RU1834704C - Method of composition sorbent uneks-c production on base of natural clays - Google Patents

Abstract

Usage: purification of solutions of transition metal ions and radionuclides. The inventive method for producing a composite sorbent by chemically modifying natural clay in two stages: in the first stage, carried out before heat treatment, the modification is carried out by a reagent from the group: phosphoric acid, sodium silicate or NzRO4 and aluminum salt, or NzRO and sodium silicate, or НзР04, sodium silicate and aluminum salt in an amount of 1-10 mmol per 1 g of clay, and in the second stage, the modification is carried out with a reagent selected from the group: antimony, titanium or zirconium oxide, titanium or zirconium phosphate, or ferroc transition metal anide at the rate of 0.12 mmol per 1 g of clay. 6 zpp-fs, 2 tab.

Description

The invention relates to methods for producing sorbents with high sorption affinity for metal cations, which makes them promising materials for the selective extraction of heavy metal ions, radionuclides from solutions of complex composition, as well as for deep purification of drinking water.

The aim of the invention is to develop a method for producing a sorbent based on natural clays with increased selectivity for metal cations, which will allow it to be used for the selective extraction of metal ions, as well as cesium and strontium radionuclides from solutions of complex composition and for deep purification of drinking water.

The goal is achieved by chemical modification of natural

clay in two stages: in the first stage, carried out for heat treatment, the modification is carried out by a reagent from the group: phosphoric acid, sodium silicate or phosphoric acid and aluminum salt, or sodium silicate, or NZRO, sodium silicate and aluminum salt, in the amount of 1 -10 mmol per 1 g of clay, and in the second stage, the modification is carried out by the selected reagent and the groups: antimony, titanium or zirconium oxides, titanium or zirconium phosphates, or transition metal ferrocyanides, based on 0.1-2 mmol per 1 g clay.

A distinctive feature of the method is that the heat treatment of the modified clay is carried out at a temperature of 300-600 ° C.

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Another difference of the method is that the introduction of transition metal ferrocyanide is carried out by sequential treatment with potassium ferrocyanide and a transition metal salt,

Another difference of the method is that the antimony, titanium or zirconium oxides are introduced by treating the clay with water-soluble salts of antimony, titanium or zirconium, followed by their hydrolysis.

Another difference of the method is that titanium or zirconium phosphate is introduced by sequentially treating the clay with a water-soluble salt of zirconium titanium and orthphosphoric acid or alkali metal phosphate.

The advantage of carrying out the chemical modification in two steps before and. after heat treatment of clay and the use of a reagent or a combination of reagents from the NzRSm group at the first stage, aluminum salt, sodium silicate provides the most effective activation of the material structure (developed porosity, aluminum enrichment, the appearance of phosphate functional groups), and modification at the second stage with reagents from the oxide group or phosphates of polyvalent metals, transition metal ferrocyiaides gives composite sorbents increased affinity and provides selectivity to α-metal ions c, radionuclides of cesium, strontium, ce. ri.

Heat treatment of modified clay at a temperature of 300-600 ° C intensifies the course of activation processes, and also gives the material the necessary mechanical strength.

The ratio and amount of modifying reagents were selected experimentally, which allows to achieve the maximum positive effect of increasing the selectivity of composite sorbents to cations.

The proposed technology allows to obtain selective sorbents that can be used for the selective extraction of α-metals and radionuclides from solutions of complex composition, as well as drinking water. The resulting composite sorbents are characterized by low cost, non-toxic, high kinetic properties and can be used in household filters for drinking water purification. Example 1. To 100 g of finely ground natural clay (marl) placed in a 1 L glass reactor equipped with a stirrer, 100 ml of a 3 M solution of NzROl were added and stirred 30 minutes until the reaction was completed, then the clay was separated from the solution and heat treated with T 350 ° C. The calcined material is treated with 500 ml of a 0.2 M solution of potassium ferrocyanide, and then 250 ml of a 0.8 M solution of copper sulfate. After that, the sample is washed with water and dried in air.

The results of testing the sorption properties of the modified clay are shown in Table 2 (ex, 1).

P r and m e r 2, All operations are similar

given in Example 1. The types of clays, as well as the reagents used to modify them, and their amounts are given in Table 1 (Ex. 2-5). The test results of the sorption properties of composite sorbents are presented in Table 2 (Ex. 2-5).

The sorption capacity of the samples was determined from 0.1 N. solutions of lead and copper acetates at T: W 1: 100. Distribution coefficients were determined from Ringer's solution having a radionuclide activity of 1-2 x Ci / L at T: W 1: 200.

The sorbent prepared by the prototype method, under similar conditions, exhibits the following sorption indicators: Pb capacity - 0.6 mg-zqq / r, 0.35 mEq / g each, KdCs -250, KdSr-120 significantly inferior to those of composite sorbents based on natural clays.

Please name this sorbent: UNEKS-C (universal inorganic composite clay sorbent).

Formulas of the invention

Claims (7)

1. A method for producing a composite sorbent based on natural clays, including their chemical and thermal modification, washing and drying, and only so that, in order to increase the selectivity of the sorbent to cations, chemical, the modification is carried out in two stages, the first before heat treatment, and the second after heat treatment, and in the first stage, the modification is carried out with a solution of a reagent selected from the group: orthophosphoric acid, sodium silicate or phosphoric acid and aluminum salt, or phosphoric acid and sodium silicate, or phosphoric acid, aluminum salt and sodium silicate, and in the second stage, the modification is carried out with a reagent selected from the group: antimony, titanium, zirconium oxides, or titanium and zirconium phosphates, or transition ferrocyanide metal. 2. The method according to claim 1, on the basis of which the heat treatment is carried out at 300-600 ° C. 3. The method according to claim 1, with the exception that in the first stage of the modification, the treatment is carried out with a reagent solution or a mixture of reagents at the rate of 1-10 mmol per 1 g of clay. 4. The method according to claim 1, with the fact that the modification with a transition metal ferrocyanide is carried out by sequentially treating the clay with potassium ferrocyanide and a transition metal salt. 5. The method according to claim 1. characterized in that the modification with antimony, titanium or zirconium oxide is carried out by treating the clay with water-soluble antimony salts, titanium or zirconium with their subsequent hydrolysis. 6. The method according to claim 1, characterized in that. that modification with titanium or zirconium phosphate is carried out by sequentially treating the clay with a water-soluble salt of titanium or zirconium and phosphoric acid or alkali metal phosphate / 7. The method according to claims 1, 4, 5 and 6, with the exception that in the second stage, the modification is carried out at the rate of 0.1-2 mmol of reagent per 1 g of clay. Table table 2