**Acknowledgements**

The present work was partially supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (Research Program(C), no. 16K00599) and a fund for the promotion of Niigata University

*Advanced Sorption Process Applications*

**Adsorbents** *Q*

*Comparison of the adsorption capacities of LDHs in other literature Cu2+.*

MoS4-LDH—LDHs intercalated with the MoS4

**Adsorbents** *Q*

MNP-CTS—MNPs modified with chitosan (CTS) 140 [43] CL-LDH—LDHs intercalated by chloride 40 [16] CDpoly-MNPs—(CM-β-CD) polymer-modified Fe3O4 nanoparticles 65 [44] H100-LDH—MgAl-LDH intercalated by humate anions 99 [12]

L0 (MgAl-CO3) 78 This study L1 (MgAl-NO3) 58 This study L2 (MgAl-EDTA) 228 This study L3 (MgAl-EDDS) 169 This study L4 (ZnAl-NO3) 80 This study L5 (ZnAl-EDTA) 223 This study

LS-LDH: MgAl-LDH intercalated by sulfonated lignin (LS) 64 [39] TA-HTC: hydrotalcite modified by tannin 81 [40] CL-LDH: LDHs intercalated by chloride 38 [41] H100-LDH: MgAl-LDH intercalated by humate anions 85 [12] Sx-LDH: MgAl-LDH intercalated by polysulfide 127 [42] L0 (MgAl-CO3) 28 This study L1 (MgAl-NO3) 20 This study L2 (MgAl-EDTA) 71 This study L3 (MgAl-EDDS) 59 This study L4 (ZnAl-NO3) 31 This study L5 (ZnAl-EDTA) 90 This study

**(mg g<sup>−</sup><sup>1</sup> )**

**(mg g<sup>−</sup><sup>1</sup> )**

<sup>2</sup><sup>−</sup> ion 290 [45]

**References**

**References**

**178**

**4. Conclusions**

**Table 6.**

**Table 5.**

presented in **Table 5**. Moreover, **Table 6** shows the comparison of adsorption capacity of Pb(II) by other adsorbents reported in the literature. As seen in **Tables 5** and **6**, the adsorption capacity of these LDHs for Cu(II) and Pb(II) in this work is on a level

In present study, LDHs intercalated with chelating agents have been extensively

examined and applied for adsorption of aqueous containing heavy metals and REEs. The following five kinds of compounds were synthesized (MgAl-NO3 (L1), MgAl-EDTA (L2) and MgAl-EDDS (L3), ZnAl-NO3 (L4), ZnAl-EDTA (L5)). These

with that of another adsorbents in previous works.

*Comparison of the adsorption capacities of LDHs in other literature Pb2+.*

KAAB Projects from the Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors are also grateful to Mr. M. Ohizumi of the Office for Environment and Safety in Niigata University, Dr. E. Tayama of Faculty of Science, Dr. M. Teraguchi, Mr. T. Nomoto, Prof. T. Tanaka, and Mr. T. Hatamachi of Faculty of Engineering and Mr. M. Kobayashi of Facility of Dentistry in Niigata University for permitting the use of ICP-AES, elemental analyzer, FT-IR, SEM, specific surface area analyzers, and EPMA and for giving helpful advice in measurement.
