Supercritical water (SCW; above 374°C & 22 MPa) possesses the characteristics of non-polar solvents. It has been studied as a promising medium for decomposition of hazardous organics. Experimental research has been conducted to determine the phase behavior of SCW and organics in an oxidative environment via a Diamond Anvil Cell, coupled with a Fourier Transformed Infrared Spectrometer, an optical stereomicroscope and a high-resolution 3CCD camera. Homogeneous phases in H2O-O2, H2O-naphthalene and H2O-O2-naphthalene systems were identified. Flameless oxidation was observed to take place in the homogeneous phases. The chemical evolution and destruction rates of naphthalene/decachlorobiphenyl/cellulose during supercritical water oxidation (SCWO) were established using a batch reactor-based system, simulating practical conditions. Reaction pathways in SCWO were established for naphthalene, decachlorobiphenyl and the industrial sludge. They suggest the involvement of radicals in the reaction mechanism. In the proposed mechanism, ionic reactions were coupled with radical reactions. A significant role of intermediates during SCWO of organics is postulated and explained for the first time. A high activation energy of 139 kJ/mol indicated that the homogeneous SCWO of naphthalene was kinetic-controlled rather than diffusion-controlled. Complete elimination of typical noxious products NO x associated with hydrocarbon-air flames was confirmed in the SCWO of sludge wastes. / A new function describing H2O-O2 interactions under SCW conditions has been determined. It allows for calculations of the critical properties and phase behavior of SCW-O2 system. This function can be applied to determine the effect of pressure on the reaction rate constants in supercritical water.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.84448 |
| Date | January 2003 |
| Creators | Xu, Sikun, 1966- |
| Contributors | Kozinski, Janusz A. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Mining, Metals and Materials Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001985281, proquestno: AAINQ88601, Theses scanned by UMI/ProQuest. |
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