Diffusion　dialysis　employing　anion　exchange　membranes　(AEMs)　as　an　energy-efficient　and　environmentally-friendly　technology　is　highly　desirable　for　acid　recovery　from　acidic　wastewater.　Herein,　porous　AEMs　with　high　acid　permeability　were　tailored　via　a　simple　one-step　route,　in　which　porous　chloromethyl　polyethersulfone　(CMPES)　membrane　substrate　was　modified　by　1,4-dimethylpiperazine　(DMP)　to　achieve　simultaneous　crosslinking　and　quaternization.　The　prepared　piperazine-functionalized　AEMs　were　characterized　by　morphology,　ion　exchange　capacity,　water　uptake,　water　contact　angle,　stabilities　and　diffusion　dialysis　performance.　Specifically,　the　optimal　AEM　(i.e.,　DPES-3h)　applied　in　acid　recovery　from　the　simulated　HCl　(1.0　mol　L−1)/FeCl2　(0.2　mol　L−1)　mixed　solution　at　25　°C　possessed　a　proton　dialysis　coefficient　(UH+)　of　43.2　×　10−3　m　h−1　and　an　acid/salt　separation　factor　(S)　of　29.6,　remarkably　outperforming　the　previously　reported　state-of-the-art　AEMs.　Furthermore,　the　DPES-3h　AEM　showed　excellent　thermal　stability　and　acid　resistance,　suggesting　considerable　durability　for　long-term　application.　These　results　indicated　that　our　piperazine-functionalized　porous　AEMs　appear　to　be　promising　for　acid　recovery　from　the　acidic　waste　streams　via　diffusion　dialysis.　©　2022