Synthesis of Piperdinomethylcalix[4]arene Attached Silica Resin for the Removal of Metal Ions from Water: Equilibrium, Thermodynamic and Kinetic Modelling Studies

Abstract

Toxic metal pollution is one of the most persistent environmental problems globally. This study deals with the synthesis of the <em>p</em>-piperdinomethyl calix[4]arene attached silica (PAS) resin and to investigate their metal ions removal efficiency from water. In batch adsorption experiment PAS resin shows good adsorption efficacy for the Cu²⁺ and Pb²⁺ metal ions. To examine the adsorption mechanism and validate the experimental adsorption data the isotherm models were applied and adsorption of the Cu²⁺ and Pb²⁺ metal ions follow Freundlich isotherm model very well with good correlation coefficient. However, the adsorption energy calculated from the D-R isotherm was at the range of 9-14 KJ/mole which describes the ion exchange nature of resin. Furthermore, breakthrough capacity of column was calculated from online adsorption as 0.027 and 0.041 mmol/g^-1 for Cu²⁺ and Pb²⁺, respectively. Furthermore, thermodynamics and kinetic study revealed that, the adsorption process spontaneity and endothermic that follows the pseudo 2^nd order kinetic equation with good regression coefficient.