Comparative study: Correlating extraction efficiency for Hg(II), Cd(II), and Pb(II) metal ions with the chelate stability and total hardness in simple nitrogen donors

ABSTRACT

Four N-donors (PHDA, ATPH, APHO, and MTAN) containing NH₂ were used to extract Hg(II), Cd(II), and Pb(II). Their extraction capacity was determined by measurement of percentage extraction.

The chelates extract these metals differently: for example, efficiency of ATPH was the highest for Hg(II) compared to PHDA, APHO, and MTAN.

The extraction efficiency was found to depend on: donor atom hardness, chelate total hardness, metal: chelate mole ratio and substituent’s electronic effects. Among all, total hardness and chelate stability are key factors and molecule of small (E_HOMO – E_LUMO) is more reactive, where extraction efficiency increases as molecular stability decreases.

KEYWORDS:

• Cadmium
• chelation
• extraction capacity
• lead
• mercury
• nitrogen donors

Acknowledgements

The author express great thanks for Department of Biology, Chemistry and Environmental Sciences, American University of Sharjah, Sharjah, UAE for helping in theoretical calculations and for the Department of Chemistry-Jordan University of Science and Technology (JUST) for providing instrumentation.

Funding

This work was financially supported by the Faculty of Graduate Studies and Scientific Research Yarmouk University [grant number 13/2015].

Additional information

Funding

This work was financially supported by the Faculty of Graduate Studies and Scientific Research Yarmouk University [grant number 13/2015].