This study reports the design, fabrication, and performance evaluation of a novel class of adsorptive ultrafiltration (UF) membranes based on polyvinyl chloride (PVC) nanofibers reinforced with thiol-functionalized titanate nanotubes (TNT/SH). The primary objective was to develop a scalable, reusable, and high-efficiency membrane system capable of dynamically removing toxic Cu(II) and Ni(II) ions from aqueous solutions under varying operational conditions. The approach leverages the synergistic advantages of electrospun nanofibers—high surface area, tunable porosity, and mechanical robustness—combined with the selective metal-binding properties of thiol-modified inorganic nanoadsorbents.
Titanate nanotubes were synthesized via a hydrothermal method using TiO₂ powder and NaOH, resulting in tubular nanostructures with high surface area and ion-exchange capacity. These TNT were then functionalized with 3-mercaptopropyltrimethoxysilane (MPTMS), which introduced reactive thiol (-SH) groups onto their surfaces through a condensation reaction involving silanol and surface hydroxyl groups. The modified TNT were uniformly dispersed in a PVC solution and electrospun directly onto a pre-formed PVC sublayer prepared by phase inversion. This two-step process yielded a dual-layer composite membrane with an interconnected porous nanofiber mat supported by a macrovoid-rich substructure.
Advanced characterization confirmed successful modification and integration. X-ray photoelectron spectroscopy (XPS) revealed distinct S 2p peaks at 163.5 eV and 164.5 eV, confirming the presence of free thiol groups. Fourier-transform infrared spectroscopy (FTIR) showed characteristic absorption bands at ~2564 cm⁻¹ (S–H stretch), 2852 cm⁻¹ and 2922 cm⁻¹ (C–H stretches), and 1075–802 cm⁻¹ (Si–O–Si vibrations), providing strong evidence of covalent grafting. Field emission scanning electron microscopy (FESEM) displayed uniform, bead-free nanofibers with average diameters between 328 nm and 391 nm, depending on nanoparticle loading. Energy-dispersive X-ray spectroscopy (EDX) and elemental mapping confirmed homogeneous distribution of Ti, S, and Cu across the membrane surface after metal ion uptake.
In continuous UF experiments, the membrane containing 1.5 wt% TNT/SH achieved exceptional removal efficiencies: 90% for Cu(II) and 86.7% for Ni(II) within the first minute of contact time. This performance surpassed that of membranes with unmodified TNT and lower loadings, demonstrating the critical role of thiol functionalization in enhancing adsorption capacity. The removal efficiency remained stable even at elevated temperatures (up to 45°C), indicating an endothermic adsorption process driven by increased diffusion and activation of binding sites.
In competitive ion studies, the presence of Zn(II) had minimal impact on Cu(II) removal but caused a more pronounced decline in Ni(II) uptake, consistent with the selectivity order Cu(II) > Zn(II) > Ni(II), which aligns with HSAB theory and electronegativity trends.Ethyl 3-phenylpropanoate supplier The strong chelating ability of thiol groups toward soft metal cations like Cu(II) enhances both affinity and specificity.ZBP1 ProteinFormulation
The membrane demonstrated excellent reusability over four regeneration cycles using 0.PMID:35084365 05 M HCl. After each cycle, Cu(II) removal remained above 85%, and Ni(II) removal stayed around 76%, indicating minimal degradation of active sites and structural integrity. This stability is attributed to strong covalent bonding between the silane modifier and TNT surface, preventing leaching during operation.
Compared to other reported electrospun membranes, this system achieves higher dynamic removal efficiencies under realistic conditions, validating the effectiveness of thiol functionalization in improving both capacity and selectivity. The scalable fabrication process, combined with high performance, durability, and reusability, positions these membranes as a viable and sustainable solution for industrial wastewater treatment. This work advances the development of next-generation hybrid membranes for efficient heavy metal remediation.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com