Slow-release dechlorination microcapsule as well as preparation method and application thereof

Abstract

The invention relates to the technical field of water treatment, in particular to a slow-release dechlorination microcapsule and a preparation method and application thereof.The preparation method of the slow-release dechlorination microcapsule comprises the steps that 1, an aqueous solution of sodium sulfite and an aqueous solution of ethyl cellulose, ethyl acetate and polyethylene glycol are provided; step 2, dissolving the ethyl cellulose in the ethyl acetate, adding the aqueous solution of sodium sulfite under the condition of 4-6 DEG C, and stirring to obtain a single emulsion; 3, immediately adding the aqueous solution of polyethylene glycol into the single emulsion, and stirring to obtain a multiple emulsion; and step 4, carrying out standing treatment on the multiple emulsion in a vacuum environment, carrying out reduced-pressure suction filtration treatment, and sequentially carrying out water washing treatment and drying treatment on the obtained solid, so as to obtain the slow-release dechlorination microcapsule. The dechlorination effect can be prolonged, the continuous stability in the water treatment process is ensured, and the utilization rate of sodium sulfite and the dechlorination efficiency can also be improved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a slow-release chlorine-removing microcapsule and a preparation method and application thereof. Background Art

[0002] Residual chlorine is one of the important indicators of conventional drinking water disinfectants. According to GB 5749-2022 "Sanitary Standards for Drinking Water", residual chlorine plays a key disinfecting role in tap water. Free residual chlorine (ClO-, HClO, Cl2) can effectively kill microorganisms in tap water and pipe networks through its strong oxidizing properties, preventing the spread of certain infectious diseases mediated by water. However, studies in recent years have shown that there is a close relationship between chloride in drinking water and the risk of cancer. The International Agency for Research on Cancer (IARC) pointed out in reports in 1982, 1987 and 1999 that long-term intake of drinking water containing chloride may increase the risk of cancer.

[0003] Sodium sulfite (Na 2 SO 3 ) is a reducing compound that can undergo redox reactions with free residual chlorine. Therefore, sodium sulfite is often used as an effective residual chlorine adsorbent. However, if ordinary sodium sulfite is directly filled into a filter container, it is very easy to cause it to dissolve quickly during the flow of raw water and cannot be fully utilized, resulting in low chlorine removal efficiency. In addition, due to the high water solubility of sodium sulfite, it is difficult to achieve a continuous and stable chlorine removal effect when directly used in the water treatment process, which is likely to cause waste of resources and unstable treatment effects.

[0004] In view of the shortcomings of existing dechlorination products, the present invention provides a highly efficient, stable and economical sustained-release dechlorination microcapsule and a preparation method and application thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a slow-release chlorine-removing microcapsule and a preparation method and application thereof in view of the deficiencies in the prior art;

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a method for preparing a sustained-release chlorine-removing microcapsule, the steps comprising:

[0008] Step 1, providing an aqueous solution of sodium sulfite, ethyl cellulose, ethyl acetate, and an aqueous solution of polyethylene glycol;

[0009] Step 2, dissolving the ethyl cellulose in the ethyl acetate, adding the aqueous solution of sodium sulfite at 4° C.-6° C., and stirring to obtain a single emulsion;

[0010] Step 3, immediately adding the aqueous solution of polyethylene glycol into the single emulsion and stirring to obtain a double emulsion;

[0011] Step 4: After the double emulsion is allowed to stand in a vacuum environment, it is filtered under reduced pressure, and the obtained solid is washed with water and dried in sequence to obtain the slow-release chlorine-removing microcapsules.

[0012] Furthermore, in the step 1,

[0013] The mass fraction of the aqueous solution of sodium sulfite is 75%-80%;

[0014] The mass fraction of the polyethylene glycol aqueous solution is 0.9%-1%.

[0015] Furthermore, in the step 2, the mass ratio of the ethyl cellulose to the ethyl acetate is 1:(10-20).

[0016] Furthermore, the stirring conditions in step 2 include: a stirring speed of 1700 r / min-1800 r / min, and a stirring time of 20 min-25 min;

[0017] The stirring conditions in step three include: a stirring speed of 1500 r / min-1600 r / min, and a stirring time of 20 min-25 min.

[0018] Furthermore, the standing treatment time in step 4 is 2h-3h, and the drying treatment temperature is 40°C-60°C.

[0019] Furthermore, the molecular weight of the solute polyethylene glycol in the aqueous solution of polyethylene glycol is 3600-4400.

[0020] A sustained-release chlorine-removing microcapsule prepared by the above-mentioned preparation method of the sustained-release chlorine-removing microcapsule.

[0021] An application of the above-mentioned slow-release chlorine-removing microcapsule in purifying water resources.

[0022] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art:

[0023] The present invention adopts non-toxic and inexpensive water-insoluble ethyl cellulose as the main capsule wall material of the microcapsule, and adds ethyl acetate which is partially soluble in water to adjust the oil-water interface mass transfer of the emulsion. This combination not only improves the stability of the emulsion, but also is more conducive to the controlled slow release of sodium sulfite as the capsule core, thereby prolonging the dechlorination effect, ensuring the continuous stability in the water treatment process, and also improving the utilization rate of sodium sulfite and the dechlorination efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a comparison chart of the residual chlorine removal rate of the slow-release chlorine-removing microcapsules of Example 1 of the present invention and the sodium sulfite powder of the comparative example. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention will be described in detail below.

[0026] Unless otherwise defined, technical or scientific terms used in the claims and the specification shall have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0027] The words "include" or similar words used in the patent application specification and claims of the present invention mean that the items appearing before "include" include the items listed after "include" or their equivalents, and do not exclude other items.

[0028] The numerical values ​​mentioned in the present invention include all numerical values ​​that increase from low to high by one unit, assuming that there are at least two units between any lower value and the higher value. For example, if a component or a physical quantity is said to be from 1 to 100, 10 to 90 is more preferred, and 20 to 80 is the most preferred, it is intended to express that values ​​such as 5 to 95, 14 to 76, 23 to 67, 32 to 58, 41 to 49 are clearly listed in this specification; for values ​​less than 1, 0.0001, 0.001, 0.01 or 0.1 are considered to be more suitable as a unit. The above examples are for illustrative purposes only. In fact, all numerical combinations between the lowest value and the highest value listed are deemed to be clearly listed in this specification in a similar manner.

[0029] Example 1

[0030] This embodiment provides a method for preparing sustained-release chlorine-removing microcapsules.

[0031] Step 1, providing an aqueous solution of sodium sulfite, ethyl cellulose, ethyl acetate, and an aqueous solution of polyethylene glycol;

[0032] The preparation of the aqueous solution of sodium sulfite is as follows: 80 g of sodium sulfite is dissolved in 100 g of water to obtain an aqueous solution of sodium sulfite with a mass fraction of 80%;

[0033] Step 2: dissolving 2 g of the ethyl cellulose in 30 g of the ethyl acetate, adding the aqueous solution of sodium sulfite at 4° C., and stirring at a stirring speed of 1800 r / min for 25 min to obtain a single emulsion;

[0034] Step 3, immediately adding the aqueous solution of polyethylene glycol to the single emulsion, and stirring at a stirring speed of 1500 r / min for 20 min to obtain a double emulsion;

[0035] Step 4: After the double emulsion is allowed to stand for 2 hours in a vacuum environment, it is filtered under reduced pressure, and the obtained solid is washed with water and dried at 50° C. to obtain the sustained-release chlorine-removing microcapsules.

[0036] As a preferred embodiment, the molecular weight of polyethylene glycol is 4000.

[0037] Example 2

[0038] This embodiment provides a method for preparing sustained-release chlorine-removing microcapsules.

[0039] Step 1, providing an aqueous solution of sodium sulfite, ethyl cellulose, ethyl acetate, and an aqueous solution of polyethylene glycol;

[0040] The preparation of the aqueous solution of sodium sulfite is as follows: 75 g of sodium sulfite is dissolved in 100 g of water to obtain an aqueous solution of sodium sulfite with a mass fraction of 80%;

[0041] Step 2: dissolving 2 g of the ethyl cellulose in 30 g of the ethyl acetate, adding the aqueous solution of sodium sulfite at 6° C., and stirring at a stirring speed of 1800 r / min for 25 min to obtain a single emulsion;

[0042] Step 3, immediately adding the aqueous solution of polyethylene glycol to the single emulsion, and stirring at a stirring speed of 1500 r / min for 20 min to obtain a double emulsion;

[0043] Step 4: After the double emulsion is allowed to stand for 3 hours under a vacuum environment, it is filtered under reduced pressure, and the obtained solid is washed with water and dried at 40° C. to obtain the sustained-release chlorine-removing microcapsules.

[0044] Comparative test:

[0045] The residual chlorine removal performance of the slow-release chlorine removal microcapsules described in Example 1 and the commercially available sodium sulfite powder were tested respectively, and the test conditions are shown in the following table:

[0046]

[0047] Test results such as Figure 1 As shown in the test results, the sustained-release chlorine-removing microcapsules described in Example 1 are significantly better than the commercially available sodium sulfite powder.

[0048] In summary, the present invention adopts non-toxic and inexpensive water-insoluble ethyl cellulose as the main capsule wall material of the microcapsule, and adds ethyl acetate which is partially soluble in water to adjust the oil-water interface mass transfer of the emulsion. This combination not only improves the stability of the emulsion, but also is more conducive to the controlled sustained release of sodium sulfite as the capsule core, thereby prolonging the dechlorination effect, ensuring the continuous stability in the water treatment process, and also improving the utilization rate of sodium sulfite and the dechlorination efficiency.

[0049] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing sustained-release chlorine-removing microcapsules, characterized in that the steps include: Step 1, providing an aqueous solution of sodium sulfite, ethyl cellulose, ethyl acetate, and an aqueous solution of polyethylene glycol; Step 2, dissolving the ethyl cellulose in the ethyl acetate, adding the aqueous solution of sodium sulfite at 4° C.-6° C., and stirring to obtain a single emulsion; Step 3, immediately adding the aqueous solution of polyethylene glycol into the single emulsion and stirring to obtain a double emulsion; Step 4: After the double emulsion is allowed to stand in a vacuum environment, it is filtered under reduced pressure, and the obtained solid is washed with water and dried in sequence to obtain the slow-release chlorine-removing microcapsules.

2. The method for preparing a sustained-release chlorine-removing microcapsule according to claim 1, characterized in that: In the step 1, the mass fraction of the aqueous solution of sodium sulfite is 75%-80%; The mass fraction of the polyethylene glycol aqueous solution is 0.9%-1%.

3. The method for preparing a sustained-release chlorine-removing microcapsule according to claim 1, characterized in that: In the step 2, the mass ratio of the ethyl cellulose to the ethyl acetate is 1:(10-20).

4. The method for preparing a sustained-release chlorine-removing microcapsule according to claim 1, characterized in that: The stirring conditions in step 2 include: a stirring speed of 1700 r / min-1800 r / min, and a stirring time of 20 min-25 min; The stirring conditions in step three include: a stirring speed of 1500 r / min-1600 r / min, and a stirring time of 20 min-25 min.

5. The method for preparing a sustained-release chlorine-removing microcapsule according to claim 1, characterized in that: The standing time in step 4 is 2h-3h, and the drying temperature is 40°C-60°C.

6. The method for preparing a sustained-release chlorine-removing microcapsule according to claim 1, characterized in that: The molecular weight of the solute polyethylene glycol in the aqueous solution of polyethylene glycol is 3600-4400.

7. A sustained-release chlorine-removing microcapsule prepared by the method for preparing the sustained-release chlorine-removing microcapsule as claimed in any one of claims 1 to 6.

8. Use of the slow-release chlorine-removing microcapsule as claimed in claim 7 in purifying water resources.

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