Abstract:The by-product thenardite (sodium sulfate), generated during wet flue gas desulfurization,poses significant environmental and land-use challenges due to its inherent chemical properties and lowresource recovery efficiency. This study addresses this issue by developing a novel approach thatleverages modified ion exchange membranes in the electrodialysis process to optimize the separationefficiency of sulfate and sodium ions, facilitating the resource utilization of thenardite. Cation exchangemembranes were enhanced through modification with pyrrole and tetraethyl orthosilicate to improvetheir mechanical strength and sodium ion migration. Anion exchange membranes were treated withpolyethyleneimine and dopamine to optimize their surface structure and increase selective permeabilityfor sulfate ions. Characterization techniques, including Fourier transform infrared spectroscopy (FTIR)and scanning electron microscopy (SEM), revealed that the modified membranes exhibited asignificantly enhanced surface negative charge, a more uniform pore distribution, and improvedstructural compactness. Contact angle measurements indicated that these modifications increasedmembrane hydrophilicity, thereby increasing ion migration efficiency. Experimental resultsdemonstrated that sodium ion permeability increased by 0.36% for pyrrole-modified cation exchangemembranes compared to unmodified membranes, while dopamine-modified anion exchange membranesachieved a 12.57% improvement in sulfate ion permeability. Further electrodialysis experimentsshowed that, under an applied voltage of 50 V at room temperature, the combination of modifiedmembranes enabled efficient separation of sulfate and sodium ions, achieving a purity of 99%. Notably,after six testing cycles, the modified membranes exhibited excellent stability in ion selectivity andmigration efficiency, meeting the requirements for long-term industrial operation. This studyinnovatively integrates multiple modification strategies to optimize ion exchange membranes,significantly enhancing the separation efficiency and operational stability of the electrodialysis processfor thenardite resource utilization. The findings provide crucial technical support for the green resourcerecovery of thenardite and offer a reference for the treatment of complex industrial wastewater. Close-