Separation membrane for cesium in solution as well as preparation method and application of separation membrane

Abstract

The invention provides a separation membrane for cesium in a solution as well as a preparation method and application of the separation membrane, and belongs to the technical field of membrane separation. A layer of Prussian blue analogue particles with specific permeability to cesium ions is grown on the surface of a cation exchange membrane by utilizing an ion exchange-deposition growth method to form a separation membrane, and the method for continuously separating and enriching cesium from a water body under electric driving is developed by combining the advantages of high selectivity and continuous operation of membrane separation. And efficient selective separation of cesium ions in a water body is ensured while industrial continuous operation is realized.

Description

Technical Field

[0001] The present invention relates to the field of membrane separation technology, and more specifically, to a separation membrane for cesium in a solution, a preparation method and an application thereof. Background Art

[0002] Cesium is an important key metal, and its application areas mainly include the electronics industry, energy field, petroleum industry, and medical treatment. Whether cesium is extracted from ore, salt lake, or seawater, it needs to go through a solution state, and the cesium in the solution needs to be separated. In addition, electronic and chemical companies related to cesium may discharge a large amount of cesium-containing wastewater during the production process, and this part of cesium must also be separated and enriched. The cesium-containing wastewater generated during the treatment process in cesium-contaminated areas also needs to be separated.

[0003] After decades of development, research on removing cesium ions from wastewater is relatively extensive, among which membrane separation technology has been widely studied due to its high selectivity and good application prospects. Membrane separation has the advantages of simple operation and no secondary pollution, but the performance and cost of membrane materials are the key issues restricting its development. Among them, the main research directions of the technology of using membrane separation to treat wastewater containing cesium, strontium, lanthanum, and zirconium are membrane adsorption materials, filter membranes, liquid membranes, reverse osmosis membranes, and MD membranes. ZhaoyongYe et al. successfully prepared a new GO / PB modified nanofiltration membrane (PB content is 5wt%, GO content is 0.1wt%, PEG content is 15wt%) by combining graphene oxide and Prussian blue. The nanofiltration membrane has the advantages of both membrane separation and adsorption, and the water flux is 24.79L / (m 2 h), for Cs in wastewater + and Sr 2+ With ultra-high removal rates (99.5% and 97.5% respectively). Hyung-Ju Kim et al. studied the ability of nanofiltration (NF) membrane and reverse osmosis (RO) membrane to remove radionuclides (cesium, strontium and cobalt) from solutions. In the simulated seawater, the nanofiltration membrane showed a removal rate of 160 to 210 L·(m -2 ·h -1 ) high flux, while the reverse osmosis (RO) membrane showed 13 to 22 L·(m -2 ·h -1 ) has a low flux. However, reverse osmosis membranes are more effective in removing radionuclides (cesium, strontium and cobalt) in dilute aqueous solutions. The removal rate for single components exceeds 93%, and the removal rate for mixed radionuclides is even higher (>98%). Xi Zhang et al. used dopamine-modified bacterial cellulose (BC) as a template and designed a cesium ion imprinted composite membrane (I-DBC) by sol-gel surface imprinting technology. The results showed that the I-DBC composite membrane was more consistent with the Langmuir model and adsorbed Cs(I) mainly in the form of chemical monolayer adsorption. The maximum adsorption capacity under optimal conditions was 50.016 mg·g-1 In low-concentration wastewater, the maximum adsorption capacity of I-DBC is 4.093 mg·g -1 .

[0004] Since cesium is an alkali metal that is easily soluble in water, it is difficult to separate cesium from wastewater. The selectivity of traditional pressure membranes for cesium is not high, and the adsorption capacity of membrane adsorption methods is low, which makes it difficult to achieve the purpose of separating and enriching cesium ions from solutions. Therefore, efficient separation of cesium ions from contaminated water bodies is still a task that needs to be solved urgently. In the present invention, the high selectivity of ion exchange membranes is combined with the research on separating cesium from solutions by ion exchange membranes under electrical drive, which can achieve continuous separation of cesium from solutions. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a separation membrane for cesium in a solution, a preparation method and an application thereof, wherein a thin layer of a Prussian blue analogue having exclusive selectivity for cesium is grown on the surface of a cation exchange membrane by an ion exchange-deposition growth method. In the process of separating and enriching cesium in a solution, Prussian blue serves as an ion channel for cesium, thereby achieving efficient separation and enrichment of cesium.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A cesium separation membrane in a solution is composed of a cation exchange membrane and Prussian blue analog particles having exclusive permeability to cesium ions and grown on one side of the cation exchange membrane.

[0008] Furthermore, the cation exchange membrane is a sulfonic acid cation exchange membrane.

[0009] Further, the chemical formula of the Prussian blue analogue is A x M Ay [M B (CN) 6 ] Z -nH 2 O, where 0≤x≤2, 1≤y≤4, 1≤z≤3, A represents an alkali metal, M A and M B It is any one of Fe, Cr, Ti, Ni, Co, Mn, Cu and Zn. The value of n is not limited.

[0010] The above-mentioned method for preparing the separation membrane comprises the following steps:

[0011] S1, M Am Y n Solution and A x [M B (CN) 6 ] solution were placed on both sides of the electrolytic cell, and the middle of the electrolytic cell was separated by a cation exchange membrane.Am Y n With A x [M B (CN) 6 ] is 1 to 3:1, and the solution concentration is controlled at 0.01 mol / L to 1 mol / L;

[0012] Among them, M A =Fe, Cr, Ti, Ni, Co, Mn, Cu or Zn, Y = Cl - , SO2-4 or NO-3, F - ;A=K, Na or Li, X=3 or 4; M B =Fe, Cr, Ti, Ni, Co, Mn, Cu or Zn;

[0013] S2, using the current or concentration difference to make M A Ions pass through the cation exchange membrane and interact with A on the other side of the cation exchange membrane. x [M B (CN) 6 ]The reaction deposition growth forms a layer of Prussian blue analog particles that are exclusively permeable to cesium ions, thereby obtaining a separation membrane.

[0014] Furthermore, the concentration difference is used to make M A Ions pass through the cation exchange membrane as follows: Am Y n The end where the solution is located is set as the anode chamber, and the anode is inserted; A x [M B (CN) 6 The cathode chamber is set at one end where the solution is located, and the cathode is inserted. The temperature of the electrolysis system is controlled to be maintained at 25℃~60℃ and the current density is 0.5~50A / m 2 .

[0015] In this application, the concentration difference is used to make M A In the process of ions passing through the cation exchange membrane, there is no restriction on the concentration difference. A Ions can pass through the cation exchange membrane to the other side.

[0016] Furthermore, the separation membrane has a thickness of 50 to 1000 μm.

[0017] A method for efficiently separating and enriching cesium in a solution, using the above separation membrane as a diaphragm, placing a solution to be treated in the anode chamber, and a blank solution to be enriched in the cathode chamber, and under the action of electric current, cesium ions are enriched in the cathode chamber through the separation membrane from the anode chamber.

[0018] Further, the following steps are included:

[0019] S1. Construction of separation system:

[0020] The Prussian blue composite membrane is used as the diaphragm, the anode chamber is filled with the solution to be treated, and the cathode chamber is filled with the blank solution to be enriched;

[0021] S2. Separation of cesium ions in solution:

[0022] The electric field of the solution is controlled by the working electrode, so that cesium ions pass through the Prussian blue membrane and are enriched in the cathode chamber.

[0023] Furthermore, in the working electrode, the anode and the cathode can be inert electrodes or soluble electrodes.

[0024] Furthermore, the solution in the cathode chamber is an acidic or neutral solution (pH = -0.5 to 7), the solution in the anode chamber is an acidic or neutral solution (pH = -0.5 to 7), the electrolysis voltage is 0.5 to 10 V, and the current density is 0.5 to 50 A / m 2 .

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] The present invention adopts an ion exchange-deposition growth method to grow a layer of Prussian blue-like particles on the surface of a cation exchange membrane, thereby forming a separation membrane with exclusive permeability to cesium ions. The separation membrane has good selectivity for cesium, a simple preparation method, strong anti-interference ability, and can quickly separate and enrich cesium ions in a solution by combining an electric field. The separation membrane provided by the present invention can realize continuous separation of cesium ions from a solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the cesium separation device by diaphragm electrolysis (A) and schematic diagram of the separation membrane cross-section (B).

[0028] Figure 2 SEM-EDS images of the two sides of the separation membrane; a is the contact Figure 1 The surface of the membrane on the a side is the solution, and the surface on the b side is the contact Figure 1 The membrane surface of the solution on the b side. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] Example 1

[0033] Prepare 0.1 mol / L FeSO 4 Solution and 0.1mol / LK 3 [Fe(CN) 6 ] solution, FeSO 4 The solution is placed in the anode chamber and K 3 [Fe(CN) 6 ] is placed in the cathode chamber, and the middle of the two sides of the electrolytic cell is separated by a sulfonic acid cation exchange membrane. The solution temperature is controlled at 25°C and the current density is controlled at 0.5A / m 2 , a Prussian blue analogue was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 10 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 250 μm, recorded as M1. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0034] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 76.3%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =20.3, f Cs / La =69.1, f Cs / Zr =85.1.

[0035] Example 2

[0036] Prepare 0.1 mol / L CuSO 4 Solution and 0.1mol / LK 3 [Fe(CN) 6 ] solution, CuSO 4 The solution is placed in the anode chamber and K 3 [Fe(CN) 6 ] is placed in the cathode chamber, and the middle of the two sides of the electrolytic cell is separated by a sulfonic acid cation exchange membrane. The solution temperature is controlled at 25°C and the current density is controlled at 0.5A / m 2, a Prussian blue analogue was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 10 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 250 μm, recorded as M2. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0037] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 82.4%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =30.5, f Cs / La =70.9, f Cs / Zr =90.6.

[0038] Example 3

[0039] Prepare 0.1 mol / L CuSO 4 Solution and 0.1mol / LK 3 [Co(CN) 6 ] solution, CuSO 4 The solution is placed in the anode chamber and K 3 [Co(CN) 6 ] was placed in the cathode chamber, and the two sides of the electrolytic cell were separated by a sulfonic acid cation exchange membrane. The solution temperature was controlled at 30°C, the current was controlled at 0.001A, and a Prussian blue analog was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 10 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 250μm, recorded as M3. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0040] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 80.1%, and Cs + With Sr 2+ ,La3+ 、Zr 4+ The separation factor f Cs / Sr =25.4, f Cs / La =64.9, f Cs / Zr =84.3.

[0041] Example 4

[0042] Prepare 0.1 mol / L CoSO 4 Solution and 0.1mol / LK 4 [Fe(CN) 6 ] solution, CoSO 4 The solution is placed in the anode chamber and K 4 [Fe(CN) 6 ] is placed in the cathode chamber, and the middle of the two sides of the electrolytic cell is separated by a sulfonic acid cation exchange membrane. The solution temperature is controlled at 60°C and the current density is controlled at 0.5A / m 2 , a Prussian blue analogue was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 10 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 250 μm, recorded as M4. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0043] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 79.5%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =28.0, f Cs / La =56.5, f Cs / Zr =85.5.

[0044] Example 5

[0045] Prepare 0.1 mol / L CuSO 4 Solution and 0.1mol / LK 3 [Fe(CN) 6 ] solution, CuSO 4 The solution is placed in the anode chamber and K 3 [Fe(CN) 6] is placed in the cathode chamber, and the two sides of the electrolytic cell are separated by a sulfonic acid cation exchange membrane. The solution temperature is controlled at 60°C and the current density is controlled at 5A / m 2 , a Prussian blue analogue was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 10 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 300 μm, recorded as M5. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0046] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 95.7%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =119.7, f Cs / La =172.0, f Cs / Zr =336.8.

[0047] Example 6

[0048] Prepare 0.1 mol / L NiSO 4 Solution and 0.1mol / LK 3 [Fe(CN) 6 ] solution, NiSO 4 The solution is placed in the anode chamber and K 3 [Fe(CN) 6 ] is placed in the cathode chamber, and the middle of the two sides of the electrolytic cell is separated by a sulfonic acid cation exchange membrane. The solution temperature is controlled at 40°C and the current density is controlled at 50A / m 2 , a Prussian blue analogue was formed on the surface of the cation exchange membrane on one side of the cathode chamber. After 30 minutes, the separation membrane was taken out and stored in deionized water. The membrane thickness was 400 μm, recorded as M6. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0049] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+, 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 99.8%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =152.2, f Cs / La =247.4, f Cs / Zr =435.9.

[0050] Example 7

[0051] Prepare 0.1 mol / L CuSO 4 Solution and 0.1mol / LK 3 [Fe(CN) 6 ] solution, CuSO 4 The solution is placed in the anode chamber and K 3 [Fe(CN) 6 ] was placed in the cathode chamber, and the two sides of the electrolytic cell were separated by a sulfonic acid cation exchange membrane. The solution temperature was controlled at 40°C, and the Cu ions were driven to move only by the concentration difference. After 120 minutes, the membrane was taken out and stored in deionized water. The membrane thickness was 280μm, recorded as M7. The separation membrane was then used as a diaphragm to treat simulated cesium-containing wastewater using an electrolysis device.

[0052] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell. 3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 After electrolysis for 10 h, the removal rate of cesium was calculated to be 90.8%, and Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =72.2, f Cs / La =127.4, f Cs / Zr =235.9.

[0053] Comparative Example 1

[0054] An unmodified sulfonic acid cation exchange membrane with a membrane thickness of 200 μm was used, which was recorded as M8. An electrolysis device was used to treat simulated cesium-containing wastewater.

[0055] 1 g / L CsNO was placed in the anode chamber of the electrolytic cell.3 Solution 1L (pH = 2), coexisting ions include 1g / L Sr 2+ ,La 3+ 、Zr 4+ , 0.01mol / L nitric acid solution was used in the cathode chamber. Inert electrodes were inserted on both sides, and the current density was controlled to be 10A / m 2 , electrolysis for 10h, the removal rate of cesium was calculated to be 22.1%, Cs + With Sr 2+ ,La 3+ 、Zr 4+ The separation factor f Cs / Sr =0.9, f Cs / La =1.1, f Cs / Zr =1.5.

[0056] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A membrane for separating cesium in a solution, characterized in that: The invention is composed of a cation exchange membrane and Prussian blue analog particles having exclusive permeability to cesium ions grown on the surface of one side of the cation exchange membrane.

2. The separation membrane according to claim 1, characterized in that The cation exchange membrane is a sulfonic acid type cation exchange membrane.

3. The separation membrane according to claim 1, characterized in that The chemical formula of the Prussian blue analogue is A x M Ay [M B (CN)6] Z -nH2O, where 0≤x≤2, 1≤y≤4, 1≤z≤3, A represents an alkali metal, M A and M B It is any one of Fe, Cr, Ti, Ni, Co, Mn, Cu and Zn. The value of n is not limited.

4. The method for preparing a separation membrane according to any one of claims 1 to 3, characterized in that: The steps include: S1, M Am Y n Solution and A x [M B The (CN)6] solution was placed on both sides of the electrolytic cell, and the middle of the electrolytic cell was separated by a cation exchange membrane. Am Y n With A x [M B The molar ratio of (CN)6] is 1 to 3:1, and the solution concentration is controlled at 0.01 mol / L to 1 mol / L; Among them, M A =Fe, Cr, Ti, Ni, Co, Mn, Cu or Zn, Y = Cl - , SO2-4 or NO-3, F - ;A=K, Na or Li, X=3 or 4; M B =Fe, Cr, Ti, Ni, Co, Mn, Cu or Zn; S2, using the current or concentration difference to make M A Ions pass through the cation exchange membrane and interact with A on the other side of the cation exchange membrane. x [M B (CN)6] reaction deposition growth forms a layer of Prussian blue analog particles that are exclusively permeable to cesium ions, thereby obtaining a separation membrane.

5. The preparation method according to claim 4, characterized in that: The specific use of current is: Am Y n The end where the solution is located is set as the anode chamber, and the anode is inserted; A x [M B The end where the (CN)6] solution is located is set as the cathode chamber, the cathode is inserted, and the temperature of the electrolysis system is controlled to be maintained at 25℃~60℃, and the current density is 0.5~50A / m 2 .

6. The preparation method according to claim 4, characterized in that: The separation membrane has a thickness of 50 to 1000 μm.

7. A method for separating and enriching cesium in a solution, characterized in that: The separation membrane described in any one of claims 1 to 3 is used as a diaphragm, the anode chamber is filled with a solution to be treated, the cathode chamber is a blank solution to be enriched, and under the action of electric current, cesium ions are enriched in the cathode chamber through the separation membrane from the anode chamber.

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