Application of the adsorbent CR-100 for Ammonium Removal: Thermodynamic and Kinetic Studies

Abstract

Groundwater with increased ammonia concentration is a constant concern regarding the preparation of drinking water. The affinity of ammonia to be adsorbed on the surface of different solid materials significantly influences the selection of its removal process and has been the motivation for this investigation. Crystal-Right™ (CR-100) was used for the removal of ammonia from aqueous solution in batch adsorption procedure. The kinetics of adsorption followed the pseudo-second-order model. The Elovich model suggested that chemisorption rate decreased with the temperature increase. The liquid film diffusion and intra-particle diffusion models revealed that heterogeneous adsorbent surface energy had a particularly pronounced impact on the overall mass transfer rate. The Arrhenius and Eyring's equations suggested spontaneous and endothermic nature of complex adsorption/ion exchange removal process. The isosteric heat of adsorption revealed that with the increase in surface loading lateral interactions between the adsorbed molecules occurred.