Study Of Electrochemical Determination Of Heavy Metal Ions Via Non-mercury

With the enlargement of cities and development of industrialization, life sewage and industry waste water are drained into water environment. Heavy metal entering into water environment are severely endangering human health through drinking water, bioconcentration and food chain etc. Therefore quantitative analysis of trace heavy metal is extremely important in water environment monitoring. This paper, relying on the Ministry of land and Resources public industry research and development of special project "typical metal mine groundwater environmental monitoring technology research", dedicated to the study of environment friendly without mercury electrode electrochemical detection of heavy metal ions in water, and the development of a real-time monitoring system for heavy metal ions. The main research works are as follows:The trace, As, Sb and Pb in groundwater of mines in leng-shuijiang was simultaneously determined by using the gold electrode as the working electrode. The influences of the working electrode, pre-deposition time and supporting electrolytes on the determination of heavy metal ions were investigated. It was found that the electrochemically pretreated gold may be more appropriate for the simultaneous determination of As, Sb and Pb than the mechanically treated gold electrode. Under the optimum condition, it was obtained that the peak potentials were0.18v,0.18v,-0.07v for As3+, Sb3+, Pb2+at the gold electrode. The peak currents changed linearly with the concentration and the detection limits were0.5μg/L,5μg/L and2μg/L. This proposed method was simple, minimum interference, wide linear range, high sensitivity.Based on bismuth-film electrode, zinc, cadmium, lead and copper are simultaneously detected by stripping voltammetry, avoiding environmental pollution caused by the use of mercury electrode. Zinc, cadmium, lead, copper and bismuth form an alloy of similarly amalgam in the process of concentration, with a good stripping peak. A series of experiments have been carried out to obtain optimized parameters, discussing the concentration time, enrichment potential, supporting solution, the pH of supporting solution.In the optimized experimental conditions, the trace heavy metals of zinc, cadmium, lead, and copper are measured at the same time, The concentrations of detection reach the standards of 《health standards of drinking water》(GB5749-85), and some are even lower. Their linear ranges are respectively20～100μg/L,5～50μg/L,5～50μg/L and20～100μg/LProceed to study the real-time online monitoring of heavy metal ions system on the basis of the above electrochemical analysis. According to the sample properties, electrochemical determination conditions, geographical features, complete respectively the system of water sample pretreatment unit, control unit, detection unit and the communication unit hardware design; then according to the idea of modularization, using the C language programming, complete the design of system software. Finally, successfully developed to automatical monitor for online monitoring of water quality heavy metal, and applied to the actual waters samples.