Imidazole-2yl-Phosphonic Acid Derivative Grafted onto Mesoporous Silica Surface as a Novel Highly Effective Sorbent for Uranium(VI) Ion Extraction

Abstract

A new imidazol-2yl-phosphonic acid/mesoporous silica sorbent (ImP(O)(OH)/SiO) was developed and applied for uranium(VI) ion removal from aqueous solutions. The synthesized material was characterized by fast kinetics and an extra-high adsorption capacity with respect to uranium. The highest adsorption efficiency of U(VI) ions was obtained for the reaction system at pH 4 and exceeded 618 mg/g. The uranium(VI) sorption proceeds quickly in the first step within 60 min of the adsorbent sites and ion interactions. Moreover, the equilibrium time was determined to be 120 min. The equilibrium and kinetic characteristics of the uranium(VI) ions uptake by synthesized sorbent was found to follow the Langmuir-Freundlich isotherm model and pseudo-second-order kinetics rather than the Langmuir, Dubinin-Radushkevich, and Temkin models and pseudo-first-order or intraparticle diffusion sorption kinetics. The adsorption mechanism for uranium on the sorbent was clarified basing on the X-ray photoelectron spectroscopy (XPS) analysis. The model of UO binding to surface of the sorbent was proposed according to the results of XPS, i.e., a 1:1 U-to-P ratio in the sorbed complex was established. The regeneration study confirms the ImP(O)(OH)/SiO sorbent can be reused. A total of 45% of uranium ions was determined as originating from the sorbent leaching in the acidic solutions, whereas when the basic solutions were used, the removal efficiency was 12%.

Self‐assembled biogenic melanin modulated surface chemistry of biopolymers‐colloidal silica composite porous matrix for the recovery of uranium

“…Therefore, when the pH of the solution was in the range of 5–7, it is suggestive to be strong complex formation of uranyl ions to the carboxyl and amine groups of matrix (see the proposed ion‐exchange mechanism; Scheme 2) . Formation of these complexes and the significance of carboxyl and amine groups in metal binding have been addressed in previous published studies …”

Extraction and adsorption of U(VI) from aqueous solution using affinity ligand-based technologies: an overview

“…Phosphines with imidazol-2-yl moiety, which is the ligand of many transition metals, has been successfully immobilized onto adsorbents for uranium removal. The work has been reported by Budnyak et al with a continuous process (Budnyak et al 2016(Budnyak et al , 2018. Firstly, Benzoimidazol-2-yl-phenylphosphinic acid was immobilized on the silica as adsorbents for uranyl ions (Fig.…”

“…The removal of benzene ring from the phosphines release the potential of phosphine coordinating with uranyl ions alone. This adsorbent was applied in acidic environment for uranium removal with a highest adsorption capacity exceeding 618 mg g -1 at pH 4 (Budnyak et al 2018).…”

“…The presence of Fig. 7 The schematic structures and uranium adsorption mechanism of silica with immobilized benzoimidazol-2-ylphenylphosphinic acid (Budnyak et al 2016) (a) or imidazol-2yl-phosphonic acid (Budnyak et al 2018) calix-NMG in the nanofibers converted the hydrophobic properties into hydrophilic, and increased its chelating ability of uranyl ions. Additionally, the durability advantages of this fiber made it feasible in separation.…”

Efficient Removal of U(VI) Using Functionalized Hollow Mesoporous Silica Nanospheres

“…For example, Budnyak et al. found midazole‐2yl‐phosphonic acid derivative grafted mesoporous silica can effectively remove U(VI) from aqueous solutions with extra‐high adsorption capacity and fast kinetics . Wang and co‐workers studied the solid phase extraction of U(VI) using amidoxime‐functionalized mesoporous silica nanospheres .…”