Fig. 1. XRD patterns of samples at pH 7, 8, 9
a: pH 7; b: pH 8; c: pH 9

Fig. 1. XRD patterns of samples at pH 10, 11, 12
d: pH 10; e: pH 11; f: pH 12

Fig. 2. Samples of Chinese purple
(a): 160 ℃; (b): 180 ℃

Fig. 2. XRD patterns of samples at hydrothermal temperature of 120 and 140 ℃
a: 120 ℃; b: 140 ℃

Fig. 2. XRD patterns of samples at hydrothermal temperature of 160 and 180 ℃
c: 160 ℃; d: 180 ℃

Fig. 3. XRD patterns of samples with hydrothermal time of 12 and 24 hours
a: 12 h; b: 24 h; c: 48 h; d: 72 h