Preparation and Characterization of Nanosized Hematite Colloids Using Green Vitriol as Ferrum Source
Figure 4
TG-DTA spectra of the as-prepared samples at pH 4, 5, 6, and 7, respectively. The face of the α-Fe2O3 crystalline was lost gradually, in the whole of the temperature range, but the loss of hydroxyl groups in the α-FeOOH crystalline molecular occurred rapidly at 270°C, which was confirmed by the sharp peaks in the DTA curves of the samples with pH 6 and 7, especially with pH 7, which prove the presences of α-FeOOH in the samples from the reaction conditions of pH 6 and 7.
