Layered double hydroxides with the composition [Mn6Al3(OH)18][(HPO42-)2A+]•yH2O (A+ = Li, Na or K) obtained by topotactic exchange reactions

Layered double hydroxides (LDH) with the chemical composition [Mn6Al3(OH)(18)][(HPO42-)(2)A(+)]center dot yH(2)O (A(+)= Li, Na or K) were synthesized for the first time and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Inductively coupled plasma optical emission spectrometry (ICP-OES) and Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS). The precursor materials [Mn2Al(OH)(6)]Cl center dot yH(2)O (basal distance of 7.76 angstrom), [Mn2Al(OH)(6)]NO3 center dot yH(2)O (basal distance of 8.88 A) or [Mn6Al3(OH)(18)][(SO42-)(2)A(+)]center dot yH(2)O (A(+) = Li, Na or K; basal distance close to 11 angstrom) were synthesized by coprecipitation with increasing pH. In the topotactic exchange reactions, the precursor having chloride and nitrate incorporated alkali metal cations and hydrogen phosphate while the materials intercalated with sulfate and alkali metal cations showed the ability to exchange anions and cations, opening new opportunities for potential applications where these species need to be removed and reused.