Abstract
Supercritical water oxidation (SCWO) is an attractive alternative mean for treatment of organic wastes of high water contents. However, for most of organic compounds, acetic acid is a stable intermediate product, and a high reaction temperature or catalyst is required for its complete decomposition.
In this study, a new method of utilization, rather than decomposition, of residual acetic acid produced by supercritical water oxidation of beef suet was investigated. That is, the residual acetic acid was converted into (CH3COO)2Ca, which can be used as a deicer to reduce environmental pollution problems caused by the road deicing salts (NaCl and CaCl2) presently available.
Results showed that acetic acid of high concentration (6,000 mg / l) and relatively high purity was obtained under the condition of 400 °C of reaction temperature, 30 seconds of reaction time and 150 % of H2O2 supply, and 97 % of residual acetic acid was covered to (CH3COO) 2Ca by adding Ca(OH)2 or CaCO3 in the both cases of its addition before and after the oxidation reaction. However, in the former case, when excess Ca(OH)2 or CaCO 3 was added, some products by thermal decomposition and hydrolysis appeared, and production of acetic acid decreased.
