A manganese-modified biochar sediment active blanket

Abstract

The application discloses a manganese-modified biochar sediment active covering blanket and belongs to the technical field of sediment pollution ecological restoration of rivers and lakes and environmental functional adsorption material components.The manganese-modified biochar sediment active covering blanket comprises a water-permeable and shaped protective layer, an active adsorption functional layer and a sediment blocking buffer layer which are sequentially arranged from top to bottom and connected into an integrated whole.The active adsorption functional layer comprises a fiber base and manganese-modified biochar mixed particles embedded in the fiber base.The water-permeable and shaped protective layer forms a water-permeable and anti-disturbance outer surface, the active adsorption functional layer adsorbs and degrades pollutants in the sediment, and the sediment blocking buffer layer blocks the sediment.Three-layer composite structure of the manganese-modified biochar sediment active covering blanket makes the whole covering blanket into a flexible blanket-shaped structure which can be curled, cut and laid, and can reduce the loss and disturbance risk of the manganese-modified biochar mixed particles when directly added.

Description

Technical Field

[0001] This invention relates to the technical field of ecological restoration of river and lake sediment pollution and environmental functional adsorption material components, specifically a manganese-modified biochar sediment active covering blanket. Background Technology

[0002] Organic pollutants such as antibiotics may accumulate in the bottom sediments of rivers, lakes, reservoirs, and aquaculture water bodies. These pollutants can be released into the overlying water and spread as an endogenous source of pollution when subjected to hydrodynamic disturbances, biological disturbances, sediment resuspension, or changes in the physicochemical conditions of the water body. In-situ covering technology, which involves placing covering materials on the surface of contaminated sediments, can reduce sediment disturbance and impede pollutant migration, and is a common engineering approach in sediment remediation.

[0003] Biochar and modified biochar, with their porous structure and large surface contact space, are often used as environmental adsorbents. Manganese-modified biochar, as a functional carbon-based material, has a basis for application in the retention of antibiotic pollutants. However, conventional manganese-modified biochar is mostly in powder or loose granular form. When directly added to the sediment surface, it is easily washed away, dispersed, and locally accumulated due to water flow shearing, sediment tumbling, construction disturbance, or biological activity, making it difficult to form a stable and continuous covering interface.

[0004] Furthermore, current preparations and applications of manganese-modified biochar primarily focus on loading manganese oxides, such as manganese dioxide. Their adsorption and degradation performance for pollutants is significantly affected by the preparation process, raw material ratios, and environmental conditions, leaving room for improvement. Moreover, there is currently a lack of mature technical solutions for combining manganese-modified biochar with engineered covering structures to achieve stable and efficient operation in in-situ sediment remediation.

[0005] Existing ecological restoration blankets, vegetation blankets, or geotextile cover blankets are mostly composed of fiber layers, geotextile layers, or mesh layers, typically focusing on soil stabilization, erosion prevention, or slope protection. They lack functional carbon-based structures specifically designed to intercept antibiotic pollutants. Some composite carbon-based cover structures use single-layer filling or simple clamping methods, resulting in insufficient bonding between the carbon material and the blanket body. Under long-term immersion and disturbance conditions, problems such as carbon particle leakage, localized cavitation, and blockage of functional layers by bottom sediment particles may occur.

[0006] Therefore, it is necessary to provide a sediment active cover blanket that stably confines modified and optimized manganese-modified biochar particles within the sediment active cover blanket, and improves the stability and engineering applicability of the sediment in-situ cover remediation component through a layered structure of surface permeable protection, middle active adsorption, and bottom mud-blocking buffer. Summary of the Invention

[0007] The purpose of this invention is to provide a manganese-modified biochar deposit active covering blanket to solve the technical problems mentioned in the background section.

[0008] The technical solution to achieve the objective of this invention is: This invention discloses a manganese-modified biochar sediment active covering blanket, comprising a permeable shaping and protective layer, an active adsorption functional layer, and a sediment barrier buffer layer. The permeable shaping and protective layer covers the upper side of the active adsorption functional layer and is connected to it. The sediment barrier buffer layer covers the lower side of the active adsorption functional layer and is connected to it, forming a flexible blanket that can be rolled up, cut, and laid. The active adsorption functional layer includes a fiber substrate and manganese-modified biochar mixed particles confined within the fiber substrate. At least a portion of the pores in the fiber substrate are smaller than the lower limit of the particle size of the manganese-modified biochar particles. The permeable shaping and protective layer has permeable pores for maintaining water exchange and also provides outer surface shaping and anti-disturbance protection for the active adsorption functional layer. The sediment barrier buffer layer covers the lower side of the active adsorption functional layer and has sediment-blocking pores smaller than the pore size of the permeable shaping and protective layer, which are positioned on one side of the sediment and form a fine barrier interface during use.

[0009] Furthermore, the thickness of the active adsorption functional layer is 3~30mm.

[0010] Furthermore, the fiber substrate includes an upper fiber mesh, a lower fiber mesh, and connecting fibers. The connecting fibers are disposed between the upper fiber mesh and the lower fiber mesh, forming a three-dimensional fiber network with the upper fiber mesh and the lower fiber mesh. The three-dimensional fiber network contains multiple containment units, and the manganese modified biochar mixed particles are confined within the containment units.

[0011] Furthermore, the shape of the receiving unit is rectangular, rhomboid, honeycomb, or strip-shaped; the equivalent side length of the receiving unit is 20mm~200mm.

[0012] Furthermore, the particle size of the manganese-modified biochar mixed particles (4) is 0.3~8 mm.

[0013] Furthermore, the manganese-modified biochar mixed particles are obtained by compounding manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of (8~20):1.

[0014] Furthermore, the preparation steps of the manganese-modified biochar are as follows: Nickel chloride hexahydrate, urea, and manganese chloride hexahydrate were dissolved in ultrapure water. Biochar was then added and ultrasonically vibrated for at least 3 minutes to ensure complete dispersion of the biochar in the solution. The solution was then placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene and maintained at 158-162°C for 15-17 hours. The reactor was then washed 3-5 times alternately with ultrapure water and ethanol on a centrifuge. After drying, the solution was placed in a tube furnace and kept at 300-500°C under a nitrogen atmosphere for 4-5 hours. The solution was then cooled to room temperature to obtain manganese-modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar was (1.1-1.3):1:(0.3-0.34):(800-900):(4.16-8.32).

[0015] Furthermore, the hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: the mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred evenly. The mixture is placed in a constant temperature shaking incubator preheated to 45~60℃ and reacted at a speed of 180r / min for 12h. After the reaction, the mixture is filtered, sealed in a sealed bag, and stored without washing or drying. Unreacted acetic acid, hydrogen peroxide, and generated peracetic acid will remain inside and on the surface of the hydrogen peroxide-modified biochar, thus obtaining hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 35~45%, and the mass percentage of hydrogen peroxide is 15~18%.

[0016] Furthermore, the permeable shaping protective layer includes an outer reinforcing mesh layer and an inner leak-proof mesh layer. The equivalent pore size of the outer reinforcing mesh layer is 2mm~20mm, and the equivalent pore size of the inner leak-proof mesh layer is 0.05mm~2mm. The outer reinforcing mesh layer is used to improve tensile and erosion resistance, and the inner leak-proof mesh layer is used to restrict the outward escape of manganese modified biochar particles.

[0017] Furthermore, the sediment barrier buffer layer includes a fine barrier layer and a support buffer layer; the equivalent pore size of the fine barrier layer is 0.02mm~1mm; the fine barrier layer can be a fine non-woven fabric layer or a fine fiber felt layer; the support buffer layer is a needle-punched felt layer, a woven mesh layer, a non-woven fabric layer or a flexible mesh layer with raised ridges.

[0018] Furthermore, the perimeter of the manganese-modified biochar deposit active covering blanket is provided with an edge sealing strip; the edge sealing strip covers the edge of the three-layer structure and can be provided with connection holes, anchoring holes, ballast bags or overlapping fixing strips.

[0019] Furthermore, one side of the manganese modified biochar deposit active covering blanket is provided with an overlapping edge, and the other side is provided with an overlapping receiving area that cooperates with the overlapping edge. Two adjacent manganese modified biochar deposit active covering blankets are stacked and connected through the overlapping edge and the overlapping receiving area.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The manganese-modified biochar sediment active covering blanket of the present invention includes a permeable shaping and protective layer, an active adsorption functional layer, and a sediment barrier buffer layer. The permeable shaping and protective layer has permeable pores for maintaining water exchange and can simultaneously shape the outer surface of the active adsorption functional layer and protect it from disturbance. The sediment barrier buffer layer covers the lower side of the active adsorption functional layer and has sediment-blocking pores smaller than the pore size of the permeable shaping and protective layer. It is positioned on the sediment side in use and forms a fine barrier interface, creating a clear functional zone that balances permeability, carbon fixation, sediment blocking, and disturbance resistance requirements. The permeable shaping and protective layer covers the sediment layer. An active adsorption functional layer is placed on top of and connected to the active adsorption functional layer. A sediment barrier buffer layer covers the bottom of the active adsorption functional layer and is connected to the active adsorption functional layer to form a flexible blanket that can be rolled up, cut, and laid out. The active adsorption functional layer includes a fiber substrate and manganese-modified biochar mixed particles confined inside the fiber substrate. The fiber substrate confines and fixes the manganese-modified biochar mixed particles. By compounding and modifying manganese-modified biochar to prepare manganese-modified biochar mixed particles, the adsorption and degradation efficiency of manganese-modified biochar for organic pollutants such as antibiotics that may be enriched in the bottom sediments of rivers, lakes, reservoirs, and aquaculture water bodies is improved.

[0021] (2) The manganese-modified biochar mixed particles in the active adsorption functional layer of the present invention are embedded in the fiber substrate to form an embedded anchoring and fixing structure, which can reduce the leakage, local accumulation and loss problems when the granular carbon material is directly added.

[0022] (3) The bottom mud barrier buffer layer of the present invention is provided with fine mud barrier pores, which can reduce the probability of bottom mud particles floating into the active adsorption functional layer and reduce the risk of failure caused by the adsorption layer being covered or blocked by bottom mud.

[0023] (4) The manganese-modified biochar mixed particles of the present invention are composed of manganese-modified biochar and hydrogen peroxide-modified biochar. The manganese-modified biochar is made by loading nickel-manganese bimetallic oxides onto biochar using a hydrothermal method with nickel chloride hexahydrate, urea, and manganese chloride hexahydrate as raw materials and then annealing at high temperature. The nickel-manganese bimetallic oxides with needle-like structures are formed on the biochar, which effectively alleviates the blockage of the pores of biochar by traditional manganese oxides. Compared with traditional manganese-modified biochar, it has a larger specific surface area and mesoporous structure, which is conducive to the adsorption of organic pollutants. The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. It increases oxygen-containing functional groups on the surface of biochar, giving full play to its high adsorption capacity and rich oxygen-containing functional groups. It mainly uses chemical adsorption, involving hydrogen bonding, electrostatic interaction, hydrophobic interaction and π-π interaction, which further enhances the adsorption capacity of organic pollutants in sediments. The manganese-modified biochar mixed particles are composed of manganese-modified biochar and hydrogen peroxide-modified biochar, which can significantly enhance the adsorption capacity of organic pollutants in sediments.

[0024] (5) The manganese modified biochar mixed particles of the present invention are obtained by compounding manganese modified biochar and hydrogen peroxide modified biochar at a mass ratio of (8~20):1. Under this compounding ratio, the residual acetic acid, hydrogen peroxide, and acetic acid peroxide in the hydrogen peroxide modified biochar are gradually dissolved as the manganese modified biochar deposit active covering blanket is used. The dissolved hydrogen peroxide and acetic acid peroxide are rapidly decomposed to generate gas bubbles under the efficient catalytic effect of nickel-manganese bimetallic oxide on the surface of manganese modified biochar. The generation of bubbles drives the manganese modified biochar to move in the active adsorption functional layer, which significantly enhances the fluid micro-mixing effect and the mass transfer efficiency of pollutants to the material surface, thereby further improving the adsorption and degradation efficiency of organic pollutants.

[0025] (6) The manganese modified biochar sediment active covering blanket of the present invention has a structure that can be rolled up, cut, overlapped and anchored, which is convenient for modular laying and replacement on the surface of river and lake sediments and has strong engineering adaptability. Attached Figure Description

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of the structure of a manganese-modified biochar deposit active covering blanket according to an embodiment of the present invention.

[0027] The labels in the attached diagram are as follows: 1. Permeable shaping protective layer; 2. Activated adsorption functional layer; 3. Sediment barrier buffer layer; 4. Manganese modified biochar mixed particles; 5. Fiber substrate; 6. Edge sealing tape. Detailed Implementation

[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of the present invention and to simplify the description, and are not intended to 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 the present invention.

[0033] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances. The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the scope of protection of the present invention.

[0034] Example like Figure 1As shown, the manganese-modified biochar sediment active covering blanket includes a permeable shaping and protective layer 1, an active adsorption functional layer 2, and a sediment barrier and buffer layer 3. The permeable shaping and protective layer 1 covers the upper side of the active adsorption functional layer 2 and is connected to the active adsorption functional layer 2. The sediment barrier and buffer layer 3 covers the lower side of the active adsorption functional layer 2 and is connected to the active adsorption functional layer 2 to form a flexible blanket that can be rolled up, cut, and laid. The active adsorption functional layer 2 includes a fiber substrate 5 and manganese-modified biochar mixed particles 4 confined inside the fiber substrate.

[0035] The permeable shaping protective layer 1 is located on the upper side of the flexible blanket; the permeable shaping protective layer 1 can be made of woven mesh, warp-knitted mesh, needle-punched fiber layer or composite geonet layer; the permeable shaping protective layer 1 includes an outer reinforcing mesh layer and an inner leak-proof mesh layer; the equivalent pore size of the outer reinforcing mesh layer can be 2mm~20mm to provide high permeability and tensile shaping ability; the equivalent pore size of the inner leak-proof mesh layer can be 0.05mm~2mm to restrict the escape of manganese modified biochar mixed particles 4 from the upper side.

[0036] The sediment barrier buffer layer 3 is located on the underside of the flexible blanket and faces the contaminated sediment in use. The sediment barrier buffer layer 3 includes a fine barrier layer and a supporting buffer layer. The fine barrier layer can be a fine non-woven fabric layer, a fiber felt layer, or a microporous geotextile layer with an equivalent pore size of 0.02mm to 1mm. The supporting buffer layer can be a needle-punched felt layer, a woven mesh layer, a non-woven fabric layer, or a flexible mesh layer with raised ridges. The pores of the sediment barrier buffer layer 3 are smaller than those of the permeable shaping protective layer 1, giving the underside a stronger sediment barrier capacity.

[0037] The perimeter of the flexible blanket is provided with an edge sealing strip 6; the edge sealing strip 6 covers the edges of the permeable shaping protective layer 1, the active adsorption functional layer 2 and the bottom mud barrier buffer layer 3, and is fixed by stitching, hot pressing, clamping or bonding structure; the edge sealing strip 6 can be provided with connection holes or anchoring holes; the connection holes or anchoring holes can be used with anchor nails, ballast ropes, ballast rods or flexible connecting strips to improve the stability after laying.

[0038] In another embodiment, ballast bags can also be provided on the edge sealing strip 6. The ballast bags are arranged along the periphery or local area of ​​the flexible blanket. Sandbags, gravel bags or inert counterweights can be placed inside the ballast bags to improve the adhesion stability of the flexible blanket in the underwater environment. The ballast bags are set as structural components at the edge of the flexible blanket.

[0039] In another embodiment, one side of the flexible blanket is provided with an overlap edge and the other side is provided with an overlap receiving area; when multiple flexible blankets are laid, the overlap edge of one flexible blanket covers the overlap receiving area of ​​the adjacent flexible blanket, and can be stacked and connected by connecting strips, anchor holes or ballast structures; this structure facilitates the formation of a continuous covering interface and reduces the risk of exposed gaps between adjacent blankets.

[0040] The active adsorption functional layer 2 is located between the permeable shaping and protective layer 1 and the sediment barrier and buffer layer 3, and is the intermediate functional layer of the flexible blanket. The active adsorption functional layer 2 includes a fiber substrate 5 and manganese-modified biochar mixed particles 4 embedded inside the fiber substrate 5. The fiber substrate 5 includes an upper fiber mesh, a lower fiber mesh, and connecting fibers. The connecting fibers are arranged between the upper and lower fiber meshes, forming a three-dimensional fiber network. The three-dimensional fiber network contains multiple containment units, and the pore size of each fiber mesh is smaller than the particle size of the manganese-modified biochar mixed particles, thereby confining the manganese-modified biochar mixed particles 4 within the containment units to achieve spatial confinement. The carbon particles are fixed within the fiber substrate 5 in both the planar and thickness directions, reducing the concentrated migration of carbon particles within the blanket and mitigating the risk of localized cavitation during long-term immersion or handling. The containment unit can be rectangular, rhomboid, honeycomb, or strip-shaped. When using rectangular or rhomboid units, their equivalent side length can be 20mm~200mm. When using strip-shaped units, their strip width can be 20mm~150mm. The thickness of the active adsorption functional layer 2 can be 3mm~30mm. The manganese-modified biochar mixed particles 4 can be granular bodies with a particle size of 0.3mm~8mm. The above dimensions can be selected according to the degree of sediment pollution, hydrodynamic conditions, and ease of construction.

[0041] The manganese-modified biochar mixed particles are obtained by compounding manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of (8~20):1; the preparation steps of the manganese-modified biochar are as follows: Nickel chloride hexahydrate, urea, and manganese chloride hexahydrate were dissolved in ultrapure water. Biochar was then added and ultrasonically vibrated for at least 3 minutes to ensure complete dispersion of the activated carbon in the solution. The solution was then placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene and maintained at 158-162°C for 15-17 hours. The reactor was then washed 3-5 times alternately with ultrapure water and ethanol on a centrifuge. After drying, the solution was placed in a tube furnace and kept at 300-500°C under a nitrogen atmosphere for 4-5 hours. The solution was then cooled to room temperature to obtain manganese-modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar was (1.1-1.3):1:(0.3-0.34):(800-900):(4.16-8.32).

[0042] The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: A mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred until homogeneous. The mixture is then placed in a constant temperature shaking incubator preheated to 45-60℃ and reacted at a speed of 180 r / min for 12 h. After the reaction, the mixture is filtered, sealed in a sealed bag, and stored without washing or drying. Unreacted acetic acid, hydrogen peroxide, and generated peracetic acid will remain inside and on the surface of the hydrogen peroxide-modified biochar, thus obtaining hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 35-45%, and the mass percentage of hydrogen peroxide is 15-18%.

[0043] The preparation steps of biochar are as follows: Weigh 50.0g of dried and pulverized birch wood chips into a quartz crucible, place it in a tube furnace, and heat at a rate of 0.1m... 3 Under the protection of high-purity nitrogen gas, the temperature was increased to 300℃ at a rate of 10℃ / min for 2 hours for pyrolysis. After the reaction was completed, the biochar was taken out, sealed in a sealing bag, and the biochar was obtained.

[0044] Example 1 The structure of the manganese-modified biochar deposit active covering blanket in Example 1 is the same as that in the above examples, except that: In this embodiment, the permeable shaping protective layer 1 is composed of an outer reinforcing mesh layer and an inner leak-proof mesh layer; the outer reinforcing mesh layer is made of high-density polyethylene bidirectional geonet with a basis weight of 80 g / m². 2 The thickness is 1.5 mm, and the mesh size is 5 mm × 5 mm; the inner leak-proof mesh layer is made of polypropylene short fiber needle-punched nonwoven geotextile with a basis weight of 100 g / m². 2 The thickness is 0.9 mm, and the equivalent pore size is approximately 0.1–0.2 mm; the total weight of the permeable shaping protective layer 1 is approximately 180 g / m³. 2 The total thickness is approximately 2.4 mm; the material is commercially available.

[0045] The bottom sediment barrier buffer layer 3 is composed of a dense barrier layer and a supporting buffer layer; the dense barrier layer is made of polypropylene short fiber needle-punched nonwoven geotextile with a basis weight of 200 g / m. 2 The thickness is 1.7 mm, and the equivalent pore size is no greater than 0.1 mm; the supporting buffer layer is made of polyester fiber needle-punched felt with a basis weight of 300 g / m². 2 The thickness is 2.5 mm; the total weight of the bottom mud barrier buffer layer 3 is approximately 500 g / m³. 2 The total thickness is approximately 4.2 mm; all materials are commercially available.

[0046] The parameters for the aforementioned short-fiber needle-punched nonwoven geotextiles can be found in GB / T 17638—2017, and the parameters for plastic geonets can be found in GB / T 17689—2008.

[0047] In this embodiment, the fiber substrate 5 is made of polyester staple fiber needle-punched nonwoven felt with a basis weight of 400 g / m². 2 The thickness is 4.0 mm, and the average pore size is 0.2 mm; the manganese-modified biochar mixed particles 4 have a particle size of 0.5~1.0 mm and are embedded and confined within the three-dimensional fiber network of the fiber substrate 5 through a needle-punching composite method; the polyester short fiber needle-punched nonwoven felt is a commercially available product; the area loading of the manganese-modified biochar mixed particles 4 is 2.0 kg / m². 2 The manganese-modified biochar mixed particles 4 are uniformly distributed and confined within the three-dimensional fiber network of the fiber substrate 5.

[0048] In this embodiment, for sediments with a pollution thickness of 10-20 cm, the thickness of the active adsorption functional layer 2 is limited to 10 mm to meet the adsorption and barrier requirements for pollutants in the sediment.

[0049] The manganese-modified biochar mixed granules are obtained by blending manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of 8:1; the preparation steps of the manganese-modified biochar are as follows: Nickel chloride hexahydrate, urea, and manganese chloride hexahydrate were dissolved in ultrapure water. Biochar was then added and ultrasonically vibrated for 3 minutes to completely disperse the activated carbon in the solution. The solution was then placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene and kept at 158°C for 17 hours. The reactor was then washed three times alternately with ultrapure water and ethanol on a centrifuge. After drying, the solution was placed in a tube furnace and kept at 300°C under a nitrogen atmosphere for 5 hours. The solution was then cooled to room temperature to obtain manganese-modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar was 1.1:1:0.3:800:4.16.

[0050] The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: A mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred until homogeneous. The mixture is then placed in a constant temperature shaking incubator preheated to 45°C and reacted at a speed of 180 r / min for 12 h. After the reaction, the mixture is filtered, sealed in a sealed bag, and stored without washing or drying. Unreacted acetic acid, hydrogen peroxide, and generated peracetic acid will remain inside and on the surface of the hydrogen peroxide-modified biochar, thus obtaining hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 35%, and the mass percentage of hydrogen peroxide is 18%.

[0051] Example 2 The difference between the manganese-modified biochar deposit active covering blanket in Example 2 and that in Example 1 is: The manganese-modified biochar mixed granules are obtained by blending manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of 20:1; the preparation steps of the manganese-modified biochar are as follows: Nickel chloride hexahydrate, urea, and manganese chloride hexahydrate were dissolved in ultrapure water. Biochar was then added and ultrasonically vibrated for 3 minutes to completely disperse the activated carbon in the solution. The solution was then placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene and kept at 160°C for 16 hours. The reactor was then washed four times alternately with ultrapure water and ethanol on a centrifuge. After drying, the solution was placed in a tube furnace and kept at 500°C under a nitrogen atmosphere for 5 hours. The solution was then cooled to room temperature to obtain manganese-modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar was 1.19:1:0.33:833:6.24.

[0052] The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: A mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred until homogeneous. The mixture is then placed in a constant temperature shaking incubator preheated to 45°C and reacted at a speed of 180 r / min for 12 h. After the reaction, the mixture is filtered, sealed in a sealed bag, and stored without washing or drying. Unreacted acetic acid, hydrogen peroxide, and generated peracetic acid will remain inside and on the surface of the hydrogen peroxide-modified biochar, thus obtaining hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 40%, and the mass percentage of hydrogen peroxide is 18%.

[0053] Example 3 The difference between the manganese-modified biochar deposit activated covering blanket in Example 3 and that in Example 1 is: The manganese-modified biochar mixed granules are obtained by blending manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of 20:1; the preparation steps of the manganese-modified biochar are as follows: Nickel chloride hexahydrate, urea, and manganese chloride hexahydrate were dissolved in ultrapure water. Biochar was then added and ultrasonically vibrated for 3 minutes to completely disperse the activated carbon in the solution. The solution was then placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene and kept at 162°C for 15 hours. The reactor was then washed five times alternately with ultrapure water and ethanol on a centrifuge. After drying, the solution was placed in a tube furnace and kept at 500°C under a nitrogen atmosphere for 4 hours. The solution was then cooled to room temperature to obtain manganese-modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar was 1.3:1:0.34:900:8.32.

[0054] The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: A mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred until homogeneous. The mixture is then placed in a constant temperature shaking incubator preheated to 60°C and reacted at a speed of 180 r / min for 12 h. After the reaction, the mixture is filtered, sealed in a sealed bag, and stored without washing or drying. Unreacted acetic acid, hydrogen peroxide, and generated peracetic acid will remain inside and on the surface of the hydrogen peroxide-modified biochar, thus obtaining hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 45%, and the mass percentage of hydrogen peroxide is 18%.

[0055] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the manganese-modified biochar mixed particles use only manganese-modified biochar.

[0056] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the manganese-modified biochar mixed particles only use commercially available manganese-modified biochar.

[0057] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that the manganese-modified biochar mixed particles were obtained by compounding commercially available manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of 20:1; bamboo biochar was mixed with 0.2 mol·L⁻¹ -1 Potassium permanganate solution was mixed at a carbon-to-manganese mass ratio of 1:10 and stirred for 0.5 h to ensure uniform mixing. The mixture was then vibrated at 16℃ and 40% ultrasonic power for 1 h, followed by standing for 12 h. After filtration, the mixture was dried at 70℃ to constant weight to obtain manganese-modified biochar. Bamboo biochar was commercially available and had a BET specific surface area of ​​245 m². 2 / g, particle size 0.5~1.0mm, total pore volume 0.15cm³ 3 / g.

[0058] Comparative Examples 4-5 The difference between Comparative Examples 4-5 and Example 2 is that the manganese-modified biochar mixed particles are obtained by compounding manganese-modified biochar and hydrogen peroxide-modified biochar in mass ratios of 8:0.3 and 40:1, respectively.

[0059] Example of effect Contaminated sediment with a ciprofloxacin content of 100 mg / kg was placed at the bottom of a circular plastic bucket with a radius of 25 cm and a coverage height of 10 cm. Manganese-modified biochar sediment active covering blankets from Examples 1-3 and Comparative Examples 1-5 were then laid flat on the sediment. Deionized water was then added to simulate overlying water, resulting in an overlying water height of 45 cm. A control group without overlying water was set up, ensuring all other conditions remained the same. At 90 days, the overlying water at a depth of 5 cm below the water surface was collected to test the ciprofloxacin concentration. The test results are shown in Table 1 below. Table 1

[0060] Table 1 shows that the manganese-modified biochar sediment active covering blankets prepared in Examples 1-3 have a better adsorption effect on ciprofloxacin, an organic pollutant in the contaminated sediment. After 90 days of covering, no ciprofloxacin content was detected in the covered water at 5 cm below the water surface. In the blank case, i.e., without covering, the concentration of ciprofloxacin was 0.35 mg / L after 90 days.

[0061] The difference between Comparative Example 1 and Example 2 is that the manganese-modified biochar mixed granules used only manganese-modified biochar, and the concentration of ciprofloxacin in the supernatant water 5 cm below the water surface after 90 days was 0.015 mg / L; the difference between Comparative Example 2 and Example 2 is that the manganese-modified biochar mixed granules used only commercially available manganese-modified biochar, and the concentration of ciprofloxacin in the supernatant water 5 cm below the water surface after 90 days was 0.026 mg / L; the difference between Comparative Example 3 and Example 2 is that the manganese-modified biochar mixed granules were obtained by mixing commercially available manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of 20:1, and the concentration of ciprofloxacin in the supernatant water 5 cm below the water surface after 90 days was... 0.008 mg / L; Compared with Comparative Example 3, the concentration of ciprofloxacin in the overlying water 5 cm below the water surface was lower in Comparative Example 3 after 90 days, indicating that the combination of manganese-modified biochar mixed particles and hydrogen peroxide-modified biochar can enhance the adsorption effect of manganese-modified biochar sediment active covering blanket on ciprofloxacin, an organic pollutant in contaminated sediment; Compared with Example 2, no ciprofloxacin content was detected in the overlying water 5 cm below the water surface after 90 days of covering in Example 2, indicating that the combination of manganese-modified biochar prepared in the example and hydrogen peroxide-modified biochar in the manganese-modified biochar mixed particles has the best adsorption effect on ciprofloxacin, an organic pollutant in contaminated sediment.

[0062] The difference between Comparative Examples 4-5 and Example 2 is that the manganese-modified biochar mixed particles were prepared by mixing manganese-modified biochar and hydrogen peroxide-modified biochar in mass ratios of 8:0.3 and 40:1, respectively. After 90 days, the concentrations of ciprofloxacin in the supernatant water at 5 cm below the water surface were 0.001 mg / L and 0.003 mg / L, respectively. With the increase in the proportion of hydrogen peroxide-modified biochar, the adsorption effect of ciprofloxacin in the supernatant water at 5 cm below the water surface improved after 90 days. Furthermore, in Example 2, the mass ratio of manganese-modified biochar to hydrogen peroxide-modified biochar was 20:1, i.e., 8... When the ratio of manganese-modified biochar to hydrogen peroxide-modified biochar increased to 8:1 as in Example 1, no ciprofloxacin was detected in the overlying water at a depth of 5 cm below the water surface after 90 days of coverage. This indicates that the manganese-modified biochar mixed particles were obtained by compounding manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of (8~20):1. Under this compounding ratio, the manganese-modified biochar sediment activated covering blanket has a better adsorption effect on ciprofloxacin, an organic pollutant in contaminated sediment.

[0063] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A manganese-modified biochar deposit active covering blanket, characterized in that, It includes a permeable shaping and protective layer (1), an active adsorption functional layer (2), and a sediment barrier buffer layer (3); the permeable shaping and protective layer (1) covers the upper side of the active adsorption functional layer (2) and is connected to the active adsorption functional layer (2); the sediment barrier buffer layer (3) covers the lower side of the active adsorption functional layer (2) and is connected to the active adsorption functional layer (2); the active adsorption functional layer (2) includes a fiber substrate (5) and manganese modified biochar mixed particles (4) confined inside the fiber substrate.

2. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, The fiber substrate (5) includes an upper fiber mesh, a lower fiber mesh, and connecting fibers. The connecting fibers are arranged between the upper fiber mesh and the lower fiber mesh to form a three-dimensional fiber network with the upper fiber mesh and the lower fiber mesh. The three-dimensional fiber network contains multiple containment units, and the manganese modified biochar mixed particles (4) are confined within the containment units.

3. The manganese-modified biochar deposit activated covering blanket according to claim 2, characterized in that, The shape of the receiving unit is rectangular, rhomboid, honeycomb, or strip-shaped; the equivalent side length of the receiving unit is 20mm~200mm.

4. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, The particle size of the manganese-modified biochar mixed particles (4) is 0.3~8mm.

5. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, The manganese-modified biochar mixed particles (4) are obtained by compounding manganese-modified biochar and hydrogen peroxide-modified biochar at a mass ratio of (8~20):

1.

6. The manganese-modified biochar deposit active covering blanket according to claim 5, characterized in that, The preparation steps of the manganese modified biochar are as follows: nickel chloride hexahydrate, urea, and manganese chloride hexahydrate are dissolved in ultrapure water, and then biochar is added and ultrasonically vibrated for at least 3 minutes to completely disperse the biochar in the solution. Then, it is placed in a polytetrafluoroethylene-lined stainless steel high-pressure reactor and kept at 158~162℃ for 15~17h. Then, it is washed 3~5 times alternately with ultrapure water and ethanol on a centrifuge. After drying, it is placed in a tube furnace and kept at 300~500℃ under a nitrogen atmosphere for 4~5h. Then, it is cooled to room temperature to obtain manganese modified biochar. The mass ratio of nickel chloride hexahydrate, urea, manganese chloride hexahydrate, ultrapure water, and biochar is (1.1~1.3):1:(0.3~0.34):(800~900):(4.16~8.32).

7. The manganese-modified biochar deposit active covering blanket according to claim 5, characterized in that, The hydrogen peroxide-modified biochar is obtained by modifying biochar with acetic acid and hydrogen peroxide. The specific preparation steps are as follows: the mixed solution of acetic acid and hydrogen peroxide is mixed with biochar at a mass ratio of 10:1 and stirred evenly. The mixture is placed in a constant temperature shaking incubator preheated to 45~60℃ and reacted at a speed of 180r / min for 12h. After the reaction is completed, the mixture is filtered and sealed in a sealed bag to obtain hydrogen peroxide-modified biochar. The mass percentage of acetic acid in the mixed solution of acetic acid and hydrogen peroxide is 35~45%, and the mass percentage of hydrogen peroxide is 15~18%.

8. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, The permeable shaping protective layer (1) includes an outer reinforcing mesh layer and an inner leak-proof mesh layer. The equivalent pore size of the outer reinforcing mesh layer is 2mm~20mm, and the equivalent pore size of the inner leak-proof mesh layer is 0.05mm~2mm.

9. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, The bottom mud barrier buffer layer (3) includes a fine barrier layer and a support buffer layer; the equivalent pore size of the fine barrier layer is 0.02mm~1mm; the support buffer layer is a needle-punched felt layer, a woven mesh layer, a non-woven fabric layer or a flexible mesh layer with protruding ridges.

10. The manganese-modified biochar deposit active covering blanket according to claim 1, characterized in that, One side of the manganese modified biochar deposit active covering blanket is provided with an overlapping edge, and the other side is provided with an overlapping receiving area that cooperates with the overlapping edge. Two adjacent manganese modified biochar deposit active covering blankets are stacked and connected through the overlapping edge and the overlapping receiving area.

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