Oxidation and hydrolysis of acetic acid and methylene chloride in supercritical water as a means of remediation
- Massachusetts Institute of Technology, Cambridge, MA (United States); and others
Supercritical water oxidation (SCWO) is a promising technology proposed for the destruction of hazardous organic wastes. Unlike its well known behavior under ambient conditions, water above its critical point (374{degrees}C, 221 bar) has properties similar to that of a nonpolar solvent, primarily due to the effect of a decrease in hydrogen bonding and density that occurs near and above the critical point. The result is that nonpolar organics and oxygen exhibit complete solubility in supercritical water, while polar species such as inorganic salts are insoluble and precipitate out. In the single homogeneous phase formed, oxidation of organics with oxygen in supercritical water is rapid and complete to CO{sub 2} and H{sub 2}O. Organic heteroatoms such as halogens, sulfur, or phosphorus are converted to inorganic acids (HCl, H{sub 2}SO{sub 4}, H{sub 3}PO{sub 4}) which precipitate as salts when neutralized with added base, while nitrogen is converted to N{sub 2} and N{sub 2}O. No NO{sub x} compounds are formed due to the relatively low temperatures that exist in the SCWO process (400 - 650{degrees}C) relative to that of air incineration processes (typically 900 - 1300{degrees}C). Oxidation in supercritical water is thus an appealing means of destroying toxic organic compounds while simultaneously separating out undesired inorganics by precipitation. Applications to decontaminating soils and dilute aqueous wastes are of special interest. Earlier work has demonstrated high destruction efficiencies for various organics in SCWO.
- OSTI ID:
- 111514
- Report Number(s):
- CONF-9504110-; TRN: 95:005009-0057
- Resource Relation:
- Conference: 21. Environmental Protection Agency (EPA) annual Risk Reduction Engineering Laboratory research symposium, Cincinnati, OH (United States), 4-6 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of 21st Annual RREL research symposium: Abstract proceedings; PB: 398 p.
- Country of Publication:
- United States
- Language:
- English
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