Shuhua Han, Wanguo Hou, Chunguang Zhang, Dejun Sun, Xirong Huang and and Gouting Wang
Positively charged magnesium aluminium hydroxide sol has been prepared by coprecipitation. The structure and properties were studied using X-ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DTA), transmission election microscopy (TEM), FTIR and potentiometric titration (PT). The structure was shown to be hydrotalcite-like; the lattice constants a and c both increased with decreasing mole fraction of Al, x=[Al]/([Al]+[Mg]); the highest value of x was 0.332. Three weight loss peaks were detected by TG–DTA of the sol particles. IR spectroscopy showed that the position of the OH-stretching vibration peak shifted to high frequency and the peaks broadened with decreasing x. PT showed that the sol particles bore positive charges; the point of zero charge (pzc) and the amount of permanent positive charge both increased with increasing x.