Multifunctional ZIF-8/PS nanofiber membranes with hierarchical porous structure for simultaneous SO₂ capture and PM removal

The simultaneous removal of particulate matter (PM) and toxic gases (SO 2 , NO x , VOC S , etc.) remains a critical challenge in air pollution control. To address this, we developed a multifunctional zeolitic imidazolate framework-8 (ZIF-8)/polystyrene (PS) nanofiber membrane (ZIF-8/PS NFM), forming a hierarchical porous (micro-/ meso -/macroporous) structure for efficient PM capture and SO 2 adsorption. As a representative metal-organic framework, ZIF-8 offers exceptional gas adsorption capability due to its high specific surface area and uniform micropores. The incorporation of ZIF-8 nanoparticles into PS nanofibers enhanced the BET surface area (51 to 175 m 2 ·g −1 ), porosity (0.148 to 0.190 m 2 ·g −1 ), and tensile strength (0.24 to 1.45 MPa). In PM filtration tests, the optimized ZIF-8/PS NFM achieved outstanding removal efficiencies of 99.73 % (PM 0.3 ) and 99.96 % (PM 2.5 ), while maintaining low pressure drop (83 Pa and 27 Pa, respectively). Moreover, the membrane demonstrated a remarkable SO 2 adsorption capacity of 1370 mg·g −1 at 55 % relative humidity, attributed to its high surface area and abundant unsaturated Z n 2+ sites. This work provides a promising strategy for the synergistic capture of PM and SO 2 with high efficiency and stability.