Heavy-metal-ion capture, ion-exchange, and exceptional acid stability of the open-framework chalcogenide (NH4)4in 12Se20

Manolis J. Manos, Christos D. Malliakas, Mercouri G. Kanatzidis

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

The hydrothermal synthesis of the purely inorganic open-frame-work indium selenide (NH4)4In12Se20 (1) is reported. Compound 1 exhibits a unique three-dimensional open-framework structure. The framework of 1 shows an unusual, for a chalcogenide compound, rigidity arising from the unprecedented connection mode of its building blocks. Compound 1 possesses ion exchange capacity for Cs+, Rb+, NH4+, but it has selectivity against Na+ and Li+. It also showed exceptional stability in relatively concentrated hydrochloric acid. Ion exchange of 1 with hydrochloric water solutions can produce its solid acid analogue H2-(NH4) 2In12Se20. The maximum cation-exchange capacity of 1 was found equal to two equivalents per mol, which is consistent with an exchange mechanism taking place in the 1D-channels formed by the largest cavities. In addition, 1 can do ion-exchange with heavy-metal ions like Hg 2+, Pb2+, and Ag+. The capacity of 1 to clean water solutions from heavy-metal ions was preliminarily investigated and found very high. Specifically, 1 can remove 99.9% of Hg2+, 99.8% of Ag +, and 94.9% of Pb2+ from aqueous solutions of each of these ions. Using different synthetic conditions, we isolated compound (NH 4)2In12Se19 (2), which also has as good an acid stability as 1, but no ion-exchange properties. Overall, this work provides new hydrothermal synthetic approaches for isolation of all-inorganic open-framework chalcogenides.

Original languageEnglish
Pages (from-to)51-58
Number of pages8
JournalChemistry - A European Journal
Volume13
Issue number1
DOIs
Publication statusPublished - Jan 8 2007

Keywords

  • Chalcogens
  • Indium
  • Ion exchange
  • Selenium
  • Solid acid

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

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