Thermal stability and E. coli adsorption of kaolinite nanotubes

Abstract

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 m2/g, 0.263 cm3/g, and 18.34 nm, respectively. KNTs were calcined from 300 °C to 800 °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 N2 adsorption–desorption analysis. The results indicate that the crystals of KNTs were damaged at 460 °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 °C, and then decreased gradually. The average pore size of calcined KNTs exhibited an opposite variation trend. When the KNTs were calcined at 500 °C, the SSA, pore volume, average pore size, and adsorption rate for E. coli were 91.74 m2/g, 0.320 cm3/g, 13.95 nm, and 54.3%, respectively. The morphology and tubular structure of KNTs were stable and slightly changed with calcination temperature.