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Ethylenediaminetetraacetic acid (EDTA) was decomposed by supercritical water oxidation (SCWO) in a tubular plug-flow reactor. The effect of the oxidant amount on the decomposition rate and efficiency was more significant at lower temperature. Also, excess oxidant played a key role in decreasing the activation energy for EDTA decomposition as CODCr. The nitrogen from EDTA was found to transform into NO3 -−N by thermal decomposition, while a portion of the nitrogen of EDTA and NO3 -−N was transformed into NH4 +−N and finally converted to N2 gas in the SCWO process. The decomposition kinetics of EDTA as CODCr in the SCWO process was described by a global rate expression.

Metal complex ethylenediaminetetraacetic acid (NaFeEDTA) was effectively decomposed by supercritical water oxidation (SCWO) with hydrogen peroxide in a plug-flow reactor. The effects of the oxidant amount and temperature on the decomposition rate and efficiency were more significant than that of pressure. The amount of oxidant significantly affected the decomposition rate and efficiency at lower temperatures. The decomposition kinetics of NaFeEDTA as the total organic carbon in the SCWO process was described using a global rate expression. In addition, as a byproduct, hematite (α-Fe2O3) in the range of 50−450 nm with regular shape was obtained from the decomposition of NaFeEDTA by the SCWO process. The size and shape of the metal oxide was controlled by the SCWO condition.

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