Microfiltration membrane possessing chelation function and its adsorption and rejection properties towards heavy metal ions

Abstract

AbstractBackgroundRemoving toxic heavy metal ions from water bodies is one of the most important areas of water treatment, and using porous membranes with a chelating function is a good route for this. Graft‐type porous membranes with a chelating function are innovate functional membranes. In this work, the main aims are to prepare such a functional membrane and evaluate its adsorption and rejection properties for heavy metal ions in water through adsorption isotherm experiments and permeation experiments.ResultsGlycidyl methacrylate (GMA) was graft‐polymerized on the surface of polysulfone (PSF) microfiltration membrane through a surface initiating system, getting the grafted membrane PSF‐g‐PGMA. Then the ring‐opening reaction of the epoxy group of the grafted PGMA was carried out with iminodiacetic acid (IDAA) as reagent, obtaining PSF‐g‐PGMA/IDAA membrane, on which a great deal of IDAA as chelating ligand was bonded. PSF‐g‐PGMA/IDAA membrane possesses a strong adsorption ability towards heavy metal ions via the chelating action and electrostatic interaction. The order of adsorption capacity was Pb2+>Cu2+>Cd2+, and the adsorption capacity of Pb2+ ion reached 4.5 µmol cm−2. When an injection filter with a membrane area of 1.77 cm2 was used, the rejection rate of PSF‐g‐PGMA/IDAA membrane for the three heavy metal ions with concentrations of 0.1 mmol L−1 were maintained at a level of 95% until the permeation solution volume reached 100 mL.ConclusionThe grafted microfiltration membrane PSF‐g‐PGMA/IDAA can be easily prepared and possesses excellent rejection and removing performance towards heavy metal ions © 2018 Society of Chemical Industry