Adsorption studies evaluating codisposal of coal gasification ash with wastewater sludges containing polycyclic aromatic hydrocarbons
The extent to which polycyclic aromatic hydrocarbons (PAHs) are sorbed onto gasifier ash was investigated in batch and column sorption studies. The batch studies involved characterizing the adsorption and desorption of phenanthrene, anthracene, benzo(a)pyrene, and quinoline on gasifier ashes from four coal gasification processes. The surface area of ashes ranged from <1 to >30 m/sup 2//g. Isotherms representative of adsorption and desorption over wide ranges in equilibrium concentrations of the PAHs were determined. Five sorption models, Freundlich, Langmuir, Henry's Law, BET (Brunauer, Emmett, and Teller), and Redlick-Peterson were examined to determine which model best described the adsorption/desorption characteristics of the PAHs on the ashes. Regression analyses indicated that the Freundlich and Langmuir models were more descriptive than either Henry's Law or the BET model. To evaluate the sorption of PAHs on gasifier ashes in a landfill scenario, organic wastes known to contain leachable quantities of PAHs were placed in 5-cm-diam columns overlying various quantities of gasifier ash. The columns were continually leached with distilled water over 3 months, representing greater than 80 column volumes over the duration of the study. Both the batch and the column results indicated that a significant portion of the PAHs sorbed on gasifier ashes was tightly bound or desorbed at a very slow rate. The rate at which this desorption occurs is very critical. For example, if the rate is slow enough to allow degradation, codisposal of wastewater sludges with gasifier ash may be an effective method of disposal. However, before such disposal is implemented, long-term (5- to 10-year) field studies should be conducted to evaluate potential releases of PAHs to groundwater under real-world conditions.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6401704
- Report Number(s):
- ORNL/FETEP-20; ON: DE87013378
- Resource Relation:
- Other Information: Paper copy only, copy does not permit microfiche production. Original copy available until stock is exhausted. Environmental Sciences Division Publication No. 2786
- Country of Publication:
- United States
- Language:
- English
Similar Records
Equilibrium adsorption of polycyclic aromatic hydrocarbons from water onto activated carbon
Determination of the adsorptive capacity and adsorption isotherm of vapor-phase mercury chloride on powdered activated carbon using thermogravimetric analysis
Related Subjects
ADSORPTION ISOTHERMS
COMPARATIVE EVALUATIONS
COAL GASIFICATION PLANTS
SOLID WASTES
WASTE WATER
COAL LIQUEFACTION PLANTS
POLYCYCLIC AROMATIC HYDROCARBONS
ADSORPTION
SLUDGES
WASTE DISPOSAL
SORPTIVE PROPERTIES
WATER TREATMENT
ANTHRACENE
BENZOPYRENE
DESORPTION
HAZARDOUS MATERIALS
PHENANTHRENE
QUINOLINES
SANITARY LANDFILLS
STABILIZATION
SURFACE AREA
AROMATICS
AZAARENES
AZINES
CONDENSED AROMATICS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN COMPOUNDS
INDUSTRIAL PLANTS
ISOTHERMS
LIQUID WASTES
MANAGEMENT
MATERIALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PYRIDINES
SORPTION
SURFACE PROPERTIES
WASTE MANAGEMENT
WASTES
WATER
010404* - Coal
Lignite
& Peat- Gasification