Surface ion imprinting-mediated carbon nanofiber-grafted highly porous polymeric beads: Synthesis and application towards selective removal of aqueous Pb(II)

Abstract

Novel Pb(II) ion-imprinted and carbon nanofibers (CNFs)-grafted highly porous (∼475m2/g) polymeric beads (∼0.5mm) were prepared by the surface ion imprinting technique. The allylthiourea precursor-based polymeric beads were synthesized by suspension polymerization, in which CNFs were in-situ mixed during the polymerization reaction before the curing step. The prepared ion-imprinted and CNF-grafted polymeric (CNF-IIP) beads were used for the efficient and selective removal of Pb(II) ions from aqueous solution by adsorption. The adsorption capacity of the CNF-IIPs for Pb(II) ions was determined to be ∼47mg/g. The material exhibited high selectivity for Pb(II) in the presence of the Ni(II), Zn(II) and Cd(II) competitive ions, with the selectivity coefficients for the Pb(II)/Ni(II), Pb(II)/Zn(II) and Pb(II)/Cd(II) in binary systems determined to be ∼48, 28 and 14, respectively. The synthesized CNF-IIP adsorbents were easily regenerated by acid treatment and used in five adsorption/regeneration cycles. The method described in this study can be applied for the development of the similar CNF-IIPs for the selective removal of various toxic metal ions present in industrial effluents.