(Ce-Al)-oxide pillared bentonite: A high affinity sorbent for plutonium

Yangchun Leng, Qintang Li, Qiang Tian, Xiaoyuan Chen, László Almásy, Yuliang Liu, Guangai Sun, Xianguo Tuo, Minhao Yan, Mark J. Henderson

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Abstract

The ability of bentonite and montmorillonite pillared by Al-oxide and mixed (Ln-Al)-oxides (Ln = La, Ce) to remove 239plutonium solution species from water is comparatively investigated at pH 7 and pH 4. Small-angle scattering and neutron contrast variation with H2O/D2O mixtures is used to verify the ingress of water in the calcined products after hydrophilicity was introduced by an NH3-H2O vapor treatment. The size and shape of the (La/Ce)-Al oxo-hydroxy pillaring cations (2 nm spheres) is determined by small-angle x-ray scattering from the pillaring solutions. Not all of the oxide pillars improved Pu uptake compared with sodium montmorillonite. At neutral and acidic pH only (Ce-Al)-oxide pillared clays showed the ability to remove Pu over the concentration range studied (1.35 × 10−8–8 × 10−8 mol dm−3) with distribution coefficient (KD) values >104. XPS analysis of the (Ce-Al)-oxide pillared clays indicates the presence of Ce4+ as cerium dioxide. The progressive improvement in sorption performance in the order of pillar type Al2O3 < La2O3-Al2O3 << CeO2-Al2O3 reflects the increasing access of Pu solution species to the clay mineral layers by changes to the basal spacing and specific surface area, and also to the higher stability of the (Ce-Al)-oxide pillars.

Original languageEnglish
Pages (from-to)121-129
Number of pages9
JournalJournal of Hazardous Materials
Volume352
DOIs
Publication statusPublished - Jun 15 2018

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Keywords

  • Cerium dioxide
  • Neutron scattering
  • Pillared clay
  • Plutonium

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

Cite this

Leng, Y., Li, Q., Tian, Q., Chen, X., Almásy, L., Liu, Y., Sun, G., Tuo, X., Yan, M., & Henderson, M. J. (2018). (Ce-Al)-oxide pillared bentonite: A high affinity sorbent for plutonium. Journal of Hazardous Materials, 352, 121-129. https://doi.org/10.1016/j.jhazmat.2018.03.028