Manganese oxide-based and metallomanganese oxide-based ion-exchangers for removing mercury (+2) ions from liquid streams

摘要

A process for removing Hg2+ ions from a liquid stream is disclosed. The process involves contacting the liquid stream with specified ion-exchangers based on manganese oxides and metallomanganese oxides of the form
An+wM3+xMn1-xO2
where A can be cations such as Na+ or Mg2+, M3+ can be metals such as Fe3+ or Co3+, and the TIC, the theoretical ion exchange capacity per framework metal atom, varies from 0.08 to 0.25. These ion-exchangers are particularly effective in removing Hg2+ ions from aqueous streams even in the presence of Mg2+ and Ca2+ ions.

主权项

1. A process for removing an Hg2+ contaminant from a liquid stream comprising contacting the liquid stream with a manganese-oxide-based ion-exchanger or a metallomanganese oxide-based ion-exchanger for a time sufficient to adsorb the Hg2+ contaminant onto the ion-exchanger, wherein an as-synthesized manganese oxide-based ion-exchanger and an as-synthesized metallomanganese oxide-based ion-exchanger may be described by the general formulation on an anhydrous basis
An+wM3+xMn1-xO2 where “A” is at least one exchangeable cation selected from the group of H+, Na+, Li+, NH4+, Mg2+ and Ca2+, “n” is the weighted average valence of the “A” cations and ranges from 1 to 2, “w” is the mole ratio of “A” to framework metals (Mn+M) and varies from 0.04 to 0.25, “n*w” is the framework charge balanced by the “A” cations per framework metal and varies from 0.08 to 0.25, “M” is at least one metal of +3 valence selected from the group Al, Fe, Co, Cr, and Ga, “x” is the mole fraction of M that substitutes for Mn and varies from 0 to 0.20.