Optimization of the Choice of Technological Methods for Nanomodification of Natural Aluminosilicates through the Parameters of the Element-Oxygen Chemical Bond

Abstract

The paper shows the possibility of using such quantitative characteristics of the element-oxygen chemical bond as the covalent character, metallic character and ionic character in substances to select a set of technological methods and develop a technology for nanomodification of natural bentonite aluminosilicates. The research results showed that thermal activation of bentonite at 200, 300, 380 and 400 °C with different modes of isothermal exposure (15, 30, 60, 120 minutes) does not significantly affect the efficiency of its modification with silicon (SS) and aluminum (AS) oxide nanoparticles, estimated by the increment of the compressive strength and the adsorption index for methylene blue. Obtaining a 46 % aqueous suspension of bentonite and modifying it with silicon and aluminum oxide nanoparticles followed by ultrasonic treatment after standing decreases the particle size by more than 4 times, which is a promising technological solution for improving the performance properties of ceramics, molding mixtures, adsorbents and other materials based on bentonite from various deposits.

Transformation of the structure and adsorption properties of bentonite during physical and chemical treatment

“…Stabilized hydrosols of aluminum oxide (AS) were used as modifiers -an aqueous dispersion of nanocrystalline boehmite with the general formula AlOOH and a crystallite size of 3.5-4 nm, pH = 4, and silicon oxide (SS) with an amorphous structure and a particle size of 6.0-10.5 nm, pH = 10 [6][7][8].…”

“…In accordance with formula 1, the efficiency of the UT is 0.8. With an increase in the intensity of processing described in work [7], the efficiency increases to 30.…”

“…The most common methods for transforming the structure and properties of smectites in bentonite in the scientific literature include acid treatment [3,[9][10][11] and activation with sodium carbonate in suspension [12]. In addition to these methods, it was shown [6][7][8] that the modification of bentonite with nanodispersed hydrosols of aluminum and silicon oxides (3.5-10.5 nm) increases the adsorption index for methylene blue (MB) by 20-25%, respectively, the swelling capacity of the suspension and the ultimate strength for compression. In order to achieve higher adsorption properties of natural bentonite raw materials, in this work, we investigated the possibility of effectively combining nanomodification with physical (microwave and ultrasonic treatment) and chemical effects -acid treatment and activation with sodium salt.…”