Copper adsorption effects

In the same Figures the effect of copper content on the catalytic activity can be observed for both Cu-HZSM5 and Cu-NaY catalysts. In fact, a decrease of NOx conversion from 34 to 25% at 400°C was observed when the copper content of Cu-HZSM5 was lowered from 3.28 to 0.92 wt%. Similarly, a maximum NOx conversion of only 12% was obtained for Cu-NaY containing 2.49 wt% of copper. Adsorption effects do not allow significant differences in hydrocarbon... 

Variation of heats of adsor-ption on different major crystal faces of copper. The effect of the crystal face of the adsorbent on physical adsorption has been treated theoretically by Barrer (153) for covalent surfaces and by Orr (151) and by Lenel (154) for dielectric surfaces. The vertical interactions between a nonpolar molecule and a polycrystalline metal surface have been independently treated by Lennard-Jones (155), by Bardeen (156), and by Margenau and Pollard (157). Considering the theoretical limitations involved in the last treatment, the observed agreement between the values calculated theoretically and the experimental values is acceptable. At present no explicit theoretical treatment of the physical adsorption of a nonpolar gas molecule on a single crystal metal surface in terms of the crystal parameter and geometry of the latter is available. 

Zarzyeki, R. et al., The effect of chitosan form on copper adsorption, in Environmental Engineering Studies, edited hy Pawlowski et al., Kluwer Academic/Plenum Publishers, New York, 2003. 

Polystyrene-divinylbenzene polymer matrices, with a thiourea functional group, show good selectivity towards iron and copper, and effectively bind and remove them, both in batch and column operations. The adsorption mechanism can be explained by the coordination between ligand and metal ions [12]. 

Kaoser S, Barrington S, Elektorowicz M, Wang L. (2004a). Copper adsorption with Pb and Cd in sand-bentonite liners under varions pHs. Part I. Effect on total adsorption. Journal of Environmental Science and Health 39(09) 2241-2256. 

Y. Champion, F. Bernard, N. Millot, P. Perriat, Surface adsorption effects on the lattice expansion of copper nanocrystals. Appl. Phys. Lett. 86(23), 231914 (2005)... 

Wu S, Lipkowski J, TylizczakT and Hitchcock H P 1995 Effect of anion adsorption on early stages of copper electrocrystallization at Au(111) surface Prog. Surf. Sc/. 50 227-36... 

Adsorption Processes. More recendy, pressure swing adsorption (PSA) processes utilizing a high selectivity copper adsorbent have been utilized to effectively separate carbon monoxide from blast furnace gas and coke oven gas (97—101). 

Adsorbed molecules are more strongly held at the sites where the weakest metal-metal bonding is to be found, and these conespond to the active sites of Langmuir. A demonstration of this effect was found in smdies of the adsorption of H2S from a H2S/H2 mixture on a single crystal of copper of which die separate crystal faces had been polished and exposed to die gas. The formation of copper sulphide first occuiTed on die [100] and [110] planes at a lower H2S partial pressure dran on die more densely packed [111] face. Thus die metal atoms which are less strongly bonded to odrer metal atoms can bond more strongly to die adsorbed species from die gas phase. 

Henriques, C., Ribiero, M., Abreu, C. el al. (1998) An FT-IR study of NO adsorption over Cu-exchanged MFI catalysts Effect of Si/Al ratio, copper loading and catalyst pre-treatment, Appl. Catal. B Environ., 16, 79. 

Harter R.D. Effect of soil pH on adsorption of lead, copper, zinc, and nickel. Soil Sci Soc Am J 1983 47 47-51. 

Yoshimura et al. [193] carried out microdeterminations of phosphate by gel-phase colorimetry with molybdenum blue. In this method phosphate reacted with molybdate in acidic conditions to produce 12-phosphomolybdate. The blue species of phosphomolybdate were reduced by ascorbic acid in the presence of antimonyl ions and adsorbed on to Sephadex G-25 gel beads. Attenuation at 836 and 416 nm (adsorption maximum and minimum wavelengths) was measured, and the difference was used to determine trace levels of phosphate. The effect of nitrate, sulfate, silicic acid, arsenate, aluminium, titanium, iron, manganese, copper, and humic acid on the determination were examined. 

Cathodic stripping voltammetry has been used [807] to determine lead, cadmium, copper, zinc, uranium, vanadium, molybdenum, nickel, and cobalt in water, with great sensitivity and specificity, allowing study of metal specia-tion directly in the unaltered sample. The technique used preconcentration of the metal at a higher oxidation state by adsorption of certain surface-active complexes, after which its concentration was determined by reduction. The reaction mechanisms, effect of variation of the adsorption potential, maximal adsorption capacity of the hanging mercury drop electrode, and possible interferences are discussed. 

---