Stabilized nanofibers of polyvinyl alcohol (PVA) crosslinked by unique method for efficient removal of heavy metal ions

Abstract

Removal of heavy metal ions is vital in water purification system. In this report we designed a unique method to crosslink polyvinyl alcohol (PVA) nanofiber to enhance its adsorption capacity against metal ions like Copper (Cu2+) and Lead (Pb2+). PVA nanofibers were crosslinked by conventional method using glutaraldehyde vapors and also by solution method (self-designed). Morphological properties were examined by scanning electron microscope (SEM) which confirmed uniform morphology of nanofiber membranes. Thermal degradation analysis was done using thermogravimetric analyzer (TGA). Mechanical properties were also improved significantly in case of solution crosslinked PVA nanofibers. X-Ray diffraction results showed that crystallinity was also increased when nanofibers were crosslinked using solution method. Fourier transform infrared spectroscopy (FTIR) was performed to check bonding of hydroxyl group in the result of crosslinking and it was confirmed that more hydroxyl groups were bound in case of solution crosslinked PVA nanofibers. Adsorption capacity for copper and lead ions was measured using inductively coupled plasma (ICP) atomic emission spectrometer and it was concluded from adsorption data that solution crosslinked PVA nanofibers were far efficient as compared to that of uncrosslinked and vapor crosslinked nanofibers. Equilibrium time was decreased significantly which gives credibility of process with efficient removal of metal ions in shorter time.