Hierarchical CuO-ZnO/SiO₂ Fibrous Membranes for Efficient Removal of Congo Red and 4-Nitrophenol from Water

Hierarchical CuO-ZnO/SiO₂ (CZS) nanofibrous membranes are designed and fabricated to remove Congo red and 4-nitrophenol two common small molecular pollutants in water. The electrospun SiO₂ fibrous membrane is serves as the substrate for hydrothermal depositing CuO-ZnO nanosheets. The CZS nanofibrous membrane shows good adsorption characteristics for Congo red due to the hierarchical morphology and the adsorption kinetics where isotherm follows the pseudo-second-order model and Langmuir model, respectively. The maximum adsorption capacity for Congo red is 141.8 mg/g. Moreover, the membrane exhibits excellent catalytic reduction activity for 4-nitrophenol under mild conditions and over 96% of the pollutants are degraded within 90 s. The CZS nanofibrous membrane has promising prospects in applications in water treatment and environmental protection because of the good flexibility, easy fabrication, excellent adsorption, and catalytic activity.