The Research On Kinetic Process Of Complicated Reaction With Reactive Intermediates

Cr (VI) is known as one of major environmental pollutants, which is harmful to human body. Vitamin C is a nontoxic bio-reductant, which can be effectively used in Cr (VI) disposal. Therefore, the kinetic investigation of reaction between them is meanful to the normal life and industrial application. In this work, the online kinetic-spectral data from this reaction is used to carry out the research. But the fact that two reactive intermediates Cr (V/IV) exist in the reducting process makes the mechanism inexplicable so far and the data resolving process not so easy. Model free methods, which based on general assumptions such as non-negativity of spectra and concentration profiles, show advantageous to this reaction. However, some new problems float onto the surface during their application to the calculating process. The findings of two absorptive reactants and their hardly detected selective wavelength make the results from general model free methods not reliable. Therefore, in the work, a method named component annihilation and its iterative process are suggested to be combined with general model free methods to annihilate the information of spectrum-known component. Thus, the data matrix can be simplified so that the further mining of the kinetic information can be realized. Two parts are mainly involved in this work. In the former part, specific procedures of mentioned methods are explained. Afterwards, three groups of simulated data were used to explain the application of mentioned methods and reliable results were achieved. The model free methods used here are Needle Search and Iterative Target Transformation Factor Analysis (ITTFA) . In the latter one, experimental data was investigated. Based on the results of simulated data, each reactant concentration profile is figured out respectively. Moreover, non-scaled concentration profiles (with the maximum of 1) of intermediates Cr (IV/V) are resolved. Futhermore, the mechanism of this reaction is discussed based upon the resolved kinetic process.