Desorption kinetics of polycylic aromatic hydrocarbons in coal fines and coal contaminated sediments

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6677534

Shorten, C V

Batch with fluid replacement (BFR) and time resolved leaching (TRL) methods were developed to determine the desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) in coal fines and coal contaminated sediments using various organic solvent/water mixtures. The two techniques were relatively comparable, with a given solvent, solid phase, and experimental time scale. TRL is the method of choice for short term (one day or less) experiments while BFR is better suited for long term desorption studies. Both phenanthrene and chrysene desorbed from coal contaminated sediments following first order kinetics. Predicted equilibrium concentrations ((C){sub eq}) and desorption rate constants (k{sub d}) were estimated using both one and two stage first order kinetic models. Acetone/water solvent mixtures induced desorption of greater amounts of phenanthrene than did more highly polar methanol/water mixtures, and desorption rate coefficients were higher in the acetone mixtures than they were in the methanol mixtures. As predicted by cosolvent theory and microscopic equilibrium, k{sub d} values increased (slightly) with increasing mole fraction cosolvent and (C){sub eq} values also increased (significantly) with increasing mole fraction cosolvent. Experimental design and period of observation of the desorption process appeared to be important in the consideration of observed desorption constants. Solids concentration in the BFR reactors was varied from 1000 to 100,000 mg/l. Total mas of both compounds released to the liquid phase increased significantly with increasing suspended solids concentrations, but relationship between rate constants and solids concentration were more complex.

• Research Organization: Clemson Univ., SC (USA)
• OSTI ID: 6677534
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
54 ENVIRONMENTAL SCIENCES
COAL FINES
SORPTIVE PROPERTIES
POLYCYCLIC AROMATIC HYDROCARBONS
DESORPTION
SEDIMENTS
ACETONE
CHEMICAL REACTION KINETICS
CHRYSENE
EQUILIBRIUM
KINETIC EQUATIONS
LEACHING
MATHEMATICAL MODELS
MEASURING METHODS
METHANOL
ORGANIC SOLVENTS
PHENANTHRENE
QUANTITY RATIO
TIME DEPENDENCE
WATER
ALCOHOLS
AROMATICS
CONDENSED AROMATICS
DISSOLUTION
EQUATIONS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
KETONES
KINETICS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SOLVENTS
SURFACE PROPERTIES
010900* - Coal
Lignite
& Peat- Environmental Aspects
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)