Preparation method of modified organic film for extracting lithium from seawater

The invention provides a preparation method of a modified organic film for extracting lithium from seawater. The preparation method comprises the following steps: carrying out grafting on an aldehydegroup modified polymer as a raw material and benzo 15-crown-5 to form a crown ether modified polymer film; carrying out acid washing and water washing on a lithium titanate powder-loaded carbon-basedmaterial to remove lithium ions; loading the carbon-based material on a porous organic film; and grafting the aldehyde group of the organic film with the amino group of the crown ether to obtain the modified organic film for seawater lithium extraction. According to the invention, an inorganic adsorbent is loaded on the surface layer of an organic film to improve the lithium ion concentration around the organic adsorbent, so that the organic phase is purified relative to an adsorption source of lithium ions, the content of adsorbed lithium ions in the organic phase is increased, the defects that an organic adsorbent is