Modification of block-porous systems with sorption-active materials

The possibility of getting block-porous systems modified with sorption-active materials for the determination of volatile organic compounds was considered. The prepared samples of the block-porous systems differ in the base material (AD1 aluminum and X20N80 steel) and porosity (0.6 and 0.75). Before applying a layer of sorption-active material on the surface of the block sample, an adsorption layer was formed by chemical (for aluminum) oxidation and thermal (for steel) oxidation. Activated carbon BAU, Polysorb-1 and polymethylsiloxane as a binding agent were used as modifiers. When studying the surface morphology, it was found that the most uniform distribution of particles of the sorption-active material is observed for Polysorb-1 on the steel surface. To compare the sorption characteristics of the resulting sorption systems, the degree of recovery during concentration and desorption using a standard gas mixture of hexane with a concentration of 0.7 mg/liter was assessed. The values of the recovery degree for the studied samples are comparable to those of powdered sorbents and differ depending on the amount of the applied active layer. It is shown that the highest recovery degree (61%) is achieved for samples of sorption systems with Polysorb-1 and polymethylsiloxane applied to the surface, since both substances exhibit sorption activity towards volatile organic compounds. Moreover, it is shown that when samples of sorption systems were used even five times, there was no decrease in the degree of extraction during sorption and desorption, which indicates the effectiveness of their repeated use.