Preparation method and application of surface-functionalized cottonseed protein microspheres for highly selective removal of strontium ions

Abstract

The invention discloses a preparation method and application of surface-functionalized cottonseed protein microspheres for highly selective removal of strontium ions, which includes: dissolving cottonseed protein powder in sodium hydroxide solution and ultrasonically dispersing it, adding a surface modifier thereto, carrying out a heat preservation reaction, adding an excessive amount of ethanol solution and stirring, and then centrifuging to obtain purified cottonseed protein microspheres; mixing the purified cottonseed protein microspheres, plant tannins, and Prussian blue in deionized water, carrying out a constant-temperature oscillation reaction on a shaker, centrifuging to collect the product, and finally washing with ethanol and freeze-drying to obtain Prussian blue-functionalized cottonseed protein microspheres. Beneficial effects: Using plant tannins as a cross-linking agent to fix the active ingredient Prussian blue on the surface of cottonseed protein microspheres to increase the number of active sites, which is beneficial to the efficient and highly selective removal of strontium ions in the water environment and overcomes the problems of easy aggregation and difficult separation of Prussian blue; the materials used are environmentally friendly materials and will not cause secondary environmental pollution.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions. Background Art

[0002] The development and utilization of the nuclear industry has produced a large amount of radioactive wastewater. 90 Sr) is a common radionuclide with a half-life of 28.6 years. 90 Sr can accumulate through the food chain and enter the human body, causing internal radiation and pathological changes, which will seriously affect the ecological environment and human health. 90 Sr usually exists in water in the form of ions, so removing Sr from water 2+ It is an issue that needs to be addressed urgently.

[0003] At present, the removal of Sr from low-level strontium waste liquid discharged during nuclear industry production is widely studied at home and abroad. 2+ The main technical methods are: chemical precipitation, extraction and adsorption. The chemical precipitation method has large equipment, long processing cycle, low efficiency and easy to cause secondary pollution. The organic extractants used in the extraction method (such as crown ethers) are highly toxic, costly and easy to cause secondary pollution.

[0004] The adsorption method for treating low-level strontium waste has the advantages of high purification efficiency, low cost, simple operation, strong radiation resistance, and good resistance to Sr. 2+ Therefore, the preparation and research of adsorbent materials with good stability, excellent performance and low cost has always been one of the research focuses in the field of radioactive wastewater treatment. Adsorbent materials are divided into two types: organic adsorbents and inorganic adsorbents. Inorganic adsorbents have the advantages of large adsorption capacity, strong selectivity, good stability and easy handling. Common inorganic adsorbents include zeolite, carbon materials, metal sulfides, etc. Zeolite and metal sulfide adsorption of Sr 2+ When adsorbing, it is greatly affected by the pH value of the solution. Zeolite usually has good adsorption performance only in the neutral pH range. Metal sulfides are easily decomposed under strong acidic conditions, resulting in a decrease in performance. Summary of the invention

[0005] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0006] In order to achieve these purposes and other advantages according to the present invention, a method for preparing surface functionalized cottonseed protein microspheres for high selective removal of strontium ions is provided, comprising the following steps:

[0007] Step 1: Dissolve cottonseed protein powder in sodium hydroxide solution, then disperse it by ultrasonic treatment. Next, add a surface modifier thereto, and after maintaining the temperature for reaction, add an excessive amount of ethanol to the system and stir to form cottonseed protein microspheres. Centrifuge to remove other impurities, and obtain purified cottonseed protein microspheres by low-temperature drying;

[0008] Step 2: Mix purified cottonseed protein microspheres, vegetable tannin, and Prussian blue uniformly in deionized water according to a ratio, and then react at a constant temperature on a shaker to fix Prussian blue on the surface of cottonseed protein microspheres by the complexing action of vegetable tannin. After the reaction is complete, centrifuge to collect the product, and finally wash it with an ethanol solution and freeze-dry to obtain cottonseed protein microspheres functionalized with Prussian blue on the surface.

[0009] Preferably, in Step 1, the concentration of the sodium hydroxide solution is 5-10 wt%, and the mass ratio of cottonseed protein powder, surface modifier, and sodium hydroxide is 90-96:1-2:1-10.

[0010] Preferably, in Step 1, the surface modifier is one or more of polyethylene glycol, methoxypolyethylene glycol, sorbitan monooleate, and sodium octadecyl sulfonate.

[0011] Preferably, in Step 1, the ultrasonic dispersion time is 20-60 min, the temperature for maintaining the reaction is 20-35 °C, and the reaction time is 4-8 h.

[0012] Preferably, in Step 1, the centrifugation rate is 6000-8000 rpm, the centrifugation time is 0.5-1 h, the low-temperature drying temperature is 5-10 °C, the drying time is 8-12 h, the stirring speed is 100-200 rpm, and the stirring time is 1-2 h.

[0013] Preferably, in Step 2, the mass ratio of purified cottonseed protein microspheres, vegetable tannin, Prussian blue, and deionized water is 60-65:5-10:15-25:5-10.

[0014] Preferably, in Step 2, the vegetable tannin is one of myrica tannin, apple tannin, grape tannin, and green tea tannin.

[0015] Preferably, in Step 2, the temperature for constant-temperature oscillation is 30-40 °C, the oscillation time is 2.5-5 h, the freeze-drying temperature is -5-5 °C, and the drying time is 1-2 d.

[0016] Preferably, in Step 2, the centrifugation rate is 8000-12000 rpm, and the centrifugation time is 0.5-1 h.

[0017] The present invention also provides an application of the surface-functionalized cottonseed protein microspheres, and the surface-functionalized cottonseed protein microspheres are used for adsorbing low-level radioactive waste liquid containing strontium in nuclear industry production.

[0018] The present invention has at least the following beneficial effects: By using vegetable tannin as a crosslinking agent and utilizing the complexing effect of vegetable tannin, the active ingredient Prussian blue is fixed on the surface of cottonseed protein microspheres to increase the number of active sites, which is conducive to the efficient and highly selective removal of strontium ions in the water environment and overcomes the problems of easy aggregation and difficult separation of Prussian blue. At the same time, the cottonseed protein, vegetable tannin, and Prussian blue used are all low in price, wide in source, and environmentally friendly materials, and will not cause secondary environmental pollution.

[0019] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Removal efficiency graph of Sr for Examples 1-3 and Comparative Examples 1-3 of the present invention 2+ of. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0022] Example 1

[0023] A preparation method of surface-functionalized cottonseed protein microspheres for highly selective removal of strontium ions, comprising:

[0024] Step 1: Dissolve 900 g of cottonseed protein powder in 1 L of 8 wt% sodium hydroxide solution, then ultrasonically disperse for 30 min, add 10 g of methoxypolyethylene glycol thereto, keep the temperature at 25 °C for reaction for 4 h, add excessive ethanol to the system and stir at a speed of 150 rpm for 1 h to form cottonseed protein microspheres, centrifuge at a speed of 6500 rpm for 0.5 h to remove other impurities, and then dry at a low temperature of 10 °C for 12 h to obtain purified cottonseed protein microspheres;

[0025] Step 2: Mix 600 g of purified cottonseed protein microspheres, 50 g of apple tannin, 200 g of Prussian blue, and 100 g of deionized water evenly in proportion, then oscillate at a constant temperature of 35 °C on a shaker for 3 h, transfer to a centrifuge after the reaction is completed and centrifuge at 10000 rpm for 1 h, wash with ethanol after centrifugation is completed, and then freeze-dry at -5 °C for 1 d to obtain surface Prussian blue-functionalized cottonseed protein microspheres.

[0026] Example 2

[0027] A preparation method of surface-functionalized cottonseed protein microspheres for highly selective removal of strontium ions, comprising:

[0028] Step 1: Dissolve 950 g of cottonseed protein powder in 1 L of 10 wt% sodium hydroxide solution, then ultrasonically disperse for 30 min. Then add 10 g of methoxypolyethylene glycol thereto, keep the temperature at 25 °C and react for 4 h. After that, add excessive ethanol to the system and stir at a speed of 150 rpm for 1 h to form cottonseed protein microspheres. Centrifuge at 6500 rpm for 0.5 h to remove other impurities, and then dry at a low temperature of 10 °C for 12 h to obtain purified cottonseed protein microspheres;

[0029] Step 2: Mix 650 g of purified cottonseed protein microspheres, 80 g of myrica tannin, 220 g of prussian blue and 100 g of deionized water evenly according to the proportion. Then keep the temperature constant at 35 °C and oscillate on a shaker for 3 h. After the reaction is completed, transfer it to a centrifuge and centrifuge at 10000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 °C for 1 d to obtain cottonseed protein microspheres functionalized with prussian blue on the surface.

[0030] Example 3

[0031] A preparation method of surface-functionalized cottonseed protein microspheres for highly selective removal of strontium ions, comprising:

[0032] Step 1: Dissolve 900 g of cottonseed protein powder in 1 L of 10 wt% sodium hydroxide solution, then ultrasonically disperse for 30 min. Then add 10 g of methoxypolyethylene glycol thereto, keep the temperature at 25 °C and react for 4 h. After that, add excessive ethanol to the system and stir at a speed of 150 rpm for 1 h to form cottonseed protein microspheres. Centrifuge at 6500 rpm for 0.5 h to remove other impurities, and then dry at a low temperature of 10 °C for 12 h to obtain purified cottonseed protein microspheres;

[0033] Step 2: Mix 650 g of purified cottonseed protein microspheres, 100 g of grape tannin, 250 g of prussian blue and 100 g of deionized water evenly according to the proportion. Then keep the temperature constant at 35 °C and oscillate on a shaker for 3 h. After the reaction is completed, transfer it to a centrifuge and centrifuge at 10000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 °C for 1 d to obtain cottonseed protein microspheres functionalized with prussian blue on the surface.

[0034] Comparative Example 1

[0035] The difference between this comparative example and Example 1 is that in Step 2, 600 g of purified cottonseed protein microspheres, 200 g of prussian blue and 150 g of deionized water are mixed evenly according to the proportion. Then keep the temperature constant at 35 °C and oscillate on a shaker for 3 h. After the reaction is completed, transfer it to a centrifuge and centrifuge at 10000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 °C for 1 d to obtain cottonseed protein microspheres with only a small amount of prussian blue adhered thereto.

[0036] Comparative Example 2

[0037] The difference between this comparative example and Example 1 is that in Step 2, 600 g of purified cottonseed protein microspheres, 50 g of apple tannin, and 300 g of deionized water are mixed evenly in proportion, and then shaken on a shaker at a constant temperature of 35 °C for 3 h. After the reaction, it is transferred to a centrifuge and centrifuged at 10,000 rpm for 1 h. After centrifugation, it is washed with ethanol and then freeze-dried at -5 °C for 1 d to obtain cottonseed protein microspheres loaded with apple tannin.

[0038] Comparative Example 3

[0039] Only Step 1 of Example 1 is carried out in this comparative example to obtain purified cottonseed protein microspheres.

[0040] The strontium adsorption tests are carried out using Examples 1 to 3 and Comparative Examples 1 to 3. The method is as follows: A solution with a Sr 2+ concentration of 10 mg / L is prepared as a simulated strontium-containing waste liquid. 1 g of microglobulin is added to the strontium-containing waste liquid, and adsorption is carried out at a constant temperature of 25 °C for 2.5 h. After filtration, it is left standing, and the concentration of the remaining strontium ions in the supernatant is measured by ICP-MS to calculate the adsorption rate. The results are shown in Table 1 and Figure 1 .

[0041] Table 1

[0042] <![CDATA[Remaining Sr 2+ Concentration (mg / L)]]> Adsorption rate Example 1 0.226 97.74％ Example 2 0.227 97.73％ Example 3 0.224 97.76％ Comparative Example 1 1.545 84.55％ Comparative Example 2 2.354 76.46％ Comparative Example 3 2.012 79.88％

[0043] As can be seen from Table 1 and Figure 1 it can be seen that in Examples 1 to 3 of the present invention, plant tannins are used as cross-linking agents to fix the active ingredient Prussian blue on the surface of cottonseed protein microspheres to increase the number of active sites, which can effectively improve the adsorption rate of cottonseed protein microspheres for Sr 2+ in wastewater; in Comparative Example 3, ordinary cottonseed protein is used for adsorption, and the adsorption rate is low. In Comparative Example 1, plant tannins are not used as cross-linking agents, resulting in only a small amount of Prussian blue adhering to cottonseed microglobulin, and the adsorption rate increases less. In Comparative Example 2, Prussian blue is not added, and only apple tannin cross-linking agent is added, which will instead affect the adsorption force of cottonseed protein, resulting in a lower adsorption rate than that of ordinary cottonseed protein.

[0044] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples described herein.

Claims

1. A method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions, characterized in that: The following steps are involved: Step 1, dissolving cottonseed protein powder in a sodium hydroxide solution, then ultrasonically dispersing, adding a surface modifier thereto, keeping warm for reaction, adding excess ethanol to the system and stirring to form cottonseed protein microspheres, centrifuging to remove impurities, and low-temperature drying to obtain purified cottonseed protein microspheres; Step 2: Evenly mix the purified cottonseed protein microspheres, plant tannins, and Prussian blue in deionized water in proportion, and then react on a shaker at a constant temperature. After the reaction is complete, the product is collected by centrifugation, and finally washed with an ethanol solution and freeze-dried to obtain cottonseed protein microspheres functionalized with Prussian blue on the surface.

2. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 1, the concentration of the sodium hydroxide solution is 5-10wt%, and the mass ratio of the cottonseed protein powder, the surface modifier, and the sodium hydroxide is 90-96:1-2:1-10.

3. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 1, the surface modifier is one or more of polyethylene glycol, methoxy polyethylene glycol, sorbitan monooleate, and sodium octadecyl sulfonate.

4. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 1, ultrasonic dispersion is performed for 20 to 60 minutes, the heat preservation reaction temperature is 20 to 35° C., the reaction time is 4 to 8 hours, the stirring speed is 100 to 200 rpm, and the stirring time is 1 to 2 hours.

5. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 1, the centrifugal speed is 6000-8000 rpm, the centrifugation time is 0.5-1 h, the low-temperature drying temperature is 5-10° C., and the drying time is 8-12 h.

6. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 2, the mass ratio of the purified cottonseed protein microspheres, the plant tannins, the Prussian blue and the deionized water is 60-65:5-10:15-25:5-10.

7. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 2, the plant tannin is one of bayberry tannin, apple tannin, grape tannin and green tea tannin.

8. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 2, the constant temperature oscillation temperature is 30 to 40° C., the oscillation time is 2.5 to 5 hours, the freeze drying temperature is -5 to 5° C., and the freeze drying is 1 to 2 days.

9. The method for preparing surface functionalized cottonseed protein microspheres for highly selective removal of strontium ions according to claim 1, characterized in that: In the step 2, the centrifugal speed is 8000-12000 rpm, and the centrifugal time is 0.5-1 h.

10. An application of surface functionalized cottonseed protein microspheres prepared by the preparation method according to any one of claims 1 to 9, characterized in that: Surface functionalized cottonseed protein microspheres are used to adsorb low-level radioactive waste liquid containing strontium in nuclear industry production.

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