PURIFICATION OF ULTRA-HIGH SALINE AND CONTAMINATED WATER BY MULTI-STAGE ION CONCENTRATION POLARIZATION (ICP) DESALINATION

• US 20160115045A1
• Filed: 10/23/2015
• Published: 04/28/2016
• Est. Priority Date: 10/23/2014
• Status: Active Application

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Han, Jongyoon, Kim, Bumjoo, Kwak, Rhokyun
• Granted Patent: US 10,252,924 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 61/42 Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
• CPC Class Codes: C02F 1/4604 for desalination of seawater or brackish water
• CPC Class Codes: C02F 1/469 by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
• CPC Class Codes: C02F 1/4695 electrodeionisation
• CPC Class Codes: C02F 1/4698 electro-osmosis
• CPC Class Codes: C02F 2101/10 Inorganic compounds
• CPC Class Codes: C02F 2101/30 Organic compounds
• CPC Class Codes: C02F 2101/32 Hydrocarbons, e.g. oil
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: C02F 2201/46115 Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2301/04 Flow arrangements
• CPC Class Codes: C02F 2301/08 Multistage treatments, e.g. repetition of the same process step under different conditions

Abstract

A water stream is passed between two juxtaposed similar ion exchange membranes (AEMs or CEMs), forming an ion depletion and ion enrichment zones when an electric field is applied. As cations are selectively transferred through the CEMs, for example, anions are relocated in order to achieve electro-neutrality, resulting in the concentration drop (increase) in ion depletion (enrichment) zone. Trifurcation of the output channel allows collection of concentrated, dilute and intermediate streams, with the intermediate stream serving as input to the next stage of a serialized implementation.

Claims

1. A method of purifying and/or concentrating a first water stream containing ionic impurities comprising the steps:

a. directing the water stream in a channel comprising an inlet and an outlet and defined, at least in part by at least a first ion exchange membrane and at least a second ion exchange membrane, wherein the ion exchange membranes are juxtaposed and characterized by the same charge;

b. applying an electric field across the channel causing formation of an ion depletion zone comprising a purified water stream, formation of an ion enrichment zone comprising a concentrated ion aqueous stream and formation of a neutral concentration zone comprising an intermediate stream;

c. trifurcating the channel in relation to the ion depletion zone, the ion enrichment zone and the neutral concentration zone of step b to cause separation of the purified water stream, the intermediate stream and the concentrated ion aqueous stream;

d. collecting any portion of the purified water stream and/or the intermediate stream and/or the concentrated ion aqueous stream; and

wherein the concentration of ionic impurities in the collected intermediate stream is less than that found in the collected purified water stream and greater than that found in the collected concentrated ion aqueous stream, and the concentration of ionic impurities in the collected intermediate stream is substantially the same as the first water stream.

2. The method of claim 1, wherein the at least a first and at least a second juxtaposed ion exchange membranes are cationic exchange membranes.

3. The method of claim 1, wherein the at least a first and at least a second juxtaposed ion exchange membranes are anionic exchange membranes.

4. The method of claim 1, wherein the trifurcation of step c comprises at least one nonionic porous membrane.

5. The method of claim 4, wherein the at least one nonionic porous membrane is located at the outlet of the channel.

6. The method of claim 1, wherein the electric field is created by an electrode and a ground each located external and parallel to the channel.

7. The method of claim 6, wherein the electrode forms a second channel with the at least a first ion exchange membranes and the ground forms a third channel with the at least a second ion exchange membranes.

8. The method of claim 7, wherein the second and third channel are filled with an electrolyte solution.

9. The method of claim 8, wherein the electrolyte solution is the first water stream.

10. The method of claim 1 wherein the first water stream comprises salt.

11. The method of claim 1 wherein the first water stream comprises biomolecules.

12. The method of claim 1, wherein steps a through d are repeated and wherein the intermediate stream collected in step d acts as the first water stream in subsequent repetitions of the method.

13. The method of claim 12, wherein the electrical field of step b is common to at least one repetition of the method.