ANION EXCHANGE REACTIONS OF LAYERED DOUBLE HYDROXIDES (LDHs) AND LAYERED HYDROXY SALTS (LHSs): QUANTIFICATION OF ION EXCHANGE Abstract Anion exchange reactions of a number of layered double hydroxides with inorganic anions

Anion exchange reactions of a number of layered double hydroxides with inorganic anions were investigated. The five LDH systems used in this study were Mg-Al, Ni-Al, Co-Al, Zn-Al and Zn-Cr. Ni-Zn hydroxynitrate and Ni-Zn hydroxyacetate were the LHSs used in this work. In general, all the LDHs and nickel zinc hydroxysalts exhibited higher extent of exchange towards chloride ions. The extent of exchange in the monovalent anion exchange reactions follows the order Cl > Br > I ~ CH3COO . Obtaining 100% pure single anion intercalated LDHs by anion exchange method in a single step was difficult since in most of the cases, a very small amount of precursor anion was present in the solid samples after anion exchange. Ni-Zn LHSs had a slightly different anion exchange behaviour compared to LDHs.