CHEMOSORPTION COMPOSITIONS BASED ON PHLOGOPITE FOR LOW-TEMPERATURE AIR PURIFICATION FROM SULFUR DIOXIDE

It is known that a large amount of sulfur dioxide is released into the atmosphere during the production of sulfuric acid, the combustion of metal sulfides at non-ferrous metallurgy enterprises, during the burning of coal containing sulfur, at thermal power plants, and in many other industries. In the air of industrial companies, its concentrations often significantly exceed the maximum allowable concentration (10 mg/m3 for the working area), despite the use of equipment for the sanitary treatment of exhaust gases. Therefore, there is a need to develop highly effective personal protection equipment of workers’ respiratory organs against sulfur dioxide in the form of respirators or gas masks. For their production, it is necessary to create cheap, affordable and reliable sorbents. A large number of methods for cleaning air and exhaust gases from sulfur dioxide are known. Among them, a special place is occupied by methods based on the use of nitrogen-containing bases, for example, urea, mono-, di- and triethanolamines, hydrazine, hydroxylamine, and hexamethylene tetramine (HMTA). Therefore, the use of aqueous solutions of nitrogen-containing bases as active components of sulfur dioxide chemosorbents is quite promising. However, their use in respiratory personal protection equipment, which would work according to the principle of using the absorption process, is quite difficult. Therefore, we made an attempt to impregnate a porous medium, as natural flagopite, with aqueous solutions of HMTA and NaOH. It was determined using X-ray phase analysis, that natural phlogopite, in addition to the main phlogopite phase, contains various impurities, such as diopside, vermiculite, clinochlore, and cordierite. To establish the type of adsorption, the adsorption and desorption of sulfur dioxide by natural phlogopite was studied. It has been proven that sulfur dioxide is weakly bound to the surface of natural phlogopite, that is, its physical adsorption mainly occurs. The perspective of using natural and chemically modified phlogopite for chemisorption neutralization of sulfur dioxide, provided its low concentration (150 mg/m3) in the air, is shown. It was established that monocomponent compositions based on NaOH and HMTA fixed on natural phlogopite absorb sulfur dioxide, but under the condition of their combined action at a certain ratio of components, a synergistic effect is observed, which is manifested in an increase in the time of the protective effect and adsorption capacity of the compositions.