Thermal analysis, both, thermogravimetric (TGA) and differential
thermal (DGA) analyses, of the purified samples was carried out by a
computer-controlled thermal analyzer (TGA 50, Shimadzu, Kyoto,
Japan). The non-isothermal analysis was conducted in the temperature
range of 20–1000 °C at 10 °C/min heating rate and 50 mL/min of air
flow rate. The data, presented in Fig. 2, shows that a total of 7% mass
loss took place in the studied temperature range. The main losses are
due to; ~3% moisture loss (around 100 °C), ~2% interlayer water loss
(around 200 °C) and removal of OH groups (dehydroxylation) on vermiculite
(above 500 °C, by ~2%). In like manner, two endothermic reaction
peaks just above 100 and 200 °C are discernible from DTA lines due
to moisture and interlayer water losses, respectively. Relying on XRF,
XRD, DTA and TGA data it can be concluded that the hand-picked vermiculite
sampleswerewell purified fromtheir associated carbonaceous
and other materials by the applied purification method.