WO2019134437A1

WO2019134437A1 - Particulate sb 2o 5 adsorbent, preparation method therefor and use thereof for removing radioactive 90sr and 100mag

Info

Publication number: WO2019134437A1
Application number: PCT/CN2018/114300
Authority: WO
Inventors: 尉继英; 赵璇; 李福志
Original assignee: 清华大学
Priority date: 2018-01-04
Filing date: 2018-11-07
Publication date: 2019-07-11
Also published as: CN108176382A

Abstract

Disclosed are a particulate Sb ₂O ₅ adsorbent, a preparation method therefor and the use thereof for removing radioactive ⁹⁰Sr and ^110mAg. The particulate Sb ₂O ₅ adsorbent contains Sb ₂O ₅ particles; and a high polymer material layer is coated on the Sb ₂O ₅ particles.

Description

Particulate Sb 2O 5 adsorbent and its preparation method and radioactivity removal 90Sr and 100mAg application

Cross-reference to related applications

The present application claims the benefit of the Chinese Patent Application No. 201810008169.X filed on Jan. 4, 20, the entire disclosure of which is hereby incorporated by reference.

Technical field

The invention relates to the field of inorganic materials, in particular to a particulate Sb ₂ O ₅ adsorbent and a preparation method and application thereof, the adsorbent has good adsorption performance for radioactive ⁸⁹ Sr and ⁹⁰ Sr, ^110m Ag, and is suitable for industrial application. The scale can be loaded into a fixed bed reactor to achieve efficient removal of radionuclides.

Background technique

According to China's nuclear power medium- and long-term development planning goals, by 2020, China's nuclear power installed capacity will reach 58 million kilowatts, about 30 million kilowatts under construction; by 2030 to fully realize the goal of building a nuclear power strong country. Faced with the new situation and new challenges in the development of nuclear energy, China urgently needs to develop vigorously in radioactive waste treatment, nuclear emergency technology, and emission standards for radioactive effluents.

In the radioactive waste liquid generated by the daily operation of nuclear power plants, the main sources of radionuclides are activated products and corrosion products. The production of these products is mainly related to the activation, corrosion, precipitation and release behavior of metal materials. Some radionuclides include Ag. , Co, Cr, Mn, Fe, and the like. In the event of fuel damage, the main radioactive materials present in the radioactive waste liquid include not only the long-lived fission products ¹³⁴ Cs/ ¹³⁷ Cs and ⁹⁰ Sr with beta radioactivity, but also ^{110 m} Ag.

⁹⁰ Sr is one of the fission products of ²³⁵ U, with a yield of 5.90% and a half-life of 28 years. It has beta radioactivity. After being absorbed by the body through food or water, 70% to 80% of the dose is excluded. The remaining ⁹⁰ Sr Most of it is deposited in bones and bone marrow, leading to bone cancer, soft tissue cancer and leukemia. Since ⁹⁰ Sr is easy to accumulate in bones, many countries have lower emission limits for ⁹⁰ Sr than ¹³⁷ Cs. Therefore, effective removal of the ⁹⁰ Sr nuclides present in the radioactive waste liquid is an urgent problem to be solved.

There are two main sources of ^110m Ag: First, due to the absorption of neutrons by the control rod Ag-In-Cd alloy, Ag undergoes a homogenous energy transition, forming a metastable ^110m Ag; followed by a silver-containing sealing material. ^110m Ag was formed under neutron activation. Many nuclear power plants in China have observed that their liquid effluent still contains a significant amount of ^110m Ag. The existing radioactive waste liquid treatment technology of the power station has a poor removal effect on ^110m Ag.

Compared with ion exchange resins, inorganic ion adsorbents have high selectivity and can efficiently remove target nuclide ions from high-salt radioactive wastewater, which can rapidly reduce the radioactivity of waste liquids, and coexist with non-radiative ions. The effect is small, so it has the advantages of long service life and small amount of solid waste. In addition, the use of inorganic ion adsorbents can enrich a large amount of radionuclides in a small volume of adsorbent, so that the resulting solid waste is easy to be radiation protected. Compared with ion exchange resin, the radioactive waste produced by inorganic adsorption technology has good thermal stability and chemical stability, strong radiation resistance, and is not easily decomposed or biodegraded by radiation, which is convenient for later treatment and disposal, and long-term storage in underground disposal sites. In the process, it is more secure in the long run. Further, the waste liquid deep purification device based on the inorganic adsorption technology has a simple structure, has the characteristics of being effective, selective, miniaturized, modular, and mobile, and has low requirements for on-site service conditions, and is very suitable for a nuclear power plant. Special requirements for the composition of radioactive waste liquids and limited space on site.

At present, the nuclides removed by inorganic ion adsorbents are mainly directed to Cs, Sr, and Co. In addition to Sr adsorbents mainly include zeolite and hydrated metal oxides. Among them, hydrated titanium oxide, manganese oxide and composite oxides have good adsorption properties for Co, and metal titanate has good adsorption for Sr. Studies have shown that Sr/Co ions are mainly ion exchanged with hydroxyl groups on the surface of hydrated metal oxides, and are suitable for neutral or alkaline waste liquids. However, considering the actual process conditions, the pH range of the radioactive waste liquid is wide, and the effect of the current hydrated metal oxide type adsorbent is not particularly desirable.

The research group of Tsinghua University has successfully developed an Sb ₂ O ₅ adsorbent with excellent adsorption properties for Sr and Co ions, which is suitable for radioactive waste liquid in a wide pH range, as disclosed in ZL201410132237.5. However, the adsorbent obtained in the above patent is a powder and is not suitable for use in industrial apparatuses such as fixed bed reactors and adsorption columns. In addition, there are few studies on inorganic ion adsorbents for removing ^110m Ag from radioactive waste liquids. The only adsorbents for the removal of trace amounts of Ag ^{+ in} drinking water to date include: hydroxyapatite, montmorillonite, chitosan, amino-modified SiO _{2 ,} and organic polymers containing mercapto groups.

In view of the above, the radioactive waste liquid processing industry requires an inorganic ion adsorbent capable of simultaneously and efficiently removing ⁹⁰ Sr and ^{100 m} Ag and suitable for industrial applications such as fixed bed reactors, adsorption columns, and the like.

Summary of the invention

It is an object of the present invention to provide an inorganic ion adsorbent which is capable of simultaneously and efficiently removing ⁹⁰ Sr and ^{100 m} Ag and is suitable for industrial applications such as fixed bed reactors and adsorption columns.

The inventors of the present invention have unexpectedly found in a large number of experiments that the Sb ₂ O ₅ adsorbent can simultaneously remove ⁹⁰ Sr and ^{100 m} Ag efficiently, and the loosely bound solid on the surface of the particles containing Sb ₂ O ₅ is removed by washing. After the phase particles and the soluble ions in the particles, the polymer material layer is coated thereon, and an adsorbent other than Sr and Ag having ideal mechanical stability and low ion bleed rate can be obtained, thereby being suitable for radioactive waste of nuclear power plants. The actual engineering of liquid treatment.

In one aspect, the present invention provides a particulate Sb ₂ O ₅ adsorbent comprising: particles comprising Sb ₂ O ₅ ; and a layer of polymeric material coating the particles.

Preferably, the adsorbent according to the invention has a particle size of at least 0.2 mm, preferably a particle size of at least 0.5 mm. Further, the adsorbent according to the present invention has a particle size of 10 mm or less, preferably 5 mm or less.

Preferably, the adsorbent according to the invention has a crush strength of 2-100 N/particle.

Preferably, the adsorbent according to the present invention has such an ion leaching property that the turbidity of the resulting solution is 50 mg/L or less after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10.

Preferably, the adsorbent according to the present invention has such an ion leaching property that after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10, the resulting solution has an electric conductivity of 50 μs/cm or less.

Preferably, in the adsorbent according to the present invention, the polymer material layer comprises sodium alginate, chitosan, polyethylene glycol having a number average molecular weight of between 2000 and 6000, polyvinyl alcohol, sucrose or random combination.

The above adsorbent can not only adsorb ⁹⁰ Sr and ^{100 m} Ag nuclide ions quickly and selectively, but also has a certain size of particle state, is structurally stable, and can withstand long-term operation and rapid flushing of water flow, so that it can be filled and fixed. Bed reactor for practical engineering use.

In another aspect, the present invention is also directed to a method of preparing a particulate Sb ₂ O ₅ adsorbent, the method comprising:

1) providing particles containing Sb ₂ O ₅ ;

2) washing the particles of step 1) with deionized water until the Cl ^- ions of the washing liquid are not detected with the silver nitrate solution;

3) coating the washed particles with a polymer material, preferably in the presence of an acid or a base, to obtain coated particles;

4) Optionally, the coated particles of step 3) are washed with deionized water until the conductivity of the washing liquid is 50.0 μs/cm or less.

Thereby, the particulate Sb ₂ O ₅ adsorbent is obtained.

Preferably, according to an embodiment of the present invention, providing the Sb ₂ O ₅ -containing particles comprises: a) supporting SbCl ₃ on the particulate inorganic oxide and the particulate activated carbon support, and then b) treating the step a) with hydrogen peroxide The particles are oxidized and then hydrolyzed to form particles containing Sb ₂ O ₅ . Preferably, the particulate inorganic oxide and the particulate activated carbon support are granules of granules, typically having a particle size of from 0.5 to 3 mm.

In a specific embodiment of the invention, the particulate Sb ₂ O ₅ is prepared by the following steps:

1) carrier preparation and charging process: selecting particulate inorganic oxide and granular activated carbon carrier, and loading it into the reaction kettle, and then installing and sealing the reaction vessel;

2) Preparation of SbCl ₃ solution: weigh a certain amount of antimony trichloride SbCl ₃ , dissolve it in an anhydrous solvent to form a standby solution, and add the liquid to the dropping bottle;

3) adding SbCl ₃ solution: opening the reaction vessel to rotate, and simultaneously adding the SbCl ₃ solution to the reaction vessel, so that the material is adsorbed by the particulate inorganic oxide and the particulate activated carbon carrier;

4) Evaporation recovery solvent: the solvent is volatilized by vacuum distillation, and recovered by condensation, so that Sb (III) is uniformly supported on the surface of the particulate inorganic oxide and the particulate activated carbon support;

5) hydrogen peroxide oxidation process: a sufficient amount of hydrogen peroxide is added to the drop bottle, the valve is opened, hydrogen peroxide is slowly added dropwise into the reaction system, and Sb (III) oxidation is converted into Sb (V);

6) Complete hydrolysis process: a sufficient amount of pure water is added to the dropping bottle, the valve is opened, pure water droplets are added to the reaction vessel, and Sb(V) is completely hydrolyzed to form dispersed Sb ₂ O ₅ microcrystals on the surface of the carrier. ;

7) Cleaning and filtration of the particles: After the reaction, the reaction vessel is opened, and the particles therein are poured into a Buchner funnel for filtration, and then the particles containing Sb ₂ O ₅ are washed with pure water, preferably for 10 hours or longer, until The presence of Cl ⁻ ions is not detected with silver nitrate, and then the material is dried;

8) Adsorbent coating: coating the surface of the polymer material by the following step (7): laminating the polymer material having a binding effect in pure water to prepare a solution of a certain concentration; The obtained granules are added to the solution system; preferably, depending on the polymer material, an acid or alkali solution is added dropwise during the stirring; after the mixture is stirred for 1-10 h, solid-liquid phase separation is performed to obtain a particulate state. Sb ₂ O ₅ adsorbent; and

9) Washing and drying of the adsorbent: the particulate Sb ₂ O ₅ adsorbent obtained in the step (8) is washed with deionized water, preferably for 10 hours or longer, until the conductivity of the washing liquid is 50.0 μs/ The cm or lower and the turbidity is 50 mg/L or less, followed by solid-liquid phase separation, and the adsorbent is dried, preferably by using a constant temperature oven or a vacuum oven at a drying temperature of 60 to 120 °C.

Further, in the step (1), the particulate inorganic oxide and the particulate activated carbon support have a particle size of 0.5 to 3 mm and a crush strength of 2 to 80 N/particle.

Further, in the step (1), the preferred particulate inorganic oxide carrier comprises silica gel beads, alumina beads, titanium oxide beads, zirconia beads, and more preferably comprises silica gel beads. In the granular activated carbon carrier, both coconut shell carbon and coal-based carbon may be used.

Further, in the step (1), the reaction vessel is in an anhydrous dry state.

Further, in the step (2), the concentration of the solution of antimony trichloride SbCl ₃ in an anhydrous solvent is controlled in the range of 50 to 500 g / L; in the case of silica gel beads as a carrier, SbCl ₃ and silica gel beads The mass ratio is 1:2 to 2:1.

Further, in the step (2), optional anhydrous solvents include: ethanol, propanol, isopropanol and ethylene glycol.

Further, in the step (3), after the completion of the dropwise addition, the volume of the Sb-alcohol solution has just submerged the solid particles.

Further, in the step (4), the solvent is separated and recovered by a vacuum distillation method, and the heating method of the reaction vessel may be a water bath or an oil bath, and the temperature is controlled to 30-70 ° C until the solvent is completely evaporated, and the process is stopped. .

Further, in the step (5), the hydrogen peroxide concentration is 30 to 50 wt%; and the molar ratio of hydrogen peroxide to Sb (III) is 1:1 to 5:1.

Further, in the step (5), the reaction temperature is controlled to be 5 to 40 ° C; and the reaction time after stopping the dropwise addition of hydrogen peroxide is 1-5 h.

Further, in the step (5), chlorine gas is generated in the reaction, and the reactor is required to be evacuated by an air pump, and the discharged chlorine gas is absorbed into a Meng's gas cylinder containing a sodium thiosulfate solution, and the gas cylinder is discharged. The gas is dried over silica gel and discharged into the outdoor atmosphere.

Further, in the step (6), the mass ratio of the added water to the antimony trichloride SbCl ₃ is 1:1 to 5:1; the hydrolysis reaction temperature is controlled to be 20 to 80 ° C, and the reaction time is 2 to 8 h.

Further, in the step (7), the granules are dried in a constant temperature oven at 60 to 120 °C.

Further, in the step (8), the polymeric materials used for bonding are sodium alginate, chitosan, polyethylene glycol (2000-6000), polyvinyl alcohol, sucrose, etc.; 1% to 20% by weight; the mass ratio of the binder to the adsorbent is 5% to 30%.

Further, in the step (8), the acid added dropwise is hydrochloric acid, sulfuric acid, acetic acid or any combination thereof. Preferably, the concentration of the acid is from 0.01 to 1 mol/L.

Further, in the step (8), the base added dropwise is sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, aqueous ammonia or any combination thereof. Preferably, the concentration of the base is 0.01 to 1 mol / L;

Preferably, according to another embodiment of the present invention, providing the Sb ₂ O ₅ -containing particles comprises: a) mixing a powdered inorganic oxide carrier or a powdered activated carbon carrier with a solution of SbCl ₃ in an anhydrous solvent; The mixture obtained in the step a) is oxidized with hydrogen peroxide, followed by hydrolysis to obtain a powder carrying Sb ₂ O ₅ ; and c) the powder carrying Sb ₂ O ₅ is bonded into particles by a binder. Preferably, the powdered inorganic oxide support is a powder, usually having a specific surface area of 20 m ² /g or more; the powdered activated carbon support is a powder, usually having a specific surface area of 200 m ² /g or more.

In another embodiment of the invention, the particulate Sb ₂ O ₅ adsorbent is prepared by the following steps:

1) loading a certain amount of powdered inorganic oxide carrier or powdered activated carbon carrier into a reaction vessel with a stirring paddle and a condenser, and installing and sealing the reaction vessel;

2) preparing a certain concentration of antimony trichloride SbCl ₃ in an anhydrous solvent, and adding the solution to the reaction vessel, stirring, heating at 50 ° C ~ 80 ° C reflux, the reaction 1 ~ 3h;

3) while maintaining 50 ° C ~ 80 ° C, slowly add hydrogen peroxide in the reaction system, until the completion of the addition, the temperature is raised to 80 ~ 100 ° C, the reaction 2 ~ 4h;

4) adding ultrapure water to the reaction system of the step (3), adjusting the reaction temperature to 50 ° C to 80 ° C, stirring is continued for 2 to 6 hours, and then the precipitate is filtered, and the precipitate is washed with ion-free water. Until the Cl ^- ion could not be detected in the filtrate; the obtained precipitate was dried to obtain an inorganic oxide-supported Sb ₂ O ₅ adsorbent powder;

5) Select a suitable binder type and prepare a binder solution of a certain concentration. Adding the solution to the powder adsorbent obtained in the step 4), stirring it well with a mixer, and then extruding the wet material into a pellet of a certain particle size by a granulator, and then drying and forming, obtaining the desired Particles containing Sb ₂ O ₅ adsorbent.

6) Cleaning and filtration of the granules: The granules of the step 5) are poured into a Buchner funnel for filtration, and then the sorbent particles are washed with pure water, and then the granules are dried.

7) Adsorbent coating: coating the surface of the polymer material by the surface of the adsorbent obtained in the step (6) as follows: dissolving the polymer material having a binding effect in pure water to prepare a solution having a certain concentration; 6) The obtained granules are added to the solution system; preferably, depending on the polymer material, an acid or alkali solution is added dropwise during the stirring; after the mixture is stirred for 1-10 h, solid-liquid phase separation is performed to obtain granules. State Sb ₂ O ₅ adsorbent.

8) Optional sorbent cleaning: The particulate Sb ₂ O ₅ adsorbent obtained in the step (7) is washed with deionized water, preferably for 10 hours or longer, until the conductivity of the washing liquid is 50.0 μs. /cm or lower and the turbidity is 50 mg/L or less, followed by solid-liquid phase separation, and the adsorbent is dried, preferably by a constant temperature oven or a vacuum oven at a drying temperature of 60 to 120 °C.

Further, in the step (1), the reaction vessel is in an anhydrous dry state.

Further, in the step (1), the powdery inorganic oxide carrier comprises silica, alumina, titania, zirconia or a combination thereof; the powdered activated carbon carrier may be selected from coal-based carbon or coconut shell charcoal.

Further, in the step (1), a preferred inorganic oxide support is a silica support. The carrier has an amorphous amorphous structure, and may be a commercially available microsilica powder having a particle size of nanometer to submicron and a specific surface area of >800 m ² /g; or a self-prepared silicon oxide powder, and a preparation method thereof It may be an acid or base catalyzed hydrolysis using methyl silicate, ethyl silicate, sodium silicate or the like.

Further, in the step (1), a preferred inorganic oxide carrier is an alumina carrier. The carrier has a γ crystal form, which may be a commercially available pseudoboehmite, and has a specific surface area of >100 m ² /g. It may also be a self-prepared alumina powder, which can be obtained by a precipitation method using an alkaline solution and a soluble aluminum salt. γ crystal alumina. The alkaline solution in the process may be ammonia water, sodium hydroxide, sodium carbonate or an aqueous urea solution; the soluble aluminum salt may be aluminum nitrate or aluminum chloride.

Further, in the step (1), a preferred inorganic oxide carrier is a titanium oxide carrier. The carrier has an anatase crystal form, which may be a commercially available titanium oxide powder, and has a specific surface area of >50 m ² /g. It may also be a self-prepared titanium oxide powder, and an anatase crystal may be obtained by a titanium salt hydrolysis method. Type titanium oxide, the titanium salt in the process may be titanium tetrachloride or tetrabutyl titanate.

Further, in the step (1), a preferred inorganic oxide support is a zirconia support. The carrier has a monoclinic phase, and may be a commercially available low-temperature heat-treated monoclinic zirconia powder having a specific surface area of >50 m ² /g; or a self-prepared zirconia powder, which may be an alkaline solution and soluble. The zirconium salt is obtained by precipitation to obtain monoclinic phase zirconia. The alkaline solution in the process may be ammonia water, sodium hydroxide, sodium carbonate or an aqueous urea solution; the soluble zirconium salt may be zirconium oxychloride, and the temperature treatment is less than 200 °C.

Further, in the step (2), the optional anhydrous solvent comprises: ethanol, propanol, isopropanol or ethylene glycol.

Further, in the step (2), the concentration of the solution of SbCl ₃ in an anhydrous solvent is controlled in the range of 50 to 500 g/L.

Further, in the step (2), the molar ratio of the Sb (III) to the inorganic oxide carrier or the activated carbon carrier is 1:2 to 1:6.

Further, in the step (3), the hydrogen peroxide concentration is 8 to 30 wt%; and the molar ratio of hydrogen peroxide to Sb (III) is 1:1 to 5:1.

Further, in the step (4), the mass ratio of the added water to the antimony trichloride SbCl ₃ is 1:1 to 5:1.

Further, in the step (4), the powder containing Sb ₂ O ₃ is dried in a constant temperature oven at 60 to 120 °C.

Further, in the step (5), the binders selected are sodium alginate, polyethylene glycol (2000-6000), polyvinyl alcohol, sucrose, etc.; and the solution concentration is 1% to 20% by weight.

Further, in the step (5), the powder Sb ₂ O ₅ adsorbent is added to a certain volume of the binder solution, and is vigorously stirred by a stirrer to form a uniform wet material, wherein the binder and the adsorbent are controlled. The mass ratio is 5% to 30%.

Further, in the step (5), granulation is carried out by using an extrusion granulator, and the apparatus is adjusted to control the particle size in the range of 0.5 to 3 mm.

Further, in the step (5), the obtained particle sample is slowly dried by a low temperature vacuum at a temperature of 40 to 60 ° C to obtain a particle containing Sb ₂ O ₅ .

Further, in the step (6), the particles are washed with deionized water until the presence of Cl ⁻ ions is not detected by the silver nitrate solution.

Further, in the step (6), the granules are dried in a constant temperature oven at 60 to 120 °C.

Further, in the step (7), the polymer materials having binding effects are sodium alginate, chitosan, polyethylene glycol (2000-6000), polyvinyl alcohol, sucrose, etc.; 1% to 20% by weight; the mass ratio of the polymer material to the particles is 5% to 30%.

Further, in the step (7), the acid added dropwise is hydrochloric acid, sulfuric acid, acetic acid or any combination thereof. Preferably, the concentration of the acid is from 0.01 to 1 mol/L.

Further, in the step (7), the base added dropwise is sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, aqueous ammonia or any combination thereof. Preferably, the concentration of the base is from 0.01 to 1 mol/L.

The inventors of the present invention have recognized that the water washing process of the Sb ₂ O ₅ -containing particles can remove the loose partial solid phase particles on the surface of the particles and sufficiently release the soluble ions in the primary adsorbent. The washed primary adsorbent has good mechanical strength and low ion leaching characteristics. Further, by coating the surface of the washed primary adsorbent with a polymer layer, the mechanical strength of the adsorbent can be further increased, thereby obtaining an adsorbent preferably having a crush strength of 2 to 100 N/particle and an extremely low ion leaching property.

DRAWINGS

Figure 1 shows the adsorption kinetics of the adsorbents for Ag ⁺ and Sr ²⁺ ions in accordance with the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, but the invention is not limited to the following examples. The method is a conventional method unless otherwise specified, and the raw materials and standard chemical reagents used for the detection can be obtained from an open commercial route unless otherwise specified.

In the following examples, the adsorbents were subjected to static adsorption and fixed bed adsorption reaction column performance tests. The concentrations of Sr ²⁺ and Ag ⁺ ions before and after adsorption were determined by plasma mass spectrometry (ICP-MS). It is represented by the distribution coefficient K _d and the decontamination coefficient DF.

Determination of static adsorption, the adsorbent is added to an amount of 50mL centrifuge tube, placed in a thermostatic shaker shaken 48h ~ 72h, measured before and after the adsorption of Sr ²⁺ and Ag ⁺ ion concentration, adsorbent performance using the distribution coefficient K _d, and The decontamination coefficient DF is expressed. The adsorption partition coefficient K _d (mL/g) is shown in the following formula 1, where C ₀ and C _t are the initial concentration of the adsorbed ions and the concentration after reaching the adsorption equilibrium, respectively, F is the volume of the treated solution (mL) and the mass of the adsorbent. Ratio of (mg). The decontamination coefficient is as shown in the following formula 2, which is the ratio of the influent concentration of the adsorbed ions to the effluent concentration after reaching the adsorption equilibrium. The general adsorption partition coefficient indicates the characteristics of the adsorbent material itself. The K _d value above 10 ⁵ indicates that the performance of the adsorbent is good; the size of the decontamination coefficient is not only related to the adsorption characteristics of the material itself, but also related to the amount of the adsorbent. A larger value indicates a cleaner removal of contaminants.

Kd=(Co–Ct)×F×1000/Ct (1)

The dynamic adsorption performance was carried out 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 crushing strength of the adsorbent according to the present invention is determined by the following: the crushing strength of the adsorbent is measured by a domestic crushing strength meter, and the instrument model is a YHKC-2A type particle strength measuring instrument. In the measurement, 60-100 adsorbent particles are randomly selected. When measuring, the particles are placed at the center of the hammer directly below, and the handle is rotated to make the hammer fall. When approaching the particles, slowly rotate, so that the hammer is slowly contacted. When the sound of particle breakage is heard, the instrument gives the number of Newtons of force applied to the particles at the moment of crushing.

The ion leaching characteristics of the adsorbent according to the present invention are determined by first immersing the adsorbent in 10 volumes of pure water, stirring with a stirrer, or shaking with a shaker, and after a certain time, respectively using HACH The 2100 N-type turbidity meter and the DDSJ-308A conductivity meter were used to determine the turbidity and conductivity of the immersion liquid. The accuracy of the turbidimeter is 0.001 mg/L, and the accuracy of the conductivity meter is 0.01 μs/cm.

Example 1: Preparation of granulated Sb ₂ O ₅ adsorbent

1) The selected silica gel particles were sieved in advance, and a carrier having a particle diameter of 1 mm was used as a test carrier, and the crushing strength was determined to be 3 to 4 N/particle. 500 g of silica gel particles were weighed, charged into a reaction kettle, and the reactor was installed.

2) Weigh 663.6g of antimony trichloride SbCl ₃ and dissolve it in 2L of absolute ethanol to form a standby solution; open the vacuum pump of the reaction kettle, and use the vacuum to suck the material Sb-ethanol solution into the material bottle I, to be fully inhaled. After that, the vacuum pump is turned off to separate the material bottle from the vacuum system.

3) Open the reactor rotation controller, adjust the rotation speed to 20 rpm, and slowly add the material Sb-ethanol solution into the reaction kettle. The material is uniformly adsorbed by the silica gel and keep the liquid level exceeding the solid material. After all the solutions were added dropwise, the reaction vessel was further rotated for 1 h to uniformly impregnate the solution on the silica gel.

4) Turn on the chiller to allow the cooling water to enter the condenser and bring the condensing temperature below 5 °C. Ionized water was added to the water bath of the reaction kettle, and electric heating was started, and the temperature was set to 60 °C. Turn on the vacuum pump for vacuum distillation until all the ethanol has evaporated.

5) 400 mL of hydrogen peroxide (30 wt%) was vacuumed into the vial II, and the hydrogen peroxide was slowly added dropwise into the reaction vessel during the reaction and uniformly adsorbed by the solid. In the process, a small air pump is used to inject a negative pressure into the reaction system, and the generated chlorine gas is taken out and absorbed by the sodium thiosulfate solution in the gas washing bottle. After the addition of the hydrogen peroxide droplets, the reaction was carried out for 2 h at a water bath temperature of 5 ° C and maintaining aeration.

6) Turn on the electric heating and adjust the water bath temperature to 30 °C. 2 L of pure water was added to the material bottle II, and pure water was added to the reaction vessel in the reaction, and reacted at a water bath temperature of 30 ° C for 5 hours to completely hydrolyze Sb (V).

7) After the reaction, the reaction vessel was opened, and the contents were poured into a Buchner funnel for filtration, followed by washing with pure water until no Cl ⁻ ions were detected with the silver nitrate solution. Finally, the adsorbent was dried at 100 °C.

8) Using sodium alginate as a binder, sodium alginate is first dissolved in pure water to prepare a solution having a concentration of 1 to 10% by weight. Add the adsorbent obtained in step 7) to the solution system, the liquid-solid ratio is 10:1; after stirring for 1 hour, add 1M hydrochloric acid solution until the pH value is 4-5, continue stirring and react for 2-10h, solid-liquid Phase separation.

9) The particle adsorbent obtained in the step 8) is further washed with ion-free water, and the volume of water used for each cleaning is 10 times the volume of the adsorbent until the conductivity of the cleaning solution is less than 20 μs/cm, followed by solid-liquid phase separation. And the adsorbent was vacuum dried to obtain a particulate Sb ₂ O ₅ adsorbent.

The crushing strength of the prepared adsorbent was determined to be 3-15 N/particle, and after immersion for 24 h under the liquid-solid ratio of 10, the turbidity in the liquid was 20-30 mg/L, and the conductivity was 16.3 μs/ Cm, the COD concentration in the solution is <1.0 mg/L. The adsorption and removal properties of Ag and Sr ions of the obtained adsorbents were tested by static adsorption method. Under the initial ion concentration of 10 mg/L, the adsorption partition coefficient K _d of Ag ions was 3.8×10 ⁴ mL/g. adsorption capacity of 32mg / g; adsorption ratio of Sr ions K _d of 5.5 × 10 ⁴ mL / g, the adsorption capacity of 35mg / g.

Example 2: Preparation of granular Sb ₂ O ₅ adsorbent

1) 500 g of microsilica powder carrier is loaded into a reaction vessel with a stirring paddle and a condenser, and the reactor is installed and sealed;

2) Weigh 663.6g of antimony trichloride SbCl ₃ , dissolve it in 2L of absolute ethanol to form a backup solution, add the solution to the reaction kettle, start stirring, and heat to reflux at 50 ° C ~ 80 ° C, the reaction 1~3h;

3) while maintaining 50 ° C ~ 80 ° C, slowly add 500 mL of hydrogen peroxide in the reaction system, until the completion of the addition, the temperature is raised to 80 ~ 100 ° C, the reaction 2 ~ 4h;

4) adding ultrapure water to the reaction system of the step (3), adjusting the reaction temperature to 50 ° C to 80 ° C, stirring is continued for 2 to 6 hours, and then the precipitate is filtered, and the precipitate is washed with ion-free water. Until the Cl ^- ion is not detected in the filtrate; the obtained precipitate is dried to obtain a Sb ₂ O ₅ /SiO ₂ adsorbent powder deposited with Sb ₂ O ₅ microcrystals;

5) Select polyvinyl alcohol and sucrose as a binder, and prepare it into a solution, wherein the polyvinyl alcohol has a concentration of 1 to 10% by weight and a sucrose concentration of 10 to 30% by weight. The mixed solution is added to the powder adsorbent obtained in the step 4), and uniformly stirred by a stirrer, and the wet material is extruded by a granulator to form a pellet having a particle size of 1 to 3 mm, and the pellet is collected at 60 ° C. Dry under vacuum.

6) Polyvinyl alcohol (2000) is used as a coating material, and polyvinyl alcohol is dissolved in pure water to prepare a solution having a concentration of 1 to 5 wt%. The adsorbent obtained in the step 5) is added to the solution system, and the liquid-solid ratio is 10:1; the stirring is continued and the reaction is carried out for 2-10 hours, and then the solid phase is separated.

7) The particle adsorbent obtained in the step 5) is further washed with ion-free water, and the volume of water used for each washing is 10 times the volume of the adsorbent until the conductivity of the cleaning solution is less than 50 μs/cm, followed by solid-liquid phase separation. And the adsorbent was vacuum dried to obtain the final particulate Sb ₂ O ₅ adsorbent.

The average crushing strength of the particulate Sb ₂ O ₅ adsorbent was measured and found to be 3 to 20 N/particle. After soaking for 24 hours under the condition of liquid-solid ratio of 10, the turbidity in the liquid is <10.0 mg/L, the conductivity is 10-20 μs/cm, and the COD concentration in the solution is <1.0 mg/L. The adsorption kinetics curves of the adsorbents for Ag ⁺ and Sr ²⁺ ions were determined, as shown in Figure 1. During the adsorption test, the initial concentration of ions was 10 mg/L, the volume of the solution was 1 L, and the adsorbent was 500 mg. The ion equilibrium concentration of the adsorbent at different times was determined. It can be seen from the kinetic curve that the adsorption rate of Ag ⁺ and Sr ²⁺ ions by Sb ₂ O ₅ adsorbent is very fast, Ag ⁺ ion can reach equilibrium adsorption in 3 min, and Sr ²⁺ ion reaches within 1 to 3 min. More than 90% of the equilibrium adsorption.

As can be seen from the above results, the particulate Sb ₂ O ₅ adsorbent of the present invention can simultaneously effectively remove both Sr ions and Ag ions. Moreover, since Sb ₂ O _{5 of the} present invention has a certain degree of granularity and mechanical stability, it can withstand long-term operation and rapid flushing of water flow, and can be loaded into a fixed bed reactor for practical engineering use.

Example 3: Preparation of granular Sb ₂ O ₅ / activated carbon adsorbent

1) 2 L of absolute ethanol was added to the reaction vessel, and 663.6 g of antimony trichloride SbCl _{3 was} weighed and stirred to completely dissolve.

2) Add 2000g of activated carbon powder to the reaction kettle, mix well, control the temperature of the reaction kettle to 30-40 ° C, and react at a constant temperature for 3-5 h to uniformly adsorb the Sb material on the surface of the activated carbon.

3) Turn on the chiller to allow the cooling water to enter the condenser and bring the condensing temperature below 5 °C. The temperature of the reactor was raised to 80 ° C, and the solvent ethanol was distilled off until all the ethanol was evaporated.

4) 250 mL of hydrogen peroxide (30 wt%) was vacuumed into the material bottle I, and the temperature of the reaction kettle was controlled to 5 ° C with a cold water bath, and hydrogen peroxide was slowly added dropwise into the reaction vessel and uniformly adsorbed by the solid. In the process, a small air pump is used to inject a negative pressure into the reaction system, and the generated chlorine gas is taken out and absorbed by the sodium thiosulfate solution in the gas washing bottle. After the addition of the hydrogen peroxide droplets, the reaction was carried out for 2 to 5 hours at 5 ° C and under aeration.

5) Turn on the electric heating and adjust the water bath temperature to 30 °C. 2 L of pure water was added to the material bottle II, and pure water was added to the reaction vessel in the reaction, and reacted at a water bath temperature of 30 ° C for 5 hours to completely hydrolyze Sb (V).

6) After the reaction, the reaction vessel was opened, and the contents were poured into a Buchner funnel for filtration, followed by washing with pure water until no Cl ⁻ ions were detected with the silver nitrate solution. Finally, the adsorbent was dried at 100 °C.

7) Select polyethylene glycol (6000) and sucrose as a binder, and prepare it into a mixed solution, wherein the polyvinyl alcohol concentration is 10 to 30 wt%, the sucrose concentration is 5 to 20 wt%, and the polyethylene glycol and sucrose The mass ratio is 1:1 to 3:1. The mixed solution is added to the powder adsorbent obtained in the step 6), and uniformly stirred by a stirrer, and the wet material is extruded by a granulator to form a pellet having a particle size of 0.5 to 3 mm, and the pellet is collected at 60 ° C. Drying under vacuum gave the desired particulate Sb ₂ O ₅ /activated carbon adsorbent.

8) Using sodium alginate as a coating agent, sodium alginate is first dissolved in pure water to prepare a solution having a concentration of 1 to 10% by weight. Add the adsorbent obtained in step 7) to the solution system, the liquid-solid ratio is 10:1; after stirring for 1 hour, add 1M hydrochloric acid solution until the pH value is 4-5, continue stirring and react for 2-10h, solid-liquid The phases were separated and the solid obtained was dried at 60 °C.

9) The particle adsorbent obtained in the step 8) is further washed with ion-free water, and the volume of water used for each cleaning is 10 times the volume of the adsorbent until the conductivity of the cleaning solution is less than 20 μs/cm, followed by solid-liquid phase separation. And the adsorbent was vacuum dried to obtain a particulate Sb ₂ O ₅ /activated carbon adsorbent.

It was determined that the crushing strength of the prepared adsorbent was 5-20 N/particle, and the turbidity in the liquid was <20 mg/L and the conductivity was <20 μs/cm after soaking for 24 hours under the condition of liquid-solid ratio of 10. The COD concentration in the solution was <1.5 mg/L. The adsorption and removal properties of Ag and Sr ions of the obtained adsorbents were tested by static adsorption method. Under the initial ion concentration of 10 mg/L, the adsorption partition coefficient K _d of Ag ions was 7.4×10 ⁴ mL/g. adsorption capacity of 47mg / g; adsorption ratio of Sr ions K _d of 9.3 × 10 ⁴ mL / g, the adsorption capacity of 41mg / g.

The various aspects of the present invention have been explained above by way of specific embodiments, but those skilled in the art can understand that the present invention is not limited to the specific embodiments described above, and various specific techniques disclosed herein will be apparent to those skilled in the art. Equivalent substitutions of means, materials, process steps, and the like, as well as combinations of various technical means, materials, process steps, and the like, are within the scope of the invention.

To further illustrate certain aspects of the invention, the invention also specifically provides some non-limiting embodiments as follows:

A particulate Sb ₂ O ₅ adsorbent for removing radioactive ⁹⁰ Sr and ^{110 m} Ag, comprising: particles containing Sb ₂ O ₅ ; and a layer of a polymer material covering the particles.

2. The particulate Sb ₂ O ₅ adsorbent of embodiment 1 having a particle size of at least 0.2 mm.

3. The particulate Sb ₂ O ₅ adsorbent according to embodiment 2, which has a particle size of from 0.5 to 5 mm.

4. The particulate Sb ₂ O ₅ adsorbent according to embodiment 1 or 2, which has a crush strength of 2-100 N/particle.

5. The particulate Sb ₂ O ₅ adsorbent according to embodiment 1 or 2, which has such ion leaching characteristics that the turbidity of the resulting liquid is obtained after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10. The degree is 50 mg/L or less.

6. The particulate Sb ₂ O ₅ adsorbent according to embodiment 1 or 2, which has such ion leaching characteristics that the conductance of the resulting liquid is obtained after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10. The rate is 50 μs/cm or less.

7. The particulate Sb ₂ O ₅ adsorbent according to embodiment 1 or 2, wherein the polymer material layer comprises sodium alginate, chitosan, and poly(B) having a number average molecular weight of between 2000 and 6000. Glycol, polyvinyl alcohol, sucrose or any combination thereof.

8. A method for preparing a particulate Sb ₂ O ₅ adsorbent for removing radioactive ⁹⁰ Sr and ^{110 m} Ag, the method comprising:

1) providing particles containing Sb ₂ O ₅ ;

3) coating the washed particles with a polymer material to obtain coated particles;

4) Optionally, the coated particles of step 3) are washed with deionized water until the conductivity of the washing liquid is 50.0 μs/cm or less and the turbidity is 50 mg/L or less.

Thereby, the particulate Sb ₂ O ₅ adsorbent is obtained.

9. The method of embodiment 8 wherein the step of providing particles comprising Sb ₂ O ₅ comprises,

a) supporting SbCl ₃ on the particulate inorganic oxide and the particulate activated carbon support, and then

b) oxidizing the particles obtained in the step a) with hydrogen peroxide, followed by hydrolysis to form particles containing Sb ₂ O ₅ .

10. The method of embodiment 8 wherein the step of providing particles comprising Sb ₂ O ₅ comprises,

a) mixing a powdered inorganic oxide carrier or a powdered activated carbon carrier with a solution of SbCl ₃ in an anhydrous solvent;

b) oxidizing the mixture obtained in the step a) with hydrogen peroxide, followed by hydrolysis to obtain a powder carrying Sb ₂ O ₅ ;

c) The powder carrying Sb ₂ O ₅ is bonded into particles with a binder.

11. The method according to embodiment 9 or 10, wherein the polymer material comprises sodium alginate, chitosan, polyethylene glycol having a number average molecular weight of between 2000 and 6000, polyvinyl alcohol, and sucrose. Or any combination thereof.

12. The method of embodiment 9 or 10, wherein the step of coating the washed particles with a polymeric material is carried out in the presence of an acid or a base.

The method according to embodiment 12, wherein the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, acetic acid or a combination thereof, preferably having a concentration of 0.01 to 1 mol/L.

The method according to embodiment 12, wherein the base is selected from the group consisting of sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, aqueous ammonia or a combination thereof, preferably having a concentration of from 0.01 to 1 mol/L.

15. The method of embodiment 9, wherein the particulate inorganic oxide support comprises silica gel beads, alumina beads, titanium oxide beads, zirconia beads, molecular sieve beads, or a combination thereof, preferably having Particle size of 0.3 to 5 mm, and/or crush strength of 2-150 N/particle. The particulate activated carbon support may be coal-based carbon or coconut shell charcoal, preferably having a particle size of 0.3 to 5 mm, and/or a crush strength of 2-150 N/particle.

16. The method of embodiment 10, wherein the powdered inorganic oxide support comprises silica powder, alumina powder, titanium oxide powder, zirconia powder, molecular sieve powder, or a combination thereof. Powdered activated carbon powder can be selected from coal-based carbon or coconut shell charcoal.

The method of embodiment 10, wherein the powdered inorganic oxide support comprises a submicron silica powder, preferably having a specific surface area greater than 800 m ² /g. The powdered activated carbon support may be coal-based carbon or coconut shell char, and has a specific surface area of more than 800 m ² /g.

18. A particulate Sb ₂ O ₅ adsorbent prepared by the process of any of embodiments 8-17.

19. Use of the particulate Sb ₂ O ₅ adsorbent according to any one of embodiments 1-7 or embodiment 18 for the removal of radioactive ⁹⁰ Sr.

20. Use of the particulate Sb ₂ O ₅ adsorbent according to any one of embodiments 1-7 or embodiment 18 for removing radioactive ^{100 m} Ag.

21. Use of the particulate Sb ₂ O ₅ adsorbent according to any one of embodiments 1-7 or by embodiment 18 for the removal of radioactive ⁹⁰ Sr and ^{100 m} Ag.

22. A method of removing radioactive ⁹⁰ Sr, the method comprising using the particulate Sb ₂ O ₅ adsorbent of any of embodiments 1-7 or by embodiment 18.

23. A method of removing radioactive ^100m Ag, the method comprises using any one of the embodiments 1-7 or the embodiment of the particulate 18 Sb ₂ O ₅ adsorbent.

24. A method of removing radioactive ⁹⁰ Sr and ^{100 m} Ag, the method comprising using the particulate Sb ₂ O ₅ adsorbent of any of embodiments 1-7 or by embodiment 18.

Claims

A particulate Sb 2 O 5 adsorbent for removing radioactive 90 Sr and 110 m Ag, comprising: particles containing Sb 2 O 5 ; and a layer of a polymer material covering the particles.
The particulate Sb 2 O 5 adsorbent of claim 1 having a particle size of at least 0.2 mm.
The particulate Sb 2 O 5 adsorbent according to claim 1 or 2, which has a crush strength of 2 to 100 N/particle.
The particulate Sb 2 O 5 adsorbent according to claim 1 or 2, which has such an ion leaching property that after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10, the turbidity of the obtained liquid is 50mg/L or lower.
The particulate Sb 2 O 5 adsorbent according to claim 1 or 2, which has such an ion leaching property that the conductivity of the resulting liquid is obtained after the adsorbent is immersed for 24 hours at a liquid-solid ratio of 10. 50 μs/cm or less.
The particulate Sb 2 O 5 adsorbent according to claim 1 or 2, wherein the polymer material layer comprises sodium alginate, chitosan, and polyethylene glycol having a number average molecular weight of between 2,000 and 6,000. , polyvinyl alcohol, sucrose or any combination thereof.
A method for preparing a particulate Sb 2 O 5 adsorbent for removing radioactive 90 Sr and 110 m Ag, the method comprising:

1) providing particles containing Sb 2 O 5 ;

2) washing the particles of step 1) with deionized water until the Cl - ions of the washing liquid are not detected with the silver nitrate solution;

3) coating the washed particles with a polymer material, preferably in the presence of an acid or a base, to obtain coated particles;

4) Optionally, the coated particles of step 3) are washed with deionized water until the conductivity of the washing liquid is 50.0 μs/cm or less and the turbidity is 50 mg/L or less.

Thereby, the particulate Sb 2 O 5 adsorbent is obtained.
The method according to claim 7, wherein the step of providing particles containing Sb 2 O 5 comprises

a) supporting SbCl 3 on the particulate inorganic oxide and the particulate activated carbon support, and then

b) oxidizing the particles obtained in the step a) with hydrogen peroxide, followed by hydrolysis to form particles containing Sb 2 O 5 .
The method according to claim 7, wherein the step of providing particles containing Sb 2 O 5 comprises

a) mixing a powdered inorganic oxide or powdered activated carbon support with a solution of SbCl 3 in an anhydrous solvent;

b) oxidizing the mixture obtained in the step a) with hydrogen peroxide, followed by hydrolysis to obtain a powder carrying Sb 2 O 5 ;

c) The powder carrying Sb 2 O 5 is bonded into particles with a binder.
A particulate Sb 2 O 5 adsorbent prepared by the method of any one of claims 7-9.
Use of the particulate Sb 2 O 5 adsorbent according to any one of claims 1 to 6 or claim 10 for removing radioactive 90 Sr and 110 m Ag.