Modified oxygen-releasing nano-peroxide for degrading organic pollutants, preparation method therefor and use thereof, and composite slow-release oxygen material, preparation method therefor and use thereof

Abstract

The present application provides a modified oxygen-releasing nano-peroxide for degrading organic pollutants, a preparation method therefor and a use thereof, and a composite slow-release oxygen material, a preparation method therefor and a use thereof. The modified oxygen-releasing nano-peroxide comprises an oxygen-releasing nano-peroxide, a pH regulator, a polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer, and a cross-linked chitosan membrane layer. The polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer encapsulates the oxygen-releasing nano-peroxide and the pH regulator, and the cross-linked chitosan membrane layer encapsulates the polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer. The modified oxygen-releasing nano-peroxide has high purity and good dispersibility, can maintain stable dissolved oxygen content in water for a relatively long time, and has minimal impact on the environmental pH.

Description

Modified oxygen-releasing nano-peroxides, composite slow-release oxygen materials, preparation methods and applications for degrading organic pollutants Technical Field

[0001] This invention relates to the field of water treatment technology, specifically to a modified oxygen-releasing nano-peroxide for degrading organic pollutants, a composite slow-release oxygen material, its preparation method, and its application. Background Technology

[0002] Groundwater, as a crucial component of the water resource system, plays an irreplaceable role in maintaining the steady progress of the economy and society. However, due to improper disposal of industrial waste and urban garbage, and the overuse of agricultural fertilizers and pesticides, organic pollutants leak into the groundwater system, causing serious problems of organic pollution in groundwater and posing a potential threat to people's production and lives.

[0003] Currently, the main remediation methods for organic pollution in groundwater include extraction treatment, in-situ aeration, in-situ chemical oxidation, and permeable reactive barrier technology. However, these remediation methods generally involve the use of large amounts of chemical agents, large-scale construction, and high operation and maintenance costs. They are often accompanied by the generation of secondary pollutants such as wastewater and exhaust gas, and are prone to tailing or rebound phenomena in the later stages of remediation.

[0004] In recent years, aerobic microbial degradation technology has attracted widespread attention due to its advantages such as low disturbance, low cost, and no secondary pollution. Among these advantages, the dissolved oxygen (DO) level in groundwater is considered a key factor affecting in-situ bioremediation. Because the dissolved oxygen content in groundwater is low, it is difficult to support effective degradation by aerobic microorganisms. Therefore, using solid oxygen-releasing compounds such as calcium peroxide (CaO2) to supply oxygen to groundwater is considered a highly promising oxygen delivery method. However, in practical applications, this method has a significant impact on the environmental pH and the oxygen release rate is too rapid, adversely affecting the microbial growth environment and the organic matter degradation process, thus weakening the expected results of in-situ remediation. Summary of the Invention

[0005] The purpose of this invention is to provide a modified oxygen-releasing nano-peroxide, a composite slow-release oxygen material, a preparation method, and applications for degrading organic pollutants. This aims to at least solve one of the problems in existing technologies where modified nano-peroxides suffer from low purity, poor dispersibility, rapid oxygen release, poor stability, and significant impact on environmental pH. The composite slow-release oxygen material of this invention, based on modified nano-peroxides, further significantly slows down the oxygen release time, increases the dissolved oxygen content in water, and improves the redox potential, enabling stable oxygen release over a long period, enhancing stability, while having almost no effect on pH.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] In a first aspect, a modified oxygen-releasing nano-peroxide for degrading organic pollutants is provided, comprising an oxygen-releasing nano-peroxide, a pH adjuster, a polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer and a cross-linked chitosan membrane layer, wherein the polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer encapsulates the oxygen-releasing nano-peroxide and the pH adjuster, and the cross-linked chitosan membrane layer encapsulates the polyvinyl alcohol-poly(N-isopropylacrylamide) membrane layer.

[0008] In this invention, the modified oxygen-releasing nano-peroxides that degrade organic pollutants can release oxygen more stably, the oxygen release time can be longer, and the pH of the water body and other environments can be well maintained, avoiding significant pH changes caused by oxygen release.

[0009] In one embodiment, the polyvinyl alcohol-poly(N-isopropylacrylamide) film is obtained by polymerizing poly(N-isopropylacrylamide) and polyvinyl alcohol; and / or, the crosslinked chitosan film is obtained by crosslinking chitosan and an aldehyde-containing compound.

[0010] In one embodiment, the modified oxygen-releasing nano-peroxide has a particle size of 10 nm to 500 nm, preferably 50 nm to 100 nm. The median particle size Dv of the modified oxygen-releasing nano-peroxide is... 50 The wavelength range is 50nm to 200nm, preferably 50nm to 100nm.

[0011] In one embodiment, the modified oxygen-releasing nano-peroxide further includes a dispersant and a stabilizer.

[0012] In one embodiment, the oxygen-releasing nano-peroxide includes at least one of nano-calcium peroxide, nano-magnesium peroxide, nano-sodium peroxide, and nano-potassium peroxide, preferably nano-calcium peroxide.

[0013] In one embodiment, the pH adjuster comprises hydrogen phosphate and / or ammonium salt, preferably hydrogen phosphate and ammonium salt. Further, the mass ratio of the hydrogen phosphate to the ammonium salt is 1:(0.1–5), preferably 1:(1–3). Even further, the hydrogen phosphate is selected from potassium dihydrogen phosphate and / or dipotassium hydrogen phosphate, preferably potassium dihydrogen phosphate, and the ammonium salt is selected from ammonium sulfate and / or ammonium chloride, preferably ammonium sulfate.

[0014] In one embodiment, the dispersant comprises at least one selected from polyethylene glycol, sodium dodecyl sulfate, and polyacrylamide, preferably polyethylene glycol. And / or, the stabilizer comprises at least one selected from sodium citrate, citric acid, lactic acid, and sodium lactate, preferably sodium citrate.

[0015] The polyethylene glycol is selected from polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600, with polyethylene glycol 200 being preferred.

[0016] Secondly, a method for preparing the modified oxygen-releasing nano-peroxide for degrading organic pollutants as described in the first aspect is provided, comprising:

[0017] (1) Prepare oxygen-releasing nano-peroxide emulsion A containing pH adjuster and polyvinyl alcohol;

[0018] (2) Chitosan, aldehyde-containing compound, poly(N-isopropylacrylamide) and dilute acid aqueous solution are mixed to obtain solution B;

[0019] (3) Add the solution B to the oxygen-releasing nano-peroxide emulsion A, adjust the pH value to 10-12, preferably 10-11, and carry out the reaction to obtain modified oxygen-releasing nano-peroxide.

[0020] In one embodiment, in step (1), the oxygen-releasing nano-peroxide emulsion A containing pH adjuster and polyvinyl alcohol is prepared by adding hydrogen peroxide dropwise to an aqueous solution containing soluble oxygen-releasing salt, dispersant, stabilizer and ammonia, and then adding pH adjuster and polyvinyl alcohol and mixing.

[0021] In one embodiment, in step (1), the mass ratio of the soluble oxygen-releasing salt, dispersant, stabilizer, ammonia, hydrogen peroxide, pH adjuster, polyvinyl alcohol, and water is: 1:(0.05~0.5):(0.05~0.5):(1~6):(1~10):(0.1~5):(0.01~0.1):(2-10), preferably 1:(0.08~0.5):(0.08~0.5):(1~4):(1~5):(0.8~5):(0.008~0.05):(2-5).

[0022] In one embodiment, in step (1), the rate of adding hydrogen peroxide is 0.05 ml / min to 1 ml / min, preferably 0.1 to 0.5 ml / min.

[0023] In one embodiment, in step (1), the soluble oxygen-releasing salt is at least one selected from soluble calcium salt, soluble magnesium salt, soluble sodium salt, and soluble potassium salt. Further, the soluble calcium salt is selected from at least one selected from calcium chloride, calcium sulfate, calcium bicarbonate, and calcium nitrate, preferably calcium chloride. The soluble magnesium salt is selected from at least one selected from magnesium chloride, magnesium sulfate, magnesium bicarbonate, and magnesium nitrate, preferably magnesium chloride. The soluble sodium salt is selected from at least one selected from sodium chloride, sodium sulfate, sodium bicarbonate, and sodium nitrate, preferably sodium chloride. The soluble potassium salt is selected from at least one selected from potassium chloride, potassium sulfate, potassium bicarbonate, and potassium nitrate, preferably potassium chloride.

[0024] In one embodiment, in step (1), the dispersant is selected from at least one of polyethylene glycol, sodium dodecyl sulfate, and polyacrylamide, preferably polyethylene glycol. The stabilizer is selected from at least one of sodium citrate, citric acid, lactic acid, and sodium lactate, preferably sodium citrate.

[0025] The polyethylene glycol is selected from polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600, with polyethylene glycol 200 being preferred.

[0026] In one embodiment, in step (1), the mass concentration of the ammonia water is 10% to 50%, preferably 10% to 30%.

[0027] In one embodiment, in step (1), the mass concentration of hydrogen peroxide is 10% to 50%, preferably 10% to 30%.

[0028] In one embodiment, in step (1), the pH adjuster is selected from hydrogen phosphate and / or ammonium salt, preferably hydrogen phosphate and ammonium salt. Further, the mass ratio of hydrogen phosphate to ammonium salt is 1:(0.1-5), preferably 1:(1-3). Even further, the hydrogen phosphate is selected from potassium dihydrogen phosphate and / or dipotassium hydrogen phosphate, preferably potassium dihydrogen phosphate, and the ammonium salt is selected from ammonium sulfate and / or ammonium chloride, preferably ammonium sulfate. In this process, the addition of the pH adjuster not only effectively overcomes the problem of pH increase when the slow-release oxygen material comes into contact with water, but also better maintains the pH of the environment, and provides the necessary nitrogen and phosphorus sources for microbial growth, promoting long-term oxygen release.

[0029] In one embodiment, in step (1), the aqueous solution containing the soluble oxygen-releasing salt, dispersant, stabilizer, and ammonia can be prepared using conventional methods in the art. For example, calcium chloride is first added to water and stirred until dissolved, and then the dispersant, stabilizer, and ammonia are added and mixed. Mixing can be carried out using conventional methods in the art, such as stirring.

[0030] In one embodiment, in step (2), the mass ratio of chitosan, aldehyde-containing compound, poly(N-isopropylacrylamide) and dilute acid aqueous solution is (1-5):(0.01-1):(0.01-0.8):100, preferably (1-3):(0.1-0.5):(0.01-0.5):100.

[0031] In one embodiment, in step (2), the aldehyde-containing compound is at least one of formaldehyde, glutaraldehyde, glutaric anhydride, and succinic anhydride, preferably glutaraldehyde.

[0032] In one embodiment, in step (2), the dilute acid aqueous solution is selected from at least one of dilute hydrochloric acid aqueous solution, dilute sulfuric acid aqueous solution, dilute nitric acid aqueous solution, and dilute citric acid aqueous solution. The molar concentration of the dilute acid aqueous solution is 0.1 mol / L to 4 mol / L, preferably 0.1 mol / L to 1.0 mol / L.

[0033] In one embodiment, in step (2), chitosan is first dissolved in a dilute acid aqueous solution, and then an aldehyde-containing compound and poly(N-isopropylacrylamide) are added and mixed.

[0034] In one embodiment, in step (2), the mixing time is 2 min to 20 min, preferably 5 min to 15 min. The mixing method can be stirring, with a stirring rate / rotation speed of 100 rpm / min to 700 rpm / min, preferably 300 rpm / min to 500 rpm / min, and a stirring time of 2 min to 20 min, preferably 5 min to 15 min.

[0035] In one embodiment, the mass ratio of the solution B to the nano peroxide emulsion A is 1:(1-10), preferably 1:(2-8), for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8.

[0036] The specific ratio of raw materials in steps (1) and (2) of the present invention can achieve better effects of modified oxygen-releasing nano-peroxides.

[0037] In one embodiment, in step (3), the solution B is added to the oxygen-releasing nano-peroxide emulsion A by dropwise addition. In this invention, the dropwise addition method is more conducive to the release of oxygen and maintenance of pH value of the prepared modified oxygen-releasing nano-peroxide. Furthermore, the dropwise addition rate is 0.05–1 ml / min, preferably 0.1–0.9 ml / min. Controlling the dropwise addition rate within a specific range is more conducive to improving the effect.

[0038] In one embodiment, in step (3), a dilute alkaline aqueous solution is used to adjust the pH value. Preferably, the pH value is adjusted by dripping, for example, at a rate of 0.1-1.5 mL / min. Further, the dilute alkaline aqueous solution is selected from at least one of dilute sodium hydroxide aqueous solution, dilute potassium hydroxide aqueous solution, and ammonia aqueous solution. The mass concentration of the dilute alkaline aqueous solution is 0.1 g / L to 10 g / L, preferably 2 g / L to 5 g / L.

[0039] In one embodiment, in step (3), the reaction time is 1 to 30 minutes, preferably 3 to 10 minutes.

[0040] In one embodiment, in step (3), before obtaining the modified oxygen-releasing nano-peroxide after the reaction, solid-liquid separation, washing, and drying are performed. The solid-liquid separation can be carried out using conventional methods in the art, such as centrifugation or filtration, with centrifugation being preferred. Further, the centrifugation conditions are a centrifugation speed of 4000–6000 rpm / min and a centrifugation time of 2–10 min, preferably a centrifugation speed of 5000 rpm / min and a centrifugation time of 5 min. The washing can be performed by repeated rinsing with deionized water and / or an organic solvent, preferably rinsing first with deionized water and then with an organic solvent. More preferably, rinsing with deionized water 2–3 times and with an organic solvent 2–3 times. The organic solvent is selected from one or more of ethanol, acetone, diethyl ether, and petroleum ether, with ethanol being preferred. The inventors have found that this washing method can improve the dispersion performance of the modified oxygen-releasing nano-peroxide.

[0041] In one embodiment, in step (3), the drying temperature is 30-80°C, preferably 40-60°C, and the drying time is 4h-24h, preferably 8h-12h.

[0042] Thirdly, a composite slow-release oxygen material is provided, comprising a modified oxygen-releasing nano-peroxide and a modified sodium alginate coating layer, wherein the modified sodium alginate coating layer encapsulates at least a portion of the modified oxygen-releasing nano-peroxide, wherein the modified oxygen-releasing nano-peroxide is the modified oxygen-releasing nano-peroxide described in the first aspect and / or the modified oxygen-releasing nano-peroxide prepared by the method described in the second aspect.

[0043] The sodium alginate coating layer is obtained by crosslinking modified sodium alginate and soluble calcium salt.

[0044] In one embodiment, the modified sodium alginate is modified with 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA).

[0045] Fourthly, a method for preparing the composite slow-release oxygen material described in the third aspect is provided, comprising filling a modified oxygen-releasing nano-peroxide into a cylindrical device with a grid, then sequentially impregnating it in an aqueous solution of modified sodium alginate and in an aqueous solution of a soluble calcium salt, and drying it to obtain the composite slow-release oxygen material, wherein the modified oxygen-releasing nano-peroxide is the modified oxygen-releasing nano-peroxide described in the first aspect and / or the modified oxygen-releasing nano-peroxide prepared by the method described in the second aspect.

[0046] In one embodiment, a grid is provided on the outer peripheral surface of the cylindrical device, and a suitable filter bag is built into the cylindrical device.

[0047] In one embodiment, the grid is composed of grid bars arranged in a uniformly staggered pattern. Preferably, the grid is composed of parallel grid bars arranged in a staggered pattern. More preferably, the included angle α between the staggered grid bars is 0–90°, preferably 30–90°; the spacing L between adjacent grid bars is 0.5–3 cm, preferably 1–2 cm; and the width of the grid bars is 0.1–0.5 cm, preferably 0.1–0.2 cm. When the grid parameters are within the above preferred ranges, the prepared composite slow-release oxidizing material for degrading organic pollutants can more effectively slow down oxygen release, increase dissolved oxygen and redox potential in water, and exhibit better stability.

[0048] In one embodiment, the cylindrical device is cylindrical, and the diameter-to-height ratio D / H of the cylindrical device is 0.1 to 0.5, preferably 0.1 to 0.3. The diameter-to-height ratio refers to the ratio between the diameter and height of the cylindrical device. Preferably, the diameter D of the cylindrical device is 1 to 10 cm, more preferably 3 to 6 cm, and the height H of the cylindrical device is 1 to 100 cm, more preferably 20 to 50 cm.

[0049] In one embodiment, the two ends of the cylindrical device with the grille are open.

[0050] In one embodiment, the top of the outer peripheral surface has an external thread, and the bottom of the outer peripheral surface has an internal thread. Multiple gridded cylindrical devices can be connected by threads. For example, the top of gridded cylindrical device A and the bottom of gridded cylindrical device B are connected by threads, the top of gridded cylindrical device B and the bottom of gridded cylindrical device C are connected by threads, and so on, with no limitation on the number of connections.

[0051] In one embodiment, the grid strip can be a metal wire, and more preferably, the metal wire can be at least one of stainless steel wire, iron wire, copper wire, aluminum wire, titanium wire, etc., with stainless steel wire being preferred.

[0052] In one embodiment, the filter bag has a mesh size of 50 to 500 mesh, preferably 100 to 300 mesh.

[0053] In one embodiment, the adaptation may refer to the shape and size of the filter bag and the shape and size of the cylindrical device with grid not differing by more than ±0.5 cm.

[0054] In one embodiment, the filter bag can be made of polyester fiber, polypropylene, nylon, glass fiber, etc. The filter bag can be sealed with a drawstring.

[0055] In one embodiment, the first immersion temperature is room temperature, and the first immersion time is 1–120 min, preferably 10 min–60 min. The second immersion temperature is room temperature, and the second immersion time is 1–120 min, preferably 10 min–60 min. The methods of the first and second immersion are not specifically limited, as long as the cylindrical device with the grid is completely immersed in the sodium alginate aqueous solution and / or the soluble calcium salt aqueous solution.

[0056] In one embodiment, the mass concentration of the modified sodium alginate aqueous solution is 1 g / L to 50 g / L, preferably 5 g / L to 30 g / L. The mass concentration of the soluble calcium salt aqueous solution is 1 g / L to 50 g / L, preferably 5 g / L to 40 g / L.

[0057] In one embodiment, the method for preparing the modified sodium alginate includes: stirring 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), sulfuric acid, sodium alginate and water in a water bath at 80°C to 150°C for 2 to 8 hours.

[0058] In one embodiment, the mass ratio of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), sulfuric acid, sodium alginate and water is 1:(0.01-1.5):(1-5):(10-500), preferably 1:(0.05-1):(1-3):(50-200).

[0059] In one embodiment, the molar concentration of the sulfuric acid is 1 to 5 mol / L, preferably 2 to 4 mol / L.

[0060] In one embodiment, the soluble calcium salt is selected from at least one of calcium chloride, calcium sulfate, and calcium bicarbonate, preferably calcium chloride.

[0061] In one embodiment, the drying temperature is 20–60°C, preferably 30–40°C, and the drying time is 4–24 hours, preferably 8–12 hours. Alternatively, air drying can be used, with ventilation, at a temperature of 20–35°C, for 4–24 hours, preferably 30–35°C, for 8–12 hours.

[0062] In this invention, reactions not mentioned can be carried out at room temperature.

[0063] In this invention, the room temperature is 20–35°C, preferably 20–30°C.

[0064] Fifthly, a cylindrical device with a grid is provided, which is applied to the preparation method of the composite slow-release oxygen material described in the fourth aspect, characterized in that a grid is provided on the outer peripheral surface of the cylindrical device, and a suitable filter bag is built into the cylindrical device.

[0065] In one embodiment, a grid is provided on the outer peripheral surface of the cylindrical device, and a suitable filter bag is built into the cylindrical device.

[0066] In one embodiment, the grid is composed of grid bars arranged in a uniformly staggered pattern. Preferably, the grid is composed of parallel grid bars arranged in a staggered pattern. More preferably, the included angle α between the staggered grid bars is 0–90°, preferably 30–90°; the spacing L between adjacent grid bars is 0.5–3 cm, preferably 1–2 cm; and the width of the grid bars is 0.1–0.5 cm, preferably 0.1–0.2 cm. When the grid parameters are within the above preferred ranges, the prepared composite slow-release oxidizing material for degrading organic pollutants can more effectively slow down oxygen release, increase dissolved oxygen and redox potential in water, and exhibit better stability.

[0067] In one embodiment, the cylindrical device is cylindrical, and the diameter-to-height ratio D / H of the cylindrical device is 0.1 to 0.5, preferably 0.1 to 0.3. The diameter-to-height ratio refers to the ratio between the diameter and height of the cylindrical device. Preferably, the diameter D of the cylindrical device is 1 to 10 cm, more preferably 3 to 6 cm, and the height H of the cylindrical device is 1 to 100 cm, more preferably 20 to 50 cm.

[0068] In one embodiment, the two ends of the cylindrical device with the grille are open.

[0069] In one embodiment, the top of the outer peripheral surface has an external thread, and the bottom of the outer peripheral surface has an internal thread. Multiple gridded cylindrical devices can be connected by threads. For example, the top of gridded cylindrical device A and the bottom of gridded cylindrical device B are connected by threads, the top of gridded cylindrical device B and the bottom of gridded cylindrical device C are connected by threads, and so on, with no limitation on the number of connections.

[0070] In one embodiment, the grid strip can be a metal wire, and more preferably, the metal wire can be at least one of stainless steel wire, iron wire, copper wire, aluminum wire, titanium wire, etc., with stainless steel wire being preferred.

[0071] In one embodiment, the filter bag has a mesh size of 50 to 500 mesh, preferably 100 to 300 mesh.

[0072] In one embodiment, the adaptation may refer to the shape and size of the filter bag and the shape and size of the cylindrical device with grid not differing by more than ±0.5 cm.

[0073] In one embodiment, the filter bag can be made of polyester fiber, polypropylene, nylon, glass fiber, etc. The filter bag can be sealed with a drawstring.

[0074] Sixthly, the application of the modified oxygen-releasing nano-peroxides and / or composite slow-release oxygen materials for degrading organic pollutants in the remediation of soil and / or groundwater containing organic pollutants is provided.

[0075] In one embodiment, the organic pollutant includes at least one of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, and benzene compounds.

[0076] Compared with the prior art, the beneficial effects of this application are:

[0077] (1) In this invention, both the oxygen-releasing nano-peroxide and the pH adjuster are encapsulated, and are respectively encapsulated by a polyvinyl alcohol-poly(N-isopropylacrylamide) film layer and a cross-linked chitosan film layer, forming a modified oxygen-releasing nano-peroxide with a double-layer encapsulation of specific film layers. The oxygen-releasing nano-peroxide, the pH adjuster, and the specific film layers achieve a synergistic effect, significantly increasing the stability of the modified oxygen-releasing nano-peroxide, allowing oxygen to be released for a longer period of time, and better maintaining the pH of the environment. Moreover, the oxygen-releasing nano-peroxide of this invention also reaches the nanoscale in the cross-linked state, with a particle size of about 10 nm to 500 nm and a median particle size Dv50 of 50 nm to 200 nm.

[0078] (2) In step 1 of this invention, metal salt, dispersant, hydrogen peroxide, ammonia, stabilizer, polymer 1, and pH adjuster are used to form emulsion A. In step 2, chitosan, crosslinking agent, and polymer 2 are used to form solution B. In step 3, solution B is dropped into solution A to form modified nano-calcium peroxide. When solution B is dropped into A, polymer A and polymer B will form a layer of polyvinyl alcohol-poly(N-isopropylacrylamide) film, which will encapsulate the oxygen-releasing nano-peroxide and pH adjuster. When alkali solution is added, chitosan and crosslinking agent will form a second layer of crosslinked chitosan film. The modified oxygen-releasing nano-peroxide prepared according to the method of this invention has a large coating amount, high calcium peroxide purity, good dispersibility, and prolongs the slow release time. The addition of pH adjuster not only overcomes the problem of pH increase when the slow-release oxygen material is exposed to water, but also provides the nitrogen and phosphorus sources required for microbial growth. It also has the functions of long-term oxygen release and pH adjustment.

[0079] (3) Modified nano-peroxides are loaded into filter bags, then filled into the cylindrical device with a grid of the present invention. The modified nano-peroxides are then soaked three times to form a special three-layer coating. This device is placed in the monitoring well as an oxygen source well, which not only significantly slows down the oxygen release time but also increases the dissolved oxygen content and redox potential in the groundwater, resulting in better stability. In addition, the use of hydrophobic modified sodium alginate reduces the solubility of the coating in water and prolongs the action time of the three-layer coating in water.

[0080] (4) The cylindrical device with grid grid of the present invention is suitable for most soil-groundwater monitoring wells (e.g., 6.3 cm in diameter), and can also be modularly filled. It has the advantages of simple operation and easy promotion. Attached Figure Description

[0081] Figure 1 is a SEM image of the modified nano-calcium peroxide proposed in Example 1 of this application;

[0082] Figure 2 is a SEM image of commercially available calcium peroxide proposed in Comparative Example 4 of this application;

[0083] Figure 3 is a TEM image of the modified nano-calcium peroxide proposed in Example 1 of this application;

[0084] Figure 4 is a TEM image of commercially available calcium peroxide proposed in Comparative Example 4 of this application;

[0085] Figure 5 shows the XRD patterns of the modified nano-calcium peroxide proposed in Example 1 and the calcium peroxide proposed in Comparative Example 4. In the figure, CaO2 refers to the calcium peroxide of Comparative Example 4, and pH / CS / Nano-CaO2 refers to the modified nano-calcium peroxide obtained in Example 1.

[0086] Figure 6 is a structural schematic diagram of the cylindrical device with a grid proposed in Embodiment 4 of this application;

[0087] Figure 7 is a schematic diagram of the filling of the modified nano-calcium peroxide proposed in Example 4 of this application;

[0088] The reference numerals in Figures 6 and 7 are as follows: 1-outer peripheral surface; 11-grid; 12-external thread; 111-grid bar; 2-filter bag; 21-drawstring;

[0089] Figure 8 shows the curves of dissolved oxygen content in water as a function of time for the composite slow-release oxygen materials proposed in Examples 4-6 and Comparative Examples 5-9 of this application.

[0090] Figure 9 shows the pH change curves of the composite slow-release oxygen materials proposed in Examples 4-6 and Comparative Examples 5-9 of this application in water bodies over time.

[0091] Figure 10 shows the redox potential of the composite slow-release oxygen materials proposed in Examples 4-6 and Comparative Examples 5-9 of this application as a function of time in water. Detailed Implementation

[0092] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0093] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional steps or conditions described in the literature in this field.

[0094] Unless otherwise stated, all reagents and raw materials used in the examples are commercially available products.

[0095] The filter bags were purchased from Zhongting Environmental Protection, model NMOZT-200 mesh-50*1000.

[0096] In this invention, the morphology and particle size of the samples were observed using a Japanese JEOL-7800 field emission scanning electron microscope (SEM).

[0097] In this invention, a Japanese JEM-2100F transmission electron microscope (TEM) was used to observe the morphology and dispersion of the samples.

[0098] In this invention, a German Bruker D8 X-ray diffractometer (XRD) was used to identify the composition and structure of the samples. The test conditions were: CuKα radiation, Ni filter, tube voltage 40 kV, tube current 40 mA, and scan rate 2° / min.

[0099] It should be noted that in the description of this application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0100] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0101] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0102] As shown in Figures 6-7, this embodiment provides a cylindrical device with a grid. The outer peripheral surface 1 of the cylindrical device is provided with a grid 11, and the cylindrical device has a fitted filter bag 2 inside.

[0103] Further, the grid 11 is composed of grid bars 111 arranged in a uniformly staggered pattern. Preferably, the grid 11 is composed of parallel grid bars 111 arranged in a staggered pattern. More preferably, the included angle α between the staggered grid bars 111 of the grid 11 is 0–90°, preferably 30–90°; the spacing L between adjacent grid bars 111 is 0.5–2 cm, preferably 1–2 cm; and the width of the grid bars 111 is 0.1–0.5 cm, preferably 0.1–0.2 cm. When the parameters of the grid 11 are within the preferred range, the prepared composite slow-release oxidant for degrading organic pollutants can more effectively slow down oxygen release, increase dissolved oxygen and redox potential in the water, and exhibit better stability.

[0104] Further, the cylindrical device is cylindrical, and the diameter-to-height ratio D / H of the cylindrical device is 0.1 to 0.5, preferably 0.1 to 0.3. The diameter-to-height ratio refers to the ratio between the diameter and the height of the cylindrical device. Preferably, the diameter D of the cylindrical device is 1 to 10 cm, more preferably 3 to 6 cm, and the height H of the side is 1 to 100 cm, more preferably 20 to 50 cm.

[0105] Furthermore, the two ends of the cylindrical device with the grid are open.

[0106] Furthermore, the top of the outer peripheral surface 1 has an external thread 12, and the bottom of the outer peripheral surface 1 has an internal thread. Multiple of the gridded cylindrical devices can be connected by threads. For example, the top of gridded cylindrical device A and the bottom of gridded cylindrical device B are connected by threads, the top of gridded cylindrical device B and the bottom of gridded cylindrical device C are connected by threads, and so on, with no limitation on the number of connections.

[0107] Furthermore, the grid strip 111 is a metal wire, which can be at least one of stainless steel wire, iron wire, copper wire, aluminum wire, titanium wire, etc., preferably stainless steel wire.

[0108] Furthermore, the mesh size of the filter bag is 50 to 500 mesh, preferably 100 to 300 mesh.

[0109] Furthermore, the adaptation may refer to the fact that the shape and size of the filter bag and the shape and size of the cylindrical device with grid differ by no more than ±0.5cm.

[0110] Furthermore, the filter bag is made of materials such as polyester fiber, polypropylene, nylon, and glass fiber. The filter bag can be sealed with a drawstring.

[0111] Example 1

[0112] This embodiment provides a modified oxygen-releasing nano-peroxide for degrading organic pollutants, and the preparation method is as follows:

[0113] (1) Add 11.1g of calcium chloride to 25g of deionized water and stir until dissolved. Then add 1g of dispersant polyethylene glycol 200, 1g of stabilizer sodium citrate and 35g of concentrated ammonia with a mass concentration of 30% and stir until dissolved. Then add 50g of hydrogen peroxide with a mass concentration of 30% dropwise to the above solution at 0.2mL / min to carry out the reaction. After the dropwise addition is completed, add 10g of pH adjuster (5g of potassium dihydrogen phosphate and 5g of ammonium sulfate) and 0.1g of polyvinyl alcohol and stir until dissolved to form emulsion A.

[0114] (2) Add 0.5g of chitosan to 50g of hydrochloric acid with a molar concentration of 1.0mol / L, stir to dissolve, then add 0.1g of glutaraldehyde and 0.1g of poly(N-isopropylacrylamide), and stir at 300rppm / min for 10min to form solution B.

[0115] (3) Solution B was added dropwise to emulsion A at 0.2 mL / min to form solution C. Sodium hydroxide solution with a mass concentration of 2 g / L was added dropwise to solution C at 0.5 mL / min until the pH of solution C was adjusted to 10. The reaction was carried out for 5 min, and then centrifuged at 5000 rpm / min for 5 min to obtain a solid mixture. The obtained solid mixture was washed twice with deionized water and then twice with ethanol. It was dried at 60℃ for 8 h to obtain modified nano calcium peroxide.

[0116] The morphology and particle size of the modified nano-calcium peroxide in this embodiment were observed using a JEOL-7800 field emission scanning electron microscope (SEM), as shown in Figure 1.

[0117] The morphology and dispersibility of the modified nano-calcium peroxide in this embodiment were observed using a JEM-2100F transmission electron microscope (TEM) from Japan, as shown in Figure 3.

[0118] The composition and structure of the modified nano-calcium peroxide in this embodiment were observed using a German Bruker D8 X-ray diffractometer (XRD), as shown in Figure 4.

[0119] Example 2

[0120] This embodiment provides a modified oxygen-releasing nano-peroxide for degrading organic pollutants, and the preparation method is as follows:

[0121] (1) Add 11.1g of calcium chloride to 25g of deionized water and stir until dissolved. Then add 5g of dispersant polyethylene glycol 200, 1g of stabilizer sodium citrate and 35g of concentrated ammonia with a mass concentration of 30% and stir until dissolved. Then add 50g of hydrogen peroxide with a mass concentration of 30% dropwise to the solution at 0.2mL / min to carry out the reaction. After the dropwise addition is completed, add 20g of pH adjuster (10g of potassium dihydrogen phosphate and 10g of ammonium sulfate) and 0.2g of polyvinyl alcohol and stir until dissolved to form emulsion A.

[0122] (2) Add 1g of chitosan to 50g of hydrochloric acid with a molar concentration of 1.0mol / L, stir to dissolve, then add 0.2g of glutaraldehyde and 0.2g of poly(N-isopropylacrylamide), and stir at 300rppm for 10min to form solution B.

[0123] (3) Solution B was added dropwise to emulsion A at 0.2 mL / min to form solution C. Sodium hydroxide solution with a mass concentration of 2 g / L was added dropwise to solution C at 0.5 mL / min until the pH of solution C was adjusted to 11. The reaction was carried out for 3 min. Then, the mixture was centrifuged at 5000 rpm / min for 5 min to obtain a solid mixture. The solid mixture was washed twice with deionized water and then twice with ethanol. It was dried at 60℃ for 8 h to obtain modified nano calcium peroxide.

[0124] Example 3

[0125] Same as Example 1, except that the amount of glutaraldehyde added in step (2) is 0.5g.

[0126] Comparative Example 1

[0127] Same as Example 1, except that glutaraldehyde is not added in step (2).

[0128] Comparative Example 2

[0129] Same as in Example 1, except that in step (3), solution B is added dropwise to emulsion A at a rate of 5 mL / min to form solution C.

[0130] Comparative Example 3

[0131] Same as Example 1, except that polyvinyl alcohol is not added in step (1) and poly(N-isopropylacrylamide) is not added in step (2).

[0132] Comparative Example 4

[0133] Commercially available calcium peroxide (purchased from Foshan Nongxin Biotechnology Co., Ltd.) contains 50-60% calcium peroxide.

[0134] The morphology and particle size of this calcium peroxide were observed using a Japanese JEOL-7800 field emission scanning electron microscope (SEM), as shown in Figure 2.

[0135] The morphology and dispersibility of this calcium peroxide were observed using a JEM-2100F transmission electron microscope (TEM) from Japan, as shown in Figure 4.

[0136] The composition and structure of this calcium peroxide were observed using a German Bruker D8 X-ray diffractometer (XRD), as shown in Figure 5.

[0137] Test Example 1

[0138] The calcium peroxide content of the products prepared in the examples and comparative examples was measured according to the potassium permanganate titration method in the standard HG / T 4505-2013 "Industrial Calcium Peroxide". The measurement results are shown in Table 1.

[0139] Table 1. Calcium peroxide content

[0140] Application Example 1

[0141] Prepare 500 mL of 0.3 g / L sodium sulfite solution with an initial dissolved oxygen content of 0.05 mg / L and a pH of 7.42. Use 2 g of samples from Examples 1-3 and Comparative Examples 1-4 to conduct column experiments for 1 day at a flow rate of 1 mL / min. The dissolved oxygen content and pH value after 1 day are shown in Table 2.

[0142] Table 2 Dissolved oxygen content and pH

[0143] Example 4

[0144] This embodiment provides a composite slow-release oxygen material for degrading organic pollutants, and the preparation method is as follows:

[0145] Modified sodium alginate was prepared by stirring in a water bath at 100°C for 2 hours with 1 g of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), 1 g of sulfuric acid with a molar concentration of 4 mol / L, 2 g of sodium alginate, and 50 g of deionized water. Following steps (1)-(3) of Example 1, 1 kg of modified nano-calcium peroxide was prepared. 1 kg of modified nano-calcium peroxide was placed in an NMOZT-200 mesh-50*1000 filter bag, which was then placed in a cylindrical device with a grid. The filter bag was then placed in a 10 g / L modified sodium alginate aqueous solution, ensuring the solution submerged the gridded cylindrical device. After soaking at room temperature for 30 minutes, the filter bag was removed and placed in a 10 g / L CaCl2 aqueous solution, again submerging the gridded cylindrical device. The filter bag was soaked at room temperature for 30 minutes and then air-dried at 30°C for 8 hours to obtain a composite slow-release oxygen material for degrading organic pollutants.

[0146] As shown in Figure 6, the cylindrical device with a grid has two through ends, and a grid 11 is provided on the outer peripheral surface 1 of the cylindrical device. The grid 11 is composed of uniformly parallel grid bars 111 arranged in an alternating pattern, and the grid bars 111 are stainless steel wires. The included angle α between the alternating stainless steel wires 111 of the grid 11 is 90°, the spacing L between adjacent stainless steel wires 111 is 1cm, and the diameter of the stainless steel wires 111 is 0.1cm. The cylindrical device is cylindrical, the diameter D of the cylindrical device is 5cm, and the height H of the cylindrical device is 20cm. The top of the outer peripheral surface 1 has an external thread 12, and the bottom of the outer peripheral surface 1 has an internal thread.

[0147] In this embodiment, modified nano-calcium peroxide is uniformly filled into a filter bag, and the filter bag is filled into five cylindrical devices with grids (as shown in Figure 7). These five cylindrical devices with grids can be connected end to end (i.e., the top surface of the first cylindrical device and the bottom surface of the second cylindrical device are connected together by threads, the top surface of the second cylindrical device and the bottom surface of the third cylindrical device are connected together by threads, and so on).

[0148] Example 5

[0149] This embodiment provides a composite slow-release oxygen material for degrading organic pollutants, and the preparation method is as follows:

[0150] Similar to Example 4, except that the material was placed in a 30 g / L modified sodium alginate aqueous solution, ensuring the sodium alginate aqueous solution completely covered the cylindrical device with a grid. After soaking at room temperature for 60 minutes, the material was removed and placed in a 40 g / L CaCl2 aqueous solution, ensuring the CaCl2 aqueous solution completely covered the cylindrical device with a grid. After soaking at room temperature for 60 minutes, the material was air-dried at 30°C for 12 hours to obtain a composite slow-release oxygen material for degrading organic pollutants.

[0151] Example 6

[0152] Same as in Example 4, except that the spacing L between the stainless steel wires 111 is 3cm.

[0153] Comparative Example 5

[0154] Similar to Example 4, except that 1 kg of the prepared modified nano-calcium peroxide was placed in an NMOZT-200 mesh-50*1000 filter bag instead of a cylindrical device with a grid. Instead, it was directly placed in a 10 g / L modified sodium alginate aqueous solution, ensuring the modified sodium alginate solution completely submerged the filter bag. After soaking at room temperature for 30 min, it was removed and placed in a 10 g / L CaCl2 aqueous solution, ensuring the CaCl2 solution completely submerged the filter bag. It was then soaked at room temperature for 30 min and air-dried at 30°C for 8 h to obtain a composite slow-release oxygen material, nano-calcium peroxide, for degrading organic pollutants.

[0155] Comparative Example 6

[0156] Similar to Example 4, except that the 1 kg of modified nano-calcium peroxide prepared was not filled into a filter bag or a cylindrical device with a grid, but was directly placed into a 10 g / L modified sodium alginate aqueous solution. After stirring at room temperature for 30 min, it was taken out and dripped into a 10 g / L CaCl2 aqueous solution, stirred for 30 min, and dried at 30°C for 8 h to obtain a composite slow-release oxygen material for degrading organic pollutants.

[0157] Comparative Example 7

[0158] Similar to Example 4, except that the filter bag is filled with modified oxygen-releasing nano-peroxide prepared according to Comparative Example 1.

[0159] Comparative Example 8

[0160] Same as Example 4, except that paraffin is used instead of modified sodium alginate as the coating solution.

[0161] Comparative Example 9

[0162] Similar to Example 4, except that the filter bag is filled with commercially available calcium peroxide as in Comparative Example 4, and no further processing is performed after it is placed in the cylindrical device.

[0163] Application Example 2

[0164] The composite slow-release oxygen materials (1 kg composite slow-release oxygen material with a cylindrical device) obtained in Examples 4-6 and Comparative Examples 7-9, the composite slow-release oxygen material (1 kg composite slow-release oxygen material with a filter bag) obtained in Comparative Example 5, and the composite slow-release oxygen material (1 kg composite slow-release oxygen material filled into the cylindrical device described in Example 4) obtained in Comparative Example 6 were placed in groundwater monitoring wells. The dissolved oxygen (DO), oxidation-reduction potential (ORP), and pH value in the wells were measured at different times. The changes of the relevant parameters over time are shown in Figures 8-10.

[0165] Dissolved oxygen (DO), oxidation-reduction potential (ORP), and pH were measured using a Eureka Easy Probe EP20 five-parameter water quality analyzer from the United States.

[0166] As can be seen from Figures 8-10, the composite slow-release oxygen material prepared by the comparative method begins to fail in a short time after being put into use, and basically stops releasing oxygen; the composite slow-release oxygen material for degrading organic pollutants prepared by the method of the present invention can maintain the dissolved oxygen content in groundwater at 2 mg / L for a long time, up to 180 days, which significantly improves the stability of the composite slow-release oxygen material.

[0167] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A modified oxygen-releasing nano-peroxide for degrading organic pollutants, characterized in that, It includes oxygen-releasing nano-peroxide, a pH adjuster, a polyvinyl alcohol-poly(N-isopropylacrylamide) film layer, and a cross-linked chitosan film layer. The polyvinyl alcohol-poly(N-isopropylacrylamide) film layer encapsulates the oxygen-releasing nano-peroxide and the pH adjuster, and the cross-linked chitosan film layer encapsulates the polyvinyl alcohol-poly(N-isopropylacrylamide) film layer.

2. The modified oxygen-releasing nano-peroxide as described in claim 1, characterized in that, The polyvinyl alcohol-poly(N-isopropylacrylamide) film is obtained by polymerizing poly(N-isopropylacrylamide) and polyvinyl alcohol; and / or, the crosslinked chitosan film is obtained by crosslinking chitosan and an aldehyde-containing compound; And / or, the modified oxygen-releasing nano-peroxide has a particle size of 10 nm to 500 nm, preferably 50 nm to 100 nm; and / or, the median particle size Dv of the modified oxygen-releasing nano-peroxide is... 50 The wavelength range is 50nm to 200nm, preferably 50nm to 100nm; And / or, the oxygen-releasing nano-peroxide includes at least one of nano-calcium peroxide, nano-magnesium peroxide, nano-sodium peroxide, and nano-potassium peroxide, preferably nano-calcium peroxide; And / or, the pH adjuster comprises hydrogen phosphate and / or ammonium salt, preferably hydrogen phosphate and ammonium salt, and further, the mass ratio of the hydrogen phosphate and ammonium salt is 1:(0.1-5), preferably 1:(1-3); And / or, the modified oxygen-releasing nano-peroxide also includes a dispersant and a stabilizer.

3. A method for preparing modified oxygen-releasing nano-peroxides for degrading organic pollutants, comprising: (1) Prepare oxygen-releasing nano-peroxide emulsion A containing pH adjuster and polyvinyl alcohol; (2) Chitosan, aldehyde-containing compound, poly(N-isopropylacrylamide) and dilute acid aqueous solution are mixed to obtain solution B; (3) Add the solution B to the oxygen-releasing nano-peroxide emulsion A, adjust the pH value to 10-12, preferably 10-11, and carry out the reaction to obtain modified oxygen-releasing nano-peroxide.

4. The method for preparing modified oxygen-releasing nano-peroxides as described in claim 3, characterized in that, In step (1), the oxygen-releasing nano-peroxide emulsion A containing pH adjuster and polyvinyl alcohol is prepared by adding hydrogen peroxide dropwise to an aqueous solution containing soluble oxygen-releasing salt, dispersant, stabilizer and ammonia, and then adding pH adjuster and polyvinyl alcohol and mixing. Preferably, the mass ratio of the soluble oxygen-releasing salt, dispersant, stabilizer, ammonia, hydrogen peroxide, pH adjuster, polyvinyl alcohol, and water is 1:(0.05~0.5):(0.05~0.5):(1~6):(1~10):(0.1~5):(0.01~0.1):(2-10), more preferably 1:(0.08~0.5):(0.08~0.5):(1~4):(1~5):(0.8~5):(0.008~0.05):(2-5); And / or, in step (1), the rate of adding hydrogen peroxide is 0.05 ml / min to 1 ml / min, preferably 0.1 to 0.5 ml / min. And / or, in step (1), the pH adjuster is selected from hydrogen phosphate and / or ammonium salt, preferably hydrogen phosphate and ammonium salt; further, the mass ratio of hydrogen phosphate and ammonium salt is 1:(0.1-5), preferably 1:(1-3).

5. The method for preparing the modified oxygen-releasing nano-peroxide as described in claim 3, characterized in that, In step (2), the mass ratio of chitosan, aldehyde-containing compound, poly(N-isopropylacrylamide), and dilute acid aqueous solution is (1-5):(0.01-1):(0.01-0.8):100, preferably (1-3):(0.1-0.5):(0.01-0.5):100; And / or, the aldehyde-containing compound is at least one of formaldehyde, glutaraldehyde, glutaric anhydride, and succinic anhydride, preferably glutaraldehyde; And / or, the mixing time is 2 min to 20 min, preferably 5 min to 15 min. And / or, the mass ratio of the solution B to the nano peroxide emulsion A is 1:(1-10), preferably 1:(2-8).

6. The method for preparing modified oxygen-releasing nano-peroxides as described in claim 3, characterized in that, In step (3), the solution B is added to the oxygen-releasing nano-peroxide emulsion A by dripping. Preferably, the dripping rate is 0.05 to 1 ml / min, and more preferably 0.1 to 0.9 ml / min. And / or, in step (3), the reaction time is 1 to 30 min, preferably 3 to 10 min. And / or, in step (3), after the reaction and before obtaining the modified oxygen-releasing nano-peroxide, solid-liquid separation, washing, and drying are required. The washing is performed by repeatedly rinsing with deionized water and / or organic solvent, preferably by rinsing with deionized water first and then with organic solvent.

7. A composite slow-release oxygen material, comprising a modified oxygen-releasing nano-peroxide and a modified sodium alginate coating layer, wherein the modified sodium alginate coating layer encapsulates at least a portion of the modified oxygen-releasing nano-peroxide, wherein the modified oxygen-releasing nano-peroxide is the modified oxygen-releasing nano-peroxide according to any one of claims 1 to 3 and / or the modified oxygen-releasing nano-peroxide prepared by the method according to any one of claims 4 to 6. Preferably, the sodium alginate coating layer is obtained by crosslinking modified sodium alginate and soluble calcium salt.

8. A method for preparing a composite slow-release oxygen material, comprising filling a modified oxygen-releasing nano-peroxide into a cylindrical device with a grid and an internal filter bag, then sequentially impregnating it in an aqueous solution of modified sodium alginate and in an aqueous solution of a soluble calcium salt, and drying it to obtain the composite slow-release oxygen material, wherein the modified oxygen-releasing nano-peroxide is the modified oxygen-releasing nano-peroxide according to any one of claims 1 to 3 and / or the modified oxygen-releasing nano-peroxide prepared by the method according to any one of claims 4 to 6.

9. The method for preparing the composite slow-release oxygen material as described in claim 8, characterized in that, A grid is provided on the outer circumferential surface of the cylindrical device, and a suitable filter bag is built into the cylindrical device; Preferably, the grille is composed of grille bars that are evenly and alternately arranged; More preferably, the grille is composed of parallel grille bars arranged in an alternating pattern; More preferably, the included angle α between the staggered grid bars of the grid is 0 to 90°, preferably 30 to 90°; the spacing L between adjacent grid bars is 0.5 to 3 cm, preferably 1 to 2 cm; and the width of the grid bars is 0.1 to 0.5 cm, preferably 0.1 to 0.2 cm. Preferably, the diameter-to-height ratio D / H of the cylindrical device is 0.1 to 0.5, more preferably 0.1 to 0.3; Preferably, the two ends of the cylindrical device with the grille are open; Preferably, the top of the outer peripheral curved surface has an external thread, and the bottom of the outer peripheral curved surface has an internal thread, and the plurality of the grid-equipped cylindrical devices can be connected by threads; Preferably, the grid strip is a metal wire, and more preferably, the metal wire is at least one of stainless steel wire, iron wire, copper wire, aluminum wire, titanium wire, etc., with stainless steel wire being the most preferred; And / or, the mesh size of the filter bag is 50 mesh to 500 mesh, preferably 100 mesh to 300 mesh; And / or, the first immersion temperature is room temperature, the first immersion time is 1 to 120 min, preferably 10 min to 60 min; the second immersion temperature is room temperature, the second immersion time is 1 to 120 min, preferably 10 min to 60 min; And / or, the mass concentration of the modified sodium alginate aqueous solution is 1 g / L to 50 g / L, preferably 5 g / L to 30 g / L; and / or, the mass concentration of the soluble calcium salt aqueous solution is 1 g / L to 50 g / L, preferably 5 g / L to 40 g / L.

10. A cylindrical device with a grid, applied to the preparation method of the composite slow-release oxygen material as described in claim 8 or 9, characterized in that, A grid is provided on the outer circumferential surface of the cylindrical device, and a suitable filter bag is built into the cylindrical device; Preferably, the grille is composed of metal wire mesh strips arranged in a uniformly interlaced pattern; More preferably, the grille is composed of parallel grille bars of metal wire arranged in an interlaced pattern; More preferably, the included angle α between the staggered metal wire grid strips of the grid is 0 to 90°, preferably 30 to 90°; the spacing L between adjacent metal wires of the grid strip is 0.5 to 3 cm, preferably 1 to 2 cm; and the width of the grid strip is 0.1 to 0.5 cm, preferably 0.1 to 0.2 cm. Preferably, the diameter-to-height ratio D / H of the cylindrical device is 0.1 to 0.5, more preferably 0.1 to 0.3; Preferably, the two ends of the cylindrical device with the grille are open; Preferably, the top of the outer peripheral curved surface has an external thread, and the bottom of the outer peripheral curved surface has an internal thread, and the plurality of the grid-equipped cylindrical devices can be connected by threads; Preferably, the grid strip is a metal wire, and more preferably, the metal wire is at least one of stainless steel wire, iron wire, copper wire, aluminum wire, titanium wire, etc., with stainless steel wire being the most preferred; And / or, the mesh size of the filter bag is 50 to 500 mesh, preferably 100 to 300 mesh.

11. The application of the modified oxygen-releasing nano-peroxides for degrading organic pollutants as described in any one of claims 1 to 3 and / or the modified oxygen-releasing nano-peroxides prepared by the preparation method of the modified oxygen-releasing nano-peroxides as described in any one of claims 4 to 6 and / or the composite slow-release oxygen material as described in claim 7 and / or the composite slow-release oxygen material prepared by the preparation method of the composite slow-release oxygen material as described in any one of claims 8 to 9 in the remediation of soil and / or groundwater containing organic pollutants.

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