Jump to main content
Jump to site search


Selective separation of cadmium(II) from zinc(II) by a novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure: a hard–soft donor combined method

Author affiliations

Abstract

A novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure ((IL-1,2-tpbd)+NTf2) was successfully synthesized. (IL-1,2-tpbd)+NTf2 combined one amido (O-hard donor) and four pyridine (N-soft donor) groups. Its Cd2+ and Zn2+ separation behavior in nitric acid solution was investigated as a function of the extraction time, effect of pH etc. by dissolving (IL-1,2-tpbd)+NTf2 in a room temperature ionic liquid, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ((C6mim)+NTf2). The extraction kinetics were fairly fast and could reach equilibrium within 4 h. When pHeq ≥ 1.8, the extraction percentage of Cd2+ and Zn2+ remained constant and the maximum separation factor was calculated as 12.78 at pHeq = 3.1; when pHeq < 1.8, the extraction percentage of Cd2+ and Zn2+ decreased drastically due to the protonation of the pyridine groups. Complete stripping of the extracted Cd2+ and Zn2+ from the ionic liquid phase into an aqueous phase was successfully achieved under highly acidic conditions ([HNO3] = 2 M) without adding any other metal complex forming agents. The extraction mechanism was summarized as a cation exchange due to the independence of nitrate ions in the extraction process. Additionally, the results of the slope analysis and UV-vis titration revealed the formation of a 1 : 2 complex. Furthermore, (IL-1,2-tpbd)+NTf2 showed a higher preference for Cd2+ even under the interference of various co-existing metal ions.

Graphical abstract: Selective separation of cadmium(ii) from zinc(ii) by a novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure: a hard–soft donor combined method

Back to tab navigation

Supplementary files

Publication details

The article was received on 31 May 2018, accepted on 27 Jun 2018 and first published on 28 Jun 2018


Article type: Paper
DOI: 10.1039/C8DT02228C
Citation: Dalton Trans., 2018, Advance Article
  •   Request permissions

    Selective separation of cadmium(II) from zinc(II) by a novel hydrophobic ionic liquid including an N,N,N′,N′-tetrakis(2-methylpyridyl)-1,2-phenylenediamine-4-amido structure: a hard–soft donor combined method

    H. Wu, X. Zhang, X. Yin, Y. Inaba, H. Miki and K. Takeshita, Dalton Trans., 2018, Advance Article , DOI: 10.1039/C8DT02228C

Search articles by author

Spotlight

Advertisements