2004 Fiscal Year Final Research Report Summary
Detoxification of persistent organic compounds by a combination of plasma decomposition with in-situ halogen absorption
| Project/Area Number |
15310051
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental technology/Environmental materials
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| Research Institution | Nagoya University |
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Principal Investigator |
MATSUDA Hitoki Nagoya University, Graduate School of Engineering, Professor, 工学研究科, 教授 (80115633)
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| Co-Investigator(Kenkyū-buntansha) |
SHIKIDA Mitsuhiro Nagoya University, Eco Topia Science Institute, Associate Professor, エコトピア科学研究機構, 助教授 (80273291)
KOJIMA Yoshihiro Nagoya University, Eco Topia Science Institute, Associate Professor, エコトピア科学研究機構, 助教授 (80345933)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Halide Gases / Non-thermal Plasma / Oxygen(O_2) / Hydrogen(H_2) / Improvement of Decomposition / Byproducts / Alkaline Absorbent / In-situ Plasma Decomposition |
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| Research Abstract |
In this research, the behavior of non-thermal plasma decomposition of organic halide gases in N_2,O_2N_2 and H_2-N_2 atmospheres was studied. In addition, for the purpose of inhibition of the formation of halogen byproducts and effective detoxification of halides by the in-situ capture of the halogen species, the decomposition of organic halide gases was investigated using a technique of plasma decomposition combined with in-situ gas absorption by alkaline absorbent.
On the plasma decomposition of halide gases (CCl_4,CHF_3 and CHClF_2) in the O_2-N_2 atmosphere, the decomposition ratios of halide gases were lower compared to those in N_2 atmosphere. The amount of CO_2 formed by the oxidation of the carbon (C) in the structure of halide gases was increased with the increase of the concentration of O_2. During the decomposition of CHClF_2 under N_2 atmosphere, CCl_2F_2,HF, HCl,F_2 and Cl_2 were detected, while, in addition, COF_2 and COCl_2 were formed under O_2-N_2 atmosphere. In the cas
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e of the plasma decomposition of CF_4,CHF_3,CHClF_2 and SF_6 in H_2-N_2 atmosphere, the decomposition ratios of CF_4,CHC1lF_2 and SF_6 were higher compared to those in N_2 atmosphere. However, the decomposition ratio of CHF_3 decreased in the presence of H_2. H_2S and HF were formed as the byproducts in the decomposition of SF_6 in H_2-N_2 atmosphere, in addition to F_2 formed in N_2 atmosphere.
When the plasma decomposition was incorporated with in-situ gas absorption by Ca(OH)_2 absorbent on the decomposition of CHClF_2 in O_2-N_2 atmosphere and CHF_3 in H_2-N_2 atmosphere, the decomposition ratios of halides increased, compared to that without Ca(OH)_2. In O_2-N_2 atmosphere, the amount of CO_2 formed during the plasma decomposition of CHClF_2 in the presence of in-situ alkaline absorbent was higher than that without alkaline absorbent. Moreover, it was found that the generation of the halogen byproducts such as HF and COCl_2 in outlet gas was significantly inhibited in plasma decomposition of CHClF_2 incorporated with in-situ gas absorption.
As a result, our work demonstrated the possibility of in-situ alkaline absorbent present in the plasma reaction field to achieve the effective plasma decomposition of halide gases and removal of harmful byproducts. Less
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