Iron phosphonate for highly efficient capture of U(VI) from acidic solution

Jiao Tang; Junxiang Tang; Hao Lei; Yong Chen; Jiang Zhao; Xiaoqiang Wang; Ning Pan

doi:10.1016/j.scitotenv.2021.151005

Iron phosphonate for highly efficient capture of U(VI) from acidic solution

Sci Total Environ. 2022 Feb 10;807(Pt 3):151005. doi: 10.1016/j.scitotenv.2021.151005. Epub 2021 Oct 16.

Authors

Jiao Tang¹, Junxiang Tang², Hao Lei³, Yong Chen², Jiang Zhao², Xiaoqiang Wang⁴, Ning Pan⁵

Affiliations

¹ Fundamental Science on Nuclear Wastes, Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang 621010, China; School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China.
² School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China.
³ Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, China.
⁴ Fundamental Science on Nuclear Wastes, Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang 621010, China; School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China. Electronic address: wangxiaoqiang@swust.edu.cn.
⁵ Fundamental Science on Nuclear Wastes, Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang 621010, China.

PMID: 34662619
DOI: 10.1016/j.scitotenv.2021.151005

Abstract

In this study, a novel, high surface area iron phosphonate (IP) for highly efficient adsorption of uranyl ion in acidic medium was described. The as-prepared IP was amorphous with its specific surface area and total pore volume as high as 268 m²/g and 1.04 cm³/g, respectively. Particularly, the as-prepared IP with ferrous ions and oxygen, nitrogen-bearing functional groups prove excellent U(VI) adsorption capacity (154.6 mg/g) as compared to that of amorphous FePO₄ (67.3 mg/g) and Fe₃(PO₄)₂(H₂O)₈ (33.8 mg/g). Surprising, the saturation adsorption capacity could achieve up to 353.9 mg/g. Besides, the IP also had a fast adsorption rate for attaining adsorption equilibrium within 20 min, and followed pseudo-second-order kinetic and Freundlich models. Moreover, both the Dubinin-Radushkevich isotherm adsorption model and the value of enthalpy indicated a chemisorption process. Otherwise, the Na⁺-independent U(VI) adsorption on IP and the adsorption-desorption isotherm studies revealed that inner-layer surface complexation is the control step for U(VI) adsorption process, and the adsorbent featured an irreversible adsorption process. The structure and functional groups of the adsorbent remained unchanged after capture of U(VI). Further, X-ray photoelectron spectra (XPS) analysis demonstrated that the capture mechanism of U(VI) on IP from acidic aqueous solution was due to not only redox reaction, but also ascribed to the coordinated chemical adsorption.

Keywords: Adsorbent; Capture; Iron phosphonate; Mechanism; Uranium(VI).

MeSH terms

Adsorption
Iron*
Nitrogen
Organophosphonates*
Water

Substances

Organophosphonates
Water
Iron
Nitrogen