Keywords: adsorption, breakthrough curve, modelling, dynamic experiments, step tests, pulse tests, activated carbon adsorption columns, copper ion recovery, copper ions, aqueous effluent, industrial effluents
The use of step and pulse tests to design activated carbon adsorption columns for recovery of copper ions from aqueous industrial effluents
Dynamic experiments were carried out on the adsorption of copper ions in a laboratory packed bed of activated carbon. Both pulse and step change inputs were used. Measurements were reproducible and replicate measurements furnished nearly identical parameters for a conventional heterogeneous model of the activated carbon bed, assuming a Langmuir adsorption isotherm. Bed depth had little effect on parameters. Hydraulic loading affected dispersion and the volumetric mass transfer coefficient but, unexpectedly, also changed the effective diffusivity. This apparently comes from incorporation of errors due to measurement noise and model approximations in the parameter. Parameter differences between pulse and step inputs likely arise from concentration differences. These affected the Langmuir adsorption isotherm constants and diffusivity, as expected from their concentration dependency. Step change and pulse simulations support the reliability of the novel design and the procedures proposed even though comparison of the model parameters extracted with literature values was inconclusive.