Adsorption of sulfur dioxide

The adsorption of sulfur dioxide of the catalysts rapidly decreased with the vanadium content of the samples. As sulfur dioxide is not chemisorbed on bulk vanadium pentoxide and also appears not to chemisorb on vanadate species, on V20s/Y-Al203 catalysts this probe can be considered to be selective for the titration of the basic sites of vanadium-free alumina. Thus, by selectively probing uncovered alumina, SO2 further allows the distinction between the acid-base features of the vanadium oxide layer and those of uncovered alumina. 

It is well known that small pores, similar in size the adsorbate molecule, enhance the adsorption potential resulting in strong adsorption forces. Moreover, in the case of adsorption of sulfur dioxide it was demonstrated that oxidation to sulfur trioxide occurs mainly in the 7 A pores [76]. With an increase in the... 

Lisovskii, A., Shter, G.E., Semiat, R., and Aharoni, C. (1997). Adsorption of sulfur dioxide by active carbon treated by nitric acid II Effect of preheating on the adsorption properties. Carbon, 35, 1645-8. 

Anurov, C.A. (1996). Physicochemical aspects of the adsorption of sulfur dioxide by carbon adsorbents. (Uspekhi Khimit) Russ. Chem. Rev., 65, 663—76. 

Stern, F.R. "Laboratory Kinetic Studies on Dry Adsorption of Sulfur Dioxide Using Nahcolite and Trona" MS Thesis, University of North Dakota, Grand Forks, N.D., 1978. 

Another well-known system where snrface chemistry was found crucial for removal of pollutants is adsorption of sulfur dioxide. Besides having a certain distribution of pore sizes, carbons for this purpose should be rich in surface basic groups [323-325], They are able to specifically attract sulfur dioxide molecules and thus increase the total capacity of carbons for their removal. 

Adsorption of sulfur dioxide and its oxidation to snlfnr trioxide or snlfuric acid is an interesting way to remove snlfnr dioxide from fine gases (see Chapter 6). 

The evidence on adsorption of sulfur dioxide in micropores in the absence of oxygen was found by Molina-Sabio and co workers [27]. While calculating the micropore volumes of various carbons using CO2, N2, and SO2, a relatively good agreement in the values was obtained, A small discrepancy found in the case of SO2 was explained by the polarity effect. The strraig adsorptive -adsorptive interaction in the gas phase caused weaker adsorbent-adsorbate interaction than in the case of N2 and CO2. 

F ure 6.31. Heat exchange during adsorption of sulfur dioxide at 250°C as a function of its pressure andfor different nickel oxide pretreatments... 

Using the time lag equation (12.2-24), a value for the Knudsen diffusivity of 0.769 is obtained. The diffusion coefficient obtained from the short time analysis is 5% smaller than the time-lag diffusivity. This small difference could be attributed to the experimental error or it could be attributed to a very small adsorption of sulfur dioxide on analcite particle. 

Sydberger, T., and Vannerberg, N. G. (1972). Influence of the relative humidity and corrosion products on the adsorption of sulfur dioxide on metal surfaces. Corros. Sci., 72(10), nS-lM. 

Processes for Adsorption of Sulfur Dioxide from Flue Gas... 

DeBarr, J.A. Lizzio, A.A., and Daley, M.A., Adsorption of sulfur dioxide on bituminous coal char and activated carbon fiber. Energy Fuels, 11(2), 267-271 (1997). 

The primary cause of atmospheric corrosion is dry deposition, which consists mainly of the adsorption of sulfur dioxide. The amount deposited is proportional to the concentration in the atmosphere. Different materials are subject to different deposition rates. Rusty steel surfaces will adsorb SO2 quantitatively at high relative humidities, whereas the deposition on copper, and particularly aluminum, is much less. The rate of dry deposition of other sulfur compounds is less than that of sulfur dioxide. 

Mangim CL, DeBarr JA, Economy J. Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers. Carbon 2001 39 1689-96. 

Examples The roasting of ores, the chemical adsorption of hydrogen sulfide by metal oxides (forming sulfides), the conversion of a metal oxide with a volatile non-metal oxide into a salt (e.g., the chemical adsorption of sulfur dioxide and oxygen by calcium oxide), the reductive chlorination of ilmenite (iron titanate) whereby iron chloride and titanium oxide are formed. In some processes a second solid reactant is present (e.g., carbon) that also reacts with the gaseous reactant, forming another gaseous reactant (e.g., carbon monoxide). 

In recent years it has been recognized that reactions involving porous solids (e.g., the reduction of iron ore pellets or sinter and the adsorption of sulfur dioxide by limestone) are at least as important as reactions involving... 

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