Calcination on Ca-Mg-Al Hydrotalcite from Brine Water and Its Characterization

Abstract

The study of calcination treatment at 450°C on Ca-Mg-Al-hydrotalcite from brine water has been investigated. Characterization by XRD shows that Ca-Mg-Al hydrotalcite compound has found hydrotalcite phase and another phase such as Mg(OH) 2, Al(OH) 3 and CaCO 3. These results are confirmed by the presence of hydroxyl groups, M-O and M-OH groups (M is Mg, Ca and Al) at wavenumber region around 3464.35 cm -1, 447.50 cm -1 and 531.41 cm -1. The calcination effect on Ca-Mg-Al hydrotalcite compounds at 450ºC being led to changes in structure become an metal oxide such as MgO, CaO, Al 2 O 3, MgAl 2 O 4 and CaCO 3. These results are confirmed from decreasing on the absorption peak of M-OH group at wavenumbers region around 531.41 cm -1 and 786.99 cm -1 and widening of the absorption region at 500-900 cm -1. Consequently, the calcination treatment successfully increased the surface area of Ca-Mg-Al hydrotalcite compounds from 97.4 m 2 /g to 156.826 m 2 /g. Morphology of Ca-Mg-Al hydrotalcite changes the shape from a big to be small shape and the particle size distribution of 0-0.25 μm into 0-1 μm. Thermal analysis showed changes in the structure of hydrotalcite into oxide begins at a temperature of 265°C and started to become oxide completely after the temperature reaches 428°C.