Research On The Continuous Detection Of Toc Based On Catalytic Supercritical Water Oxidation

A TOC detection device was set up by employing supercritical water oxidation (SCWO) as the oxidation method and nondispersive infrared analyzer (NDIR) as the detector of CO2. Effect of temperature, flow rate and H2O2 multiple on TOC detection rate were studied in the device with and without CuSO4 as catalyst. Meanwhile oxidation reaction kinetics of potassium hydrogen phthalate catalyzed by CUSO4 was studied under lower pressure. Potassium hydrogen phthalate and benzoic acid were used as model pollutants and H2O2 solution was used as the oxidant. Results showed that CuSO4 can effectively decrease the temperature and H2O2 multiple and ideal detection rates can be obtain under lower pressure. The optimum conditions for TOC detection were:T=420℃, P= 23.2 MPa, n= 3, and a flow rate of 2.0 mL/min. The activation energy and pre-exponential factor in the kinetics research was Ea= 61.54kJ-mol"1 and ko= 910.13s-1. Reaction orders for TOC and oxidant concentration were 1 and 0 respectively.Meanwhile, model wastewaters were prepared respectively with potassium hydrogen phthalate and benzoic acid and the accuracy of the SCWO-NDIR detector in TOC detection of those wastewaters were studied. Industrial wastewater from chemical engineering, pharmaceutical or dyeing company were also detected by Shimadzu TOC Analyzer and SCWO-NDIR detector. The relative errors were within ±5% and high accuracy can be obtained in the TOC detection of model wastewater.