Removal of Toxic Anions in Aqueous Solution by Anion Exchanger Synthesized from Steelmaking Slag

抄録

Layered double hydroxides (LDHs) were synthesized by a co-precipitation method using steelmaking slag as a raw material. The adsorption of toxic anions including As(III), B, Cr(VI) and Se(IV) in aqueous solution was investigated in order to clarify the removal property of anionic species by the obtained products. The order of removal for four anionic species with the steelmaking slag-derived LDHs (slag-LDHs) is as follows; Se(IV) > Cr(VI) > As(III) > B in the low equilibrium concentration below 10 mg/dm³. The order implies that the valency of anionic species is mainly related to the anion adsorption order in the low concentration, that is, an anion with larger valency is easily captured in the LDHs structure. On the other hand, the saturated adsorption amount is considered to be the following order; As(III) > Se(IV) > Cr(VI) > B as a standard of mass. No remarkable difference in the crystalline materials is found before and after the As(III) adsorption operation. It is found that the steelmaking slag-derived LDHs are applicable as an anion removal agent for the dilute aqueous solution containing anionic species.