SU654623A1 - Method of obtaining copper-containing electron-ion exchanger - Google Patents

Description

(54) METHOD FOR PREPARING THE COPPER-CONTAINING ELECTRON-ION EXCHANGER In addition, toxic reagents (sodium hydrosulfite) are used in chemical reduction, contaminating the wash water discharges, and a large amount of dehydrated water is used for washing (after the recovery stage). The purpose of the invention is to increase the redox capacity of the metal-reducing agent, to increase the fixing strength of the metal reducing agent on the fibrous ion exchanger matrix. This is achieved by using a bipolar fibrous polyacrylonitrile ion exchanger as a fibrous ion exchanger, containing in its structure weakly acidic and weakly basic ionic groups in a molar ratio of 0.4: 1 to 1: 1. The saturation of the ion exchanger with copper ions and the formation of copper ions are preferably carried out by an electrochemical method in the cathode chamber of the electrodialyzer at a constant current density of 8-10 mA / cm in an amount of 120-130 Ah-h at saturation of 250-300 Ah at a reduction of Lenin per 1 kg ionite at room temperature for 135150 minutes The fibers used contain ionic, carboxyl and amine groups, the ratio of which is determined by the conditions for their preparation. Sugar shaped PAP fibers with a final 8–9 stretch are treated in a reaction mixture containing 120 g / l sodium hydroxide and 100–120 g / l hydrochloric acid (sulphate) hydrazine at 90 ° C for 10–150 min. SOYN on amine and carboxyl groups reaches 1.5-3.2 and 3.5-4.2 mEq / g, respectively. In the course of such treatment, the interaction of caustic Natra with nitrile (C K) groups leads to the formation of carboxyl groups. The presence of hydrazine derivatives in the reaction medium as a crosslinking agent leads to the formation of amine groups of the type: —KH; -NHNHj; -N-NH. The hydrophobicity obtained by the will of the con is in the range of 22-26%. The floor of the fiber is sufficiently structured and resistant to the action of mineral jiOT and alkalis in a wide range p The semiconductor properties of the fiber are acquired during the alkaline treatment process. Iodine by the action of caustic soda occurs isomerization of the nitrile groups of PAN, leading to the appearance of conjugated double bonds. 1P: - electrons arising in conjugated double bonds have a high mobility, which causes the electronic conductivity of the fibrous bipolar ion exchanger. In addition, such polymers have increased polarization of the “-th molecules containing nitrogen atoms, which () allows for electronic conductivity. The values of resistivity of fibers treated for 20 and 120 minutes in air at 20 ° C are within the limits of the semiconductor properties of double-conjugated polymers. Fiber polyampholytes possess enhanced molecular sorption with respect to metals of variable valence (12-14 meq / rJ. As a result of electrochemical reduction, the reducing metal from the matrix of copper-containing fiber PAN ionite is not mechanically removed, and the resulting EY has a stable redox capacity. This is due to the fact that the electrochemical reduction occurs throughout the entire mass of the fibrous ion exchanger when it is in a constant electric field. the number of metal-reducing agents in the fiber after passing a certain amount of water.Water, Metal-reducing agent, l / g EY mEq./g 10 8.6 20. 8.68 30 8.64 40 8.62 50 .8.62; 8 , 61 Example 1. Polyacrylonitrile ion-exchange fiber with anion and cation-exchange capacity of 1.5 and 4.0 mHEq / g, respectively, is saturated with copper ions in a 1% CuSO solution in the cathodic chamber of a two-chamber: electrodialyzer for 210 minutes (with per 1 kg of fiber, 1 l of CuSQ solution) by passing a constant electric current with a density of 8-10 mA / cm in an amount of 130. A fiber saturated with copper ions, after washing from a solution of copper sulfate, is placed for recovery in the cathode chamber of an electrodialyzer filled with 0.02 n. solution. The electrochemical reduction process is carried out at room temperature for 135 minutes under the influence of a constant electric current with a density of 8-10 mA / cm. At the end of the reduction process, the produced EY is washed off with a small amount of deoxygenated water from weakly fixed metallic copper and its oxides. The total reduction capacity (OCEE) after the first treatment cycle is 8.0-8.4 mEq / ml at a current output of 80-90%. After repeating the above operations. in the third cycle, OBE reaches a value of 7.0-7.5 mHEq / g (14-15 mEq / ml) at a current output of 80%. The reducing ability of O2 -208 mg (fiber.

Example 2 Polyacrylonitrile ion-exchange fiber, containing in its structure of amine groups 2.5 mg eq / g, carboxial 2.5 mg eq / g, is saturated with copper ions in a 2% CuSO solution in the cathode chamber of the electrolyzer per 1 kg of fiber 1 l of CuSO solution, pass a constant electric current with a density of 9-10 mA / cm in the amount of

5 GEKv / g of ion exchanger 120 Ah.

Further, copper reduction operations are carried out as in Example 1 for 150 minutes. The resulting HE has an OBE of 7.0-7.4 mHEq / ml at a current rating of 80-90%. After the third processing cycle using the same technology.

OUli reaches 6, 5-, O mg-eq / g (13.414, 0 mg eqv / 1l) at a current output of 80%. The reducing power of O is 192 mg of fiber. Protection of oxidative processes in the electrochemical reduction stage is carried out by introducing MA-40 membranes into electrodialiener electrochemically active.

When using unipolar fibrous PAN ion exchangers saturated with copper ions, their reduction to zero valence under the action of electric current does not occur, which seems to be. It can be explained by the fact that there is no transfer of electrons through the matrix of a fibrous ion exchanger.

The results are shown in the table.

9.4-9.8

PAN fiber with anionic and cation exchanges with a capacity of 1.5 mg eq / g and 4-5 mg eq / g

Ion exchange P7Sh fiber with anionic and cation exchange capacity of 2.5

ICGEO / H and

Claims (2)

2.5 mEq / g, respectively. The implementation of the proposed method does not require toxic reagents (sodium hydrosulfite), and a small amount of deoxygenated water is required for washing the obtained EI. Formula 1: A method for producing a copper-containing electron-ion exchanger, including treatment of fibrous polyacrylonitrile ion exchanger with copper sulfate solution copper ion recovery to Electrochemical reduction does not occur. 8.0-8.4 14-15 7.0-7.4 13-14 zero valence, characterized in that, in order to increase the redox capacity and the strong fixation of the reducing metal on the ion exchanger matrix, fibrous bipolar polyacrylonitrile ion exchanger is used as the fibrous ion exchanger, the contents of weakly basic and weakly acidic ionic groups in the ratio from 0 4: 1 to. 2. The method according to p. 1, that is, with the fact that the processing of pactaoDOM sulphate nesw and recovery 7 654623. 8 copper ions are electrochemicalsources of information taken in method in the cathode chamber electro-Enimania during the examination dialyzer at constant current with dense. x „v 120–1 mA / cm in the amount of 120–1. Kozhevnikov A.V. Elektrono130 Agch at saturation and 250–300 A chion exchangers. L., Himi, 1972. when restoring per 1 kg fibrous ion exchanger at room 5 2. USSR copyright certificate temperature for 135-150 min. V292004, cl. On 01 F 11/04, 1971.