Electrospun fibrous mats as a skeleton for fabricating hierarchically structured materials as sorbents for Cu²⁺

Based on the combination of the electrospinning and evaporation-induced self-assembly mesopore-forming technique, a facile strategy is developed to fabricate self-standing thiol-functionalized membranes with hierarchical structures (Macro-Mesopores and binding sites). This membrane is prepared using electrospun polystyrene (PS) fibers as the skeleton and non-ionic surfactant F127 as the structure-directing agent with co-condensation of tetraethyl orthosilicate (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS). The prepared membranes were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), nitrogen sorption, mercury intrusion porosimetry, and Fourier transform infrared (FT-IR) spectra. The macropore constructed by the electrospun PS membrane ranged from 1 to 10 μm, while the highly ordered mesopore formed by F127 was around 5 nm and heavy metals binding cites of thiol groups were also presented, respectively. Using Cu²⁺ ions as the model bivalent cation, an excellent removal capacity of the prepared membrane was confirmed by the static sorption and dynamic filtration experiments with a high flux up to 1.30 × 10⁴ L h⁻¹ m⁻² bar⁻¹. We find that regeneration of the membranes and the metal ion recovery can be facially realized by the treatment using acid solution. These results demonstrate that the developed strategy has significant potential for the design and fabrication of high-performance membranes with hierarchical structures and could find impactful application in the field of industrial catalysis, separation, and environmental pollution control and resources reuse.