Membrane　separation　is　an　important　separation　and　purification　technology,　membrane　materials　are　the　key　to　membrane　separation　technology,　and　the　rapid　development　of　two-dimensional　materials　in　recent　years　has　brought　new　opportunities　for　membrane　separation　technology.　Graphene　oxide　(GO)　is　a　hydrophilic　two-dimensional　material,　and　its　unique　physical　and　chemical　structure　and　properties　give　it　the　potential　to　become　a　high-performance　separation　membrane;　however,　the　instability　limits　its　application.　In　this　study,　a　two-dimensional　material,　graphite-phase　carbon　nitride　(g-C3N4),　was　integrated　into　graphene　oxide　(GO)　to　address　the　challenges　associated　with　its　practical　applications.　This　modification　not　only　endows　the　material　with　more　advantageous　properties　as　a　membrane　but　also　introduces　a　heterogeneous　structure　that　bolsters　the　composite　membrane’s　stability.　This　structure　also　enhances　the　permeability　and　selectivity　of　the　membrane,　leading　to　impressive　results　in　self-driven　permeation　tests　and　staggered-flow　filtration　tests　under　applied　pressure.　Following　additional　surface　charge　modifications,　the　composite　membrane　demonstrated　a　separation　efficiency　of　approximately　90.4%　in　permeation　tests　and　an　impressive　separation　efficiency　of　63.8%　in　filtration　tests　for　binary　mixed　salt　solutions.　These　results　indicate　a　significant　capability　for　mono-　and　divalent　ion　separation,　suggesting　promising　potential　for　salt　separation　applications.　©　2025　The　Authors.　Published　by　American　Chemical　Society.