Water purification

A method for treating a first aqueous solution to remove at least one anion from the first aqueous solution, comprising:

• (a) mixing the first aqueous solution with a first water-immiscible extractant phase in a first apparatus to form a first unstable emulsion, wherein the extractant phase comprises an extractant comprising a cationic molecule and an anionic base, wherein the extractant forms an ion pair with the at least one anion from the first aqueous solution;
• (b) separating the first unstable emulsion into a first treated aqueous phase and a first loaded extractant phase, the ion pair being present in the first loaded extractant phase;
• (c) mixing the first loaded extractant phase with an aqueous stripping solution containing an alkali metal cation and an anionic base to produce a second unstable emulsion;
• and
• (d) separating the second unstable emulsion into (i) a regenerated extractant phase stripped of the at least one anion separated from the first aqueous solution and containing the anionic base of the aqueous stripping solution, and (ii) a second aqueous phase containing a salt formed from the alkali metal cation and the at least one anion separated from the first aqueous solution.

A method for treating a first aqueous solution to remove at least one anion from the first aqueous solution, comprising:

• (a) mixing the first aqueous solution with a first water-immiscible extractant phase in a first apparatus to form a first unstable emulsion, wherein the extractant phase comprises an extractant comprising a cationic molecule and an anionic base, wherein the extractant forms an ion pair with the at least one anion from the first aqueous solution;
• (b) separating the first unstable emulsion into a first treated aqueous phase and a first loaded extractant phase, the ion pair being present in the first loaded extractant phase;
• (c) mixing the first loaded extractant phase with an aqueous stripping solution containing an alkali metal cation and an anionic base to produce a second unstable emulsion;
• (d) separating the second unstable emulsion into (i) a regenerated extractant phase stripped of the at least one anion separated from the first aqueous solution and containing the anionic base of the aqueous stripping solution, and (ii) a second aqueous phase containing a salt formed from the alkali metal cation and the at least one anion separated from the first aqueous solution;
• (e) treating the second aqueous phase by one or more of an oil/water separator, a solid/liquid separator, and an organic odor sorbent;
• and
• (f) purifying and collecting the salt formed from the alkali metal cation and the at least one anion.