Extraction of toxic organic contaminants from wood and photodegradation of toxic organic contaminants
US5476975A · kind A · utility
Inventors
Key dates
| Filing date | Jul 8, 1994 |
| Grant date | Dec 19, 1995 |
| Priority date | — |
| Expiry date | Jul 8, 2014 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA62D2101/28
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A process is provided herein for extracting organic toxic contaminants including pentachlorophenol, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans, from wood, e.g., utility poles, fence posts, or railway ties. The process comprises extracting the wood with a supercritical fluid in conjunction with an entrainer having wood swelling properties and an agent to break the hydrogen bond between the organic toxic contaminants and the wood, at conventional supercritical fluid extraction temperatures and pressures. The process is further improved by exposing, either in a slurry of the wood phase, or in a liquid phase resulting from such extraction, the contaminants to UV, e.g., sunlight, in the presence of a photosensitizer. The present invention also provides for the photodegradation of a solution of organic toxic chemicals including pentachlorophenol, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans, by exposing such solution to UV, e.g., sunlight, in the presence of a photosensitizer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.