High Capacity Oxoanion Chelating Media From Hyperbranched Macromolecules
A resin is provided for selectively binding to certain anions in aqueous solution. The beads are prepared by cross-linking macromolecules such as hyperbranched PEI, and functionalizing with groups containing vicinal diol moieties.
1 . An oxoanion-selective microparticle comprising a hyperbranched macromolecular structure (A) comprising a plurality of branches, a plurality of terminal functional groups, and a plurality of cross-linking moieties within the same molecular structure;
wherein each of said plurality of branches comprises an N-substituted or N,N-substituted n-aminoalkyl moiety (B) comprising one or two substituent moieties;
wherein each of said substituent moieties comprises one of the following:
(a) another of said plurality of branches;
(b) one of the plurality of terminal functional groups; or
(c) one of the cross-linking moieties attached at a first cross-linking end, wherein the cross-linking moiety further comprises a second cross-linking end, by which the moiety is also one of said substituent moieties of one of said plurality of branches at a different location within the hyperbranched macromolecular structure A;
wherein A has a molecular weight of at least 1500 grams per mole;
wherein A comprises essentially no primary amine moieties; and
wherein each of the plurality of terminal functional groups comprises a vicinal diol moiety.
2 . The microparticle of claim 1 , wherein the cross-linking moieties consist of a carbon backbone of at least three carbon atoms, each carbon atom optionally substituted with one or more functional groups.
3 . The microparticle of claim 2 , wherein the cross-linking moieties are selected from the group consisting of —CH 2 —CHOH—CH 2 — and —CH 2 —CH 2 —CH 2 —
4 . The microparticle of claim 1 , wherein the terminal functional groups are 2,3-dihydroxypropyl.
5 . The microparticle of claim 1 , wherein the terminal functional groups are (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoyl.
6 . The microparticle of claim 1 , wherein the terminal functional groups are (2R,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl.
7 . The microparticle of claim 1 , wherein the mean diameter of the microparticle is greater than about 400 μM.
8 . The microparticle of claim 1 , wherein the mean diameter of the microparticle is greater than about 50 μM.
9 . The microparticle of claim 1 , wherein the boron sorption capacity of the microparticle is greater than about 1.5 mMol/g in aqueous solution, when the equilibrium boron concentration of the microparticle is about 100 mM.
10 . A method for preparing an oxoanion-selective microparticle comprising:
(a) providing a branched polyethyleneimine molecule with a molecular weight of at least 1500 grams per mole;
(b) reacting the branched polyethyleneimine molecule with at least one cross-linking agent to produce a cross-linked resin matrix comprising a plurality of primary and/or secondary amine moieties; and
(c) after step (b), reacting the cross-linked resin matrix with a functionalization agent comprising a functional group —R, such that each of said primary and/or secondary amine moieties is substituted for the functional group —R, wherein —R is a structure comprising at least one vicinal diol moiety.
11 . The method of claim 10 , wherein each of the at least one the cross-linking agents contains a carbon chain with two ends, with a first linking functional group on the first end, and a second linking functional group on the second end, wherein the first and second linking functional groups are selected from the group consisting of acyl and epoxyethyl.
12 . The method of claim 11 , wherein each of the at least one cross-linking agents is selected from the group consisting of epichlorohydrin and 1-bromo-3-chloropropane.
13 . The method of claim 12 , wherein the cross-linking agents comprise both epichlorohydrin and 1-bromo-3-chloropropane.
14 . The method of claim 10 , wherein the functionalization agent is D-Glucono-1,5-lactone.
15 . The method of claim 10 , wherein the functionalization agent is oxiran-2-ylmethanol.
16 . The method of claim 15 , further comprising:
(d) after step (c), reacting the cross-linked resin matrix with 4-toluenesultonyl chloride;
(e) after step (d), reacting the cross-linked resin matrix with n-methyl glucamine.
17 . The method of claim 10 , wherein the functionalization agent is mannitol epoxide.
18 . An oxoanion-selective microparticle prepared by the method of claim 10 .
19 . A method for filtering oxoanions from an aqueous solution, comprising:
providing a solution containing a first quantity of an oxoanion selected from the group consisting of borate, germanate, arsenate (V), arsenate (III), vanadate, molybdate, and tungstate;
providing a stationary bed comprising the microparticles of claim 1 , having voids between said microparticles to allow the passage of an aqueous solution;
passing said solution through said stationary bed; and
recovering said solution after it passes through said stationary bed.
20 . The method of claim 19 , further comprising:
passing an acid solution through said stationary bed to leach the oxoanion from the microparticles; and
passing a basic solution through said stationary bed to regenerate the microparticles.