Process for removing contaminant metal ions from liquid streams using metallo germanate molecular sieves
AssigneeUop LLC
InventorsRobert L. Bedard, Lisa M. King, John D. Sherman
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Abstract
This invention relates to a process for removing contaminant metal ions from a liquid stream. The process involves contacting the liquid stream with a crystalline molecular sieve having the pharmacosiderite structure and having germanium and M metals as framework elements. Optionally, titanium and silicon can also be framework elements. The M metals can be any metal which has octahedral coordination and has a valence of +2, +3, +4 or +5. Illustrative of these M metals are niobium, tin, antimony, aluminum, gallium and tantalum. These molecular sieves are particularly effective in removing cesium and strontium ions from aqueous streams.
Claims10
A process for removing a metal ion contaminant from a liquid stream comprising contacting the stream with a molecular sieve for a time sufficient to adsorb the metal ion contaminant onto the molecular sieve, the molecular sieve characterized in that it has the crystal structure of pharmacosiderite and has a chemical composition represented by an empirical formula of:
- A.sub.[(4+4y(4-m))/n] (Ge.sub.1-x M.sub.y.sup.+m Ti.sub.z.sup.+4).sub.4 (Ge.sub.1-p Si.sub.p).sub.3 O.sub.16
- where A is an exchangeable cation having a valence of +n and selected from the group consisting of alkali metals, alkaline earth metals, hydronium ion, ammonium ion, and mixtures thereof, M is at least one metal which has octahedral coordination and has a valence m of +2, +3, +4, or +5, x has a value from about 0.01 to about 1.0, y has a value from 0 to about 1.0, x=y+z, z has a value of zero to about 1.0 and p has a value from 0 to about 0.99, and when z is zero, M is selected from the group consisting of Nb.sup.+5, Ta.sup.+5, Sb.sup.+5, or Sn.sup.+4.
Dependencies are inferred from the claim text.