CMC-a New Liquid Binding Phase For Accumulation And Measurement Of Trace Copper, Cadmium, Zinc In Water By Diffusive Gradient In Thin Film Technique

Metals which specific gravities are larger than 5.0 or equal to 5.0 are heavy metals. Heavy metals can't be decomposed by organism. On the contrary, organism can enrich them and transfer them to metal-organic compound which have more toxicity. Because of that, heavy metals are one of latent contamination. Along with development of industrial of plating and dye matter, more and more waste water consisted of heavy metal ions is let out. As result, the health being and the security of environment are in danger. Scholars made abroad and in-depth research on the chemical characters of heavy metal ions in water. In all those studies, analysis of heavy metals is basic research.Due to low content of heavy metal ions in water, and complicated speciation, every group has influence on different checking method. A lot of instrument analysis, such an Emission spectrometry and polarograph, has not enough sensitivity. Even if it can check those low consistence elements, basic element has infection on exactitude and precision of the checking method. Therefore accumulation and sampling the trace heavy metal ions from basic element are necessary.The diffusive gradient in thin-films technique (DGT) incorporates an ion-exchange resin separated from the solution by a gel membrane and controls the ions exchange in order to obtain quantitative analytical data in situ. This technique is not only overcoming the difficulty of the pretreatment but also combining the enrichment and sampling. So the technique is very simple and fit for the measurement of trace metal ion in water. Carboxymethyl cellulose is used to be the liquid binding layer and cellulose acetate dialysis membranes are used to be the diffusive layer in this work. And the concentration of Cu2+, Cd2+, Zn2+ is determined in the synthetic solution. Not only Carboxymethyl cellulose is cheap in price, but also it can decompose by itself, so it is a kind of economical and nontoxic binding phase.In this thesis, it was studied that binding condition and binding mechanism of carboxymethyl cellulose in solution, including effect of deploy time, temperature, acidity, ionic strength on binding of heavy metals, and it is ensured the appropriate binding phase concentration. Concentrations of Cu2+, Cd2+, Zn2+ are measured in known concentration synthetic solution by diffusive gradients in thin films technique. In order to improve veracity, diffusive boundary layer thickness is estimate. Due to organic ligands contained in natural water, they have effect on diffusive of heavy metals, so it is discussed binding capability of DGT sampler in solution comprising of fulvic acid. In the laboratory condition, diffusive gradients in thin films technique is applied in tap water and south lake water.From the experiment, we can draw the conclusion that, diffusive gradient in thin film technique with a liquid binding can be used for measurement of trace labile metal in water. This technique has many excellences, such as simple equipment, convenient manipulation, broad extent, et al. Carboxymethyl cellulose is one kind of good liquid binding. It could accumulate heavy metal ions in water, and it enriches those ions in large multiple and fast speed. Besides, carboxymethyl cellulose is one kind of green material used in analysis.