Regeneration and Reuse of Hydrotalcite-Like Anion Exchanger with High Selectivity to Phosphate Anion

摘要

Nobutoshi KIBA Regeneration methods of Mg-Al-Cl form hydrotalcite-like ion exchanger for selective adsorption of phosphate anion were investigated. It was possible to regenerate the reusable exchanger with high efficiency by the two-step regeneration method consisting of the treatment with a mixture of 0.25 mol centre dot kg~(-1) NaOH and 6.00 mol centre dot kg~(-1) NaCl solution at the first step, followed by that with 3.68 mol centre dot kg~(-1) MgCl_2 solution. The exchanger could be used for removal of phosphate ion with regeneration ratio of 50 percent even after nine times reuse. The regeneration ratio of the exchanger with granular form was examined in a flow system and found to be almost equal to 100 percent using the two-step regeneration method. The breakthrough capacity of the flow system was more than those of well-known zirconium ferrite type adsorbents even after six times runs.