Research and Application on Dynamic Test of Solution Concentration
|School||Nanjing University of Posts and Telecommunications|
|Course||Measuring Technology and Instrument|
|Keywords||Electrochemical impedance spectroscopy Dynamic measurement Differential element System identification|
Electrochemical impedance spectroscopy technique is a very important research method of electrochemical measurement techniques, the research and application of static impedance spectroscopy technology have been done for many years both in domestic and abroad. But there are no reports in the dynamic impedance spectroscopy technology. The impedance spectrum technique is applied to the measurement of solution concentration. Combined with the differential element method, a electrochemical analysis system is designed which realizes the dynamic measurement of solution concentration. Based on the analysis of sucrose hydrolysis experiment, dynamic equation of sucrose hydrolysis has been achieved. The innovation of this paper are as follows:(1) Differential element method is introduced to impedance spectroscopy techniques, combined with the theory of system identification, the dynamic measurement of solution concentration is achieved.(2) According to the Nyquist, the model of the system can be simplified when choosing the suitable frequency range, then the capacitance is obtained.(3) Research the sucrose hydrolysis by capacitance instead of optical rotation. Using capacitance simplify the measurement. The sucrose hydrolysis can be dynamic observed and the equation of sucrose hydrolysis is obtained.The system output different signals based on the PXI-6070E data acquisition card. At the same time, PC collects the signal of chemical reactor. Combined with the impedance measurements, measure and analyze the model and parameters of the system by frequency domain and time domain. The system model is simplified and the capacitance is obtained. Sucrose is the research object, firstly, do the research of sucrose dissolution, the dynamic measurement is achieved. Then, research and analyze sucrose hydrolysis which is the typical dynamic process. The reaction order and rate can be obtained. The result provides a basis for the study of reaction mechanism and rate law, having a far-reaching research value.