Modified calcium sulfite ball capable of efficiently removing active chlorine and preparation method of modified calcium sulfite ball

Abstract

The invention discloses a modified calcium sulfite ball capable of efficiently removing active chlorine and a preparation method thereof, and the preparation method comprises the following steps: treating spherical calcium sulfite particles with tannic acid, and depositing tannic acid on the surfaces of the spherical calcium sulfite particles to obtain tannic acid treated spherical calcium sulfite particles; treating the spherical calcium sulfite particles treated by the tannic acid with ferrite, and depositing ferrous ions on the surfaces of the spherical calcium sulfite particles treated by the tannic acid to obtain the modified calcium sulfite balls capable of efficiently removing the active chlorine. The preparation process is simple and environment-friendly, the prepared modified calcium sulfite balls are small in fluid resistance and high in residual chlorine removal rate and can be filled into a filter container to be applied to residual chlorine treatment before procedures such as continuous electrodeionization (EDI) and reverse osmosis (RO), the residual chlorine removal rate of calcium sulfite particles is remarkably increased, and the method is suitable for industrial production. And the problems of pulverization of calcium sulfite particles and leakage of calcium ions in use of the traditional calcium sulfite dechlorination ball can be inhibited.

Description

Technical Field

[0001] The present invention relates to a modified calcium sulfite ball for efficiently removing active chlorine and a preparation method thereof, belonging to the technical field of water treatment. Background Art

[0002] Due to advantages such as low price, remarkable effect, and mature process, chlorine-containing disinfectants are widely used in the water disinfection treatment process in fields such as wastewater treatment plants, power plants, and waterworks. However, the use of chlorine-containing disinfectants will increase the residual chlorine concentration in the water body, causing certain impacts on the ecological environment; in addition, excessive residual chlorine will also have serious adverse effects on water treatment facilities, such as causing the oxidation and decomposition of reverse osmosis membrane elements and the oxidation / pulverization of electrodialysis filling resins. Therefore, seeking an efficient method for removing residual chlorine has important practical application value for solving the problem of residual chlorine hazards caused by chlorine-containing disinfectants.

[0003] Currently, the main methods for removing trace residual chlorine from water include activated carbon adsorption method, KDF medium filtration method, etc. However, these methods all have different disadvantages, which limit their application in practice. Activated carbon, as an excellent adsorbent, is an effective means for removing residual chlorine and organic matter in water, but it often fails to meet the expected water purification requirements due to its short service life, difficult maintenance, and easy microbial contamination. The invention patent CN106865697A discloses a copper-zinc alloy particle for water purification, a preparation method thereof, and a water purification filter material. This filter material adopts a combination of copper-zinc alloy particles with different diameters, so that while the copper-zinc alloy particles maintain a sufficient surface area, the contact area between the copper-zinc alloy particles is reduced, thereby reducing the probability of caking. However, the copper-zinc alloy filter material (KDF filter material) is expensive and not suitable for large-scale water treatment.

[0004] In addition, calcium sulfite with reducibility can remove components such as combined residual chlorine, free residual chlorine, hypochlorous acid, hypochlorite ions, and chlorine through redox reactions, and can withstand high temperatures and is not prone to bacterial growth, so it is also used as a filter material for removing residual chlorine in water. Ordinary calcium sulfite is a white crystalline powder. If it is directly filled in a filtration container, it will cause an increase in fluid resistance and be easily washed away by water flow. The granulation of calcium sulfite solves the above problems to a certain extent.

[0005] The invention patent CN101712484A discloses a calcium sulfite particle in a columnar structure and a preparation method thereof, which well solves the problem of calcium sulfite granulation. However, in the actual use process of granular calcium sulfite dechlorination balls, there are problems such as the pulverization of calcium sulfite particles and the leakage of calcium ions, and its dechlorination performance still needs to be further improved. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of existing calcium sulfite chlorine removal balls, namely particle pulverization and calcium ion leakage, and to provide a modified calcium sulfite ball with low cost and high efficiency in removing active chlorine and a preparation method thereof. This method deposits a nano complex coating of tannic acid (TA) and ferrous ions (Fe 2+ ) on the surface of spherical calcium sulfite particles through a layer-by-layer self-assembly method to obtain calcium sulfite spherical particles modified with a TA / Fe 2+ coating, which can effectively solve the problems of high cost of existing KDF filter materials for residual chlorine removal, pulverization of calcium sulfite chlorine removal balls, calcium ion leakage, and the need to further improve chlorine removal efficiency.

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

[0008] A preparation method of a modified calcium sulfite ball for efficiently removing active chlorine, comprising the following steps:

[0009] Treat 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;

[0010] Treat 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 a modified calcium sulfite ball for efficiently removing active chlorine.

[0011] Further, the specific steps of treating spherical calcium sulfite particles with tannic acid are: Immerse the spherical calcium sulfite particles in a tannic acid solution and shake to obtain tannic acid-treated spherical calcium sulfite particles.

[0012] Further, the particle size of the spherical calcium sulfite particles is 0.5 mm to 20 mm.

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

[0014] Further, the shaking time is 0.5 minutes to 30 minutes.

[0015] Further, the specific steps of treating the tannic acid-treated spherical calcium sulfite particles with ferrous salt are: Immerse the tannic acid-treated spherical calcium sulfite particles in a ferrous salt solution and shake to obtain spherical calcium sulfite particles modified with a tannic acid / ferrous ion complex coating.

[0016] Further, the molar concentration of the ferrous salt solution is 0.1 to 50 mmol / L; the shaking time is 0.5 minutes to 30 minutes.

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

[0018] Further, it also includes: repeating the steps of treating the modified calcium sulfite balls with high-efficiency active chlorine removal with tannic acid treatment and ferrous salt treatment.

[0019] A modified calcium sulfite ball with high-efficiency active chlorine removal 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 surface of the modified calcium sulfite ball with high-efficiency active chlorine removal prepared by the present invention is a TA / Fe 2+ coating, which is spherical particles on the millimeter scale and has a lower fluid resistance.

[0022] (2) Compared with the existing granular calcium sulfite chlorine removal balls, the surface of the modified calcium sulfite ball with high-efficiency active chlorine removal in the present invention is coated with TA / Fe 2+ coating, which can inhibit the pulverization of calcium sulfite particles, and the complexation of tannic acid (TA) component in the TA / Fe 2+ coating with calcium ions can avoid the leakage of calcium ions.

[0023] (3) Compared with the existing granular calcium sulfite chlorine removal 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)), Fe in the TA / Fe 2+ coating 2+ can also react with residual chlorine in water through oxidation-reduction reaction to achieve the removal of residual chlorine (chemical equations are shown in (1-4), (1-5) and (1-6)), and the generated Fe 3+ can be chelated by the phenolic hydroxyl functional groups in tannic acid (TA) to avoid Fe 3+ from entering the water body. Therefore, the TA / Fe 2+ coated modified calcium sulfite particles have more efficient residual chlorine removal performance, and the residual chlorine removal rate reaches more than 99%.

[0024] (4) The present invention uses water as a solvent, the raw material of tannic acid is cheap, safe and non-toxic, the preparation process is simple and environmentally friendly, and the prepared TA / Fe 2+ coated modified calcium sulfite can be used for residual chlorine treatment before processes such as continuous electrodeionization (EDI) and reverse osmosis (RO), without secondary pollution and can ensure water quality.

[0025] CaSO 3 + Cl 2 + H 2 O = CaSO 4+ 2HCl (1-1)

[0026] CaSO 3 + HClO = CaSO 4 + HCl (1-2)

[0027] CaSO 3 +ClO – =CaSO 4 +Cl – (1-3)

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

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

[0030] ClO – + 2Fe 2+ + 2H + = Cl – + 2Fe 3+ + H 2 O (1-6) Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, obtaining other drawings based on these drawings still belongs to the scope of the present invention.

[0032] Figure 1 Schematic diagram of the structural composition of TA / Fe 2+ coated modified calcium sulfite particles in the present invention;

[0033] Figure 2 Process flow chart of the preparation method of a modified calcium sulfite ball with high-efficiency removal of active chlorine in the present invention. Detailed Embodiments

[0034] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them, and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0035] A modified calcium sulfite ball for efficiently removing active chlorine in the present invention is prepared from calcium sulfite balls, tannic acid and ferrous salts.

[0036] The calcium sulfite balls can be commercial spherical calcium sulfite particles, and the particle size of the particles is 0.5 mm to 20 mm.

[0037] The ferrous salt is ferrous sulfate (FeSO 4 )、ferrous chloride (FeCl 2 )、ferrous carbonate (FeCO 3 ) and ferrous nitrate (Fe(NO 3 ) 2 ) or a mixture of several of them.

[0038] Preferably, the ferrous salt is a mixture of one or two of ferrous chloride (FeCl 2 ) and ferrous nitrate (Fe(NO 3 ) 2 ).

[0039] See Figure 1 and Figure 2 , a preparation method of a modified calcium sulfite ball for efficiently removing active chlorine in the present invention includes the following steps:

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

[0041] S2. Immerse the spherical calcium sulfite particles treated with tannic acid in the ferrous salt solution, shake for a period of time, filter and drain the excess solution, and after washing with deionized water, obtain the spherical calcium sulfite particles modified with a tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, that is, the modified calcium sulfite ball for efficiently removing active chlorine.

[0042] Preferably, it further includes step S3: using the TA / Fe obtained in step S2 2+Modified spherical calcium sulfite particles. By continuing to repeat steps S1 and S2 for several cycles, coatings with different loadings of (TA / Fe 2+ ) can be obtained on the surface of the spherical calcium sulfite particles.

[0043] Finally, the spherical calcium sulfite particles modified with the (TA / Fe 2+ ) complex coating are vacuum dried, packaged, and reserved for use.

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

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

[0046] The following are specific examples.

[0047] Example 1

[0048] A method for preparing modified calcium sulfite spheres for efficient removal of active chlorine, comprising the following steps:

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

[0050] (2) Immerse the tannic acid-treated spherical calcium sulfite particles into a ferrous chloride solution (4 mmol / L), oscillate at room temperature for 2 minutes, filter, and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with a tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as spherical calcium sulfite modified by 1 TA / Fe 2+ cycle modification, i.e., modified calcium sulfite spheres for efficient removal of active chlorine.

[0051] (3) Vacuum dry the spherical calcium sulfite particles modified by 1 TA / Fe 2+ cycle modification, package, and reserve for use.

[0052] Example 2

[0053] A method for preparing modified calcium sulfite spheres for efficient removal of active chlorine, comprising the following steps:

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

[0055] (2) Immerse the spherical calcium sulfite particles treated with tannic acid into ferrous chloride solution (4 mmol / L), shake at room temperature for 2 minutes, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as 1 TA / Fe 2+ cyclic modified calcium sulfite.

[0056] (3) Use 1 TA / Fe 2+ cyclic modified calcium sulfite particle obtained in step (2), continue to repeat the above steps (1) and (2), and perform 2 more cycles to obtain 3 TA / Fe 2+ cyclic modified calcium sulfite particles.

[0057] (4) After vacuum drying the 3 TA / Fe 2+ cyclic modified spherical calcium sulfite particles, package and reserve for use.

[0058] Example 3

[0059] A preparation method of modified calcium sulfite balls for efficient removal of active chlorine, comprising the following steps:

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

[0061] (2) Immerse the spherical calcium sulfite particles treated with tannic acid into ferrous chloride solution (4 mmol / L), shake at room temperature for 2 minutes, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as 1 TA / Fe 2+ cyclic modified calcium sulfite.

[0062] (3) Use 1 TA / Fe 2+ cyclic modified calcium sulfite particle obtained in step (2), continue to repeat the above steps (1) and (2), and perform 4 more cycles to obtain 5 TA / Fe 2+ cyclic modified calcium sulfite particles.

[0063] (4) Immerse 5 TA / Fe 2+ The spherical calcium sulfite particles modified by cyclic modification are dried in vacuum, packaged and reserved for use.

[0064] Example 4

[0065] A preparation method of modified calcium sulfite balls for efficiently removing active chlorine, comprising the following steps:

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

[0067] (2) Immerse the tannic acid-treated spherical calcium sulfite particles into ferrous chloride solution (40 mmol / L), shake for 2 minutes at room temperature, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as 1 TA / Fe 2+ Calcium sulfite modified by cyclic modification.

[0068] (3) Use the 1 TA / Fe 2+ spherical calcium sulfite particles modified by cyclic modification obtained in step (2), continue to repeat the above steps (1) and (2), and perform 4 more cycles to obtain 5 TA / Fe 2+ spherical calcium sulfite particles modified by cyclic modification.

[0069] (4) Immerse 5 TA / Fe 2+ The spherical calcium sulfite particles modified by cyclic modification are dried in vacuum, packaged and reserved for use.

[0070] Example 5

[0071] A preparation method of modified calcium sulfite balls for efficiently removing active chlorine, comprising the following steps:

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

[0073] (2) Immerse the tannic acid-treated spherical calcium sulfite particles into ferrous chloride solution (40 mmol / L), shake for 10 minutes at room temperature, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with tannic acid / ferrous ion (TA / Fe2+ ) Spherical calcium sulfite particles modified with a complex coating, denoted as 1 TA / Fe 2+ Calcium sulfite modified by cycling

[0074] (3) Use the 1 TA / Fe 2+ Calcium sulfite particles modified by cycling, continue to repeat the above steps (1) and (2), and perform 4 more cycles to obtain 5 TA / Fe 2+ Calcium sulfite particles modified by cycling

[0075] (4) After vacuum drying the 5 TA / Fe 2+ Calcium sulfite spherical particles modified by cycling, they are packaged and reserved

[0076] Example 6

[0077] A preparation method of modified calcium sulfite spheres for efficiently removing active chlorine, comprising the following steps:

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

[0079] (2) Immerse the tannic acid-treated spherical calcium sulfite particles into ferrous sulfate solution (0.1 mmol / L), shake at room temperature for 10 minutes, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain tannic acid / ferrous ion (TA / Fe 2+ ) Spherical calcium sulfite particles modified with a complex coating, denoted as 1 TA / Fe 2+ Calcium sulfite modified by cycling

[0080] (3) Use the 1 TA / Fe 2+ Calcium sulfite particles modified by cycling, continue to repeat the above steps (1) and (2), and perform 4 more cycles to obtain 5 TA / Fe 2+ Calcium sulfite particles modified by cycling

[0081] (4) After vacuum drying the 5 TA / Fe 2+ Calcium sulfite spherical particles modified by cycling, they are packaged and reserved

[0082] Example 7

[0083] A preparation method of modified calcium sulfite spheres for efficiently removing active chlorine, comprising the following steps:

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

[0085] (2) Immerse the spherical calcium sulfite particles treated with tannic acid into a solution (0.1 mmol / L) containing ferrous carbonate and ferrous nitrate with a molar ratio of 1:10, shake at room temperature for 30 minutes, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with a tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as 1 TA / Fe 2+ cyclically modified calcium sulfite.

[0086] (3) Use 1 TA / Fe 2+ cyclically modified calcium sulfite particles obtained in step (2), continue to repeat the above steps (1) and (2), and perform 4 more cycles to obtain 5 TA / Fe 2+ cyclically modified calcium sulfite particles.

[0087] (4) After vacuum drying the 5 TA / Fe 2+ cyclically modified spherical calcium sulfite particles, package and set aside for use.

[0088] Example 8

[0089] A preparation method of modified calcium sulfite balls for efficiently removing active chlorine, comprising the following steps:

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

[0091] (2) Immerse the spherical calcium sulfite particles treated with tannic acid into ferrous chloride solution (10 mmol / L), shake at room temperature for 0.5 minutes, filter and drain the excess ferrous chloride solution, soak and wash with deionized water to obtain spherical calcium sulfite particles modified with a tannic acid / ferrous ion (TA / Fe 2+ ) complex coating, denoted as 1 TA / Fe 2+ cyclically modified calcium sulfite.

[0092] (3) Use 1 TA / Fe 2+The calcium sulfite particles modified by cycling are used to repeat the above steps (1) and (2) for another 4 cycles to obtain 5 TA / Fe 2+ Calcium sulfite particles modified by cycling.

[0093] (4) Five TA / Fe 2+ After vacuum drying, the spherical calcium sulfite particles modified by cycling are packaged and reserved for use.

[0094] Comparative Example 1

[0095] Commercially available calcium sulfite balls (particle size: 0.6 mm - 0.8 mm), without complex coating modification by tannic acid / ferrous ion (TA / Fe 2+ ).

[0096] The modified calcium sulfite balls prepared in Examples 1 to 5 above and Comparative Example 1 are compared for chlorine residual removal performance, and the tests are carried out according to the conditions shown in Table 1 below, and the results are shown in Table 2.

[0097] Table 1

[0098] Temperature pH Residual chlorine concentration Flow rate 25℃ 6.8～7.1 0.6 ppm 1.8m / s

[0099] Table 2

[0100]

[0101] Compared with Comparative Example 1, the chlorine residual removal rates of the spherical calcium sulfite particles modified by tannic acid / ferrous ion (TA / Fe 2+ ) coating are significantly improved.

[0102] Comparing Examples 1, 2 and 3, the chlorine residual removal rates of calcium sulfite modified by 1, 3, 5 TA / Fe 2+ cycles are 90.3%, 98.4% and 99.8% respectively, indicating that with the increase of the cycling modification times of tannic acid / ferrous ion (TA / Fe 2+ ), the chlorine residual removal rate increases rapidly and tends to be stable.

[0103] Comparing Examples 4, 5 and 8, for the calcium sulfite particles modified by 5 TA / Fe 2+ cycles, the soaking time in tannic acid solution and ferrous salt solution has little effect on the chlorine residual removal rate, indicating that the complexation rate of tannic acid and ferrous ion is very fast and can be completed within 0.5 minutes.

[0104] Comparing Comparative Example 6, Example 7 and Example 8, it shows that the pH of the tannic acid solution has an important influence on the residual chlorine removal rate, which will lead to a decrease in the residual chlorine removal rate. This may be because under lower pH conditions (pH ≤ 2), the phenolic hydroxyl groups in the tannic acid molecules tend to be protonated, reducing their ability to coordinate and complex with ferrous ions, thus affecting the formation of the TA / Fe 2+ coating; while under too high pH conditions (pH ≥ 9), ferrous ions are prone to hydrolysis to form ferrous hydroxide, which is also not conducive to the formation of the TA / Fe 2+ coating. Therefore, only within an appropriate pH range can the TA / Fe 2+ coating be efficiently formed.

[0105] In terms of comprehensive performance, Example 4 is relatively ideal, having both a very high dechlorination efficiency and a relatively short time consumed in the preparation process.

[0106] The preparation process of the present invention is simple and environmentally friendly. The prepared modified calcium sulfite balls have a small fluid resistance and a high residual chlorine removal rate. They can be filled in a filtration container and applied to the residual chlorine treatment before processes such as continuous electrodeionization (EDI) and reverse osmosis (RO). Moreover, it significantly improves the residual chlorine removal rate of calcium sulfite particles and can inhibit the problems of calcium sulfite particle pulverization and calcium ion leakage existing in the use of traditional calcium sulfite chlorine removal balls.

[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 them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for preparing modified calcium sulfite balls for efficiently removing active chlorine, characterized in that: The following steps are involved: treating the spherical calcium sulfite particles with tannic acid, depositing the tannic acid on the surface of the spherical calcium sulfite particles, and obtaining spherical calcium sulfite particles treated with tannic acid; The spherical calcium sulfite particles treated with tannic acid are treated with ferrous salt, and ferrous ions are deposited on the surface of the spherical calcium sulfite particles treated with tannic acid to obtain modified calcium sulfite balls that can efficiently remove active chlorine.

2. The method for preparing modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that: The specific steps of treating the spherical calcium sulfite particles with tannic acid are as follows: immersing the spherical calcium sulfite particles in a tannic acid solution, shaking, and obtaining spherical calcium sulfite particles treated with tannic acid.

3. The preparation method of modified calcium sulfite balls for efficiently removing active chlorine according to claim 1 or 2, characterized in that, The particle size of the spherical calcium sulfite particles is 0.5 mm to 20 mm.

4. The method for preparing modified calcium sulfite balls for efficiently removing 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.

5. The preparation method of modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that, The shaking time is 0.5 minutes to 30 minutes.

6. The method for preparing modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that: The specific steps of treating the spherical calcium sulfite particles treated with tannic acid with ferrous salt are as follows: immersing the spherical calcium sulfite particles treated with tannic acid in a ferrous salt solution, shaking, and obtaining spherical calcium sulfite particles modified with a tannic acid / ferrous ion complex coating.

7. The method for preparing modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that: The molar concentration of the ferrous salt solution is 0.1 to 50 mmol / L; the shaking time is 0.5 to 30 minutes.

8. The method for preparing modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that: The ferrous salt is one or a mixture of ferrous sulfate, ferrous chloride, ferrous carbonate and ferrous nitrate.

9. The method for preparing modified calcium sulfite balls for efficiently removing active chlorine according to claim 1, characterized in that: Also includes: The modified calcium sulfite balls which can remove active chlorine efficiently are repeatedly treated with tannic acid and ferrous salt.

10. A modified calcium sulfite ball for efficiently removing active chlorine prepared according to the method according to any one of claims 1 to 9, characterized in that: The invention comprises a tannic acid layer and ferrous ions deposited on the surface of spherical calcium sulfite particles.

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