Modified calcium sulfite balls with high efficiency in removing active chlorine and a preparation method thereof

Abstract

This invention discloses a modified calcium sulfite ball for efficient removal of active chlorine and its preparation method, comprising the following steps: treating spherical calcium sulfite particles with tannic acid to deposit tannic acid on the surface of the spherical calcium sulfite particles, obtaining tannic acid-treated spherical calcium sulfite particles; treating the tannic acid-treated spherical calcium sulfite particles with ferrous salt to deposit ferrous ions on the surface of the tannic acid-treated spherical calcium sulfite particles, obtaining modified calcium sulfite balls for efficient removal of active chlorine. The preparation process of this invention is simple and environmentally friendly. The modified calcium sulfite balls obtained have low fluid resistance and high residual chlorine removal rate. They can be filled into filter containers for residual chlorine treatment before processes such as continuous electro-deionization (EDI) and reverse osmosis (RO), significantly improving the residual chlorine removal rate of calcium sulfite particles and suppressing the problems of calcium sulfite particle pulverization and calcium ion leakage that exist in traditional calcium sulfite dechlorination balls during use.

Description

Technical Field

[0001] This invention relates to a modified calcium sulfite ball for efficient removal of active chlorine and its preparation method, belonging to the field of water treatment technology. Background Technology

[0002] Due to their low cost, significant effectiveness, and mature technology, chlorine-containing disinfectants are widely used in water disinfection processes at wastewater treatment plants, power plants, and waterworks. However, the use of chlorine-containing disinfectants leads to an increase in residual chlorine concentration in effluent, which has a certain impact on the ecological environment. Furthermore, excessive residual chlorine can have serious adverse effects on water treatment facilities, such as causing oxidative decomposition of reverse osmosis membrane elements and oxidation / pulverization of electrodialysis packing resins. Therefore, finding efficient methods for residual chlorine removal is of significant practical value in addressing the hazards caused by chlorine-containing disinfectants.

[0003] Currently, the main methods for removing trace amounts of residual chlorine from water include activated carbon adsorption and KDF media filtration. However, these methods all have different drawbacks, limiting their practical application. Activated carbon, as an excellent adsorbent, is an effective means of removing residual chlorine and organic matter from water, but it often fails to meet the expected water purification requirements due to its short service life, difficult maintenance, and susceptibility to microbial contamination. Invention patent CN106865697A discloses a copper-zinc alloy particle for water purification, its preparation method, and a water purification filter media. This filter media uses a combination of copper-zinc alloy particles of different diameters, which maintains sufficient surface area while reducing the contact area between the copper-zinc alloy particles, thereby reducing the probability of caking. However, copper-zinc alloy filter media (KDF filter media) is expensive and unsuitable for large-scale water treatment.

[0004] Furthermore, calcium sulfite, with its reducing properties, can remove components such as combined residual chlorine, free residual chlorine, hypochlorous acid, hypochlorous acid ions, and chlorine gas through redox reactions. It is also heat-resistant and does not easily breed bacteria, thus it is also used as a filter material for removing residual chlorine from water. Ordinary calcium sulfite is a white crystalline powder; if it is directly filled into the filter container, it will cause increased fluid resistance and is easily washed away by the water flow. Granulation of calcium sulfite solves these problems to some extent.

[0005] Invention patent CN101712484A discloses a columnar calcium sulfite particle and its preparation method, which effectively solves the problem of calcium sulfite granulation. However, granular calcium sulfite dechlorination balls suffer from pulverization of calcium sulfite particles and leakage of calcium ions during actual use, and their dechlorination performance still needs further improvement. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing calcium sulfite dechlorination balls, such as particle pulverization and calcium ion leakage, and to provide a low-cost, high-efficiency modified calcium sulfite ball for removing active chlorine and its preparation method. This method involves depositing tannic acid (TA) and ferrous ions (Fe) on the surface of spherical calcium sulfite particles through a layer-by-layer self-assembly process. 2+ A nano-complex coating of TA / Fe was obtained. 2+ The coating-modified calcium sulfite spherical particles can effectively solve the problems of high cost of existing residual chlorine removal KDF filter media, calcium sulfite dechlorination ball pulverization, calcium ion leakage, and the need for further improvement in dechlorination efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0009] Spherical calcium sulfite particles were treated with tannic acid, and tannic acid was deposited on the surface of the spherical calcium sulfite particles to obtain tannic acid-treated spherical calcium sulfite particles.

[0010] Spherical calcium sulfite particles treated with tannic acid were then treated with ferrous salts to deposit ferrous ions on the surface of the tannic acid-treated spherical calcium sulfite particles, resulting in modified calcium sulfite spheres that can efficiently remove active chlorine.

[0011] Furthermore, the specific steps for treating spherical calcium sulfite particles with tannic acid are as follows: immerse the spherical calcium sulfite particles in a tannic acid solution, shake, and obtain spherical calcium sulfite particles treated with tannic acid.

[0012] Furthermore, the particle size of the spherical calcium sulfite particles ranges from 0.5 mm to 20 mm.

[0013] Furthermore, the molar concentration of the tannic acid solution is 0.1–10 mmol / L, and the pH is 2–8.

[0014] Furthermore, the oscillation time ranges from 0.5 minutes to 30 minutes.

[0015] Furthermore, the specific steps for treating spherical calcium sulfite particles with tannic acid with ferrous salt are as follows: the spherical calcium sulfite particles treated with tannic acid are immersed in a ferrous salt solution and shaken to obtain spherical calcium sulfite particles modified with a tannic acid / ferrous ion complex coating.

[0016] Furthermore, the molar concentration of the ferrous salt solution was 0.1–50 mmol / L; the shaking time was 0.5–30 minutes.

[0017] Furthermore, the ferrous salt is one or a mixture of several of ferrous sulfate, ferrous chloride, ferrous carbonate, and ferrous nitrate.

[0018] Furthermore, it also includes: repeatedly treating the modified calcium sulfite balls, which are highly effective at removing active chlorine, with tannic acid and ferrous salt.

[0019] A modified calcium sulfite ball for efficient removal of active chlorine includes a tannic acid layer and ferrous ions deposited on the surface of spherical calcium sulfite particles.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Compared with traditional calcium sulfite crystalline powder, the modified calcium sulfite spheres prepared in this invention, which are highly efficient at removing active chlorine, have a TA / Fe surface. 2+ The coating consists of spherical particles on the millimeter scale, resulting in low fluid resistance.

[0022] (2) Compared with existing granular calcium sulfite dechlorination balls, the modified calcium sulfite balls of this invention, which efficiently remove active chlorine, are coated with TA / Fe. 2+ The coating can inhibit the pulverization of calcium sulfite particles, and through TA / Fe 2+ The complexation of tannic acid (TA) components with calcium ions in the coating can prevent calcium ion leakage.

[0023] (3) Compared with existing granular calcium sulfite dechlorination balls, in addition to the reduction and removal of residual chlorine by calcium sulfite itself (chemical equations are shown in (1-1), (1-2) and (1-3)), the TA / Fe 2+ Fe in the coating 2+ It can also undergo a redox reaction with residual chlorine in water to remove residual chlorine (chemical equations are shown in (1-4), (1-5) and (1-6)), and the Fe produced by the reaction... 3+ It can be chelated by the phenolic hydroxyl functional groups in tannic acid (TA), preventing Fe from being absorbed. 3+ It enters the water body. Therefore, TA / Fe 2+ The coated modified calcium sulfite particles have a more efficient residual chlorine removal performance, with a residual chlorine removal rate of over 99%.

[0024] (4) This invention uses water as a solvent. Tannic acid is a low-cost, safe, and non-toxic raw material. The preparation process is simple and environmentally friendly. The resulting TA / Fe 2+ Coating-modified calcium sulfite can be used for residual chlorine treatment before processes such as continuous electro-deionization (EDI) and reverse osmosis (RO), without secondary pollution and ensuring water quality.

[0025] CaSO3+ Cl2+ H2O = CaSO4+ 2HCl (1-1)

[0026] CaSO3+ HClO = CaSO4+ HCl (1-2)

[0027] CaSO3+ ClO – = CaSO4+ Cl – (1-3)

[0028] Cl2+ 2Fe 2+ = 2Cl – + 2Fe 3+ (1-4)

[0029] HClO + 2Fe 2+ + H + = Cl – + 2Fe 3+ + H2O (1-5)

[0030] ClO – + 2Fe 2+ + 2H + = Cl – + 2Fe 3+ + H2O (1-6) Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0032] Figure 1 The TA / Fe in this invention 2+ A schematic diagram of the structure of coated modified calcium sulfite particles;

[0033] Figure 2 This is a process flow diagram of a method for preparing modified calcium sulfite balls for efficient removal of active chlorine according to the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0035] The present invention discloses a modified calcium sulfite ball for efficiently removing active chlorine, which is prepared from calcium sulfite balls, tannic acid and ferrous salt.

[0036] The calcium sulfite spheres can be commercially available spherical calcium sulfite particles with a particle size of 0.5 mm to 20 mm.

[0037] The ferrous salt is one or a mixture of several of ferrous sulfate (FeSO4), ferrous chloride (FeCl2), ferrous carbonate (FeCO3), and ferrous nitrate (Fe(NO3)2).

[0038] Preferably, the ferrous salt is one or a mixture of ferrous chloride (FeCl2) and ferrous nitrate (Fe(NO3)2).

[0039] See Figure 1 and Figure 2 The present invention discloses a method for preparing modified calcium sulfite balls for efficient removal of active chlorine, comprising the following steps:

[0040] S1. Immerse spherical calcium sulfite particles in tannic acid solution, shake for a period of time, filter and drain excess solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0041] S2. Spherical calcium sulfite particles treated with tannic acid were immersed in a ferrous salt solution, shaken for a period of time, filtered, excess solution was drained, and the mixture was washed with deionized water to obtain tannic acid / ferrous ion (TA / Fe). 2+ Spherical calcium sulfite particles modified with a complex coating, i.e. modified calcium sulfite spheres that efficiently remove active chlorine.

[0042] Preferably, step S3 is also included: using the TA / Fe obtained in step S2 2+ Modified spherical calcium sulfite particles, by repeating steps S1 and S2 several times, can yield spherical calcium sulfite particles with different loadings (TA / Fe) on their surface. 2+ )coating.

[0043] Finally, (TA / Fe) 2+ The complex-coated modified spherical calcium sulfite particles are vacuum dried, packaged, and ready for use.

[0044] Furthermore, in step S1 above, the molar concentration of the tannic acid solution is 0.1~10 mmol / L, the pH is 2~8, and the shaking time is 0.5 minutes~30 minutes.

[0045] Furthermore, in step S2 above, the molar concentration of the ferrous salt solution is 0.1~50 mmol / L, and the shaking time is 0.5 minutes~30 minutes.

[0046] The following are specific examples.

[0047] Example 1

[0048] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0049] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (1 mmol / L, pH = 7.0), shake for 2 minutes at room temperature, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0050] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (4 mmol / L), shaken at room temperature for 2 minutes, filtered, and excess ferrous chloride solution was drained. After soaking and washing with deionized water, tannic acid / ferrous ion (TA / Fe) was obtained. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite, namely modified calcium sulfite balls that efficiently remove active chlorine.

[0051] (3) Add 1 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0052] Example 2

[0053] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0054] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (1 mmol / L, pH = 7.0), shake for 2 minutes at room temperature, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0055] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (4 mmol / L), shaken at room temperature for 2 minutes, filtered, and excess ferrous chloride solution was drained. After soaking and washing with deionized water, tannic acid / ferrous ion (TA / Fe) was obtained. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0056] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for two more cycles to obtain three TA / Fe phosphate particles. 2+ Cyclic modified calcium sulfite particles.

[0057] (4) Add 3 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0058] Example 3

[0059] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0060] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (1 mmol / L, pH = 7.0), shake for 2 minutes at room temperature, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0061] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (4 mmol / L), shaken at room temperature for 2 minutes, filtered, and excess ferrous chloride solution was drained. After soaking and washing with deionized water, tannic acid / ferrous ion (TA / Fe) was obtained. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0062] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0063] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0064] Example 4

[0065] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0066] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (10 mmol / L, pH = 7.0), shake at room temperature for 2 minutes, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0067] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (40 mmol / L), shaken at room temperature for 2 minutes, filtered, and excess ferrous chloride solution was drained. After soaking and washing with deionized water, tannic acid / ferrous ion (TA / Fe) was obtained. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0068] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0069] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0070] Example 5

[0071] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0072] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (10 mmol / L, pH = 7.0), shake at room temperature for 10 minutes, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0073] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (40 mmol / L), shaken at room temperature for 10 minutes, filtered to remove excess ferrous chloride solution, and then soaked and washed with deionized water to obtain tannic acid / ferrous ion (TA / Fe) ions. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0074] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0075] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0076] Example 6

[0077] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0078] (1) Immerse spherical calcium sulfite particles (particle size 18 mm ~ 20 mm) in tannic acid solution (0.1 mmol / L, pH = 4.0), shake at room temperature for 20 minutes, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0079] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous sulfate solution (0.1 mmol / L), shaken at room temperature for 10 minutes, filtered to remove excess ferrous chloride solution, and then soaked and washed with deionized water to obtain tannic acid / ferrous ion (TA / Fe) ions. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0080] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0081] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0082] Example 7

[0083] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0084] (1) Immerse spherical calcium sulfite particles (particle size 0.5 mm ~ 0.6 mm) in tannic acid solution (0.1 mmol / L, pH = 2.0), shake at room temperature for 30 minutes, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0085] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a solution (0.1 mmol / L) containing ferrous carbonate and ferrous nitrate in a molar ratio of 1:10. The solution was shaken at room temperature for 30 minutes, filtered, and excess ferrous chloride solution was drained. The particles were then soaked and washed with deionized water to obtain tannic acid / ferrous ion (TA / Fe) ions. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0086] (3) Use the 1 TA / Fe obtained in step (2) 2+ The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0087] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0088] Example 8

[0089] A method for preparing modified calcium sulfite balls for efficient removal of active chlorine includes the following steps:

[0090] (1) Immerse spherical calcium sulfite particles (particle size 0.6 mm ~ 0.8 mm) in tannic acid solution (3 mmol / L, pH = 8.0), shake at room temperature for 0.5 minutes, filter and drain excess tannic acid solution to obtain spherical calcium sulfite particles treated with tannic acid (TA);

[0091] (2) Tannic acid-treated spherical calcium sulfite particles were immersed in a ferrous chloride solution (10 mmol / L), shaken at room temperature for 0.5 minutes, filtered to remove excess ferrous chloride solution, and then soaked and washed with deionized water to obtain tannic acid / ferrous ion (TA / Fe) ions. 2+ Spherical calcium sulfite particles modified with a complex coating are denoted as 1 TA / Fe 2+ Cyclic modified calcium sulfite.

[0092] (3) Use the 1 TA / Fe obtained in step (2) 2+The modified calcium sulfite particles were recycled, and steps (1) and (2) were repeated for another 4 cycles to obtain 5 TA / Fe granules. 2+ Cyclic modified calcium sulfite particles.

[0093] (4) Add 5 TA / Fe 2+ The cyclically modified spherical calcium sulfite granules are vacuum dried, packaged, and ready for use.

[0094] Comparative Example 1

[0095] Commercially available calcium sulfite spheres (particle size 0.6 mm ~ 0.8 mm) are free of tannic acid / ferrous ions (TA / Fe). 2+ Complex coating modification.

[0096] The modified calcium sulfite balls prepared in Examples 1 to 8 were compared with those in Comparative Example 1 for residual chlorine removal performance. The tests were conducted under the conditions shown in Table 1 below, and the results are shown in Table 2.

[0097] Table 1

[0098]

[0099] Table 2

[0100]

[0101] Compared to Comparative Example 1, after treatment with tannic acid / ferrous ions (TA / Fe) 2+ The residual chlorine removal rate of the coated spherical calcium sulfite particles was significantly improved.

[0102] Comparing Examples 1, 2, and 3, after 1, 3, and 5 TA / Fe... 2+ The residual chlorine removal rates of the recycled modified calcium sulfite were 90.3%, 98.4%, and 99.8%, respectively, indicating that with the increase in tannic acid / ferrous ion (TA / Fe) ratio, the chlorine removal rate increased. 2+ With the increase of the number of cycles of modification, the residual chlorine removal rate increases rapidly and tends to stabilize.

[0103] Comparing Examples 4, 5, and 8, the results after 5 TA / Fe... 2+ The soaking time in the cyclic modified calcium sulfite particles, tannic acid solution, and ferrous salt solution had little effect on the residual chlorine removal rate, indicating that the complexation rate of tannic acid and ferrous ions was very fast, and could be completed within 0.5 minutes.

[0104] Comparing Examples 6, 7, and 8, it is evident that the pH of the tannic acid solution has a significant impact on the residual chlorine removal rate. A decrease in pH can lead to a drop in the residual chlorine removal rate. This may be because, under lower pH conditions (pH ≤ 2), the phenolic hydroxyl groups in the tannic acid molecule tend to protonate, reducing their ability to coordinate and complex with ferrous ions, thus affecting the TA / Fe ratio. 2+ Coating formation; however, under excessively high pH conditions (pH≥9), ferrous ions readily hydrolyze to form ferrous hydroxide, which is also detrimental to TA / Fe 2+ Coating formation. Therefore, efficient TA / Fe formation is only possible within a suitable pH range. 2+ coating.

[0105] In terms of overall performance, Example 4 is more ideal, with both high dechlorination efficiency and relatively short preparation time.

[0106] The preparation process of this invention is simple and environmentally friendly. The modified calcium sulfite balls obtained have low fluid resistance and high residual chlorine removal rate. They can be filled into filter containers for residual chlorine treatment before processes such as continuous electro-deionization (EDI) and reverse osmosis (RO). Furthermore, they significantly improve the residual chlorine removal rate of calcium sulfite particles and can suppress the problems of calcium sulfite particle pulverization and calcium ion leakage that exist in traditional calcium sulfite dechlorination balls during use.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing modified calcium sulfite balls for efficient removal of active chlorine, characterized in that, Includes the following steps: Spherical calcium sulfite particles were treated with tannic acid, and tannic acid was deposited on the surface of the spherical calcium sulfite particles to obtain tannic acid-treated spherical calcium sulfite particles. Spherical calcium sulfite particles treated with tannic acid were then treated with ferrous salts to deposit ferrous ions on the surface of the tannic acid-treated spherical calcium sulfite particles, resulting in modified calcium sulfite spheres that can efficiently remove active chlorine. The specific steps for treating spherical calcium sulfite particles with tannic acid are as follows: immerse the spherical calcium sulfite particles in a tannic acid solution and shake for 0.5 to 30 minutes to obtain spherical calcium sulfite particles treated with tannic acid. The specific steps for treating spherical calcium sulfite particles with tannic acid with ferrous salt are as follows: the spherical calcium sulfite particles treated with tannic acid are immersed in a ferrous salt solution and shaken for 0.5 minutes to 30 minutes to obtain spherical calcium sulfite particles modified with tannic acid / ferrous ion complex coating. It also includes the step of repeatedly treating modified calcium sulfite balls, which are highly effective at removing active chlorine, with tannic acid and ferrous salt.

2. The method for preparing modified calcium sulfite balls for efficient removal of active chlorine according to claim 1, characterized in that, The particle size of the spherical calcium sulfite particles ranges from 0.5 mm to 20 mm.

3. The method for preparing modified calcium sulfite balls for efficient removal of active chlorine according to claim 2, characterized in that, The molar concentration of the tannic acid solution is 0.1~10 mmol / L, and the pH is 2~8.

4. The method for preparing modified calcium sulfite balls for efficient removal of active chlorine according to claim 1, characterized in that, The molar concentration of the ferrous salt solution is 0.1~50 mmol / L.

5. The method for preparing modified calcium sulfite balls for efficient removal of active chlorine according to claim 1, characterized in that, Ferrous salts are one or a mixture of several of ferrous sulfate, ferrous chloride, ferrous carbonate, and ferrous nitrate.

6. A modified calcium sulfite ball for efficient removal of active chlorine prepared according to any one of claims 1-5, characterized in that, This includes a tannic acid layer and ferrous ions deposited on the surface of spherical calcium sulfite particles.

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