The adsorption of EDTA-chelated copper ion in aqueous solution by an activated carbon adsorption column

A series of column adsorption experiments on the adsorption of EDTA-chelated copper by activated carbon were conducted to obtain more applicable design data. The efficiency of utilization of activated carbon bed improves with increasing empty bed contact time (EBCT). But the absorption capacity of activated carbon usually increases with decreasing EBCT value. Two different adsorption models, the Bed-Depth-Service-Time (BDST) model and Homogeneous Surface Diffusion Model (HSDM), are used to simulate the experimental data. The adsorption behavior of Cu-EDTA in an activated column can be described by the BDST model, but the fitted rate constant of adsorption (k) decreases with increasing EBCT, thus, it is necessary to modify the BDST model to further estimate the exhaust time of activated carbon under various conditions. The fitted results of the HSDM model indicate higher deviations to the experimental results, possibly because the adsorption rate is mainly determined by the surface reaction step.