Wet oxidation of phenol and naphthalene (as a surrogate PAH) in aqueous and sludge solution: application to coal-conversion wastewater and sludge treatment. [In autoclaves: 130 to 250/sup 0/C; 6 to 11 MPa oxygen; in water solution]
The wet oxidation of phenol and naphthalene in distilled water and municipal sludge has been investigated in a 1-L autoclave at temperatures from 130 to 250/sup 0/C, oxygen presures of 6 to 11.2 MPa, and initial phenol and naphthalene concentrations of 10 mg/L to 16 g/L and 10 mg/L to 420 mg/L, respectively. The reaction of phenol in water is rapid; 95% of the phenol degrades in less than 15 min at operating temperatures above 175/sup 0/C. The oxidation of phenol in sludge is mass-transfer limited and therefore yields lower rate-constant values. The reaction of phenol in water or sludge is postulated to involve a free-radical mechanism and proceeds in three steps: an induction step, a rapid first-order step, and a slower first-order step. The rapid first-order step for the phenol-water study is temperature dependent and follows the Arrhenius expression given. The slower first-order step is due to an inhibition of the rate of phenol oxidation by organic intermediates. The major organic intermediates formed during the wet oxidation of phenol are hydroquinone, catechol, succinic acid, and glycolic acid. Greater than 98% oxidation of naphthalene at milligram-per-liter concentrations in water was observed in less than 10 min. The rate of oxidation of naphthalene in sludge is inhibited by either mass transfer and/or oxidizable organics. A pseudo-first-order reaction was observed for the oxidation of naphthalene in water and sludge. The first-order rate constants are given. Essentially none of the naphthalene is completely oxidized to carbon dioxide and phthalic anhydride is the principal product for the wet oxidation of naphthalene.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6333839
- Report Number(s):
- ORNL/TM-8576; ON: DE83012526
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL GASIFICATION PLANTS
WASTE WATER
COAL LIQUEFACTION PLANTS
NAPHTHALENE
OXIDATION
PHENOL
SIMULATION
ACTIVATION ENERGY
ARRHENIUS EQUATION
AUTOCLAVES
BENCH-SCALE EXPERIMENTS
COAL GASIFICATION
COAL LIQUEFACTION
MASS TRANSFER
PHTHALIC ACID
RADICALS
SLUDGES
TEMPERATURE DEPENDENCE
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CONDENSED AROMATICS
DICARBOXYLIC ACIDS
ENERGY
EQUATIONS
GASIFICATION
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INDUSTRIAL PLANTS
LIQUEFACTION
LIQUID WASTES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHENOLS
THERMOCHEMICAL PROCESSES
WASTES
WATER
010404* - Coal
Lignite
& Peat- Gasification
010405 - Coal
Lignite
& Peat- Hydrogenation & Liquefaction
010800 - Coal
Lignite
& Peat- Waste Management