Preparation method and application of surface-functionalized cottonseed protein microspheres for high-selectivity removal of strontium ions

Abstract

The invention discloses a preparation method and application of surface-functionalized cottonseed protein microspheres for high-selectivity removal of strontium ions, and the preparation method comprises the following steps: dissolving cottonseed protein powder in a sodium hydroxide solution, carrying out ultrasonic dispersion, adding a surface modifier into the solution, carrying out a heat preservation reaction, adding an excessive ethanol solution, stirring, centrifuging, washing, and drying to obtain the surface-functionalized cottonseed protein microspheres. Obtaining purified cottonseed protein microspheres; and mixing the purified cottonseed protein microspheres, vegetable tannin and Prussian blue in deionized water, carrying out a constant-temperature oscillation reaction on a shaking table, centrifugally collecting a product, and finally washing with ethanol and freeze-drying to obtain the Prussian blue functionalized cottonseed protein microspheres. The preparation method has the beneficial effects that the plant tannin is used as a cross-linking agent to fix the active ingredient Prussian blue on the surfaces of the cottonseed protein microspheres, so that the number of active sites is increased, the strontium ions in a water environment can be efficiently and selectively removed, and the problems that the Prussian blue is easy to gather and difficult to separate are solved; and the used materials are environment-friendly materials, so that secondary pollution to the environment is avoided.

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, 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 other impurities, and low-temperature drying to obtain purified cottonseed protein microspheres;

[0008] Step 2: Evenly mix the purified cottonseed protein microspheres, plant tannins, and Prussian blue in deionized water in proportion, and then oscillate on a shaker at a constant temperature to react, thereby utilizing the chelation effect of the plant tannins to fix the Prussian blue on the surface of the cottonseed protein microspheres. 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.

[0009] Preferably, in 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.

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

[0011] Preferably, in the step 1, the ultrasonic dispersion time is 20 to 60 minutes, the insulation reaction temperature is 20 to 35° C., and the reaction time is 4 to 8 hours.

[0012] Preferably, in 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., 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 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.

[0014] Preferably, in step 2, the plant tannin is one of bayberry tannin, apple tannin, grape tannin and green tea tannin.

[0015] Preferably, in 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 drying time is 1 to 2 days.

[0016] Preferably, in step 2, the centrifugal speed is 8000-12000 rpm, and the centrifugal time is 0.5-1 h.

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

[0018] The present invention includes at least the following beneficial effects: using plant tannin as a cross-linking agent, utilizing the complexing effect of the plant tannin, fixing the active ingredient Prussian blue on the surface of cottonseed protein microspheres, so as 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 overcoming the problem that Prussian blue is easy to aggregate and difficult to separate; at the same time, the cottonseed protein, plant tannin and Prussian blue used are all low-priced, widely available, and are environmentally friendly materials, and will not cause secondary environmental pollution.

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

[0020] Figure 1 The Sr of Examples 1-3 and Comparative Examples 1-3 of the present invention is 2+ Removal efficiency diagram. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0022] Example 1

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

[0024] Step 1, dissolving 900g cottonseed protein powder in 1L 8wt% sodium hydroxide solution, then ultrasonically dispersing for 30min, adding 10g methoxy polyethylene glycol thereto, keeping warm at 25°C for 4h, adding excess ethanol to the system and stirring at 150rpm for 1h to form cottonseed protein microspheres, centrifuging at 6500rpm for 0.5h to remove other impurities, and then low-temperature drying at 10°C for 12h to obtain purified cottonseed protein microspheres;

[0025] Step 2: Mix 600 g purified cottonseed protein microspheres, 50 g apple tannin, 200 g Prussian blue and 100 g deionized water in proportion, and then oscillate on a shaker at 35 ° C for 3 h. After the reaction is completed, transfer to a centrifuge and centrifuge at 10,000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 ° C for 1 day to obtain cottonseed protein microspheres functionalized with Prussian blue on the surface.

[0026] Example 2

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

[0028] Step 1, dissolving 950g cottonseed protein powder in 1L 10wt% sodium hydroxide solution, then ultrasonically dispersing for 30min, adding 10g methoxy polyethylene glycol thereto, keeping the reaction at 25°C for 4h, adding excess ethanol to the system and stirring at 150rpm for 1h to form cottonseed protein microspheres, centrifuging at 6500rpm for 0.5h to remove other impurities, and then low-temperature drying at 10°C for 12h to obtain purified cottonseed protein microspheres;

[0029] Step 2: Mix 650 g purified cottonseed protein microspheres, 80 g bayberry tannin, 220 g Prussian blue and 100 g deionized water in proportion, and then oscillate on a shaker at 35 ° C for 3 h. After the reaction is completed, transfer to a centrifuge and centrifuge at 10,000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 ° C for 1 day to obtain cottonseed protein microspheres functionalized with Prussian blue on the surface.

[0030] Example 3

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

[0032] Step 1, dissolving 900g cottonseed protein powder in 1L 10wt% sodium hydroxide solution, then ultrasonically dispersing for 30min, adding 10g methoxy polyethylene glycol thereto, keeping warm for 4h at 25°C, adding excess ethanol to the system and stirring at 150rpm for 1h to form cottonseed protein microspheres, centrifuging at 6500rpm for 0.5h to remove other impurities, and then low-temperature drying at 10°C for 12h to obtain purified cottonseed protein microspheres;

[0033] Step 2: Mix 650 g purified cottonseed protein microspheres, 100 g grape tannin, 250 g Prussian blue and 100 g deionized water in proportion, and then oscillate on a shaker at 35 ° C for 3 h. After the reaction is completed, transfer to a centrifuge and centrifuge at 10,000 rpm for 1 h. After centrifugation, wash with ethanol, and then freeze-dry at -5 ° C for 1 day 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 in proportion, and then oscillated on a shaker at a constant temperature of 35° C. for 3 h. After the reaction is completed, the microspheres are transferred to a centrifuge and centrifuged at 10,000 rpm for 1 h. After the centrifugation is completed, the microspheres are washed with ethanol, and then freeze-dried at -5° C. for 1 day to obtain cottonseed protein microspheres with only a small amount of Prussian blue attached.

[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 oscillated on a shaker at a constant temperature of 35° C. for 3 h. After the reaction is completed, the microspheres are transferred to a centrifuge and centrifuged at 10,000 rpm for 1 h. After the centrifugation is completed, the microspheres are washed with ethanol, and then freeze-dried at -5° C. for 1 day to obtain cottonseed protein microspheres loaded with apple tannin.

[0038] Comparative Example 3

[0039] In this comparative example, only step 1 of Example 1 was performed to obtain purified cottonseed protein microspheres.

[0040] The strontium adsorption test was carried out using Examples 1 to 3 and Comparative Examples 1 to 3. The method is as follows: prepare Sr 2+ A solution with a concentration of 10 mg / L was used as a simulated strontium-containing waste liquid. 1 g of microglobulin was added to the strontium-containing waste liquid and adsorbed at a constant temperature of 25°C for 2.5 hours. After filtration, the solution was allowed to stand. The concentration of the remaining strontium ions in the supernatant was determined by ICP-MS and the adsorption rate was calculated. The results are shown in Table 1 and Figure 1 .

[0041] Table 1

[0042] <![CDATA[Residual 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] From Table 1 and Figure 1 It can be seen that Examples 1 to 3 of the present invention use plant tannin 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 can effectively improve the cottonseed protein microspheres for Sr in wastewater. 2+ The adsorption rate of Comparative Example 3 was lower than that of ordinary cottonseed protein, and the adsorption rate was lower than that of ordinary cottonseed protein, as a result, only a small amount of Prussian blue adhered to the cottonseed microglobulin, and the adsorption rate was slightly improved. In Comparative Example 2, only apple tannin cross-linking agent was added, but Prussian blue was not added, which would affect the adsorption capacity of cottonseed protein and result 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 implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and 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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