Removal of lead ions by fixed bed of clinoptilolite – The effect of flow rate

The removal of lead ions from aqueous solutions by means of a fixed bed of natural zeolite clinoptilolite has been investigated. Isothermal column experiments were performed under a constant inlet concentration and bed depth, and different flow rates. The capacities of the breakthrough and exhaustion points do not change significantly with the increase of the flow rate, while the time needed to reach breakthrough is significantly shorter. To determine the kinetic constants, the equation by Yoon and Nelson was applied to the experimental results. The rate proportionality constant KYN increases and the time τ decreases with the increase of the lead solution flow. Based on these parameters the modelled breakthrough curves have been obtained, and they are in agreement with the corresponding experimental data. The parameters of the Yoon–Nelson model have been successfully used for scaling up the bed depth of the examined system, and a satisfactory agreement of experimental and predicted breakthrough curves has been obtained.