Experimental And Theoretical Study Of Acrylonitrile Wastewater In Supercritical Water

Supercritical water oxidation?SCWO? is an effective treatment technology for a water-based organic waste, is the sustainable development of green technology. After nearly 30 years, both on the basis of theory and practical application have made no small progress. In the petrochemical industry, materials science, bioengineering, environmental pollution and other areas have been addressed to varying degrees of application, such as organic sewage, municipal waste sludge and chemical weapons and the like.According to the conditions and principles of supercritical water oxidation technology, acrylonitrile wastewater as the research object in this paper. Using independent design assembled a continuous supercritical equipment by the group to research and discussion. During the experiment which leads to peracetic factor of 2, the reaction temperature range of 460⁵35?, reaction pressure in the range of 17²5 MPa, the initial concentration in the 0.5² g/L, reaction residence time between 60 s and 180 s. Changing a single variable, then the value of the effluent COD was measured by potassium dichromate method, discussing the impact of changing the reaction conditions for the purification efficiency.The results show that as the temperature, pressure, and acrylonitrile's initial concentration reaction increasing, the value of CODcr is decreasing. Then making the purification efficiency with changing conditions of each reaction curve. It is found that closer to the upper limit of the reaction conditions set area, the more flatten. Indicating that the acrylonitrile wastewater is oxidized completely. Suitable reaction conditions are obtained: temperature is 505?, pressure is 23 MPa, initial concentration is 1 g/L, residence time is 120 s. Under the reaction conditions, the reaction of acrylonitrile in the process of supercritical water oxidation kinetics was studied. After fitting experimental data and computational determination, the value of reaction rate constant k is 0.0648 s-1. And draw their macroscopic kinetic equation:Finally, according to the perspective of quantum chemistry theory, used density functional theory B3 LYP method to calculate the optimize the structure of C₃H₃ N and H2 O. And analyzed their oxygen radical anion channel comprises hydrogen abstraction reaction, substitution reaction of hydrogen and generate water reaction. Determined the presence of the reaction channel is reasonable. And added in the direction of electric field calculation command to carbon-carbon single bond is z-axis, the field size increased from-100 to +100, and simulate the interaction between C₃H₃ N and hydroxyl in the supercritical state. The results showed that with increasing electric field strength, the interaction reduced. The transition state be more unstable. It is indicating that to add electric field on negative direction of z-axis can be in favor of the reaction.