Effect of Crosslinker Chemical Structure and Monomer Compositions on Adsorption of Uranium (VI) Ions Based on Reactive Crosslinked Acrylamidoxime Acrylic Acid Resins

Abstract

Adsorption capacities of uranyl ions using crosslinked acrylamidoxime acrylic acid (Am/AA) resins composed from acrylonitrile (AN), acrylic acid (AA), having different molar ratios were determined. The AN/AA molar ratios were 80/20, 50/50 crosslinked with 10% N,N 0 -methylenebisacrylamide (MBA) and divinylbenzene (DVB). Polymerization was occurred in the presence of potassium persulfate and sodium metabisulfite as redox initiator. Reaction of synthesized resins with hydroxyl amine in basic media yield polyacryl acrylamidoxime acrylic acid (Am/ AA). The chemical structure of the AN/AA and Am/AA resins, before and after loaded with uranyl ions and after elution, was confirmed by FTIR analysis. The effect of UO 2þ 2 ions sorption on the morphologies of the prepared resins was examined by scanning electron microscope (SEM). Effects of pH, time of loading, type of acid, molar ratio, and type of crosslinker were investigated. Elution of adsorbed ions on resins was investigated by different eluents. The elution efficiency was determined.

Controlled bi-functionalization of silica microbeads through grafting of amidoxime/methacrylic acid for Sr(II) enhanced sorption

“…After acrylonitrile grafting (in both homo-and hetero-polymer), some sp ecific p eaks a p p ear i ncluding n itrile g roup s 2280-2240 cm −1 [69,70]. Carboxylate group s associated to the incorp oration of MAA (both in homo-and hetero-polymers) are identified at 1750-1725 cm −1 [70][71][72].…”

Efficient removal of uranium, cadmium and mercury from aqueous solutions using grafted hydrazide-micro-magnetite chitosan derivative

“…With the increase of the pH, functional groups progressively deprotonate and electron pairs on chelating groups (bearing N and O donor groups) become available on the sorbent [63,64]. It is noteworthy that the tautomerization effect on amide and imine groups (see Section IV, AMS) makes possible the formation of two types of complexes (monodentate and bidentate) with positively charged species.…”

Zero valent iron/poly(amidoxime) adsorbent for the separation and reduction of U(vi)

“…U(VI) mainly exists as the prevailing species of free uranyl (UO 2 2+ ) up to pH 4.5, and then U(VI) hydrolysis complexes and U(VI) multinuclear hydroxide complexes become to be important existing forms of U(VI). Meanwhile, PAO is protonated at low pH values, 34,35 which can hinder U(VI) adsorption on ZVI/PAO surface, which can explain the poor U(VI) adsorption at low pH values. As pH value increases, the protonation degree of adsorption sites and the electrostatic repulsion are gradually decreased, which can enhance U(VI) adsorption on ZVI/PAO at high pH values.…”