Method and device for separating monovalent ions and multivalent ions in water

The invention discloses a method and device for separating monovalent ions and multivalent ions in water, and the method comprises the following steps: S1, introducing water to be treated into a container with an electrodialysis membrane for electrodialysis, and separating the water to be treated into fresh water and first concentrated water by the electrodialysis membrane; S2, carrying out nanofiltration on the fresh water to generate produced water and second concentrated water; and S3, carrying out reverse osmosis concentration on the produced water to form third concentrated water, and carrying out electrodialysis on the third concentrated water, or directly carrying out electrodialysis on the produced water to form second produced water and first concentrated water. The device comprise a fresh water chamber and a concentrated water chamber, wherein the fresh water chamber and the concentrated water chamber are separated by the electrodialysis membrane; the electrodialysis membrane comprises at least one