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The production of propylene by dehydration of 2-propanol at solid-vapor interfaces, as an example of the acidcatalyzed surface reaction, was explored by using sulfonated polyacrylonitrile-derived activated carbon fibers (PAN-ACFs). To prepare these catalysts, the PAN-ACFs obtained by onestep carbonation-activation were modified with a surface coverage of high acidity. The surface of PAN-ACFs was sulfurated with sulfur vapors at high temperatures followed by oxidation, to yield the corresponding sulfonates. The chemical analysis showed that the carbon surface layer contains from 1.28 to 6.10 mmol$\mathrm{g}^{-1}$ of sulfur, including the contribution of sulfonic $(\mathrm{S}\mathrm{O}{}_{3}\mathrm{H})$ groups. In addition to sulfonic groups, the obtained catalysts contain carboxyl, lactone, and phenolic groups, which are formed as a result of oxidation treatment. In order to understand the changes in surface chemistry and the results of sulfuration and oxidation, the sulfonated PAN-ACFs were characterized by a variety of techniques including TPD MS, TGA, SEM, and FTIR ATR. During a typical temperature mode screening at catalyst testing, it was found that the sulfonated PAN-ACFs prepared by treatment with sulfur vapor at low temperature, at $400\circ \mathrm{c}$ and $500\circ \mathrm{c}$, are very efficient at dehydrating 2-propanol. A weighed mass of 100 mg of each of these catalysts was operated at 165-175°C in 12 hours, and the catalysts were characterized by high conversion of 2-propanol and high selectivity to propylene, with a propylene yield of about 100%. Furthermore, the solid acid catalysts have high stability and strong acidity and can be reused with no significant loss in the activity after the third cycle in the subsequent 20 cycles. The preparation of solid acid catalysts from PAN-ACFs affords a novel strategy for producing propylene through alternative green and sustainable technologies.

Hydrogels loaded with silver nanoparticles are promising materials for biomedical antibacterial application. This work was focused on the synthesis of hydrogel–silver nanocomposites based on Dextran-graft-Polyacrylamide copolymers in non-ionic and anionic form. A photochemical synthesis of colloidal silver particles through Ag seed-mediated growth under the UV solar radiation was carried out. All nanocomposites have revealed an absorption peaks at 420 nm corresponding to silver nanoparticles (AgNPs) Plasmon absorbance. However, the character of the absorption bands was dependent on the condition of AgNPs synthesis and chemical nature of polymer hydrogel. The obtained nanocomposites demonstrated high antibacterial efficiency against Escherichia coli and Staphylococcus aureus.

The thermal resistivity method, which is a convenient and sensitive to electrical resistance changes, was proposed for control of chemical modification of nanoporous activated carbon fibers (NACF) with hydrofluorocarbons (HFC). The surface state changes could be monitored by measuring Ohmic resistance during heating, physisorption, and chemical reaction between the activated carbon material and HFC. Thus, we found a correlation between the fluorine content in the resulted carbon material and electrical resistance, measured from the room temperature to 900 °C. It was shown that in this way the temperature of the beginning of a chemical reaction and the temperature of the most effective chemical modification could be determined. The thermal grafting of fluororganic groups onto NACF is assumed to be the reason for the changed electrical resistivity of the initial NACF.

Activated carbon fibers (ACFs) made from polyacrylonitrile and viscose were treated with the sulfur vapor at the temperatures of 500–800 °C in an argon flow. Obtained materials were oxidized by 30% H 2 O 2 water solution in order to convert S-containing surface moieties into SO 3 H-groups. The samples were studied using Boehm titration, thermogravimetric analysis and temperature-programmed desorption with a mass spectrometric registration of gaseous desorption products. According to obtained data, the surface layer of synthesized samples contains grafted SO 3 H-groups and different functional groups formed at the carbon oxidation. The decomposition of SO 3 H-groups occurs in the temperature range of 75–590 °C. Two peak maxima at 200±30 °C and 300±30 °C were registered on all SO 2 desorption profiles. These maxima are assigned to two forms of surface SO 3 H groups having a different chemical environment. Testing of the catalytic activity shows that SO 3 H-functionalized carbon fibers are high active in the model reaction of propan-2-ol dehydration. The total conversion of propan-2-ol to propene is observed at 145–220 °C. The lowest temperature of total conversion was registered for the ACFs prepared from polyacrylonitrile being treated with the sulfur vapor at 500 °C. All SO 3 H-functionalized samples maintain their activity after repeated use.