ANION-EXCHANGE ABILITY ON ARSENATE AND ARSENITE ANIONS OF LAYERED DOUBLE HYDROXIDE CONSISTING OF NICKEL AND ALUMINUM CATIONS

Abstract

In this study, the selectivity for arsenate or arsenite of layered double hydroxide (LDH) consisting of Ni and Al with chloride anions as anion-exchangeable anion species was investigated using LDH with different Ni/Al molar ratios. As a result, LDH with a Ni/Al molar ratio of 2 was highly selective for arsenate, while LDH with a Ni/Al molar ratio of 4 was highly selective for arsenite. From various experimental analyses, arsenate was incorporated into the interlayer space of LDH with a Ni/Al molar ratio of 2 by the anion exchange reaction from chloride to arsenate anions. In the case of LDH with a Ni/Al molar ratio of 4, arsenite anions were incorporated by the anion-exchange reaction, and then chemical bonds were formed with the metal hydroxide layer.