|
(Boron-doped diamond, referred to as the BDD) electrode has a unique electrochemical characteristics such as low background current, a wide potential window of diamond film, chemically inert, corrosion resistance, etc., and make them suitable for the analysis of environmental pollutants, but also for the environment the degradation of contaminants. Based on its unique BDD electrode electrochemical advantages, has a chemical composition similar to the structure and nature of environmental pollutants is often difficult to separate the characteristics of multi-component complex system, to investigate the electrochemical behavior of multicomponent pollutants in the BDD electrode and its simultaneous determination will have important significance. This paper studies the multi-component organic pollutants, the BDD electrode electrochemical behavior of a variety of heavy metal ions in their interactions on the basis of cyclic voltammetry, differential pulse voltammetry, differential pulse stripping voltammetry other simultaneous determination of multiple electrical analysis method to explore the BDD electrode multi-component environmental pollutants direct electrochemical voltammetry method for separation and simultaneous determination of the feasibility of establishing multi-component environmental pollutants with a quick, easy, cheap, etc. The direct detection of the new method. BDD-based wide potential window characteristics, research BIOREFRACTORY the difficult oxidation typical aromatic molecules in the BDD electrode electrochemical oxidation of the feasibility and oxidation characteristics of the behavior, the direct electrochemical oxidation of BDD electrode degradation of aryl hydrocarbon pollutants laid a research foundation, has important theoretical significance. (1) multicomponent organic pollutants in the BDD electrode electrochemical behavior and simultaneous determination. Electrochemical method using cyclic voltammetry method (CV), differential pulse voltammetry (DPV) studied phenol, hydroquinone, nitrophenol the redox electrochemical behavior of BDD electrode; explore the multi-component phenolic compound in adsorption competition electrode; realized phenol - hydroquinone, phenol - nitrophenol, hydroquinone - nitro phenol, phenol - hydroquinone - nitrophenol and other multi-component organic pollutant the electrochemical separation; simple and sensitive method for the simultaneous determination of multi-component phenolic pollutants. (2) to study a variety of coexistence of heavy metal ions in the electrochemical behavior of BDD electrode, the establishment of a variety of heavy metal ions in the simultaneous determination of the experimental method. Heavy metal ions of silver ion, copper ion, lead ion and cadmium ion, stannous ion, cyclic voltammetry, differential pulse stripping voltammetry, electrochemical methods, nitric acid medium and acetate buffer solution medium to study single-ion system, a variety of ion composition of the mixed system in BDD electrode electrochemical redox behavior, study co-deposition of a variety of metal ions co-exist on the BDD electrode, interaction. Explore the feasibility of the separation of a variety of heavy metal ions in the BDD electrode electrochemical voltammetry, electrochemical simultaneous determination of a variety of heavy metal ions. (3) study the electrochemical oxidation of aromatic molecules of pollutants in the BDD electrode characteristics. Linear sweep voltammetry and differential pulse voltammetry, benzene, toluene, xylene, m-xylene, ethylbenzene five kinds of typical aromatic molecules to 0.5mol. L -1 sulfuric acid solution as the supporting electrolyte, five aromatic molecules the BDD electrode electrochemical oxidation behavior, timing power law aromatic molecules adsorbed on the BDD electrode, and constant potential the chronoamperometry further explore the mechanism of electrochemical oxidation of aromatic molecules. Cyclic voltammetry of the oxidation and reduction behavior of a variety of aromatic molecules on the BDD electrode was found, neither to the scanning process at the negative of the entire cyclic voltammetry reduction peak out generated, which indicates that the oxidation of the aromatic molecules on the BDD electrode The reaction is not reversible. Benzene, toluene, m-xylene, xylene, ethylbenzene oxidation number of peaks on the BDD electrode 2,3,3,3,4 aromatic molecular structure obtained in the different charge density, this result with the theoretical calculation H atoms of the type of number is just a difference of 1, the highest oxidation potential which happens to be located in the BDD electrode oxygen evolution potential (2.4V), presumably by the benzene ring oxidation open ring oxidation peak, while the lowest oxidation potential at the oxidation peak is almost equal to the oxidation of H atoms by the charge density on the benzene ring generated, while between the lowest oxidation potential, with the highest oxidation potential of a plurality of oxidation peak in turn there is a benzene ring substituted group-CH 2 - and-CH 3 on the oxidation of H atoms are closely related. Benzene ring having a substituent, and substituted group on the types of H more, the number of the oxidation peak of aromatic molecules in the BDD electrode is more, the lower the initial oxidation potential of the aromatic molecules, such as benzene, toluene, ethylbenzene, and the initial initial oxidation potential of the order of 1.91V, 1.75V, 1.67V; When the substituent on the benzene ring with the same substituent more aromatic molecules is more easily oxidized, such as xylene and toluene, the initial oxidation potentials were 1.63V 1.75V; the substitution position of the substituent is not substantially affect the oxidation properties, such as the initial xylene and meta-xylene oxidation potential of 1.63V and 1.64V. This is a very meaningful results. This show that the aromatic molecules can occur directly on the BDD electrode electrochemical oxidation, and in the different oxidation electrode potential, which can effectively control the degree of oxidation of the aromatic molecule and the oxidation product structure.
|