Incorporation of UiO-66-NH2 MOF into the PAN/chitosan nanofibers for adsorption and membrane filtration of Pb(II), Cd(II) and Cr(VI) ions from aqueous solutions

Abstract

In the present study, the UiO-66-NH₂ MOF synthesized by microwave heating method was incorporated into the PAN/chitosan nanofibers for the removal of Pb(II), Cd(II) and Cr(VI) ions through the adsorption and membrane filtration processes. The synthesized MOFs and nanofibers were characterized using XRD, BET, FTIR, SEM, and DSC analysis. The effect of UiO-66-NH₂ MOF content (0-15 wt.%), pH (2-7), contact time(5-90 min), metal ions initial concentration (20-1000 mg/L) and temperature (25-45 °C) was studied on the metal ions adsorption using PAN/chitosan/UiO-66-NH₂ nanofibrous adsorbent. The kinetic, isotherm and thermodynamic parameters were evaluated to understand the metal ions adsorption mechanism using nanofibers. The Pseudo-second-order kinetic and Redlich-Peterson isotherm model were well described the experimental sorption data. In the heavy metal ions membrane filtration process, the different parameters such as MOF concentration (2-15 wt.%), membrane thickness (10-70 μm), metal ions concentration (5-50 mg/L), temperature (25-45 °C) and filtration time (1-24 h) were investigated on the performance of PVDF/ PAN/chitosan/UiO-66-NH₂ nanofibrous membrane toward metal ions removal. The high water flux and high metal ions removal within 18 h filtration time showed the high potential of PVDF/ PAN/chitosan/UiO-66-NH₂ membrane for the removal of metal ions from aqueous solutions.

Keywords: Adsorption; Membrane filtration; PAN/chitosan nanofiber; Regeneration; UiO-66-NH(2)MOF.