Method for capturing and detecting metal ions in a water body and capturing device

Abstract

The application discloses a method for capturing and detecting metal ions in water bodies and a capturing device. The method for capturing and detecting metal ions in water bodies comprises the following steps: S1, taking a water body sample containing metal ions as a to-be-tested liquid; S2, loading an adsorption material into a chromatographic column as an adsorption layer, and making the to-be-tested liquid pass through the chromatographic column to perform an adsorption operation, and then recycling the adsorbed liquid into the chromatographic column; and S3, detecting the adsorbed metal ions and calculating a capture rate. The capturing and detecting method has the technical effects of high capture rate and fast capture speed for capturing metal ions, especially radioactive ions.

Description

Technical Field

[0001] This invention relates to the field of instrument development technology, specifically to a method and device for capturing and detecting metal ions in water. Background Technology

[0002] The capture and monitoring of metal ions is an essential supporting technology for the development of many industries. In industries such as metal smelting, mineral processing, and electronics manufacturing, effectively removing metal ions from wastewater and conducting long-term monitoring of environmental water bodies are crucial requirements for sustainable industrial development and continuous technological progress. Among various metal ion capture and detection scenarios, the demand for nuclear wastewater detection is becoming increasingly important with the continuous development of China's nuclear industry. Taking cesium as an example, China currently conducts more than 7,000 radioactive water sample tests annually, maintaining an annual growth rate of nearly 10%.

[0003] However, the current nuclear fission metal ion detection industry lacks suitable commercial equipment and standardized detection methods. China issued the latest "Marine Industry Standard of the People's Republic of China - Technical Regulations for Monitoring Radionuclides in the Marine Environment" in 2018. Its detection of cesium ions still uses a technical scheme of ammonium phosphomolybdate natural sedimentation-filtration-β-ray testing. This gravity-based natural sedimentation method cannot guarantee detection time and has a significant detection error, failing to provide a more standardized and controllable detection process. Therefore, developing a radioactive ion capture and analysis method and equipment with clearly controllable parameters, minimizing human error, and a simple control structure has become one of the important goals pursued by researchers.

[0004] Meanwhile, existing research on materials for metal ion capture often focuses more on the metal capture capacity and adsorption selectivity. Taking cesium as an example, CN111871363A discloses an adsorption material supported on silica, preliminarily exploring the possibility of dispersing ammonium phosphomolybdate on an inorganic support; however, its effect still cannot meet the requirements for rapid capture of cesium ions. Furthermore, the use of complex compounds such as MOFs (CN107855110A) and layered sulfides (CN101676032A) requires further refinement in terms of adsorption kinetics and material stability.

[0005] In summary, there is a need to develop a device that, in conjunction with novel detection materials, can stably and efficiently capture and detect metal ions, especially radioactive ions, to meet the requirements for rapid capture and detection of metal ions, particularly radioactive ions, in the ocean. Summary of the Invention

[0006] The technical problem this invention aims to solve is the slow capture rate and excessively long detection cycle of metal ions that cause environmental pollution in water bodies in existing technologies. This invention provides a method and device for capturing and detecting metal ions in water bodies. The capture and detection method of this invention achieves high capture rates and fast capture speeds for metal ions, especially radioactive ions.

[0007] The first aspect of this invention provides a method for capturing and detecting metal ions in water, comprising the following steps:

[0008] S1. Take a water sample containing metal ions as the test solution;

[0009] S2. The adsorbent material is loaded into the chromatography column to form the adsorption layer. The test solution passes through the chromatography column for adsorption. The adsorbed liquid is then recycled back into the chromatography column.

[0010] S3. Detect the adsorbed metal ions and calculate the capture rate.

[0011] Further, in step S1, the metal ions contained in the test solution include non-radioactive metal ions and / or radioactive metal ions; the non-radioactive metal ions are preferably at least one of Cs, Co, and Mn; the radioactive metal ions are preferably at least one of radioactive Cs, radioactive Co, and radioactive Mn. For example, the radioactive Cs ion can be at least one of Cs-133, Cs-134, and Cs-137, preferably Cs-137.

[0012] Further, in step S1, the concentration of non-radioactive metal ions in the test solution is 0.01–50 mg / L, preferably 0.05–30 mg / L.

[0013] Further, in step S1, the volume activity of the radioactive metal ions in the test solution is 0.001 to 50 Bq / L.

[0014] Further, in step S1, an acidic adjuster is preferably added to the test solution to adjust the pH to 2-7. The pH adjustment can be performed using an acidic adjusting solution conventionally used in the art, such as hydrochloric acid.

[0015] Further, in step S1, when the metal ion is a radioactive metal ion, a corresponding non-radioactive metal source can preferably be added. For example, when the captured metal ion is a radioactive cesium ion, non-radioactive cesium chloride can preferably be added. The purpose of adding it is to increase the overall concentration of metal ions in the solution, thereby better capturing radioactive ions. The mass ratio of the non-radioactive metal source to the test solution is 0.01–50 mg / L, preferably 0.05–30 mg / L, wherein the metal source is by mass and the test solution is by volume.

[0016] Furthermore, in step S1, the water body can be industrial water, domestic water, seawater, fresh water, or other water bodies.

[0017] Further, in step S2, the solid-liquid ratio of the adsorbent material and the test liquid is 0.02 to 1 g / L, preferably 0.05 to 0.5 g / L.

[0018] Further, in step S2, the adsorbent material is selected from at least one of ammonium phosphomolybdate, ammonium phosphomolybdate-polyacrylonitrile, layered sulfide, and SCM-IC-1 molecular sieve composite material, wherein SCM-IC-1 molecular sieve composite material is preferred.

[0019] Furthermore, in step S2, the test solution is adsorbed through the adsorption layer of the chromatography column. The injection method can be achieved by using a pump to inject the test solution before or after the chromatography column, and the injection flow rate of the test solution, i.e., the mass hourly space velocity, can be controlled.

[0020] Further, in step S2, the test solution is adsorbed through a chromatography column, and the operating parameters include: the operating temperature is 5-40℃, preferably 10-35℃; the mass hourly space velocity (MAV) of the test solution is 0.02-5 L / (g·h), preferably 0.03-3 L / (g·h); wherein, the MAV is the volume of test solution injected per hour relative to the adsorbent material.

[0021] Furthermore, in step S2, the cycle ends after the target capture rate is reached, and the adsorption time is 1 to 150 hours, preferably 1 to 120 hours.

[0022] Furthermore, in step S3, when the metal ions to be captured are non-radioactive metal ions, the test solution after adsorption in S2 needs to be detected and the capture rate calculated.

[0023] Furthermore, in step S3, when the metal ions to be captured are radioactive metal ions, it is necessary to use γ-rays to determine the amount of radioactive particles in the adsorption layer and calculate the capture rate of radioactive metal ions.

[0024] Further, in step S3, the operation steps for the γ-ray measurement are as follows: the adsorption layer is placed in the cavity of the γ-ray tester, tested for 5 to 20 hours, the number of decaying particles is recorded, the relative decay constant is calculated to determine the total number of radioactive particles, and thus the collection efficiency of the adsorption material provided by the present invention for radioactive ions is calculated.

[0025] Further, in step S2, the SCM-IC-1 molecular sieve composite material includes a porous silicon-aluminum crystal component, an ammonium phosphomolybdate component, and a silicon-based binder component.

[0026] Further, in step S2, in the SCM-IC-1 molecular sieve composite material, the shortest linear distance between Mo and Al elements is <200 nm, preferably 10–150 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, etc., and any value within any range formed by any two of these values. In this invention, in the SCM-IC-1 molecular sieve composite material, the Mo and Al elements at this distance can cause a synergistic effect between ammonium phosphomolybdate and the two active phases of the molecular sieve, significantly improving the collection efficiency.

[0027] Further, in step S2, the SCM-IC-1 molecular sieve composite material has a spherical or near-spherical morphology, and its average particle size is 20-150 μm, preferably 30-120 μm, such as 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, etc., and any value in any range formed by any two of these values, more preferably 50-100 μm.

[0028] Further, in step S2, the chemical composition of the silicon-aluminum porous crystal component in the SCM-IC-1 molecular sieve composite material is “xNa2O·ySiO2·xAl2O3”, and satisfies 0.01≤x / y≤0.30, preferably 0.015≤x / y≤0.250, in molar terms.

[0029] Further, in step S2, the silicon-aluminum porous crystal component in the SCM-IC-1 molecular sieve composite material has one or more of the topological structures of MWW, FAU, BEA, MOR, ATS, CHA, and MFI molecular sieves, preferably one or more of the topological structures of MWW, FAU, CHA, and MFI, and more preferably the topological structure of MWW.

[0030] Furthermore, in step S2, the SCM-IC-1 molecular sieve composite material contains porous silicon-aluminum crystals with spherical, plate-like, or rod-like crystal structures.

[0031] Further, in step S2, in the SCM-IC-1 molecular sieve composite material, the silicon-based binder component is derived from a silicon-based compound, preferably from at least one of silica sol, tetraethyl silicate, and tetrabutyl silicate.

[0032] Further, in step S2, in the SCM-IC-1 molecular sieve composite material, based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the silicon-aluminum porous crystal component is 8-30%, preferably 12-25%, for example 12%, 15%, 20%, 21%, 22%, 23%, 25%, 30%, etc., and any value within any range formed by any two of these values.

[0033] Further, in step S2, in the SCM-IC-1 molecular sieve composite material, based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the ammonium phosphomolybdate component is 20-65%, preferably 30-60%, for example 30%, 35%, 37%, 40%, 45%, 48%, 50%, 55%, 60%, etc., and any value within any range formed by any two of these values.

[0034] Further, in step S2, in the SCM-IC-1 molecular sieve composite material, based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the silicon-based binder component is 25-50%, preferably 35-45%, for example 25%, 28%, 31%, 35%, 40%, 42%, 45%, etc., and any value within any range formed by any two of these values.

[0035] Further, in step S2, the preparation method of the SCM-IC-1 molecular sieve composite material includes the following steps:

[0036] (1) Mix porous silicon-aluminum crystals with water and heat them to activate them to obtain a solid precursor;

[0037] (2) The solid precursor is mixed with ammonium phosphomolybdate, a silicone binder and water to obtain a mixture;

[0038] (3) The mixture was spray-molded to obtain SCM-IC-1 molecular sieve composite material.

[0039] Further, in step (1), the chemical composition of the silicon-aluminum porous crystal is "xNa2O·ySiO2·xAl2O3", and satisfies 0.01≤x / y≤0.30, preferably 0.015≤x / y≤0.250. The structure of the silicon-aluminum porous crystal has one or more of the topological structures of MWW, FAU, BEA, MOR, ATS, CHA, and MFI molecular sieves, preferably one or more of the topological structures of MWW, FAU, CHA, and MFI, and more preferably the topological structure of MWW.

[0040] Furthermore, in step (1), the porous silicon-aluminum crystal has a spherical, plate-like, or rod-like crystal structure.

[0041] Further, in step (1), the mass ratio of the porous silicon-aluminum crystal to water is 1:(5-50), preferably 1:(10-40).

[0042] Further, in step (1), the operating conditions for the heating activation include: a temperature of 40 to 80°C and a processing time of 0.5 to 4 hours, preferably a temperature of 50 to 70°C and a processing time of 0.5 to 2 hours.

[0043] Furthermore, in step (1), the present invention further includes a solid-liquid separation process after heating and activation. There are no particular limitations on the solid-liquid separation process, and it can be carried out with reference to commonly used methods in the art.

[0044] Further, in step (2), the silicon-based binder is a silicon-based compound, preferably selected from at least one of silica sol with a silica concentration of 30-40 wt%, tetraethyl silicate, and tetrabutyl silicate.

[0045] Further, in step (2), the silicon-based binder is based on silicon dioxide, the solid precursor is based on porous silicon-aluminum crystals, and the mass ratio of the solid precursor to ammonium phosphomolybdate and silicon-based binder is 1:(1-6):(0.75-5), preferably 1:(2-5):(1.7-4), and more preferably 1:(2-5):(2-4).

[0046] Further, in step (2), the solid-liquid ratio in the mixture is 0.1 to 0.5 by mass, preferably 0.2 to 0.5.

[0047] Furthermore, in step (3), the operating conditions for spray molding include: the equipment spray temperature is 150-250°C, preferably 180-240°C.

[0048] A second aspect of the present invention provides a device for capturing and detecting metal ions in water, comprising an initial water tank, a chromatography column, a liquid pump, and optionally a gamma-ray detector;

[0049] The initial water tank is connected to the upper inlet of the chromatography column, the lower outlet of the chromatography column is connected to the upper inlet of the liquid pump, and the lower outlet of the liquid pump is connected to the initial water tank containing the sample to be tested.

[0050] Furthermore, the inner diameter of the chromatography column is between 8 and 30 mm, and its height is between 5 and 30 cm. The column body is made of a transparent, weakly γ-ray absorbing material, preferably selected from at least one of polystyrene, polypropylene, polycarbonate, polyamide, and inorganic glass.

[0051] Furthermore, the liquid pump is a device that provides power to the liquid and controls the liquid flow rate, preferably a rotary pump. Specifically, it can be selected from one of a mixed-flow pump, an axial-flow pump, or a vane pump, and should include upper and lower liquid inlet and outlet ports.

[0052] Furthermore, the gamma-ray detector has a detection cavity of not less than 2L, preferably a detection cavity of 2 to 5L.

[0053] Furthermore, when the gamma-ray detector is in operation, the adsorbent material after column chromatography needs to be placed into the gamma-ray instrument for further processing.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] The capture and detection method and apparatus provided by this invention have the technical advantages of high metal ion capture rate and fast capture speed. In particular, the method provided by this invention differs from conventional metal ion detection methods by employing column chromatography and utilizing liquid circulation chromatography, resulting in an excellent metal ion capture rate, especially for radioactive metal ions, achieving complete capture in a shorter time. Attached Figure Description

[0056] Figure 1 A schematic diagram of the collection and detection device provided by the present invention;

[0057] Figure 2 The image shows the XRD pattern of the SCM-IC-1 molecular sieve composite material prepared in Example 4 of this invention.

[0058] Figure 3 This is a SEM image of the SCM-IC-1 molecular sieve composite material prepared in Example 4 of this invention;

[0059] Among them, Figure 1 In the diagram, number 1 is the initial water tank, 2 is the chromatography column, and 3 is the liquid pump. Detailed Implementation

[0060] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention. The specific implementation method of the present invention can be as follows:

[0061] The test solution is first placed in the initial water tank, then injected into the chromatography column, flows out from the lower outlet of the chromatography column, enters the liquid pump, and then circulates back to the initial water tank; after the circulation is completed, the test solution is tested, or the adsorbent material in the chromatography column is taken out and placed in a gamma-ray instrument for the detection of radioactive elements.

[0062] Furthermore, in this invention, the liquid to be tested in the initial water tank is injected into the chromatography column, and the injection rate and space velocity are controlled by utilizing the pressure difference between the initial water tank and the inlet of the chromatography column, as well as the liquid pump after the chromatography column.

[0063] For example Figure 1 As shown, the device includes an initial water tank 1, a chromatography column 2, and a liquid pump 3, as well as a gamma-ray detector;

[0064] The initial water tank is connected to the upper inlet of the chromatography column, the lower outlet of the chromatography column is connected to the upper inlet of the liquid pump, and the lower outlet of the liquid pump is connected to the initial water tank containing the sample to be tested.

[0065] Furthermore, the liquid pump used in the embodiments and comparative examples is a vane pump.

[0066] In the context of this specification, the structure of the sample is determined by X-ray diffraction (XRD), which is measured by an X-ray powder diffractometer using a Cu-Kα ray source and a nickel filter.

[0067] In the context of this specification, the X-ray powder diffractometer used to analyze the sample is a Panalytical XPERPRO X-ray powder diffractometer, and the CuKα ray source is used to analyze the phase composition of the sample. Nickel filter, 2θ scanning range 2~50°, operating voltage 40kV, current 40mA, scanning rate 10° / min.

[0068] In the context of this specification, the scanning electron microscope (SEM) used for the sample is an S-4800II field emission scanning electron microscope. The crystal size of the sample was measured as follows: the molecular sieve was observed using this SEM at 10,000x magnification. A field of view was randomly selected, and the average sum of the crystal sizes in that field of view was calculated. This operation was repeated 10 times. The average sum of the 10 averages was taken as the crystal size.

[0069] In the context of this specification, the shortest linear distance between Mo and Al elements in the material was determined by observing the distance between any Mo bright spot and its nearest Al bright spot in a randomly selected field of view using a transmission electron microscope (FEI G2F30 transmission electron microscope, operating voltage 300kV) at a magnification of 100,000x in EDS mode. Thirty different Mo bright spots were measured using the above procedure, and the average distance was taken.

[0070] In the context of this specification, the inductively coupled plasma atomic emission spectrometer (ICP) used is a Varian 725-ES. For solid samples, the sample is dissolved in hydrofluoric acid to determine the elemental content, expressed in moles, thereby determining the sample component content. For solutions, the content of each element in the solution is directly measured.

[0071] In the context of this specification, including in the embodiments, the formula for the capture rate of the non-radioactive cesium metal ions is:

[0072] The capture rate % of non-radioactive cesium ions is calculated as (c0-c1) / c0×100%; where c0 is the initial mass concentration of metal ions in the test solution, and c1 is the mass concentration of metal ions in the test solution after capture.

[0073] In the context of this specification, including the following examples and comparative examples, the measured radioactive cesium ion capture rate is extrapolated from the captured radioactive Cs-137, and is measured by using a gamma-ray counter to measure the content of gamma decay rays captured by the instrument per unit time. In step S1, a Cs-137 solution is added to a selected water sample (deionized water) to achieve a specific range of radioactive volume activity of radioactive cesium in the water, thus simulating a radioactive water sample from industrial or domestic use.

[0074] The formula for the capture rate of radioactive cesium ions is:

[0075] Radioactive cesium ion capture rate % = γ1*t0 / (γ0*t1)×100%; γ1 is the radiation dose of the adsorbed layer after capture in the gamma-ray test, and t1 is the gamma-ray test time. In contrast, γ0 and t0 are the test radiation dose and test time of the standard, respectively.

[0076] Example 1

[0077] Adopting such Figure 1 The equipment and process flow.

[0078] Add 500 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, with a volume activity of 0.5 Bq / L for Cs-137), mix well, and add hydrochloric acid to adjust the pH to 3.

[0079] The column chromatography module has an inner diameter of 30 mm and a height of 10 cm. The column body is made of polystyrene, and the packing material, i.e., the adsorbent, is 20 g of ammonium phosphomolybdate (AMP). At 20 °C, the above-mentioned test solution was injected into the chromatography column at a mass hourly space velocity (MSV) of 0.1 L / (g·h), and the adsorbed liquid flowed back into the initial water tank. This cycle of adsorption was repeated for 50 h to complete the capture of radioactive cesium ions.

[0080] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0081] Example 2

[0082] Adopting such Figure 1 The equipment and process flow.

[0083] Add 500 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, with a volume activity of 0.5 Bq / L for Cs-137), mix well, and add hydrochloric acid to adjust the pH to 3.

[0084] The column chromatography module uses a 20mm inner diameter and a 10cm height polystyrene column as the packing material, which is 20g of ammonium phosphomolybdate (AMP). At 20℃, the analyte was injected into the column at a mass space velocity of 0.1L / (g·h) using a pump. The adsorbed liquid flowed back into the initial water tank, and the cycle was repeated for 120 hours to capture radioactive cesium ions.

[0085] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0086] Example 3

[0087] Adopting such Figure 1 The equipment and process flow.

[0088] Add 500 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, where the volume activity of Cs-137 is 1 Bq / L), mix well, and add hydrochloric acid to adjust the pH to 3.

[0089] The column chromatography module uses a 20mm inner diameter and a 10cm height column made of polystyrene. The packing material, i.e., adsorbent, is 50g of ammonium phosphomolybdate-polyacrylonitrile (AMP-PAN). At 20℃, the analyte solution was injected into the column at a mass hourly space velocity (MSH) of 0.04 L / (g·h) using a pump. The adsorbed liquid then flowed back into the initial water tank. This cycle of adsorption was repeated for 40 hours to capture radioactive cesium ions.

[0090] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0091] Example 4

[0092] Adopting such Figure 1 The equipment and process flow.

[0093] Add 500 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, with a volume activity of 0.5 Bq / L for Cs-137), mix well, and add hydrochloric acid to adjust the pH to 3.

[0094] The column chromatography module has an inner diameter of 20 mm and a height of 10 cm. The column body is made of polystyrene, and the packing material (adsorbent) is 20 g of SCM-IC-1 molecular sieve composite material. At 20 °C, the analyte was injected into the column at a mass hourly space velocity (MHSV) of 2.5 L / (g·h) using a pump. The adsorbed liquid flowed back into the initial water tank, and the cycle was repeated for 1 h to capture radioactive cesium ions.

[0095] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0096] The preparation process of the SCM-IC-1 molecular sieve composite material is as follows:

[0097] 100g of Na-type MCM-22 molecular sieve (0.033Na2O·SiO2·0.033Al2O3) was added to 2L of deionized water, stirred and heated to 50℃, maintained for 1h, and then centrifuged and decanted to obtain a solid precursor. The morphology of the MCM-22 molecular sieve was multilayered and plate-like.

[0098] Add 200g of ammonium phosphomolybdate, 500g of 40wt% silica sol solution, and deionized water to the solid precursor (100g Na-type MCM-22 molecular sieve) and stir until homogeneous to prepare a 1.5L mixed emulsion (solid-liquid mass ratio of 0.5).

[0099] The above mixed emulsion was injected at a rate of 50 mL / min and spray-molded at an operating temperature of 200 °C to obtain the SCM-IC-1 molecular sieve composite material.

[0100] The obtained material XRD pattern is as follows Figure 2 As shown in the figure, XRD analysis reveals that the material retains the MWW molecular sieve and ammonium phosphomolybdate structure overall. The SEM image of the material is shown below. Figure 3 As shown, it is spherical. The molecular sieve content is 21% by mass, the ammonium phosphomolybdate content is 41% by mass, the silicon-based binder content is 38% by mass, the particle size of the SCM-IC-1 molecular sieve composite material is 60 μm, and the shortest linear distance between Mo and Al elements is 40 nm.

[0101] Example 5

[0102] Adopting such Figure 1 The equipment and process flow.

[0103] Add 200 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, with a volume activity of 0.5 Bq / L for Cs-137), mix well, and add hydrochloric acid to adjust the pH to 3.

[0104] The chromatography column in the column chromatography module has an inner diameter of 20 mm and a height of 10 cm. The column body is made of polystyrene, and the packing agent, i.e., the adsorbent, is 20 g of SCM-IC-1 molecular sieve composite material (same as in Example 4). At 20°C, the above-mentioned test solution was injected into the chromatography column at a mass space velocity of 2.5 L / (g·h) using a pump injection method. The adsorbed liquid flowed into the initial water tank, and the adsorption was circulated for 4 h to complete the capture of radioactive cesium ions.

[0105] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0106] Example 6

[0107] Adopting such Figure 1 The equipment and process flow.

[0108] Add 200 mg of CsCl to 50 L of the test solution (a seawater sample containing Cs-137, with a volume activity of 0.5 Bq / L for Cs-137), mix well, do not add hydrochloric acid, and maintain pH = 7.

[0109] The column chromatography module has an inner diameter of 20 mm and a height of 10 cm. The column body is made of polystyrene, and the packing material (adsorbent) is 20 g of SCM-IC-1 molecular sieve composite material. At 20 °C, the analyte was injected into the column at a mass hourly space velocity (MHSV) of 1 L / (g·h) using a pump. The adsorbed liquid then flowed back into the initial water tank, and the cycle was repeated for 1 h to capture radioactive cesium ions.

[0110] The adsorbent material from the chromatography column was removed and placed in a γ-ray detector. After 10 hours, the amount of Cs-137 radioactive particles was measured, and the Cs-137 capture rate was calculated. The results are shown in Table 1.

[0111] The preparation process of the SCM-IC-1 molecular sieve composite material is as follows:

[0112] 50g of Na-type MCM-22 molecular sieve (0.033Na2O·SiO2·0.033Al2O3) was added to 2L of deionized water, stirred and heated to 50℃, maintained for 1h, and then centrifuged and decanted to obtain a solid precursor. The morphology of the MCM-22 molecular sieve was multilayered and plate-like.

[0113] Add 250g of ammonium phosphomolybdate, 500g of 40wt% silica sol solution, and deionized water to the solid precursor (50g Na-type MCM-22 molecular sieve) and stir until homogeneous to prepare a 1.5L mixed emulsion (solid-liquid mass ratio of 0.5).

[0114] The above mixed emulsion was injected at a rate of 50 mL / min and spray-molded at 200 °C to obtain the SCM-IC-1 molecular sieve composite material.

[0115] The obtained material XRD pattern and Figure 2 Similarly, XRD analysis shows that the material retains the MWW molecular sieve and ammonium phosphomolybdate structure overall. The SEM image of the material is similar to... Figure 3 As shown, it is spherical. The molecular sieve content is 12% by mass, the ammonium phosphomolybdate content is 48% by mass, the silicon-based binder content is 40% by mass, the particle size of the SCM-IC-1 molecular sieve composite material is 50 μm, and the shortest linear distance between Mo and Al elements is 50 nm.

[0116] Example 7

[0117] Same as Example 4, except that CsCl is not added to the test solution, nor is hydrochloric acid added to adjust the pH.

[0118] The chromatography time was 4 hours. The Cs-137 capture rate is shown in Table 1.

[0119] Example 8

[0120] Same as Example 4, except that the test solution does not contain radioactive Cs-137. The test solution is a seawater sample with 500 mg of CsCl added, mixed evenly, and hydrochloric acid added to adjust the pH to 3.

[0121] After 1 hour of cyclic adsorption to complete the capture of cesium ions, the concentration of cesium metal in the test solution was measured to calculate the cesium capture rate. The results are shown in Table 1.

[0122] Comparative Example 1

[0123] The analysis and testing were performed using methods based on national standards in this field. The procedure was as follows:

[0124] 20 g of AMP was poured into 50 L of the same test solution as in Example 1 and allowed to settle for 7 days. The adsorbed Cs-AMP material was obtained by decantation and filtration. Under the same detection conditions as in Example 1, a gamma-ray detector was used to determine the amount of Cs-137 radioactive particles and calculate the Cs-137 recovery rate.

[0125] The evaluation results are listed in Table 1.

[0126] Comparative Example 2

[0127] The trapping effect was compared under the same conditions as in Example 1, except that the circulation device was shut off, that is, the liquid passing through the chromatography column was directly discharged, and the flow rate and the mass hourly space velocity of the liquid were reduced to 0.05 L / (g·h) to ensure that the operation time was the same as in Example 1.

[0128] The evaluation results are listed in Table 1.

[0129] Table 1. Metal ion capture efficiency of each embodiment and comparative example.

[0130]

[0131] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for capturing and detecting metal ions in water, comprising the following steps: S1. Take a water sample containing metal ions as the test solution; S2. The adsorbent material is loaded into the chromatography column to form the adsorption layer. The test solution passes through the chromatography column for adsorption. The adsorbed liquid is then recycled back into the chromatography column. S3. Detect the adsorbed metal ions and calculate the capture rate.

2. The method according to claim 1, characterized in that, In step S1, the metal ions contained in the test solution include non-radioactive metal ions and / or radioactive metal ions; the non-radioactive metal ions are preferably at least one of Cs, Co, and Mn; the radioactive metal ions are preferably at least one of radioactive Cs, radioactive Co, and radioactive Mn.

3. The method according to claim 2, characterized in that, In step S1, the concentration of non-radioactive metal ions in the test solution is 0.01–50 mg / L, preferably 0.05–30 mg / L; And / or, in step S1, the volume activity of the radioactive metal ions in the test solution is 0.001 to 50 Bq / L.

4. The method according to claim 1, characterized in that, In step S2, the solid-liquid ratio of the adsorbent material and the test liquid is 0.02–1 g / L, preferably 0.05–0.5 g / L; And / or, in step S2, the adsorbent material is selected from at least one of ammonium phosphomolybdate, ammonium phosphomolybdate-polyacrylonitrile, layered sulfide, and SCM-IC-1 molecular sieve composite material, preferably SCM-IC-1 molecular sieve composite material.

5. The method according to claim 4, characterized in that, The SCM-IC-1 molecular sieve composite material comprises a porous silicon-aluminum crystal component, an ammonium phosphomolybdate component, and a silicon-based binder component; And / or, the structure of the silica-alumina porous crystal component has one or more of the topological structures of MWW, FAU, BEA, MOR, ATS, CHA, and MFI molecular sieves.

6. The method according to claim 5, characterized in that, Based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the silica-alumina porous crystal component is 8-30%. And / or, based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the ammonium phosphomolybdate component is 20-65%; And / or, based on the mass of the SCM-IC-1 molecular sieve composite material, the mass content of the silicon-based binder component is 25% to 50%.

7. The method according to claim 1, characterized in that, In step S2, the test solution is adsorbed through a chromatography column. The operating parameters include: the operating temperature is 5-40℃, preferably 10-35℃; the mass hourly space velocity (MHV) of the test solution is 0.02-5 L / (g·h), preferably 0.03-3 L / (g·h); wherein, the MHV is the volume of test solution injected per hour relative to the adsorbent material. And / or, in step S2, the cycle ends after the target capture rate is reached, and the adsorption time is 1 to 150 hours, preferably 1 to 120 hours.

8. The method according to claim 1 or 2, characterized in that, In step S3, when the metal ions to be captured are non-radioactive metal ions, the test solution after adsorption in S2 needs to be detected and the capture rate calculated. And / or, in step S3, when the metal ions to be captured are radioactive metal ions, it is necessary to use γ-rays to determine the amount of radioactive particles in the adsorption layer and calculate the capture rate of radioactive metal ions. And / or, in step S3, the operation steps of the γ-ray measurement are as follows: the adsorption layer is placed in the cavity of the γ-ray tester, tested for 5 to 20 hours, the number of decaying particles is recorded, the relative decay constant is calculated to determine the total number of radioactive particles, and thus the collection efficiency of the adsorption material provided by the present invention for radioactive ions is calculated.

9. A device for capturing and detecting metal ions in water, comprising an initial water tank, a chromatography column, a liquid pump, and optionally a gamma-ray detector; in, The initial water tank is connected to the upper inlet of the chromatography column, the lower outlet of the chromatography column is connected to the upper inlet of the liquid pump, and the lower outlet of the liquid pump is connected to the initial water tank containing the sample to be tested.

10. The collection and detection device according to claim 9, characterized in that, The inner diameter of the chromatography column is between 8 and 30 mm, and its height is between 5 and 30 cm. The column body is made of a transparent, weakly γ-ray absorbing material, preferably selected from at least one of polystyrene, polypropylene, polycarbonate, polyamide, and inorganic glass.

11. The collection and detection device according to claim 9, characterized in that, The liquid pump is a device that provides power to the liquid and controls the liquid flow rate, preferably a rotary pump.

12. The collection and detection device according to claim 9, characterized in that, The gamma-ray detector has a detection cavity of not less than 2L, preferably 2 to 5L.

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