Nanofiber PVA-Based Membranes Incorporating Functionalized Spanish Broom Derivatives for Sustainable Water Purification

This study explores the use of Spanish broom (Spartium junceum) to develop electrospun composite membranes, showcasing the potential of renewable plant waste for producing eco-friendly, high-value materials for innovative gravity-driven water purification. In this sustainable approach, first of all, microcrystalline cellulose and biochar were successfully obtained from this natural source and functionalized using an easy, eco-friendly, and one-step synthesis by employing proper precursors and nanomaterials, that is, (3- mercaptopropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, citric acid, β-Cyclodextrins, and halloysite nanotubes, to prepare green, hybrid, and cross-linked systems featuring tailored properties. The obtained derivatives were characterized and employed for the further development of eco-friendly and sustainable poly(vinyl alcohol) nanofiber composites through the electrospinning technique on nonwoven glass microfiber support. After thermal treatment, the membranes displayed enhanced mechanical tensile properties and were tested in a dead-end filtration cell for the removal of a methylene blue and methyl orange mixed solution, in particular demonstrating high retention and separation performances toward the cationic methylene blue dye. Among all, the PVA@MCC_GPTMS_HNT and PVA@MCC membranes achieved methylene blue retention rates of 93.4% and 79.9%, methylene blue/methyl orange separation efficiencies of 93.5% and 82.1%, and fluxes of 133.7 and 501.7 Lm2 h1, respectively. Moreover, a biochar-supported nano zero-valent iron composite was obtained and tested for the removal of MB in batch experiments. The Langmuir adsorption isotherm model better describes its sorption behavior with a maximum sorption capacity of 305.65 mg g1.