KINETICS AND THERMODYNAMIC ASPECT OF THE ADSORPTION OF Fe(III) ON HTTA-IMBEDDED POLYURETHANE FOAM

The batch kinetics of Fe(III) adsorption on HTTA-loaded polyurethane (PU) foam have been investigated. The rate of controlling the adsorption is found to be intraparticle diffusion. The reaction rate of adsorption and desorption was also evaluated and found to increase and decrease with temperature, respectively. This indicates an endothermic adsorption behavior of Fe(III) on HTTA loaded PU foam. The activation energy of adsorption (80±10 kJ·mol−1) and of desorption (−45±±2 kJ· mol−1) indicates the chemical adsorption rather than physical adsorption. The isosteric heat of adsorption (δHads) was found to be −82.7±5.05 kJ·mol−1. This shows the formation of new chemical bonds among Fe(III)-HTTA-PU foam. The thermodynamic parameters of δG, δH and δS, and equilibrium constantKc have been calculated. These functions further support that the process of adsorption of Fe(III) on HTTA-loaded PU foam is endothermic and chemisorption, stabilized through thermodynamic functions.