Decomposition of PVC and Ion exchange resin in supercritical water

  • Lee, Sang-Hwan (Shinshu University Department of Chemistry and Material Engineering Faculty of Engineering) ;
  • Yasuyo, Hosgujawa (Shinshu University Department of Chemistry and Material Engineering Faculty of Engineering) ;
  • Kim, Jung-Sung (Daegu University chemistry education) ;
  • Park, Yoon-Yul (Life science Institute, Busan Collage of Information Technology) ;
  • Hiroshi, Tomiyasu (Shinshu University Department of Chemistry and Material Engineering Faculty of Engineering)
  • Published : 2005.05.20

Abstract

This experiment was carried out at 450"C, which is relatively lower than the temperature for supercritical water oxidation (600-650$^{\circ}C$). In this experiment, the decomposition rates of various incombustible organic substances were very high. In addition, it was confirmed that hetero atoms existed in organic compounds and chlorine was neutralized by sodium(salt formation).However, to raise the decomposition rate, relatively large amount of sodium nitrate(3-4 times the equivalent weight) was required. When complete oxidation is intended as in the case with PCB, the amount of oxidizer and decomposition cost is important. But when vaporization reduction is required as in the case with nuclear wastes, the amount of radioactive wastes increases instead. But as can be seen in the result of XRD measurement, unreacted sodium nitrate remained unchanged. If oxidation reaction of organic substance simply depends on collision frequency, unreacted sodium nitrate can be recovered and reused, then oxidation equivalent weight would be sufficient. In the gas generated, toxic gas was not found. As the supercritical water medium has high reactivity, it is difficult to generate relatively low energy level SO$_{X}$, and NO$_{X}$.

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