Study on supercritical water oxidation of o-dichlorobenzene in a quartz micro-reactor with in situ microscope and Raman spectroscopy

摘要： The supercritical water oxidation (SCWO) of o-dichlorobenzene (o-DCB) in a fused quartz capillary reactor was studied by in situ microscope combined with Raman spectroscopy. The influence of oxidant dosage, reaction temperature and time on the o-DCB degradation efficiency was investigated and the reaction kinetics for CO2 yield was explored as well. The obvious phase change of o-DCB-H2O/H2O2 system was observed during the heating and cooling process. The increase in H2O2 dosage, temperature and time enhanced the o-DCB degradation efficiency. The degradation of o-DCB could be attributed to the simultaneous oxidation induced by HO· and O2. The effect of temperature on the o-DCB degradation efficiency and the CO2 yield was not significant at the lower temperature stage but turned to be important at the higher temperature stage. When the oxidant dosage was twice that of chemometry and the temperature and time were 440.0 °C and 4 min, respectively, the o-DCB degradation efficiency reached approximately 100%. Under the same conditions, the CO2 yield was lower than the o-DCB degradation efficiency, indicating that the degradation of o-DCB was a multi-step reaction. The reaction kinetics showed that the kinetics of CO2 production in SCWO followed the pseudo-first order and the apparent activation energy was 172.4 kJ mol?1.