In　the　sustainability　concept　framework,　wastewater　highly　loaded　with　acid　is　considered　as　a　valuable　resource,　rather　than　a　waste.　Diffusion　dialysis　employing　anion　exchange　membranes　is　a　feasible　solution　to　extracting　acid　from　this　waste　stream.　However,　conventional　anion　exchange　membranes　have　dense　spatial　structures　with　no　observable　pores　even　at　nanoscale,　which　limits　the　transfer　of　protons.　Porous　anion　exchange　membranes　provide　a　practical　avenue　to　enhance　the　proton　transfer　due　to　their　unique　spatial　structure.　In　this　study,　novel　porous　anion　exchange　membranes　were　designed　by　one-step　crosslinking　and　quaternization　of　porous　brominated　poly　(phenylene　oxide)　membrane　substrate　by　1,　4-diazabicyclo　[2.2.2]　octane.　The　resultant　porous　anion　exchange　membranes　showed　a　high　performance　in　acid　recovery　by　diffusion　dialysis,　due　to　their　uniquely　tailored　microstructures　including　an　extremely　thin　selective　layer　and　high　free　space　volume.　Specifically,　the　optimal　anion　exchange　membrane　possessed　an　acid　dialysis　coefficient　of　0.066　±　0.003　m　h−1　and　an　acid/salt　separation　factor　of　96.9　±　2.5　in　the　HCl/FeCl2　mixture　solution,　outperforming　the　commercial　anion　exchange　membrane　(i.e.,　DF-120,　acid　dialysis　coefficient　of　0.0085　m　h−1　and　acid/salt　separation　factor　of　18.5).　This　study　demonstrates　the　great　potential　in　constructing　advanced　anion　exchange　membranes　at　large　scale　for　efficient　acid　recovery　from　highly　acidic　wastewater　to　support　environment　sustainability.　©　2021　Elsevier　B.V.