Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7043319

Lee, Y I

Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/ greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 7043319
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800* -- Coal
Lignite
& Peat-- Waste Management
ADIPIC ACID
CARBOXYLIC ACIDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COBALT
DECOMPOSITION
DESULFURIZATION
DICARBOXYLIC ACIDS
ELEMENTS
FLUE GAS
GASEOUS WASTES
GLUTARIC ACID
HALIDES
HALOGEN COMPOUNDS
IRON
KINETICS
MALEIC ACID
MANGANESE
METALS
MONOCARBOXYLIC ACIDS
NICKEL
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PH VALUE
REACTION INTERMEDIATES
REACTION KINETICS
SULFITES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
VALERIC ACID
WASTES