synthesis of piperdinomethylcalix[4]arene attached silica resin for the removal of metal ions from water: equilibrium, thermodynamic and kinetic modelling studies

Toxic metal pollution is one of the most persistent environmental problems globally. this study deals with the synthesis of the p-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 cu^2+ and pb^2+ metal ions. to examine the adsorption mechanism and validate the experimental adsorption data the isotherm models were applied and adsorption of the cu^2+ and pb^2+ 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 cu^2+ and pb^2+, respectively. furthermore, thermodynamics and kinetic study revealed that, the adsorption process spontaneity and endothermic that follows the pseudo 2nd order kinetic equation with good regression coefficient.