Cyclodextrin Composite Nanofiber Membrane: Impact of the Crosslinker Type on Steroid Hormone Micropollutant Removal from Water

β-Cyclodextrin (βCD) fibers electrospun on polymer supports have emerged as a promising composite with high performance water treatment. Here, alternative crosslinkers to incorporate βCD into electrospun polymeric nanofibers for the removal of steroid hormone micropollutants have been investigated. Composite nanofiber membranes (CNMs) were obtained based on polyethersulfone (PES) and crosslinked βCD nanofibers deposited on a PES ultrafiltration membrane support layer. The crosslinkers investigated are epichlorohydrin (EP), trimethylolpropane triglycidyl ether (TPTE), and triphenylolmethane triglycidyl ether (TMTE). The structure, morphology, and stability of as-prepared CNMs were characterized using FE-SEM and TGA analysis, while micropollutant removal was investigated in static adsorption and membrane filtration. All crosslinkers achieved the successful incorporation of βCD into the nanofiber as evidenced by TGA analysis before and after filtration. The βCD CNM using the crosslinker TPTE exhibited a significantly higher estradiol (E2) removal of about 95% within 5 h in static adsorption, while about the same removal (up to 93%) was achieved in filtration. E2 removal was independent of feed concentration (10 ng/L–100 μg/L) in static adsorption, while the removal decreased with concentration in filtration. The observed enhancement of hormone removal with the crosslinker type could not be attributed to the difference in crosslinking sites alone. The interactions between E2 and crosslinkers contributed to E2 removal in addition to the complexation between βCD and steroid hormones. The incorporation of βCD with three different crosslinkers in the CNM provides crosslinking options that all result in enhanced E2 removal at comparatively high water permeability.