Studies On Electrochemical Detection Of Harmful Pollutants Into Water

In recent years, the incident of heavy metal pollution occurs frequently as an increasingly prominent environmental pollution problem. Thus, before controlling the heavy metal pollution, the precise identification and detection of trace heavy metal ions in environmental samples are essential. The method of electrochemical analysis is becoming a research focus for it can meet the need of live, continuous and online detection, in which the key is the development of high sensitivity, harmless, inexpensive working electrode. This paper aims to study the detection of heavy metals in the water environment with titanium metal as the working electrode material by anodic stripping voltammetry.(1) The Ti/TiO2 electrode was prepared by thermal oxidation with Titanium plate as electrode substrate. To explore its electrochemical performance in the detection of lead and cadmium into water, the Ti/TiO2 electrode was used as working electrode with differential pulse voltammetry. The influence of preparation conditions(temperature and time) upon the performance of the Ti/TiO2 electrode was investigated. The experimental parameters of electrochemical workstation was optimized through the experiment. And it realized simultaneously detection of heavy metal ions(Pb2+ and Cd2+) under the optimum conditions. While the sensitive of detection is well, which indicated the prepared Ti / TiO2 electrode can be used for the detection of Pb2+ and Cd2+of low concentrations.(2) The detection of heavy metals(Pb2+ and Cd2+) with the bismuth film electrode by differential pulse stripping voltammetry was studied. With the Ti/TiO2 electrode as the electrode substrate, the Bi-Ti/TiO2 electrode was prepared through the measure of pre-plated bismuth films. The effect of deposition time of bismuth film upon the detection was investigated. And fulfill the detection of heavy metal ions(Pb2+ and Cd2+) into water respectively with the use of Bi-Ti/TiO2 electrode. The experimental results showed that the Bi-Ti/TiO2 electrode can significantly improve response sensitivity of Pb2+ and Cd2+. And the current of stripping peak showed a good linear relationship with the concentration of heavy metals(Pb2+ and Cd2+) respectively in a certain range.(3) A novel method of anodic stripping voltammetry to detect heavy metal ions based on the photoelectric effect was studied, in which using photo-deposition instead of traditional electrochemical deposition for the preconcentration of heavy metal ions, then dissolved by differential pulse stripping voltammetry. Experiments found that under UV irradiation, Ti and Ti/TiO2 electrode can significantly improve the sensitivity of detection of heavy metal ions, And Ti /TiO2 electrode can selectively detect heavy metal ions by adjusting the conduction band edge of electrode. Finally,Heavy metal ions(Pb2+, Cd2+, and Cu2+) were detected simultaneously with Ti/TiO2 electrode, and the current of stripping peak showed a good linear relationship with the concentration of heavy metals(Pb2+ and Cd2+) respectively in a certain range(0.8 ~ 1.6mg / L), for which can be applied for the detection of low concentrations of heavy metal ions.