Synthesis, Characterization, and Ion Exchange Properties of Hydrotalcite Mg₆Al₂(OH)₁₆(A)_x(A‘)_2-x·4H₂O (A, A‘ = Cl^-, Br^-, I^-, and NO₃^-, 2 ≥ x ≥ 0) Derivatives

A series of monovalent anion-containing hydrotalcites (HTCs) with the general formula Mg 6 Al 2 (OH) 16 (A) x (A‘) 2 - x ·4H 2 O (A, A‘ = Cl -, Br -, I -, and NO 3 -, 2 ≥ x ≥ 0) have been studied. Samples were synthesized by three different methods: ion exchange (IE), hydrothermal (HT), and recrystallization based on “memory effect” (ME). The physical, structural, and chemical characteristics and properties of the HTCs have been studied as a function of the synthetic methods and anions used. All three synthetic methods produced HTCs of good crystallinity and uniform particle size. When a second (A‘) or all four (Cl -, Br -, I -, NO 3 - ) anions were present together with an A-HTC in an aqueous medium, the order of ion exchange preference was Br - > Cl - > NO 3 - > I - . When using one-pot synthetic methods (HT, ME), the same order of anion incorporation preference, Br - > Cl - > NO 3 - > I -, was observed.