In this study, Mg/Al layered double hydroxides (LDHs) were investigated for their potential in scavenging several harmful oxyanions from aqueous solution. LDHs could effectively remove oxyanions and the selectivity of LDHs was governed by both the valencies and the ionic radii of the oxyanions. LDHs prepared by the fast coprecipitation with hydrothermal treatment (FCHT) method and sol-gel with solvothermal treatment method (SGST) had higher oxyanion (i.e. arsenate) removal efficiency than those prepared by the conventional routes, owing to their lower carbonate content, higher surface area, larger pore volume, larger pore size, and nanocrystalline characteristic. The sorption of arsenate by FCHT-LDH was found primarily due to anion exchange mechanism and might involve a secondary sorption mechanism. The negative ΔG° for arsenate sorption confirmed the spontaneity of the removal process. The positive values of ΔH° and ΔS° provided further evidence of the anion exchange process in the removal mechanism.
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Research Article|
March 01 2009
Mechanistic and thermodynamic studies of oxyanion sorption by various synthetic Mg/Al layered double hydroxides
T. T. Lim;
1School of Civil and Environmental Engineering, Nanyang Technological University, 50, Nanyang Avenue, Singapore, 639789, Singapore E-mail: cttlim@ntu.edu.sg; ckhgoh@ntu.edu.sg; ronn0010@ntu.edu.sg
E-mail: cttlim@ntu.edu.sg
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K. H. Goh;
K. H. Goh
1School of Civil and Environmental Engineering, Nanyang Technological University, 50, Nanyang Avenue, Singapore, 639789, Singapore E-mail: cttlim@ntu.edu.sg; ckhgoh@ntu.edu.sg; ronn0010@ntu.edu.sg
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R. Goei;
R. Goei
1School of Civil and Environmental Engineering, Nanyang Technological University, 50, Nanyang Avenue, Singapore, 639789, Singapore E-mail: cttlim@ntu.edu.sg; ckhgoh@ntu.edu.sg; ronn0010@ntu.edu.sg
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Z. L. Dong
Z. L. Dong
2School of Materials Science and Engineering, Nanyang Technological University, 50, Nanyang Avenue, Singapore, 639789, Singapore zldong@ntu.edu.sg
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Water Sci Technol (2009) 59 (5): 1011–1017.
Citation
T. T. Lim, K. H. Goh, R. Goei, Z. L. Dong; Mechanistic and thermodynamic studies of oxyanion sorption by various synthetic Mg/Al layered double hydroxides. Water Sci Technol 1 March 2009; 59 (5): 1011–1017. doi: https://doi.org/10.2166/wst.2009.072
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