Issue
Korean Journal of Chemical Engineering,
Vol.24, No.6, 1009-1016, 2007
Cerium(IV)-mediated electrochemical oxidation process for destruction of organic pollutants in a batch and a continuous flow reactor
The mediated electrochemical oxidation (MEO) process with Ce(IV) and nitric acid as the oxidizing medium was employed for the destruction of various model organic pollutants in batch and continuous organic feeding modes. A near complete destruction was observed for all the model organic pollutants studied. The effects of organic concentration, temperature, concentration of Ce(IV), concentration of nitric acid and feeding time on the organic destruction efficiency were investigated. Under the experimental conditions of 80 ℃ and 0.95 M Ce(IV) in 3M nitric acid, nearly 90% destruction was achieved based on CO2 production and 95% based on TOC and COD nearly for all the organic compounds studied in batch organic addition. In the case of continuous organic addition with in situ electroregeneration of Ce(IV) by the electrochemical cell a good destruction efficiency was obtained. For long term organic feeding (120 min) the destruction efficiency was found to be 85% based on CO2 evolution and 98-99% based on TOC and COD analyses. A model was proposed for calculating the CO2 formation constant during the continuous process of organic addition. The model predicted a steady state CO2 evolution pattern for the destruction process during continuous organic feeding. The experimental results obtained confirmed the predicted trends for the destruction process. The changes in enthalpy, entropy, activation energy and free energy for EDTA degradation were found to be 26.7 kJ/mol, .230 J/(mol·K), 29.7 kJ/mol, and 118 kJ/mol respectively.
[References]
  1. Ryan JL, Bray AL, Wheelwright EJ, Bryan GH, Catalyzed electrolytic plutonium oxide dissolution in transuranium elements: A half century. L. R. Morss and J. Fuger Eds., American Chemical Society, Washington, 1992
  2. Zundelevich Y, J. Alloy. Compd., 182, 115, 1992
  3. Farmer JC, Wang FT, Hawley-Fedder RA, Lewis PR, Summers LJ, Foiles L, J. Electrochem. Soc., 139, 654, 1992
  4. Bringmann J, Galla U, Schmieder H, Mediated electrochemi cal oxidation for total degradation of HCH and other pesticides, 5th International HCH and Pesticides Forum, Leioa, Spain, 1998
  5. Nelson N, Platinum Met. Rev., 46, 18, 2002
  6. Sequeira CAC, Santos DMF, Brito PSD, Appl. Surf. Sci., 252(17), 6093, 2006
  7. GEF, On review of emerging innovative technologies for the destruction and decontamination of POPs and the identification of promising technologies for use in developing countries, Report of United Nations Environmental Programme for 2004, Jan. 15, 2004
  8. Steele DF, Platinum Met. Rev., 34, 10, 1990
  9. Balazs B, Chiba Z, Hsu P, Lewis P, Murguia L, Adamson M, Proc. 6th. Int. Conf. Radioactive Waste Management and Environmental Remediation, ICEM 97, Am. Soc. Mech. Eng. New York, 1997
  10. Chung SJ, Balaji S, Matheswaran M, Ramesh T, Moon IS, Water Sci. Technol., 55, 261, 2007
  11. Matheswaran M, Balaji S, Chung SJ, Moon IS, J. Ind. Eng. Chem., 13(2), 231, 2007
  12. Galla U, Kritzer P, Bringmann J, Schmieder H, Chem. Eng. Technol., 23(3), 230, 2000
  13. Raju T, Basha CA, Chem. Eng. J., 114(1-3), 55, 2005
  14. Balaji S, Chung SJ, Thiruvenkatachari R, Moon IS, Chem. Eng. J., 126(1), 51, 2007
  15. Varela J, Oberg S, Neustedter TM, Nelson N, Environ. Prog., 20, 261, 2001
  16. Joshi SR, Kataria KL, Sawant SB, Joshi JB, Ind. Eng. Chem. Res., 44(2), 325, 2005
  17. Chiba Z, Mediated electrochemical oxidation of mixed wastes, Lawrence Livermore National Laboratory, Livermore, CA, UCRLJC-112669, 1993
  18. Balaji S, Kokovkin VV, Chung SJ, Moon IS, Water Res., 41, 1423, 2007
  19. Lee JW, Chung SJ, Balaji S, Kokovkin VV, Moon IS, Chemosphere, 68, 1067, 2007
  20. Kokovkin VV, Chung SJ, Balaji S, Matheswaran M, Moon IS, Korean J. Chem. Eng., 24(5), 749, 2007
  21. Matheswaran M, Balaji S, Chung SJ, Moon IS, Electrochim. Acta, 53, 1897, 2007
  22. Matheswaran M, Balaji S, Chung SJ, Moon IS, Chemosphere, 69, 325, 2007
  23. Moon IS, Korea Patent 10-2005-0045983, May 31, 2005
  24. Lehmani A, Turq P, Simonin JP, J. Electrochem. Soc., 143, 1861, 1996
  25. Tzedakis T, Savall A, J. Appl. Electrochem., 27(5), 589, 1997
  26. Matheswaran M, Balaji S, Chung SJ, Moon IS, Bull. Korean Chem. Soc., 28, 1329, 2007