Physicochemical Properties of the Solid Component of Welding Aerosol. I. Phase Composition

Acid-modified clinoptilolite as a support for palladium–copper complexes catalyzing carbon monoxide oxidation with air oxygen

“…A further appreciable decrease in pH st is observed only for 3H-CLI at approximately the same ΔpH s value. Taking into consideration the results of our earlier works [4, 24, 31, 32, 35, 36], this decrease in pH of the aqueous suspension may be one of factors promoting formation of the surface palladium–copper composition optimal for realizing catalytic CO oxidation.…”

“…However, it has been found by us [31, 32] that a composition and catalytic performance of surface palladium–copper complexes in some redox processes, namely, carbon monoxide and phosphine oxidation, significantly depend on a thermodynamic activity of water adsorbed on them ( = P/P S ). This parameter was determined from isotherms of water vapor adsorption and proved to be necessary for both obtaining catalysts of optimal composition and their applying in respiratory and environment protection.…”

“…Our choice of nitric acid as a modifying agent is caused by the following circumstance. Adsorbability of ions in the case of clinoptilolite decreases in the order Cl − ≫SO 4 2− >NO 3 − [34], so, some amounts of chloride and sulfate ions can remain after their desorption by water and, consequently, these residual chloride and sulfate ions, becoming ligands, can decrease the activity of supported palladium–copper complexes [31, 32]. …”

Natural Clinoptilolite Based Solid-State Compositions for Low-Temperature Air Purification from Sulphur Dioxide

“…the interactions of water molecules with the surface of chemically modified clinoptilolite are weaker and the thermodynamic water activity increases. Copper(II) salts are expected catalysts of various redox reactions in which gaseous toxic substances participate [7,8].…”

Water vapor adsorption by nanostructured polyphase compositions based on the solid component of welding aerosol

“…It is well known that the activity of oxide and metal catalysts as well as catalysts formed as a result of anchoring metal complexes on various supports in the process of air purification from gaseous toxicants (CO, SO 2 and O 3 ) substantially depends on the water content in them. In some cases, the activity of the catalysts can be lost because of the water adsorption from the gas–air mixture: water molecules are able to block surface catalytic sites and/or change chemical properties of catalyst surfaces (Rakitskaya and Ennan, 2012). The blockage of the active sites is caused by the competition between water and other gaseous molecules for active sites of catalysts (Shaw et al., 1995; Stenger et al., 1993; Tortorelli et al., 2014).…”