Layered Double Hydroxides with the Composition Mn/Al-SO4-A (A = Li, Na, K; Mn:Al ca. 1:1) as Cation Exchangers

Hydrated Mn/Al-SO4-A (A = Li, Na or K) layered double hydroxides with M2+:M3+ molar ratio close to 1:1 were synthesized by co-precipitation with increasing pH. All phases presented solvated alkali metals and sulfate as intercalated species. In the exchange reactions, when sulfate solutions of alkali metals were used, sodium could be partially replaced by potassium, and the same was true for the potassium phase, where potassium could be partially replaced by Na and Li, without removing the intercalated sulfate anions. This class of compounds, considered to be anion exchanger, can also exchange cations, which opens new perspectives for applications.