The interaction between organics and metal complexes in adsorption columns

Abstract

The literature on the design of columns used for the adsorption of organics from waste-water is quite substantial. Many principles associated with the design of such columns can be applied in the design of adsorption columns for metal complexes. This study reports on the interaction between organics and dissolved metals in a column using activated carbon or ion-exchange resin as an absorbent. It will be shown here that many long-chain organics do not affect the equilibrium of adsorption of metal complexes, but have a profound effect on the kinetics of uptake of metal complexes. The kinetics of adsorption were described by a dual-rate kinetic model which was developed for a multi-component adsorption system. Furthermore, the intraparticle diffusivity which was associated with pore-blocking, decreased with an increase in the molecular mass of the organic species. In the case of the simultaneous adsorption between a metal cyanide and organic species, the Freundlich-type multi-component isotherm was found to be adequate to describe the equilibrium adsorption. A parametric sensitivity analysis was performed on the adsorption system to demonstrate the model flexibility for different operating conditions. Backmixing in the column seemed to be of minor importance.