Ion exchange resins selective for the complexation of univalent anions in aqueous solutions
Ion exchange resin macroporous beads for the highly selective extraction of univalent anions from aqueous solutions. A specific example is the removal of dicyanoaurate and dicyanoargentate from cyanide leach solutions and tailings. The beads have a maximum number of ligands specific for the desired univalent anion, while maintaining sufficient separation to minimize binding of polyvalent ions. The beads are prepared using a functionalized monomer with the use of a specifically tuned coordinator. The beads can be used as a sensor for detecting the amount of anions captured when interrogated by an appropriate light source.
1. A macroporous ion exchange resin polymer bead comprising:
a plurality of cationic ligands selective for a specific univalent ion, the ligands co-polymerized with a non-complexing monomer and a crosslinker;
wherein the bead does not comprise the univalent ion;
wherein each ligand comprises a coordination site supplying the appropriate charge for the univalent ion; and
wherein the ligands are sufficiently separated to minimize binding of polyvalent ions to the bead.
2. The bead of claim 1 wherein the monomer comprises styrene and the crosslinker comprises divinyl benzene.
3. The bead of claim 1 wherein the ligand is monodentate.
4. The bead of claim 1 comprising a number of ligands to substantially maximize a binding capacity of the bead to the univalent ion while maintaining spatial separation to minimize cooperative effects between ligands.
5. The bead of claim 1 wherein the ligand is selected from the group consisting of cationic oxygen containing heterocyclics, cationic nitrogen containing heterocyclics, cationic sulfur containing heterocyclics, cationic phosphorous containing heterocyclics, ammonium salts, phosphonium salts, acylinium salts, metallocenium salts, amidinium salts, imminium salts, trityl salts, 4-vinylbenzyl-N,N,N-tripentylammonium, 4-vinylbenzyl-N,N-dimethyl-N-hexylammonium, N,N-dimethyl N-heptylammonium, and 4-vinylbenzyl-N,N-dimethyl-N-decylammonium.
6. The bead of claim 1 wherein the univalent ion is selected from the group consisting of monatomic univalent anions, polyatomic univalent anions, halides, fluoride, chloride, bromide, iodide, univalent oxyanions, perbromate, periodate, permanganate, pertechnetate, nitrite, nitrate, perchlorate, cyanide, cyanate, thiocyanate, organic anions, benzoate, acetate, precious metal cyanide complexes, dicyanoaurate, and dicyanoargentate.
7. The bead of claim 1 wherein the plurality of ligands are specific for a luminescent univalent ion is luminescent.
8. A method for extracting univalent ions from a liquid, the method comprising:
flowing the liquid past a plurality of the beads of claim 1 ;
maintaining contact between the liquid and the beads sufficiently long for the liquid to substantially penetrate the beads; and
binding the univalent ions to the ligands.
9. The method of claim 8 wherein the plurality of beads is in the form of a bed or column.
10. The method of claim 8 wherein the liquid comprises an aqueous solution, potable water, produced water, mine effluent, mine waste, industrial effluent, a settling pond, an evaporation pond, a contaminated natural body of water, or an underground water table.
11. The method of claim 8 further comprising:
shining light on the beads;
luminescing the univalent ions bound to the beads; and
measuring a characteristic of the luminescence.
12. The method of claim 11 wherein the characteristic is intensity or wavelength.
13. The method of claim 11 further comprising determining when the plurality of beads is saturated with bound univalent ions.
14. The method of claim 8 wherein the plurality of beads have an average size between approximately 50 microns and approximately 1.5 mm.
15. The method of claim 14 wherein the plurality of beads have an average size between approximately 300 microns and approximately 1000 microns.