Modified pervious concrete for riparian zone pesticide remediation as well as preparation method and application of modified pervious concrete
By constructing a composite bacterial system of Bacillus licheniformis and Bacillus polymyxa in concrete and using coral reef sand immobilization technology, the problems of low remediation efficiency and insufficient stability of microbial remediation technology in the treatment of pesticide pollution in riparian zones have been solved, achieving efficient and stable pesticide degradation effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-04-14
AI Technical Summary
Existing microbial remediation technologies suffer from low remediation efficiency, narrow applicability, and insufficient microbial stability in concrete environments, especially in the treatment of pesticide pollution in riverbanks, where they struggle to achieve long-term and stable degradation functions.
A composite microbial system was constructed using Bacillus licheniformis and Bacillus polymyxa, and immobilized using coral reef sand. Combined with gel materials, aggregates, and nano-manganese dioxide, modified permeable concrete was prepared to form a stable biofilm structure, thereby enhancing the survival rate and degradation capacity of microorganisms in the concrete system.
It improves the remediation efficiency and microbial stability of pesticide pollution in riverbanks, achieves efficient and long-term removal of recalcitrant pesticides such as organophosphates, meets the mechanical and permeability requirements of riverbank slope protection projects, and reduces the risk of microbial inactivation.
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Figure CN121850496A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a modified permeable concrete for pesticide remediation of riverbanks, its preparation method and application, belonging to the field of environmental functional materials and bioremediation technology. Background Technology
[0002] As a crucial transitional zone connecting terrestrial and aquatic ecosystems, riparian zones not only perform engineering functions such as stabilizing riverbanks and preventing soil erosion, but also serve as key ecological buffer zones for intercepting, absorbing, and degrading agricultural non-point source pollutants. However, with the intensification of agricultural activities, large quantities of recalcitrant pesticides such as organophosphates are continuously transported into riparian soil and water bodies, leading to the accumulation of ecological risks and posing a long-term threat to regional water environment safety and human health.
[0003] To address the aforementioned pollution, existing remediation technologies mainly include physical, chemical, and biological methods. While physical remediation can remove some pesticides in the short term, it typically relies on energy-intensive equipment or large doses of adsorbent materials, resulting in high costs and potentially leading to secondary environmental burdens such as high material consumption and increased waste. Chemical remediation can achieve rapid removal under experimental conditions, but its reaction pathways are complex and easily affected by anions and organic matter in actual riparian environments. Furthermore, some oxidation processes may generate more toxic or recalcitrant byproducts, reducing its safety. In contrast, bioremediation, especially microbial remediation, offers advantages such as strong in-situ remediation, minimal ecological disturbance, mild reaction processes, and environmental friendliness, and is considered a more suitable technology for controlling pesticide pollution in riparian zones.
[0004] Among existing microbial remediation systems, Bacillus species, due to their ability to form highly resistant spores, maintain a high survival rate even under adverse conditions such as drought, high temperature, high alkalinity, and nutrient deficiency, demonstrating good application potential. However, riparian pollution remediation involves not only the ecological processes of soil and water bodies but also is closely related to engineering structures such as slope protection and embankments. Microbial remediation systems often need to function for a long period within or on the surface of engineering materials to achieve in-situ and continuous pollution control. Therefore, whether microorganisms can maintain stable activity in engineering material systems such as concrete has become a key factor restricting their engineering application.
[0005] Existing microbial remediation technologies still have significant limitations in engineering practice: On the one hand, traditional single-strain remediation systems have relatively limited functions and are difficult to efficiently degrade complex and diverse recalcitrant organic pesticides in riparian zones, thus limiting remediation efficiency and applicability; on the other hand, the concrete materials commonly used in riparian revetment structures are characterized by high alkalinity and high early hydration heat release, which significantly inhibit microbial activity, leading to easy loss of directly applied microbial agents and difficulty in achieving long-term, stable degradation functions within the material system. Current technologies do not pay sufficient attention to the long-term survival and stability of microorganisms in concrete environments, limiting the practical application of microbial remediation technologies in the remediation of pesticide pollution in riparian zones. Summary of the Invention
[0006] The purpose of this invention is to provide a modified permeable concrete for pesticide remediation of riparian zones, its preparation method and application, to solve the problems of low remediation efficiency, narrow applicability and insufficient microbial stability in the prior art.
[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a method for preparing modified permeable concrete for pesticide remediation of riverbanks, comprising: Bacillus licheniformis and Bacillus polymyxa were revived and cultured to obtain Bacillus licheniformis bacterial suspension and Bacillus polymyxaformis bacterial suspension, and the Bacillus licheniformis bacterial suspension and Bacillus polymyxaformis bacterial suspension were mixed to obtain mixed bacterial suspension; Activated coral reef sand is obtained by pre-treating coral reef sand to activate it. Mix the mixed bacterial solution and activated coral reef sand, then solidify them to obtain dual-bacterial immobilized coral reef sand. The gel material, aggregate, nano-manganese dioxide, water, additives, and dual-bacterial immobilized coral reef sand are mixed, solidified, and cured to obtain modified permeable concrete.
[0008] Furthermore, the viable bacteria concentration in the Bacillus licheniformis bacterial solution is 10. 5 ~10 7 CFU / mL, the viable bacterial concentration in the *Bacillus polymyxa* bacterial suspension is 10. 5 ~10 7 CFU / mL; The Bacillus licheniformis is ATCC® 14580, and the Bacillus polymyxa culture is ATCC® 842.
[0009] Furthermore, in the process of mixing Bacillus licheniformis bacterial solution and Bacillus polymyxa bacterial solution to obtain mixed bacterial solution, the ratio of the number of viable bacteria in Bacillus licheniformis bacterial solution to the number of viable bacteria in Bacillus polymyxa bacterial solution is (1~3):1.
[0010] Furthermore, the activated coral reef sand has a particle size of 0.5~2 mm, a porosity of 35%~50%, and a specific surface area of not less than 20 m². 2 / g.
[0011] Furthermore, the activation pretreatment of the coral reef sand includes: The coral reef sand was soaked in a hydrochloric acid solution with a concentration of 0.1~0.5 mol / L for 2~4 h for acid washing. The coral reef sand was then removed and rinsed repeatedly with deionized water until neutral. The coral reef sand was then wetted and activated with sterile phosphate buffer and the pH was adjusted to 6.5~7.5.
[0012] Furthermore, the process of mixing the mixed bacterial solution and activated coral reef sand, and then solidifying it to obtain dual-bacterial immobilized coral reef sand includes: The mixed bacterial solution and activated coral reef sand were mixed at a mass ratio of (1.2~5):1. During the mixing process, the bacterial solution adsorption capacity was 15%~25%. Curing at 25~30 ℃ for 24~48 h yields dual-bacterial immobilized coral reef sand.
[0013] Furthermore, in the process of mixing the gel material, aggregate, nano-manganese dioxide, water, additives and dual-strain immobilized coral reef sand, the additives include water-reducing agents and foaming agents; The mass fractions of each component are: 5-15 parts of double-bacterial immobilized coral reef sand, 120-230 parts of gel material, 270-350 parts of aggregate, 65-70 parts of water, 3-5 parts of water-reducing agent, 6-10 parts of foaming agent, and 2-4 parts of nano manganese dioxide. The gel material includes silica fume and cement, wherein the silica fume is 10-30 parts by mass and the cement is 180-220 parts by mass, and the cement is silicate cement. The aggregate is crushed stone with a particle size of 20-60 mm; The water-reducing agent is a polycarboxylate-based water-reducing agent; The foaming agent is a protein-based foaming agent; The nano-manganese dioxide has a particle size of 24-26 nm and a specific surface area of not less than 150 m². 2 / g.
[0014] Furthermore, the mixing of gel material, aggregate, nano-manganese dioxide, water, additives, and dual-strain immobilized coral reef sand includes: Add gelling material, aggregate, nano manganese dioxide, water, and additives, stir, and maintain the temperature at 20~35 ℃; Add the two-strain immobilized coral reef sand and stir for 10-20 minutes at a temperature of 20-35℃.
[0015] In a second aspect, the present invention provides a modified permeable concrete for pesticide remediation of riverbanks, which is prepared by any of the preparation methods described in the first aspect.
[0016] Thirdly, the present invention provides the application of the modified permeable concrete described in the second aspect, including: deploying the modified permeable concrete in riverbank areas affected by non-point source pollution for in-situ synergistic removal of non-point source pollution. The non-point source pollution is one or more of nitrogen, phosphorus, and pesticides.
[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. This invention employs a composite bacterial system constructed from Bacillus licheniformis and Bacillus polymyxa, and achieves immobilization using coral reef sand. These two types of Bacillus have complementary advantages in the transformation pathways of recalcitrant organophosphate pesticides, achieving higher and more stable degradation efficiency compared to single-species systems. The synergistic significance lies in the fact that Bacillus licheniformis primarily undertakes the initial transformation of pesticide molecules, while Bacillus polymyxa further utilizes intermediate products to complete deep degradation. Furthermore, its metabolic process readily produces extracellular polymers, which enhances the adhesion and aggregation of the bacteria on the coral reef sand surface, forming a more stable immobilized structure. This improves the survival rate and continuous degradation capacity of the bacterial community in the concrete system, thereby increasing remediation efficiency and microbial stability.
[0018] 2. The coral reef sand used in this invention has a porous structure, a large specific surface area, and a certain pH buffering capacity, which can provide a relatively buffered and stable microenvironment for microorganisms. Its abundant microporous structure helps to reduce the direct impact of the strongly alkaline pore solution of concrete on the microorganisms, reduce the risk of microbial inactivation, and at the same time facilitate the formation of biofilm and microbial community aggregation structures, thereby significantly improving the degree of immobilization, survival rate and long-term activity of microorganisms in the material system.
[0019] 3. The modified concrete obtained by this invention, while meeting the mechanical and permeability requirements of riverbank slope protection projects, also possesses in-situ remediation capabilities for pesticide pollution, demonstrating good environmental benefits and application prospects. Test results show that, under representative working conditions, this material effectively reduces total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), and ammonium nitrogen (NH4+). + The system showed high removal efficiency for water quality indicators such as nitrogen oxides (NOx) and recalcitrant organic pesticides such as organophosphates. No obvious secondary pollution was observed during operation, enabling long-term and stable treatment of non-point source pollution in riverbanks. Attached Figure Description
[0020] Figure 1 This is a schematic diagram illustrating the application of modified permeable concrete for pesticide remediation of riverbanks, provided by the present invention. Figure 2 These are SEM images of ordinary permeable concrete and modified permeable concrete provided by the present invention; wherein, (a) is a SEM image of ordinary permeable concrete and (b) is a SEM image of modified permeable concrete. Figure 3 This is a schematic diagram illustrating the change in TN removal efficiency after applying modified permeable concrete according to the present invention; wherein, TN removal efficiency represents total nitrogen removal efficiency; Figure 4 This is a schematic diagram illustrating the change in TP removal efficiency after application of the modified permeable concrete provided by the present invention; wherein, TP removal efficiency represents total phosphorus removal efficiency; Figure 5 This is a schematic diagram illustrating the change in COD removal efficiency after applying modified permeable concrete according to the present invention; wherein, COD removal efficiency represents chemical oxygen demand removal efficiency; Figure 6 The present invention provides the application of modified permeable concrete with NH4. + A schematic diagram illustrating the change in NH4+ removal efficiency; where NH4+ is... + -N removal efficiency indicates ammonia nitrogen removal efficiency; Figure 7 This is a schematic diagram illustrating the change in glyphosate removal efficiency after application of the modified permeable concrete provided by the present invention. Detailed Implementation
[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.
[0022] Example 1
[0023] This embodiment provides a method for preparing modified permeable concrete for pesticide remediation of riverbanks, including the following steps: S1: Preparation of dual-bacterial immobilized coral reef sand.
[0024] Step S11: Resuscitate and culture Bacillus licheniformis (specifically model ATCC® 14580) and Bacillus polymyxa (specifically model ATCC® 842) to prepare a viable bacterial concentration of 10. 6 CFU / mL of Bacillus licheniformis and Bacillus polymyxa were prepared, and then the Bacillus licheniformis and Bacillus polymyxaformis were mixed in a ratio of 3:1 to obtain a mixed bacterial solution. Step S12: Soak the coral reef sand in a 0.3 mol / L hydrochloric acid solution for 3 h for acid washing. After acid washing, rinse repeatedly with deionized water until neutral. Then, use sterile phosphate buffer to wet and activate the coral reef sand, and adjust the pH to 6.5~7.5 to obtain activated coral reef sand. Step S13: Mix the mixed bacterial solution obtained in step S11 with the activated coral reef sand obtained in step S12 at a ratio of 3:1, and solidify at 28 ℃ for 36 h to produce dual-bacterial immobilized coral reef sand.
[0025] S2: Preparation of modified permeable concrete.
[0026] Step S21: Prepare the raw materials according to the following weight ratio: 10 parts of the dual-strain immobilized coral reef sand prepared in S1, 200 parts of silicate cement, 20 parts of silica fume, 300 parts of aggregate (specifically, crushed stone with a particle size of 12mm in this embodiment), 3 parts of nano manganese dioxide, 68 parts of water, 4 parts of water-reducing agent (specifically, PCA®-10 in this embodiment), and 8 parts of foaming agent (specifically, FP-30 in this embodiment).
[0027] In step S22, ordinary silicate cement, silica fume, aggregate, nano manganese dioxide, water, water-reducing agent, foaming agent, and the dual-bacterial immobilized coral reef sand obtained in S1 are added sequentially and mixed. The mixture is then poured into a mold and vibrated to form the concrete. The surface of the formed body is covered with a film and left to stand for 24 hours before demolding. The concrete is then cured for 28 days at 20 ℃ and 95% relative humidity to obtain modified permeable concrete with a dual-bacterial mixing ratio of 3:1 for the remediation of pesticide pollution in riverbank areas.
[0028] Example 2
[0029] This embodiment provides a method for preparing modified permeable concrete for pesticide remediation of riverbanks. The preparation steps are the same as in Embodiment 1, except that the mixing ratio of Bacillus licheniformis bacterial solution and Bacillus polymyxa bacterial solution is adjusted to 1:1.
[0030] Comparative Example 1 The difference between this comparative example and Example 1 is that no microbial culture was added.
[0031] Comparative Example 2 The difference between this comparative example and Example 1 is that only Bacillus licheniformis bacterial solution was added, and no Bacillus polymyxa bacterial solution was added, that is, only Bacillus licheniformis was used to fix coral reef sand.
[0032] Comparative Example 3 The difference between this comparative example and Example 1 is that only Bacillus polymyxa bacterial solution was added, and Bacillus licheniformis bacterial solution was not added, that is, only Bacillus polymyxa was used to fix coral reef sand.
[0033] In the preparation methods provided in Examples 1, 2, 1, 2 and 3, the mass parts of each component are shown in Table 1, where the data in Table 1 are in parts.
[0034] Table 1 - Component Content Table
[0035] The performance of the finished products obtained in Examples 1, 2, 1, 2 and 3 was tested, and the results are shown in Table 2.
[0036] Table 2 - Performance Test Data Table
[0037] The test methods and conditions for each performance item in Table 2 are as follows: Compressive strength: According to the compressive strength test method specified in standard GB / T 50081, the compressive strength of permeable concrete specimens was tested using a pressure testing machine at room temperature. The compressive strength of the concrete specimens was determined after 7 days and 28 days of curing.
[0038] Permeability coefficient: Tested using the constant head method. The permeable concrete specimen is sealed and placed in a permeability coefficient measuring device. Water is poured into the device until the water level exceeds the upper surface of the specimen, maintaining a constant head. After the flow rate stabilizes, a graduated cylinder and stopwatch are used to measure the permeability coefficient over a specified time. The water output in this embodiment Take 10 seconds.
[0039] The permeability coefficient is calculated using the following formula: ; in, The permeability coefficient, For a specified time Water output (mL) The height of the permeable concrete specimen is shown in cm. The cross-sectional area (cm²) of the permeable concrete specimen 2 ), The difference in head (cm) is the difference in water head.
[0040] Porosity: The porosity of the permeable concrete specimens was determined using the water saturation method. The specific steps are as follows: a) Measure the mass of the dried test block. ; b) Add water to the experimental simulation tank to the predetermined water level and measure the mass of the water at this point. ; c) Completely immerse the test block in water and soak for 24 hours to ensure it is fully saturated. If necessary, add a small amount of water to maintain the predetermined water level, then measure the total mass of the graduated container containing the test block and water. ; Porosity is calculated using the following formula: ; in, The density of water, The volume of the permeable concrete test block is given.
[0041] The results showed that all samples achieved good mechanical properties, with 28-day compressive strengths exceeding 20 MPa, meeting the engineering requirements for permeable concrete in riverbank revetments. Furthermore, the addition of coral reef sand carrier to the composite bacterial agent led to a more interconnected pore structure within the concrete, resulting in significantly higher porosity and permeability compared to the comparative example. Examples 1 and 2, while maintaining structural strength, also exhibited high porosity and permeability, achieving a harmonious balance between mechanical properties and functionality, and providing structural support for subsequent pollutant removal.
[0042] Scanning electron microscopy (SEM) analysis results are as follows: Figure 2 As shown. With Figure 2 (a) In comparison, Figure 2 As shown in (b), a large number of coral reef sands loaded with microbial colonies are distributed within the porous structure of the concrete, and continuous biofilms have formed in some cracks and pore walls. This indicates that the microorganisms maintain good activity in the concrete system, are able to stably attach and form biofilm structures, which is beneficial to enhancing their persistence and pesticide degradation ability in complex aquatic environments.
[0043] according to Figure 1 The following tests were conducted to verify the effectiveness of the invention in the application scenarios shown: Concrete samples (uniform specifications; cylinders with a diameter of 10 cm and a height of 10 cm) prepared in Examples 1, 2, 1, 2, and 3 were placed in artificially simulated wastewater after 28 days of standard curing, and the infiltration process of a riverbank zone was simulated under dynamic water flow conditions. Effluent samples were collected at 1, 3, 5, 7, and 14 days of operation, and TN, TP, COD, and NH4 were measured. + -N removal efficiency.
[0044] Determination of total nitrogen concentration: Referring to standard HJ 199-2023, alkaline potassium persulfate was added to the water sample, and digestion was carried out under high temperature and high pressure conditions or online ultraviolet conditions to oxidize ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and most organic nitrogen-containing compounds in the water sample to nitrate. After cooling, titanium trichloride reducing agent was added under acidic conditions to quantitatively reduce nitrate to nitric oxide (NO). NO was introduced into a gas phase molecular absorption spectrometer with a carrier gas (flow rate 0.1~0.2 L / min), and the absorbance was measured at the characteristic wavelength of 214.4 nm. The total nitrogen concentration was calculated according to the calibration curve.
[0045] Determination of total phosphorus concentration: Referring to standard HJ 671-2013, under acidic conditions, phosphorus in various forms in the water sample was hydrolyzed at 125℃ under high temperature and pressure, and then mixed with potassium persulfate digestion solution. After ultraviolet digestion, all phosphorus was oxidized to orthophosphate. Under the catalysis of antimony salt, orthophosphate reacted with ammonium molybdate to form phosphomolybdic heteropolyacid. This compound was reduced to a blue complex by ascorbic acid. The absorbance was measured at a wavelength of 880 nm, and the total phosphorus concentration was calculated according to the calibration curve.
[0046] Determination of ammonia nitrogen concentration: Referring to standard HJ 195-2023, hypobromite oxidant was added to the water sample, and ammonia nitrogen was oxidized to an equal amount of nitrite nitrogen, which was further converted into nitrogen dioxide (NO2) gas in hydrochloric acid ethanol medium. NO2 was introduced into a gas phase molecular absorption spectrometer with a carrier gas (flow rate 0.1~0.2 L / min), and the absorbance was measured at the characteristic wavelength of 213.9 nm. The ammonia nitrogen concentration was calculated according to the calibration curve.
[0047] Determination of Chemical Oxygen Demand (COD) Concentration: Referring to standard HJ 828-2017, a known amount and excess of potassium dichromate standard solution were added to the water sample. In a strongly acidic medium, silver sulfate was used as a catalyst, and mercuric sulfate was added to mask chloride ions. The sample was heated and digested in a reflux apparatus for 2 hours to oxidize organic matter and some inorganic reducing substances in the water sample by potassium dichromate. After cooling, ferroin was used as an indicator, and the remaining potassium dichromate was titrated with ferrous ammonium sulfate standard solution. The equivalent oxygen content of the oxidized substances was calculated based on the amount of potassium dichromate consumed, and the COD concentration of the water sample was obtained.
[0048] The following uses total nitrogen removal efficiency as an example; other indicators can be calculated using the same formula. Total nitrogen removal efficiency is calculated using the following formula: ; in, Total nitrogen removal efficiency, The total nitrogen concentration (mg / L) in the effluent on day 0 (i.e., before the permeable concrete is added). The total nitrogen concentration (mg / L) in the effluent after 14 days of operation.
[0049] The test results for total nitrogen removal efficiency are as follows: Figure 3 As shown, the test results for total phosphorus removal efficiency are as follows: Figure 4 As shown in the figure, the test results for chemical oxygen demand removal efficiency are as follows: Figure 5 As shown in the figure, the test results for ammonia nitrogen removal efficiency are as follows: Figure 6 As shown.
[0050] The permeable concrete (uniform specifications; cylinders with a diameter of 10 cm and a height of 10 cm) prepared in Examples 1, 2, 1, 2 and 3 were placed in simulated sewage containing glyphosate pesticide residues after 28 days of standard curing. Operating under dynamic water flow conditions, effluent samples were collected on days 1, 3, 5, 7, and 14 to determine glyphosate removal efficiency. Referring to standard HJ 1071-2019, appropriate water samples were taken, and trisodium citrate dihydrate was added to complex metal ions at pH 4–9. After purification via solid-phase extraction or membrane filtration, sodium tetraborate solution and 9-fluorenylmethyl chloroformate (FMOC-Cl) acetonitrile solution were added, and derivatization was performed in a 40 °C water bath for 1 h. The derivatized solution was then extracted with dichloromethane to remove byproducts. The aqueous phase was filtered and separated using a high-performance liquid chromatograph (C18 reversed-phase column) equipped with a fluorescence detector. Qualitative analysis was performed using retention time and fluorescence characteristic wavelength, and quantitative analysis was performed using the external standard method to calculate the glyphosate concentration in the water sample, thus determining the removal rate. Results are as follows: Figure 7 As shown.
[0051] Figures 3 to 7 The results showed that Example 1 (bacterial agent mixing ratio 3:1) performed best in all pollutants (TN, TP, COD, NH4). + The removal efficiency of both glyphosate and N-methyl-N-methyl remained at the highest and most stable level. Meanwhile, the overall effect of the compound microbial group (Examples 1 and 2) was significantly better than that of the single-strain group (Comparative Examples 2 and 3) and the sterile group (Comparative Example 1), especially against recalcitrant organic pesticides such as glyphosate, indicating that the combination of Bacillus licheniformis ATCC® 14580 and Bacillus polymyxa ATCC® 842 formed a significant synergistic effect.
[0052] From the perspective of microbial degradation mechanisms, *Bacillus licheniformis* ATCC® 14580 initiates the oxidation reaction by secreting hydrolytic enzymes, producing small-molecule metabolites such as glyoxylates and organic acids, which provide metabolic substrates for *Bacillus polymyxa* ATCC® 842. *Bacillus polymyxa* ATCC® 842 secretes a large amount of extracellular polymers, promoting bacterial aggregation and biofilm formation, thus enhancing cell survival in high-pH, low-nutrient, and dynamic hydraulic scouring environments. A coupling mechanism of "metabolic complementarity + ecological synergy" is formed between the two bacteria, enabling them to exhibit highly efficient synergistic effects in the removal of complex nutrient and pesticide pollution. The porous structure of coral reef sand further provides a stable microenvironment, allowing microorganisms to obtain a long-term fixed growth space within the concrete, thereby ensuring the durability and stability of the degradation function.
[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing modified permeable concrete for pesticide remediation of riverbanks, characterized in that, include: Bacillus licheniformis and Bacillus polymyxa were revived and cultured to obtain Bacillus licheniformis bacterial suspension and Bacillus polymyxaformis bacterial suspension, and the Bacillus licheniformis bacterial suspension and Bacillus polymyxaformis bacterial suspension were mixed to obtain mixed bacterial suspension; Activated coral reef sand is obtained by pre-treating coral reef sand to activate it. Mix the mixed bacterial solution and activated coral reef sand, then solidify them to obtain dual-bacterial immobilized coral reef sand. The gel material, aggregate, nano-manganese dioxide, water, additives, and dual-bacterial immobilized coral reef sand are mixed, solidified, and cured to obtain modified permeable concrete.
2. The method for preparing modified permeable concrete for pesticide remediation of riparian zones according to claim 1, characterized in that, The viable bacteria concentration in the Bacillus licheniformis bacterial solution was 10. 5 ~10 7 CFU / mL, the viable bacterial concentration in the *Bacillus polymyxa* bacterial suspension is 10. 5 ~10 7 CFU / mL; The Bacillus licheniformis is ATCC® 14580, and the Bacillus polymyxa culture is ATCC® 842.
3. The method for preparing modified permeable concrete for pesticide remediation of riverbanks according to claim 1, characterized in that, In the process of mixing Bacillus licheniformis bacterial solution and Bacillus polymyxa bacterial solution to obtain mixed bacterial solution, the ratio of the number of viable bacteria in Bacillus licheniformis bacterial solution to the number of viable bacteria in Bacillus polymyxa bacterial solution is (1~3):
1.
4. The method for preparing modified permeable concrete for pesticide remediation of riverbanks according to claim 1, characterized in that, The activated coral reef sand has a particle size of 0.5~2 mm, a porosity of 35%~50%, and a specific surface area of not less than 20 m². 2 / g.
5. The method for preparing modified permeable concrete for pesticide remediation of riparian zones according to claim 1, characterized in that, The activation pretreatment of coral reef sand includes: The coral reef sand was soaked in a hydrochloric acid solution with a concentration of 0.1~0.5 mol / L for 2~4 h for acid washing. The coral reef sand was then removed and rinsed repeatedly with deionized water until neutral. The coral reef sand was then wetted and activated with sterile phosphate buffer and the pH was adjusted to 6.5~7.
5.
6. The method for preparing modified permeable concrete for pesticide remediation of riverbanks according to claim 1, characterized in that, The process of mixing and solidifying the mixed bacterial solution and activated coral reef sand to obtain dual-bacterial immobilized coral reef sand includes: The mixed bacterial solution and activated coral reef sand were mixed at a mass ratio of (1.2~5):
1. During the mixing process, the bacterial solution adsorption capacity was 15%~25%. Curing at 25~30 ℃ for 24~48 h yields dual-bacterial immobilized coral reef sand.
7. The method for preparing modified permeable concrete for pesticide remediation of riparian zones according to claim 1, characterized in that, In the process of mixing gel material, aggregate, nano manganese dioxide, water, additives and dual-bacterial immobilized coral reef sand, the additives include water-reducing agents and foaming agents; The mass fractions of each component are: 5-15 parts of double-bacterial immobilized coral reef sand, 120-230 parts of gel material, 270-350 parts of aggregate, 65-70 parts of water, 3-5 parts of water-reducing agent, 6-10 parts of foaming agent, and 2-4 parts of nano manganese dioxide. The gel material includes silica fume and cement, wherein the silica fume is 10-30 parts by mass and the cement is 180-220 parts by mass, and the cement is silicate cement. The aggregate is crushed stone with a particle size of 20-60 mm; The water-reducing agent is a polycarboxylate-based water-reducing agent; The foaming agent is a protein-based foaming agent; The nano-manganese dioxide has a particle size of 24-26 nm and a specific surface area of not less than 150 m². 2 / g.
8. The method for preparing modified permeable concrete for pesticide remediation of riverbanks according to claim 1, characterized in that, The process of mixing gel material, aggregate, nano-manganese dioxide, water, additives, and dual-strain immobilized coral reef sand includes: Add gelling material, aggregate, nano manganese dioxide, water, and additives, stir, and maintain the temperature at 20~35 ℃; Add the two-strain immobilized coral reef sand and stir for 10-20 minutes at a temperature of 20-35℃.
9. A modified permeable concrete for pesticide remediation of riverbanks, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 8.
10. The application of the modified permeable concrete according to claim 9, characterized in that, include: The modified permeable concrete is deployed in riverbank areas affected by non-point source pollution for in-situ synergistic removal of non-point source pollution. The non-point source pollution is one or more of nitrogen, phosphorus, and pesticides.