Metal Ion-Imprinted Microspheres Prepared by Reorganization of the Coordinating Groups on the Surface

Abstract

the Editor Keywords Imprinting polymerization, carboxylated microspheres, seeded emulsion polymerization, metal ion, selective adsorption of copper(II) and nickel (II) adsorption ofThe development of new materials for separation and concentration is a key step for progress in analytical science. A molecular imprinting technique) is one promising way to prepare highly-selective host polymers, since it requires neitherr precise molecular design nor multi-step procedures for host preparation. The imprinting technique is thus a practical method, in contrast with "supramolecular design".2,3 However, it has some fundamental problems: for example, the inapplicability to use a water-soluble substance as a guest and the need to grind and sieve the formed polymer before use. These problems result from the fact that the host preparation was made from solution . or bulk polymerization using an organic solvent or organic monomer, respectively. On the other hand, polymer microsphere and its aqueous dispersion have become of interest as highly-functional materials.4 A microsphere of submicron diameter is characterized by a large surface area, comparable with porous glass beads, and show a high reactivity near the surface.We now propose a new technique in which molecular imprinting is conducted on the microsphere surface; the imprinted microsphere is synthesized by seeded emulsion polymerization in water. Complexation between guest molecule and functional groups on the microsphere surface takes place through the reorganization of the groups while adapting to the imprinted structure. The new technique is, in principle, applicable to water-soluble substances, such as biological components; the polymer beads are well defined and uniform. Grinding and sieving are not necessary. In addition, this technique would improve the complexation behavior (such as capacity, reaction rate, and selectivity) owing to the unique features of sub-micron spheres.In this study, a heavy metal ion was adopted as a guest and a metal ion-imprinted structure was constructed on the carboxylated microsphere surfaces with the aid of the interaction between the metal ion and the carboxyl groups.The adsorption of metal ions onto the microsphere was examined and the imprinting effect was characterized. ExperimentalThe metal ion-imprinted microsphere was prepared according to Scheme 1. Seed emulsion (2) was obtained by the polymerization of styrene (S) (20.55 g), butyl acrylate (BA) (2.71 g), and methacrylic acid (MAA) (1.64 g), in water (75 g) at pH 2.2 (125 mg of K2S208 as initiator, 70° C, 7 h). The polymerization mixture was then brought to room temperature. Divinylbenzene (DVB) (29.86 g), BA (2.9 g), and water (95 g) were added and the emulsion was left at 2° C for 24 h at pH 9.5. The pH of the mixture was then lowered to 5.0, and a portion (8 cm3) of the emulsion was combined with 40 ml of a metal ion solution (0.01 mol dm-3 Cu(II) or Ni(II)) to achieve complexation between the metal ion and the carboxyl group on the surface (4). The DVB-containing emul...

Preparation and application of Ni(ii) ion-imprinted silica gel polymer for selective separation of Ni(ii) from aqueous solution

“…The key point of this technique is xing binding sites onto the support surface, enabling the target metal ions to combine with binding sites more quickly and easily. 17,18 Therefore, surface ionimprinted polymers not only possess high selectivity and adsorption capacity, but also have a faster mass transfer and binding kinetics. 19 To date, a lot of Ni(II) ion-imprinted polymers based on biomass have been prepared by surface imprinting technique for removal of nickel(II) from aqueous solution.…”

Preparation and Evaluation of Uniform-size (-)-Ephedrine-imprinted Polymeric Microspheres by Multi-step Swelling and Suspension Polymerization

“…16,17 However, as an HPLC packing material, it is of low column efficiency and higher column pressure. To overcome these problems, spherical MIPs (SMIPs) were prepared using different strategies, such as precipitation polymerization, 18,19 suspension polymerization, 20,21 emulsion polymerization, 22,23 polymerization inside the pores of performed silica beads 4 etc. Among them, a multi-step swelling and suspension polymerization method serves to better control the MIP particles and be accessible to modify particles with a hydrophilic layer.…”

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

“…[570][571][572][573][574][575][576][577][578][579][580][581][582][583][584] The preparation of similar surface-imprints for metal ions in a seeded emulsion polymerization was described by Takagi and coworkers. [585][586][587][588] Other reports also describe metal-ion imprinting in organic polymers. [589][590][591][592] The possibility of using waste biomass, for example the mycelium of Penicillium chysogenum, as a supportive matrix which was surface coated with chitosan in the presence of Ni 2þ has recently been investigated.…”