Composite bentonite and bentonite pad and river bank protection formed therefrom

Abstract

The present invention discloses a composite bentonite and a bentonite mat and a river bank protection formed by the composite bentonite. A composite bentonite comprises solidified sediment, bentonite and biomass, wherein the mass ratio of the biomass to the solidified sediment is (5-10):100, and the mass ratio of the bentonite to the solidified sediment is (1-2):1. The composite bentonite of the present invention has the excellent water absorption characteristics of bentonite and contains nutrients that promote plant growth. It has the functions of water retention, air permeability and being conducive to plant germination and rooting growth. It can be used as a river bank protection, and while maintaining high strength, it solves the problem that excessive expansion of bentonite after absorbing water affects plant germination and growth.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental pollution control, and in particular relates to a composite bentonite and a bentonite mat and a river channel slope protection formed by the composite bentonite. Background Art

[0002] my country's efforts to control water pollution are unprecedented, and the number of sewage treatment plants has increased significantly, resulting in a sharp increase in sludge production. Realizing the resource utilization of sludge with land use as the final destination is in line with my country's strategic development direction of energy conservation, emission reduction and circular economy, and is currently a major technical demand for my country's full-chain sludge treatment and disposal.

[0003] In recent years, large-scale human activities have damaged the ecological system of river and lake slope protection. The traditional bank protection structure has adopted a closed form on the river slope, which has made the environmental conditions of the river channel patterned and the biological species single, which has a negative impact on the river ecological environment. The river channel itself has also lost its original water environment and waterside environment functions, which has a great impact on the human living environment. It is urgent to strengthen the ecological restoration and construction of slope protection, restore the slope protection ecological belt, improve the water quality of rivers and lakes, and enhance the quality of the water ecological environment.

[0004] The purpose of ecological dredging of rivers and lakes is to control the endogenous pollution load of rivers and lakes. The dredging targets polluted silt with high nutrient content. Nutrient-rich soil is the basic material for the transformation of ecological slope protection base. Using river and lake silt for ecological slope protection construction is an important measure to protect the ecology of rivers and lakes by combining the resource utilization of dredged sludge with ecological environment construction. It forms key technologies for constructing river slope protection with sludge that can be promoted and applied, so as to effectively solve prominent problems such as the difficulty in removing river and lake sludge, long treatment and disposal period, and deterioration of river slope protection environment, realize the resource utilization of polluted sludge in rivers and lakes and the restoration of water environment, help improve the efficiency of water environment management, and provide scientific and technological support for the comprehensive management of river and lake water environment.

[0005] CN108612050B discloses a method for preparing a sponge soil ecological slope protection by in-situ solidification of dredged mud, wherein a sponge soil solidification layer is prepared by in-situ solidification of dredged mud, wherein the sludge solidifying agent used is traditional aluminate clinker, slag powder, fly ash, quicklime, desulfurized gypsum, etc., the pH value is relatively high, which will reduce the survival rate of plants; at the same time, directly adding porous ash to the sponge solidified soil will cause the solidified soil to be more alkaline, which is more unfavorable to plant growth.

[0006] CN116217022A discloses a sludge solidifying agent and a preparation method and application of solidified sludge. It discloses adding micro-expansion materials such as titanium dioxide, calcium aluminum sulfate, magnesium oxide, calcium oxide, gypsum, etc. to the solidifying agent to fill the gaps between sludge particles and reduce the porosity of the solidified sludge. However, subsequent studies have found that the solidified sludge obtained in this patent has a dense structure and low porosity, which is not conducive to plant rooting and germination, and further leads to a low plant growth rate.

[0007] CN107487846B discloses an ecological hard revetment suitable for variable water levels, in which an oxygenated area and an anaerobic area are arranged below the second vegetation planting area, the oxygenated area is arranged above the conventional water level, and a slow-release oxygen material is placed therein; the anaerobic area is arranged below the conventional water level, and a carrier loaded with facultative anaerobic microorganisms is placed in the anaerobic area, and the carrier is composed of vermiculite, fly ash and perlite; when the water level rises, the slow-release oxygen material releases oxygen and creates an underwater oxygenated environment, and the microorganisms perform aerobic biodegradation, and vice versa, anaerobic biological treatment is performed, thereby creating an alternation of aerobic and anoxic environments to achieve multiple purification treatments of the river water. The planting area uses a soil matrix, and a water purification area, an oxygenated area and an anaerobic area are directly arranged below the planting area, which is easy to collapse after long-term scouring.

[0008] Bentonite pad is a composite waterproof material made by evenly laying bentonite particles between two geotextiles according to certain quality requirements through needle punching and other processes. It is a commonly used geosynthetics in engineering. Bentonite pad mainly uses the principle of bentonite swelling when it meets water. After absorbing water, it forms a uniform and dense colloid system with high viscosity and small hydraulic permeability coefficient to achieve effective anti-leakage effect. Therefore, it is widely used in landfills, underground garages, artificial lakes, etc., mainly for sealing and anti-seepage. The bentonite in the middle of the bentonite pad has excellent water absorption performance. If it is used in river slope protection, it can play a role in slow drying and water retention. At the same time, the rich minerals in bentonite can provide nutrition for plant growth. However, due to the excellent water absorption of bentonite, it can expand violently after absorbing water, and its properties are extremely unstable; at the same time, after the swelling soil absorbs water, it forms a colloidal substance, resulting in poor drainage effect and low porosity of the soil, which is not conducive to plant germination and growth. Summary of the invention

[0009] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a composite bentonite and a bentonite mat and a river slope protection formed therefrom, in order to solve the above-mentioned problems.

[0010] To achieve the above purpose, the present invention specifically adopts the following technical solutions.

[0011] The first aspect of the present invention protects a composite bentonite, comprising solidified sludge, bentonite and biomass, wherein the mass ratio of the biomass to the solidified sludge is (5-10):100, and the mass ratio of the bentonite to the solidified sludge is (1-2):1.

[0012] In view of the fact that bentonite will form a dense colloid with high viscosity and low permeability coefficient after absorbing water, the present invention forms a composite bentonite by compounding solidified bottom mud with high compressive strength and porosity with bentonite and biomass, which has the advantages of water retention, air permeability and being conducive to plant germination and rooting growth; at the same time, humic acid produced by biomass degradation is used to reduce the pH value of the composite bentonite, thereby providing a planting environment conducive to plant growth; thereby, on the basis of ensuring the high strength of the river bank protection soil, the problem of the airtightness of the bentonite after absorbing water affecting the germination and rooting and growth of plants is solved.

[0013] In the composite bentonite of the present invention, the mass ratio of the biomass to the solidified sludge can generally be (5-10):100, (5-7.5):100, (6-9.5):100, (8-10):100, or 5:100, 10:100, or 8:100.

[0014] In the composite bentonite of the present invention, the mass ratio of the bentonite to the solidified sludge can usually be (1-2):1, (1-1.5):1, (1.2-2):1, or 1.5:1, 2:1, or 1:1.

[0015] In the composite bentonite of the present invention, the bentonite is selected from one of sodium bentonite, calcium bentonite, magnesium bentonite and aluminum (hydrogen) bentonite. The types of bentonite in the present invention are divided into sodium bentonite, calcium bentonite, magnesium bentonite and aluminum (hydrogen) bentonite according to the types of exchangeable cations of montmorillonite. The classification standard meets the requirements of "GB12518-1990 Bentonite Mine Geological Exploration Specifications", and its performance parameters meet the requirements of "GB / T 20973-2007 Bentonite" standard.

[0016] Preferably, it is sodium bentonite.

[0017] In the composite bentonite of the present invention, the biomass is selected from one or more of composted rice husks, composted straws and organic fertilizers.

[0018] Preferably, the method for preparing the composted rice husk is as follows: mixing the composite bacterial agent with the rice husk, standing at 45-55°C for 2-3 days, turning the pile after standing, and turning the pile every 3-4 days to obtain the composted rice husk. The composite bacterial agent is 0.01% to 0.1% of the weight of the rice husk; the composite bacterial agent is selected from a mixture of Bacillus amyloliquefaciens, Bacillus licheniformis, yeast, Trichoderma and actinomycetes; when the moisture content of the compost material drops below 30%, the composting is stopped.

[0019] Preferably, the composted straw is prepared by mixing the composite bacterial agent with rice husks, standing at 45-55°C for 2-3 days, turning the pile after standing, and turning the pile every 3-4 days to obtain the composted straw. The composite bacterial agent is 0.01% to 0.1% of the weight of the straw; the composite bacterial agent is selected from a mixture of Bacillus amyloliquefaciens, Bacillus licheniformis, yeast, Trichoderma and actinomycetes; when the moisture content of the compost material drops below 30%, the composting is stopped.

[0020] Preferably, the organic fertilizer is animal manure, such as cow, pig, and sheep manure. In the composite bentonite of the present invention, the solidified sediment comprises sediment, a curing agent, and a foaming agent. The sediment of the present invention is preferably river and lake sediment.

[0021] Preferably, the moisture content of the sludge is 40-60%. The moisture content is tested in accordance with the provisions of GB / T 50123-2019 Geotechnical Test Method Standard, using a drying method, that is, placing the sample in a weighing box weighed to a constant weight, and drying it in an oven at 105°C to 110°C to a constant weight. The moisture content is calculated as a percentage of the reduced weight.

[0022] Preferably, the curing agent comprises the following raw materials in parts by weight:

[0023]

[0024] More preferably, the weight proportion of the plant gum may be 35-55 parts, 35-40 parts, 38-50 parts, 45-55 parts, or 35 parts.

[0025] More preferably, the weight proportion of the plant fiber may be 10 to 30 parts, 10 to 22 parts, 18 to 25 parts, 20 to 30 parts, or 20 parts.

[0026] More preferably, the weight proportion of the surfactant may be 5 to 8 parts, 7 to 9 parts, 8 to 10 parts, or 6 parts.

[0027] More preferably, the weight proportion of the micro-expanding material may be 2 to 6 parts, 2 to 4.5 parts, 3 to 5 parts, 4.6 to 6 parts, or 5 parts.

[0028] More preferably, the weight proportion of the dispersant may be 0.5 to 2 parts, 0.5 to 1.1 parts, 0.8 to 1.5 parts, 1.4 to 2 parts, or 1 part.

[0029] More preferably, the plant gum is selected from one or more of gum arabic, gum tragacanth and gum Persian.

[0030] More preferably, the plant fiber is selected from one or more of straw, fruit shell and wood chips.

[0031] More preferably, the surfactant is selected from one or more of fatty acid glycerol, cocamidopropylamine oxide, sodium n-butyl oleate sulfate and sodium α-olefin sulfonate.

[0032] More preferably, the micro-expanding material is selected from one or more of titanium dioxide, calcium aluminum sulfate, magnesium oxide, calcium oxide and gypsum.

[0033] More preferably, the dispersant is selected from one or more of lignin sulfonate, naphthalene sulfonate formaldehyde condensate, aliphatic hydroxy sulfonate polymer and polycarboxylic acid polymer.

[0034] Further preferably, the lignin sulfonate is selected from one or more of sodium lignin sulfonate, potassium lignin sulfonate and calcium lignin sulfonate.

[0035] More preferably, the naphthalenesulfonate formaldehyde condensate is specifically a β-naphthalenesulfonate formaldehyde condensate, which can be purchased from the market.

[0036] The plant gum in the curing agent of the present invention is a common natural polysaccharide hydrogel material. Compared with traditional curing materials such as cement and lime, the plant gum has the advantages of faster solidification speed and lower dosage. The plant fiber makes it more excellent in terms of tensile strength and easy cracking during drying. The curing agent of the present invention is composed of natural polymer curing agents, which can avoid the problems of high pH value of the solidified soil, excessive hardness, dense structure, and unsuitability for plant growth caused by the use of traditional curing agents.

[0037] Preferably, based on the total mass of the sediment, the added amount of the curing agent can generally be 40-60 mg / g of sediment, or 40-48 mg / g of sediment, or 48-56 mg / g of sediment, or 52-60 mg / g of sediment, or 40 mg / g of sediment, 50 mg / g of sediment, or 60 mg / g of sediment.

[0038] In the composite bentonite of the present invention, the foaming agent is selected from anionic surfactant type foaming agents. The solidified bottom mud prepared by the foaming agent of the present invention enhances the porosity of the solidified bottom mud while maintaining high strength, which is conducive to plant rooting and germination.

[0039] Preferably, the foaming agent is selected from alkyl sulfate surfactants.

[0040] More preferably, the foaming agent is selected from sodium lauryl sulfate, sodium tetradecyl sulfate and sodium hexadecyl sulfate.

[0041] Preferably, based on the total mass of the sludge, the added amount of the foaming agent can usually be 1-2wt%, or 1-1.6wt%, or 1.5-2wt%, or 1wt%, 1.5wt%, or 2wt%.

[0042] The second aspect of the present invention protects a bentonite mat, comprising two textile layers and a bentonite layer located between the two textile layers, wherein the bentonite layer is formed by the composite bentonite as described above.

[0043] The porosity of the bentonite pad of the present invention is 35-40%, which is higher than 30% of bentonite; the permeability coefficient of the composite bentonite of the present invention is 3.0×10 -3 ~6.0×10 -4 m / s, much higher than bentonite’s 4×10 -11 m / s; and the expansion index, durability and other aspects are still good. In summary, the composite bentonite of the present invention has excellent drainage, air permeability, water retention and other functions; at the same time, it is rich in organic matter and minerals, has a moderate pH value, meets the quality standard requirements of planting soil, and can be used for plant cultivation.

[0044] In the bentonite mat of the present invention, the thickness of the bentonite mat is 4 to 6 cm.

[0045] In the bentonite mat of the present invention, the bentonite layer contains plant seeds.

[0046] Preferably, based on the total area of ​​the bentonite layer, the density of the plant seeds is 10 to 25 g / m 2 .

[0047] Preferably, the plant seeds are selected from one or more of the seeds of flowers, lawns and ground cover plants. The plant planting is suitable for the local growth environment. Flower plants include but are not limited to periwinkle, safflower, chrysanthemum, snapdragon, chrysanthemum, bellflower, platycodon, arrowroot, ophiopogon, Pilea, dahlia, gladiolus, canna, tuberose, narcissus, tulip, hyacinth, and ranunculus; lawn plants include but are not limited to ryegrass, buffalo grass, and bermudagrass; ground cover plants include but are not limited to perennial dianthus, barbata, iris, thyme, mirabilis jalapa, hosta, snakeberry, saxifrage, line grass, butterfly flower, vinca rosea, amaryllis, ophiopogon, ivy, ground juniper, ground juniper, calamus, ophiopogon, golden leaf passerby, purple leaf oxalis, star aniseed plate, Philippine white bamboo, safflower, red flower oxalis, dwarf canna, and ranunculus.

[0048] In the bentonite pad of the present invention, the material of the textile layer is selected from one or both of woven fabric and non-woven fabric.

[0049] Preferably, the peel strength of the textile layer is ≥65N / 10cm.

[0050] Preferably, the woven fabric has a gram weight of ≥120 g / m 2 .

[0051] Preferably, the nonwoven fabric has a gram weight of ≥220 g / m 2 .

[0052] The bentonite pad of the present invention is a blanket-like material formed by a needle punching method by wrapping composite bentonite with two layers of textile cloth.

[0053] The third aspect of the present invention protects the use of the composite bentonite as described above or the bentonite mat as described above in river bank protection.

[0054] A fourth aspect of the present invention protects a river slope protection, comprising a slope body arranged on both sides of the river, wherein the slope body comprises a main body and a support layer and a planting layer arranged on the main body in sequence from bottom to top;

[0055] The support layer is formed by the solidified bottom mud as described above;

[0056] The planting layer is formed by the composite bentonite as described above or the bentonite mat as described above.

[0057] In the river bank protection of the present invention, the planting layer is the bentonite mat as described above.

[0058] In the river bank protection of the present invention, a water purification layer is further arranged between the main body and the supporting layer; from the bottom end to the bottom end of the main body, the water purification layer is sequentially provided with a modified biogas residue area, an activated carbon area and a gravel area.

[0059] Preferably, the thickness of the gravel area is 10 to 15 cm.

[0060] More preferably, the gravel area is composed of minerals of different particle sizes, including breccia > 0.5 mm, coarse sand of 0.5-75 μm, and fine sand of 75-25 μm.

[0061] More preferably, the specific surface area of ​​the activated carbon is 500 to 1500 m 2 / g.

[0062] Preferably, the modified biogas residue zone is formed by modified biogas residue.

[0063] More preferably, the preparation method of the modified biogas residue is: 1) pyrolyzing the biogas residue in a protective atmosphere to obtain a pyrolysis product; 2) mixing the pyrolysis product with an acid solution, dehydrating, and drying to obtain modified biogas residue.

[0064] Further preferably, the protective atmosphere is selected from nitrogen.

[0065] More preferably, the pyrolysis temperature is 500-700°C.

[0066] More preferably, the pyrolysis time is 20 to 80 minutes.

[0067] More preferably, during pyrolysis, the heating rate is 10-20°C / min.

[0068] Further preferably, the acid in the acid solution is selected from one of acetic acid, oxalic acid, citric acid, succinic acid and tartaric acid.

[0069] In the river slope protection of the present invention, the thickness of the support layer is 15 to 20 cm.

[0070] In the river bank protection of the present invention, the thickness of the planting layer is 4 to 6 cm.

[0071] In the river slope protection of the present invention, the thickness of the water purification layer is 10 to 15 cm.

[0072] A fifth aspect of the present invention protects a method for preparing a river bank protection using riverbed mud, comprising the following steps:

[0073] The bottom mud, curing agent and foaming agent are mixed to form solidified bottom mud, and a part of the solidified bottom mud is laid on the slopes on both sides of the river channel to form a supporting layer; the remaining solidified bottom mud, biomass and bentonite are mixed to form composite bentonite, the composite bentonite and plant seeds are placed between two layers of textile to form a bentonite mat, and the bentonite mat is placed on the supporting layer to form a planting layer.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] 1) The composite bentonite prepared by the present invention using a foaming agent enhances the porosity of the composite bentonite while maintaining high strength, which is beneficial to plant rooting and germination; at the same time, the humic acid produced by biomass degradation can reduce the pH value of the composite bentonite, and a planting environment beneficial to plant growth is provided by regulating the pH value; the composite bentonite prepared by solidifying bottom mud, biomass and bentonite has the functions of water retention, air permeability and being beneficial to plant germination and rooting growth; at the same time, on the basis of maintaining the high strength of the river slope protection soil, the problem of the soil being airtight after the bentonite absorbs water, which affects the germination and growth of plants, is solved.

[0076] 2) The bentonite pad of the present invention is provided with geotextiles on the upper and lower surfaces of the composite bentonite, respectively. The porosity of the geotextiles can be adjusted to facilitate the germination of plant seeds, thereby solving the problem of low plant survival rate caused by soil erosion.

[0077] 3) The gravel area of ​​the water purification layer in the river slope protection of the present invention uses sand and gravel of different particle sizes screened out from the dredged sludge as raw materials to achieve resource recycling; the modified biogas residue has a certain porosity and can realize microbial biofilm formation, which not only purifies water quality, but also realizes the material and energy exchange between the aquatic ecosystem and the terrestrial ecosystem, improves biodiversity, and meets the dual functions of river construction and ecological restoration.

[0078] 4) The planting layer and the supporting layer of the river slope protection of the present invention are based on river and lake dredged sludge as the base material, realizing different functionalization of the sludge, forming an ecological slope protection technology using dredged sludge as engineering material, and simultaneously realizing the resource utilization of dredged sludge and ecological restoration of river slope protection, which has good social, economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Attached Figure 1 Shown is a schematic structural diagram of the river bank protection of the present invention.

[0080] The following are marked in the accompanying drawings:

[0081] 100 body

[0082] 200 water purification layers

[0083] 201 Modified digestate area

[0084] 202 Activated Carbon Area

[0085] 203 Gravel Area

[0086] 300 support layers

[0087] 400 planting layers

[0088] 401 bentonite layer

[0089] 402 woven fabric layer

[0090] 403 non-woven fabric layer DETAILED DESCRIPTION

[0091] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0092] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0093] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0094] In the following embodiments of the present application, the curing agent is composed of: 35 parts of plant gum, 20 parts of plant fiber, 6 parts of surfactant, 5 parts of micro-expansion material, and 1 part of dispersant; each substance is mixed according to a proportion. The plant gum is gum arabic, the plant fiber is straw, the surfactant is sodium n-butyl oleate sulfate, the micro-expansion material is nano titanium dioxide, and the dispersant is calcium lignin sulfonate.

[0095] Example 1

[0096] This embodiment 1 provides a composite bentonite and a bentonite pad.

[0097] The formula of composite bentonite is: 100g solidified sludge, 150g sodium-based bentonite, and 5g composted rice husk.

[0098] The preparation method of solidified sludge is as follows: taking sludge with a water content of 60%, a curing agent and a foaming agent and mixing them to obtain solidified sludge. Based on the total mass of the sludge, the amount of the curing agent added is 60 mg / g of the sludge, and the amount of the foaming agent added is 1wt% of the mass of the sludge. Specifically, the sludge is 1000 g, the amount of the curing agent added is 60 g, and the amount of the foaming agent added is 10 g. The foaming agent is sodium dodecyl sulfate.

[0099] The method for preparing composted rice husks is as follows: mixing a composite bacterial agent with rice husks, standing at 50°C for 3 days, turning the compost after standing, and turning the compost once every 3 to 4 days to obtain the composted rice husks. The composite bacterial agent is 0.05% of the weight of the rice husks; the composite bacterial agent is selected from Bacillus amyloliquefaciens; and when the moisture content of the compost material drops below 30%, the composting is stopped.

[0100] Bentonite pad, a non-woven fabric layer is set on one side of the composite bentonite, and a woven fabric layer is set on the other side. The woven fabric has a gram weight of 200g / m 2 The weight of non-woven fabric is 250g / m 2 The peel strength of the non-woven fabric layer and the woven fabric layer is 80N / 10cm. The thickness of the entire bentonite mat is 4cm. The composite bentonite contains plant seeds, the plant is ryegrass, and the density of the plant seeds is 10g / m 2 .

[0101] The solidified sediment was subjected to a sediment solidification test (testing the unconfined compressive strength of the sediment sample after 7 days of curing). The test result showed that the 7-day unconfined compressive strength was 415kPa. The test method of the 7-day unconfined compressive strength refers to the method of the standard "JTG3430-2020 Highway Geotechnical Test Code".

[0102] Example 2

[0103] This embodiment 2 provides a composite bentonite and a bentonite pad.

[0104] The formula of composite bentonite is: 100g solidified sludge, 200g sodium-based bentonite, and 10g composted rice husk.

[0105] The preparation method of solidified sludge is as follows: sludge with a water content of 50% is mixed with a foaming agent and a curing agent to obtain solidified sludge. Based on the total mass of the sludge, the amount of the curing agent added is 40 mg / g sludge, and the amount of the foaming agent added is 2 wt% of the total mass. Specifically, the sludge is 1000 g, the amount of the curing agent added is 40 g, and the amount of the foaming agent added is 20 g. The foaming agent is sodium hexadecyl sulfate.

[0106] See Example 1 for the composted rice husk.

[0107] Bentonite pad, a non-woven fabric layer is set on one side of the composite bentonite, and a woven fabric layer is set on the other side. The woven fabric has a gram weight of 1800g / m 2 The weight of non-woven fabric is 230g / m 2 The peel strength of the non-woven fabric layer and the woven fabric layer is 90N / 10cm. The thickness of the entire bentonite mat is 5cm. The composite bentonite contains plant seeds, the plant is King Bamboo Grass, and the density of the plant seeds is 17g / m 2 .

[0108] The solidified sediment was subjected to a sediment solidification test (testing the unconfined compressive strength of the sediment sample after 7 days of curing). The test result showed that the 7-day unconfined compressive strength was 389 kPa. The test method of the 7-day unconfined compressive strength refers to the method of the standard "JTG3430-2020 Highway Geotechnical Test Code".

[0109] Example 3

[0110] This embodiment 3 provides a composite bentonite and a bentonite pad.

[0111] The formula of composite bentonite is: 100g solidified sludge, 100g sodium-based bentonite, and 8g composted rice husk.

[0112] The preparation method of solidified sludge is as follows: sludge with a water content of 40% is mixed with a foaming agent and a curing agent to obtain solidified sludge. Based on the total mass of the sludge, the amount of the curing agent added is 50 mg / g sludge, and the amount of the foaming agent added is 1.5 wt% of the mass of the sludge. Specifically, the sludge is 1000 g, the amount of the curing agent added is 50 g, and the amount of the foaming agent added is 15 g. The foaming agent is sodium tetradecyl sulfate.

[0113] See Example 1 for the composted rice husk.

[0114] Bentonite pad, a non-woven fabric layer is set on one side of the composite bentonite, and a woven fabric layer is set on the other side. The woven fabric has a gram weight of 300g / m 2 The weight of non-woven fabric is 400g / m 2 The peel strength of the non-woven fabric layer and the woven fabric layer is 100N / 10cm. The thickness of the entire bentonite mat is 6cm. The composite bentonite contains plant seeds, the plant is King Bamboo Grass, and the density of the plant seeds is 25g / m 2 .

[0115] The solidified sediment was subjected to a sediment solidification test (testing the unconfined compressive strength of the sediment sample after 7 days of curing). The test result showed that the 7-day unconfined compressive strength was 456 kPa. The test method of the 7-day unconfined compressive strength refers to the method of the standard "JTG3430-2020 Highway Geotechnical Test Procedure".

[0116] Example 4

[0117] This embodiment 4 provides a composite bentonite and a bentonite pad, which is different from the embodiment 1 in that straw is used instead of rice husk, and the rest is the same as the embodiment 1.

[0118] Example 5

[0119] This embodiment 4 provides a composite bentonite and a bentonite mat, which is different from the embodiment 1 in that organic fertilizer cow dung is used instead of composted rice husks, and the rest is the same as the embodiment 1.

[0120] The performance indicators of the composite bentonites of Examples 1 to 3 were tested, and pure sodium-based bentonite and pure soil were used as control groups.

[0121] The expansion index, durability and filtration loss of composite bentonite are tested using "JG / T 193-2006 Sodium-based bentonite waterproof blanket".

[0122] The porosity and permeability coefficient of composite bentonite are tested using the "GB / T 50123-2019 Geotechnical Test Method Standard".

[0123] The porosity, seed germination rate and permeability coefficient of composite bentonite were evaluated using the "DG / TJ 08-231-2013 Quality Standard for Landscaping Planting Soil". The results are shown in Table 1.

[0124] The expansion index is an important indicator for evaluating the volume change of bentonite under the action of water. The higher the particle expansion index, the greater the volume change of bentonite when absorbing moisture, and the better the water retention capacity and stability. Durability is an important parameter for evaluating the weathering and erosion resistance of bentonite. The higher the particle durability, the more effective the bentonite can be in preventing soil erosion, protecting vegetation growth, and providing a reliable engineering foundation. Filtration loss is one of the indicators for evaluating the filtration performance of bentonite. The smaller the filtration loss, the better the filtration effect and solid particle retention capacity of the bentonite.

[0125] Table 1

[0126] Standard requirements Example 1 Example 2 Example 3 Bentonite soil Filtration loss (mL) ≤18 19 21 20 17 35 Swelling index (ml / 2g) ≥24 20 21 20 25 8 Bentonite durability (ml / 2g) ≥20 22 23 22 24 11 Permeability coefficient (m / s) <![CDATA[≥10 -4 ]]> <![CDATA[4.72×10 -4 ]]> <![CDATA[4.24×10 -4 ]]> <![CDATA[5.59×10 -4 ]]> <![CDATA[4.72×10 -11 ]]> <![CDATA[10 -4 ~10 -5 ]]> Porosity (%) ≥10 38 40 35 30 32 Seed germination rate (%) >80 91 90 94 70 84

[0127] As can be seen from Table 1, due to the doping of solidified sludge and biomass, part of the bentonite is replaced, affecting the expansion index, durability and other parameters, but compared with ordinary soil, it has achieved the effect of retaining water and preventing erosion; and the permeability coefficient of the composite bentonite of the present invention is significantly higher than that of pure bentonite and pure soil, and the porosity is increased, and the seed germination rate meets the planting soil quality standard, and can be used for plant cultivation.

[0128] The bentonite pads of Examples 1 to 3 were tested for various performance indicators, and a bentonite pad formed of pure sodium-based bentonite was used as a control group. The preparation of the bentonite pad formed of pure sodium-based bentonite was the same as that of Example 1.

[0129] The performance parameters of the bentonite pads of Examples 1 to 3, such as mass per unit area, tensile strength, elongation under maximum load, and peel strength, were tested using "JG / T 193-2006 Sodium-based bentonite waterproof blanket". The results are shown in Table 2.

[0130] Table 2

[0131] Standard requirements Example 1 Example 2 Example 3 Bentonite pad <![CDATA[Mass per unit area of bentonite mat (g / m 2 )]]> ≥5000 5500 5500 5500 5500 Tensile strength (longitudinal) (N / 100mm) ≥600 1570 1712 1342 1441 Elongation under maximum load (longitudinal) (%) ≥10 15 17 12 15 Peel strength (N / 100mm) ≥40 189 191 185 190

[0132] As can be seen from Table 2, the tensile strength, elongation and peel strength of the bentonite pads in Examples 1-3 meet the requirements of the standard "JG / T193-2006 Sodium-based Bentonite Waterproof Blanket", and all meet the performance requirements of pure bentonite pads, that is, meet the engineering performance requirements, and can be used for river slope protection.

[0133] Example 6

[0134] like Figure 1 As shown, this embodiment 6 provides a river slope protection, including a slope body arranged on both sides of the river, the slope body including a main body 100 and a support layer 300 and a planting layer 400 arranged on the main body 100 in sequence from bottom to top;

[0135] The support layer 300 is formed by solidified bottom mud;

[0136] The planting layer 400 is formed of composite bentonite or bentonite mat.

[0137] In some embodiments, the angle of the body 100 is 10-60°, preferably 45°. The angle in the present invention refers to the angle between the slope and the ground.

[0138] In some embodiments, the planting layer 400 is formed by a bentonite mat, which includes a bentonite layer 401 , a woven fabric layer 402 , and a textile fabric layer 403 .

[0139] The top and bottom of the main body 100 are each provided with an anchor trench, and the top and bottom of the bentonite pad are anchored in the anchor trenches respectively and compacted by soil. The width of the bentonite pad matches the width of the main body 100 .

[0140] In some embodiments, a water purification layer 200 is further provided between the body 100 and the support layer 300. In some embodiments, the water purification layer 200 is provided with a modified biogas residue area 201, an activated carbon area 202 and a gravel area 203 in sequence from the bottom end to the top end of the body. The water purification filter material formed by the modified biogas residue, activated carbon and gravel in the water purification layer 200 in the present application can remove suspended particles and chemicals in rainwater. The water purification layer 200 can remove more than 80% of pollutants such as ammonia nitrogen and heavy metals.

[0141] The specific surface area of ​​the activated carbon in the activated carbon zone 202 is 500 to 1500 m 2 / g.

[0142] The thickness of the gravel area 203 is 30 to 50 cm. The thickness in this application refers to the length in the direction perpendicular to the slope surface of the slope. The gravel area 203 is composed of minerals of different particle sizes, including >0.5 mm breccia, 0.5 to 75 μm coarse sand, and 75 to 25 μm fine sand. The pollutants intercepted are of different sizes, layer by layer.

[0143] The modified biogas residue area 201 is formed by modified biogas residue. The modified biogas residue has a certain porosity and can realize microbial biofilm, which not only purifies water quality, but also realizes the material and energy exchange between the aquatic ecosystem and the terrestrial ecosystem, improves biodiversity, and satisfies the dual functions of river channel construction and ecological restoration. The preparation method of the modified biogas residue is: 1) in a protective atmosphere, the biogas residue is pyrolyzed to obtain a pyrolysis product; 2) the pyrolysis product is mixed with an acid solution, dehydrated, and dried to obtain modified biogas residue. The protective atmosphere is selected from nitrogen. The pyrolysis temperature is 500 to 700°C. The pyrolysis time is 20 to 80 minutes. During pyrolysis, the heating rate is 10 to 20°C / min. The acid in the acid solution is selected from one of acetic acid, oxalic acid, citric acid, succinic acid and tartaric acid. In a specific embodiment, the modified biogas residue is prepared as follows: 1) under nitrogen protection conditions, the temperature is increased to 600°C at a heating rate of 20°C / min, the pyrolysis time is 60 minutes, and the pyrolysis product is obtained by cooling to room temperature; 2) the pyrolysis product is added to a 5v / v% acetic acid solution, soaked at 60°C, dehydrated, and dried to obtain the modified biogas residue.

[0144] In some embodiments, the water purification layer 200 has a thickness of 10 to 15 cm.

[0145] In some embodiments, the support layer 300 has a thickness of 15 to 20 cm.

[0146] In some embodiments, the planting layer 400 has a thickness of 4 to 6 cm.

[0147] The river slope protection of the present invention, the planting layer and the supporting layer all contain solidified bottom mud, which can remove a part of ammonia nitrogen and heavy metal pollutants; the modified sludge area, activated carbon area and gravel area of ​​the water purification layer can adsorb a part of ammonia nitrogen and heavy metal pollutants; according to statistics, the river slope protection of the present invention can remove more than 80% of ammonia nitrogen and heavy metal pollutants.

[0148] Example 7

[0149] This embodiment 7 provides a method for preparing river bank protection using riverbed mud, comprising the following steps:

[0150] 1) The solidified bottom mud of Example 1 was laid on the slopes on both sides of the river channel to form a support layer with a thickness of 18 cm;

[0151] 2) The bentonite mat containing ryegrass seeds of Example 1 was laid on the support layer to form a planting layer with a thickness of 5 cm.

[0152] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A river bank protection, comprising slopes arranged on both sides of the river, characterized in that: The slope body comprises a main body (100) and a support layer (300) and a planting layer (400) which are sequentially arranged on the main body (100) from bottom to top; The support layer (300) is formed of solidified sediment; the planting layer (400) is formed of a bentonite mat; the bentonite mat is composed of two textile layers and a bentonite layer located between the two textile layers; the bentonite layer is formed of composite bentonite; the composite bentonite is composed of solidified sediment, bentonite and biomass; the mass ratio of the biomass to the solidified sediment is (5-10):100; the mass ratio of the bentonite to the solidified sediment is (1-2):1; The raw materials for solidifying the bottom mud are composed of bottom mud, a curing agent and a foaming agent; The foaming agent is selected from one or more of sodium lauryl sulfate, sodium tetradecyl sulfate and sodium hexadecyl sulfate; Based on the total mass of the sludge, the amount of the foaming agent added is 1-2 wt%; based on the total mass of the sludge, the amount of the curing agent added is 40-60 mg / g of sludge; The porosity of the composite bentonite is 35-40%, and the permeability coefficient is 3.0×10 -3 ~6.0×10 -4 m / s; The curing agent comprises the following raw materials in parts by weight: 35-55 parts of plant gum 10-30 parts of plant fiber Surfactant 5-10 parts 2 to 6 micro-expansion materials Dispersant 0.5-2 parts; The plant gum is selected from one or more of gum arabic, gum tragacanth and gum Persian; The surfactant is selected from one or more of fatty acid glycerol, cocamidopropylamine oxide, sodium n-butyl oleate sulfate and sodium α-olefin sulfonate; The micro-expanding material is selected from one or more of titanium dioxide, calcium aluminum sulfate, magnesium oxide, calcium oxide and gypsum.

2. The river bank protection as claimed in claim 1, characterized in that: The bentonite is selected from one of sodium-based bentonite, calcium-based bentonite, magnesium-based bentonite and aluminum-based bentonite; And / or, the biomass is selected from one or more of composted rice husks, composted straws and animal manure.

3. The river bank protection according to claim 1, characterized in that: The moisture content of the bottom mud is 40-60%.

4. The river bank protection according to claim 1, characterized in that: The plant fiber is selected from one or more of straw, fruit shell and sawdust; And / or, the dispersant is selected from one or more of lignin sulfonate, naphthalene sulfonate formaldehyde condensate, aliphatic hydroxy sulfonate polymer and polycarboxylic acid polymer.

5. The river bank protection according to claim 1, characterized in that: The material of the textile layer is selected from one or both of woven fabric and non-woven fabric; And / or, the bentonite layer contains plant seeds, and the plant seeds are selected from one or more of flower, lawn and ground cover plant seeds; And / or, the bentonite pad has a thickness of 4 to 6 cm.

6. The river bank protection according to claim 1, characterized in that: Based on the total area of ​​the bentonite layer, the density of the plant seeds is 10 to 25 g / m 2 ; And / or, the peel strength of the textile layer is ≥65N / 10cm; And / or, the woven fabric has a gram weight of ≥120 g / m 2 ; And / or, the nonwoven fabric has a gram weight of ≥220 g / m 2 .

7. The river bank protection according to claim 1, characterized in that: A water purification layer (200) is also provided between the body (100) and the support layer (300); along the bottom end to the top end of the body, the water purification layer (200) is provided with a modified biogas residue area (201), an activated carbon area (202) and a gravel area (203) in sequence; And / or, the thickness of the support layer (300) is 15 to 20 cm.

8. The river bank protection as claimed in claim 7, characterized in that: The thickness of the water purification layer (200) is 10 to 15 cm.

9. The river bank protection as claimed in claim 7, characterized in that: The gravel area (203) is composed of minerals of different particle sizes, including angular gravels of >0.5 mm, coarse sand of 0.5-75 μm, and fine sand of 75-25 μm.

10. The river bank protection according to claim 7, characterized in that: The thickness of the gravel area (203) is 10 to 15 cm.

11. The river bank protection according to claim 7, characterized in that: The modified biogas residue zone (201) is formed by modified biogas residue.

12. The river bank protection according to claim 7, characterized in that: The preparation method of the modified biogas residue is as follows: 1) pyrolyzing the biogas residue in a protective atmosphere to obtain a pyrolysis product; 2) mixing the pyrolysis product with an acid solution, dehydrating, and drying to obtain the modified biogas residue.

13. The river bank protection according to claim 12, characterized in that: The protective atmosphere is selected from nitrogen.

14. The river bank protection according to claim 12, characterized in that: The pyrolysis temperature is 500-700°C.

15. The river bank protection according to claim 12, characterized in that: The pyrolysis time is 20 to 80 minutes.

16. The river bank protection according to claim 12, characterized in that: During pyrolysis, the heating rate is 10-20°C / min.

17. The river bank protection according to claim 12, characterized in that: The acid in the acid solution is selected from one of acetic acid, oxalic acid, citric acid, succinic acid and tartaric acid.

18. A method for preparing river bank protection using riverbed mud, characterized in that: The steps include: The bottom mud, a curing agent and a foaming agent are mixed to form a solidified bottom mud, and a part of the solidified bottom mud is laid on the slopes on both sides of the river channel to form a supporting layer; the remaining solidified bottom mud, biomass and bentonite are mixed to form the composite bentonite as claimed in claim 1, the composite bentonite and plant seeds are placed between two layers of textile to form a bentonite mat, and the bentonite mat is placed on the supporting layer to form a planting layer.

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