| The heavy metal pollution is a major source of water pollution, and the management and the separation of heavy metals have become one of the important studied issues of today's environmental science. So the reliable measurement of trace metal ions in natural water is very important for pollution and the recovery of trace elements, However, the distribution of the trace chemical components often changes in the process of sampling and storage, and most environmental measurement is continuous, rapid, trace and ultra trace analysis, the samples are mostly complex components so the reliable measurement is not easy.The diffusive gradients in thin-films technique (DGT) incorporates an ion-exchange resin separated from the solution by an ion-premeable gel membrane and controls the ion exchange in order to obtain quantitative analytical data in situ. This technology provides a new method for quantitative and in-situ measurement of certain substances in the aqueous solution system, and combines the accumulating and the sampling, so this technique is very simple and fit for the measurement of trace metal ion in the water. In this paper the polyethylene alcohol is used to do the binding layer and cellulose acetate dialysis membranes are used to do the diffusive layer to realize the excellent selectivity of Cu2+ in solution.This paper studies the excellent selectivity of Cu2+ when other heavy metal ions coexist in solution and the selectivity of Cu2+ under different interference conditions, such as the impact of different pH, ionic strength and nonselective matter, together with the competition and noncompetition experiment. Experiment show that the conditions have no clear interference with the selectivity, and the scope for acidity is appropriate. Also studied the complex constants, diffusion coefficient of the liquid phase (PVA) and Cu2+ expand this study to practical application, realize the determination of Cu2+ in natural water. |
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