Mechanistic insights into sequestration of U(VI) toward magnetic biochar: Batch, XPS and EXAFS techniques

Qingyuan Hu; Yuling Zhu; Baowei Hu; Songhua Lu; Guodong Sheng

doi:10.1016/j.jes.2018.01.013

Mechanistic insights into sequestration of U(VI) toward magnetic biochar: Batch, XPS and EXAFS techniques

J Environ Sci (China). 2018 Aug:70:217-225. doi: 10.1016/j.jes.2018.01.013. Epub 2018 Feb 2.

Authors

Qingyuan Hu¹, Yuling Zhu¹, Baowei Hu², Songhua Lu³, Guodong Sheng⁴

Affiliations

¹ College of Life Science, College of Chemistry and Chemical Engineering, Shaoxing University, Zhejiang 312000, China.
² College of Life Science, College of Chemistry and Chemical Engineering, Shaoxing University, Zhejiang 312000, China. Electronic address: hbw@usx.edu.cn.
³ Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031, China.
⁴ College of Life Science, College of Chemistry and Chemical Engineering, Shaoxing University, Zhejiang 312000, China. Electronic address: gdsheng@usx.edu.cn.

PMID: 30092964
DOI: 10.1016/j.jes.2018.01.013

Abstract

The magnetic iron oxide (Fe₃O₄) nanoparticles stabilized on the biochar were synthesized by fast pyrolysis of Fe(II)-loaded hydrophyte biomass under N₂ conditions. The batch experiments showed that magnetic biochar presented a large removal capacity (54.35mg/g) at pH3.0 and 293K. The reductive co-precipitation of U(VI) to U(IV) by magnetic biochar was demonstrated according to X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption near edge structure analysis. According to extended X-ray absorption fine structure analysis, the occurrence of U-Fe and U-U shells indicated that high effective removal of uranium was primarily inner-sphere coordination and then reductive co-precipitation at low pH. These observations provided the further understanding of uranium removal by magnetic materials in environmental remediation.

Keywords: Magnetic biochar; Sequestration; Uranium; X-ray absorption spectroscopy.

MeSH terms

Adsorption
Charcoal / chemistry*
Environmental Restoration and Remediation
Ferric Compounds / chemistry
Magnetics
Models, Chemical*
Nanoparticles / chemistry
Photoelectron Spectroscopy
Uranium / chemistry*
X-Ray Absorption Spectroscopy
X-Ray Diffraction

Substances

Ferric Compounds
biochar
Charcoal
ferric oxide
Uranium