Removal of NH₄⁺ Ion from NH₄Cl Solution Using Clinoptilolite: A Dynamic Study Using a Continuous Packed-Bed Column in Up-Flow Mode

An investigation, in the form of dynamic experiments, was designed to investigate equilibrium and kinetic information for the ammonium ion-exchange of clinoptilolite. The process consisted of a packed-bed column operated in up-flow mode. A number of experiments were carried out at laboratory scale. The total ionic strength was kept constant in all runs, and made to resemble the ionic environment of the effluent from the landfill assisted froth flotation (LLAFF) process, in order to validate the feasibility of using clinoptilolite to remove NH₄⁺ ion from that wastewater. Breakthrough curves and reduced data of the Thomas equation were constructed from a range of experimental tests in order to determine maximum exchange capacity (q) and design reaction constant (k). Feed rate and packing techniques have a major effect on the dynamic condition inside the column. The influence of multi-component ions on the NH⁺₄ ion-exchange performance of clinoptilolite was also studied in order to determine the negative effect of competing cations, i.e., K⁺, Ca2⁺, and Na⁺. The results of the study show that the column system gives an acceptable response to variable influent NH₄⁺ loads. Desorption phenomena were also investigated when the influent was shifted to very low concentrations of NH⁺₄ loads. Overall, a fixed-bed system of clinoptilolite shows high potential to remove Ma ion from the effluent of the LLAFF process.