Catalytic Supercritical Water Oxidation Treatment Of High Concentration Organic Wastewater

Catalytic supercritical water oxidation(CSCWO) which bases on SCWO is a promising technique for the treatment of organic wastes. The properties of supercritical water(SCW) were presented, the universal research works on the degradation efficiency, oxidation kinetics and reaction pathway of organic pollutant were reviewed, and the characteristics of CSCWO were discussed in this paper.The homogeneous and inhomogeneous catalyzed oxidation of acetic acid -, hydroxy-naphthalenesulfonic acid and amino-naphthalenesulfonic acid in SCW were studied under the different conditions. The result showed that the organic pollutants could be effectively destroyed by CSCWO; The COD removal rate of organic pollutants would increase with the increment of reaction temperature, residence time, concentration of catalysts and with appropriate catalysts, among which using appropriate catalysts was the main factor effecting the COD removal rate of organic pollutants. Reaction temperature, residence time had also primary influence on the oxidative decomposition of organic pollutants.It was found that catalysts existed in the form of deposition in homogeneous catalyzed oxidation, so we could use the following model to explain the dissolution of catalysts:MyXz(s) + rH2O = MyXz-rH20 (sup)In this paper, the kinetics of oxidative degradation of acetic acid and hydroxy-naphthalenesulfonic acid in SCW were studied systematically. The results were as follows:The CSCWO products of hydroxy-naphthalenesulfonic acid were analyzed and identified systematically by GC-MS. The following model could be used to show the oxidative degradation pathway of the organic pollutants in SCW :The application prospect and engineering problems were discussed deeply. The higher efficiency of treatment could be achieved by using appropriate catalysts. Corrosion could be resolved or alleviated by proper choice of corrosion-resistance material. The energy self-sufficiency can be realized by reasonable design of reactor structure and technology.