Water body remediation carbon sequestration and sink increase method based on lanthanum modified bentonite

Abstract

The invention discloses a water body remediation carbon sequestration and sink increasing method based on lanthanum modified bentonite, and belongs to the technical field of water body ecological remediation. Comprising the following steps: 1, isolating a to-be-restored water body, and obtaining current data of the water body; step 2, determining the current input amount of lanthanum modified bentonite and a flocculating agent based on the current data of the water body, and adding the lanthanum modified bentonite and the flocculating agent into the water body to repair the water body: blue-green algae on the surface of the water body settles, the settled blue-green algae die and decompose at the water bottom, and nutrient substances such as greenhouse gas nitrous oxide, methane and nitrogen and phosphorus are generated; aquatic plants are planted in the water body, the dissolved oxygen content of the water body is increased through photosynthesis of the aquatic plants, and release of greenhouse gases nitrous oxide and methane generated in the blue-green algae decomposition process in the second step is inhibited; in a water body environment where aquatic plants are planted, the lanthanum modified bentonite is used for locking phosphorus in a water body and bottom mud, the content of phosphorus in the water body and the bottom mud is reduced, and growth of algae is inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of water body ecological restoration, and in particular relates to a water body restoration and carbon fixation and sink enhancement method based on lanthanum modified bentonite. Background Art

[0002] With the acceleration of industrialization and the improvement of urbanization, the problem of eutrophication of water bodies has become increasingly serious, and blue algae blooms have occurred frequently. Traditional methods for treating blue algae blooms mainly include physical, chemical and biological methods. Physical methods such as salvage and aeration, although simple to operate, have limited effects and are difficult to fundamentally solve the problem. Although chemical methods can quickly reduce phosphorus content, they are prone to secondary pollution and have a negative impact on aquatic ecosystems. Although biological methods are environmentally friendly, they have a long treatment cycle and are greatly affected by environmental conditions.

[0003] Bentonite, as a natural mineral material, has good adsorption properties and has been widely used in the field of environmental pollution control. However, the adsorption capacity of unmodified bentonite for phosphorus is limited and it is difficult to meet the demand for efficient phosphorus reduction. Therefore, it is necessary to study a new and efficient cyanobacteria bloom control method based on bentonite. Summary of the invention

[0004] Purpose of the invention: In order to solve the above problems, the present invention provides a method for water body remediation and carbon fixation based on lanthanum-modified bentonite.

[0005] Technical solution: A method for water body restoration and carbon fixation based on lanthanum-modified bentonite, comprising the following steps: Step 1: Isolate the water body to be repaired and obtain current data of the water body; wherein the current data of the water body at least includes: physical parameter data, current pollutant data, and current blue algae data; Step 2: based on the current data of the water body, determine the current input amount of lanthanum-modified bentonite and flocculant, and add lanthanum-modified bentonite and flocculant into the water body for water body restoration: cyanobacteria on the surface of the water body settle, and the settled cyanobacteria die and decompose at the bottom of the water, producing greenhouse gases such as nitrous oxide, methane, and nutrients such as nitrogen and phosphorus; Step three, plant aquatic plants in the water body. The photosynthesis of aquatic plants increases the dissolved oxygen content in the water body, inhibiting the release of greenhouse gases nitrous oxide and methane produced by the decomposition process of cyanobacteria in step two. At the same time, in the water environment where aquatic plants are planted, lanthanum-modified bentonite is used to lock the phosphorus in the water body and bottom mud, inhibiting the growth of algae.

[0006] In a further embodiment, the following steps are also included: after the aquatic plants are planted and grown, the carbon fixation function of the aquatic plants is used to achieve carbon fixation and sink enhancement.

[0007] In a further embodiment, the following steps are also included: Regularly obtain new pollutant data and new cyanobacteria data of the water body to be restored; determine whether the ecological conditions of the water body are met based on the new pollutant data and the new cyanobacteria data, and obtain a judgment result: if not, execute steps 2 to 3 based on the judgment result.

[0008] In a further embodiment, if the judgment result is , , Then the new cyanobacteria data is updated to the current cyanobacteria data, and step 3 is executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

[0009] In a further embodiment, if the judgment result is , , Then the new pollutant data is updated to the current pollutant data, and steps 2 to 3 are executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

[0010] In a further embodiment, if the judgment result is , , Then the new pollutant data and the new cyanobacteria data are updated to the current pollutant data and the current cyanobacteria data respectively, and steps 2 to 3 are repeated.

[0011] In a further embodiment, the physical parameter data includes at least: the area and depth of the water body; The current pollutant data includes at least: dissolved phosphorus concentration; The current cyanobacteria data at least includes: the quantity of cyanobacteria.

[0012] In a further embodiment, the aquatic plants include but are not limited to one or more combinations of black algae, Vallisneria, and foxtail algae.

[0013] In a further embodiment, the preparation method of the lanthanum modified bentonite is as follows: Mixing and shaking: preparing a lanthanum chloride solution, and mixing the calcium-based bentonite and the lanthanum chloride solution according to a predetermined solid-liquid ratio to obtain a mixture, and shaking the mixture; Ion exchange: After the mixture is shaken, the mixture is centrifuged, and the supernatant is poured out after centrifugation to obtain a precipitate; according to a predetermined solid-liquid ratio, the lanthanum chloride solution is added to the precipitate again, and the mixing and shaking process is repeated, and the mixture is centrifuged after shaking, and the supernatant is poured out to obtain a precipitate after cation exchange; Washing and drying: The cation exchange precipitate is washed with distilled water and centrifuged; the cation exchange precipitate is then dried and ground to obtain lanthanum-modified bentonite.

[0014] The present invention isolates the water body to be repaired and obtains detailed current data of the water body, including physical parameter data, current pollutant data and current cyanobacteria data. Based on these data, the input amount of lanthanum-modified bentonite and flocculant can be accurately determined to achieve effective sedimentation of cyanobacteria on the surface of the water body, thereby reducing the harm of cyanobacteria to the water body from the source, such as reducing water hypoxia and water quality deterioration caused by excessive reproduction of cyanobacteria.

[0015] Lanthanum-modified bentonite is used to lock phosphorus in water bodies and bottom sediments, reduce the phosphorus content in water bodies and bottom sediments, inhibit the growth of algae, effectively control the key factors of eutrophication of water bodies, prevent secondary outbreaks of algae, and achieve a virtuous cycle of the water ecosystem.

[0016] When blue algae settle and decompose to produce greenhouse gases such as nitrous oxide and methane, planting aquatic plants and utilizing their photosynthesis to increase the dissolved oxygen content in the water can inhibit the release of nitrous oxide and methane, which will help reduce greenhouse gas emissions and have positive significance for alleviating global climate change. At the same time, it will improve the ecological environmental quality of water bodies and provide a more suitable living environment for aquatic organisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a picture of water plants planted after flocculation and sedimentation of cyanobacteria on bentonite modified with lanthanum.

[0018] Figure 2 This is a picture of the water planted after flocculation and sedimentation of cyanobacteria by bentonite modified without the addition of lanthanum.

[0019] Figure 3 It is calcium-based bentonite and lanthanum-modified bentonite. X X-ray diffraction comparison chart.

[0020] Figure 4 Lanthanum modified bentonite at 20000 x Under magnification SEM picture.

[0021] Figure 5 is the result under different initial orthophosphate concentration conditions LMB Adsorption kinetics.

[0022] Figure 6is the orthophosphate adsorption isotherm of lanthanum-modified bentonite.

[0023] Figure 7 This is a schematic diagram of the phosphorus fixation and sediment passivation by lanthanum-modified bentonite and submerged plants. DETAILED DESCRIPTION

[0024] Example 1 This embodiment discloses a water body restoration, carbon fixation and sink enhancement method based on lanthanum-modified bentonite, which is applicable to all eutrophic water bodies. In this example, a project in Suzhou is taken as an example for detailed description. The total phosphorus in Xiangmu Lake is 0.19 mg / L, which is Class V according to the lake and reservoir standards, and is close to the threshold of Class V water of 0.2 mg / L, which is far higher than the "Lake Nutrient Benchmark-Central and Eastern Lakes (Total Phosphorus, Total Nitrogen, Chlorophyll a) (2020 Edition)". The TP benchmark value of 0.029 mg / L for healthy lakes. The water quality of Xiangmu Lake is mainly affected by organic phosphorus and cyanobacteria. In order to control the water quality of Xiangmu Lake. The following steps are included: Step 1: Isolate the water body to be repaired and obtain current data of the water body; wherein the current data of the water body at least includes: physical parameter data, current pollutant data, and current blue algae data; First, in order to efficiently restore the water body, Xiangmu Lake was divided and isolated into small lakes. The area of ​​the divided lakes is 100 m 2 , 200 m 2 , 300 m 2 , or other number of areas. The isolation method can be used to separate several 100 diameter mm Left and right, thickness 3~6 mm The corrosion-resistant steel pipes are used as fixed piles, and each steel pipe is inserted into the hard layer of the lake bottom every 2 to 30 meters along the edge of the water body to be repaired; the steel pipe is inserted into the hard layer at least 1 m The height of the top of the steel pipe above the water surface to be repaired is greater than 0.6 m . Connect the top and middle of the steel pipe horizontally with steel cables through buckles to form a fence structure. Select waterproof canvas with a water resistance of more than 5 years as the fence cloth, and fix the fence cloth to the inner side of the fence structure through steel cables so that the fence cloth completely surrounds the water area to be repaired. The connection between the fence cloths can be interlocked and sutured with stainless steel sheets. The water blocking height of the fence cloth exceeds 0.6 m As described above, the bottom end of the enclosure cloth is connected to the bottom of the water body, so that the water body inside the enclosure is completely isolated from the water body outside the enclosure during the entire restoration process.

[0025] Cyanobacteria blooms and lake total phosphorus ( TP )、Dissolved phosphorus( SRP) concentrations show a significant positive correlation. In eutrophic lakes, the phosphorus concentration in the water body and the outbreak of cyanobacteria are mutually causal. Therefore, after the water body to be repaired is isolated, the current data of the water body is measured. Such as physical parameter data: the area and depth of the water body. Current pollutant data: total phosphorus concentration and dissolved phosphorus concentration. Current cyanobacteria data: the number of cyanobacteria, the microscopic morphology of cyanobacteria, the photosynthetic activity of cyanobacteria, and chlorophyll a concentration.

[0026] Step 2: Based on the current data of the water body, determine the current input amount of lanthanum-modified bentonite and flocculant, and add lanthanum-modified bentonite and flocculant into the water body for water body repair: cyanobacteria on the surface of the water body settle, and the settled cyanobacteria die and decompose at the bottom of the water, producing greenhouse gases such as nitrous oxide, methane, and nutrients such as nitrogen and phosphorus; first, spread the lanthanum-modified bentonite evenly on the surface of the water body, and try to ensure that it is evenly dispersed during the spreading process to ensure full contact with the water body. Subsequently, dissolve polyaluminum chloride in an appropriate amount of clean water according to a certain proportion, prepare a solution, and evenly spray it on the surface of the water body through a spray device.

[0027] After adding the agent, mix it with the water thoroughly. After a few hours, you can see that the blue algae on the surface of the water gradually condense into clumps and begin to sink. As time goes by, most of the blue algae sink to the bottom of the water.

[0028] The cyanobacteria that settled to the bottom of the water began to decompose under the action of microorganisms. The gas components produced during the decomposition process were monitored in real time by gas monitoring equipment installed at the bottom of the water. It was found that as the cyanobacteria decomposed, the concentration of the greenhouse gas nitrous oxide gradually increased. Within 24 hours after the cyanobacteria began to decompose, the concentration of nitrous oxide increased from the initial near zero to 50ppb (parts per billion), and in the subsequent period of time, as the cyanobacteria continued to decompose, its concentration continued to rise. This shows that the cyanobacteria decomposed at the bottom of the water after settling produced a significant amount of the greenhouse gas nitrous oxide, which further highlights the need to take subsequent measures to suppress its release.

[0029] Step three, planting aquatic plants in the water body. The photosynthesis of the aquatic plants increases the dissolved oxygen content in the water body, inhibiting the release of greenhouse gases nitrous oxide and methane produced by the decomposition process of cyanobacteria in step two. At the same time, in the water environment where the aquatic plants are planted, lanthanum-modified bentonite is used to lock the phosphorus in the water body and the bottom mud, thereby reducing the phosphorus content in the water body and the bottom mud and inhibiting the growth of algae.

[0030] It also includes the following steps: After the aquatic plants are planted and grown, the carbon fixation function of the aquatic plants is utilized to achieve carbon fixation and sink enhancement.

[0031] After confirming that the blue algae have settled to the bottom of the water in large quantities and have begun to decompose, water plants are planted. Considering the eutrophication level, water depth, and light conditions of the pond, it was decided to plant a combination of black algae, Vallisneria salsa, and foxtail algae to give full play to the synergistic effect of different water plants in water body restoration. The planting ratio is black algae: Vallisneria salsa: foxtail algae = 3:2:2, and the total planting area accounts for 40% of the pond surface area.

[0032] In the early stage of planting, nutrient soil is laid at the bottom of the pond to provide sufficient nutrients for the growth of aquatic plants. At the same time, oxygenation equipment is set up to maintain the dissolved oxygen content in the water at around 5mg / L to ensure that aquatic plants have a good growth environment during the adaptation period.

[0033] As the water plants grow, their photosynthesis gradually increases. By setting up multiple dissolved oxygen monitoring points in the water body, the changes in dissolved oxygen in the water body are monitored in real time. Within a week after planting the water plants, the dissolved oxygen content in the water body gradually increased from the initial 5mg / L to 7mg / L, and stabilized between 7-8mg / L in the following two weeks.

[0034] At the same time, the concentration of nitrous oxide in the water was continuously monitored using a gas chromatography-mass spectrometer (GC-MS). The results showed that before the planting of aquatic plants, the concentration of nitrous oxide produced by the decomposition of cyanobacteria continued to rise, reaching 80ppb. Within a week after the planting of aquatic plants, the rising trend of nitrous oxide concentration was significantly suppressed. After two weeks, the concentration of nitrous oxide began to slowly decline, and after three weeks it dropped to 60ppb. This shows that aquatic plants effectively inhibit the release of greenhouse gas nitrous oxide during the decomposition of cyanobacteria by increasing the amount of dissolved oxygen in the water.

[0035] In the water environment where aquatic plants are planted, lanthanum-modified bentonite continues to lock phosphorus in the water and sediment. Water samples were collected regularly and the phosphorus content in the water was determined by ammonium molybdate spectrophotometry. In the early stage of planting aquatic plants, the concentration of dissolved phosphorus in the water was 0.2 mg / L. With the continuous locking of phosphorus by lanthanum-modified bentonite and the absorption of phosphorus by aquatic plants, the phosphorus content gradually decreased. Within one month, the concentration of dissolved phosphorus in the water dropped to 0.08 mg / L, which is lower than the critical value (0.1 mg / L) for eutrophication of general water bodies.

[0036] The growth of algae in the water was monitored by microscopic observation and algae counting methods. The results showed that as the phosphorus content decreased, the growth of algae was significantly inhibited. After one month of planting aquatic plants and lanthanum-modified bentonite, the number of algae decreased by 60% compared with before planting, the water transparency increased from 20cm before planting to 40cm, and the water color gradually changed from the original blue-green to light green, and the water ecological environment was significantly improved.

[0037] In summary, in this embodiment, by planting aquatic plants and utilizing the synergistic effect of lanthanum-modified bentonite, not only the release of nitrous oxide produced by the decomposition of cyanobacteria is effectively inhibited, but also the phosphorus content in the water is reduced, the growth of algae is inhibited, and the water environment of the eutrophic pond is significantly improved.

[0038] In order to grasp the progress and effect of water body restoration in real time, the following steps are further included: regularly obtaining new pollutant data and new cyanobacteria data of the water body being restored; judging whether the water body ecological conditions are met based on the new pollutant data and the new cyanobacteria data, and obtaining a judgment result: if not met, executing steps two to three based on the judgment result.

[0039] In other words, after a period of time of planting aquatic plants and using lanthanum-modified bentonite to repair the water body, regular monitoring of the water body begins to determine whether the water body has reached the ideal ecological conditions. The monitoring cycle is set to once a week to obtain new pollutant data (mainly focusing on dissolved phosphorus concentration) and new cyanobacteria data (the number of cyanobacteria) of the repaired water body.

[0040] Further expressed as if the judgment result is , , Then the new cyanobacteria data is updated to the current cyanobacteria data, and step 3 is executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

[0041] If the judgment result is , , Then the new pollutant data is updated to the current pollutant data, and steps 2 to 3 are executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

[0042] If the judgment result is , , Then the new pollutant data and the new cyanobacteria data are updated to the current pollutant data and the current cyanobacteria data respectively, and steps 2 to 3 are repeated.

[0043] For example, during a certain monitoring, the new dissolved phosphorus concentration was measured to be 0.09 mg / L through professional testing equipment and methods, and the new number of blue algae was tested to contain 8*10 6 Cyanobacterial cells.

[0044] The water pollutant threshold is set at 0.1 mg / L and the blue algae threshold is set at 5*10 6 Pieces / liter.

[0045] Based on this judgment result, the new cyanobacteria data is updated to the current cyanobacteria data, and then step three is executed, that is, continue to pay attention to the growth of aquatic plants, and adjust the aquatic plant maintenance measures in time by regularly testing the dissolved oxygen content, pH value and other indicators of the water body, such as applying appropriate amounts of fertilizers to ensure the nutrient needs of aquatic plants, promote better growth of aquatic plants, further inhibit the release of nitrous oxide produced by the decomposition of cyanobacteria, and use lanthanum-modified bentonite to continue to lock phosphorus in the water and bottom mud to inhibit algae growth.

[0046] By regularly acquiring data, making judgments, and performing corresponding operations based on the results, the water body can be repaired and optimized continuously until the pollutant data and blue algae data of the water body meet the set water body ecological conditions. Figure 1 and Figure 2 As shown, Figure 1 This is a picture of water grass planted after flocculation and sedimentation of cyanobacteria by lanthanum-modified bentonite. Figure 2 This is a picture of water grass planted after flocculation and sedimentation of cyanobacteria by bentonite modified with lanthanum. By comparing the two pictures, it can be found that the growth of water grass with lanthanum-modified bentonite as a phosphorus lock agent is indeed significantly better than the growth of bentonite modified without lanthanum.

[0047] Example 2 This embodiment is to implement the method described in Example 1, and discloses a method for preparing lanthanum-modified bentonite (hereinafter referred to as the preparation method), comprising the following steps: Physical purification Calcium-based bentonite is added to distilled water to prepare a slurry with a solid-liquid ratio of 1:10. The slurry is placed in an ultrasonic cleaning device, ultrasonically vibrated at a frequency of 20-40 kHz for 10-30 minutes, and centrifuged and dried after being allowed to settle for 30 minutes to complete the physical purification of the bentonite.

[0048] Mix and shake Weigh 37.14 g of 7 H 2 O · LaCl 3 , dissolved in a certain amount of distilled water, with 1000 ml Make up to volume with a volumetric flask and prepare 0.1 mol / L of Lacl 3 Solution; weigh 10 g Calcium bentonite (purity 90%) and 1000 ml 0.1 mol / L of LaCl 3 The solution was mixed in an acid-washed plastic container at a solid-liquid ratio of 1:100 and the container was placed on a shaker (shaking condition was 200 rpm ,twenty four h ).

[0049] Ion Exchange Shake well 24 h Then, the mixture was centrifuged at 4000 rpm , 10 min ), after centrifugation, pour out the supernatant to obtain the precipitate, and add 1000% of the precipitate again at a solid-liquid ratio of 1:100. ml 0.1 mol / L of LaCl 3 The solution was mixed and shaken repeatedly, centrifuged after shaking, and the supernatant was poured out to obtain the precipitate after cation exchange.

[0050] Step 3: Wash and dry The cation exchange precipitate was washed with distilled water and centrifuged (centrifugation conditions were 4000 rpm , 10 min ) 3~4 times to ensure that the unexchanged residual La Ions (with AgCl Detection); then pour 50 ml The centrifuge tube was placed in a constant temperature air drying oven and dried at 60 °C for 24 h After grinding with a mortar, lanthanum-modified bentonite ( LMB ), store in a sealed bottle at room temperature for later use.

[0051] The preparation method adopts ion exchange method to prepare lanthanum modified bentonite, and uses XRD , SEM A variety of analytical methods are used to characterize the changes in structure, appearance, and functional groups of bentonite before and after modification, such as Figures 3 to 7 In addition, the adsorption test of phosphate on the lanthanum-modified bentonite prepared by this preparation method was carried out to explore its adsorption performance and mechanism, and the following results were obtained: (1) In this preparation method, La 3+ Loading onto calcium-based bentonite improves adsorption performance; XRD The characterization results show that calcium-based bentonite La After element modification, the interlayer spacing is changed from 1.524 nm becomes 1.568 nm ,exist d 300 , d302 , d 304 The diffraction peaks of lanthanum carbonate, lanthanum oxide and lanthanum hydroxide appeared in the La After element doping and modification, the bentonite unit cell parameters and the interplanar spacing become larger; SEM - EDS The characterization results show that the lamellar structure of the modified bentonite has not changed significantly, but due to the drying step and La 3+ After doping and modification, the bentonite particles are more dispersed, the surface is rougher, and the adsorption performance is enhanced; ICP , XRF The characterization results show that La 3+ Between the calcium-based bentonite layer Ca 2+ A cation exchange reaction occurs. La Elements are loaded on bentonite. La The content of the element is about 8.46%.

[0052] (2) LMB It efficiently fixes phosphate ions in water by chemical adsorption (monolayer adsorption, ionic bond form). LMB The adsorption kinetics and isotherms of orthophosphoric acid were studied. The adsorption kinetics fitting results showed that LMB The adsorption kinetics conformed to the pseudo-second-order kinetic model. The adsorption process was mainly chemical adsorption. The initial concentration of orthophosphate was 25 and 50 mg / L The theoretical equilibrium adsorption capacity q e ( cal ) are 18.55 and 19.84 mg / L The adsorption isotherm fitting results show that LMB The adsorption process of orthophosphoric acid is more consistent with Langmuir Adsorption isotherm model ( R 2 =0.9971), the adsorption process is monolayer adsorption, at 25℃, LMB Theoretical maximum adsorption capacity for orthophosphate Q m ( cal ) is 24.27 mg / g .

Claims

1. A method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite, characterized in that: The following steps are involved: Step 1: Isolate the water body to be repaired and obtain current data of the water body; wherein the current data of the water body at least includes: physical parameter data, current pollutant data, and current blue algae data; Step 2: based on the current data of the water body, determine the current input amount of lanthanum-modified bentonite and flocculant, and add lanthanum-modified bentonite and flocculant into the water body for water body restoration: cyanobacteria on the surface of the water body settle, and the settled cyanobacteria die and decompose at the bottom of the water, producing greenhouse gases such as nitrous oxide, methane, and nutrients such as nitrogen and phosphorus; Step three, plant aquatic plants in the water body. The photosynthesis of aquatic plants increases the dissolved oxygen content in the water body, inhibiting the release of greenhouse gases nitrous oxide and methane produced by the decomposition process of cyanobacteria in step two. At the same time, in the water environment where aquatic plants are planted, lanthanum-modified bentonite is used to lock the phosphorus in the water body and bottom mud, inhibiting the growth of algae.

2. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 1, characterized in that: The following steps are also included: After the aquatic plants are planted and grow, their carbon fixation function is utilized to achieve carbon fixation and carbon sink enhancement.

3. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 1, characterized in that: The following steps are also included: Regularly obtain new pollutant data and new cyanobacteria data of the water body to be restored; determine whether the ecological conditions of the water body are met based on the new pollutant data and the new cyanobacteria data, and obtain a judgment result: if not, execute steps 2 to 3 based on the judgment result.

4. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 3, characterized in that: If the judgment result is , , Then the new cyanobacteria data is updated to the current cyanobacteria data, and step 3 is executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

5. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 3, characterized in that: If the judgment result is , , Then the new pollutant data is updated to the current pollutant data, and steps 2 to 3 are executed; wherein, For new pollutant data, is the water pollutant threshold; For new cyanobacteria data, is the blue-green algae threshold in water bodies.

6. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 3, characterized in that: If the judgment result is , , Then the new pollutant data and the new cyanobacteria data are updated to the current pollutant data and the current cyanobacteria data respectively, and steps 2 to 3 are repeated.

7. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 1, characterized in that: The physical parameter data includes at least: the area and depth of the water body; The current pollutant data includes at least: dissolved phosphorus concentration; The current cyanobacteria data at least includes: the quantity of cyanobacteria.

8. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 1, characterized in that: The aquatic plants include but are not limited to one or more combinations of black algae, Vallisneria, and foxtail algae.

9. The method for water body restoration and carbon fixation and sink enhancement based on lanthanum-modified bentonite according to claim 1, characterized in that: The preparation method of the lanthanum modified bentonite is as follows: Physical purification: Bentonite is purified by physical methods such as ultrasonic washing and centrifugal separation to remove impurities and disperse particles on the surface of calcium-based bentonite, thereby improving its cation exchange capacity and performance; Mixing and shaking: preparing a lanthanum chloride solution, and mixing the calcium-based bentonite and the lanthanum chloride solution according to a predetermined solid-liquid ratio to obtain a mixture, and shaking the mixture; Ion exchange: After the mixture is shaken, the mixture is centrifuged, and the supernatant is poured out after centrifugation to obtain a precipitate; according to a predetermined solid-liquid ratio, the lanthanum chloride solution is added to the precipitate again, and the mixing and shaking process is repeated, and the mixture is centrifuged after shaking, and the supernatant is poured out to obtain a precipitate after cation exchange; Washing and drying: The cation exchange precipitate was washed with distilled water and centrifuged; Subsequently, the precipitate after the cation exchange is dried and ground to obtain lanthanum-modified bentonite.

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