Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg 2 Al-OH LDH formation and the successive anion-exchanges, ОН − → Cl − and Cl − → H 2 PO 4 − , were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg 2 Al-H 2 PO 4 LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.

Magnesium-aluminium-bismuth-layered double hydroxides (LDH) intercalated with carbonate were studied in respect of maximal rate of substitution of Al 3+ by Bi 3+ for the first time. LDH with the nominal compositions of Mg 3 Al 1x Bi x -CO 3 (x = 0 to 0.5) were prepared using both the conventional super saturation co-precipitation method and sol-gel processing via hydration of the mixed oxide powders in carbonate-containing solutions. The mixed oxides were obtained either by calcination of the LDH (prepared by co-precipitation) or by using a novel alkoxide-free sol-gel method. All the LDH products were characterised using the methods of X-ray diffraction, scanning electron microscopy and thermogravimetry. The observed values of the lattice parameters of LDH phases were compared with the calculated values. It has been found that, regardless of the preparation method used and the conditions (pH, temperature, time) applied, the maximum rate of substitution of aluminium by bismuth in LDH is about 20 mol.%.Graphical abstract A schematic representation of LDH structure of a 3R polytype [4,5] where the lattice parameter c and the basal spacing d relate to each other as c = 3d.

et al., Cast iron corrosion protection with chemically modified Mg-Al layered double hydroxides synthesized using a novel approach, Surface & Coatings Technology,

Layered double hydroxides having different cationic (Mg 2+ , Co 2+ , Al 3+) composition were successfully synthesized by the low supersaturation method. The samples were thermally decomposed and reconstructed using water and nitrate media at different temperatures. X-ray powder diffraction analysis, X-ray fluorescence analysis, thermogravimetry and BET/BJH methods were used to investigate the differences between the directly obtained layered materials and those after the reconstruction process.

Brushite mineral shows potential in wood reinforcement and development of hybrid calcium phosphate-based wood composites that could be particularly attractive in the construction sector as an environmentally friendly building material.