对氯苯酚超临界水脱氯的反应动力学及机理分析

he supercritical water oxidation (SCWO) dechlorination kinetics and mechanism of p-chlorophenol (4-CP) was studied in an isothermal and vertical plug-flow reactor at 400-460℃, 24 MPa, residence time of 30--200 s, and excess oxygen of 100%-500%. The results showed that the dechlorination rate of 4-CP could reached 80% at 440℃, 24 MPa and excess H2O2 375%. The dechlorination rate increased with the increase in the temperature and residence time, while it did not obviously change by the initial concentration of 4-CP and excess H2O2. It was found that kinetics for dechlorination of 4-CP was described by a rate law involving first order reaction of 4-CP, zero order reaction of H2O2, 92.978 KJomol-1 of activation energy, and 104.6302 of Arrhensius pre-exponential factors. The experimental results were forecasted well by the kinetics equation through repeated experiments. The results of GC/MS analysis showed that hydroquinone, catechol and benzene hydroquinone were the major intermediates and the reaction process included the coupling of free radicals. The research revealed the dechlorination process and mechanism of 4-CP in supercritical water and was expected to provide the basis for the engineering application of SCWO technology.