Thermal stability and E. coli adsorption of kaolinite nanotubes

Using a solvothermal method, natural kaolin was used to prepare kaolinite nanotubes (KNTs) with a specific surface area (SSA), pore volume, and average pore size of 57.41 m(2)/g, 0.263 cm(3)/g, and 18.34 nm, respectively. KNTs were calcined from 300 degrees C to 800 degrees C and then characterized by X-ray powder diffraction, Fourier-transform infrared spectroscopy, differential scanning calorimetry-thermogravimetric analysis, field-emission scanning electron microscopy, transmission electron microscopy, and N-2 adsorption-desorption analysis. The results indicate that the crystals of KNTs were damaged at 460 degrees C due to dehydroxylation. The SSA, pore volume, and adsorption rate for Escherichia coli of calcined KNTs first increased gradually, reached the maximum values at 500 degrees C, and then decreased gradually. The average pore size of calcined KNTs exhibited an opposite variation trend. When the KNTs were calcined at 500 degrees C, the SSA, pore volume, average pore size, and adsorption rate for E. coli were 91.74 m(2)/g, 0.320 cm(3)/g, 13.95 nm, and 54.3%, respectively. The morphology and tubular structure of KNTs were stable and slightly changed with calcination temperature.