Method for large-scale preparation of high-stability cesium removal adsorbent and product and application thereof

Abstract

This invention relates to a method for the large-scale preparation of highly stable cesium removal adsorbents, as well as their products and applications. Specifically, this invention relates to a particulate inorganic oxide or activated carbon supported transition metal-stabilized ferrocyanide adsorbent, comprising: a particulate inorganic oxide support or a particulate activated carbon support; a transition metal-stabilized ferrocyanide layer coating the inorganic oxide or activated carbon support; and a polymer material layer coating the transition metal-stabilized ferrocyanide layer. This adsorbent exhibits high crushing strength and low ion leaching rate. This invention also relates to a method for preparing this adsorbent and its applications in removing radioactive isotope Cs ions and stable isotope Cs ions, as well as in removing radioactive isotope Rb ions and stable isotope Rb ions.

Description

[0001] This application is a divisional application of the invention patent application filed on January 4, 2018, with application number 201810008565.2 and invention title "Large-scale preparation method of highly stable cesium removal adsorbent and its products and applications". Technical Field

[0002] This invention relates to the field of inorganic materials, and in particular to a method for the large-scale preparation of a highly stable cesium adsorbent, its products and applications, which also exhibits good adsorption performance for rubidium. Background Technology

[0003] According to China's medium- and long-term nuclear power development plan, by 2020, the installed capacity of operating nuclear power will reach 58 million kilowatts, with approximately 30 million kilowatts under construction; and by 2030, the goal of building a strong nuclear power nation will be fully realized. Faced with new circumstances and challenges in the development of the nuclear energy industry, China urgently needs to vigorously develop areas such as radioactive waste treatment, nuclear emergency technology, and standards for the discharge of radioactive effluents.

[0004] The efficient and timely handling of radioactive liquids is one of the crucial issues that urgently needs to be addressed in establishing a nuclear safety defense-in-depth system. Therefore, there is an urgent need to develop and stockpile new technologies, equipment, and materials for emergency waste treatment, establishing a multi-layered technical guarantee for waste treatment and disposal within nuclear power plants. The first layer is the actual elimination of radionuclides during normal nuclear power plant operation. This technology primarily targets the removal of radioactive waste during normal operation, ensuring the stability and effectiveness of the treatment process while minimizing waste volume. The second layer involves timely on-site emergency treatment of waste liquids when problems such as fuel damage occur, given the wide range and diverse forms of nuclides in the waste liquid. This technology can remove contamination promptly, quickly, and efficiently, preventing the leakage of radioactive materials. The third layer is the last line of defense in the defense-in-depth system: in the extreme case of an accident exceeding design baselines, rapidly initiating off-site nuclear emergency response to minimize the environmental impact of the nuclear accident.

[0005] Compared to ion exchange resins, inorganic ion adsorbents exhibit high selectivity for major trace radionuclides such as Cs, Sr, Co, Ag, and I. They can efficiently remove target radionuclide ions from high-salinity radioactive wastewater, rapidly and significantly reducing the radioactivity of the waste liquid. Furthermore, they are less affected by coexisting non-radioactive ions, resulting in a longer service life and generating only a small amount of solid waste. In addition, the large concentration of radioactive elements in a small volume of solid inorganic ion exchanger makes radiation protection relatively easier. Compared to the waste resin produced by adsorption, the radioactive waste generated by inorganic adsorption technology has better thermal and chemical stability, stronger radiation resistance, and is less prone to radiation or biodegradation, facilitating subsequent treatment and disposal. It also offers greater long-term safety during long-term storage in underground disposal sites. Moreover, wastewater deep purification devices based on inorganic adsorption technology have a simple structure and possess the technical characteristics of effectiveness, high selectivity, miniaturization, modularity, and high mobility. They have low requirements for on-site service conditions and are very suitable for the special requirements of nuclear power plants with complex radioactive waste liquid compositions and limited on-site space.

[0006] Due to the high efficiency, speed, and selectivity of inorganic adsorbents, inorganic adsorption technology plays a crucial role in the treatment of nuclear power plant accident wastewater. Taking the treatment of a specific accident wastewater as a prime example, from the initial establishment of the radioactive wastewater treatment system to its gradual improvement during operation, a process route combining inorganic adsorption and membrane technology was consistently maintained. Inorganic adsorption was used to selectively remove the main radionuclides Cs-134 and Cs-137, significantly reducing the radioactivity level of the wastewater and lowering the radiation protection requirements of subsequent processes. Furthermore, membrane technology was employed to broadly remove radionuclides from the water. According to the provided water quality monitoring results, after treatment using the Cs adsorption and reverse osmosis process, the radioactivity level of the water sample decreased from the initial 10... 7 -10 8 The Bq / L level (which was higher in the initial period after the accident) decreased to 10. 3 -10 4The level of Bq / L. Inorganic adsorbents have also been widely used in the normal operation of nuclear power plants. For example, the Loviisa and Paks power plants in Finland and Hungary use cesium-removing adsorbents to further reduce the volume of evaporator waste liquid; the Dunley power plant in Scotland uses inorganic adsorbents to selectively remove Cs-134 and Cs-137 from 1,500 tons of Na-cooled reactor waste liquid and 57 tons of Na / K-cooled reactor high-salinity waste liquid; the Bradwell Magnox power plant in the UK uses inorganic adsorbents to treat acidic dissolution liquid of fuel element debris during the decommissioning process; the Japan Atomic Energy Research Institute (JAERI) uses inorganic adsorbents to remove Pu / Cs / Sr from concentrated nitric acid dissolution waste liquid; and the Savannah River and Callaway nuclear power plants in the United States, the Sellafield nuclear power plant in the United Kingdom, and the Olkiluoto nuclear power plant in Finland all use inorganic adsorbents to treat waste liquid from spent fuel storage pools.

[0007] Over the past few decades, research on inorganic adsorbents for cesium removal has been limited. These mainly include, for example, zirconium pyrophosphate (Chinese invention patent CN106342077B from the China Institute of Atomic Energy); inorganic composite adsorbents composed of non-metallic minerals through appropriate processing (Chinese invention patent CN103691393B from the Beijing Research Institute of Nuclear Geology); magnetic cesium selective adsorbents (Chinese invention patent CN104054136 from Genesis Electric Co., Ltd. of Japan and Chinese invention patent CN1129922C from the China Institute of Atomic Energy); and the ferrocyanide series of inorganic adsorbents for cesium removal successfully developed by our research group. These adsorbents exhibit excellent performance in treating emergency radioactive wastewater from nuclear power plants and have been granted several Chinese national patents, such as CN100469435C, CN101279249B, and CN102836693B.

[0008] The AP1000 reactor currently under construction in my country is designed to selectively remove Cs-134 and Cs-137 from process water using inorganic adsorbents. Process water mainly includes core cooling water and nuclear fuel storage pool cooling water used during normal nuclear power plant operation. Most operating nuclear power plants in my country employ nuclear-grade water filters and ion exchange desalination beds for this purpose. Filters with different filtration calibers are installed before and after the desalination bed. The pre-filter removes particulate matter from the waste liquid, protecting the desalination bed, while the post-filter primarily removes waste resin particles generated by the desalination bed, ensuring the cleanliness of the effluent. The operation of the power plant places extremely high demands on the quality of the process water. For example, it requires extremely low conductivity and ion concentration to inhibit metal corrosion and ensure the safe operation of the reactor, and extremely low turbidity to prevent filter clogging during treatment, extend filter life, and reduce solid waste. In the AP1000 process water treatment design, flocculation combined with activated carbon filtration is used to remove colloids from the waste liquid. Then, inorganic adsorbents are used to remove the main nuclides Cs-134 and Cs-137, followed by ion exchange resins to remove other nuclides. This removal process is designed to improve nuclide treatment efficiency and reduce the generation of radioactive waste resin. Currently, the inorganic adsorbent used in the AP1000 design is zeolite, which exhibits slow adsorption rates and is prone to pulverization, leading to increased turbidity and conductivity in the water.

[0009] In view of the above, providing high-strength and high-stability inorganic adsorbents that can efficiently remove cesium ions from process water under normal operating conditions of nuclear power plants remains one of the urgent problems to be solved. Summary of the Invention

[0010] One objective of this invention is to provide a high-strength, high-stability particulate cesium removal adsorbent and to achieve efficient removal of Cs-134 and Cs-137 from process water under normal operating conditions in nuclear power plants.

[0011] Through extensive experimentation, the inventors of this invention unexpectedly discovered that by washing away the loose solid particles and soluble ions bound to the surface of a particulate inorganic oxide or activated carbon-supported transition metal-stabilized ferrocyanide adsorbent, and then coating it with a polymer material layer, a cesium removal adsorbent with mechanical stability and low ion permeation rate can be obtained.

[0012] On one hand, the present invention provides a transition metal-stabilized ferrocyanide adsorbent supported by particulate inorganic oxides or particulate activated carbon, comprising: particulate inorganic oxides or particulate activated carbon as a carrier; a transition metal-stabilized ferrocyanide layer coating the inorganic oxide or activated carbon carrier; and a polymer material layer coating the transition metal-stabilized ferrocyanide layer.

[0013] Preferably, the polymeric material includes sodium alginate, chitosan, polyethylene glycol with a number average molecular weight between 2000 and 6000, polyvinyl alcohol, sucrose, or any combination thereof.

[0014] Preferably, the adsorbent according to the invention has a crushing strength of 2-100 N / particle.

[0015] Preferably, the adsorbent according to the invention has such ion leaching properties that after soaking the adsorbent at a liquid-to-solid ratio of 10 for 24 hours, the turbidity of the resulting leachate is less than 10 mg / L.

[0016] Preferably, the adsorbent according to the invention has such ion leaching properties that after soaking the adsorbent at a liquid-to-solid ratio of 10 for 24 hours, the conductivity of the resulting leachate is less than 15 mg / L.

[0017] The resulting adsorbent can efficiently remove Cs-134 and Cs-137 from process water under normal operating conditions in nuclear power plants. This adsorbent can be applied not only to AP1000 reactors but also to various pressurized water reactors both domestically and internationally, to reduce the emission of the major nuclides Cs-134 and Cs-137, decrease the amount of ion exchange resin used, and achieve the goal of waste minimization. Furthermore, the adsorbent also exhibits good adsorption performance for the radioactive isotopes Rb-88 and Rb-89 present in radioactive waste liquids.

[0018] On the other hand, the present invention also relates to a method for preparing the above-mentioned particulate inorganic oxide or particulate activated carbon supported transition metal stabilized ferrocyanide adsorbent, comprising:

[0019] 1) Provide primary adsorbent;

[0020] 2) Wash the primary adsorbent from step 1) with deionized water until the conductivity of the washing solution is 25.0 μS / cm or lower and the turbidity is 30 mg / L or lower; and

[0021] 3) Coating the washed primary adsorbent with a polymer material, preferably in the presence of an acid or alkali, to obtain a coated primary adsorbent; and

[0022] 4) Optionally, the coated primary adsorbent from step 3) is washed with deionized water until the conductivity of the washing solution is 20.0 μS / cm or lower and the turbidity is 20 mg / L or lower.

[0023] Thus, the particulate inorganic oxide or particulate activated carbon supported transition metal-stabilized ferrocyanide adsorbent is obtained.

[0024] Preferably, according to one embodiment of the present invention, the step of providing the primary adsorbent includes immersing a particulate inorganic oxide or particulate activated carbon support in an aqueous solution of ferrocyanide for 2-48 hours to obtain a precursor A loaded with ferrocyanide, then mixing the precursor A with an aqueous solution of a transition metal salt and reacting it in a sealed reaction vessel at a temperature of 100-150°C for 2-24 hours.

[0025] Preferably, according to one embodiment of the present invention, the step of providing the primary adsorbent includes immersing a particulate inorganic oxide or particulate activated carbon support in an aqueous solution of a transition metal salt for 2-48 hours to obtain a precursor B loaded with a transition metal salt, then mixing the precursor B with an aqueous solution of ferrocyanide and reacting it in a sealed reaction vessel at a temperature of 100-150°C for 2-24 hours.

[0026] In one specific embodiment of the present invention, the adsorbent according to the present invention is prepared by comprising the following steps:

[0027] (1) Loading of ferrocyanide: First, add pure water to reactor No. 1 and heat it to 80-100℃. Add soluble ferrocyanide to it and let it dissolve. Then, add particulate inorganic oxide support or particulate activated carbon support to the reactor and impregnate for 2-48 hours. After that, perform solid-liquid phase separation and dry to obtain precursor A loaded with ferrocyanide.

[0028] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, add pure water to reactor No. 2 and heat it to 80-100℃. Add soluble transition metal salt to dissolve it. Then, add the precursor A loaded with ferrocyanide obtained in step (1) to the reactor. After stirring evenly, seal the reactor and set the reaction temperature at 100-150℃ for 2-24 hours. After the reaction is completed, perform solid-liquid phase separation to obtain the primary cesium removal adsorbent B.

[0029] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent B obtained in step (2) is cleaned with deionized water for 10 hours or longer, until the conductivity of the washing liquid is 25.0 μs / cm or lower and the turbidity is 30.0 mg / L or lower. The obtained adsorbent is then dried, preferably in a constant temperature oven or vacuum oven at a drying temperature of 60-120°C, and is referred to as secondary adsorbent C.

[0030] (4) Adsorbent coating: The secondary adsorbent C obtained in step (3) is coated with a polymer material layer as follows: the polymer material with bonding effect is dissolved in pure water to prepare a solution of a certain concentration; the secondary adsorbent C is added to the solution system; depending on the polymer material, acid or alkali solution is added dropwise during stirring; after stirring the mixture for 1-10 hours, solid-liquid phase separation is performed to obtain the tertiary adsorbent D.

[0031] (5) Cleaning of the adsorbent: The tertiary cesium removal adsorbent D obtained in step (4) is cleaned with deionized water for 10 hours or longer, until the conductivity of the washing liquid is 20.0 μs / cm or lower and the turbidity is 20 mg / L or lower. After that, solid-liquid phase separation is performed and the adsorbent is dried, preferably in a constant temperature oven or vacuum oven at a drying temperature of 60-120°C, to obtain the final cesium removal adsorbent E.

[0032] Furthermore, according to the present invention, the ferrocyanide used is soluble, including potassium ferrocyanide and sodium ferrocyanide. Preferably, the concentration of the aqueous solution of the soluble ferrocyanide is 10–50 wt%.

[0033] Furthermore, according to the present invention, the particulate inorganic oxide carrier includes silica gel microspheres, alumina microspheres, titanium dioxide microspheres, zirconium oxide microspheres, and molecular sieve microspheres. Preferably, the particle size of the microspheres is 0.5–5 mm, and their crushing strength is 2–150 N / particle.

[0034] Furthermore, according to the present invention, the granular activated carbon carrier can be coal-based carbon, or coconut shell carbon, fruit shell carbon, etc. Preferably, the particle size of the activated carbon particles is about 0.5 to 5 mm, and its crushing strength is 2-150 N / particle.

[0035] Furthermore, according to the present invention, the transition metal salt is soluble, including copper sulfate, copper nitrate, copper chloride, ferrous sulfate, ferric nitrate, nickel nitrate, nickel sulfate, zinc chloride, zinc sulfate, zinc acetate, cobalt nitrate, cobalt chloride, zirconium oxychloride, manganese sulfate, or any combination thereof. Preferably, the concentration of the aqueous solution of the above-mentioned soluble salt is 10–60 wt%.

[0036] Furthermore, according to the present invention, the polymeric materials used include sodium alginate, chitosan, polyethylene glycol (2000-6000), polyvinyl alcohol, sucrose, or combinations thereof. Preferably, the above-mentioned polymeric materials are prepared as an aqueous solution with a concentration of 1-20 wt%.

[0037] Furthermore, according to the present invention, the acid added dropwise is hydrochloric acid, sulfuric acid, acetic acid, or any combination thereof. Preferably, the concentration of the acid is 0.01 to 1 mol / L.

[0038] Furthermore, according to the present invention, the added alkali is sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonia, or any combination thereof. Preferably, the concentration of the alkali is 0.01–1 mol / L;

[0039] The series of particle-supported ferrocyanide adsorbents prepared by the above preparation method are also within the scope of protection of this invention.

[0040] The inventors of this invention have surprisingly discovered that the granular inorganic oxide or granular activated carbon-supported transition metal-stabilized ferrocyanide adsorbent according to the present invention possesses structural stability and high adsorption performance. This adsorbent has broad application prospects because it can adsorb both radioactive and / or stable isotope Cs ions and radioactive and / or stable isotope Rb ions. For example, it can be used to separate and / or remove or extract radioactive or stable isotope Cs ions through adsorption, and also for the separation and / or removal or extraction of radioactive or stable isotope Rb ions. Therefore, the applications of the granular inorganic oxide or granular activated carbon-supported transition metal-stabilized ferrocyanide adsorbent according to the present invention in removing radioactive and stable isotope Cs ions, as well as in removing radioactive and stable isotope Rb ions, are also within the scope of protection of this invention.

[0041] The inventors of this invention recognized that a water washing process on a primary adsorbent using inorganic oxides or activated carbon as a carrier and having a series of transition metal-stabilized ferrocyanide layers on the carrier surface (achieved through a two-step reaction of impregnation and high-temperature hydrothermal treatment) can remove loosely bound solid particles from the surface of the primary adsorbent and fully release soluble ions from the primary adsorbent, resulting in a washed primary adsorbent with good mechanical strength and low ion leaching characteristics. Furthermore, coating the washed primary adsorbent with a polymer layer can further improve its mechanical strength, thereby obtaining an adsorbent preferably with a crushing strength of 2-100 N / particle and extremely low ion leaching characteristics. Detailed Implementation

[0042] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials and standard chemical reagents used for testing can be obtained from publicly available commercial sources unless otherwise specified.

[0043] In the following examples, the adsorbent was subjected to static adsorption and fixed-bed adsorption reaction column performance tests, and the Cs before and after adsorption were measured. + The concentration of ions was determined using inductively coupled plasma mass spectrometry (ICP-MS), and the adsorbent performance was measured using the partition coefficient K. dIt is represented by the decontamination coefficient DF.

[0044] In static adsorption assays, a certain amount of adsorbent is added to a 50 mL centrifuge tube and placed on a constant-temperature shaker for 48–72 hours. The Cs concentrations before and after adsorption are then measured. + Ion concentration and adsorbent performance are expressed using the partition coefficient K. d The adsorption partition coefficient K is expressed as the decontamination coefficient DF. d (mL / g) is shown in Formula 1 below, where C0 and C t These represent the initial concentration of the adsorbed ions and the concentration after adsorption equilibrium, respectively. F is the ratio of the volume of the treated solution (mL) to the mass of the adsorbent (mg). The decontamination coefficient is shown in Equation 2 below, which is the ratio of the influent concentration of adsorbed ions to the effluent concentration after adsorption equilibrium. Generally, the adsorption partition coefficient describes the characteristics of the adsorbent material itself, K. d Value at 10 5 The above demonstrates that the adsorbent performs well; the decontamination coefficient is related not only to the adsorption characteristics of the material itself, but also to the amount of adsorbent used. The larger the value, the cleaner the pollutants are removed.

[0045] K d =(C o –C t )×F×1000 / C t (1)

[0046]

[0047] Dynamic adsorption performance was assessed using a fixed-bed adsorption reaction column with a height of 10 cm, a diameter of 1.5 cm, and a water flow rate of 20 BV / h. The decontamination factor (DF) was used to represent the adsorption column's effect on Cs. + Its stain removal effect.

[0048] The crushing strength of the adsorbent according to the present invention is determined as follows. The crushing strength of the adsorbent is determined using a domestically produced crushing strength tester, model YHKC-2A particle strength tester. During the test, 60-100 adsorbent particles are randomly selected. Each particle is placed one by one at the center directly below the crushing hammer. The handle is rotated to lower the hammer. As the hammer approaches the particle, it is slowly rotated to allow it to gradually contact the particle. When the sound of the particle breaking is heard, the instrument displays the force (in Newtons) applied to the particle at the moment of crushing. The ion leaching characteristics of the adsorbent according to the present invention are determined as follows: First, the adsorbent is soaked in 10 times its volume of pure water. The solution is stirred using a stirrer or a shaker. After a certain period, the turbidity and conductivity of the soaking liquid are measured using a HACH 2100N turbidimeter and a DDSJ-308A conductivity meter, respectively. The turbidimeter has an accuracy of 0.001 mg / L, and the conductivity meter has an accuracy of 0.01 μS / cm.

[0049] Example 1: Preparation and Cesium Removal Performance of Silica Gel Supported Adsorbent

[0050] Silica gel with high mechanical strength and a particle size of 0.5-2.0 mm was selected, and potassium copper ferrocyanide adsorbent was prepared on it. The steps are as follows:

[0051] (1) Copper salt loading: First, pure water was added to reactor No. 1 and heated to 80-100℃. Copper sulfate was added to it and dissolved to form a solution with a concentration of 10-50%. Then, silica gel particles Si-1 were added to the reactor as a carrier and impregnated for 2-48 hours. After solid-liquid phase separation and drying, the precursor Si-1-A loaded with copper sulfate was obtained.

[0052] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, pure water was added to reactor No. 2 and heated to 80-100℃. Sodium ferrocyanide was added to dissolve it and form a solution with a concentration of 10-50%. Then, the copper sulfate-loaded precursor Si-1-A obtained in step (1) was added to the reactor. After stirring evenly, the reactor was sealed and the reaction temperature was set at 100℃ for 24 hours. After the reaction was completed, solid-liquid phase separation was performed to obtain the primary cesium removal adsorbent Si-1-B.

[0053] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent Si-1-B obtained in step (2) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. After continuous stirring for 24 hours, the conductivity of the washing liquid was 22.8 μs / cm and the turbidity was reduced to 17.8 mg / L. The obtained adsorbent was then dried and recorded as the secondary adsorbent Si-1-C.

[0054] (4) Adsorbent coating: The secondary adsorbent Si-1-C obtained in step (3) is coated with a polymer layer. The method is to use chitosan as a binder. First, chitosan is dissolved in pure water to prepare a solution with a concentration of 2-10 wt%. The secondary adsorbent Si-1-C is added to the solution system. After stirring for 1 hour, 1.0 M sodium hydroxide solution is gradually added to the system until the pH value of the solution reaches 10-11. After stirring and reacting for 5-10 hours, the solid and liquid phases are separated to obtain the tertiary adsorbent Si-1-D.

[0055] (5) Cleaning of the adsorbent: The three-stage cesium removal adsorbent Si-1-D obtained in step (4) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. The cleaning was continued until the turbidity of the washing liquid after continuous stirring for 24 hours was less than 20 mg / L and the conductivity was less than 20 μs / cm. Then the solid and liquid phases were separated and the adsorbent was dried under vacuum to obtain the final silica gel supported copper potassium ferrocyanide cesium removal adsorbent.

[0056] The crushing strength of the adsorbent was measured to be 12–14 N / particle. After soaking for 24 hours at a liquid-to-solid ratio of 10, the turbidity in the liquid was 6 mg / L, the conductivity was 11 μS / cm, and the COD concentration was 1.5 mg / L. Using the static adsorption method to determine the adsorption performance, with an initial Cs ion concentration of 10 mg / L, a coexisting boric acid concentration of 500 mg / L (boron), a test liquid volume of 50 mL, and an adsorbent mass of 10 mg, the decontamination factor (DF) for Cs was 26.2, equivalent to a Cs removal rate greater than 95%.

[0057] Example 2: Preparation of alumina-supported adsorbent and its cesium removal performance

[0058] Alumina microspheres (Al-1) with high mechanical strength and a particle size of 0.5-2.0 mm were selected for preparation of potassium zinc ferrocyanide adsorbent on them, as follows:

[0059] (1) Loading of ferrocyanide: First, pure water was added to reactor No. 1 and heated to 80-100℃. Potassium ferrocyanide was added to the reactor to dissolve it and form a solution with a concentration of 10-50%. Then, alumina microspheres Al-1 were added to the reactor as a carrier and impregnated for 2-48 hours. After solid-liquid phase separation, the mixture was dried in a constant temperature oven to obtain the precursor Al-1-A loaded with ferrocyanide.

[0060] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, add pure water to reactor No. 2 and heat it to 80-100℃. Add zinc acetate to it to dissolve and form a solution with a concentration of 10-50%. Then, add the ferrocyanide-loaded precursor Al-1-A obtained in step (1) to the reactor. After stirring evenly, seal the reactor and set the reaction temperature at 100℃ for 8-16 hours. After the reaction is completed, perform solid-liquid phase separation to obtain the primary cesium removal adsorbent Al-1-B.

[0061] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent Al-1-B obtained in step (2) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. After continuous stirring for 24 hours, the conductivity of the washing liquid was 18.2 μs / cm and the turbidity was reduced to 21.3 mg / L. The obtained adsorbent was then dried and recorded as the secondary adsorbent Al-1-C.

[0062] (4) Adsorbent Coating: The secondary adsorbent Al-1-C obtained in step (3) is coated with a polymer layer. The method is to use polyvinyl alcohol and polyethylene glycol (6000) as binders. First, polyvinyl alcohol and polyethylene glycol are dissolved in pure water to prepare solutions. The concentration of polyvinyl alcohol solution is 1-10 wt%, and the concentration of polyethylene glycol (6000) is 5-30%. The secondary adsorbent Al-1-C is added to the solution system with a liquid-solid ratio of 10:1. After stirring and reacting for 2-10 h, the solid and liquid phases are separated to obtain the tertiary adsorbent Al-1-D.

[0063] (5) Cleaning of the adsorbent: The three-stage cesium removal adsorbent Al-1-D obtained in step (4) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. The cleaning was continued until the turbidity of the washing liquid after continuous stirring for 24 hours was less than 20 mg / L and the conductivity was less than 20 μs / cm. Then the solid and liquid phases were separated and the adsorbent was dried under vacuum to obtain the final alumina-supported zinc ferrocyanide potassium cesium removal adsorbent.

[0064] The crushing strength of the adsorbent was measured to be 3–9 N / particle. After soaking for 24 hours at a liquid-to-solid ratio of 10, the turbidity in the liquid was 3 mg / L, the conductivity was 7 μS / cm, and the COD concentration was 2.7 mg / L. Using the static adsorption method to determine the adsorption performance, with an initial Cs ion concentration of 10 mg / L, a coexisting boric acid concentration of 500 mg / L (boron), a test liquid volume of 50 mL, and an adsorbent mass of 10 mg, the decontamination factor (DF) for Cs was 23.2, equivalent to a Cs removal rate greater than 95%.

[0065] Further dynamic measurements were conducted using a fixed-bed small adsorption column. The column was 10 cm high and 1.5 cm in diameter, filled entirely with adsorbent, and the water flow rate was 20 BV / h. The initial concentration of Cs was 10 mg / L. The results showed that the adsorbent maintained a Cs removal coefficient of 330 even when the water flow rate reached 3870 BV.

[0066] Example 3: Preparation and Performance of Titanium Oxide Supported Adsorbent

[0067] Titanium oxide microspheres (Ti-1) with high mechanical strength and a particle size of 0.5-2.0 mm were selected for preparation of potassium cobalt ferrocyanide adsorbent on them, as follows:

[0068] (1) Loading of ferrocyanide: First, pure water was added to reactor No. 1 and heated to 80-100℃. Potassium ferrocyanide was added to it and dissolved to form a solution with a concentration of 10-50%. Then, titanium dioxide microspheres Ti-1 were added to the reactor as a carrier and impregnated for 2-48h. After solid-liquid phase separation, the mixture was dried in a constant temperature oven to obtain the precursor Ti-1-A loaded with ferrocyanide.

[0069] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, add pure water to reactor No. 2 and heat it to 80-100℃. Add cobalt nitrate to dissolve it and form a solution with a concentration of 10-50%. Then, add the ferrocyanide-loaded precursor Ti-1-A obtained in step (1) to the reactor. After stirring evenly, seal the reactor and set the reaction temperature at 100℃ for 4-12 hours. After the reaction is completed, perform solid-liquid phase separation to obtain the primary cesium removal adsorbent Ti-1-B.

[0070] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent Ti-1-B obtained in step (2) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. After continuous stirring for 24 hours, the conductivity of the washing liquid was 22.4 μs / cm and the turbidity was reduced to 15.8 mg / L. The obtained adsorbent was then dried and recorded as the secondary adsorbent Ti-1-C.

[0071] (4) Adsorbent Coating: The secondary adsorbent Al-1-C obtained in step (3) is coated with a polymer layer. The method is to use polyvinyl alcohol + sucrose and polyethylene glycol + sucrose (6000) as binders respectively. First, polyvinyl alcohol and polyethylene glycol are dissolved in pure water to prepare solutions. The concentration of polyvinyl alcohol solution is 1-10 wt%, and the concentration of polyethylene glycol (6000) is 5-30%. Then, sucrose is added to the solution to dissolve it, and the concentration of sucrose to polyvinyl alcohol or polyethylene glycol is controlled to be 1-4 times. The secondary adsorbent Ti-1-C is added to the solution system with a liquid-solid ratio of 10:1. After stirring and reacting for 2-10 hours, the solid and liquid phases are separated to obtain the tertiary adsorbent Ti-1-D.

[0072] (5) Cleaning of the adsorbent: The three-stage cesium removal adsorbent Al-1-D obtained in step (4) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. The cleaning was continued until the turbidity of the washing liquid after continuous stirring for 24 hours was less than 20 mg / L and the conductivity was less than 20 μs / cm. Then the solid and liquid phases were separated and the adsorbent was dried under vacuum to obtain the final alumina-supported zinc ferrocyanide potassium cesium removal adsorbent.

[0073] The crushing strength of the adsorbent was measured to be 3–9 N / particle. After soaking for 24 hours at a liquid-to-solid ratio of 10, the turbidity in the liquid was 2 mg / L, the conductivity was 6 μS / cm, and the COD concentration was 1.6 mg / L. Using the static adsorption method to determine the adsorption performance, with an initial Cs ion concentration of 10 mg / L, a coexisting boric acid concentration of 500 mg / L (boron), a test liquid volume of 50 mL, and an adsorbent mass of 10 mg, the decontamination factor (DF) for Cs was 26.7, equivalent to a Cs removal rate greater than 95%.

[0074] Further dynamic measurements were conducted using a fixed-bed small adsorption column. The column was 10 cm high and 1.5 cm in diameter, filled entirely with adsorbent, and the water flow rate was 20 BV / h. The initial concentration of Cs was 10 mg / L. The results showed that the adsorbent maintained a Cs removal coefficient of 310 even when the water flow rate reached 4213 BV.

[0075] Example 4: Preparation of Zirconia-supported adsorbent and its adsorption performance for rubidium and cesium.

[0076] Zirconia microspheres (Zr-1) with a monoclinic crystal phase were selected as the adsorbent carrier. The microspheres had a particle size of 0.5-2.0 mm and possessed high mechanical strength, with a crushing strength greater than 30 N / particle. Potassium ferrocyanide (III) adsorbent was prepared on these microspheres using the following steps:

[0077] (1) Loading of ferrocyanide: First, pure water was added to reactor No. 1 and heated to 80-100℃. Sodium ferrocyanide was added to it and dissolved to form a solution with a concentration of 10-50%. Then, zirconium oxide microspheres Zr-1 were added to the reactor as a carrier and impregnated for 10-48h. After that, solid-liquid phase separation was carried out and the mixture was dried in a constant temperature oven to obtain the precursor Zr-1-A loaded with ferrocyanide.

[0078] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, pure water was added to reactor No. 2 and heated to 80-100℃. Ferric nitrate was added to dissolve the ferrocyanide and form a solution with a concentration of 10-50%. Then, the precursor Zr-1-A loaded with ferrocyanide obtained in step (1) was added to the reactor. After stirring evenly, the reactor was sealed and the reaction temperature was set at 120℃ for 10-24h. After the reaction was completed, solid-liquid phase separation was performed to obtain the primary cesium removal adsorbent Zr-1-B.

[0079] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent Zr-1-B obtained in step (2) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. After continuous stirring for 24 hours, the conductivity of the washing liquid was 15.6 μs / cm and the turbidity was reduced to 25.8 mg / L. The obtained adsorbent was then dried and recorded as secondary adsorbent Zr-1-C.

[0080] (4) Adsorbent Coating: The secondary adsorbent Zr-1-C obtained in step (3) is coated with a polymer layer. Sodium alginate is used as a binder. First, sodium alginate is dissolved in pure water to prepare a solution with a concentration of 1-10 wt%. The secondary adsorbent Zr-1-C is added to the solution system with a liquid-to-solid ratio of 10:1. After stirring for 1 h, 1 M hydrochloric acid solution is added dropwise until the pH value is 4-5. After stirring and reacting for 2-10 h, the solid and liquid phases are separated to obtain the tertiary adsorbent Zr-1-D.

[0081] (5) Cleaning of the adsorbent: The three-stage cesium removal adsorbent Zr-1-D obtained in step (4) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. The cleaning was continued until the turbidity of the washing liquid after continuous stirring for 24 hours was less than 20 mg / L and the conductivity was less than 20 μs / cm. Then the solid and liquid phases were separated and the adsorbent was dried under vacuum to obtain the final zirconium oxide supported potassium ferrocyanide (Prussian blue) cesium removal adsorbent.

[0082] The crushing strength of the adsorbent was measured to be 41 N / particle. After soaking for 24 hours under a liquid-to-solid ratio of 10, the turbidity in the liquid was 7 mg / L, the conductivity was 12 μs / cm, and the COD concentration in the solution was 1.9 mg / L.

[0083] The competitive adsorption performance of cesium (Cs) with lithium, sodium, potassium, and rubidium (Nd, K, rubidium) was determined using a static adsorption method. The test solution volume was 50 mL, and the adsorbent mass was 10 mg. The boric acid concentration (calculated as boron) in the test solution was 500 ppm, and the initial Cs concentration was 10 mg / L. Two concentrations of coexisting lithium, sodium, potassium, and rubidium ions were used, each equivalent to the same molar ratio as 10 mg / L Cs. The adsorption performance of the adsorbent for Cs was measured under the competitive state of coexisting ions. The adsorption performance of Cs alone was also measured. + In the presence of Li, the decontamination coefficient of the adsorbent for Cs is 23.2, which is higher than that for the same molar amount of Li. + Na + K + 、Rb + Under competitive adsorption, the decontamination coefficients for Cs were 21.6, 11.3, 9.2 and 9.4, respectively.

[0084] Experimental data show that the supported ferrocyanide series adsorbents developed in this invention have certain adsorption characteristics for Group 1 ions, mainly Na+. + K + 、Rb + With Cs + There is some competition between them, but their adsorption performance for Li is very poor. Therefore, the presence of LiOH in nuclear power plant process waste will not affect the adsorption and removal performance of radionuclide Cs. Generally, radionuclide Rb is also present in nuclear power plant process waste. + Therefore, the supported ferrocyanide series adsorbents developed in this invention can simultaneously remove Rb-88, Rb-89, and Cs-134 and Cs-137 from process water.

[0085] Example 4: Preparation of activated carbon supported adsorbent and its cesium adsorption performance

[0086] Coconut shell activated carbon particles with a particle size of 0.5-2.0 mm were selected as the carrier. These particles were washed with pure water until the pH was neutral and the conductivity was <20 μS / cm. Afterward, the activated carbon particles were dried and used as the adsorbent carrier. Measurements showed that the selected activated carbon particles had high mechanical strength, with a crushing strength greater than 20 N / particle. Potassium nickel (II) ferrocyanide adsorbent was prepared on these particles using the following steps:

[0087] (1) Loading of ferrocyanide: First, pure water was added to reactor No. 1 and heated to 80-100℃. Potassium ferrocyanide was added to the reactor and dissolved to form a solution with a concentration of 10-50%. Then, activated carbon particles were added to the reactor as a carrier and impregnated for 10-48 hours. After that, solid-liquid phase separation was performed and the mixture was dried in a constant temperature oven to obtain the precursor GAC-1-A loaded with ferrocyanide.

[0088] (2) Preparation of transition metal-stabilized ferrocyanide adsorbent: First, pure water was added to reactor No. 2 and heated to 80-100℃. Nickel sulfate was added to dissolve it and form a solution with a concentration of 10-50%. Then, the precursor GAC-1-A loaded with ferrocyanide obtained in step (1) was added to the reactor. After stirring evenly, the reactor was sealed and the reaction temperature was set at 120℃ for 10-24h. After the reaction was completed, solid-liquid phase separation was performed to obtain the primary cesium removal adsorbent GAC-1-B.

[0089] (3) Cleaning of the adsorbent: The primary cesium removal adsorbent GAC-1-B obtained in step (2) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. This continued until the conductivity of the washing liquid after continuous stirring for 24 hours was <20 μs / cm and the turbidity decreased by <20 mg / L. The obtained adsorbent was then dried and recorded as secondary adsorbent GAC-1-C.

[0090] (4) Adsorbent coating: The secondary adsorbent GAC-1-C obtained in step (3) is coated with a polymer layer. The method is to use polyvinyl alcohol as a binder. First, polyvinyl alcohol is dissolved in pure water to prepare a solution with a concentration of 1-10 wt%. The secondary adsorbent GAC-1-C is added to the solution system with a liquid-solid ratio of 10:1. After stirring and reacting for 2-10 hours, the solid and liquid phases are separated to obtain the tertiary adsorbent GAC-1-D.

[0091] (5) Cleaning of the adsorbent: The three-stage cesium removal adsorbent GAC-1-D obtained in step (4) was cleaned with pure water. The volume of water used for each cleaning was 10 times the volume of the adsorbent. The cleaning was continued until the turbidity of the washing liquid after continuous stirring for 24 hours was less than 20 mg / L and the conductivity was less than 20 μs / cm. Then the solid and liquid phases were separated and the adsorbent was dried under vacuum to obtain the final granular activated carbon supported nickel potassium ferrocyanide cesium removal adsorbent.

[0092] The crushing strength of the adsorbent was measured to be 32 N / particle. After soaking for 24 hours under a liquid-to-solid ratio of 10, the turbidity in the liquid was 12 mg / L, the conductivity was 18 μs / cm, and the COD concentration in the solution was 1.4 mg / L.

[0093] The adsorption performance of cesium was determined using a static adsorption method. The test solution volume was 40 mL, and the adsorbent mass was 10 mg. The boric acid concentration in the test solution (calculated as boron) was 1000 ppm, and the initial concentration of cesium (Cs) was 10 mg / L. The decontamination coefficient of the adsorbent for Cs was determined to be 48.3.

[0094] The various aspects of the present invention have been explained above by way of specific embodiments. However, those skilled in the art will understand that the present invention is not limited to the specific embodiments described above. Equivalent substitutions and combinations of various specific technical means, raw materials, and process steps disclosed herein by those skilled in the art are all within the scope of the present invention.

[0095] To further illustrate certain aspects of the invention, the invention also provides the following non-limiting embodiments:

[0096] 1. A particulate inorganic oxide or activated carbon supported transition metal-stabilized ferrocyanide adsorbent, comprising: a particulate inorganic oxide support or a particulate activated carbon support; a transition metal-stabilized ferrocyanide layer coating the inorganic oxide or activated carbon support; and a polymer material layer coating the transition metal-stabilized ferrocyanide layer.

[0097] 2. The adsorbent as described in Embodiment 1, wherein the polymer material layer comprises sodium alginate, chitosan, polyethylene glycol with a number average molecular weight between 2000 and 6000, polyvinyl alcohol, sucrose, or any combination thereof.

[0098] 3. The adsorbent as described in Embodiment 1 or 2 has a crushing strength of 2-100 N / particle.

[0099] 4. The adsorbent as described in any one of embodiments 1 to 3 has such ion leaching characteristics that after the adsorbent is soaked for 24 hours at a liquid-to-solid ratio of 10, the turbidity of the resulting liquid is 10 mg / L or lower.

[0100] 5. The adsorbent as described in any one of embodiments 1 to 4 has such ion leaching characteristics that after the adsorbent is soaked for 24 hours at a liquid-to-solid ratio of 10, the conductivity of the resulting liquid is 15 μs / cm or lower.

[0101] 6. The adsorbent according to any one of embodiments 1 to 5, wherein the transition metal-stabilized ferrocyanide layer is formed by reacting a support loaded with ferrocyanide with an aqueous solution of a transition metal salt in a sealed reaction vessel at a temperature of 100-150°C for 2-24 hours, or by reacting a support loaded with a transition metal salt with an aqueous solution of ferrocyanide for 2-24 hours.

[0102] 7. The adsorbent as described in Embodiment 6, wherein the transition metal salt comprises copper sulfate, copper nitrate, copper chloride, ferrous sulfate, ferric nitrate, nickel nitrate, nickel sulfate, zinc chloride, zinc sulfate, zinc acetate, cobalt nitrate, cobalt chloride, zirconium oxychloride, manganese sulfate, or any combination thereof.

[0103] 8. The adsorbent according to any one of embodiments 1 to 7, wherein the carrier has a crushing strength greater than 20 N / particle or greater than 30 N / particle.

[0104] 9. A method for preparing a transition metal-stabilized ferrocyanide adsorbent supported by particulate inorganic oxides or activated carbon, comprising:

[0105] 1) Provide primary adsorbent;

[0106] 2) Wash the primary adsorbent from step 1) with deionized water until the conductivity of the washing solution is 25.0 μs / cm or lower and the turbidity is 30 mg / L or lower.

[0107] 3) Coating the washed primary adsorbent with a polymer material to obtain a coated primary adsorbent; and

[0108] 4) Optionally, the coated primary adsorbent from step 3) is washed with deionized water until the conductivity of the washing solution is 20.0 μS / cm or lower and the turbidity is 20 mg / L or lower.

[0109] Thus, the particulate inorganic oxide or activated carbon-supported transition metal-stabilized ferrocyanide adsorbent is obtained.

[0110] 10. The method according to embodiment 9, wherein the step of providing the primary adsorbent includes immersing a particulate inorganic oxide or particulate activated carbon support in an aqueous solution of ferrocyanide for 2-48 hours to obtain a precursor A loaded with ferrocyanide, then mixing the precursor A with an aqueous solution of a transition metal salt and reacting it in a sealed reaction vessel at a temperature of 100-150°C for 2-24 hours.

[0111] 11. The method according to embodiment 9, wherein the step of providing the primary adsorbent includes immersing a particulate inorganic oxide or particulate activated carbon support in an aqueous solution of a transition metal salt for 2-48 hours to obtain a precursor B loaded with a transition metal salt, then mixing the precursor B with an aqueous solution of ferrocyanide and reacting it in a sealed reaction vessel at a temperature of 100-150°C for 2-24 hours.

[0112] 12. The method according to any one of embodiments 9-11, wherein the polymeric material comprises sodium alginate, chitosan, polyethylene glycol (2000-6000), polyvinyl alcohol, sucrose or a combination thereof, preferably prepared as an aqueous solution with a concentration of 1% to 20 wt%.

[0113] 13. The method according to any one of embodiments 9-12, wherein the step of coating the washed primary adsorbent with a polymeric material is carried out in the presence of an acid or a base.

[0114] 14. The method according to embodiment 13, wherein the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, acetic acid or combinations thereof, preferably having a concentration of 0.01-1 mol / L; the alkali is selected from the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonia or combinations thereof, preferably having a concentration of 0.01-1 mol / L.

[0115] 15. The method according to any one of embodiments 9-14, wherein the particulate inorganic oxide carrier comprises silica gel microspheres, alumina microspheres, titanium oxide microspheres, zirconium oxide microspheres, molecular sieve microspheres or combinations thereof, preferably having a particle size of 0.5 to 5 mm, and / or a crushing strength of 2-150 N / particle, preferably greater than 30 N / particle.

[0116] 16. The method according to any one of embodiments 9-14, wherein the particulate activated carbon carrier comprises coal-based carbon, coconut shell carbon, fruit shell carbon or a combination thereof, preferably having a particle size of 0.5 to 5 mm, and / or a crushing strength of 2-150 N / particle, preferably greater than 20 N / particle.

[0117] 17. The method according to any one of embodiments 9-16, wherein the ferrocyanide comprises potassium ferrocyanide, sodium ferrocyanide or a combination thereof, preferably, the aqueous solution of the ferrocyanide has a concentration of 10-50 wt%.

[0118] 18. The method according to any one of embodiments 9-17, wherein the transition metal salt comprises copper sulfate, copper nitrate, copper chloride, ferrous sulfate, ferric nitrate, nickel nitrate, nickel sulfate, zinc chloride, zinc sulfate, zinc acetate, cobalt nitrate, cobalt chloride, zirconium oxychloride, manganese sulfate, or any combination thereof, preferably, the aqueous solution of the transition metal salt has a concentration of 10-60 wt%.

[0119] 19. A granular inorganic oxide or activated carbon supported metal ion-stabilized ferrocyanide adsorbent prepared by any one of the methods described in embodiments 9-18.

[0120] 20. The use of a granular inorganic oxide or activated carbon supported metal ion stabilized ferrocyanide adsorbent as described in any one of Embodiments 1-8 or as described in Embodiment 19 for adsorbing radioactive isotope Cs ions or adsorbing stable isotope Cs ions.

[0121] 21. The use as described in Embodiment 20, for removing, separating or extracting radioactive isotope Cs ions or for removing, separating or extracting stable isotope Cs ions.

[0122] 22. The use of any one of Embodiments 1-8 or the granular inorganic oxide or activated carbon supported metal ion stabilized ferrocyanide adsorbent described in Embodiment 19 for adsorbing radioactive isotope Rb ions or adsorbing stable isotope Rb ions.

[0123] 23. The use as described in embodiment 22, for removing, separating or extracting radioactive isotope Rb ions or for removing, separating or extracting stable isotope Rb ions.

Claims

1. A particulate inorganic oxide or activated carbon supported transition metal-stabilized ferrocyanide adsorbent, comprising: a particulate inorganic oxide support or a particulate activated carbon support; a transition metal-stabilized ferrocyanide layer coating the inorganic oxide or activated carbon support; and a polymeric material layer coating the transition metal-stabilized ferrocyanide layer. in, The transition metal-stabilized ferrocyanide layer coating the inorganic oxide or activated carbon support is formed as follows: Particulate inorganic oxides or particulate activated carbon carriers are impregnated in an aqueous solution of ferrocyanide at 80-100℃ for 2-48 hours to obtain precursor A loaded with ferrocyanide. Precursor A is then mixed with an aqueous solution of a transition metal salt and reacted in a sealed reactor at 100-150℃ for 2-24 hours; or Particulate inorganic oxides or particulate activated carbon carriers are impregnated in an aqueous solution of transition metal salts at 80-100℃ for 2-48 hours to obtain precursor B loaded with transition metal salts. Precursor B is then mixed with an aqueous solution of ferrocyanide and reacted in a sealed reactor at 100-150℃ for 2-24 hours.

2. The adsorbent as described in claim 1, wherein, The polymer material layer includes sodium alginate, chitosan, polyethylene glycol with a number average molecular weight between 2000 and 6000, polyvinyl alcohol, sucrose, or any combination thereof.

3. The adsorbent as described in claim 1 or 2, having a crushing strength of 2-100 N / particle.

4. The adsorbent as claimed in claim 1 or 2, having such ion leaching properties that after soaking the adsorbent at a liquid-to-solid ratio of 10 for 24 hours, the turbidity of the resulting impregnation solution is 10 mg / L or lower.

5. The adsorbent as claimed in claim 1 or 2, having such ion leaching properties that after soaking the adsorbent at a liquid-to-solid ratio of 10 for 24 hours, the conductivity of the resulting liquid is 15 µs / cm or lower.

6. A method for preparing a transition metal-stabilized ferrocyanide adsorbent supported by particulate inorganic oxides or activated carbon, comprising: 1) Provide primary adsorbent; 2) Wash the primary adsorbent from step 1) with deionized water until the conductivity of the washing solution is 25.0 µs / cm or less and the turbidity is 30 mg / L or less. 3) Coating the washed primary adsorbent with a polymer material and obtaining a coated primary adsorbent in the presence of acid or alkali. as well as 4) Wash the coated primary adsorbent from step 3) with deionized water until the conductivity of the washing solution is 20.0 µS / cm or lower and the turbidity is 20 mg / L or lower. Thus, the particulate inorganic oxide or activated carbon-supported transition metal-stabilized ferrocyanide adsorbent is obtained. The step of providing the primary adsorbent includes impregnating a particulate inorganic oxide or particulate activated carbon carrier in an atmosphere of 80-100 °C. o Precursor A, loaded with ferrocyanide, is obtained by reacting C in an aqueous solution of ferrocyanide for 2-48 hours. Precursor A is then mixed with an aqueous solution of a transition metal salt and reacted in a sealed reactor at 100-150°C for 2-24 hours; or... The step of providing the primary adsorbent includes impregnating a particulate inorganic oxide or particulate activated carbon carrier in an atmosphere of 80-100 °C. o The precursor B, loaded with the transition metal salt, is obtained by reacting the precursor B with an aqueous solution of ferrocyanide for 2-48 hours in a sealed reactor at 100-150°C for 2-24 hours.

7. A particulate inorganic oxide or activated carbon supported transition metal-stabilized ferrocyanide adsorbent prepared by the method of claim 6.

8. The use of any one of claims 1-5 or the particulate inorganic oxide or particulate activated carbon supported transition metal stable ferrocyanide adsorbent as described in claim 7 for adsorbing radioactive isotope Cs ions or adsorbing stable isotope Cs ions, and / or for adsorbing radioactive isotope Rb ions or adsorbing stable isotope Rb ions.

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