Composite having ion exchange function and preparation method and use thereof

A method for preparing a composite material, wherein the method comprises the following steps:

• adding Lewis acid and/or strong protonic acid as a catalyst into the composite material during compounding, wherein the protonic acid is selected from H2SO4, CF3SO3H or H3PO4;
• the Lewis acid is selected from ZnCl2, FeCl3, AlCl3, organotin, organic antimony or organic tellurium;
• and
• reacting nitrile groups of at least one nitrile group-containing ion exchange resin with nitrile groups of functional monomers grafted on a porous fluoropolymer membrane to form a triazine ring crosslinked structure,
• wherein the composite material comprises one or more ion exchange resins having an ion exchange function and a porous fluoropolymer membrane, said one or more ion exchange resins having an ion exchange function is/are filled in micropores of said porous fluoropolymer membrane and covered on surfaces of said porous fluoropolymer membrane;
• the pore surfaces of said porous fluoropolymer membrane are modified by nitrile group-containing functional monomers through grafting;
• at least one of the ion exchange resins forming the composite material comprises nitrile groups, and the nitrile groups and that of the functional monomers grafted on the porous fluoropolymer membrane form a triazine ring crosslinked structure.