Highly Porous Acrylonitrile-Based Submicron Particles for UO₂²⁺ Absorption in an Immunosensor Assay

Abstract

Our laboratory has previously reported an antibody-based assay for hexavalent uranium (UO(2)(2+)) that could be used on-site to rapidly assess uranium contamination in environmental water samples (Melton, S. J.; et al. Environ. Sci. Technol. 2009, 43, 6703-6709). To extend the utility of this assay to less-characterized sites of uranium contamination, we required a uranium-specific adsorbent that would rapidly remove the uranium from groundwater samples, while leaving the concentrations of other ions in the groundwater relatively unaltered. This study describes the development of hydrogel particles containing amidoxime groups that can rapidly and selectively facilitate the uptake of uranyl ions. A miniemulsion polymerization technique using SDS micelles was employed for the preparation of the hydrogel as linked submicrometer particles. In polymerization, acrylonitrile was used as the initial monomer, ethylene glycol dimethacrylate as the crosslinker and 2-hydroxymethacrylate, 1-vinyl-2-pyrrolidone, acrylic acid, or methacrylic acid were added as co-monomers after the initial seed polymerization of acrylonitrle. The particles were characterized by transmission electron spectroscopy, scanning electron microscopy (SEM) and cryo-SEM. The amidoximated particles were superior to a commercially available resin in their ability to rapidly remove dissolved UO(2)(2+) from spiked groundwater samples.

Amidoximated poly(acrylonitrile) particles for environmental applications: Removal of heavy metal ions, dyes, and herbicides from water with different sources

“…HCl, and the reaction was continued at 80°C for 24 h. Upon amidoximation, the milky color p(AN) particles turned light yellow as can be seen from digital camera images of p(AN) and amid‐p(AN) given in Figure (a). This color change from milky white to light yellow as a result of the amidoximation reaction can be attributed to the amidoximation reaction and the more hydrophilic nature of amid‐p(AN) particles . A similar color change was also observed by Neghlani et al .…”

“…By increasing the amount of adsorbent, the number of sites available for adsorption of Cd (II) increased so higher amounts of Cd (II) were adsorbed, as illustrated in Figure (b) in terms of % removal. The % removal increased from 13 to 72% by increasing the amount of amid‐p(AN) from 0.025 to 0.0125 g. This is also the case in adsorption studies of most metal ions and/or organic compounds . The % removal of Cd (II) in the present investigation is very high as compared to that reported by Maria et al .…”

“…As monomers with pendent amidoxime groups are not easily available, the most convenient way to obtain amidoxime functional groups is by the conversion of already existing nitriles in monomers such acrylonitrile and/or nitrile contained in cyanoacrylates. Due to the ease of synthesis of polyacrylonitrile (p(AN)), modification via the conversion of nitriles to amidoxime and ability to form complexes with heavy metal ions, poly(acrylonitrile)‐based polymeric structures have been extensively used in the removal of heavy metal ions with different formulations and morphologies . Maria et al .…”

Size‐controlled gold nanoparticles inside polyacrylamide microgels

“…The synthesis of monodisperse AuNPs is also mainly controlled by the number of produced nucleating centers in size‐controlled polymeric network templates. Thus, efforts have been made to obtain microgels with controlled sizes, porosity, and morphology …”

Ionic liquid hydrogel templates: Bulkgel, cryogel, and microgel to be used for metal nanoparticle preparation and catalysis

“…Hydrogels are polymeric networks comprising different functional groups containing monomers with a wide range of applications in biomedical fields and as templates for in situ metal nanoparticle synthesis, such as Co, Au, Cu, Pt, Ru, Ni and as catalysts [10,11]. The sizes, porosity and the morphology of hydrogels can be tuned from mm to nanometer sizes, and the pore size can also be arranged from super porous, hundreds of lm, to microporous, up to 2 nm [11,12]. http …”