Modification of Block-Porous Systems with Sorption-Active Materials

We have prepared block-porous systems modified with sorption-active materials and differing in major component (AD1 aluminum or Kh20N80 steel) and porosity (0.6 or 0.75). Before applying a layer of a sorption-active material, an adsorption layer was produced on the surface of the block-porous material via chemical oxidation in the case of aluminum and thermal oxidation in the case of steel. BAU activated carbon and Polysorb-1 were used as modifiers and polymethylsiloxane was used as a binding component. Examination of the surface morphology of the systems showed that particles of the sorption-active materials had the most uniform distribution in the case of Polysorb-1 on the steel surface. To compare sorption characteristics of the sorption systems for preconcentration of volatile organic compounds, we evaluated the degree of recovery in preconcentration and desorption using a standard gas mixture containing 0.7 mg/L of hexane. The degrees of recovery ensured by the systems studied are comparable to those in the case of powder sorbents and depend on the weight of the sorption-active material applied. The highest degree of recovery (61%) was reached with the sorption systems having Polysorb-1 and polymethylsiloxane on their surface because both substances exhibit sorption activity for volatile organic compounds. Using the sorption systems five times was shown to cause no decrease in the degree of recovery upon sorption or desorption, suggesting that they can be successfully used repeatedly.