Methods for removing anions from water
AssigneeChemtreat, Inc.
InventorsVladimir Djukanovic, Nicholas Seymour, William Henderson, Oleh Weres
Life of this patent
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Abstract
Methods are disclosed for treating water containing a target anion to remove the target anion. The methods can include preparing a treatment composition solution that contains a metal treatment agent, adjusting the treatment composition solution to a first pH that is alkaline and then to a second pH that is acidic, and contacting the treatment composition solution with the water that contains the target anion.
Claims21
A method of treating water that contains a target anion, the method comprising:
- providing a treatment composition solution containing a metal treatment agent;
- increasing the pH of the treatment composition solution with a pH adjusting agent to a first pH that is greater than 8.3, and then decreasing the pH of the treatment composition solution to a second pH that is less than 4.5;
- and
- contacting the treatment composition solution with the water that contains the target anion such that the target anion precipitates.
A method of treating water that contains selenate, the method comprising:
- providing a treatment composition solution containing a metal treatment agent;
- increasing the pH of the treatment composition solution with a pH adjusting agent to a first pH that is in a range of from 8.3 to 10, and then decreasing the pH of the treatment composition solution to a second pH that is in a range of from 2 to 6;
- and
- contacting the treatment composition solution with the water that contains selenate, and wherein the metal treatment agent reduces less than 5 wt. % of the selenate.
A method of treating water that contains a multivalent target anion, the method comprising:
- providing a treatment composition solution containing a metal treatment agent that is a soluble salt of a multivalent cation;
- increasing the pH of the treatment composition solution with a pH adjusting agent so that the pH is in the range of 8.3 to 10 and causing at least 80 wt. % of the metal treatment agent to precipitate, and then controlling the pH of the treatment composition solution so that the pH is acidic and so that the precipitated metal treatment agent becomes sufficiently positively charged that the treatment composition solution exhibits a positive measured colloidal surface charge as measured by a Mütek™ PCD-04 Particle Charge Detector, and so that at least 80 wt. % of the metal treatment agent is maintained as a precipitate;
- and
- contacting the treatment composition solution with the water that contains the multivalent target anion, and wherein the multivalent target anion adsorbs onto the positively charged precipitated metal treatment agent.
Dependencies are inferred from the claim text.