A long-term repair agent for organic contaminated sites and preparation method thereof

Abstract

The present invention relates to the technical field of chemical remediation of organic contaminated sites, and in particular to a long-acting remediator for organic contaminated sites and a preparation method thereof, including S1, calcium chloride is dissolved and then added dropwise to a nano core material; S2 uses surfactant self-assembly to confine the calcium peroxide-nano core material complex in a polymer cavity; S3, by vacuum impregnation, nanosheets are infiltrated into the pores of mesoporous polymer core-shell microspheres; S4 uses composite mesoporous polymer core-shell microspheres as capsule cores, and calcium alginate / chitosan cortex is coated on the capsule core surface, and dried naturally. The remediator prepared by the present invention has strong adsorption, and can adsorb organic pollutants in soil, and utilizes the strong oxidizing property of calcium peroxide to oxidize and degrade it, while the nano core material has high activity, and can provide sufficient active sites for the oxidation of calcium peroxide, improve the oxidation effect, and enhance the oxidation effect, so that the degradation of organic pollutants can be accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of chemical remediation of organic contaminated sites, in particular to a long-acting remediation agent for organic contaminated sites and a preparation method thereof. Background Art

[0002] With the acceleration of China's urbanization process, a large number of petroleum, chemical, coking and other enterprises have been relocated from urban areas, forming a large number of industrial legacy organic pollution sites. Due to the high toxicity and easy diffusion of organic pollutants, these organic pollution sites seriously threaten the surrounding environmental conditions, the health of residents and the reuse of land, and it is urgent to take rapid and efficient measures to control them. Among the methods for removing organic pollutants from soil, in-situ chemical oxidation is widely used because of its relatively low remediation cost, rapid remediation effect and simple operation. However, the degradation efficiency of traditional soil remediation agents for organic pollutants is not ideal, and they have a great impact on soil nutrients and physical and chemical properties, which can easily cause secondary pollution.

[0003] Calcium peroxide is an environmentally friendly material with both nutrient-releasing and oxidizing properties. It reacts with water in the soil environment to release molecular oxygen and hydrogen peroxide. Hydrogen peroxide can be catalyzed by iron minerals in the soil to generate hydroxyl radicals, thereby degrading organic pollutants. Therefore, compared with traditional soil remediation agents, calcium peroxide has a wider pH range, is non-toxic itself and its reduced products, and has a short half-life. It is an oxidant that is very suitable for chemical remediation of organic contaminated soils.

[0004] For example, Chinese patent CN115433584B discloses a calcium peroxide-sodium persulfate synergistic in-situ remediation method for organic composite contaminated sites, wherein a variety of carboxylic acids, alcohols, and ester organic substances are oxidized to inorganic states through a slow-release composite oxidant, a soil wetting agent promotes the penetration and circulation of a first-order remediation agent in the soil, and a chelating agent microsphere penetrates into the soil to slowly release a metal chelating agent to form a stable complex with a variety of harmful metal ions. The in-situ remediation method achieves long-term remediation of soil in organic composite contaminated sites through the remediation of remediation agents with different component contents in two stages, and has a good removal effect on polycyclic aromatic hydrocarbons and heavy metal ions; however, the calcium peroxide loaded in the slow-release composite oxidant is easily lost from the soil during the slow release process, resulting in a low utilization rate. At the same time, after the metal chelating agent released from the chelating agent microsphere forms a complex with the harmful metal ions, it remains in the soil and is not easy to remove, and when the structure of some complexes is unstable, metal ions will desorb, which is easy to cause secondary pollution. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a long-term remediation agent for organic contaminated sites and a preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a long-term repair agent for organic contaminated sites comprises the following steps:

[0008] S1: dissolving calcium chloride, adding it dropwise to the nano core material, stirring it fully, washing it by centrifugation, drying it, grinding it and sieving it to obtain a calcium peroxide-nano core material composite;

[0009] S2 uses surfactant self-assembly combined with low-concentration hydrothermal method to confine the calcium peroxide-nanocore material complex in the polymer cavity to obtain mesoporous polymer core-shell microspheres;

[0010] S3 infiltrates the nanosheets into the pores of the mesoporous polymer core-shell microspheres by vacuum impregnation to obtain composite mesoporous polymer core-shell microspheres;

[0011] S4 uses composite mesoporous polymer core-shell microspheres as the capsule core, and utilizes layer-by-layer self-assembly to coat the surface of the capsule core with a calcium alginate / chitosan cortex, which is then dried naturally.

[0012] As a further preferred embodiment of the present invention, S1 comprises the following steps:

[0013] Calcium chloride is dissolved in a mixed solvent consisting of double distilled water and ammonia water, and then hydrogen peroxide is added dropwise and stirred for 30-70 minutes, and sodium hydroxide solution is added dropwise to adjust the pH to 10-11, and then the nano core material is added and fully stirred, and the mixture is placed at room temperature and stirred for 30-50 minutes. After being repeatedly washed with deionized water until neutral, the mixture is placed in a drying oven and dried, ground into powder, and sieved to obtain a calcium peroxide-nano core composite material with a particle size of 200-500 nm.

[0014] As a further preferred embodiment of the present invention, the ratio of calcium chloride, mixed solvent and hydrogen peroxide is (2-6) g: (30-80) mL: (15-30) mL;

[0015] The mixed solvent is composed of double distilled water and ammonia water in a volume ratio of (2-3):1;

[0016] The hydrogen peroxide has a concentration of 30-35wt%;

[0017] The stirring speed is 200-500r / min.

[0018] As a further preferred embodiment of the present invention, the nano core material is prepared by the following method:

[0019] 1) Take deionized water, heat to boiling, then add chloroauric acid aqueous solution and sodium citrate aqueous solution in sequence, stir and reflux at 500-800 r / min for 30-50 min, let stand and cool to room temperature, adjust the pH value to 8.5-9.0, add 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 3-7 h, centrifuge and dry to obtain modified nano-gold cores;

[0020] 2) Add sodium borohydride solution to the cobalt chloride solution, stir thoroughly, then add ferric chloride solution to form a mixed solution, then add sodium molybdate solution and modified nano-gold cores, let stand for 6-10 hours to form a hydrogel, wash repeatedly with ultrapure water, and set aside;

[0021] 3) After the above-mentioned spare product is centrifuged at 5000-8000r / min for 5-10min, the supernatant is removed, and the remaining solid is quickly frozen with liquid nitrogen to form a wet gel, which is freeze-dried for 24-36h to obtain molybdenum-doped aerogel, and then the selenium powder and the molybdenum-doped aerogel are placed in the upstream and downstream of a tubular furnace respectively according to a mass ratio of 1: (20-30), and selenized at 400-420°C for 3-6h in an argon atmosphere, and naturally cooled to room temperature to obtain the nano core material.

[0022] As a further preferred embodiment of the present invention, the volume ratio of the ionized water, the chloroauric acid aqueous solution, the sodium citrate aqueous solution, and the 3-mercaptopropyltrimethoxysilane aqueous solution is (200-300): (25-32): (12-15): (12-15);

[0023] The aqueous solution of chloroauric acid has a concentration of 2.5-2.8 mmol / L;

[0024] The sodium citrate aqueous solution has a concentration of 10-13 mg / mL;

[0025] The 3-mercaptopropyltrimethoxysilane aqueous solution has a concentration of 1.0-1.3 mmol / L;

[0026] The ratio of the cobalt chloride solution, sodium borohydride solution, ferric chloride solution, sodium molybdate solution, and modified nano-gold core is (5-10) mL: (15-20) mL: (5-10) mL: (3-6) mL: (1-2) g;

[0027] The cobalt chloride solution has a concentration of 0.05-0.07 mol / L;

[0028] The sodium borohydride solution has a concentration of 0.1-0.3 mol / L;

[0029] The ferric chloride solution has a concentration of 0.05-0.07 mol / L;

[0030] The sodium molybdate solution has a concentration of 0.05-0.08 mol / L.

[0031] As a further preferred embodiment of the present invention, S2 comprises the following steps:

[0032] Weigh 6-10g of phenol, 20-28mL of 37wt% formaldehyde solution and 150-230mL of 0.1-0.2mol / L sodium hydroxide solution, react at 45-47°C for 30-50min, add the obtained product and 9-13g of triblock polymer F127 into 150-200mL of deionized water, stir and react at 66-68°C for 2-5h, then add 500-600mL of deionized water and 2-5g of calcium peroxide-nanocore composite material, continue stirring for 16-20h, cool to room temperature, place the product in a hydrothermal kettle, hydrothermally react in an oven at 130-135°C for 24-30h, and after the reaction is completed, fully dry at 150-160°C.

[0033] As a further preferred embodiment of the present invention, S3 comprises the following steps:

[0034] 1) Dissolve 1.2-1.8g of stannous chloride in 20-35mL of deionized water and stir well at room temperature, then add 0.12-0.16g of cupric chloride and stir for 10-20min, then add 1.8-2.1g of hexadecyltrimethylammonium bromide and continue stirring for 30-50min to obtain solution A, and weigh 0.7-0.8g of sodium hydroxide and dissolve it in 20-30mL of deionized water, stir well to obtain solution B for later use;

[0035] 2) Solution A and solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor for reaction for 24-30 hours. The obtained product is repeatedly washed with deionized water and ethanol, dried, and then annealed in a muffle furnace for 3-6 hours to obtain a flower-like nanomaterial;

[0036] 3) Disperse the flower-like nanomaterials in an ethanol solution, stir and disperse thoroughly to obtain a dispersion, then place the mesoporous polymer core-shell microspheres in a vacuum impregnation tank at a solid-liquid ratio of 1: (20-30) g / mL, evacuate to 10-50 Pa, maintain for 10-15 minutes, inject the dispersion, and maintain under ultrasonic action for 20-30 minutes. After the treatment is completed, slowly release the pressure to normal pressure, repeatedly wash the product with deionized water, and then dry it.

[0037] As a further preferred embodiment of the present invention, the reaction in the high pressure reactor is carried out at a temperature of 130-135°C;

[0038] The annealing temperature is 500-530°C;

[0039] The dispersion has a solid content of 2-5wt%;

[0040] The power of the ultrasonic effect is 100-150W.

[0041] As a further preferred embodiment of the present invention, S4 comprises the following steps:

[0042] 5-10g of composite mesoporous polymer core-shell microspheres are dispersed in 200-500mL of deionized water, 400-900mL of 1-3wt% dodecyltrimethylammonium bromide solution is added dropwise, magnetic stirring is performed for 1-3h, centrifugal washing is performed for 3-5 times, and then dispersed in deionized water to form a 1-3mg / mL dispersion, and then 30-40mL of the dispersion is added dropwise to 50-70mL of 4-6mg / mL sodium alginate solution, magnetic stirring is performed for 30-50min, centrifugal washing is performed for 3-5 times, and then dispersed in 50-70mL of 4-6mg / mL chitosan solution, the chitosan solution contains 1-2% acetic acid by volume and 2-3% calcium chloride by mass, magnetic stirring is performed for 30-50min, and then the precipitate is repeatedly washed with 1-2% acetic acid by volume and deionized water, and the precipitate is naturally dried.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The repair agent prepared by the present invention has strong adsorption capacity, can adsorb organic pollutants in the soil, and utilize the strong oxidizing property of calcium peroxide to oxidize and degrade them. At the same time, the nano core material has high activity, can provide sufficient active sites for the oxidation of calcium peroxide, improve the oxidation effect, and enhance the oxidation effect, thereby accelerating the degradation of organic pollutants. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The present invention provides a method for preparing a long-term repair agent for organic contaminated sites, comprising the following steps:

[0047] S1: dissolving calcium chloride, adding it dropwise to the nano core material, stirring it fully, washing it by centrifugation, drying it, grinding it and sieving it to obtain a calcium peroxide-nano core material composite;

[0048] The steps include:

[0049] Dissolve calcium chloride in a mixed solvent consisting of deionized water and ammonia water, then drop hydrogen peroxide and stir for 30-70 minutes, drop sodium hydroxide solution to adjust the pH to 10-11, then add the nano core material and stir thoroughly, and continue stirring for 30-50 minutes at room temperature, wash repeatedly with deionized water until neutral, dry in a drying oven, grind into powder, and sieve to obtain a calcium peroxide-nano core composite material with a particle size of 200-500 nm;

[0050] Furthermore, the ratio of calcium chloride, mixed solvent, and hydrogen peroxide is (2-6) g: (30-80) mL: (15-30) mL;

[0051] The mixed solvent is composed of double distilled water and ammonia water in a volume ratio of (2-3):1;

[0052] Hydrogen peroxide, concentration 30-35wt%;

[0053] Stirring, the speed is 200-500r / min;

[0054] Furthermore, the nano core material is prepared as follows:

[0055] 1) Take deionized water, heat to boiling, then add chloroauric acid aqueous solution and sodium citrate aqueous solution in sequence, stir and reflux at 500-800 r / min for 30-50 min, let stand and cool to room temperature, adjust the pH value to 8.5-9.0, add 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 3-7 h, centrifuge and dry to obtain modified nano-gold cores;

[0056] 2) Add sodium borohydride solution to the cobalt chloride solution, stir thoroughly, then add ferric chloride solution to form a mixed solution, then add sodium molybdate solution and modified nano-gold cores, let stand for 6-10 hours to form a hydrogel, wash repeatedly with ultrapure water, and set aside;

[0057] 3) After the above-mentioned spare product is centrifuged at 5000-8000r / min for 5-10min, the supernatant is removed, and the remaining solid is quickly frozen with liquid nitrogen to form a wet gel, and freeze-dried for 24-36h to obtain a molybdenum-doped aerogel, and then the selenium powder and the molybdenum-doped aerogel are placed in the upstream and downstream of a tubular furnace respectively according to a mass ratio of 1: (20-30), and selenized at 400-420°C for 3-6h in an argon atmosphere, and naturally cooled to room temperature to obtain a nano core material;

[0058] Further, the volume ratio of ionized water, chloroauric acid aqueous solution, sodium citrate aqueous solution, and 3-mercaptopropyltrimethoxysilane aqueous solution is (200-300):(25-32):(12-15):(12-15);

[0059] Chloroauric acid aqueous solution, concentration 2.5-2.8mmol / L;

[0060] Sodium citrate aqueous solution, concentration 10-13 mg / mL;

[0061] 3-Mercaptopropyltrimethoxysilane aqueous solution, concentration 1.0-1.3mmol / L;

[0062] The ratio of cobalt chloride solution, sodium borohydride solution, ferric chloride solution, sodium molybdate solution, and modified nano-gold core is (5-10) mL: (15-20) mL: (5-10) mL: (3-6) mL: (1-2) g;

[0063] Cobalt chloride solution, concentration 0.05-0.07 mol / L;

[0064] Sodium borohydride solution, concentration 0.1-0.3 mol / L;

[0065] Ferric chloride solution, concentration 0.05-0.07 mol / L;

[0066] Sodium molybdate solution, concentration 0.05-0.08 mol / L;

[0067] S2 uses surfactant self-assembly combined with low-concentration hydrothermal method to confine the calcium peroxide-nanocore material complex in the polymer cavity to obtain mesoporous polymer core-shell microspheres;

[0068] The method comprises the following steps: weighing 6-10g of phenol, 20-28mL of a 37wt% formaldehyde solution and 150-230mL of a 0.1-0.2mol / L sodium hydroxide solution, reacting at 45-47°C for 30-50min, adding the obtained product and 9-13g of a triblock polymer F127 into 150-200mL of deionized water, stirring and reacting at 66-68°C for 2-5h, then adding 500-600mL of deionized water and 2-5g of a calcium peroxide-nanocore composite material, continuing to stir for 16-20h, standing and cooling to room temperature, placing the product in a hydrothermal kettle, hydrothermally reacting in an oven at 130-135°C for 24-30h, and fully drying at 150-160°C after the reaction is completed;

[0069] S3 infiltrates the nanosheets into the pores of the mesoporous polymer core-shell microspheres by vacuum impregnation to obtain composite mesoporous polymer core-shell microspheres;

[0070] The steps include:

[0071] 1) Dissolve 1.2-1.8g of stannous chloride in 20-35mL of deionized water and stir well at room temperature, then add 0.12-0.16g of cupric chloride and stir for 10-20min, then add 1.8-2.1g of hexadecyltrimethylammonium bromide and continue stirring for 30-50min to obtain solution A, and weigh 0.7-0.8g of sodium hydroxide and dissolve it in 20-30mL of deionized water, stir well to obtain solution B for later use;

[0072] 2) Solution A and solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor for reaction for 24-30 hours. The obtained product is repeatedly washed with deionized water and ethanol, dried, and then annealed in a muffle furnace for 3-6 hours to obtain a flower-like nanomaterial;

[0073] 3) Disperse the flower-like nanomaterials in an ethanol solution, stir and disperse thoroughly to obtain a dispersion, then place the mesoporous polymer core-shell microspheres in a vacuum impregnation tank at a solid-liquid ratio of 1: (20-30) g / mL, evacuate to 10-50 Pa, maintain for 10-15 minutes, inject the dispersion, and maintain under ultrasonic action for 20-30 minutes. After the treatment is completed, slowly release the pressure to normal pressure, repeatedly wash the product with deionized water, and then dry it;

[0074] Further, the reaction is carried out in a high pressure reactor at a temperature of 130-135°C;

[0075] Annealing, temperature is 500-530℃;

[0076] Dispersion, solid content 2-5wt%;

[0077] Ultrasonic action, power is 100-150W;

[0078] S4 uses composite mesoporous polymer core-shell microspheres as the capsule core, and uses layer-by-layer self-assembly to coat the surface of the capsule core with a calcium alginate / chitosan skin layer, which is then dried naturally;

[0079] The steps include:

[0080] 5-10g of composite mesoporous polymer core-shell microspheres are dispersed in 200-500mL of deionized water, 400-900mL of 1-3wt% dodecyltrimethylammonium bromide solution is added dropwise, magnetic stirring is performed for 1-3h, centrifugal washing is performed for 3-5 times, and then dispersed in deionized water to form a 1-3mg / mL dispersion, and then 30-40mL of the dispersion is added dropwise to 50-70mL of 4-6mg / mL sodium alginate solution, magnetic stirring is performed for 30-50min, centrifugal washing is performed for 3-5 times, and then dispersed in 50-70mL of 4-6mg / mL chitosan solution, the chitosan solution contains 1-2% acetic acid by volume and 2-3% calcium chloride by mass, magnetic stirring is performed for 30-50min, and then the precipitate is repeatedly washed with 1-2% acetic acid by volume and deionized water, and the precipitate is naturally dried.

[0081] The invention uses chloroauric acid as a gold source and 3-mercaptopropyltrimethoxysilane as a modifier, utilizes the strong coordination effect between gold core and mercapto group, obtains modified nano gold core modified by 3-mercaptopropyltrimethoxysilane through ligand exchange, and then uses cobalt chloride, sodium borohydride, ferric chloride, sodium molybdate and the like as raw materials to prepare a three-dimensional nanowire cross-linked network aerogel through a directional gelation method, and introduces the modified nano gold core into the cross-linked network of the aerogel to obtain molybdenum-doped aerogel, and after selenization treatment under an argon atmosphere, the surface roughness of the aerogel is increased, which is conducive to the modified nano gold core to form a firm adhesion in the aerogel, thereby obtaining a nano core material; then Calcium chloride is then used as a calcium source, and the nano core material has a multi-void three-dimensional structure as a carrier, and the calcium peroxide generated by the reaction is loaded in the carrier, thereby forming a calcium peroxide-nano core composite material; then, through low-concentration hydrothermal self-assembly, the triblock polymer F127 and the low-order phenolic resin prepolymer form spherical composite single micelles through hydrogen bonding, and because under high-temperature hydrothermal conditions, the 3-mercaptopropyltrimethoxysilane on the surface of the modified nano gold core is hydrolyzed to produce Si-OH, the formed Si-OH has strong hydrogen bonds with the phenolic resin and block polymer in the spherical composite single micelle, thereby promoting the composite single micelle in the calcium peroxide-nano core composite material. Surface aggregation and self-assembly, thereby forming a mesoporous polymer core-shell microsphere with a core-shell structure having a calcium peroxide-nano core composite material as the core and a mesoporous polymer as the shell. The formed polymer shell of the mesoporous structure can limit the solidification of the core to prevent it from being lost. At the same time, in order to further improve the limiting effect, the present invention also prepares a flower-shaped nanomaterial composed of nanosheets by a hydrothermal method, and by a vacuum impregnation method, the flower-shaped nanomaterial can be embedded into the mesopores under the assistance of ultrasound to obtain a composite mesoporous polymer core-shell microsphere. The embedded flower-shaped nanomaterial increases the degree of tortuosity of the mesoporous structure, thereby extending the movement path of the core, thereby The loss of the core is further suppressed, and the movement path of organic pollutants is increased, so that the organic pollutants adsorbed into the pores will not be desorbed, thus avoiding the generation of secondary pollution; finally, dodecyltrimethylammonium bromide is used to change the surface potential of the composite mesoporous polymer core-shell microspheres, and sodium alginate and chitosan are used as the cortical materials. The layer-by-layer self-assembly principle is utilized to form a coating layer on the surface of the composite mesoporous polymer core-shell microspheres, thereby obtaining a repair agent with a microcapsule structure; by forming a microcapsule structure, a sustained release effect of the core can be achieved, thereby increasing the utilization rate of calcium peroxide in the core and achieving the purpose of long-term degradation of organic pollutants in the soil.

[0082] At the same time, at the end of the preparation method, the precipitate is naturally dried and then fully shaken. This is because during the entire process, part of the calcium peroxide reacts with water to generate calcium hydroxide, and the generated calcium hydroxide covers the surface of the calcium peroxide, thereby preventing the calcium peroxide from further reacting with water. As a result, most of the calcium peroxide is retained during the entire reaction process, and then the water is removed by fully drying and shaking, so that the calcium hydroxide covering the surface of the calcium peroxide can be peeled off, thereby exposing the calcium peroxide, which will not affect the strong oxidizing property of the calcium peroxide.

[0083] The repair agent prepared by the present invention comprises a composite mesoporous polymer core-shell microsphere with a porous structure, a capillary effect, and a strong adsorption capacity, and can adsorb organic pollutants in the soil into the pores. The strong oxidizing property of calcium peroxide can be used to oxidize and degrade the organic pollutants in the soil. At the same time, the modified nano-gold core and aerogel of the nano-core material are highly active and can provide sufficient active sites for the oxidation of calcium peroxide, thereby improving the oxidation effect and enhancing the oxidation effect, thereby accelerating the degradation of organic pollutants.

[0084] Example 1

[0085] A method for preparing a long-term repair agent for organic contaminated sites comprises the following steps:

[0086] S1: 2 g of calcium chloride is dissolved in 30 mL of a mixed solvent consisting of deionized water and ammonia water in a volume ratio of 2:1, and then 15 mL of 30 wt% hydrogen peroxide is added dropwise, stirred at 200 r / min for 30 min, and sodium hydroxide solution is added dropwise to adjust the pH to 10, and then the nano-core material is added and stirred thoroughly, and stirred for 30 min at room temperature, and after repeated washing with deionized water until neutral, it is placed in a drying oven to dry, ground into powder, and sieved to obtain a calcium peroxide-nano-core composite material with a particle size of 200 nm;

[0087] S2 weighed 6g of phenol, 20mL of 37wt% formaldehyde solution and 150mL of 0.1mol / L sodium hydroxide solution, reacted at 45°C for 30min, added the obtained product and 9g of triblock polymer F127 into 150mL of deionized water, stirred and reacted at 66°C for 2h, then added 500mL of deionized water and 2g of calcium peroxide-nanocore composite material, continued stirring for 16h, cooled to room temperature, placed the product in a hydrothermal kettle, and hydrothermally reacted in an oven at 130°C for 24h. After the reaction was completed, it was fully dried at 150°C to obtain mesoporous polymer core-shell microspheres;

[0088] S3-1) Dissolve 1.2 g of stannous chloride in 20 mL of deionized water and stir well at room temperature, then add 0.12 g of cupric chloride and stir for 10 min, then add 1.8 g of hexadecyltrimethylammonium bromide and continue stirring for 30 min to obtain solution A, and weigh 0.7 g of sodium hydroxide and dissolve it in 20 mL of deionized water, stir well to obtain solution B for later use;

[0089] S3-2) Solution A and Solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor, reacted at 130°C for 24 hours, and the obtained product is repeatedly washed with deionized water and ethanol and dried, and then placed in a muffle furnace and annealed at 500°C for 3 hours to obtain a flower-like nanomaterial;

[0090] S3-3) Dispersing the flower-like nanomaterial in an ethanol solution, stirring and dispersing the solution sufficiently to obtain a dispersion having a solid content of 2 wt%, and then placing the mesoporous polymer core-shell microspheres in a vacuum impregnation tank at a solid-liquid ratio of 1:20 g / mL, evacuating the solution to 10 Pa, maintaining the solution for 10 min, injecting the dispersion, and maintaining the solution under 100 W ultrasonic action for 20 min. After the treatment is completed, the pressure is slowly released to normal pressure, and the product is repeatedly washed with deionized water and dried to obtain composite mesoporous polymer core-shell microspheres;

[0091] S4: 5 g of composite mesoporous polymer core-shell microspheres were dispersed in 200 mL of deionized water, and 400 mL of 1 wt% dodecyltrimethylammonium bromide solution was added dropwise. After magnetic stirring for 1 hour, the mixture was centrifuged and washed three times, and then dispersed in deionized water to form a 1 mg / mL dispersion. Subsequently, 30 mL of the dispersion was added dropwise into 50 mL of 4 mg / mL sodium alginate solution, magnetic stirring was performed for 30 minutes, and the mixture was centrifuged and washed three times, and then dispersed in 50 mL of 4 mg / mL chitosan solution. The chitosan solution contained 1% acetic acid by volume and 2% calcium chloride by mass. After magnetic stirring for 30 minutes, the mixture was repeatedly washed with 1% acetic acid by volume and deionized water. The precipitate was naturally dried and then oscillated at 500 r / min for 20 minutes.

[0092] The preparation method of the nano core material is as follows:

[0093] 1) Measure 200 mL of deionized water, heat to boiling, then add 25 mL of 2.5 mmol / L chloroauric acid aqueous solution and 12 mL of 10 mg / mL sodium citrate aqueous solution, stir and reflux at 500 r / min for 30 min, let stand and cool to room temperature, adjust the pH value to 8.5, add 12 mL of 1.0 mmol / L 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 3 h, centrifuge and dry to obtain modified nano-gold cores;

[0094] 2) Add 15 mL of 0.1 mol / L sodium borohydride solution to 5 mL of 0.05 mol / L cobalt chloride solution, stir thoroughly, add 5 mL of 0.05 mol / L ferric chloride solution to form a mixed solution, add 3 mL of 0.05 mol / L sodium molybdate solution and 1 g of modified nano-gold core, let stand for 6 hours to form a hydrogel, wash repeatedly with ultrapure water, and set aside;

[0095] 3) After centrifuging the above-mentioned spare product at 5000r / min for 5min, the supernatant was removed, and the remaining solid was quickly frozen with liquid nitrogen to form a wet gel, which was freeze-dried for 24h to obtain molybdenum-doped aerogel. Then, selenium powder and molybdenum-doped aerogel were placed upstream and downstream of a tubular furnace respectively in a mass ratio of 1:20, and selenized at 400°C for 3h in an argon atmosphere, and naturally cooled to room temperature to obtain a nano core material.

[0096] Example 2

[0097] A method for preparing a long-term repair agent for organic contaminated sites comprises the following steps:

[0098] S1: 4 g of calcium chloride is dissolved in 50 mL of a mixed solvent consisting of double distilled water and ammonia water in a volume ratio of 2.5:1, and then 25 mL of 32 wt% hydrogen peroxide is added dropwise, stirred at 300 r / min for 50 min, and sodium hydroxide solution is added dropwise to adjust the pH to 10.5, and then the nano-core material is added and stirred thoroughly, and stirred for 40 min at room temperature, and after repeated washing with deionized water until neutral, it is placed in a drying oven to dry, ground into powder, and sieved to obtain a calcium peroxide-nano-core composite material with a particle size of 300 nm;

[0099] S2 weighed 8g of phenol, 25mL of 37wt% formaldehyde solution and 200mL of 0.2mol / L sodium hydroxide solution, reacted at 46°C for 40min, added the obtained product and 10g of triblock polymer F127 into 180mL of deionized water, stirred and reacted at 67°C for 3h, then added 550mL of deionized water and 3g of calcium peroxide-nanocore composite material, continued stirring for 18h, cooled to room temperature, placed the product in a hydrothermal kettle, and hydrothermally reacted in an oven at 132°C for 28h. After the reaction was completed, it was fully dried at 155°C to obtain mesoporous polymer core-shell microspheres;

[0100] S3-1) Dissolve 1.5 g of stannous chloride in 30 mL of deionized water and stir well at room temperature, then add 0.15 g of cupric chloride, stir for 15 min, then add 2 g of hexadecyltrimethylammonium bromide and continue stirring for 40 min to obtain solution A, and weigh 0.8 g of sodium hydroxide and dissolve it in 26 mL of deionized water, stir well to obtain solution B for later use;

[0101] S3-2) Solution A and Solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor, reacted at 132°C for 26 hours, and the obtained product is repeatedly washed with deionized water and ethanol and dried, and then placed in a muffle furnace and annealed at 520°C for 5 hours to obtain a flower-like nanomaterial;

[0102] S3-3) The flower-like nanomaterial is dispersed in an ethanol solution, and after being fully stirred and dispersed, a dispersion having a solid content of 3 wt% is obtained. Then, the mesoporous polymer core-shell microspheres are placed in a vacuum impregnation tank at a solid-liquid ratio of 1:25 g / mL, and the vacuum is evacuated to 30 Pa. After maintaining for 12 minutes, the dispersion is injected and maintained under 120 W ultrasonic action for 25 minutes. After the treatment is completed, the pressure is slowly released to normal pressure, and the product is repeatedly washed with deionized water and dried to obtain composite mesoporous polymer core-shell microspheres;

[0103] S4: 7g of composite mesoporous polymer core-shell microspheres were dispersed in 400mL of deionized water, and 700mL of 2wt% dodecyltrimethylammonium bromide solution was added dropwise. After magnetic stirring for 2h, the mixture was centrifuged and washed 4 times, and then dispersed in deionized water to form a 2mg / mL dispersion. Subsequently, 35mL of the dispersion was added dropwise into 60mL of 5mg / mL sodium alginate solution, magnetic stirring for 40min, and centrifuged and washed 4 times, and then dispersed in 60mL of 5mg / mL chitosan solution. The chitosan solution contained 1.5% acetic acid by volume and 2.5% calcium chloride by mass. After magnetic stirring for 40min, the mixture was repeatedly washed with 1.5% acetic acid by volume and deionized water. The precipitate was dried naturally and then oscillated at 700r / min for 25min.

[0104] The preparation method of the nano core material is as follows:

[0105] 1) Measure 260 mL of deionized water, heat to boiling, then add 30 mL of 2.6 mmol / L chloroauric acid aqueous solution and 13 mL of 12 mg / mL sodium citrate aqueous solution, stir and reflux at 700 r / min for 40 min, let stand and cool to room temperature, adjust the pH value to 9.0, add 13 mL of 1.2 mmol / L 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 5 h, centrifuge and dry to obtain modified nano-gold cores;

[0106] 2) Add 18 mL of 0.2 mol / L sodium borohydride solution to 7 mL of 0.06 mol / L cobalt chloride solution, stir thoroughly, add 7 mL of 0.06 mol / L ferric chloride solution, add 5 mL of 0.06 mol / L sodium molybdate solution and 1.5 g of modified nano-gold core to form a mixed solution, let stand for 8 h to form a hydrogel, wash repeatedly with ultrapure water, and set aside;

[0107] 3) After centrifuging the above-mentioned spare product at 6000r / min for 8min, the supernatant was removed, and the remaining solid was quickly frozen with liquid nitrogen to form a wet gel, which was freeze-dried for 32h to obtain molybdenum-doped aerogel. Then, selenium powder and molybdenum-doped aerogel were placed in the upstream and downstream of a tubular furnace respectively in a mass ratio of 1:25, and selenized at 410°C for 5h in an argon atmosphere, and naturally cooled to room temperature to obtain a nano core material.

[0108] Example 3

[0109] A method for preparing a long-term repair agent for organic contaminated sites comprises the following steps:

[0110] S1: 6 g of calcium chloride is dissolved in 80 mL of a mixed solvent consisting of deionized water and ammonia water in a volume ratio of 3:1, and then 30 mL of 35 wt% hydrogen peroxide is added dropwise, stirred at 500 r / min for 70 min, and sodium hydroxide solution is added dropwise to adjust the pH to 11, and then the nano-core material is added and stirred thoroughly, and stirred for 50 min at room temperature, and after repeated washing with deionized water until neutral, it is placed in a drying oven to dry, ground into powder, and sieved to obtain a calcium peroxide-nano-core composite material with a particle size of 500 nm;

[0111] S2 weighed 10g of phenol, 28mL of 37wt% formaldehyde solution and 230mL of 0.2mol / L sodium hydroxide solution, reacted at 47°C for 50min, added the obtained product and 13g of triblock polymer F127 into 200mL of deionized water, stirred and reacted at 68°C for 5h, then added 600mL of deionized water and 5g of calcium peroxide-nanocore composite material, continued stirring for 20h, cooled to room temperature, placed the product in a hydrothermal kettle, and hydrothermally reacted in an oven at 135°C for 30h. After the reaction was completed, it was fully dried at 160°C to obtain mesoporous polymer core-shell microspheres;

[0112] S3-1) Dissolve 1.8 g of stannous chloride in 35 mL of deionized water and stir well at room temperature, then add 0.16 g of cupric chloride, stir for 20 min, then add 2.1 g of hexadecyltrimethylammonium bromide and continue stirring for 50 min to obtain solution A, and weigh 0.8 g of sodium hydroxide and dissolve it in 30 mL of deionized water, stir well to obtain solution B for later use;

[0113] S3-2) Solution A and Solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor, reacted at 135°C for 30 hours, and the obtained product is repeatedly washed with deionized water and ethanol and dried, and then placed in a muffle furnace and annealed at 530°C for 6 hours to obtain a flower-like nanomaterial;

[0114] S3-3) The flower-like nanomaterial is dispersed in an ethanol solution, and after being fully stirred and dispersed, a dispersion having a solid content of 5 wt% is obtained. Then, at a solid-liquid ratio of 1:30 g / mL, the mesoporous polymer core-shell microspheres are placed in a vacuum impregnation tank, and the vacuum is evacuated to 50 Pa. After maintaining for 15 minutes, the dispersion is injected and maintained under 150 W ultrasonic action for 30 minutes. After the treatment is completed, the pressure is slowly released to normal pressure, and the product is repeatedly washed with deionized water and dried to obtain composite mesoporous polymer core-shell microspheres;

[0115] S4: 10g of composite mesoporous polymer core-shell microspheres were dispersed in 500mL of deionized water, and 900mL of 3wt% dodecyltrimethylammonium bromide solution was added dropwise. After magnetic stirring for 3h, the mixture was centrifuged and washed 5 times, and then dispersed in deionized water to form a 3mg / mL dispersion. Subsequently, 40mL of the dispersion was added dropwise into 70mL of 6mg / mL sodium alginate solution, magnetic stirring for 50min, and centrifuged and washed 5 times, and then dispersed into 70mL of 6mg / mL chitosan solution. The chitosan solution contained 2% acetic acid by volume and 3% calcium chloride by mass. After magnetic stirring for 50min, the mixture was repeatedly washed with 2% acetic acid by volume and deionized water. The precipitate was dried naturally and then oscillated at 800r / min for 30min.

[0116] The preparation method of the nano core material is as follows:

[0117] 1) Measure 300 mL of deionized water, heat to boiling, then add 32 mL of 2.8 mmol / L chloroauric acid aqueous solution and 15 mL of 13 mg / mL sodium citrate aqueous solution, stir and reflux at 800 r / min for 50 min, let stand and cool to room temperature, adjust the pH value to 9.0, add 15 mL of 1.3 mmol / L 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 7 h, centrifuge and dry to obtain modified nano-gold cores;

[0118] 2) Add 20 mL of 0.3 mol / L sodium borohydride solution to 10 mL of 0.07 mol / L cobalt chloride solution, stir thoroughly, add 10 mL of 0.07 mol / L ferric chloride solution, add 6 mL of 0.08 mol / L sodium molybdate solution and 2 g of modified nano-gold core to form a mixed solution, let stand for 10 hours to form a hydrogel, wash repeatedly with ultrapure water, and set aside;

[0119] 3) After centrifuging the above-mentioned spare product at 8000r / min for 10min, the supernatant was removed, and the remaining solid was quickly frozen with liquid nitrogen to form a wet gel, which was freeze-dried for 36h to obtain molybdenum-doped aerogel. Then, selenium powder and molybdenum-doped aerogel were placed upstream and downstream of a tubular furnace respectively in a mass ratio of 1:30, and selenized at 420°C for 6h in an argon atmosphere, and naturally cooled to room temperature to obtain a nano core material.

[0120] Comparative Example 1: This comparative example is basically the same as Example 1, except that the nano core material in S1 is omitted.

[0121] Comparative Example 2: This comparative example is basically the same as Example 1, except that step 1) is omitted in the preparation of the nano core material.

[0122] Comparative Example 3: This comparative example is basically the same as Example 1, except that in the preparation of the nano core material, steps 2)-3) are omitted.

[0123] Comparative Example 4: This comparative example is substantially the same as Example 1, except that S2 is omitted.

[0124] Comparative Example 5: This comparative example is substantially the same as Example 1, except that S3 is omitted.

[0125] Comparative Example 6: This comparative example is substantially the same as Example 1, except that the oscillation process in S4 is omitted.

[0126] Test experiment:

[0127] The methods provided in Examples 1-3 and Comparative Examples 1-6 were respectively used to obtain repair agent samples; then 10 g of contaminated soil with a polycyclic aromatic hydrocarbon content of 50 mg / kg was weighed and placed in a 250 mL conical flask, 40 mL of deionized water was added to prepare a slurry soil mixed solution, and the soil liquid-solid mass ratio was 4:1, 0.4 g of the repair agent sample was added, and the mixture was stirred thoroughly and allowed to stand for 24 hours. The polycyclic aromatic hydrocarbons remaining in the soil were extracted by ultrasonic method, and the results were quantitatively detected and analyzed by liquid chromatography. The results are shown in Table 1.

[0128] Table 1

[0129]

[0130] It can be seen from Table 1 that the repair agent of the present invention can effectively oxidize and degrade the organic pollutants remaining in the soil to achieve soil repair.

[0131] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a long-term remediation agent for organic contaminated sites, characterized in that: The steps include: S1: dissolving calcium chloride, adding it dropwise to the nano core material, stirring it fully, washing it by centrifugation, drying it, grinding it and sieving it to obtain a calcium peroxide-nano core material composite; The nano core material is prepared by the following method: 1) Take deionized water, heat to boiling, then add chloroauric acid aqueous solution and sodium citrate aqueous solution in sequence, stir and reflux at 500-800 r / min for 30-50 min, let stand and cool to room temperature, adjust the pH value to 8.5-9.0, add 3-mercaptopropyltrimethoxysilane aqueous solution, continue stirring at room temperature for 3-7 h, centrifuge and dry to obtain modified nano-gold cores; 2) Add sodium borohydride solution to the cobalt chloride solution, stir thoroughly, then add ferric chloride solution to form a mixed solution, then add sodium molybdate solution and modified nano-gold cores, let stand for 6-10 hours to form a hydrogel, wash repeatedly with ultrapure water, and set aside; 3) After the standby product is centrifuged at 5000-8000 r / min for 5-10 min, the supernatant is removed, and the remaining solid is quickly frozen with liquid nitrogen to form a wet gel, which is freeze-dried for 24-36 h to obtain a molybdenum-doped aerogel, and then the selenium powder and the molybdenum-doped aerogel are placed in the upstream and downstream of a tubular furnace respectively in a mass ratio of 1:(20-30), and selenized at 400-420° C. for 3-6 h in an argon atmosphere, and naturally cooled to room temperature to obtain a nano core material; S2 uses surfactant self-assembly combined with low-concentration hydrothermal method to confine the calcium peroxide-nanocore material complex in the polymer cavity to obtain mesoporous polymer core-shell microspheres; S3 infiltrates the nanosheets into the pores of the mesoporous polymer core-shell microspheres by vacuum impregnation to obtain composite mesoporous polymer core-shell microspheres; The S3 comprises the following steps: 1) Dissolve 1.2-1.8g of stannous chloride in 20-35mL of deionized water and stir well at room temperature, then add 0.12-0.16g of cupric chloride and stir for 10-20min, then add 1.8-2.1g of hexadecyltrimethylammonium bromide and continue stirring for 30-50min to obtain solution A, and weigh 0.7-0.8g of sodium hydroxide and dissolve it in 20-30mL of deionized water, stir well to obtain solution B for later use; 2) Solution A and solution B are mixed and stirred thoroughly, and then transferred to a high-pressure reactor for reaction for 24-30 hours. The obtained product is repeatedly washed with deionized water and ethanol, dried, and then annealed in a muffle furnace for 3-6 hours to obtain a flower-like nanomaterial; 3) Disperse the flower-like nanomaterials in an ethanol solution, stir and disperse thoroughly to obtain a dispersion, then place the mesoporous polymer core-shell microspheres in a vacuum impregnation tank at a solid-liquid ratio of 1: (20-30) g / mL, evacuate to 10-50 Pa, maintain for 10-15 minutes, inject the dispersion, and maintain under ultrasonic action for 20-30 minutes. After the treatment is completed, slowly release the pressure to normal pressure, wash the product repeatedly with deionized water, and then dry it; S4 uses composite mesoporous polymer core-shell microspheres as the capsule core, and utilizes layer-by-layer self-assembly to coat the surface of the capsule core with a calcium alginate / chitosan cortex, which is then dried naturally.

2. The method for preparing a long-term repair agent for organic contaminated sites according to claim 1, characterized in that: The S1 comprises the following steps: Calcium chloride is dissolved in a mixed solvent consisting of double distilled water and ammonia water, and then hydrogen peroxide is added dropwise and stirred for 30-70 minutes, and sodium hydroxide solution is added dropwise to adjust the pH to 10-11, and then the nano core material is added and fully stirred, and the mixture is placed at room temperature and stirred for 30-50 minutes. After being repeatedly washed with deionized water until neutral, the mixture is placed in a drying oven and dried, ground into powder, and sieved to obtain a calcium peroxide-nano core composite material with a particle size of 200-500 nm.

3. The method for preparing a long-term repair agent for organic contaminated sites according to claim 2, characterized in that: The ratio of calcium chloride, mixed solvent and hydrogen peroxide is (2-6) g: (30-80) mL: (15-30) mL; The mixed solvent is composed of double distilled water and ammonia water in a volume ratio of (2-3):1; The hydrogen peroxide has a concentration of 30-35wt%; The stirring speed is 200-500r / min.

4. The method for preparing a long-term repair agent for organic contaminated sites according to claim 3, characterized in that: The volume ratio of the ionized water, the chloroauric acid aqueous solution, the sodium citrate aqueous solution, and the 3-mercaptopropyltrimethoxysilane aqueous solution is (200-300): (25-32): (12-15): (12-15); The aqueous solution of chloroauric acid has a concentration of 2.5-2.8 mmol / L; The sodium citrate aqueous solution has a concentration of 10-13 mg / mL; The 3-mercaptopropyltrimethoxysilane aqueous solution has a concentration of 1.0-1.3 mmol / L; The ratio of the cobalt chloride solution, sodium borohydride solution, ferric chloride solution, sodium molybdate solution, and modified nano-gold core is (5-10) mL: (15-20) mL: (5-10) mL: (3-6) mL: (1-2) g; The cobalt chloride solution has a concentration of 0.05-0.07 mol / L; The sodium borohydride solution has a concentration of 0.1-0.3 mol / L; The ferric chloride solution has a concentration of 0.05-0.07 mol / L; The sodium molybdate solution has a concentration of 0.05-0.08 mol / L.

5. The method for preparing a long-term repair agent for organic contaminated sites according to claim 1, characterized in that: The S2 comprises the following steps: Weigh 6-10g of phenol, 20-28mL of 37wt% formaldehyde solution and 150-230mL of 0.1-0.2mol / L sodium hydroxide solution, react at 45-47°C for 30-50min, add the obtained product and 9-13g of triblock polymer F127 into 150-200mL of deionized water, stir and react at 66-68°C for 2-5h, then add 500-600mL of deionized water and 2-5g of calcium peroxide-nanocore composite material, continue stirring for 16-20h, cool to room temperature, place the product in a hydrothermal kettle, hydrothermally react in an oven at 130-135°C for 24-30h, and after the reaction is completed, fully dry at 150-160°C.

6. The method for preparing a long-term repair agent for organic contaminated sites according to claim 5, characterized in that: The reaction is carried out in the high pressure reactor at a temperature of 130-135°C; The annealing temperature is 500-530°C; The dispersion has a solid content of 2-5wt%; The power of the ultrasonic effect is 100-150W.

7. The method for preparing a long-term repair agent for organic contaminated sites according to claim 1, characterized in that: The S4 comprises the following steps: 5-10g of composite mesoporous polymer core-shell microspheres are dispersed in 200-500mL of deionized water, 400-900mL of 1-3wt% dodecyltrimethylammonium bromide solution is added dropwise, magnetic stirring is performed for 1-3h, centrifugal washing is performed for 3-5 times, and then dispersed in deionized water to form a 1-3mg / mL dispersion, and then 30-40mL of the dispersion is added dropwise to 50-70mL of 4-6mg / mL sodium alginate solution, magnetic stirring is performed for 30-50min, centrifugal washing is performed for 3-5 times, and then dispersed in 50-70mL of 4-6mg / mL chitosan solution, the chitosan solution contains 1-2% acetic acid by volume and 2-3% calcium chloride by mass, magnetic stirring is performed for 30-50min, and then the precipitate is repeatedly washed with 1-2% acetic acid by volume and deionized water, and the precipitate is naturally dried.

8. A long-term remediation agent for organic contaminated sites prepared by the preparation method according to any one of claims 1 to 7.

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