Abstract:Arsenic is a highly toxic substance, and it is of great significance to establish a method for the determination of arsenic in industrial wastewater from copper smelting. The contents of salts such as copper, iron and zinc in industrial wastewater of copper smelting are high, and meanwhile, the matrix is complex. During the determination by atomic fluorescence spectrometry in HJ 694-2014, the sample will pollute the instrument pipeline and block the atomizer. Moreover, there is memory effect. In this study, the sample was digested with hydrochloric acid and nitric acid in water bath at 80 ℃. Arsenic in sample was separated and enriched by lanthanum hydroxide co-precipitation method. Then the precipitate was dissolved with hydrochloric acid. The method for the determination of arsenic in industrial wastewater of copper smelting by precipitation separation hydride generation atomic fluorescence spectrometry (HG-AFS) was established. The problems of instrument pipeline pollution, atomizer blocking and memory effect were solved. The results showed that the mass concentration of arsenic in range of 2.0-10.0 μg/L had linear relationship with the corresponding fluorescence intensity. The correlation coefficient was 0.999 8, and the limit of detection of method was 0.027 μg/L. The interference tests showed that the coexisting elements in sample had no interference with the determination. The proposed method was applied for the determination of arsenic content in three wastewater samples from copper smelting. Moreover, the standard addition tests were conducted for five times. The relative standard deviations (RSD, n=5) of the measured results were 2.0%-3.6%, and the recoveries were 97%-108%. Arsenic in wastewater samples of copper smelting was determined after precipitation separation according to the experimental method, and the measured results were basically consistent with those obtained by standard HJ 694-2014.
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