Effect of Temperature and Time on Crosslinking Reaction of Fabricating Modified Poly(Vinyl Alcohol) Materials for Pb(II) Removal in Aqueous Solutions

The study aims to evaluate the cross-linking ability of Poly(Vinyl Alcohol) (PVA) membranes with L-glutamic acid through solid-phase esterification reactions to improve water resistance. The cross-linked material exhibits enhanced Pb(II) ion adsorption capacity due to porosity introduced by Poly(Ethylene Glycol) (PEG), which increases surface area and swelling ability. The cross-linking reaction and porosity of the material were demonstrated by the crosslink density of the membrane and the material’s swelling behavior in water. Results show that at 130 °C for 60 minutes, the optimal material was obtained, with a crosslink density of 92.89%. After the addition of PEG, water swelling increased to 131.77%, a 51% increase compared to the system containing only PVA and L-glutamic acid. The PVA-c-glu/PEG membrane exhibited excellent Pb(II) adsorption capacity, with a Qe of 66.29 mg/g at room temperature (30 °C), an initial Pb(II) concentration of 114.08 mg/L, pH 7, and a material mass of 0.05 g in 2 days, compared to untreated PVA, which had a Qe of 11.79 mg/g.