Pb²⁺ adsorption behavior of calix[4]arene based Merrifield Resin

Abstract

The present study reveals the adsorption of heavy metals, especially Pb²⁺ from aqueous media by p-tetrathioureacalix[4]arene based Merrifield resin (1). The adsorption behavior of toxic Pb²⁺ metal was evaluated through batch experiments and various parameters such as dosage, concentration and temperature were optimized. From the kinetic study, it has been noticed that adsorption mechanism follows pseudo-second order kinetic model. In addition, thermodynamic constants of adsorption phenomena for Pb²⁺ was found to be ΔH = 0.098 kJ/mol and ΔS = 0.339 kJ/mol, the positive value of ΔH suggest endothermic nature and spontaneity of process estimated by negative value of ΔG. The experimental data was carried out by applying different isotherm equations such as Freundlich, Langmuir, and Dubinin–Radushkevich, (D–R). From the analysis it could be clearly understood that Pb²⁺ has been adsorbed chemically onto the surface of resin (1).In this view, calix[4]arene based resin (1) is very potential in minimize the risk of environmental water pollution by Pb²⁺.

Keywords:

• Calix[4]arene
• Merrifield resin
• Adsorption
• Isotherm equations
• Kinetic study

Acknowledgement

We are highly thankful to National Centre of Excellence in Analytical Chemistry, University of Sindh, for financial support.