Slow-release oxygen materials with hydrophobic shells, their preparation methods and applications

Abstract

This invention relates to the field of environmental pollution control technology, and discloses a slow-release oxygen material with a hydrophobic shell, its preparation method, and its application. The slow-release oxygen material provided by this invention has a uniform oxygen release rate, a long oxygen release cycle, and minimal impact on groundwater pH, thus significantly improving the in-situ remediation effect of organic pollution in groundwater.

Description

Technical Field

[0001] This invention relates to the field of environmental pollution control technology, specifically to a slow-release oxygen material with a hydrophobic shell, its preparation method, and its application. Background Technology

[0002] Organic pollution of soil and groundwater is a common environmental problem in the petrochemical industry. During the extraction, transportation, processing, and sale of oil, pollutants leak into the natural environment due to management oversights, lack of environmental awareness, and pipeline leaks, causing varying degrees of pollution to soil and groundwater. Moreover, such pollution often takes years or even decades to fully recover under natural conditions. Therefore, the remediation of polluted soil and groundwater has become an environmental, economic, and social problem that petrochemical companies worldwide must face.

[0003] Currently, the main methods for remediating organic pollutants in soil and groundwater include extraction, air disturbance, and chemical oxidation. However, these methods often require the use of large quantities of chemical agents or large-scale construction. These methods not only easily generate secondary pollutants such as wastewater and exhaust gases, but also clearly cannot meet the remediation needs of contaminated sites unsuitable for large-scale construction, such as urban gas stations and in-service chemical plants.

[0004] In recent years, in-situ bioremediation technology has gradually gained attention due to its advantages such as minimal site disturbance, low remediation cost, good remediation effect, and no secondary pollution. This technology mainly utilizes organic matter-degrading bacteria in soil and groundwater to degrade pollutants, achieving pollutant remediation. Key factors affecting the remediation effect include oxygen, moisture, temperature, and nutrients. Studies have shown that the aerobic degradation rate of petroleum pollutants is significantly higher than that of anaerobic pollutants. Since contaminated soil and groundwater are often in anaerobic or hypoxic environments, oxygen injection is usually required at contaminated sites to improve the effectiveness of in-situ remediation.

[0005] Currently, commonly used oxygen injection methods include air injection, hydrogen peroxide injection, colloidal microbubble method, and solid oxygen-releasing agent injection. Among these, solid oxygen-releasing agents are typically injected once, requiring no complex equipment or daily maintenance, making them more economical and effective. However, existing solid oxygen-releasing agents often suffer from problems such as excessively rapid oxygen release, uneven oxygen release rate, short oxygen release cycle, and low oxygen content, leading to poor remediation results. Moreover, some solid oxygen-releasing agents, while releasing oxygen, have a significant impact on the environmental pH value, adversely affecting microbial growth and organic matter decomposition, resulting in unsatisfactory in-situ remediation effects. Summary of the Invention

[0006] The purpose of this invention is to overcome the aforementioned problems of solid oxygen-releasing agents used in existing groundwater in-situ remediation technologies, and to provide a slow-release oxygen material with a hydrophobic shell, its preparation method, and its application. This slow-release oxygen material releases oxygen at a slow and uniform rate, has a long release cycle, and has minimal impact on the environment (e.g., pH value), thus significantly improving the in-situ remediation effect of organic pollutants in groundwater.

[0007] To achieve the above objectives, the present invention provides a slow-release oxygen material, which includes a hydrophobic outer shell material and an oxygen-releasing core material, wherein the particle size of the slow-release oxygen material does not exceed 50 μm, and the oxygen-releasing core material includes a carbon-based calcium peroxide composite material.

[0008] A second aspect of the present invention provides a method for preparing a slow-release oxygen material, the method comprising: first mixing an oxygen-releasing core material with a hydrophobic shell material, such that the oxygen-releasing core material is coated within the hydrophobic shell material, thereby obtaining a slow-release oxygen material with a particle size not exceeding 50 μm, wherein the oxygen-releasing core material comprises a carbon-based calcium peroxide composite material.

[0009] The third aspect of the present invention provides a slow-release oxygen material prepared by the method described above.

[0010] The fourth aspect of the present invention provides the application of the slow-release oxygen material as described above in soil and / or groundwater remediation, particularly in the remediation of organic pollution in soil and / or groundwater.

[0011] The fifth aspect of the present invention provides a method for remediating organic pollution in groundwater, the method comprising adding a slow-release oxygen material to groundwater containing organic pollutants, wherein the slow-release oxygen material is as described above.

[0012] Through the above technical solution, the present invention can achieve the following beneficial effects:

[0013] (1) The slow-release oxygen material provided by the present invention has a hydrophobic outer shell, thereby reducing the contact between the oxygen-releasing core material and water when it is added to groundwater, resulting in a longer oxygen release cycle.

[0014] (2) The slow-release oxygen material provided by the present invention preferably has a hydrophobic and oleophilic shell material, which reduces the contact between the oxygen-releasing core material and water, while improving the binding of the shell material with organic pollutants, reducing the consumption of the shell material in water, thereby further improving the oxygen release cycle.

[0015] (3) The slow-release oxygen material provided by the present invention uses carbon-based calcium peroxide composite material as the oxygen release core material. While releasing oxygen, it also has the functions of adsorbing organic pollutants and stimulating the biodegradation of organic pollutants, thus improving the remediation effect.

[0016] (4) The slow-release oxygen material provided by the present invention has a long oxygen release cycle, a relatively uniform oxygen release rate, and a small impact on the pH of the environment (e.g., groundwater), and will not have an adverse effect on the growth of microorganisms in groundwater or their decomposition of organic pollutants.

[0017] (5) The slow-release oxygen material provided by the present invention can be used directly. It can improve the in-situ remediation effect by promoting the degradation of organic pollutants by native microorganisms in groundwater. It does not require the injection of special microorganisms, which reduces the cost of in-situ remediation and has a wider range of applications.

[0018] (6) The raw materials for the slow-release oxygen material provided by the present invention are readily available, and the preparation and use methods are simple, making it suitable for large-scale industrial production and promotion. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] In this invention, the terms "first," "second," and "third" in "first mixing," "second mixing," "third mixing," "first drying," and "second drying" are used only to facilitate the distinction of corresponding operations in different steps or methods in the description.

[0021] The inventors of this invention ingeniously discovered during their research that by fabricating a core-shell composite material from oxygen-releasing solid compounds and hydrophobic materials, the contact between water and the oxygen-releasing solid compounds can be reduced when used for in-situ groundwater remediation, thereby extending the oxygen release cycle and improving the oxygen utilization efficiency of groundwater (native) microorganisms. Further research revealed that using specific oxygen-releasing solid compound composite materials (such as carbon-based oxygen-releasing compound composite materials) can not only further extend the oxygen release cycle but also improve the adsorption of pollutants and stimulate the growth of groundwater (native) microorganisms / pollutant degradation performance, thus achieving better in-situ remediation results.

[0022] In this invention, "carbon-based oxygen-releasing compound composite material" refers to a composite oxygen-releasing material composed of carbon-based substances and oxygen-releasing compounds, prepared by a specific composite method. The carbon-based substances can protect the oxygen-releasing compounds, reducing their contact with water, and can also possess other functions, such as adsorbing pollutants and stimulating microbial growth / degrading pollutants. For example, "carbon-based calcium peroxide composite material" is a composite oxygen-releasing material composed of carbon-based substances and calcium peroxide.

[0023] The present invention provides a slow-release oxygen material, which includes a hydrophobic outer shell material and an oxygen-releasing core material, wherein the particle size of the slow-release oxygen material does not exceed 50 μm, and the oxygen-releasing core material includes a carbon-based calcium peroxide composite material.

[0024] According to a preferred embodiment of the present invention, the (average) particle size of the slow-release oxygen material is 5-30 μm.

[0025] The inventors of this invention also discovered in their research that in core-shell composite materials made of oxygen-releasing solid compounds and hydrophobic materials, the ratio of the oxygen-releasing core material to the hydrophobic outer shell material has a significant impact on the cost and effectiveness of in-situ remediation. If the proportion of the oxygen-releasing core material is too low, the total oxygen release is too low, the oxygen release cycle decreases, requiring frequent injections and increasing maintenance and management costs. Furthermore, if the proportion of the outer shell material is too high (too thick), it can obstruct the contact between the oxygen-releasing core material and water, resulting in insufficient oxygen supply and unsatisfactory in-situ remediation. If the proportion of the hydrophobic outer shell material is too low, the outer shell will not adequately protect the core material, increasing the contact between the oxygen-releasing composite and water. This not only decreases the oxygen release cycle but may also lead to an excessively rapid oxygen release rate, reducing the oxygen utilization efficiency of groundwater (native) microorganisms. This results in a waste of slow-release oxygen material (increased costs) and a decrease in the effectiveness of in-situ remediation.

[0026] In order to balance the oxygen release rate and the total release amount and obtain a better in-situ remediation effect, according to a preferred embodiment of the present invention, the weight ratio of the oxygen-releasing core material to the hydrophobic shell material in the slow-release oxygen material is 3-50:1, preferably 3-20:1.

[0027] According to a preferred embodiment of the present invention, the calcium peroxide content in the slow-release oxygen material is 50% by weight or more.

[0028] Preferably, the calcium peroxide content in the slow-release oxygen material is 55-70% by weight.

[0029] Preferably, the thickness of the hydrophobic outer shell material in the slow-release oxygen material is 1-20 μm. More preferably, it is 5-10 μm.

[0030] In this invention, the carbon-based calcium peroxide composite material reduces the contact between calcium peroxide and water, delays oxygen release, and simultaneously enhances the adsorption of pollutants (such as petroleum-based organic pollutants) in groundwater through its carbon-based components, thereby improving the remediation effect. Any carbon-based calcium peroxide material with the above-mentioned functions can be applied to this invention. According to a preferred embodiment of the invention, the carbon-based calcium peroxide composite material is obtained by calcining a mixture of calcium peroxide and an organic binder. Preferably, the calcium peroxide content in the carbon-based calcium peroxide composite material is not less than 85% by weight, more preferably 90-95% by weight.

[0031] Preferably, the weight ratio of calcium peroxide to organic binder in the mixture is 5-50:1, more preferably 10-30:1.

[0032] In this invention, the purpose of calcination is to convert the organic binder into organic carbon, thereby enabling the carbon-based calcium peroxide composite material to adsorb organic pollutants. Any calcination conditions that achieve the aforementioned purpose are applicable to this invention. To ensure that the peroxide composition remains unchanged while facilitating the better decomposition and conversion of the organic binder into organic carbon, preferably, the calcination conditions include: a temperature of 210-250°C and a time of 5-20 minutes.

[0033] Preferably, the process for preparing the carbon-based calcium peroxide composite material further includes a step of drying the mixture before calcination. Preferably, the drying conditions include: a temperature of 100-120°C and a time of 30-60 minutes.

[0034] Preferably, the calcium peroxide is micron-sized calcium peroxide, with a preferred particle size of 5-20 μm.

[0035] In this invention, the aforementioned micron-sized calcium peroxide can be a commercially available product or can be prepared by the user according to existing technology.

[0036] According to a preferred embodiment of the present invention, the micron-sized calcium peroxide can be prepared by the following method: calcium hydroxide, a stabilizer and hydrogen peroxide are mixed in water to obtain calcium peroxide.

[0037] Preferably, the calcium hydroxide has a particle size of 5-20 μm.

[0038] Preferably, the weight ratio of calcium hydroxide to hydrogen peroxide is 0.8-2:1, more preferably 1-1.5:1.

[0039] In this invention, the stabilizer slows down the decomposition rate of hydrogen peroxide in the raw materials, allowing for a more complete reaction and improving the purity of the oxygen-releasing material (i.e., the obtained micron-sized calcium peroxide). Any compound capable of achieving the aforementioned effect can be used as a stabilizer in this invention. To buffer the pH of the peroxide aqueous solution and reduce direct contact between the peroxide and water, preferably, the stabilizer is selected from at least one of phosphates, silicates, carbonates, and acetates. More preferably, the weight ratio of the stabilizer to calcium hydroxide is 1:5-80, and more preferably 1:10-50.

[0040] More preferably, the stabilizer is water-soluble. That is, the stabilizer is selected from at least one of water-soluble phosphates (e.g., potassium phosphate, potassium dihydrogen phosphate, etc.), water-soluble silicates (e.g., sodium silicate, etc.), water-soluble carbonates (e.g., sodium carbonate, etc.), and water-soluble acetates (e.g., sodium acetate, potassium acetate, etc.).

[0041] For the purpose of a more complete reaction and reduced peroxide loss, the amount of water used is preferably such that the weight ratio of water to calcium hydroxide is 0.8-2:1, more preferably 1.1-1.5:1.

[0042] In order to ensure that calcium hydroxide, stabilizer and hydrogen peroxide can fully react in water during the third mixing process, and to control the decomposition rate of hydrogen peroxide, the conditions for the third mixing preferably include: temperature 0-40℃, time 10-40min, and stirring speed 200-900rpm.

[0043] More preferably, the conditions for the third mixing include: temperature 10-25°C, time 20-30 min, and stirring speed 500-800 rpm.

[0044] The inventors of this invention ingeniously discovered during their research that when natural colloidal substances (such as carrageenan, gelatin, xanthan gum, sodium alginate, etc.) are used as organic binders, the prepared material is more likely to form a slurry-like consistency during injection. Furthermore, the natural organic colloids, after being heated and decomposed, form an organic carbon coating layer that can adsorb pollutants. Therefore, in this invention, preferably, the organic binder is selected from at least one of carrageenan, gelatin, xanthan gum, and sodium alginate.

[0045] To further improve the in-situ remediation effect, increase the contact area with oily substances while reducing the contact area with water, and extend the service life of the material, according to a preferred embodiment of the present invention, the water contact angle of the slow-release oxygen material (using a hydrophobic shell material) is 130°-170°, preferably with a roll-off angle of less than 10°. That is, the contact angle between the hydrophobic shell material and water in the slow-release oxygen material is 130°-170°, preferably with a roll-off angle of less than 10°.

[0046] During the research process, the inventors of this invention also discovered that when the slow-release oxygen material (using a hydrophobic outer shell material) has a certain degree of oleophilicity, it can not only reduce the contact between the oxygen-releasing core material and water and prolong the oxygen release cycle, but also adsorb organic pollutants (such as petroleum-based organic pollutants) in groundwater, thereby further improving the effect of in-situ remediation.

[0047] To enhance the adsorption capacity of the slow-release oxygen material for organic pollutants (such as petroleum-based organic pollutants) in groundwater, the slow-release oxygen material (using a hydrophobic shell material) is preferably a hydrophobic and oleophilic substance.

[0048] More preferably, the slow-release oxygen material (using a hydrophobic shell material) has good contact with oily substances. Preferably, the oily substance is selected from at least one of gasoline, toluene, and 1,2-dichloroethane. More preferably, the contact angle between the slow-release oxygen material (using a hydrophobic shell material) and the oily substance in water is 0°-5°.

[0049] According to a preferred embodiment of the present invention, the hydrophobic and oleophilic composite material comprises a high molecular weight organic polymer, a silane coupling agent, and a hydrophobic agent.

[0050] Preferably, the high molecular weight organic polymer is selected from at least one of polyethylene, polyvinyl chloride, polyvinyl alcohol, polylactic acid, and polyethylene glycol. More preferably, the weight-average molecular weight of the high molecular weight organic polymer is 60,000-300,000, and more preferably 100,000-200,000.

[0051] More preferably, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the high molecular weight organic polymer in the hydrophobic shell material is 3-8:1, preferably 4-6:1.

[0052] Preferably, the silane coupling agent is selected from at least one of vinylsilane, aminosilane, methacryloxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and isobutyltriethoxysilane. In this invention, the silane coupling agent can be a commercially available product (e.g., KH550, KH560, etc.) or can be prepared using existing technology.

[0053] More preferably, the silane coupling agent is selected from γ-aminopropyltriethoxysilane (KH550) and / or isobutyltriethoxysilane.

[0054] More preferably, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the silane coupling agent in the hydrophobic shell material is 100-250:1, preferably 150-220:1.

[0055] Preferably, the hydrophobic agent is selected from hydrophobic nanoparticles, and more preferably hydrophobic nano-silica.

[0056] More preferably, the particle size of the hydrophobic agent is 40-120 nm. More preferably, it is 60-100 nm.

[0057] More preferably, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the hydrophobic agent in the hydrophobic shell material is 5-20:1, preferably 10-15:1.

[0058] According to a preferred embodiment of the present invention, the weight ratio of the high molecular weight organic polymer, the hydrophobic agent and the silane coupling agent in the hydrophobic shell material is 20-40:10-25:1, preferably 25-35:15-20:1.

[0059] In this invention, the slow-release oxygen material may also contain residual organic solvents from the preparation process.

[0060] According to a preferred embodiment of the present invention, the organic solvent is selected from at least one of carbon tetrachloride, dichloromethane, and tetrahydrofuran.

[0061] Preferably, the total residual amount (content) of organic solvent in the slow-release oxygen material does not exceed 2% by weight of the total weight of the slow-release oxygen material, and more preferably 0.5-1% by weight.

[0062] A second aspect of the present invention provides a method for preparing a slow-release oxygen material, the method comprising: mixing an oxygen-releasing core material and a hydrophobic shell material in the presence of an organic solvent, such that the oxygen-releasing core material is coated within the hydrophobic shell material, thereby obtaining a slow-release oxygen material with a particle size not exceeding 50 μm, wherein the oxygen-releasing core material comprises a carbon-based calcium peroxide composite material.

[0063] According to a preferred embodiment of the present invention, the weight ratio of the oxygen-releasing core material to the hydrophobic shell material is 3-50:1, preferably 3-20:1.

[0064] In this invention, there are no particular limitations on the first mixing method, as long as it enables the hydrophobic shell material to uniformly coat the oxygen-releasing core material. According to a preferred embodiment of the invention, the first mixing method includes: adding the oxygen-releasing core material to the hydrophobic shell material dispersed in an organic solvent, and stirring to obtain a slow-release oxygen material dispersion.

[0065] Preferably, the stirring and dispersion conditions result in an average particle size of 5-30 μm for the slow-release oxygen material. Preferably, the thickness of the hydrophobic outer shell material coating the surface of the oxygen-releasing core material is 1-20 μm, more preferably 5-10 μm.

[0066] Preferably, the stirring and dispersion conditions include a stirring speed of 500-800 rpm. In this invention, the stirring and dispersion time is only required to ensure that the oxygen-releasing core material and the hydrophobic shell material dispersed in the organic solvent are uniformly dispersed; for example, the stirring time can be 20-30 minutes. The stirring time may vary depending on the preparation quantity, etc. In actual operation, the stirring time can be adjusted according to the actual situation (e.g., preparation quantity, degree of mixing, etc.).

[0067] According to a preferred embodiment of the present invention, the method further includes the step of first drying the slow-release oxygen material dispersion to obtain the slow-release oxygen material.

[0068] Preferably, the first drying method ensures that the total organic solvent content in the slow-release oxygen material does not exceed 2% by weight. More preferably, it is 0.5-1% by weight.

[0069] More preferably, the first drying method includes air drying at 20-30°C under fume hood conditions. Preferably, the fume hood conditions include an air velocity of 0.4-0.8 m / s, more preferably 0.4-0.6 m / s.

[0070] Any organic solvent that does not adversely affect the properties and effects of carbon-based calcium peroxide composite materials can be used in the method provided by this invention. Considering the solubility of the high molecular weight organic polymers in the raw materials, according to a preferred embodiment of this invention, the organic solvent is selected from at least one of carbon tetrachloride, dichloromethane, and tetrahydrofuran.

[0071] Preferably, the weight ratio of the oxygen-releasing core material to the organic solvent is 0.2-0.8:1, and more preferably 0.3-0.5:1.

[0072] According to a preferred embodiment of the present invention, the contact angle of the hydrophobic shell material is 120-160°, and preferably the hydrophobic shell material is a hydrophobic and oleophilic composite material.

[0073] Preferably, the hydrophobic shell material is a hydrophobic and oleophilic composite material. More preferably, the hydrophobic shell material has good contact with oily substances, wherein the oily substance is preferably selected from at least one of gasoline, toluene, and 1,2-dichloroethane. More preferably, the contact angle between the hydrophobic shell material and the oily substance in water is 0°-5°.

[0074] Preferably, the hydrophobic and oleophilic composite material comprises a high molecular weight organic polymer, a silane coupling agent, and a hydrophobic agent.

[0075] Preferably, the high molecular weight organic polymer is selected from at least one of polyethylene, polyvinyl chloride, polyvinyl alcohol, polylactic acid, and polyethylene glycol. More preferably, the weight-average molecular weight of the high molecular weight organic polymer is 60,000-300,000, and more preferably 100,000-200,000.

[0076] More preferably, the weight ratio of the oxygen-releasing core material to the high molecular weight organic polymer is 3-8:1, and more preferably 4-6:1.

[0077] Preferably, the silane coupling agent is selected from at least one of vinylsilane, aminosilane, methacryloxysilane, γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), and isobutyltriethoxysilane. More preferably, it is KH550 and / or isobutyltriethoxysilane.

[0078] More preferably, the weight ratio of the oxygen-releasing core material to the silane coupling agent is 100-250:1, and more preferably 150-220:1.

[0079] Preferably, the hydrophobic agent is selected from hydrophobic nanoparticles (preferably with a particle size of 40-120 nm, more preferably 60-100 nm), and more preferably hydrophobic nano-silica.

[0080] More preferably, the weight ratio of the oxygen-releasing core material to the hydrophobic agent is 5-20:1, and more preferably 10-15:1.

[0081] According to a preferred embodiment of the present invention, the method further includes the step of preparing a carbon-based calcium peroxide composite material.

[0082] This invention does not impose any particular limitation on the specific method for preparing carbon-based calcium peroxide composite materials. Preferably, the method for preparing carbon-based calcium peroxide composite materials includes: performing a second mixing of calcium peroxide and an organic binder, followed by a second drying and calcination.

[0083] According to a preferred embodiment of the present invention, the calcium peroxide is micron-sized calcium peroxide, preferably with a particle size of 5-20 μm.

[0084] In this invention, the organic binder serves to bind the aforementioned micron-sized calcium peroxide into aggregates and to provide carbon-based materials for the carbon-based calcium peroxide composite material. Any organic binder capable of performing the above-mentioned function is applicable to this invention. According to a preferred embodiment of the invention, the organic binder is selected from at least one of carrageenan, gelatin, xanthan gum, and sodium alginate.

[0085] Preferably, the weight ratio of calcium peroxide to organic binder is 5-50:1, more preferably 10-30:1.

[0086] Preferably, the conditions for the second mixing include a stirring speed of 300-1000 rpm. The mixing time for the second mixing is sufficient to allow the calcium peroxide and organic binder to mix repeatedly, for example, 20-40 minutes, preferably 20-30 minutes. In actual operation, the mixing time for the second mixing can be adjusted according to the actual situation (e.g., the amount prepared, the degree of mixing of calcium peroxide and organic binder, etc.).

[0087] More preferably, the conditions for the second mixing include: a stirring speed of 500-800 rpm.

[0088] Preferably, the conditions for the second drying include: a temperature of 100-120°C and a time of 30-60 minutes.

[0089] Preferably, the calcination conditions include: a temperature of 210-250℃ and a time of 5-20 minutes.

[0090] In this invention, calcium peroxide can be a commercially available product or can be prepared using existing technology. For example, micron-sized calcium peroxide can be prepared using the methods described above. The characteristics and preparation method of this micron-sized calcium peroxide are as previously described and will not be repeated here.

[0091] A third aspect of this invention provides a slow-release oxygen material prepared by the method described above. This slow-release oxygen material is the same as the slow-release oxygen material provided by this invention, and its characteristics are as described above, and will not be repeated here.

[0092] The fourth aspect of the present invention provides the application of the slow-release oxygen material as described above in soil and / or groundwater remediation, particularly in the remediation of organic pollution in soil and / or groundwater.

[0093] Preferably, the pollutants causing organic pollution of the soil and / or groundwater include petroleum-based (organic) pollutants. Preferably, the petroleum-based pollutants are selected from at least one of volatile organic pollutants, semi-volatile organic pollutants, polycyclic aromatic hydrocarbons, and ethers.

[0094] More preferably, the petroleum pollutant is selected from at least one of benzene, toluene, ethylbenzene, trimethylbenzene, methyl tert-butyl ether, dichloroethane, trimethylbenzene, and benzo[a]pyrene.

[0095] The fifth aspect of the present invention provides a method for remediating organic pollution in groundwater, the method comprising adding a slow-release oxygen material to groundwater containing organic pollutants, wherein the slow-release oxygen material is as described above.

[0096] According to a preferred embodiment of the present invention, the organic pollutant is a petroleum-based pollutant.

[0097] Preferably, the petroleum pollutants are selected from at least one of volatile organic pollutants, semi-volatile organic pollutants, polycyclic aromatic hydrocarbons, and ethers.

[0098] More preferably, the petroleum pollutants are selected from at least one of benzene, toluene, ethylbenzene, trimethylbenzene, methyl tert-butyl ether, dichloroethane, trimethylbenzene, and benzo[a]pyrene. Preferably, the total concentration of organic pollutants in the groundwater is above 100 ppm (i.e., the total content of organic pollutants in each ton of groundwater is above 100 g), more preferably 100-2000 ppm.

[0099] In the method provided by this invention, there is no particular limitation on the amount of the slow-release oxygen material used. According to a preferred embodiment of the invention, the amount of the slow-release oxygen material added is 0.2-1.2% by weight of the pollutants contained in the groundwater, preferably 0.5-1% by weight.

[0100] The present invention will be described in detail below through embodiments. It should be understood that the following embodiments are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0101] In the following examples, the calcium hydroxide used had a particle size of approximately 4 ± 2 μm. Hydrophobic nano-silica was purchased from Sinopharm (CAS No. 60676-86-0) with a particle size of approximately 80 ± 40 nm. Unless otherwise specified, all chemical reagents used were purchased from reputable chemical suppliers and were of analytical grade.

[0102] In the following embodiments, unless otherwise specified, the operating temperature is room temperature (25±5℃). The fume hood conditions include: room temperature and air velocity of 0.5±0.1m / s.

[0103] Example 1

[0104] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 17.2 g of solid calcium hydroxide and 0.65 g of potassium phosphate trihydrate, mix thoroughly and add to a three-necked flask. Add 20.8 g of deionized water, stir evenly and place in a constant temperature reactor. Set the reaction temperature to 20 °C and the stirring speed to 700 rpm. Add 22 mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 700 rpm for 30 min to obtain a micron-sized calcium peroxide suspension.

[0105] (2) Preparation of carbon-based calcium peroxide composite material: Add 0.864 g of carrageenan to the micron-sized calcium peroxide suspension obtained in step (1), stir at 700 rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 110°C for 50 min, place the dried sample in a crucible, calcine it in a muffle furnace at 220°C for 10 min to obtain carbon-based calcium peroxide composite material.

[0106] (3) Preparation of sustained-release oxygen material: Accurately weigh 2.75 g of polylactic acid (weight average molecular weight approximately 150,000), mix it evenly with 50 mL of tetrahydrofuran in a fume hood, stir until evenly dispersed, add 1.38 g of hydrophobic nano-silica, stir evenly, then add 0.06 g of KH550, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (700 rpm, 30 min) to obtain a sustained-release oxygen material dispersion. Air dry under fume hood conditions to obtain sustained-release oxygen material A1.

[0107] Example 2

[0108] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 16.4 g of solid calcium hydroxide and 0.47 g of sodium silicate nonahydrate, mix thoroughly and add to a three-necked flask. Add 24.6 g of deionized water, stir evenly and place in a constant temperature reactor. Set the reaction temperature to 20 °C and the stirring speed to 800 rpm. Add 23 mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 700 rpm for 30 min to obtain a micron-sized calcium peroxide suspension.

[0109] (2) Preparation of carbon-based calcium peroxide composite material: Add 0.66g xanthan gum to the micron-sized calcium peroxide suspension obtained in step (1), stir at 700rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 110℃ for 40min, place the dried sample in a crucible, calcine it in a muffle furnace at 210℃ for 5min to obtain carbon-based calcium peroxide composite material.

[0110] (3) Preparation of slow-release oxygen material: Accurately weigh 2.6 g of polyvinyl chloride (weight average molecular weight approximately 150,000), mix it evenly with 60 mL of tetrahydrofuran in a fume hood, stir until evenly dispersed, add 0.89 g of hydrophobic nano-silica, stir evenly, then add 0.07 g of isobutyltriethoxysilane, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (600 rpm, 20 min) to obtain a slow-release oxygen material dispersion. Air dry under fume hood conditions to obtain slow-release oxygen material A2.

[0111] Example 3

[0112] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 20g of solid calcium hydroxide and 0.6g of sodium carbonate, mix thoroughly and add to a three-necked flask. Add 26g of deionized water, stir evenly and place in a constant temperature reactor. Set the reaction temperature to 10℃ and the stirring speed to 700rpm. Add 23mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 700rpm for 20min to obtain a micron-sized calcium peroxide suspension.

[0113] (2) Preparation of carbon-based calcium peroxide composite material: Add 0.8g sodium alginate to the micron-sized calcium peroxide suspension obtained in step (1), stir at 700rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 110℃ for 50min, place the dried sample in a crucible, calcine it in a muffle furnace at 220℃ for 10min to obtain carbon-based calcium peroxide composite material.

[0114] (3) Preparation of slow-release oxygen material: Accurately weigh 3.2g of polyethylene (weight average molecular weight approximately 160,000), mix it evenly with 50mL of carbon tetrachloride in a fume hood, stir until evenly dispersed, add 1.02g of hydrophobic nano-silica, stir evenly, then add 0.08g of KH550, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (600rpm, 25min) to obtain a slow-release oxygen material dispersion. Air dry under fume hood conditions to obtain slow-release oxygen material A3.

[0115] Example 4

[0116] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 20g of solid calcium hydroxide and 1g of potassium dihydrogen phosphate, mix thoroughly and add to a three-necked flask. Add 24g of deionized water, stir evenly and place in a constant temperature reactor. Set the reaction temperature to 20℃ and the stirring speed to 900rpm. Add 30mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 900rpm for 30min to obtain a micron-sized calcium peroxide suspension.

[0117] (2) Preparation of carbon-based calcium peroxide composite material: Add 1g of carrageenan to the micron-sized calcium peroxide suspension obtained in step (1), stir at 700rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 110℃ for 40min, place the dried sample in a crucible, calcine it in a muffle furnace at 220℃ for 5min to obtain carbon-based calcium peroxide composite material.

[0118] (3) Preparation of sustained-release oxygen material: Accurately weigh 2.7g of polylactic acid (weight average molecular weight approximately 150,000), mix it evenly with 40mL of dichloroethane in a fume hood, stir until evenly dispersed, add 0.8g of hydrophobic nano-silica, stir evenly, then add 0.07g of KH560, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (800rpm, 30min) to obtain a sustained-release oxygen material dispersion. Air dry under fume hood conditions to obtain sustained-release oxygen material A4.

[0119] Example 5

[0120] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 20g of solid calcium hydroxide and 0.4g of sodium acetate, mix them thoroughly, and add them to a three-necked flask. Add 30g of deionized water, stir evenly, and place the flask in a constant temperature reactor. Set the reaction temperature to 10℃ and the stirring speed to 700rpm. Add 28mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 700rpm for 30min to obtain a micron-sized calcium peroxide suspension.

[0121] (2) Preparation of carbon-based calcium peroxide composite material: Add 0.67g xanthan gum to the micron-sized calcium peroxide suspension obtained in step (1), stir at 600rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 120℃ for 30min, place the dried sample in a crucible, calcine it in a muffle furnace at 210℃ for 10min to obtain carbon-based calcium peroxide composite material.

[0122] (3) Preparation of slow-release oxygen material: Accurately weigh 2.3g of polyvinyl chloride (weight average molecular weight approximately 150,000), mix it evenly with 40mL of carbon tetrachloride in a fume hood, stir until evenly dispersed, add 0.9g of hydrophobic nano-silica, stir evenly, then add 0.08g of KH550, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (700rpm, 20min) to obtain a slow-release oxygen material dispersion. Air dry under fume hood conditions to obtain slow-release oxygen material A5.

[0123] Example 6

[0124] (1) Preparation of micron-sized calcium peroxide: Accurately weigh 20g of solid calcium hydroxide and 0.8g of sodium dihydrogen phosphate, mix thoroughly and add to a three-necked flask. Add 28g of deionized water, stir evenly and place in a constant temperature reactor. Set the reaction temperature to 20℃ and the stirring speed to 800rpm. Add 30mL of hydrogen peroxide solution (purity 30%) through a peristaltic pump. After the hydrogen peroxide is added, continue stirring at 800rpm for 20min to obtain a micron-sized calcium peroxide suspension.

[0125] (2) Preparation of carbon-based calcium peroxide composite material: Add 1g of gelatin to the micron-sized calcium peroxide suspension obtained in step (1), stir at 600rpm until a uniform liquid slurry is obtained, place it in a desiccator, dry it in a vacuum drying oven at 110℃ for 40min, place the dried sample in a crucible, calcine it in a muffle furnace at 220℃ for 10min to obtain carbon-based calcium peroxide composite material.

[0126] (3) Preparation of sustained-release oxygen material: Accurately weigh 3.2 g of polyvinyl alcohol (weight average molecular weight approximately 160,000), mix it evenly with 45 mL of tetrahydrofuran in a fume hood, stir until evenly dispersed, add 0.9 g of hydrophobic nano-silica, stir evenly, then add 0.09 g of KH560, mix evenly, then add the carbon-based calcium peroxide composite material obtained in step (2), stir and disperse (600 rpm, 20 min) to obtain a sustained-release oxygen material dispersion. Air dry under fume hood conditions to obtain sustained-release oxygen material A6.

[0127] Example 7

[0128] The method described in Example 1 was used, except that hydrophobic nano-silica was not added in step (3), while the other steps and conditions were the same as in Example 1. Slow-release oxygen material A7 was obtained.

[0129] Example 8

[0130] The method described in Example 1 was used, except that in step (3), an equal weight of ordinary nano-silica (particle size 100±20nm, without hydrophobic modification groups) was used instead of hydrophobic nano-silica. All other steps and conditions were the same as in Example 1. Slow-release oxygen material A8 was obtained.

[0131] Example 9

[0132] The method described in Example 1 was used, except that carrageenan in step (2) was replaced with ethyl cellulose, while all other steps and conditions were the same as in Example 1. Slow-release oxygen material A9 was obtained.

[0133] Example 10

[0134] The method described in Example 1 was used, except that the amount of carrageenan in step (2) was adjusted to 0.31 g, while the other steps and conditions were the same as in Example 1. Slow-release oxygen material A10 was obtained.

[0135] Example 11

[0136] The method described in Example 1 was used, except that the amount of carrageenan in step (2) was adjusted to 3.48 g, while the other steps and conditions were the same as in Example 1. Slow-release oxygen material A11 was obtained.

[0137] Example 12

[0138] The method described in Example 1 was used, except that the amounts of calcium hydroxide, potassium phosphate trihydrate, and deionized water in step (1) were adjusted to 17.2 g, 0.28 g, and 37.8 g, respectively, and the amount of carrageenan in step (2) was adjusted to 0.31 g. All other steps and conditions were the same as in Example 1. Slow-release oxygen material A12 was obtained.

[0139] Example 13

[0140] The method described in Example 1 was used, except that the amounts of calcium hydroxide, potassium phosphate trihydrate, and deionized water in step (1) were adjusted to 17.2 g, 2.16 g, and 12.04 g, respectively, and the amount of carrageenan in step (2) was adjusted to 3.48 g. All other steps and conditions were the same as in Example 1. Slow-release oxygen material A13 was obtained.

[0141] Example 14

[0142] The method described in Example 1 was used, except that carrageenan was not added in step (2), while the other steps and conditions were the same as in Example 1. Slow-release oxygen material A14 was obtained.

[0143] Example 15

[0144] The method described in Example 1 was used, except that carrageenan in step (2) was replaced with silica sol, while all other steps and conditions were the same as in Example 1. Slow-release oxygen material A15 was obtained.

[0145] Comparative Example 1

[0146] The method described in Example 1 is used, except that step (3) is omitted, while all other steps and conditions are the same as in Example 1. Slow-release oxygen material D1 is obtained. That is, slow-release oxygen material D1 does not contain a hydrophobic shell material.

[0147] Test Example 1

[0148] The particle size of the slow-release oxygen materials obtained in the above embodiments and comparative examples was detected using a laser particle size analyzer.

[0149] The calcium peroxide content in the slow-release oxygen materials obtained in the above examples and comparative examples was determined by potassium permanganate titration. The specific steps included: accurately weighing 0.06-0.07 g of the sample, wetting it with 10 ml of water, then adding 20 ml of phosphoric acid solution (ratio 1:3) to completely dissolve the sample. Titration was performed with 0.02 mol / L potassium permanganate standard solution until the pink color persisted for 30 seconds, which was the endpoint.

[0150] The oxygen release cycle of the slow-release oxygen materials obtained in the above examples and comparative examples was tested using a static slow-release test. The specific steps included: accurately weighing a certain mass of calcium peroxide product, determining its initial purity, placing it in deionized water at a concentration of 1% (w / v), letting it stand for a period of time, filtering and drying it, re-titering its purity, and calculating its oxygen release cycle.

[0151] The thickness of the hydrophobic shell material was measured using scanning electron microscopy. The dissolved oxygen content was measured using a Mettler S900-K analyzer.

[0152] For detailed test results, please refer to Table 1.

[0153] Table 1

[0154]

[0155] *The remaining amount of calcium peroxide refers to the percentage (by weight) of calcium peroxide content in the material at the end of the static sustained-release test relative to the initial content.

[0156] Dissolved oxygen content refers to the weight of dissolved oxygen in one liter of water (i.e., 1 ppm = 1 mg / L).

[0157] The water contact angle, roll-off angle, and contact angle with oily substances (gasoline, toluene, and 1,2-dichloroethane) of the slow-release oxygen material were measured using a water droplet angle meter (Odellino OCA15EC model). The test results are detailed in Table 2.

[0158] Table 2

[0159]

[0160]

[0161] Test Example 2

[0162] The dissolved oxygen concentration in the water sample was detected using the method described in Test Example 1, and the types and contents of pollutants in the water sample were detected using a gas chromatography-mass spectrometry (Thermo Fisher Scientific ISQ LT model).

[0163] Groundwater contaminated with benzene, toluene, and ethylbenzene from a chemical refining plant was collected and tested. The initial total concentration of pollutants was 132 ppm (i.e., the total content of benzene, toluene, and ethylbenzene in each ton of groundwater was 132 g).

[0164] In a vacuum glove box, contaminated groundwater was mixed with the slow-release oxygen materials obtained in the above examples and comparative examples, respectively, at a mixing ratio of 1% w / v (i.e., 10g of slow-release oxygen material was added to 1L of contaminated groundwater). The mixture was placed in a brown glass bottle, with no air at the top, and placed in a 20°C constant temperature incubator to react in the dark.

[0165] Dissolved oxygen concentration and total pollutant concentration in water samples were measured at 1 month, 3 months, 6 months, and 9 months. The results are detailed in Table 3.

[0166] Table 3

[0167]

[0168]

[0169] *No slow-release oxygen material was added to the control group.

[0170] Test Example 3

[0171] The in-situ remediation capacity of the slow-release oxygen materials obtained in the above examples and comparative examples was tested using the method described in Test Example 3. The difference was that the test water sample was petroleum-contaminated groundwater taken from a petrochemical site, containing the main pollutants including petroleum hydrocarbons (980 ppm), dichloroethane (270 ppm), and benzo[a]pyrene (20 ppm). The test results are detailed in Tables 4 and 5 (contaminant content after 9 months of reaction).

[0172] Table 4

[0173]

[0174] *No slow-release oxygen material was added to the control group.

[0175] Table 5

[0176] serial number Petroleum hydrocarbons / ppm dichloroethane / ppm Benzo[a]pyrene / ppm A1 143 39 4 A2 146 37 6 A3 142 41 5 A4 147 40 5 A5 148 36 6 A6 150 38 4 A7 168 47 8 A8 166 49 9 A9 167 44 7 A10 170 43 6 A11 164 42 6 A12 166 40 7 A13 167 44 6 A14 178 51 10 A15 176 50 11 D1 181 47 12 Comparison* 899 218 17

[0177] *No slow-release oxygen material was added to the control group.

[0178] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A slow-release oxygen material, characterized in that, The slow-release oxygen material includes a hydrophobic outer shell material and an oxygen-releasing core material, wherein the particle size of the slow-release oxygen material does not exceed 50 μm, and the oxygen-releasing core material includes a carbon-based calcium peroxide composite material. The slow-release oxygen material contains 55-70% by weight of calcium peroxide. In the slow-release oxygen material, the thickness of the hydrophobic outer shell material is 1-20 μm; The carbon-based calcium peroxide composite material is obtained by calcining a mixture of calcium peroxide and an organic binder, wherein the organic binder is selected from at least one of carrageenan, gelatin, xanthan gum and sodium alginate; The water contact angle of the slow-release oxygen material is 130°-170°.

2. The slow-release oxygen material according to claim 1, wherein, The particle size of the slow-release oxygen material is 5-30 μm.

3. The slow-release oxygen material according to claim 1, wherein, In the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the hydrophobic outer shell material is 3-50:

1.

4. The slow-release oxygen material according to any one of claims 1-3, wherein, In the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the hydrophobic outer shell material is 3-20:1; And / or, in the slow-release oxygen material, the thickness of the hydrophobic shell material is 5-10 μm.

5. The slow-release oxygen material according to claim 1, wherein, The calcium peroxide is micron-sized calcium peroxide; And / or, in the mixture, the weight ratio of calcium peroxide to organic binder is 5-50:1; And / or, the calcination conditions include: a temperature of 210-250°C and a time of 5-20 min.

6. The slow-release oxygen material according to claim 5, wherein, The particle size of the calcium peroxide is 5-20 μm; And / or, in the mixture, the weight ratio of calcium peroxide to organic binder is 10-30:

1.

7. The slow-release oxygen material according to claim 1, wherein, The rolling angle of the slow-release oxygen material is less than 10°.

8. The slow-release oxygen material according to claim 1, wherein, The slow-release oxygen material is a hydrophobic and oleophilic composite material.

9. The slow-release oxygen material according to claim 8, wherein, The contact angle between the slow-release oxygen material and oily substances in water is 0°-5°.

10. The slow-release oxygen material according to claim 9, wherein, The oily substance is selected from at least one of gasoline, toluene, and 1,2-dichloroethane.

11. The slow-release oxygen material according to claim 8, wherein, The hydrophobic and oleophilic composite material includes a high molecular weight organic polymer, a silane coupling agent, and a hydrophobic agent.

12. The slow-release oxygen material according to claim 11, wherein, The high molecular weight organic polymer is selected from at least one of polyethylene, polyvinyl chloride, polyvinyl alcohol, polylactic acid and polyethylene glycol; And / or, the silane coupling agent is selected from at least one of vinylsilane, aminosilane, methacryloxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and isobutyltriethoxysilane; And / or, the hydrophobic agent is selected from hydrophobic nanoparticles.

13. The slow-release oxygen material according to claim 12, wherein, The weight-average molecular weight of the high molecular weight organic polymer is 60,000 to 300,000. And / or, the hydrophobic agent is hydrophobic nano-silica.

14. The slow-release oxygen material according to claim 11, wherein, In the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the high-molecular organic polymer in the hydrophobic outer shell material is 3-8:1; And / or, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the silane coupling agent in the hydrophobic shell material is 100-250:1; And / or, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the hydrophobic agent in the hydrophobic shell material is 5-20:1; And / or, in the hydrophobic shell material, the weight ratio of the high molecular weight organic polymer, the hydrophobic agent and the silane coupling agent is 20-40:10-25:

1.

15. The slow-release oxygen material according to claim 14, wherein, In the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the high-molecular organic polymer in the hydrophobic outer shell material is 4-6:1; And / or, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the silane coupling agent in the hydrophobic shell material is 150-220:1; And / or, in the slow-release oxygen material, the weight ratio of the oxygen-releasing core material to the hydrophobic agent in the hydrophobic shell material is 10-15:1; And / or, in the hydrophobic shell material, the weight ratio of the high molecular weight organic polymer, the hydrophobic agent and the silane coupling agent is 25-35:15-20:

1.

16. A method for preparing a slow-release oxygen material, characterized in that, The method includes: mixing an oxygen-releasing core material and a hydrophobic shell material in the presence of an organic solvent, such that the oxygen-releasing core material is coated within the hydrophobic shell material, to obtain a slow-release oxygen material with a particle size not exceeding 50 μm, wherein the oxygen-releasing core material includes a carbon-based calcium peroxide composite material. The method for preparing carbon-based calcium peroxide composite material includes: second mixing calcium peroxide and organic binder, followed by second drying and calcination; The organic binder is selected from at least one of carrageenan, gelatin, xanthan gum, and sodium alginate; The water contact angle of the hydrophobic shell material is 130°-170°.

17. The method according to claim 16, wherein, The weight ratio of the oxygen-releasing core material to the hydrophobic outer shell material is 3-50:1; And / or, the first mixing method includes: adding an oxygen-releasing core material to a hydrophobic shell material dispersed in an organic solvent, and stirring to disperse and obtain a slow-release oxygen material dispersion.

18. The method according to claim 17, wherein, The weight ratio of the oxygen-releasing core material to the hydrophobic outer shell material is 3-20:1; And / or, the stirring and dispersion conditions result in a particle size of 5-30 μm for the slow-release oxygen material.

19. The method of claim 17, wherein, The method further includes the step of first drying the slow-release oxygen material dispersion to obtain the slow-release oxygen material.

20. The method of claim 17, wherein, The conditions for stirring and dispersing include: stirring speed of 500-800 rpm.

21. The method according to claim 19, wherein, The first drying method ensures that the organic solvent content in the slow-release oxygen material does not exceed 2% by weight.

22. The method according to claim 19, wherein, The first drying method includes air drying at 20-30°C under fume hood conditions.

23. The method according to claim 22, wherein, The fume hood conditions include an air velocity of 0.4-0.8 m / s.

24. The method according to claim 16 or 17, wherein, The organic solvent is selected from at least one of carbon tetrachloride, dichloromethane, and tetrahydrofuran; And / or, the roll-off angle of the hydrophobic shell material is less than 10°; And / or, the weight ratio of the oxygen-releasing core material to the organic solvent is 0.2-0.8:

1.

25. The method according to claim 24, wherein, The weight ratio of the oxygen-releasing core material to the organic solvent is 0.3-0.5:

1.

26. The method according to claim 16 or 17, wherein, The hydrophobic shell material is a hydrophobic and oleophilic composite material.

27. The method according to claim 26, wherein, The hydrophobic and oleophilic composite material includes a high molecular weight organic polymer, a silane coupling agent, and a hydrophobic agent.

28. The method according to claim 27, wherein, The high molecular weight organic polymer is selected from at least one of polyethylene, polyvinyl chloride, polyvinyl alcohol, polylactic acid and polyethylene glycol; And / or, the silane coupling agent is selected from at least one of vinylsilane, aminosilane, methacryloxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and isobutyltriethoxysilane; And / or, the hydrophobic agent is selected from hydrophobic nanoparticles.

29. The method according to claim 27, wherein, The weight-average molecular weight of the high molecular weight organic polymer is 60,000 to 300,000. And / or, the hydrophobic agent is hydrophobic nano-silica.

30. The method according to claim 26, wherein, The hydrophobic shell material has a contact angle of 0°-5° with oily substances in water.

31. The method according to claim 30, wherein, The oily substance is selected from at least one of gasoline, toluene, and 1,2-dichloroethane.

32. The method according to claim 27, wherein, The weight ratio of the oxygen-releasing core material to the high-molecular organic polymer is 3-8:1; And / or, the weight ratio of the oxygen-releasing core material to the silane coupling agent is 100-250:1; And / or, the weight ratio of oxygen-releasing core material to hydrophobic agent is 5-20:

1.

33. The method according to claim 27, wherein, The weight ratio of the oxygen-releasing core material to the high-molecular organic polymer is 4-6:1; And / or, the weight ratio of the oxygen-releasing core material to the silane coupling agent is 150-220:1; And / or, the weight ratio of the oxygen-releasing core material to the hydrophobic agent is 10-15:

1.

34. The method according to claim 16, wherein, The calcium peroxide is micron-sized calcium peroxide; And / or, the weight ratio of calcium peroxide to organic binder is 5-50:1; And / or, the conditions for the second mixing include: a stirring speed of 300-1000 rpm; And / or, the conditions for the second drying include: a temperature of 100-120°C and a time of 30-60 min; And / or, the calcination conditions include: a temperature of 210-250°C and a time of 5-20 min.

35. The method according to claim 16, wherein, The particle size of the calcium peroxide is 5-20 μm; And / or, the weight ratio of calcium peroxide to organic binder is 10-30:

1.

36. The method according to claim 16, wherein, The method also includes a step of preparing calcium peroxide.

37. The method of claim 36, wherein, One method for preparing calcium peroxide is to perform a third mixing of calcium hydroxide, a stabilizer, and hydrogen peroxide in water to obtain calcium peroxide.

38. The method according to claim 37, wherein, The calcium hydroxide has a particle size of 5-20 μm; And / or, the weight ratio of calcium hydroxide to hydrogen peroxide is 0.8-2:1; And / or, the stabilizer is selected from at least one of phosphates, silicates, carbonates and acetates; And / or, the amount of water used is such that the weight ratio of water to calcium hydroxide is 0.8-2:

1.

39. The method according to claim 37, wherein, The weight ratio of calcium hydroxide to hydrogen peroxide is 1-1.5:1; And / or, the weight ratio of the stabilizer to calcium hydroxide is 1:5-80; And / or, the amount of water used is such that the weight ratio of water to calcium hydroxide is 1.1-1.5:1; And / or, the conditions for the third mixing include: temperature 0-40℃, time 10-40min, and stirring speed 200-900rpm.

40. The method of claim 37, wherein, The weight ratio of the stabilizer to calcium hydroxide is 1:10-50.

41. The slow-release oxygen material prepared by the method according to any one of claims 16-40.

42. The use of the slow-release oxygen material according to any one of claims 1-15 and 41 in soil and / or groundwater remediation.

43. The application according to claim 42, wherein, The application is in the remediation of organic pollution in soil and / or groundwater.

44. A method for remediating organic pollution in groundwater, characterized in that, The method includes adding a slow-release oxygen material to groundwater containing organic pollutants, wherein the slow-release oxygen material is the slow-release oxygen material according to any one of claims 1-15 and 41.

45. The method according to claim 44, wherein, The organic pollutants include petroleum-based pollutants.

46. ​​The method according to claim 45, wherein, The petroleum pollutants are selected from at least one of volatile organic pollutants, semi-volatile organic pollutants, polycyclic aromatic hydrocarbons, and ethers.

47. The method according to claim 46, wherein, The petroleum pollutants are selected from at least one of benzene, toluene, ethylbenzene, trimethylbenzene, methyl tert-butyl ether, dichloroethane, trimethylbenzene, and benzo[a]pyrene.

48. The method according to claim 44, wherein, The amount of the slow-release oxygen material added is 0.2-1.2 times the weight of the pollutants contained in the groundwater.

49. The method according to claim 48, wherein, The amount of the slow-release oxygen material added is 0.5-1% of the weight of the pollutants contained in the groundwater.

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