Equilibrium and dynamic adsorption of heavy metals onto spent coffee ground (SCG) were studied.The equilibrium adsorption of\nCd2+, Cu2+, and Pb2+ in a batch system was modeled by an ion-exchange model (IEM) based on an ion-exchange of heavy metals\nwith calcium and protons bonded to active sites on SCG surface. The maximum amount of adsorbed metal ions obtained using\nthe IEM was 0.12, 0.21, and 0.32mmol/g of Cd2+, Cu2+, and Pb2+, respectively. Regeneration of SCG was evaluated using citric\nacid, calcium chloride, and nitric acid. The observed trend of desorption efficiency through four adsorption-desorption cycles\nwas HNO3 > CaCl2 > C6H8O7. The effect of process variables such as flow rate and bed height during the dynamic adsorption\nwas evaluated. Moreover, the applicability of a mass transfer model based on external mass transfer resistance, axial dispersion,\nand ion-exchange is othermwas evaluated, and the results were in good agreement with the experimental data for the adsorption in\nSCG packed column.The sensitivity analysis of the model parameters showed that axial dispersion coefficient is the most significant\nparameter in the dynamic simulation. The results obtained showed the potential of SCG as a low-cost material for waste water metal\nremoval in continuous systems.
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