Fe(II)ion‐imprinted copolymer gels − smart materials for Fe(II)/Fe(III) speciation in surface waters

Abstract

The effect of template species -Fe(II) complexes with 4-(2-pyridylazo)resorcinol or 2,2 0 -bipyridine as well as the functional monomers: acidic (methacrylic acid) and neutral (hydroxyethyl methacrylate) on the extraction efficiency and applicability of Fe(II) ion-imprinted polymers for iron speciation in surface waters is presented in this study. The polymers were synthesized by precipitation copolymerization of functional monomer, trimethylolpropane trimethacrylate (crosslinking agent) and 2,2 0 -azo-bis-isobutyronitrile (initiator) in the presence of template and characterized by elemental microanalysis, SEM and Brunauer-Emmett-Teller analyses. Extraction efficiency was examined by batch solid-phase extraction. The equilibrium experimental data of adsorption processes with different synthesized sorbents were fitted by both Langmuir and Freundlich isotherms and are discussed from the viewpoint of possible bond formation between monomer and template species and the stability of the prepolymerization complex. Pseudo-first-order and pseudo-second-order kinetic models were tested to elucidate the possible controlling mechanism of the sorption process for different sorbents. Under the optimum conditions pH 7 and equilibrium time of 30 min the highest extraction efficiency and selectivity toward Fe(II) was achieved for Fe(II) ion-imprinted polymer containing methacrylic acid and Fe(II)-4-(2-pyridylazo)resorcinol complex as a template. The analytical procedure for Fe speciation was developed and validated with this sorbent.

Polymeric Materials in Speciation Analysis Based on Solid-Phase Extraction

“…However, the separation of both Fe species was achieved in the presence of fluoride ions as a masking agent for Fe(III). The same group also investigated the effect of template species (Fe(II) complexes with 4-(2-pyridylazo)resorcinol (PAR) or BP) as well as the functional monomers (MAA or HEMA) on the extraction efficiency and applicability of Fe(II)-IIPs for iron speciation in surface water [ 113 ]. All the results indicate that Fe(II)-IIP synthesized with MAA as a functional monomer and Fe(II)–PAR complexes as template species showed the best binding properties and higher selectivity toward Fe(II).…”

Special Issue: Functional Polymers and Composites: From Synthesis to Applications (Dedicated to the 80th Anniversary of Professor George S. Georgiev)

“…Yaroslavov et al 27 discuss the utility of hydrolyzed polyacrylonitrile and cationic polymer for the preparation of inter‐polyelectrolyte complexes that have the potential to suppress the erosion of soils. Ion‐imprinted polymers derived from Fe(II) compounds and functional polymers with hydroxyl or carboxylate groups and their ability to serve as efficient sorbents are described in the work by Dakova, Mitreva, and Karadjova 28 . Next, the fundamentals, i.e., kinetics, thermodynamics, and mechanism of degradation of polycyanoacrylate‐based nanofibers are studied by a research team led by Georgieva and Simeonova 29 .…”

“…Ion-imprinted polymers derived from Fe(II) compounds and functional polymers with hydroxyl or carboxylate groups and their ability to serve as efficient sorbents are described in the work by Dakova, Mitreva, and Karadjova. 28 Next, the fundamentals, i.e., kinetics, thermodynamics, and mechanism of degradation of polycyanoacrylatebased nanofibers are studied by a research team led by Georgieva and Simeonova. 29 Durability of polymers is also the subject of the paper by Harrass, Mauer, and Tsekov 30 who report on the stability and mechanical properties of a polyamide-glass fiber-based composite materials in the presence of ethylene glycol-containing cooling fluids.…”