Electrospinning of porous PS-MOF composite nanofibers for VOCs adsorption: Effects of porous structure on equilibrium and dynamic adsorption

Electrospun nanofibers are promising adsorbents for volatile organic compounds (VOCs); however, their typically non-porous structure limits access to active adsorption sites and constrains performance. In this study, porous polystyrene (PS)–HKUST-1 composite nanofibers were fabricated to enhance VOC adsorption from air streams. Hierarchical micro- and mesoporosity was introduced into the nanofibers, improving the utilization of the embedded metal–organic frameworks (MOFs). Methyl ethyl ketone (MEK) and cyclohexane were investigated separately as representative VOCs under equilibrium and dynamic adsorption conditions. Among the investigated compositions, the porous 16.6% PS–83.4% HKUST-1 nanofiber exhibited the best equilibrium adsorption performance. In dynamic adsorption experiments at an inlet concentration of 100 ppm, the porous nanofiber exhibited higher adsorption capacity for MEK (210.5 mg g −1 ) compared to cyclohexane (116.0 mg g −1 ), with a longer 5% breakthrough time (t₅%). Increasing the inlet concentration to 200 ppm resulted in higher adsorption capacities for both compounds compared to 100 ppm, reaching 289.9 mg g −1 for MEK and 175.0 mg g −1 for cyclohexane, while breakthrough occurred earlier for both. Compared with non-porous nanofibers of identical HKUST-1 loading, the porous nanofibers consistently exhibited superior equilibrium and dynamic adsorption performance. Cyclic adsorption–desorption tests over five cycles showed a gradual decline in capacity, indicating partial adsorbate retention and promising reusability. These results demonstrate that introducing hierarchical porosity into electrospun PS–HKUST-1 nanofibers is an effective strategy for enhancing VOC adsorption and air purification applications. • Hierarchically porous PS–HKUST-1 nanofibers were successfully fabricated. • Porosity enhanced VOC adsorption under equilibrium and dynamic conditions. • Optimal PS–HKUST-1 nanofibers exhibited higher adsorption capacity and extended breakthrough times. • Porous nanofibers outperformed non-porous counterparts at identical MOF loading. • High adsorption capacity was retained after five adsorption–desorption cycles.