Spectroscopic analysis and performance of an experimental copper/zinc impregnated, activated carbon

Comparative study on removal efficiency of impregnated carbons for hydrogen cyanide vapors in air depending on their phase composition and porous textures

“…The differences between our data (Tables 2 and 3) and the binding energies of the Cu(2p 3/2 ) peaks reported by other authors [14,21,30] can be ascribed to the presence of incompletely decomposed CuCO 3 and Cu(OH) 2 forming shoulders on the Cu(2p 3/2 ) peaks toward the higher binding energies.…”

“…In this sense the application of sample VSZ (with simultaneous participation in the process of Cu and Zn phases while the function of Ag is not associated with HCN) would lead to a reaction with HCN involving the Zn phase until its exhaustion, since there is no mechanism in the copper/zinc formulation for cyanogen removal [14].…”

“…In the first step HCN is mainly chemisorbed by the Zn phase, since according to [14] the diffusion resistance makes the Cu phase less accessible. In the second step, as the Zn phase is consumed, the HCN interaction with the Cu phase becomes dominating (Eq.…”

“…In this sense, the most promising combination [2,14,23,24] is that of Cu-and Zn-containing material. The latter could also contain Ag (for catalytic oxidation of AsH 3 and PH 3 ), pyridine (since it reacts as a nucleophilic agent against ClCN vapors, especially in the presence of moisture, and also it increases the basicity and the phase stability of impregnated carbons), etc.…”

“…In spite of their high removal efficiency with respect to cyanide compounds in air [11][12][13], impregnated carbons containing Cr 6+ are considered not to be advantageous by the US Environmental Protection Agency [14] due to the -cancer-producing effect of some of Cr 6+ species [15] on people in industry and the army, where the corresponding gas masks and collective protection filters are used [2]; -problems associated with the annihilation of this type of impregnated carbons after the date when, according to the producer, they can no longer be used; -irreversible and easy deactivation of the carbons under the effect of temperature [16] and/or enhanced humidity [17][18][19][20][21].…”