## 3 Results
### XRD Analysis of Modified Mt  
The XRD patterns of the Mt and modified Mt are shown in Figure 3. The Mt displayed a reflection at 7.34\({}^{\circ}\), corresponding to a basal spacing of 1.20 nm. This value was in accordance with similar hydrated clays reported by other papers [33; 34]. The reflection occurred at 5.97\({}^{\circ}\) for the H-Mt, corresponding to a basal spacing of 1.47 nm, which could be attributed to the fact that the hydrochloric acid could remove certain impurities on the Mt surface, open the platelet edges, and consequently increase the surface area [35]. The diffraction peak of P-Mt corresponds to an interlayer spacing of 2.26 nm, indicating that the TTPC surfactants had intercalated and expanded the basal spacing, and a pseudotrimolecular layer orientation of the surfactants was obtained [36]. For the Si-Mt, the reflection peak position shifted slightly to a lower 20 value, indicating that the \(\gamma\)-MPS had a small effect on the interlayer structure, due to the low level of intercalation. According to the literature [37], the \(\gamma\)-MPS molecules were mainly grafted onto the exterior surfaces and/or the broken edges of the clay. This result also indicated that \(\gamma\)-MPS was not the appropriate molecule for the intercalation to effectively expand the interlayer spacing.  
Compared with the H-Mt, the sharp peak (d value = 1.91 nm) of the H-P-Mt clearly showed a bilayer arrangement of TTPC molecules [38]. However, the basal spacing of the H-P-Mt was 0.35 nm smaller than that of the P-Mt, indicating that the amount of intercalated surfactants could be decreased, due to the effective removal of Na\({}^{+}\). When the H-Mt was further modified by \(\gamma\)-MPS, no significant changes were observed in the XRD peak position, due to the silane molecules being mainly grafted onto the exterior surface and/or at the broken edges.  
The observed small decrease in the basal spacing for the H-P-Mt, after the \(\gamma\)-MPS grafting, decreased from 1.91 nm to 1.82 nm, indicating that the intercalated surfactants were washed out by the hydroalcoholic solution in the process of silylation. However, the basal spacing of the H-P-Si-Mt was bigger than that of the P-Si-Mt, which suggested that a small amount of \(\gamma\)-MPS molecules had been grafted into the interlayer spacing of H-P-Mt. Almost no \(\gamma\)-MPS was grafted into the P-Mt, due to the absence of acid activation pretreatment to improve the amount of hydroxyl groups. For the H-Si-P-Mt, the broadeningof the peak was characteristic of a more disordered structure, and two families of modified Mt, with different interlayer spacing (1.75 and 1.46 nm), were formed, indicating the successful intercalation of the surfactants into the H-Si-Mt. The reason was because of the H-Si-Mt being filled with silane molecules, which partly hindered the surfactants ion exchange reaction, resulting in uneven interlayer distances. Compared with the H-Si-P-Mt, the Si-P-Mt presented one basal reflection, and the value of interlayer spacing was similar to the H-Si-P-Mt. It can be concluded that there were almost no silane molecules presented in the interlayer spacing of Si-Mt, and the block effect for the TTPC intercalation was lower than that of H-Si-Mt.