無機層状イオン交換体ハイドロタルサイト化合物を用いたヒ素・セレン除去

抄録

It is well known that a hydrotalcite-like compound is a layer structure inorganic ion exchanger and has a high selectivity for certain anions. The authors clarified that the synthetic Mg-A-Cl form hydrotalcite (HT) has a high selectivity and a large adsorbing capacity for phosphate ions. It is estimated that HT has a high selectivity for anions, such as arsenate, arsenite, selenate and selenite ions, that have the same size and properties as phosphate ions. Therefore, we examined the adsorption capacities of HT to AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- in order to remove these anions using HT from the waste water. The obtained results were as follows. HT rapidly adsorbed AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- at the anion concentrations of 0.2 to 100 mg·l^-1. The selectivity of AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- on the HT is very high. The removal mechanism of HT for AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- was ion exchange for Cl^-. Furthermore, HT had a high ion exchange capacity for AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- under the condition of coexistence with other anions. Moreover, the concentrations of AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- in all treated water samples were below 0.1 mg·l^-1, which is the waste water quality standard of As and Se. These results showed that HT is an effective adsorbent for the removal of AsO₄^3-, AsO₃^3-, SeO₄^2- and SeO₃^2- in the waste water.