Two-Phase Structure of Fluorinated Powdered Silica Resulting from Deep Processing of Rice Wastes

Abstract

In this investigation the structure of «green» silica maid with rice husk has been studied by methods of physicochemical analysis. By method of X-ray diffraction it has been found that the samples of «green» silica powders are completely amorphous, and the observed amorphous halo consists of two components. By method of scanning electron microscopy it has been revealed that nano-particles of «green» SiO2 can form agglomerates and microstructures with dimensions from 0,1 to 500 microns, containing numerous pores, which presence has been confirmed by sorption measurements. By method of mass spectrometry with inductively coupled plasma has been found the presence of aluminum, titanium and nickel mechanical impurities in the «green» SiO2 powders. By method of X-ray photoelectron spectroscopy significant amount of fluorine atoms in «green» silica (up to 5% (at.)) has been revealed, which could be introduced in SiO2 in the process of its preparation. In such a case, it was found that fluorine interacts with «green» silica by means of two mechanisms, leading to appearance of two phases within fluorinated powders of «green» SiO2.