Analysis of brines for the content of the main substance and impurities of magnesium and calcium salts by the sonoluminescence method

Abstract

The use of the sonoluminescence method for the analysis of brines for the content of the main substance – sodium chloride and admixtures of magnesium and calcium salts – was studied. The use of sonoluminescence initiated by the ultra-high frequency ultrasound (10.0–25.0 MHz) to determine the content of the main substance – sodium chloride – in brines, as well as sonoluminescence initiated by the simultaneous action of ultra-high- (10.0–25.0 MHz) and low- (20–100 kHz) frequency ultrasound to determine the content of magnesium and calcium salts was experimentally investigated. When determining the content of sodium chloride in brines, the smallest relative standard deviation of the analysis results (Sr = 0.010–0.013) was when using the ultra-high-frequency ultrasound with a frequency of 22.0–23.0 MHz and intensity of 20.0 W/cm2. When determining the content of magnesium and calcium salts, for the initiation of sonoluminescence, it was optimal to use the simultaneous action of ultra-high frequency ultrasound (20.0–22.0 MHz) and intensity (20.0 W/cm2), and low-frequency ultrasound (19.0–22.0 kHz) and intensity 1.30–1.50 W/cm2, which made it possible to increase the sensitivity of determining magnesium and calcium in brines from 3.0–5.0 g/l when initializing sonoluminescence by the low-frequency ultrasound to 0.01 g/l when initializing sonoluminescence by the simultaneous action of ultra-high- and low-frequency ultrasound.
 Methods for determining the content of the main substance and impurities of magnesium and calcium salts in brines have been developed. The correctness of the methods was checked by analysing the same samples using alternative methods. When determining the content of the main substance, the following methods were used as alternative ones: gravimetry and the sonoluminescence method of low-frequency ultrasound, as well as with high-frequency ultrasound. When determining the content of magnesium and calcium salts, flame atomic absorption spectrometry and the sonoluminescence method of low-frequency ultrasound, as well as with the simultaneous action of high- and low-frequency ultrasound, were used as alternative methods.