OH)24(H2O)127+ outperformed aluminum-only and germanium analogs in lab tests to remove natural bacteriophages from Rio Grande River water (pfu = plaque-forming units).
Credit: Mona Aragon/Sandia
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CLEANING UP
The gallium-based polycation GaAl12O4(OH)24(H2O)127+ outperformed aluminum-only and germanium analogs in lab tests to remove natural bacteriophages from Rio Grande River water (pfu = plaque-forming units).
Credit: Mona Aragon/Sandia

By substituting a single gallium atom into an aluminum cluster coagulating agent, a research team led by Tom A. Stewart and May Nyman of Sandia National Laboratories has created an improved material for water purification (Environ. Sci. Technol., DOI: 10.1021/es803683t). Cationic coagulants such as ferric chloride, aluminum sulfate, or polyaluminum chloride (PACl) are used at the front end of water treatment processes to clarify water by neutralizing and trapping anionic natural organic matter, clay particles, and a host of microbes. PACl's major component is the polycationic cluster Al13O4(OH)24(H2O)127+, and as part of an effort to optimize the material, the researchers found that replacing the central aluminum atom with a gallium atom makes a big difference. One reason for the enhancement is that the gallium analog is less prone to deprotonation and maintains its charge better than the aluminum cluster. The gallium material also resists transforming into larger clusters, which is a problem that reduces PACl's shelf life. Nyman says the team has filed for a patent on the gallium-based cluster and is working with Kemira, a major producer of water treatment chemicals, to explore the commercial potential of the new coagulant.

 
Chemical & Engineering News
ISSN 0009-2347
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