Chitosan-coated electrospun PVDF-ZnO nanofibrous membranes for dye wastewater separation

Dye-containing wastewater causes severe environmental pollution, posing a major challenge to existing water treatment methods. Advanced dye separation technology has emerged to solve this problem. Conventional polyvinylidene fluoride (PVDF) membrane is susceptible to fouling during dye removal due to its low surface free energy and strong hydrophobicity. To improve the hydrophilicity of PVDF, nanofibrous membranes with multilevel roughness are prepared by electrostatic spinning using chitosan (CS) and PVDF-nano-zinc oxide blended solution as raw materials. The adsorption performance of the membranes is evaluated when the ZnO content varies from 0 to 1.2 wt%. When the optimized membrane is used to treat Rhodamine B wastewater, its flux and retention rate reach 580.42 L•m −2 •h and 96.33%, respectively (43.94% and 30.12% higher than those of a blank membrane). The flux recoveries are 69.67% for methyl orange and 67.35% for Rhodamine B (25.83% and 36.03% higher than those of a blank membrane, respectively). The irreversible fouling degrees are 30.33% for methyl orange and 32.65% for Rhodamine B, significantly lower than those of a blank membrane (70.51% and 70.07%, respectively).