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

Abstract

The paper presents the results of studies of the effect of electromagnetic, ultrasonic and acid treatments on the structure and the adsorption index of alkaline-earth bentonite modified with nanoparticles of silicon oxide and aluminum. Studies have shown that electromagnetic, ultrasonic and acid treatments contribute to an increase in the adsorption capacity of bentonite modified with nanoparticles of silicon oxide by 5, 10, and 25%, respectively. Modification of bentonite with stabilized nanodispersed hydrosols of amorphous silicon oxide (6-10.5 nm) and crystalline boehmite (3.5-4 nm) of 0.1-0.5 wt. % with subsequent ultrasonic and microwave treatments allows to increase its adsorption index for methylene blue and the cation exchange capacity up to 40%. And during the combining with preliminary activation in suspension with sodium carbonate it allows to increase up to 80%. The increase in the adsorption properties of bentonite is due to a double increase in the homogeneity of the structure, dispersion and specific surface area of aluminosilicate particles and transformations of the phase composition. As a result, through the use of advances in the field of nanotechnology, a combining of physical and chemical effects, the technology of modifying natural aluminosilicates based on bentonite has been improved, which makes it possible to significantly increase the adsorption characteristics of materials based on it.