2004 Volume 83 Issue 4 Pages 281-284
For the purpose of establishing recycle technology to reduce environmental load, technical and practical development of supercritical water (SCW) is required. That is non-catalytic hydrolysis expected to develop.SCW has some advantages in chemical processes. SCW can form a homogeneous phase with oil and gas and in addition, changing the conditions of SCW can be used to control equilibrium and reaction without catalyst.
Dithionic acid, which is difficulty to decompose, is a Chemical Oxygen Demand waste generated during desulfurization. Experiments were conducted to hydrolyze ditionic acid in SCW. In the experiments, it was found that decomposition rate of dithionic acid was the same regardless of whether hydrogen peroxide was added or not. Dithionic acid occurred at 100% conversion at 350°C. The sulfuric acid ion/sulfurous acid ion concentration ratio increased with increasing the amount of hydrogen peroxide. Activation energy for decomposition of ditionic acid in SCW under non-catalytic conditions was determined to be 39kcal/mol and was slightly higher than activation energy of the catalytic reaction.
