Uptake of heavy metal ions in layered double hydroxides and applications in cementitious materials

Experimental evidence and first-principle study

Journal article (2019)

Authors

Bo Li Wuhan University of Technology
Shizhe Zhang Materials and Environment - CEG
Qiu Li Wuhan University of Technology
Neng Li Wuhan University of Technology
Bo Yuan Wuhan University of Technology
Wei Chen Wuhan University of Technology
H.J.H. Brouwers Eindhoven University of Technology, Wuhan University of Technology
Qingliang Yu Eindhoven University of Technology
Research Group
Materials and Environment (CEG) (TU Delft)
Copyright: © 2019 Bo Li, Shizhe Zhang, Qiu Li, Neng Li, Bo Yuan, Wei Chen, H.J.H. Brouwers, Qingliang Yu
DOI
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https://doi.org/10.1016/j.conbuildmat.2019.06.135
Layered double hydroxides First principle calculation Heavy metal ions Solid state NMR
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Published Date

2019

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Materials- Mechanics- Management & Design

Research Group

Materials and Environment

Abstract

The uptake mechanism of heavy metal ions in layered double hydroxides (LDHs) is investigated in this paper via solid-solution exchange experiments and first principle study. The uptake capacities of C-LDHs for heavy metal ions from solutions are experimentally investigated and the structures of LDHs doped with various heavy metal ions are revealed. The doped structures of LDHs are further re-established with first principle calculations. The results show that Cu2+ or Cr3+ ions are immobilized in the form of isomorphic substitution for Mg2+ and Al3+ in the plate of the layered structure, respectively, during reconstruction of calcined LDHs, forming a non-stoichiometric structure. The structure of the Cu2+ doped LDHs is identified as [Mg2+ (1−x)(1−z)Cu2+ (1−x)zAl3+ x(OH)2] An− x/n·yH2O, where z is the molar ratio of Cu2+ to Mg2+. The structure of Cr3+ doped LDHs is identified as [Mg2+ 1−x Cr3+ xzAl3+ x(1−z)(OH)2] An− (x+z)/n·yH2O, where z is the molar ratio of Cr3+ to Al3+. The Cu2+ or Cr3+ ions in the hardened cement paste modified with calcined Mg-Al LDHs as immobilizing admixture can be efficiently removed from the pore solution and chemically stabilized in the structure of LDHs.