Method for extracting lithium from solution containing lithium

A method for extraction of lithium from a solution including lithium, comprising:

• separating a solution including lithium into a monovalent ion-containing solution and a solution including ions having divalence or more using a separation membrane having a negative charge on its surface;
• removing impurities from the monovalent ion-containing solution;
• and
• adding a phosphorus supplying material to the monovalent ion-containing solution where impurities are removed and then precipitating dissolved lithium into lithium phosphate,
• wherein the separation membrane comprises a coating having a sulfone group that is coated onto a polyamide substrate, wherein the sulfone group provides the negative charge.