From platy kaolinite to aluminosilicate nanoroll via one-step delamination of kaolinite: Effect of the temperature of intercalation

Aluminosilicate nanorolls were prepared using a method of one-step delamination of kaolinite. In this method, cetyltrimethylammonium chloride (CTMACl) was intercalated into the interlayer space of methoxy-modified kaolinite, which resulted in the delamination and rolling of kaolinite layers. The reaction conditions of CTMACl intercalation significantly influenced the formation of nanorolls, as shown by characterizations using X-ray diffraction, electron microscopy, infrared spectroscopy, thermal analysis, and nitrogen adsorption. Overall, increasing the CTMACl-intercalation temperature helps to promote the transformation from platy kaolinite to nanorolls. The initial kaolinite particles were mostly transformed to nanorolls in the product prepared at 80 °C, whereas considerable kaolinite particles remained untransformed in the product prepared at 30 °C. At 80 °C, the obtained specific surface area (SSA) and the porous volume (Vpor) values of the nanoroll product are nearly twice the values obtained at 30 °C and the tubular structure exhibits higher thermal persistence. The tubular morphology and the porosity of these nanorolls obtained at 80 °C, were largely retained after calcination at 600–800 °C. However, a calcination at 900 °C led to an obvious distortion of the nanorolls and a decrease in SSA and Vpor values. The observed structural changes of the nanorolls under calcination generally resembled that of natural halloysite but occurred at lower temperatures because the prepared nanorolls were of lower structural order with thinner tube walls.