Effect of metal ions loaded onto iminodiacetic acid functionalized cation exchange resin for selective fluoride removal

Abstract

In the present work, Duolite (DLE) C 466 (Sodium form of iminodiacetic acid functionalized macroporous cross-linked polystyrene), a commercially available resin has been modified by loading various metal ions like Fe³⁺, Al³⁺, Ce³⁺, and La³⁺ to enhance the fluoride removal capacity of the resin. The effect of pH, dose of adsorbent, contact time, co-ions, and temperature on fluoride removal efficiency was studied. In order to establish the structural modifications, metals loaded DLE resins were characterized by FTIR and SEM−EDAX studies. The sorption data were subjected to Langmuir and Freundlich isotherms, and the sorption process follows Freundlich isotherm. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° indicated that the nature of fluoride sorption is spontaneous and endothermic. Dynamic adsorption data indicated that the pseudo-second-order rate equation is the suitable model for the sorption reaction.

Keywords:

• Adsorption
• Fluoride
• Resin
• Isotherm
• Thermodynamics
• Kinetic model

Acknowledgements

The corresponding author is grateful to Department of Science and Technology (DST/TDT/WTI/2k8/82) New Delhi, India and the first author likes to thank UGC-RFSMS, New Delhi, India for their providing of financial support to carry out this research work.