Estimating desorption kinetic rates from sequential batch experiments
- Rutgers Univ., New Brunswick, NJ (United States). Dept. of Environmental Science
A serious limitation in the modeling of the transport and fate of contaminants in soil/water systems is the lack of information regarding the desorption kinetics of substances from contaminated materials. A frequently made assumption is that adsorption/desorption processes are completely reversible and fast, such that a single equilibrium expression can be used to estimate the distribution of a substance between solid and liquid phases. A reliable method for examining desorption kinetics is needed. The paper presents results from an experimental method the authors developed to estimate desorption kinetics of organic substances from contaminated materials. The method involves sequential batch experiments operated in a kinetic mode. A mass of contaminated soil is introduced into a volume of uncontaminated liquid. The systems are studied until they reach an apparent equilibrium, whereupon a new desorption driving force is established by replacing a volume of the now contaminated liquid with an equal volume of uncontaminated liquid. All input and output is accomplished by syringe inclosed vials to minimize losses. The resultant data are modeled using a Marquardt-Levenberg algorithm from which cumulative mass desorbed is modeled as a limited first-order growth process, which fits the data well. Total experimental plus analytical error has been calculated for all experiments to date and is less than 5%. Organic substances studied include benzene, toluene, and meta-xylene and soils include both reference soils and contaminated site soils.
- OSTI ID:
- 455288
- Report Number(s):
- CONF-961149-; TRN: IM9716%%137
- Resource Relation:
- Conference: 17. annual meeting of the Society of Environmental Toxicology and Chemistry: partnerships for the environment - science, education, and policy, Washington, DC (United States), 17-21 Nov 1996; Other Information: PBD: 1995; Related Information: Is Part Of SETAC 17. annual meeting -- Abstract book. Partnerships for the environment: Science, education, and policy; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Desorption kinetics of polycylic aromatic hydrocarbons in coal fines and coal contaminated sediments
Description of time-varying desorption kinetics. Release of naphthalene from contaminated soils