A NOVEL ENERGY EFFICIENT PLASMA CHEMICAL PROCESS FOR THE DESTRUCTION OF VOLATILE TOXIC COMPOUNDS
Destruction of low-concentrations (below several percent) of toxic volatile compounds from contaminated air stream is encountered at the DOE waste sites in the following instances: (i) off-gases resulting from air-stripping of highly-contaminated water and soil (contaminated with DNAPLs, VOCs, etc), (ii) effluent from the incineration of highly-concentrated combustible hazardous wastes. If the contaminated air stream has concentrations of a few parts per million (ppm) then passive methods, such as activated carbon, can be used successfully. If the concentration level is more than several percent, then thermal incineration can be successfully used. However, in the intermediate range neither of the above processes are suitable [1]. During the past decade or so, non-thermal plasma techniques have been investigated (see the references in [1, 2]) for the remediation of waste streams with concentrations in this intermediate range (to our knowledge, our project was the only one that addressed this problem under the EMSP sponsorship). Our approach is a completely different from those previous non-thermal plasma techniques. The main objective was to investigate the feasibility of a novel plasma chemical process for the remediation of toxic gas mixtures based on an enhanced dissociative electron attachment process that had been discovered in a basic research program: Prior to this project, it had been found that molecules excited to highly-excited states via laser irradiation efficiently attached electrons leading to the dissociation of the molecule (see, [3-6] and references therein). The following tasks were needed to be completed during the three year duration of the project in order to illustrate the feasibility of the new technology: 1. Since the usage of lasers is not cost effective, two discharge based schemes were planned to be investigated for molecular excitation. 2. The basic mechanisms involving dissociative electron attachment to highly-excite d molecules needed to be studied, in order to optimize the process. 3. A bench-top plasma reactor needed to be constructed to conduct actual plasma destruction measurements, so that the destruction efficiency could be quantified. 4. Methodologies for, (a) determination of the destruction efficiency, and (b) analysis of the byproducts 4 from the reactor, needed to be developed. 5. Basic studies needed to be conducted to understand the observations of the remediation studies, and thus to enhance the remediation process. As described below, we have accomplished these objectives, and have illustrated the feasibility of this new technology. However, further research is needed before this technology can be applied in the field.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- OSTI ID:
- 827280
- Report Number(s):
- EMSP-54973; R&D Project: EMSP 54973; TRN: US200426%%701
- Resource Relation:
- Other Information: PBD: 31 Dec 2000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Accelerated cleanup risk reduction
A novel energy-efficient plasma chemical process for the destruction of volatile toxic compounds. 1997 annual progress report