Chalcogel

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A chalcogel or properly metal chalcogenide aerogel is an aerogel made from chalcogenides. [1] Chalcogels preferentially absorb heavy metals, [2] such as mercury, lead, and cadmium, from water. [3] Sulfide chalcogels are also very good at desulfurization. [4]

Metal chalcogenide aerogels can be prepared from thiolysis [5] or nanoparticle condensation [6] [7] and contain crystalline nanoparticles in the structure. [7] The synthetic method can be extended to many thioanions, including tetrathiomolybdate-based chalcogels. [8] Different metal ions have been used as linkers Co2+, Ni2+, Pb2+, Cd2+, Bi3+, Cr3+. [8] [9] [10]

When the gels are dried aerogels with high surface areas are obtained and the materials have multifunctional nature. For example, chalcogels are especially promising for gas separation. They were reported to exhibit high selectivity in CO2 and C2H6 over H2 and CH4 adsorption. [8] [10] The latter is relevant to exit gas stream composition of water gas shift reaction and steam reforming reactions (reactions widely used for H2 production). For example, separation of gas pairs such as CO2/H2, CO2/CH4, and CO2/N2 are key steps in precombustion capture of CO2, natural gas sweetening and postcombustion capture of CO2 processes leading ultimately at upgrading of the raw gas. The above mentioned conditioning makes the gas suitable for a number of applications in fuel cells.

Chalcogels were shown to be very effective at capturing radionuclides from nuclear waste such as 99Tc, and 238U, and especially 129I. [11]

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References

  1. ↑ Biello, David (2007-07-26). "Heavy Metal Filter Made Largely from Air". Scientific American. Archived from the original on 2007-09-26. Retrieved 2007-07-27.
  2. ↑ Bag, S.; Trikalitis, P. N.; Chupas, P. J.; Armatas, G. S.; Kanatzidis, M. G. (2007). "Porous Semiconducting Gels and Aerogels from Chalcogenide Clusters". Science. 317 (5837): 490–493. Bibcode:2007Sci...317..490B. doi: 10.1126/science.1142535 . PMID   17656718.
  3. ↑ Carmichael, Mary. First Prize for Weird: A bizarre substance, like 'frozen smoke,' may clean up rivers, run cell phones and power spaceships. Newsweek International, 2007-08-13. Retrieved on 2007-08-05.
  4. ↑ "New Sponge-like Material Can Remove Mercury From Water, Separate Hydrogen From Other Gases And Pull Sulfur Out Of Crude Oil". ScienceDaily. 2009-05-17.
  5. ↑ Stanić, Vesna; Pierre, Alain C.; Etsell, Thomas H.; Mikula, Randy J. (1996). "Preparation and characterization of Ge2". Journal of Materials Research. 11 (2): 363–372. Bibcode:1996JMatR..11..363S. doi:10.1557/JMR.1996.0044.
  6. ↑ Gacoin, Thierry; Malier, Laurent; Boilot, Jean-Pierre (1997). "New Transparent Chalcogenide Materials Using a Sol−Gel Process". Chem. Mater. 9 (7): 1502–1504. doi:10.1021/cm970103p.
  7. 1 2 Yao, Q.; Brock, S.L. (2010). "Optical sensing of triethylamine using CdSe aerogels". Nanotechnology. 21 (11): 115502. Bibcode:2010Nanot..21k5502Y. doi:10.1088/0957-4484/21/11/115502. PMID   20173226. S2CID   22430096.
  8. 1 2 3 Polychronopoulou, Kyriaki; Malliakas, Christos D.; He, Jiaqing; Kanatzidis, Mercouri G. (2012). "Selective Surfaces: Quaternary Co(Ni)MoS-Based Chalcogels with Divalent Selective Surfaces: Quaternary Co(Ni)MoS-Based Chalcogels with Divalent (Pb2+, Cd2+, Pd2+) and Trivalent (Cr3+, Bi3+) Metals for Gas Separation". Chemistry of Materials. 24 (17): 3380–3392. doi:10.1021/cm301444p.
  9. ↑ Bag, S.; Gaudette, A.F.; Bussell, M.E; Kanatzidis, M.G (2009). "Spongy chalcogels of non-platinum metals act as effective hydrodesulfurization catalysts". Nat. Chem. 1 (3): 217–24. Bibcode:2009NatCh...1..217B. doi:10.1038/nchem.208. PMID   21378851.
  10. 1 2 Oh, Youngtak; Bag, Santanu; Malliakas, Christos D.; Kanatzidis, Mercouri G. (2011). "Selective Surfaces: High-Surface-Area Zinc Tin Sulfide Chalcogels". Chem. Mater. 23 (9): 2447–2456. doi:10.1021/cm2003462.
  11. ↑ Riley, Brian J.; Chun, Jaehun; Um, Wooyong; Lepry, William C.; Matyas, Josef; Olszta, Matthew J.; Li, Xiaohong; Polychronopoulou, Kyriaki; Kanatzidis, Mercouri G. (2013). "Chalcogen-Based Aerogels As Sorbents for Radionuclide Remediation". Environ. Sci. Technol. 47 (13): 7540–7. Bibcode:2013EnST...47.7540R. doi:10.1021/es400595z. PMID   23763706.
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