Hydrothermal synthesis of Mg–Al layered double hydroxides (LDHs) from natural brucite and Al(OH)3

By using natural brucite and Al(OH)3 as the starting materials, the Mg–Al layered double hydroxides (Mg–Al–CO3-LDHs) have been successfully synthesized via a simple hydrothermal strategy. The effect of hydrothermal synthesis temperature and reaction time on the crystal structure, grains size and Mg/Al molar ratios of Mg–Al–CO3-LDHs were investigated. The results showed that the cell parameters and Mg/Al molar ratios of the Mg–Al–CO3-LDHs increase when the hydrothermal reaction temperature increases from 140 °C to 180 °C. The size of crystal grain parallel to the direction of the layer D1 1 0 is roughly constant, while the size of crystal grain in the vertical direction of the layer D0 0 3 increases and D1 1 0/D0 0 3 decreases with the increment of hydrothermal reaction temperature.