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Tokyo, June 28, 2000 -- In cooperation with the Japan Fine Ceramics Center(JFCC), Fujitsu Laboratories Ltd. has succeeded in developing a new technology for breaking down environmentally harmful dioxin gases that is over 100 times more effective than previous methods. Based on a fusion of plasma and catalyst technologies, the newly developed Plasma-Assisted Catalytic Technology efficiently decomposes and renders harmless dioxin gases in high concentrations of 100 micrograms per cubic meter of nitrogen.
The research breakthrough is expected to lead to development of practical applications to greatly reduce harmful dioxin emissions.
In recent years, dioxin emissions from waste incinerators and other facilities have become a major environmental and public health problem. Dioxins, which are produced when organic compounds containing chlorine are burned, is the generic name for organic chloride compounds containing two benzene rings and made up of carbon, oxygen, hydrogen, and chlorine. The toxicity of these compounds varies, depending on the position of the bonds between the benzene rings and the chlorine, with the compound known as 2378TCDD
known to be the most toxic.
Development Background
Complete combustion and processing of discharged gasses is important for suppressing emissions of dioxin into the atmosphere at waste incinerators. Among the most dependable methods of processing gas emissions are those that decompose dioxin into harmless substances. Plasma decomposition technology has proven to be one of the most effective of these to date, and researchers have been pursuing application of this technology for decomposing dioxin gases in high concentrations of about 1 microgram per cubic meter.
The idea for Plasma-Assisted Catalytic Technology can be traced back to technology developed for the call speech path components of reed switches used in telephone switching systems manufactured by Fujitsu. This technology was based on the new concept of fusing plasma and a catalyst, for which Fujitsu obtained patents in Japan (1996) and the United States (1995). Following the initial development of the Plasma-Assisted Catalytic Technology method, researchers tested and confirmed its ability to decompose carbon dioxide, nitrogen oxide, and fluorocarbons, and its effectiveness in the decomposition reactions of a variety of gases has been clearly shown.
Details of Plasma-Assisted Catalytic Technology Experiment
With the Plasma-Assisted Catalytic Technology method as foundation, researchers, using a catalyst of platinum and optimizing applied voltage and frequency for the plasma generation, succeeded in breaking down and rendering harmless high-density dioxin gases at concentrations of about 100 micrograms per cubic meter of nitrogen.
1234TCDD , a compound with the same composition but different chemical properties (i.e., an isomer) as the dioxin compound 2378TCDD, was used to evaluate the experiment. In the experiment, a number of improvements were made to previous Plasma-Assisted Catalytic Technology methodologies, including the use of a heat resistant tubular apparatus in which dioxin could be introduced. A platinum-plated internal electrode was placed in the center of the tube, and the outside was made of glass.
Several tens of kilovolts were applied between an electrode outside of the glass and the central electrode, and nitrogen gas containing 1234TCDD (100 micrograms/N cubic meters) was injected into the apparatus. Researchers were able to verify a decomposition rate of more than 99%, and confirmed that the rate of decomposition varied in accordance with the applied voltage and frequency. Analysis of the residue following decomposition showed no traces whatsoever of such toxic substances as benzene and chlorobenzene.
Now that the Plasma-Assisted Catalytic Technology method has been shown effective in decomposing dioxins, Fujitsu anticipates that the next step will be accelerated research on dioxin decomposition using high-performance ceramic catalysts. The company also expects that practical applications of the present technology will be developed once it is made available to manufacturers in the field.
Terminology
- 1) Plasma:
- Is formed when free electrons in an electric field receive energy from that field and are accelerated, and collision with neutral molecules causes excitation, disassociation, and ionization of these molecules. As a whole, plasma is neutral. In this experiment, Fujitsu used a low-temperature plasma domain.
- 2) Catalyst:
- A substance that, in small amounts, controls the speed, the selectivity, and stereo regularity of thermodynamic reactions, without itself being consumed.
- 3) Dioxins:
- A general term for a group of extremely toxic organic compounds, of which 2378TCDD is a typical example. They are the most toxic of synthetic compounds, and are known to be carcinogenic and teratogenic. Their toxicity varies, depending on the number and position of the chlorine atoms.
- 4) 1234TCDD:
- One of the dioxins whose toxicity has not been recognized.
Since it is structurally similar to 2378TCDD, it is often used in evaluation of dioxins.
[Corporate Information]
- Fujitsu Limited
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Fujitsu Limited (TSE: 6702) is a leading provider of Internet-based information technology solutions for the global marketplace. Comprising over 500 group companies and affiliates worldwide -- including ICL, Amdahl and DMR Consulting -- it had consolidated revenues of 5.26 trillion yen ($49.6 billion) in the fiscal year ended March 31, 2000.
Fujitsu's pace-setting technologies, world-class computing and telecommunications platforms, and global corps of over 60,000 systems and services experts make it uniquely positioned to unleash the infinite
possibilities of the Internet to help its customers succeed. Altogether, the Fujitsu Group has 188,000 employees and operations in over 100 countries.
Internet: http://www.fujitsu.com
Fujitsu. The Possibilities Are Infinite
- Fujitsu Laboratories Ltd.
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Founded in 1968 as a wholly owned subsidiary of Fujitsu Limited, Fujitsu Laboratories Limited is one of the premier research centers in the world. With five laboratories in Japan and one in the United States, the organization conducts a wide range of basic and applied research in the areas of Multimedia, Personal Systems, Networks, Peripherals, Advanced Materials and Electronic Devices.
* All company/product names mentioned may be trademarks or registered trademarks of their respective holders and are used for identification purpose only.
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