SU1576852A1 - Method of concentrating lead, copper and cadimium from solutions - Google Patents

Abstract

The invention relates to methods for concentrating lead, copper and cadmium from water and sodium chloride solutions for their subsequent analytical determination by an atomic absorption method involving their coprecipitation with a collector of a mixture of magnesium hydroxide and calcium carbonate in the ratio of 1: (4-5) when exposed to ultrasonic oscillations of frequencies 18-24 kHz with an intensity of 1.4-2.5 W / cm 2 for 20-25 s. The degree of coprecipitation is 99%, the detection sensitivity is 0.75 .10 -6 µg / l of lead, 0.15 .10 -6 µg / l of copper, 0.04 .10 -6 µg / l of copper. The time of preparation of the concentrate is less than 1 hour. f-ly, 6 tab.

Description

The invention relates to the field of analytical chemistry. It can be used to determine the impurities of lead, copper and cadmium in natural water, as well as in salt solutions.

The aim of the invention is to increase the degree of concentration and acceleration of the process.

Example 1. Determination of lead, copper and cadmium in water.

1000 ml of the water to be analyzed are placed into 1500 ml beakers, 0.1 mmol of magnesium sulfate and 0.5 mmol of calcium chloride are introduced, sodium carbonate and sodium hydroxide are added to a pH of 14 and subjected to 18 kHz ultrasonic (UL) vibrations, intensity of 2.0 W / cm2 for 20 s. The precipitate is allowed to settle, a clear liquid is siphoned, and the remaining part of the solution is separated from the precipitate by centrifugation. The precipitate is dissolved in hydrochloric acid and the content of lead, copper, and cadmium is determined by an atomic absorption method.

1.46 μg / l of lead (1.5 μg / l were introduced), 1.48 μg / l of copper (1.5 μg / l were introduced), 1.57 μg / l cadmium (1.5 μg were introduced / l)

1.32 μg / l of lead, 1.21 μg / l of copper, 1.21 μg / l of cadmium were detected by a known method.

PRI mme R 2. Analysis of an artificial solution of salt.

200 g of sodium chloride (chemically pure) are placed in 1500 ml beakers, dissolved in distilled

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about

00

ate

Yu

“%.

water and analyzed as described in example 1.

About 1 mmol of magnesium sulfate and 0.4 mmol of calcium chloride are added for coprecipitation, sodium carbonate and sodium hydroxide are added to a pH of 12.5.

Ultrasonic vibrations are used at a frequency of 24 kHz, an intensity of 1.4 W / cm2 for 25 s.

4.96 μg / l of pig, 4.91 μg / l of copper, 4.95 μg / l of cadmium were found in the solution. In a known manner, 4.57 μg / l of lead, 4.52 μg / l of copper, 4.06 μg / l of cadmium were detected (5.0 μg / l of lead, copper and cadmium were added).

EXAMPLE 3 An analysis of a solution containing 100 g of sodium chloride is carried out as described in Example 1. 0.1 mmol of magnesium sulfate and 0.45 mmol of calcium chloride are added to precipitate, sodium carbonate and sodium hydroxide are added to a pH of 13. .

The frequency of ultrasonic vibrations of 20 kHz, the intensity of 2.5 W / cm2 for 22 s.

2.98 µg / l of lead, 3.03 µg / l of copper, µg / l of cadmium were found in the solution. 3.30 µg / l of lead, 2.71 µg / l of copper, 2.43 µg / l of cadmium (3.0 µg / l of each metal were introduced by a known method).

Table 1 presents the comparative data of the known and described methods.

Table 2 presents data on the effect of the number of collectors and the corresponding

five

0

five

0

five

Carrying magnesium hydroxide and calcium carbonate in the reservoir.

Table 3 presents data on the effect of ultrasonic vibrations on the coprecipitation of lead, copper and cadmium.

Table 4 presents data on the effect of the frequency of ultrasonic vibrations on the degree of coprecipitation.

Table 5 presents data on the effect of the intensity of ultrasonic vibrations on the degree of coprecipitation.

Table 6 presents data on the effect of the time of exposure of ultrasound on the degree of coprecipitation.

Claims (2)

1. Lead concentration method copper and cadmium from solutions, including their coprecipitation with a calcium carbonate collector, for subsequent analytical determination by an atomic absorption method, characterized in that, in order to increase the degree of concentration and acceleration of the process, magnesium hydroxide is additionally introduced at a molar ratio with carbonate calcium 1: (4-5), and coprecipitation is carried out when exposed to ultrasonic vibrations. 2. Method pop. 1, characterized in that ultrasonic vibrations with a frequency of 1824 kHz and an intensity of 1.4-2.5 W / cm are used for 20-25 seconds. Table 1 97.4 89.0 99.3 90.3 81.3 99.0 37.8 14.6 98.7 3.7 - 96.4 50.8 - 1.0 99.4 99.6 98.7 97.6 96.3 200 1.5 0.3 1,5-Ю-5 0, 3.8 16.4 0.15 0.8 0.15-10 ° 0.75 2.8A, 62.2 10,817,23,6 2.0 - 2.5 РЪ I Si I Cd | Rb | Cd Pb C J Cd J Pb I C Fed G Pb | Si led Note. The averaged data from six experiments are presented: sample solution of sodium chloride solution 1000 sludge, sodium chloride concentration 150 g / l; lead, copper and cadmium were introduced at 3.5 µg / l, ultrasound frequency (US) was 22 kHz; ultrasound intensity of 2.5 W / cm1; ultrasound exposure time 20 s. Table3 ,eight ABOUT 100 150 200 250 74,676,6 47.447.6 21,427,6 11,812,3 Continuation of table 1 1000 0.15 0.8 0.2 0.08 , -6 0.15.10 ° 0.04-10 , -6 1,51,3 2.92.4 0.8 - 1.0 Table2 99.1 99.0 98.5 96.0 81.1 99.2 98.4 98.0 95.3 82.3 99.4 98.5 97.6 95.9 80.0 Note. The averaged data of six experiments are presented: 3.5 μg / l of lead, copper and cadmium are introduced} the volume of the analyzed solution is 1000 ml, the pH of the solution is 12, the frequency of the ultrasound is 22 kHz and the intensity of the ultrasound is 2.5 W / cm2; agitation time (when analyzed without exposure to ultrasound) 10 min. TableA the The averaged data of six experiments are presented: the volume of the analyzed solution is 1000 ml1, the concentration of NaCl is 150 g / l; the amount of Pb, Cu, Cd introduced is 3.5 µg / l; ultrasound intensity of 2.5 W / cm2; the time of exposure to ultrasound 20 s, the pH of the solution is 12. Continuation of table 3 Note. The averaged data from six experiments are presented: the volume of the analyzed solution is 1000 ml {sodium chloride concentration 150 g / l; the number of injected Pb, Cu, Cd at 3.5 µg / l; ultrasound frequency of 2.5 W / cm2; ultrasound exposure time 20 s; pH of 12. Table Note. Presents the averaged data of six experiments: the volume of the analyzed solution is 1000 ml; sodium chloride concentration of 150 g / l; the number of Pb, Cu, Cd administered at 3.5 µg / l; ultrasonic frequency of 2.5 W / cm2; pH of 12. Compiled by T.Zhukova Editor L.Gratillo Tehred L.Serdgakova Proofreader E.Lonchakova Order 1844 Circulation 502 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, Ul. Gagarin, 101 1576852 10 Table 3 Subscription