| In recent years, heavy metal pollution incident happens frequently, causing serious contamination to local water sources, posing a direct threat to people’s health. Most heavy metal detections are off-line, which can’t reflect real-time changes about water. To solve this problem, this subject developed a set of on-line detection for urban water supply system, which has a great significance to protect water quality. What’s more, this project is supported by 863 fund project- water treatment system based on WLAN.This paper analyzes the heavy metal detection methods that used nowadays at home and abroad. Then it discusses the advantages and disadvantages of these methods. Considering the practical inspection requirements, the anodic stripping voltammetry(ASV) becomes the appropriate choice. This system is divided into lower machine and PC software. EZ-USB FX2 microprocessor as the control center, combined with precision DAC, constant potential circuits, analog switches, I / V conversion circuit and ADC acquisition circuit, it can set the potential difference and detect the weak current between the working electrode and the reference electrode. The PC software controls the lower computer system operating orderly and auto-sampler collecting water samples directly. Then it uploads data, analysis and process for drawing current characteristic. Based on potential and current stripping peak, combined with a standard curve method, the type and concentration of heavy metal ions can be identified. Besides, the test results can be stored and printed.Finally, the system test results and their analysis show that the heavy metal detection system has many advantages: stability, high resolution, high-speed detection, wide linear range and low cost. What’s more, it can detect a variety of heavy metal elements and achieve online testing. |
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