Electrochemical Control of Microconcentrations of Cadmium in Aquatic Environments

Autor: V. A. Kopilevich, R. V. Lavrik, I. V. Surovtsev, V. I. Maksin, V. M. Galimova
Rok vydání: 2021
Předmět:
Zdroj: Journal of Water Chemistry and Technology. 43:336-341
ISSN: 1934-936X
1063-455X
Popis: Cadmium has a carcinogenic effect with a pronounced cumulative action on humans and animals and belongs to the most dangerous water pollutants, as a result of which it is classified as a nutrient that must be controlled. Electrochemical methods of analysis are the simplest ones to operate, and highly sensitive and accessible for ecological control and measurement of cadmium ions in water. A method for measuring microconcentrations of cadmium in natural drinking water from water supplies, in surface water from lakes and wells, and in aqueous solutions by inverse chronopotentiometry (ICP) with high repeatability and accuracy in accordance with the criteria of metrological certification is developed in this study. The essence of the ICP method is the electrochemical concentration of the element from the sample solution on the indicator electrode with subsequent measurement of its dissolution potentials in time (inversion) at a given resistance in the oxidation circuit. The cadmium content in the samples is determined by the method of addition of a standard sample with a known weight of cadmium ions. It is established that the limit of absolute error in the measurement of cadmium concentrations CCd does not exceed ±0.2CCd, and the relative error of measurements ranges from 1.54 to 15.2% depending on the concentration. According to the developed method, the lower limit of determination of Cd is set at 0.1 μg/dm3. The appropriate level of proximity of the results of cadmium concentration determinations by the developed electrochemical method of analysis and the atomic absorption spectrometric (AAS) method with electrothermal atomization is found in different samples of drinking water and aqueous solutions. The correctness of determination of Cd is evaluated by the dilution ratio method and the method of additions of certain amounts of a standard cadmium salt solution sample. The results of measurements of Cd content in drinking water from wells and surface water samples of lakes of the Kyiv oblast indicate an appropriate level of coincidence of concentration values, as well as suitability of the sample preparation and electrochemical parameters for determining the content of metal ions. The developed method of determination of cadmium by the method of inversion chronopotentiometry allows one to maintain reliable ecological control of its content in water samples of different natural origin in the range from 0.1 to 100 μg/dm3, which corresponds to the regulated concentrations for water sources.
Databáze: OpenAIRE
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