Inorganic ion exchange resin as well as preparation method and application thereof

Abstract

The invention provides a preparation method of inorganic ion exchange resin, and belongs to the technical field of treatment of low-radioactivity waste liquid by an electrodeionization technology. The preparation method comprises the following steps: uniformly mixing an inorganic ion exchange powder material, an inorganic binder and a pore-foaming agent, and granulating; then drying for 0.5 to 3h at the temperature of 60 to 120 DEG C; and finally, calcining at 350-600 DEG C for 0.5-4 hours to obtain the inorganic ion exchange resin. And the inorganic ion exchange powder material is alpha-Zr (HPO4) 2 or ZrO2. When the inorganic ion exchange resin prepared by the invention is applied to a CEDI process in a constant voltage mode, the desalination rate is equivalent to that of organic ion exchange resin, and the desalination energy consumption of the process based on alpha-Zr (HPO4) 2 and ZrO2 inorganic ion exchange resin is lowest. As the inorganic ion exchange material is good in radiation resistance, an electrodeionization system based on the resin is expected to have longer service time.

Description

Technical Field

[0001] The present invention relates to the technical field of treating low-level radioactive waste liquid using electrodeionization technology, and in particular to an inorganic ion exchange resin and a preparation method and application thereof. Background Art

[0002] Due to the non-renewable nature of fossil fuels and the limitations of renewable energy, nuclear energy is gaining increasing attention as a vital energy source. The development of new nuclear power plants worldwide has generated significant amounts of radioactive wastewater. Since the direct discharge of large amounts of radioactive wastewater from the nuclear industry poses significant risks to humans and the ecological environment, timely reduction and advanced purification are essential. Numerous integrated chemical, physical, and biological treatment methods have been developed for the purification of radioactive wastewater, including chemical precipitation, ion exchange, evaporation and concentration, and biological treatment. While chemical precipitation is simple and economical for treating radioactive wastewater, its application is limited by the difficulties of solid-liquid separation, the large amount of sludge produced, and the presence of secondary contamination. While ion exchange offers a high removal rate for radionuclide ions, it is less effective for treating low-valence radionuclide ions. Furthermore, once the ion exchange resin reaches saturation, it is directly stored as radioactive organic waste. Currently, significant amounts of this organic waste are directly stored at nuclear power plants worldwide. While evaporation and concentration offer high purification coefficients, they consume significant amounts of heat energy, have low heat efficiency, and are expensive. Biological treatment not only requires large oxidation ponds but also suffers from time-consuming processes, incomplete radioactive removal, and low efficiency. These conventional methods all have drawbacks when it comes to treating low-level radioactive waste, necessitating the search for a clean, efficient treatment method.

[0003] As electrodialysis technology matured, researchers began exploring ways to combine it with other separation methods to improve separation effectiveness and process efficiency. The combination of ion exchange and electrodialysis garnered significant attention, ultimately leading to the development of an innovative water treatment process: (Continuous) Electrodeionization (CEDI or EDI).

[0004] The CEDI process achieves efficient and deep ion separation by filling the desalination chamber formed between an anion exchange membrane and a cation exchange membrane with anion exchange resin and / or cation exchange resin. The conductive properties of ion exchange resin significantly enhance the conductivity of ions in an electric field, effectively improving ion migration rate and impurity removal efficiency. During operation, the electric field not only promotes the migration of ions from the water but also continuously regenerates the ion exchange resin, eliminating the frequent regeneration chemical consumption required in traditional ion exchange processes. This technology combines the advantages of electrodialysis and ion exchange, improving water purification while reducing the use of chemical reagents and wastewater discharge, making it more environmentally friendly.

[0005] Furthermore, the high efficiency of CEDI technology has led to its widespread application in high-purity water production, the electronics industry, the pharmaceutical industry, the radioactive wastewater industry, and laboratory water. Compared to traditional water treatment methods, CEDI not only operates continuously and does not require acid-base regeneration resins, but also offers advantages in low energy consumption and operating costs, demonstrating significant application potential and sustainable development prospects.

[0006] Currently, CEDI is basically based on organic ion exchange resins when treating saline wastewater, including low-level liquid waste. Researchers widely believe that CEDI is a technology with great development potential, especially in removing trace radionuclides and reducing radioactive waste. It shows important application prospects. Yeon et al. studied the application of continuous electrodeionization (CEDI) technology in removing Co from primary coolant in nuclear power plants. 2+ The experiment used ion exchange resin and ion exchange fiber as filling materials. The results showed that ion exchange fiber has faster exchange kinetics and higher Co 2+ The removal rate makes it superior to traditional ion exchange resins. In another study, different types of organic ion exchange resins were filled, including strongly acidic cation exchange resin (Amberlite IRN77) and strongly basic anion exchange resin (Amberlite IRN78); and improvements were made to the bed structure of the resin stacking, with cation exchange resin filled in the bottom layer, mainly for removing metal cations, anion exchange resin filled in the middle layer, mainly for removing anions, and a mixed layer of anion and cation exchange resins filled in the top layer, for adjusting the pH of the solution. This bed structure effectively avoids side reactions between metal ions and hydroxide ions, while achieving an ion removal rate of over 99% and a current efficiency of 30%, demonstrating significant separation effects and energy efficiency advantages.

[0007] There are reports in the literature (Dzyazko, Yu.S., Ponomaryova, LN, Rozhdestvenskaya, LM, et al. Electrodeionization of low-concentrated multicomponent Ni 2+ -containing solutions using organic–inorganic ion-exchanger[J].Desalination 2014,342:43-51.) Inorganic zirconium hydrogen phosphate nanoparticles or nanoparticle aggregates are generated in situ in an organic cation exchange resin to form an organic-inorganic hybrid cation exchange resin. Subsequently, the hybrid resin is loaded into a CEDI system to remove Ni-containing 2+ ,Ca 2+ ,Mg2+ The results show that organic-inorganic hybrid cation exchange resin can effectively remove Ni 2+ Furthermore, inorganic hybrid resins are more resistant to contamination from organic impurities in wastewater than organic resins. While organic-inorganic hybrid resins exhibit excellent mechanical strength, the zirconium hydrogen phosphate content should not exceed 40% by weight. Exceeding this value reduces the mechanical strength of the hybrid resin. When added to a CEDI system, it easily pulverizes and is lost with water, impacting desalination performance and quality. Therefore, hybrid resins containing zirconium hydrogen phosphate content exceeding 40% are not suitable for use in CEDI systems.

[0008] Regarding the application of CEDI technology in the treatment of low-level waste, researchers have focused more on filling conventional organic ion exchange resins and exploring process parameters. Zhang et al. studied the effects of current, feed flow rate, feed concentration, and volume reduction factor on the Cs + The CEDI process was further optimized based on the removal effect. Organic ion exchange resins have high ion exchange capacity and strong resin conductivity. When used in CEDI to treat low-level radioactive liquid waste, they have the advantages of fast processing speed and high removal rate. However, organic ion exchange resins have poor radiation resistance, and the treatment of the organic resin radioactive waste produced in this process is quite cumbersome, further increasing the cost of operation and subsequent treatment of radioactive solid waste. Therefore, in order to address the problem of poor radiation resistance of organic ion exchange resins, there is an urgent need to find an inorganic ion exchange resin with good radiation resistance, high ion exchange capacity, and strong conductivity for the treatment of low-level radioactive liquid waste. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides an inorganic ion exchange resin. In a CEDI or EDI process under a constant voltage mode, the inorganic ion exchange resin has a desalination rate comparable to that of an organic ion exchange resin, while consuming less energy for desalination.

[0010] The technical solutions of the present invention are as follows:

[0011] The present invention provides a method for preparing an inorganic ion exchange resin, comprising the following steps:

[0012] (1) Granulation: Mix the inorganic ion exchange powder material, inorganic binder and porogen and then granulate;

[0013] (2) Dehydration and curing: After step (1), drying at 60-120°C for 0.5-3h;

[0014] (3) Calcination: After step (2), calcining at 350-600° C. for 0.5-4 h to obtain an inorganic ion exchange resin;

[0015] The inorganic ion exchange powder material is α-Zr(HPO4)2 or ZrO2.

[0016] During calcination in step (3), the calcination temperature has a significant impact on the performance of the ion exchange powder material after granulation. If the temperature is too low, the binder and porogen cannot be fully solidified with the powder, the particles have low mechanical strength, and are easily pulverized when exposed to water; a lower calcination temperature can reduce the dehydration condensation of hydroxyl groups in zirconium hydrogen phosphate, retain ion exchange sites, and thus the sintered material has a higher ion exchange capacity. If the temperature is too high, the particles agglomerate to reduce the specific surface area, the exchange sites are wrapped, and at the same time, the high temperature induces crystal phase transformation, lattice distortion, and hydroxyl dehydration condensation, blocking the ion transmission channel, resulting in a significant decrease in ion exchange capacity. An appropriate calcination temperature can achieve a synergistic improvement in the ion exchange capacity and mechanical strength of the inorganic ion exchange resin.

[0017] In a specific embodiment of the present invention, the amount of inorganic binder used is 2 to 15% of the mass of the inorganic ion exchange powder material; the amount of porogen used is 1 to 30% of the mass of the inorganic binder; and the amount of water added during granulation is 2 to 15% of the total mass of the inorganic ion exchange powder material, inorganic binder and porogen.

[0018] Preferably, the amount of inorganic binder is 2-10% of the mass of the inorganic ion exchange powder material; the amount of porogen is 15-30% of the mass of the inorganic binder; and the amount of water added during granulation is 2-8% of the total mass of the inorganic ion exchange powder material, inorganic binder and porogen.

[0019] The addition of inorganic binders and porogens is primarily to granulate the ion exchange powder material, improve its mechanical strength, and prevent the powder from being lost with water when filled into the CEDI system. The addition of porogens can increase the porosity of the inorganic ion exchange resin, increase the ion exchange rate, and facilitate the removal of ions in the CEDI system.

[0020] In a specific embodiment of the present invention, the inorganic binder includes at least one of 8-20 wt% AlCl3 sol, 10-25 wt% SiO2 sol, phosphate, bentonite and montmorillonite; preferably, the phosphate is aluminum dihydrogen phosphate;

[0021] The porogen is a water-soluble inorganic salt; preferably, the water-soluble inorganic salt includes at least one of NaCl, KCl, MgSO4, and Na2SO4.

[0022] When granulating zirconium hydrogen phosphate powder, the selection of an inorganic binder should prioritize its bonding properties with the powder, high-temperature resistance, chemical stability, and impact on particle performance. The selection of a porogen should consider its pore-forming capacity, compatibility with the system, removal methods, environmental friendliness, and cost. Carbonates are not suitable porogens in this invention because the CO2 generated by their high-temperature calcination can negatively impact the mechanical strength of the resulting inorganic ion exchange resin.

[0023] In a specific embodiment of the present invention, the average particle size of the granulation in step (1) is 0.3 to 4 mm.

[0024] In a specific embodiment of the present invention, step (3) is calcined at 400-550° C. for 0.5-3 h.

[0025] The inorganic ion exchange resin obtained after calcination needs to have a particle diameter between 0.3 and 2.0 mm. Because the resin needs to be filled into the desalination chamber of the membrane stack, a resin diameter much smaller than the chamber thickness will have a significant impact on the membrane. If the resin diameter is larger than the chamber thickness, the particles will squeeze the membrane, causing deformation or even puncture, affecting the linear flow rate of the solution in the chamber and even causing the CEDI system to fail.

[0026] The present invention also provides an inorganic ion exchange resin prepared by the above preparation method.

[0027] In a specific embodiment of the present invention, when the inorganic ion exchange powder material is α-Zr(HPO4)2, the hydrogen ion exchange capacity of the prepared inorganic ion exchange resin is 0.66±0.04mmol / g; when the inorganic ion exchange powder material is ZrO2, the nitrate ion exchange capacity of the prepared inorganic anion exchange resin is 0.077±0.005mmol / g.

[0028] The present invention also provides the use of the inorganic ion exchange resin in continuous electrodeionization treatment of low-level waste liquid or electrodeionization treatment of low-level waste liquid.

[0029] In one embodiment, continuous electrodeionization treatment of low-level waste liquid or electrodeionization treatment of low-level waste liquid is carried out in a constant voltage mode; preferably, the constant voltage is a single pair of desalination-concentration compartment voltage difference of 1 to 5V.

[0030] In a specific embodiment, when low-level waste liquid is treated by continuous electrodeionization or when low-level waste liquid is treated by electrodeionization, the initial volume ratio of the desalinated liquid to the concentrated liquid is 1 to 9:1; preferably, when low-level waste liquid is treated by continuous electrodeionization or when low-level waste liquid is treated by electrodeionization, the initial volume ratio of the desalinated liquid to the concentrated liquid is 1:1.

[0031] In the present invention, the initial volume ratio of the desalinated liquid to the concentrated liquid is not limited to 1:1.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] In a CEDI process operating under constant voltage mode, the desalination rate using the α-Zr(HPO4)2 and ZrO2 inorganic ion exchange resins of the present invention is comparable to that of organic ion exchange resins, and the process based on the α-Zr(HPO4)2 and ZrO2 inorganic ion exchange resins of the present invention has the lowest desalination energy consumption. Due to the excellent radiation resistance of the inorganic ion exchange material, CEDI systems based on these resin particles are expected to have a longer service life, thereby generating less radioactive solid waste. Furthermore, after the service life, the inorganic ion exchange material has excellent compatibility with curing materials such as glass and cement, making its curing process safer and more efficient. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0035] In the application examples of the present invention, except for the case where the initial volume ratio of the desalted liquid to the concentrated liquid is 9:1, which will be specially explained, changes in other process parameters are all performed under the condition that the initial volume ratio of the desalted liquid to the concentrated liquid is 1:1.

[0036] Example 1

[0037] Chemical stability test of α-Zr(HPO4)2 and ZrO2 powder materials

[0038] The stability of the powder materials in pure water and acidic solutions (sulfuric acid solutions of varying concentrations) was investigated. 5g of each powder material was dispersed in 50mL of the solution and then incubated at 40°C for 7 days. The α-Zr(HPO4)2 cation exchange material dispersed well in pure water, while ZrO2 formed a milky white suspension in water. Both powder materials settled to the bottom of the solution in 49wt% and 98wt% sulfuric acid solutions. Both powder materials exhibited excellent stability in both pure water and sulfuric acid solutions.

[0039] Example 2

[0040] This embodiment provides a method for preparing zirconium oxide ZrO2 ion exchange resin:

[0041] 100g of zirconium oxide ion exchange powder, 10g of a 20% AlCl₃ solution, and 0.6g of the porogen sodium sulfate were mixed and granulated using a rotary drum to form spheres with a particle size of 2-4mm. The mixture was then dried at 105°C for 3h and calcined at 550°C for 1.5h to obtain zirconium oxide ion exchange resin with a particle size of 0.3-1.6mm.

[0042] Example 3

[0043] This embodiment provides a method for preparing zirconium oxide ZrO2 ion exchange resin. The difference from Example 2 is that the drying temperature is changed. The drying temperature of this embodiment is 120°C, and the rest is the same as Example 2.

[0044] Example 4

[0045] This embodiment provides a method for preparing zirconium oxide ZrO2 ion exchange resin. The difference from Example 2 is that the calcination temperature is changed. The calcination temperature of this embodiment is 600°C, and the rest is the same as Example 2.

[0046] Example 5

[0047] This embodiment provides a method for preparing α-zirconium hydrogen phosphate α-Zr(HPO4)2 ion exchange resin:

[0048] 100g of α-zirconium hydrogen phosphate ion exchange powder, 8g of aluminum dihydrogen phosphate binder, 0.1g of KCl porogen, and 10g of water were mixed and drum granulated to form spheres with a particle size ranging from 1 to 4mm. The mixture was then dried at 60°C for 3h. Finally, it was calcined in a muffle furnace at 350°C for 3.5h to obtain α-zirconium hydrogen phosphate ion exchange resin with a particle size ranging from 0.3 to 1.7mm.

[0049] Example 6

[0050] This embodiment provides a method for preparing zirconium hydrogen phosphate ion exchange resin. The difference from Example 5 is that the drying temperature is changed. The drying temperature of this embodiment is 80° C., and the rest is the same as Example 5.

[0051] Example 7

[0052] This embodiment provides a method for preparing zirconium hydrogen phosphate ion exchange resin. The difference from Example 5 is that the calcination temperature is changed. The calcination temperature of this embodiment is 400° C., and the rest is the same as Example 5.

[0053] Example 8

[0054] This embodiment provides a method for preparing a zirconium hydrogen phosphate ion exchange resin. The difference from Example 5 is that the binder is bentonite, the binder amount is 12% of the mass of the powder material, the porogen KCl amount is 1.5 g, the drying temperature is 100° C., the calcination temperature is 400° C., and the other conditions are the same as Example 5.

[0055] Adjusting the raw materials and granulation process results in different ion exchange capacities for the α-Zr(HPO4)2 ion exchange resins obtained through granulation. Two resins with different ion exchange capacities (Example 5 and Example 8) were tested according to the national standard GB / T 8144-2008, and the hydrogen ion exchange capacities were 1.28±0.18mmol / g and 0.74±0.04mmol / g, respectively. Spheres with high ion exchange capacities were selected for sintering to enhance the mechanical strength of the resin in water. Due to sintering, the hydrogen ion exchange capacity of the α-Zr(HPO4)2 ion exchange resin also decreases to a certain extent, with an experimentally determined value of 0.66±0.04mmol / g.

[0056] The ion exchange capacity of ZrO2 ion exchange resin decreases to a certain extent due to high temperature calcination. The present invention measures the ion exchange capacity of Example 2 before and after high temperature calcination. The NO3 - The ion exchange capacity is 0.10±0.02mmol / g; the NO3 - The ion exchange capacity is 0.077±0.005mmol / g.

[0057] Comparative Example 1

[0058] This comparative example provides a method for preparing zirconium hydrogen phosphate ion exchange resin. This method differs from Example 5 in that bentonite is used as the binder, the binder amount is 12% of the powder material mass, the drying temperature is 100°C, no porogen is used, and the calcination temperature is 400°C. All other conditions are the same as in Example 5. The hydrogen ion exchange capacity is 0.45±0.03 mmol / g.

[0059] Comparative Example 2

[0060] This comparative example provides a method for preparing a zirconium oxide ion exchange resin, which differs from Example 2 in that the drying temperature is changed to 25° C. and the drying time is 3 h, and the other aspects are the same as Example 2. The obtained zirconium oxide resin has poor sphericity and a high powdering rate.

[0061] Comparative Example 3

[0062] This comparative example provides a method for preparing a zirconium oxide ion exchange resin. The difference from Example 2 is that the calcination temperature is changed. The calcination temperature of this comparative example is 800°C and the calcination time is 4h. Other aspects are the same as Example 2. The obtained zirconium oxide resin NO3 - The exchange capacity is extremely low, less than 0.002mmol / g.

[0063] Comparative Example 4

[0064] This comparative example provides a method for preparing zirconium hydrogen phosphate ion exchange resin. The difference from Example 5 is that the amount of binder is changed. The amount of binder aluminum dihydrogen phosphate is 32% of the mass of the powder material, the porogen KCl is 0.4g and water is 12.2g. Other ingredients are the same as Example 5. The obtained zirconium hydrogen phosphate resin H + The exchange capacity is low, about 0.12mmol / g.

[0065] Comparative Example 5

[0066] This comparative example provides a method for preparing zirconium hydrogen phosphate ion exchange resin. The difference from Example 5 is that the calcination temperature is changed. The calcination temperature of this comparative example is 800°C. Other aspects are the same as Example 5. The obtained zirconium hydrogen phosphate resin has high strength, but H + The exchange capacity is as low as about 0.05mmol / g.

[0067] Comparative Example 6

[0068] This comparative example provides a method for preparing a zirconium hydrogen phosphate ion exchange resin, which differs from Example 5 in that no calcination treatment is performed, and the other aspects are the same as Example 5. The obtained zirconium hydrogen phosphate resin H + The exchange capacity is high (1.28±0.18mmol / g), but the strength is low. During the continuous electrodeionization process, it is severely powdered due to the continuous flushing of water flow.

[0069] The α-Zr(HPO4)2 ion exchange resins mentioned in the following application examples are all prepared in Example 5; the ZrO2 ion exchange resins are all prepared in Example 2.

[0070] Application Example 1

[0071] The desalination chamber of the EDI system was filled with granulated and sintered α-Zr(HPO4)2 ion exchange resin, and the desalination performance of the EDI system was investigated by changing the operating process parameters. The initial solution was 0.0147 mol / L sodium nitrate. When V 淡 :V 浓 =1:1, the volume of the desalted liquid and the concentrated liquid are both 350mL, V 淡 :V 浓 =9:1, the volume of desalinated liquid is 900mL and the volume of concentrated liquid is 100mL. The effects of different process parameters on desalination rate, desalination energy consumption and current efficiency are shown in Table 1.

[0072] Table 1. Desalination performance of EDI system filled with α-Zr(HPO4)2 ion exchange resin

[0073]

[0074] Application Example 2

[0075] The desalination chamber of an EDI system was filled with granulated and sintered ZrO2 ion exchange resin. The desalination performance of the EDI system was investigated by varying the operating process parameters. The effects of different process parameters on desalination rate, desalination energy consumption, and current efficiency are shown in Table 2.

[0076] Table 2. Desalination performance of ZrO2 ion exchange resin filled EDI system

[0077]

[0078]

[0079] Application Example 3

[0080] In order to investigate the ultimate desalination rate of the EDI system before and after filling with ion exchange resin, the ultimate desalination rate of the EDI system filled with different types of resins (α-Zr(HPO4)2 inorganic cation exchange resin, 732 organic cation exchange resin, ZrO2 inorganic anion exchange resin, 717 organic anion exchange resin and no resin added) was investigated under the same desalination process parameters. The results are shown in Table 3.

[0081] Table 3. Ultimate desalination rate (%) of EDI systems filled with different types of resins

[0082]

[0083] It can be seen from this that the EDI system using ion exchange resin, especially the EDI system using inorganic ion exchange resin under constant voltage, has a higher limit desalination rate of the desalination chamber solution than that of the EDI system not filled with resin.

[0084] Application Example 4

[0085] In order to investigate the performance of cation exchange resin, the desalination performance of EDI systems filled with different types of resin (α-Zr(HPO4)2 inorganic cation exchange resin, 732 organic cation exchange resin and no resin added) was compared under the same desalination process parameters. First, the desalination performance was tested at a constant current density of 2.5 mA / cm 2 The data are shown in Table 4.

[0086] Table 4. Desalination performance of EDI systems filled with different types of cation exchange resins at constant current density

[0087]

[0088] Application Example 5

[0089] To examine the performance of cation exchange resins, we compared the desalination performance of EDI systems filled with different types of resin (α-Zr(HPO4)2 inorganic cation exchange resin, 732 organic cation exchange resin, and no resin) under the same desalination process parameters. The data for this comparison, performed at a constant voltage of 5V, are shown in Table 5.

[0090] Table 5. Desalination performance of EDI systems filled with different types of cation exchange resins at constant voltage

[0091]

[0092] The table shows that while the EDI system based on the 732 strong-acid organic cation exchange resin achieved the fastest desalination rate at a constant voltage, its energy consumption was higher than that of the EDI system filled with α-Zr(HPO4)2 resin. Furthermore, the α-Zr(HPO4)2-based EDI system exhibited a higher current efficiency during the desalination process. In summary, the application of α-Zr(HPO4)2 cation exchange resin in EDI systems demonstrated excellent performance in the desalination process.

[0093] Application Example 6

[0094] In order to investigate the performance of cation exchange resin, the desalination performance of EDI systems filled with different types of resin (α-Zr(HPO4)2 inorganic cation exchange resin, 732 organic cation exchange resin and no resin added) was compared under the same desalination process parameters. 2 Desalination was performed when the initial volume ratio of desalinated liquid to concentrated liquid was 9:1. The performance comparison data is shown in Table 6.

[0095] Table 6. Desalination performance of EDI systems filled with different resins at a constant desalination:concentrate initial volume ratio of 9:1

[0096]

[0097]

[0098] Application Example 7

[0099] In order to investigate the performance of anion exchange resin, the desalination performance of EDI systems filled with different types of resin (ZrO2 inorganic anion exchange resin, 717 organic anion exchange resin and no resin added) was compared under the same desalination process parameters. 2 Desalination was performed at 4 ℃ and 1 ℃, and the data are shown in Table 7.

[0100] Table 7. Desalination performance of EDI systems filled with different resins at constant current density

[0101]

[0102] Application Example 8

[0103] To examine the performance of anion exchange resins, we compared the desalination performance of EDI systems filled with different types of resin (ZrO2 inorganic anion exchange resin, 717 organic anion exchange resin, and no resin) under the same desalination process parameters. The data for this comparison, performed at a constant voltage of 5V, is shown in Table 8.

[0104] Table 8. Desalination performance of EDI systems filled with different types of anion exchange resins at constant voltage

[0105]

[0106] The table shows that while the EDI system based on the 717 strong base organic anion exchange resin achieved the fastest desalination rate at constant voltage, its energy consumption was higher than that of the ZrO2 resin-based EDI system. Furthermore, the ZrO2-based EDI system exhibited a higher current efficiency during the desalination process. In summary, the ZrO2 anion exchange resin demonstrated excellent performance in the desalination process when applied to the EDI system.

[0107] The above disclosure is merely a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims

1. A method for preparing an inorganic ion exchange resin, characterized in that: The steps include: (1) Granulation: Mix the inorganic ion exchange powder material, inorganic binder and porogen and then granulate; (2) Dehydration and curing: After step (1), drying at 60-120°C for 0.5-3h; (3) Calcination: After step (2), calcining at 350-600° C. for 0.5-4 h to obtain an inorganic ion exchange resin; The inorganic ion exchange powder material is α-Zr(HPO4)2 or ZrO2.

2. The method for preparing an inorganic ion exchange resin according to claim 1, wherein The amount of inorganic binder used is 2-15% of the mass of inorganic ion exchange powder material; the amount of porogen used is 1-30% of the mass of inorganic binder; the amount of water added during granulation is 2-15% of the total mass of inorganic ion exchange powder material, inorganic binder and porogen.

3. The method for preparing an inorganic ion exchange resin according to claim 1, wherein The inorganic binder includes at least one of 8-20 wt% AlCl3 sol, 10-25 wt% SiO2 sol, phosphate, bentonite and montmorillonite; preferably, the phosphate is aluminum dihydrogen phosphate; The porogen is a water-soluble inorganic salt; preferably, the water-soluble inorganic salt includes at least one of NaCl, KCl, MgSO4, and Na2SO4.

4. The method for preparing an inorganic ion exchange resin according to claim 1, wherein The average particle size of the granulation in step (1) is 0.3 to 4 mm.

5. The method for preparing an inorganic ion exchange resin according to claim 1, wherein In step (3), the calcination is carried out at 350-650° C.; preferably, in step (3), the calcination is carried out at 400-550° C. for 0.5-3.5 h.

6. The inorganic ion exchange resin prepared by the method for preparing the inorganic ion exchange resin according to claims 1-5.

7. The inorganic ion exchange resin according to claim 6, characterized in that When the inorganic ion exchange powder material is α-Zr(HPO4)2, the hydrogen ion exchange capacity of the prepared inorganic cation exchange resin is 0.66±0.04mmol / g; when the inorganic ion exchange powder material is ZrO2, the nitrate ion exchange capacity of the prepared inorganic anion exchange resin is 0.077±0.005mmol / g.

8. Use of the inorganic ion exchange resin according to any one of claims 6 to 7 in continuous electrodeionization treatment of low-level waste liquid or electrodeionization treatment of low-level waste liquid.

9. The use according to claim 8, characterized in that Continuous electrodeionization treatment of low-level waste liquid or electrodeionization treatment of low-level waste liquid is carried out in a constant voltage mode; preferably, the constant voltage is a single pair of desalination-concentration chamber voltage difference of 1 to 5V.

10. The use according to claim 8, characterized in that When low-level waste liquid is treated by continuous electrodeionization or when low-level waste liquid is treated by electrodeionization, the initial volume ratio of the desalinated liquid to the concentrated liquid is 1 to 9:1; preferably, when low-level waste liquid is treated by continuous electrodeionization or when low-level waste liquid is treated by electrodeionization, the initial volume ratio of the desalinated liquid to the concentrated liquid is 1:1.

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