Absorption rates oxygen removal

The oxidation process takes place once a fresh coal surface is exposed to air however, the oxygen absorption rate is inversely proportional to time if the temperature remains constant. Therefore, if the coal is stockpiled so that the temperature in the pile does not rise appreciably insofar as the heat is removed at least as fast as it is generated by the oxidation process, the oxidation rate and, thus, the deterioration or weathering rate of the coal will lessen with time (Vaughn and Nichols, 1985). 

Hydrogen sulfide in the air is oxidized at a relatively slow rate by molecular oxygen (02) but at a much faster rate by hydroxide (OH) radicals, forming the sulfhydryl radical and ultimately sulfur dioxide or sulfate compounds (Hill 1973 NSF 1976). Sulfur dioxide and sulfates are eventually removed from the atmosphere through absorption by plants and soils or through precipitation (Hill 1973). 

The oxygen balance in the absorption tank must account for mass transfer from the air, but neglects the low rates of oxygen supply and removal of the feed and effluent streams. This gives... 

Further information to help determine the CS2 oxidation mechanism comes from photochemical studies. Kondratiev and Yakovlevairradiated 16-55 torr CS2 in the presence of 40-100 torr O2 with light at 2000 A. The primary products were CS and S atoms. The major final products were SO2 and OCS, the latter undergoing further oxidation. Wright studied the isothermal, room temperature oxidation initiated by flash photolysis, as well as the flash photolysis of pure CS2. After flashing pure CS2, he observed the absorption spectra of CS and S2. The S2 disappeared rapidly, following second-order kinetics. CS was removed at the walls. In the presence of oxygen, the S2 was diminished, but its rate of disappearance was unaffected. SO2 and S2O absorption spectra were also... 

More recently, Boden and Thrush have examined the reaction of O-I-C2N2 in a flow reactor using absorption spectroscopy to measure CN concentrations. In the temperature range of 570-687 °K they found the rate coefficient for oxygen atom removal to be 2.5 0.3 x 10 exp (— ll,000/l r)l.mole sec 24 was reported... 

Iron removal Increased iron and ferritin levels are found in approx. 30% of patients with chronic hepatitis B or C. Several studies have shown that the success rate of interferon therapy is reduced in the presence of elevated liver iron values. This is attributed to the fact that iron overload inhibits not only lymphocyte proliferation, but also the function of killer cells and B cells as well as the production of antibodies. Iron plays a role in the formation of free radicals and the occurrence of dangerous lipid peroxidations, (s. pp 68, 401) Furthermore, iron, like oxygen radicals, promotes fibrogenesis. Iron removal leads to an improvement in laboratory parameters and better response to interferon-a therapy. (217, 243) On the other hand, the iron level is reduced as a result of successful IFN therapy. In the case of a higher serum iron status before the initiation of interferon therapy, venesections at one week intervals should be considered, if necessary until normal laboratory values (iron, ferritin, transferrin saturation) have been restored. During interferon therapy, a low-iron diet is advisable, as is the consumption of 2 x 1 cup of black tea (in the morning and at noon) to reduce iron absorption through chelate formation ( cheap, free of side effects and useful )- (s. p. 625) Silymarin also leads to iron mobilization due to chelate formation. 

Gas-to-liquid mass transfer is a transport phenomenon that involves the transfer of a component (or multiple components) between gas and liquid phases. Gas-liquid contactors, such as gas-liquid absorption/ stripping columns, gas-liquid-solid fluidized beds, airlift reactors, gas bubble reactors, and trickle-bed reactors (TBRs) are frequently encountered in chemical industry. Gas-to-liquid mass transfer is also applied in environmental control systems, e.g., aeration in wastewater treatment where oxygen is transferred from air to water, trickle-bed filters, and scrubbers for the removal of volatile organic compounds. In addition, gas-to-liquid mass transfer is an important factor in gas-liquid emulsion polymerization, and the rate of polymerization could, thus, be enhanced significantly by mechanical agitation. 

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