Modelling of phosphorus removal by ion-exchange resin (Purolite FerrIX A33E) in fixed-bed column experiments

摘要

Phosphorus removal is important as it causes eutrophication that in turn has a harmful effect on fish and other aquatic life, resulting in a reduction in biodiversity as well as unfavourable human environmental health. In this study, phosphorus removal from aqueous solutions was studied using an ion-exchange resin (Purolite FerrIX A33E) in fixed-bed column experiments. The effects of adsorbent bed height (3-19 cm) on the breakthrough characteristics of the adsorption system were studied. An increase in bed height (3-19 cm) increased adsorption capacity but the breakthrough time was shorter. As the bed height increased, the detention time increased and the phosphate was in contact with the purolite ion-exchange resin for a longer time, resulting in more efficient removal of phosphate. The shape of breakthrough curve was steeper for a shorter bed height. A mathematical model (advection-dispersion equation) was solved numerically to predict the dynamic behaviour of the columns. Finally, sensitivity analysis results apparently revealed that the dynamic adsorption behaviours of phosphate in Purolite FerrIX A33E were mainly controlled by the external mass transfer rather than the axial dispersion and the intra-particle diffusion.