Magnetic Prussian blue humus soil and preparation method and application method thereof

Abstract

The present invention relates to the field of environmental protection, and specifically to a magnetic Prussian blue humus soil, and a preparation method and application method thereof. The technical key points are as follows: The magnetic Prussian blue humus soil composite material is composed of humus soil, an iron source, and a Prussian blue nanomaterial. The present invention uses alkaline leaching and calcination to harmlessly treat and modify stale garbage humus soil, then uses a co-precipitation method to impart magnetic properties to the stale garbage humus soil. Finally, Prussian blue nanoparticles are in situ grown on the surface of the magnetic humus soil to further optimize its adsorption capacity for radioactive elements. Magnetic separation technology is used to effectively achieve efficient enrichment and recovery of the radioactive elements cesium and strontium in water, reducing the generation of secondary pollution. At the same time, the adsorbent realizes the resource utilization of stale garbage, which is beneficial to the protection of the ecological environment and the recycling of water resources.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, and in particular to a magnetic Prussian blue humus soil and a preparation method and an application method thereof. Background Art

[0002] Adsorption is an attractive option for purifying and removing radioactive contamination. It is simple, low-cost, and produces no hazardous byproducts. High adsorption efficiency and selectivity can be achieved by selecting appropriate adsorbent materials and adjusting different adsorption conditions. Commonly used adsorbents include natural clay minerals, activated carbon, and inorganic ion exchangers. Prussian blue, an adsorbent with high efficiency for removing cesium and strontium, is widely used in environmental pollution control due to its resistance to interference from other ions, high safety, and low cost. However, its large-scale use in engineering projects is limited by issues such as easy agglomeration and difficulty in solid-liquid separation, which remains an urgent issue. Summary of the Invention

[0003] The purpose of the present invention is to provide a magnetic Prussian blue humus soil. In view of the characteristics of Prussian blue that is easy to agglomerate in engineering applications and difficult to separate the solid and liquid after adsorption, the present invention realizes the resource utilization of humus soil in landfills. The present invention uses calcined stale garbage humus soil as a carrier of nano Prussian blue, introduces ferroferric oxide nanoparticles, and constructs a magnetic adsorbent. The above problems can be solved by magnetic separation technology, that is, the separation and treatment efficiency are simultaneously improved, and the purpose of energy saving and environmental protection is achieved.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions:

[0005] The invention provides a magnetic Prussian blue humus soil composite material, which is composited by modified humus soil, an iron source and a Prussian blue nanomaterial; the modified humus soil is obtained by modifying stale garbage.

[0006] The principle of this invention is to harmlessly treat and modify aged garbage humus soil through alkaline leaching and calcination, then impart magnetic properties to the soil through co-precipitation. Finally, Prussian blue nanoparticles are in situ grown on the surface of the magnetic humus soil to further optimize its adsorption capacity for radioactive elements. Magnetic separation technology effectively enriches and recovers radioactive elements such as cesium and strontium in water, reducing secondary pollution. The adsorbent also realizes resourceful utilization of aged garbage, contributing to ecological protection and water recycling.

[0007] Furthermore, the modified humus soil is obtained by modifying stale garbage with an alkaline solution.

[0008] Furthermore, the iron source is a mixture of a divalent iron salt and a trivalent iron salt.

[0009] Furthermore, the iron source is ferrous chloride and ferric chloride.

[0010] The second object of the present invention is to provide a method for preparing a magnetic Prussian blue humus soil composite material, which has the same technical effect.

[0011] The preparation method of the magnetic Prussian blue humus soil composite material provided by the present invention comprises the following steps:

[0012] S1. Screening the stale garbage to obtain stale garbage humus soil;

[0013] S2, placing the old garbage humus soil in an alkaline solution, stirring and soaking it, filtering and washing it until it is neutral, and calcining it to obtain modified humus soil;

[0014] S3, dissolving the modified humus soil, divalent iron salt, and trivalent iron salt in water and then adding the solution dropwise to the precipitant in reverse order to obtain magnetic humus soil;

[0015] S4. Growing Prussian blue nanoparticles on the surface of the magnetic humus soil multiple times to obtain the magnetic Prussian blue humus soil.

[0016] Furthermore, the screening method is to manually remove obvious impurities from the stale garbage and sieve it more than three times using a 200-mesh sieve.

[0017] Furthermore, the alkaline solution is a potassium hydroxide aqueous solution, and the mass ratio of potassium hydroxide to water is (2~2.5):8.

[0018] Furthermore, the mass ratio of stale garbage humus soil, potassium hydroxide and water is 1:(2~2.5):8.

[0019] Furthermore, in step S2, the stirring time is 1 to 3 hours, the stirring rate is 150 to 300 r / min, and the soaking time is 8 to 12 hours.

[0020] Furthermore, the calcination conditions in step S2 are keeping at 600°C for 8 hours and a heating rate of 10°C.

[0021] Furthermore, the specific operation steps of step S3 are:

[0022] S301, dissolve the divalent iron salt and the trivalent iron salt in water and stir evenly to obtain Fe 3+ / Fe 2+ mixed liquid;

[0023] S302, adding the modified humus soil to the Fe 3+ / Fe 2+ The mixed solution was stirred to obtain a suspension;

[0024] S303, adding the suspension dropwise into a precipitant and letting it stand, washing the precipitate with the aid of a magnet to obtain magnetic humus soil.

[0025] Furthermore, the molar ratio of the divalent iron salt to the trivalent iron salt is 1:2.5; wherein, when the mass of the modified humus soil is 2 g, the volume of deionized water is preferably 50 ml, and the mass of the divalent iron salt is preferably 1.20 g.

[0026] Furthermore, in step S302 , the heating temperature is 35-60° C., the stirring time is 15-30 min, and the stirring speed is 300-400 r / min.

[0027] Furthermore, the specific operations of step S4 are:

[0028] S401, dissolving magnetic humus in water to obtain a suspension which is added dropwise to an acidic K4[Fe(CN)6] solution;

[0029] S402, prepare multiple systems of equimolar FeCl3 and K4[Fe(CN)6] solutions, and adjust the pH to 2-3 with hydrochloric acid;

[0030] S403, adding dropwise to step S401 in sequence under vigorous stirring;

[0031] S404. The material obtained in step S403 is repeatedly washed with deionized water by means of magnetic adsorption, and freeze-dried to obtain magnetic Prussian blue humus soil that grows Prussian blue multiple times, namely the magnetic Prussian blue humus soil composite material.

[0032] Furthermore, the solid-liquid ratio of the magnetic humus soil aqueous suspension is 1:(20~25).

[0033] Furthermore, the stirring time in step S403 is 20-40 min, and the stirring rate is 200-300 r / min.

[0034] Furthermore, the washing method in step S404 is specifically washing with deionized water 3 to 5 times by magnetic adsorption, and freeze-drying at -60°C for 8 to 12 hours.

[0035] Furthermore, the volume of each solution in step S402 is preferably 100 ml.

[0036] Furthermore, the precipitant is ammonia water with a mass fraction of 7.69-8.7% and a volume of preferably 35 ml.

[0037] The third object of the present invention is to provide an application method of magnetic Prussian blue humus soil, which has the same technical effect.

[0038] The above technical objectives of the present invention are achieved by the following technical solutions:

[0039] The magnetic Prussian blue humus soil is placed in water to adsorb radioactive elements cesium and strontium, and after the adsorption is completed, the magnetic Prussian blue humus soil is recovered by a magnet.

[0040] Furthermore, 20 mg of magnetic Prussian blue humus was placed in a 50 mL solution with an initial cesium ion concentration of 10 mg / L. The reaction temperature was 298 K, the pH was 6, and the reaction was shaken at 180 rpm for 12 hours. The residual cesium ion concentration in the water was 0.306 mg / L, with an adsorption efficiency of 69.4%. Another 20 mg of magnetic Prussian blue humus was placed in a 50 mL solution with an initial strontium ion concentration of 5 mg / L. The reaction temperature was 298 K, the pH was 6, and the reaction was shaken at 180 rpm for 12 hours. The residual strontium ion concentration in the water was 0.459 mg / L, with an adsorption efficiency of 54.1%. The adsorbed magnetic Prussian blue humus can be effectively enriched and recovered using a magnet, achieving the goal of removing cesium and strontium ions from water.

[0041] In summary, the present invention has the following beneficial effects:

[0042] (1) The stale garbage humus soil has a loose "sponge-like" structure and contains a large number of active groups, which can strongly adsorb heavy metals. After modification with ferrite, the affinity for cesium ions is further improved. At the same time, it has a certain adsorption capacity for strontium ions. The experimental process is controllable, and the adsorption efficiency for cesium ions and strontium ions reaches 69.4% and 54.1%, respectively.

[0043] (2) After using magnetic Prussian blue stale garbage humus to remove cesium and strontium ions from water, magnetic separation technology can be used to achieve enrichment and recovery, thus avoiding the generation of secondary pollution;

[0044] (3) The present invention has a simple overall structure, occupies a small space, and the processing process is efficient and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the SEM image of magnetic Prussian blue humus soil;

[0046] Figure 2 is the XRD pattern of magnetic Prussian blue humus soil;

[0047] Figure 3 This is the FI-IR image of magnetic Prussian blue humus soil;

[0048] Figure 4 This is a diagram showing the effect of magnetic Prussian blue humus soil on adsorbing cesium ions under different pH conditions;

[0049] Figure 5This is a diagram showing the effect of magnetic Prussian blue humus soil adsorbing strontium ions under different temperature conditions. DETAILED DESCRIPTION

[0050] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, a magnetic Prussian blue humus soil and its preparation method and application method proposed in the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0051] Example 1

[0052] (1) Preparation of magnetic Prussian blue humus soil:

[0053] S1. Manually remove obvious impurities from the stale garbage and sieve it three times with a 200-mesh sieve to obtain stale garbage humus soil;

[0054] S2. Preparation of modified humus soil:

[0055] S201, 5 g of stale garbage humus soil, 11.28 g of potassium hydroxide, and 40 mL of deionized water were placed in a beaker, mechanically stirred for 3 h at a stirring rate of 150 r / min, and soaked for 12 h;

[0056] S202, washing the alkali-leached aged garbage humus soil with deionized water until the pH is neutral, and then calcining the soil at 600° C. in a muffle furnace for 8 h at a heating rate of 10° C. / min to obtain modified humus soil;

[0057] S3. Preparation of magnetic humus soil by co-precipitation method:

[0058] S301, dissolve 1.21g FeCl2·4H2O and 2.46g FeCl3·6H2O in 50 mL deionized water, stir at 45℃, and 3+ / Fe 2+ Mix the solution for 15 minutes;

[0059] S302, add 2g of modified humus soil to Fe 3+ / Fe 2+ The mixture was stirred for 15 min to obtain a uniformly mixed humus soil suspension;

[0060] S303, add the humus soil suspension dropwise to 35 mL of ammonia solution with a mass fraction of 8.7%, stir vigorously for 30 min, and let it stand for 12 h;

[0061] S304, separating the solid and liquid by means of a magnet, and washing the obtained soil with deionized water five times to obtain magnetic humus soil;

[0062] S4. Multiple growth of Prussian blue nanoparticles on the surface of magnetic humus soil:

[0063] S401, dissolve 0.64 g of K4[Fe(CN)6]·3H2O in 100 mL of deionized water and adjust the pH to 2 with hydrochloric acid;

[0064] S402. Under vigorous stirring (300 r / min), add 50 mL of the magnetic humus soil aqueous suspension (wherein the mass of the magnetic humus soil is 2.2 g) dropwise to the above acidic K4[Fe(CN)6] solution. After the addition is complete, continue stirring for 30 min.

[0065] S403, weigh two portions of 0.64g K4[Fe(CN)6]·3H2O and 0.41g FeCl3·6H2O, dissolve them in 100mL deionized water and adjust the pH to 2 with hydrochloric acid. Add FeCl3 and K4[Fe(CN)6] alternately in this order dropwise to the above-mentioned magnetic Prussian blue humus soil aqueous solution under vigorous stirring. Stir for 30min after each solution addition.

[0066] S404. The prepared material is repeatedly washed three times with deionized water by means of magnetic adsorption, and freeze-dried for 12 hours to obtain magnetic Prussian blue humus soil that grows Prussian blue multiple times.

[0067] The SEM, XRD and FI-IR patterns of the magnetic Prussian blue humus obtained in this example are shown in Figures 1 and 2. Figure 1 、 Figure 2 、 Figure 3 shown.

[0068] Water treatment using magnetic Prussian blue humus:

[0069] (1) 20 mg of the magnetic Prussian blue humus prepared in Example 1 was placed in a 50 mL solution with an initial cesium ion concentration of 10 mg / L. The reaction temperature was 298 K and the pH was 6. The solution was placed in a shaker at 180 r / min and reacted for 12 h. The removal rate of cesium ions in the test water was 69.4%. The adsorbed magnetic Prussian blue humus could be recovered using a magnet. Figure 4 The figure shows the effect of magnetic Prussian blue humus on the adsorption of cesium ions under different pH conditions, which shows that the adsorbent has a higher cesium ion adsorption efficiency at higher pH values. When pH=8, the adsorption value reaches a maximum of 50.23 mg / g.

[0070] (2) 20 mg of the magnetic Prussian blue humus prepared in Example 1 was placed in a 50 mL solution with an initial strontium ion concentration of 10 mg / L. The reaction temperature was 298 K and the pH was 6. The solution was placed in a shaker at 180 r / min for 12 h. The removal rate of strontium ions in the test water was 54.1%. The adsorbed magnetic Prussian blue humus could be recovered using a magnet. Figure 5 The figure shows the adsorption of strontium ions by magnetic Prussian blue humus at different temperatures. The adsorption efficiency increases with increasing temperature, reaching 48.38 mg / g at 328 K.

[0071] Example 2

[0072] (1) Preparation of magnetic Prussian blue humus soil:

[0073] S1. Manually remove obvious impurities from the stale garbage and sieve it three times with a 200-mesh sieve to obtain stale garbage humus soil;

[0074] S2. Preparation of modified humus soil:

[0075] S201, 3g of stale garbage humus soil, 6.77g of potassium hydroxide, and 24ml of deionized water were placed in a beaker, mechanically stirred for 2h at a stirring rate of 150r / min, and soaked for 10h;

[0076] S202, washing the alkali-leached aged garbage humus soil with deionized water until the pH is neutral, and then calcining the soil at 600° C. in a muffle furnace for 8 h at a heating rate of 10° C. / min to obtain modified humus soil;

[0077] S3. Preparation of magnetic humus soil by co-precipitation method:

[0078] S301, dissolve 1.21g FeCl2·4H2O and 2.46g FeCl3·6H2O in 50 mL deionized water, stir at 40℃, and 3+ / Fe 2+ Mixed solution 15min;

[0079] S302, add 2g of modified humus soil to Fe 3+ / Fe 2+ The mixture was stirred for 15 min to obtain a uniformly mixed humus soil suspension;

[0080] S303, add the humus soil suspension dropwise to 35 mL of ammonia solution with a mass fraction of 8%, stir vigorously for 30 minutes, and let it stand for 12 hours;

[0081] S304, separating the solid and liquid by means of a magnet, and washing the obtained soil with deionized water five times to obtain magnetic humus soil;

[0082] S4. Multiple growth of Prussian blue nanoparticles on the surface of magnetic humus soil:

[0083] S401, dissolve 0.85 g of K4[Fe(CN)6]·3H2O in 100 mL of deionized water and adjust the pH to 2 with hydrochloric acid;

[0084] S402. Under vigorous stirring (300 rpm), 50 mL of the magnetic humus aqueous suspension (the mass of the magnetic humus is the mass obtained in the first step of S4) is added dropwise to the acidic K4[Fe(CN)6] solution. After the addition is complete, stirring is continued for 30 minutes.

[0085] S403. Weigh two portions of 0.85 g K4[Fe(CN)6]·3H2O and 0.55 g FeCl3·6H2O, respectively, dissolve them in 100 mL of deionized water, and adjust the pH to 2 with hydrochloric acid. Add FeCl3 and K4[Fe(CN)6] alternately in this order dropwise to the magnetic Prussian blue humus aqueous solution under vigorous stirring. Stir for 30 minutes after each solution addition.

[0086] S404. The prepared material is repeatedly washed three times with deionized water by means of magnetic adsorption, and freeze-dried for 12 hours to obtain magnetic Prussian blue humus soil that grows Prussian blue multiple times.

[0087] The SEM, XRD and FI-IR patterns of the magnetic Prussian blue humus obtained in this example are shown in Figures 1 and 2. Figure 1 、 Figure 2 、 Figure 3 shown.

[0088] Water treatment using magnetic Prussian blue humus:

[0089] (1) Take 20 mg of the magnetic Prussian blue humus prepared in Example 2 and place it in a 50 mL solution with an initial cesium ion concentration of 10 mg / L. The reaction temperature is 298K and the pH is 6. Place it in a shaker at 180 r / min to react for 12 h. The removal rate of cesium ions in the test water is 68.52%. The adsorbed magnetic Prussian blue humus can be recovered using a magnet.

[0090] (2) Take 20 mg of the magnetic Prussian blue humus prepared in Example 2 and place it in a 50 mL solution with an initial strontium ion concentration of 10 mg / L. The reaction temperature is 298K and the pH is 6. Place it in a shaker at 180 r / min to react for 12 hours. The removal rate of strontium ions in the test water is 54.6%. The magnetic Prussian blue humus after adsorption can be recovered using a magnet.

[0091] Example 3

[0092] (1) Preparation of magnetic Prussian blue humus soil:

[0093] S1. Manually remove obvious impurities from the stale garbage and sieve it three times with a 200-mesh sieve to obtain stale garbage humus soil;

[0094] S2. Preparation of modified humus soil:

[0095] S201, 4 g of stale garbage humus soil, 8 g of potassium hydroxide, and 32 mL of deionized water were placed in a beaker, mechanically stirred for 1 h at a stirring rate of 150 r / min, and then soaked for 8 h;

[0096] S202, washing the alkali-leached aged garbage humus soil with deionized water until the pH is neutral, and then calcining the soil at 600° C. in a muffle furnace for 8 h at a heating rate of 10° C. / min to obtain modified humus soil;

[0097] S3. Preparation of magnetic humus soil by co-precipitation method:

[0098] S301, 1.21g FeCl2·4H2O, 2.46g FeCl3·6H2O were dissolved in 50mL deionized water, and FeCl2·4H2O was stirred at 45℃. 3+ / Fe 2+ Mixed solution 15min;

[0099] S302, add 2g of modified humus soil to Fe 3+ / Fe 2+ The mixture was stirred for 15 min to obtain a uniformly mixed humus soil suspension;

[0100] S303, add the humus soil suspension dropwise to 35 mL of ammonia solution with a mass fraction of 7.69%, stir vigorously for 30 min, and let it stand for 12 h;

[0101] S304, separating the solid and liquid by means of a magnet, and washing the obtained soil with deionized water five times to obtain magnetic humus soil;

[0102] S4. Multiple growth of Prussian blue nanoparticles on the surface of magnetic humus soil:

[0103] S401, dissolve 0.42 g of K4[Fe(CN)6]·3H2O in 100 mL of deionized water and adjust the pH to 2 with hydrochloric acid;

[0104] S402. Under vigorous stirring (300 r / min), add 50 mL of the magnetic humus soil aqueous suspension (wherein the mass of the magnetic humus soil is 2.2 g) dropwise to the above acidic K4[Fe(CN)6] solution. After the addition is complete, continue stirring for 30 min.

[0105] S403, weigh two portions of 0.42g K4[Fe(CN)6]·3H2O and 0.27g FeCl3·6H2O, dissolve them in 100mL deionized water and adjust the pH to 2 with hydrochloric acid. Add FeCl3 and K4[Fe(CN)6] alternately in this order dropwise to the above-mentioned magnetic Prussian blue humus soil aqueous solution under vigorous stirring. Stir for 30min after each solution addition.

[0106] S404. The prepared material is repeatedly washed three times with deionized water by means of magnetic adsorption, and freeze-dried for 12 hours to obtain magnetic Prussian blue humus soil that grows Prussian blue multiple times.

[0107] Water treatment using magnetic Prussian blue humus:

[0108] (1) Take 20 mg of the magnetic Prussian blue humus prepared in Example 3 and place it in a 50 mL solution with an initial cesium ion concentration of 10 mg / L. The reaction temperature is 298K and the pH is 6. Place it in a shaker at 180 r / min to react for 12 h. The removal rate of cesium ions in the test water is 67.1%. The adsorbed magnetic Prussian blue humus can be recovered using a magnet.

[0109] (2) Take 20 mg of the magnetic Prussian blue humus prepared in Example 3 and place it in a 50 mL solution with an initial strontium ion concentration of 10 mg / L. The reaction temperature is 298K and the pH is 6. Place it in a shaker at 180 r / min to react for 12 hours. The removal rate of strontium ions in the test water is 54.4%. The magnetic Prussian blue humus after adsorption can be recovered using a magnet.

[0110] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been presented as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A magnetic Prussian blue humus soil composite material, characterized in that: The magnetic Prussian blue humus composite material is composed of modified humus, an iron source and a Prussian blue nanomaterial. The modified humus is obtained by modifying old garbage with an alkaline solution; and the iron source is a mixture of divalent iron salt and trivalent iron salt.

2. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 1, wherein: The steps are as follows: S1. Screening the stale garbage to obtain stale garbage humus soil; S2, placing the old garbage humus soil in an alkaline solution, stirring and soaking it, filtering and washing it until it is neutral, and calcining it to obtain modified humus soil; S3, dissolving the modified humus soil, divalent iron salt, and trivalent iron salt in water and then adding the solution dropwise to the precipitant in reverse order to obtain magnetic humus soil; S4. Growing Prussian blue nanoparticles on the surface of the magnetic humus soil multiple times to obtain the magnetic Prussian blue humus soil.

3. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 2, characterized in that: The alkaline solution is a potassium hydroxide aqueous solution, and the mass ratio of potassium hydroxide to water is (2-2.5):

8.

4. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 2, characterized in that: The specific operation steps of step S3 are: S301, dissolve the divalent iron salt and the trivalent iron salt in water and stir evenly to obtain Fe 3+ / Fe 2+ mixed liquid; S302, adding the modified humus soil to the Fe 3+ / Fe 2+ The mixed solution was stirred to obtain a suspension; S303, adding the suspension dropwise into a precipitant and letting it stand, washing the precipitate with the aid of a magnet to obtain magnetic humus soil.

5. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 4, characterized in that: The molar ratio of the divalent iron salt to the trivalent iron salt is 1:2.

5.

6. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 2, characterized in that: The specific operations of step S4 are: S401, dissolving magnetic humus in water to obtain a suspension which is added dropwise to an acidic K4[Fe(CN)6] solution; S402, prepare multiple systems of equimolar FeCl3 and K4[Fe(CN)6] solutions, and adjust the pH to 2-3 with hydrochloric acid; S403, adding dropwise to step S401 in sequence under vigorous stirring; S404. The material obtained in step S403 is repeatedly washed with deionized water by means of magnetic adsorption, and freeze-dried to obtain magnetic Prussian blue humus soil that grows Prussian blue multiple times, namely the magnetic Prussian blue humus soil composite material.

7. The method for preparing the magnetic Prussian blue humus soil composite material according to claim 2, characterized in that: The precipitant is ammonia water with a mass fraction of 7.69-8.7%.

8. A method for using the magnetic Prussian blue humus soil according to claim 1, characterized in that: The magnetic Prussian blue humus soil is placed in water to adsorb radioactive elements cesium and strontium, and after the adsorption is completed, the magnetic Prussian blue humus soil is recovered by a magnet.

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