Multifunctional superhydrophobic electrospun recycled PVC membranes on polyester support with mineral and carbon additives for Oil–Water separation and ionic attenuation

The design of polymer composites from recycled materials requires careful control over structure at different length scales. In this work, post-consumer polyvinyl chloride (PVC) was transformed into a textile-supported electrospun nanofibrous composite reinforced with calcium carbonate (CaCO ₃ ), hydroxyapatite (HAp), and carbon nanotubes (CNTs). The electrospun layer was deposited directly onto a polyester substrate, creating a mechanically integrated structure in which the fibrous network and the textile support function together. Twelve formulations were prepared to understand how gradual filler incorporation influences solution behavior, fiber formation, and mechanical response. The composition containing 15 wt% PVC with 8 wt% CaCO ₃ , 2 wt% HAp, and 2 wt% CNTs provided the most stable performance, reaching a tensile strength of 42.97 ± 2.15 MPa and an elongation at break of 33.78 ± 1.75%. The improvement did not result from a single additive. CaCO ₃ contributed structural rigidity, HAp introduced dispersed ceramic domains within the matrix, and CNTs enhanced load transfer while modifying surface roughness. Their combined presence led to a more cohesive fibrous architecture without noticeable embrittlement. The optimized composite maintained a highly porous structure (∼90%) with limited water uptake (∼5%) and exhibited a stable superhydrophobic surface (156.76 ± 1.00°). Under gravity-driven conditions, the membrane achieved 94% oil–water separation. During static immersion in a laboratory-prepared NaCl solution, conductivity decreased by 80.7% after 60 minutes. These results reflect how filler dispersion and hierarchical structuring influence both mechanical stability and interfacial transport behavior within the composite.