A targeted treatment material for river and lake sediment pollutants and a preparation method thereof

Abstract

The application discloses a kind of for river and lake bottom mud pollutant targeted treatment material and preparation method thereof, it is related to river and lake bottom mud pollutant processing technical field.The preparation method of the application includes the following steps: first, activated biochar is dry mixed with sodium alginate, functionalized modified attapulgite, to prepare premix dry powder;Then, in 35-40 DEG C deionized water, add sodium alginate, sodium carboxymethyl cellulose and stir evenly, after cooling, add premix dry powder and stir evenly, then, at 4 DEG C, stand for 30-50 min, then add double-layer embedding microcapsule, after stirring, drop into calcium chloride aqueous solution and crosslinking solidification 4-5h, then take out the granules, wash, freeze-drying, to obtain the targeted treatment material for river and lake bottom mud pollutant.The introduction of functionalized modified attapulgite, double-layer embedding microcapsule and other raw materials in the application, while improving the targeting accuracy, effective utilization rate and composite pollution synergistic management ability.

Description

Technical Field

[0001] This invention relates to the field of river and lake sediment pollutant treatment technology, specifically to a targeted treatment material for river and lake sediment pollutants and its preparation method. Background Technology

[0002] River and lake sediments are important reservoirs and potential sources of internal pollutants in water bodies. The complex accumulation of various pollutants, including heavy metals, nitrogen and phosphorus nutrients, and persistent organic matter, continuously hinders water quality improvement and ecological restoration. In-situ targeted remediation technology, due to its minimal construction disturbance and high environmental compatibility, has become an important technical approach for treating internal pollution in sediments. Functional treatment materials with directional action capabilities are the core support for this technology.

[0003] However, in practical applications, existing targeted treatment materials for pollutants in river and lake sediments still have the following performance defects: First, insufficient targeting precision. Most materials rely on passive diffusion and contact adsorption to function, lacking the ability to directionally migrate and identify target pollutants in sediment pores. They are easily consumed non-specifically by humus and inert particulate matter in the sediment, and have weak penetration into deep sediments. Second, low effective utilization rate. After the materials are added, they are prone to agglomeration and sedimentation, and a large number of internal active sites are encapsulated and shielded. At the same time, the complex composition of sediments can easily cause rapid passivation of the material surface, and the reactivity will significantly decrease in a short period of time. Third, weak ability to synergistically treat complex pollution. Existing materials are mostly developed for single pollution types. For complex pollution systems where heavy metals, nitrogen, phosphorus, and organic matter coexist, it is difficult to achieve synergistic treatment of multiple pollutants simultaneously. The combination of multiple materials is also prone to performance antagonism and mutual interference.

[0004] Therefore, the targeting accuracy, effective utilization rate, and synergistic treatment capabilities of existing targeted treatment materials for pollutants in river and lake sediments still need to be improved simultaneously. Summary of the Invention

[0005] The purpose of this invention is to provide a targeted treatment material for pollutants in river and lake sediments and its preparation method, thereby solving the following technical problems:

[0006] Existing targeted treatment materials for pollutants in river and lake sediments still suffer from poor targeting accuracy, low utilization rate, and limited ability to synergistically treat complex pollution involving heavy metals, nitrogen, phosphorus, and organic matter.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for preparing a targeted treatment material for pollutants in river and lake sediments includes the following steps:

[0009] S1: Dry mix activated biochar with sodium alginate and functionalized modified attapulgite for 10-15 minutes to obtain premixed dry powder;

[0010] S2: Add sodium alginate and sodium carboxymethyl cellulose to deionized water at 35-40℃ and stir for 20-30 minutes. After cooling to 25-35℃, add premixed dry powder and stir for 30-40 minutes. Then let it stand at 4℃ for 30-50 minutes. Add double-layer embedded microcapsules, stir, and drop into calcium chloride aqueous solution and crosslink and solidify for 4-5 hours. Then take out the particles, wash, freeze dry, and obtain a targeted treatment material for pollutants in river and lake sediment.

[0011] The activated biochar is rice husk biochar that has been activated by soaking in hydrochloric acid.

[0012] The functionalized modified attapulgite is prepared by first washing and purifying sodium-based attapulgite with deionized water, then reacting it with 3-mercaptopropyltriethoxysilane, then reacting it with vinylphosphonic acid under ultraviolet light, and finally reacting it with ferric chloride hexahydrate, sodium hydroxide, and lanthanum nitrate hexahydrate to support a lanthanum iron-iron composite hydroxide.

[0013] The double-layer encapsulated microcapsules are prepared by first encapsulating nano-calcium peroxide in paraffin, and then encapsulating it with a bacterial suspension of river and lake sediment acclimatization bacteria in a sodium alginate-chitosan double layer and cross-linking and solidifying it.

[0014] Preferably, the mass ratio of activated biochar, sodium alginate, and functionalized modified attapulgite in S1 is 45-55: 2-2.5: 25-30;

[0015] The ratio of deionized water, sodium alginate, sodium carboxymethyl cellulose, premixed dry powder, double-layer encapsulated microcapsules, and calcium chloride aqueous solution in S2 is 180-220mL: 3-3.5g: 2-2.5g: 72-87.5g: 40-50g: 200-250mL;

[0016] The mass fraction of the calcium chloride aqueous solution in S2 is 3.5%.

[0017] Preferably, the method for preparing the activated biochar is as follows:

[0018] Rice husk biochar was washed with water until the pH of the filtrate was 6.6-7.2 and then dried. After that, it was soaked in hydrochloric acid aqueous solution for 12-14 hours to activate it. Then it was washed with water, dried, and sieved to obtain activated biochar.

[0019] Preferably, the ratio of rice husk biochar to hydrochloric acid aqueous solution is 50-60g: 200-220mL;

[0020] The concentration of the hydrochloric acid aqueous solution is 1 mol / L.

[0021] Preferably, the method for preparing the functionalized modified attapulgite is as follows:

[0022] A1: Add sodium-based attapulgite to deionized water and ultrasonically disperse for 60-80 min. Then let it stand and settle for 60-80 min and discard the lower layer impurities. Centrifuge the upper layer suspension at 6000 r / min for 10-20 min. Then take the lower layer precipitate, dry, grind and sieve it to obtain purified attapulgite.

[0023] A2: Add 3-mercaptopropyltriethoxysilane to a mixed solvent of anhydrous ethanol 1 and deionized water and adjust the pH to 4.3-4.5. Stir for 30-50 min, then add purified attapulgite and ultrasonically disperse for 60-80 min. Then stir at 50℃ under a nitrogen atmosphere for 6-7 h, then centrifuge, wash the precipitate, and finally disperse it in anhydrous ethanol 2 to obtain a mercaptolated attapulgite dispersion.

[0024] A3: Under a nitrogen atmosphere, vinylphosphonic acid and 2,2-dimethoxy-2-phenylacetophenone were added to the mercapto-modified attapulgite dispersion and stirred for 20-30 min. Then, the mixture was reacted under 100W, 365nm UV irradiation for 4-5 h. After centrifugation, the precipitate was washed, dried, and then dispersed in deionized water. Ferric chloride hexahydrate was added and stirred for 30-50 min. The pH was then adjusted to 4.3-4.7 under a nitrogen atmosphere and stirred for 90-100 min. Lanthanum nitrate hexahydrate was added and stirred for 20-30 min. The pH was adjusted to 7.3-7.7 and stirred for 2 h. Finally, the mixture was centrifuged, washed, dried, ground, and sieved to obtain the functionalized modified attapulgite.

[0025] Preferably, the mass ratio of deionized water to sodium-based attapulgite in A1 is 330-350:25;

[0026] The ratio of anhydrous ethanol 1, deionized water, 3-mercaptopropyltriethoxysilane, purified attapulgite, and anhydrous ethanol 2 in A2 is 275mL:25mL:13-15mL:20-24g:200mL.

[0027] The ratio of the amount of mercaptolated attapulgite dispersion, vinylphosphonic acid, 2,2-dimethoxy-2-phenylacetophenone, deionized water, ferric chloride hexahydrate, and lanthanum nitrate hexahydrate in A3 is 200mL: 6-7g: 0.09-0.11g: 250-300mL: 13.5-16.1g: 2.25-2.65g.

[0028] Preferably, the preparation method of the double-layer encapsulated microcapsules is as follows:

[0029] B1: Add deionized water to the target river and lake sediment and shake for 2 h. Then centrifuge and take the supernatant. Filter the supernatant through a 0.22 μm filter membrane to obtain sediment leachate.

[0030] B2: Add sterile LB medium to the target river and lake sediment and enrich it at 25℃ and 150 r / min for 72 h. Then add sediment leachate for three generations of acclimatization treatment. Centrifuge at 8000 r / min for 10-12 min, collect the bacterial cells, resuspend them in sterile physiological saline, add trehalose, and adjust OD. 600 After reaching 1.2, a bacterial suspension was obtained;

[0031] B3: Heat paraffin to 60℃ to melt and add Span-80. Stir at 58-60℃ for 20-30 min, then add nano calcium peroxide and stir for 10-20 min to obtain a wax phase dispersion.

[0032] B4: Add Tween-80 to anhydrous ethanol and stir for 10-20 min. Then cool to 0-4℃ and add the wax phase dispersion while stirring. Stir for 10-15 min, then filter, wash, and air dry in the dark for 2-4 h to obtain core microspheres.

[0033] B5: Add chitosan to deionized water and stir for 20-30 minutes, then add glacial acetic acid and stir for 10-20 minutes, then adjust the pH to 5.0-5.5 to obtain a chitosan solution;

[0034] B6: Add sodium alginate to deionized water and stir for 20-30 minutes. After cooling to 3-5℃, add the core microspheres and bacterial suspension and stir for 8-10 minutes. Then drop it into a calcium chloride aqueous solution at 3-5℃. After cross-linking and curing at 3-5℃ for 2 hours, filter and wash. Then immerse it in a chitosan solution at 3-5℃ and stir for 10-15 minutes. Filter, wash and dry until the water content is 40%-60% to obtain double-layer embedded microcapsules.

[0035] Preferably, the ratio of deionized water added to the target river and lake sediment described in B1 is 200g: 500-550mL;

[0036] The ratio of the target river and lake sediment, sterile LB medium, sterile physiological saline, and trehalose described in B2 is 500g:1000mL:100-120mL:1-1.2g;

[0037] The mass fraction of the sterile saline solution described in B2 is 0.9%;

[0038] In the three-generation acclimatization treatment described in B2, the volume ratio of LB medium to sediment leachate for the first generation was 2:1, the volume ratio of LB medium to sediment leachate for the second generation was 1:1, and the volume ratio of LB medium to sediment leachate for the third generation was 1:2, with each generation cultured for 48 hours.

[0039] The ratio of paraffin, Span-80, and nano-calcium peroxide described in B3 is 18-20g: 3-3.4mL: 12-14g.

[0040] Preferably, the ratio of anhydrous ethanol, Tween-80, and wax phase dispersion in B4 is 600mL: 3-3.4mL: 33-37g;

[0041] The ratio of deionized water, chitosan, and glacial acetic acid used in B5 is 300-350mL: 9-10g: 6-7mL;

[0042] The ratio of deionized water, sodium alginate, kernel microspheres, bacterial suspension, calcium chloride aqueous solution, and chitosan solution in B6 is 300-350mL: 6-7g: 27-30g: 120mL: 600-700mL: 300-350mL;

[0043] The mass fraction of the calcium chloride aqueous solution described in B6 is 2%.

[0044] The beneficial effects of this invention are:

[0045] This invention provides a targeted treatment material for pollutants in river and lake sediments and its preparation method. The invention improves the targeting accuracy, effective utilization rate, and synergistic treatment capability of the targeted treatment material for pollutants in river and lake sediments through the following method.

[0046] (1) The functionalized modified attapulgite of this invention is prepared by three steps: mercaptosilanization, thiol-ene click grafting of phosphonic acid, and loading of iron-lanthanum hydroxide. Among them, the purified attapulgite can achieve broad-spectrum adsorption by relying solely on surface ion exchange, but it has no selective preference for lead and cadmium. The mercapto and phosphonic acid groups introduced after modification have a stronger chelating affinity for lead ions, which can significantly improve the lead / cadmium adsorption selectivity and achieve targeted enrichment of heavy metals. The anchored iron-lanthanum hydroxide has a specific coordination effect on phosphate, which targets and enhances the adsorption and fixation of phosphorus. The covalently grafted functional groups are firmly bound and are not easy to dissolve and fall off in the water environment, avoiding ineffective loss of adsorption sites. The high density of specific adsorption sites can significantly increase the adsorption capacity per unit mass of material, reduce the dosage threshold, and improve the utilization efficiency of adsorbed components. At the same time, rapid passivation of heavy metals can reduce their toxicity to functional microorganisms, indirectly improving the effective efficiency of the bacterial agent. The functionalized modified attapulgite of this invention has basic passivation functions for heavy metals and phosphorus, which is the chemical basis for the treatment of complex pollution. At the same time, it can reduce the biotoxicity of heavy metals, adsorb and enrich pollutants to increase local concentration, create a low-toxicity, high-matrix microenvironment for microbial degradation, and strengthen the linkage effect between chemical adsorption and biodegradation.

[0047] (2) The double-layer encapsulated microcapsules of this invention are prepared with a core of paraffin encapsulating nano-calcium peroxide and an outer layer of sodium alginate-chitosan encapsulating functional bacteria. The double-layer hydrogel shell can resist external environmental impacts, protecting the acclimatized native bacteria as they slowly release oxygen after reaching the target site in the sediment, thus increasing the colonization rate of the bacteria in the sediment. The slowly released oxygen can form a local aerobic microenvironment at the sediment interface, directionally activating aerobic degradative bacteria and achieving targeted bioremediation. The hydrophobic paraffin core can control the decomposition rate of calcium peroxide, avoiding rapid release and waste upon contact with water, significantly extending the action period of the oxygen source, and improving the effective utilization rate of oxygen. The double-layer hydrogel encapsulation can reduce bacterial inactivation during preparation, storage, and addition, increasing bacterial survival rate and avoiding ineffective bacterial loss. The double-layer encapsulation structure can isolate external temperature, humidity, and other microbial interference, significantly reducing the rate of bacterial activity decay during room temperature storage and extending the shelf life of the material. The paraffin layer isolates moisture contact, preventing premature decomposition of calcium peroxide and ensuring stable slow-release performance during storage. Its continuously released oxygen provides an aerobic environment for nitrifying bacteria and aerobic degrading bacteria, significantly improving the removal efficiency of total nitrogen and organic matter; the oxidizing environment can promote the conversion of heavy metals to stable high valence states, assisting chemical adsorption to enhance the passivation effect of heavy metals; at the same time, it inhibits anaerobic phosphorus release from the sediment, and works synergistically with adsorption components to remove phosphorus.

[0048] (3) In the activated biochar of this invention, the porous structure generated after activation with hydrochloric acid can enrich pollutants in the aquatic environment, increase the local pollutant concentration of the material, and assist the targeted adsorption of functionalized attapulgite; at the same time, it provides pore sites for functional bacteria to attach and colonize, improves the colonization efficiency of bacteria on the material surface, and indirectly enhances biological targeting. It can avoid the agglomeration of functionalized attapulgite powder, allowing more adsorption sites to be exposed to the aquatic environment, and improving the effective utilization rate of adsorbed components; at the same time, as a carrier for microbial immobilization, it reduces the loss of bacteria caused by water flow, prolongs the action time of bacteria, and improves the utilization efficiency of bacterial agents. Biochar itself is chemically stable, acid and alkali resistant, and biodegradable, and can serve as a skeleton support for the material to maintain the long-term integrity of the particle structure; its porous structure can adsorb and fix pollutants, reduce the risk of secondary release, and help improve long-term remediation stability. The activated biochar of this invention can improve the removal efficiency of heavy metals, phosphorus and organic matter through physical adsorption; it can also provide colonization sites and microenvironments for microorganisms, promote microbial metabolic activity and enhance bioremediation efficiency; at the same time, it can promote full contact between pollutants and adsorption sites and microorganisms through pore mass transfer, and enhance the chemical-biological synergistic effect.

[0049] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0050] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The embodiments described below are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1: A method for preparing a targeted treatment material for pollutants in river and lake sediments is as follows:

[0052] S1: Add 25g of sodium-based attapulgite to 330mL of deionized water and ultrasonically disperse for 60min. Then let it stand for 60min to settle and discard the lower layer impurities. Centrifuge the upper layer suspension at 6000r / min for 10min. Then take the lower layer precipitate and dry it at 80℃ for 16h. Grind and pass it through 200 mesh to obtain purified attapulgite.

[0053] S2: Add 13 mL of 3-mercaptopropyltriethoxysilane to a mixed solvent of 275 mL anhydrous ethanol and 25 mL deionized water, and adjust the pH to 4.3 with 0.1 mol / L hydrochloric acid aqueous solution. After stirring for 30 min, add 20 g of purified attapulgite and sonicate for 60 min. Then stir for 6 h at 50 °C under a nitrogen atmosphere, centrifuge and wash the precipitate 3 times with anhydrous ethanol. Finally, disperse in 200 mL anhydrous ethanol to obtain a mercaptolated attapulgite dispersion.

[0054] S3: Under a nitrogen atmosphere, 6g of vinylphosphonic acid and 0.09g of 2,2-dimethoxy-2-phenylacetophenone were added to 200mL of mercapto-modified attapulgite dispersion and stirred for 20min. Then, the mixture was reacted under 100W, 365nm UV irradiation for 4h. After centrifugation, the precipitate was washed three times with anhydrous ethanol and dried under vacuum at 60℃ for 12h. Then, it was dispersed in 250mL of deionized water, and 13.5g of ferric chloride hexahydrate was added and stirred for 30min. Then, under a nitrogen atmosphere, the pH was adjusted to 4.3 with 0.5mol / L sodium hydroxide aqueous solution and stirred for 90min. Then, 2.25-2.65g of lanthanum nitrate hexahydrate was added and stirred for 20min. After adjusting the pH to 7.3, the mixture was stirred for 2h. Finally, the mixture was centrifuged, the precipitate was washed five times with deionized water, dried under vacuum at 60℃ for 12h, ground, and passed through a 200-mesh sieve to obtain functionalized modified attapulgite.

[0055] S4: Add 500 mL of deionized water to 200 g of target river and lake sediment and shake for 2 h. Then centrifuge and take the supernatant. Filter the supernatant through a 0.22 μm filter membrane to remove bacteria and obtain sediment leachate.

[0056] S5: Add 1L of sterile LB medium (containing 10g peptone, 5g yeast extract, 10g sodium chloride, pH 7.2) to 500g of target river and lake sediment and enrich it at 150 r / min for 72h at 25℃. Then, use a gradient ratio method to add sediment leachate for three generations of acclimatization, each generation cultured for 48h (LB medium to sediment leachate volume ratio of 2:1 for the first generation; 1:1 for the second generation; 1:2 for the third generation). Then centrifuge at 8000 r / min for 10min, collect the cells and resuspend them in 100mL of sterile physiological saline, then add 1g of trehalose and adjust OD. 600 After step 1.2, a bacterial suspension (viable bacteria count ≥10⁻⁶) was obtained. 9 (CFU / mL)

[0057] S6: Heat 18g of paraffin to 60℃ to melt and add 3mL of Span-80. Stir at 58℃ for 20min, then add 12g of nano calcium peroxide and stir at 800r / min for 10min to obtain a wax phase dispersion.

[0058] S7: Add 3 mL of Tween-80 to 600 mL of anhydrous ethanol and stir for 10 min. Then cool to 0 °C in an ice bath. While stirring at 500 r / min, add 33 g of wax phase dispersion using a preheated syringe (needle diameter 0.5 mm) and stir for 10 min in an ice bath. Then filter the microspheres with nylon filter cloth to collect the microspheres. Wash twice with anhydrous ethanol at 0 °C. Finally, spread the microspheres on a petri dish and air dry in a dark and ventilated place at 25 °C for 2 h to obtain the core microspheres.

[0059] S8: Add 9g of chitosan to 300mL of deionized water and stir for 20min. Then add 6mL of glacial acetic acid and stir for 10min. Adjust the pH to 5.0 with 0.5mol / L sodium hydroxide aqueous solution to obtain chitosan solution.

[0060] S9: Add 6g of sodium alginate to 300mL of deionized water and stir for 20min. After cooling to 3℃, add 27g of core microspheres and 120mL of bacterial suspension and stir at 200r / min for 8min. Then, dropwise add to 600mL of 2% (w / w) calcium chloride aqueous solution at 3℃. After cross-linking and curing at 3℃ for 2h, filter and wash 3 times with 3℃ deionized water. Then, immerse in 300mL of chitosan solution at 3℃ and stir at 100r / min for 10min. Filter again, remove the microspheres and wash 3 times with 3℃ deionized water. Finally, dry at 3℃ in the dark until the water content is 40% to obtain double-layer encapsulated microcapsules.

[0061] S10: Wash 50g of rice husk biochar with water until the pH of the filtrate is 6.6 and dry it at 105℃. Then, soak it in 200mL of 1mol / L hydrochloric acid aqueous solution for 12h to activate it. Wash it with water again until the pH of the filtrate is 6.6. Finally, dry it and pass it through a 200-mesh sieve to obtain activated biochar.

[0062] S11: Dry mix 45g of activated biochar with 2g of sodium alginate and 25g of functionalized modified attapulgite for 10min to obtain premixed dry powder;

[0063] S12: Add 3g sodium alginate and 2g sodium carboxymethyl cellulose to 180mL of deionized water at 40℃ and stir for 20min. After cooling to 25℃, add 72g of premixed dry powder and stir for 30min. Then let it stand at 4℃ for 30min. Add 40g of double-layer embedded microcapsules and gently stir for 2min. Then, use a large-diameter syringe or peristaltic pump to drip into 200mL of 3.5% calcium chloride aqueous solution and crosslink and solidify at 25℃ for 4h. Then, take out the particles and rinse them with deionized water 3 times. Finally, pre-freeze them at -20℃ for 5h and then dry them in a freeze dryer (cold trap temperature ≤ -50℃) for 12h to obtain a targeted treatment material for pollutants in river and lake sediment with a particle size of 3-4mm and a water content of 20%.

[0064] Example 2: A method for preparing a targeted treatment material for pollutants in river and lake sediments is as follows:

[0065] S1: Add 25g of sodium-based attapulgite to 345mL of deionized water and ultrasonically disperse for 70min. Then let it stand for 70min and discard the lower layer impurities. Centrifuge the upper suspension at 6000r / min for 15min. Then take the lower precipitate and dry it at 80℃ for 18h. Grind and pass it through 200 mesh to obtain purified attapulgite.

[0066] S2: Add 14 mL of 3-mercaptopropyltriethoxysilane to a mixed solvent of 275 mL anhydrous ethanol and 25 mL deionized water, and adjust the pH to 4.4 with 0.1 mol / L hydrochloric acid aqueous solution. After stirring for 40 min, add 22 g of purified attapulgite and sonicate for 70 min. Then stir at 50 °C under a nitrogen atmosphere for 6.5 h, centrifuge and wash the precipitate 4 times with anhydrous ethanol. Finally, disperse in 200 mL anhydrous ethanol to obtain a mercapto-modified attapulgite dispersion.

[0067] S3: Under a nitrogen atmosphere, 6.5 g of vinylphosphonic acid and 0.1 g of 2,2-dimethoxy-2-phenylacetophenone were added to 200 mL of mercapto-modified attapulgite dispersion and stirred for 25 min. Then, the mixture was reacted under 100 W, 365 nm UV irradiation for 4.5 h. After centrifugation, the precipitate was washed four times with anhydrous ethanol and dried under vacuum at 60 °C for 14 h. Then, it was dispersed in 275 mL of deionized water, and 14.8 g of ferric chloride hexahydrate was added and stirred for 40 min. Then, under a nitrogen atmosphere, the pH was adjusted to 4.5 with 0.5 mol / L sodium hydroxide aqueous solution and stirred for 95 min. Then, 2.45 g of lanthanum nitrate hexahydrate was added and stirred for 25 min. After adjusting the pH to 7.5, the mixture was stirred for 2 h. Finally, the mixture was centrifuged and the precipitate was washed six times with deionized water. The precipitate was dried under vacuum at 60 °C for 13 h, ground, and passed through a 200 mesh sieve to obtain functionalized modified attapulgite.

[0068] S4: Add 530 mL of deionized water to 200 g of target river and lake sediment and shake for 2 h. Then centrifuge and take the supernatant. Filter the supernatant through a 0.22 μm filter membrane to remove bacteria and obtain sediment leachate.

[0069] S5: Add 1L of sterile LB medium (containing 10g peptone, 5g yeast extract, 10g sodium chloride, pH 7.2) to 500g of target river and lake sediment and enrich it at 150 r / min for 72h at 25℃. Then, use a gradient ratio method to add sediment leachate for three generations of acclimatization, each generation for 48h (LB medium to sediment leachate volume ratio of 2:1 for the first generation; 1:1 for the second generation; and 1:2 for the third generation). Centrifuge at 8000 r / min for 11min, collect the cells, resuspend them in 110mL of sterile physiological saline, add 1.1g of trehalose, and adjust OD. 600 After step 1.2, a bacterial suspension (viable bacteria count ≥10⁻⁶) was obtained. 9 (CFU / mL)

[0070] S6: Heat 19g of paraffin to 60℃ to melt and add 3.2mL of Span-80. Stir at 59℃ for 25min, then add 13g of nano calcium peroxide and stir at 800r / min for 15min to obtain a wax phase dispersion.

[0071] S7: Add 3.2 mL of Tween-80 to 600 mL of anhydrous ethanol and stir for 15 min. Then cool to 2 °C in an ice bath. While stirring at 600 r / min, add 35 g of wax phase dispersion using a preheated syringe (needle diameter 0.8 mm) and stir in an ice bath for 13 min. Then filter and collect the microspheres using a sintered glass funnel. Wash three times with anhydrous ethanol at 2 °C. Finally, spread the microspheres on a petri dish and air-dry them in a dark and ventilated place at 28 °C for 3 h to obtain the core microspheres.

[0072] S8: Add 9.5g of chitosan to 325mL of deionized water and stir for 25min. Then add 6.5mL of glacial acetic acid and stir for 15min. Adjust the pH to 5.3 with 0.5mol / L sodium hydroxide aqueous solution to obtain chitosan solution.

[0073] S9: Add 6.5g sodium alginate to 335mL of deionized water and stir for 25min. After cooling to 4℃, add 28.5g core microspheres and 120mL bacterial suspension and stir at 200r / min for 9min. Then, dropwise add to 650mL of 2% (w / w) calcium chloride aqueous solution at 4℃. After cross-linking and curing at 4℃ for 2h, filter and wash 4 times with 4℃ deionized water. Then, immerse in 330mL of chitosan solution at 4℃ and stir at 100r / min for 13min. Filter again, remove the microspheres and wash 4 times with 4℃ deionized water. Finally, dry at 4℃ in the dark until the water content is 50% to obtain double-layer embedded microcapsules.

[0074] S10: Wash 55g of rice husk biochar with water until the pH of the filtrate is 6.9 and dry it at 105℃. Then, soak it in 210mL of 1mol / L hydrochloric acid aqueous solution for 13h to activate it. Wash it with water again until the pH of the filtrate is 6.9. Finally, dry it and pass it through a 200-mesh sieve to obtain activated biochar.

[0075] S11: Dry mix 50g of activated biochar with 2.3g of sodium alginate and 27.5g of functionalized modified attapulgite for 13min to obtain a premixed dry powder;

[0076] S12: Add 3.3g sodium alginate and 2.3g sodium carboxymethyl cellulose to 200mL of deionized water at 40℃ and stir for 25min. After cooling to 30℃, add 79.8g of premixed dry powder and stir for 35min. Then let stand at 4℃ for 40min. Add 45g of double-layer embedded microcapsules and gently stir for 3min. Then add dropwise to 230mL of 3.5% calcium chloride aqueous solution using a large-diameter syringe or peristaltic pump and crosslink and solidify at 30℃ for 4.5h. Then take out the particles and rinse them with deionized water 4 times. Finally, prefreeze at -20℃ for 5.5h and then dry in a freeze dryer (cold trap temperature ≤ -50℃) for 14h to obtain a targeted treatment material for pollutants in river and lake sediment with a particle size of 3-4mm and a water content of 18%.

[0077] Example 3: A method for preparing a targeted treatment material for pollutants in river and lake sediments is as follows:

[0078] S1: Add 25g of sodium-based attapulgite to 350mL of deionized water and ultrasonically disperse for 80min. Then let it stand for 80min and discard the lower layer of impurities. Centrifuge the upper layer of suspension at 6000r / min for 20min. Then take the lower layer of precipitate and dry it at 80℃ for 20h. Grind and pass it through 200 mesh to obtain purified attapulgite.

[0079] S2: Add 15 mL of 3-mercaptopropyltriethoxysilane to a mixed solvent of 275 mL anhydrous ethanol and 25 mL deionized water, and adjust the pH to 4.5 with 0.1 mol / L hydrochloric acid aqueous solution. After stirring for 50 min, add 24 g of purified attapulgite and sonicate for 80 min. Then stir at 50 °C under a nitrogen atmosphere for 7 h, centrifuge and wash the precipitate 5 times with anhydrous ethanol. Finally, disperse in 200 mL anhydrous ethanol to obtain a mercaptolated attapulgite dispersion.

[0080] S3: Under a nitrogen atmosphere, 7g of vinylphosphonic acid and 0.11g of 2,2-dimethoxy-2-phenylacetophenone were added to 200mL of mercapto-modified attapulgite dispersion and stirred for 30min. Then, the mixture was reacted under 100W, 365nm UV light for 5h. After centrifugation, the precipitate was washed 5 times with anhydrous ethanol and dried under vacuum at 60℃ for 16h. Then, it was dispersed in 300mL of deionized water, and 16.1g of ferric chloride hexahydrate was added and stirred for 50min. Then, under a nitrogen atmosphere, the pH was adjusted to 4.7 with 0.5mol / L sodium hydroxide aqueous solution and stirred for 100min. Then, 2.65g of lanthanum nitrate hexahydrate was added and stirred for 30min. After adjusting the pH to 7.7, the mixture was stirred for 2h. Finally, the mixture was centrifuged and the precipitate was washed 7 times with deionized water. The precipitate was dried under vacuum at 60℃ for 14h, ground, and passed through a 200-mesh sieve to obtain functionalized modified attapulgite.

[0081] S4: Add 550 mL of deionized water to 200 g of target river and lake sediment and shake for 2 h. Then centrifuge and take the supernatant. Filter the supernatant through a 0.22 μm filter membrane to remove bacteria and obtain sediment leachate.

[0082] S5: Add 1L of sterile LB medium (containing 10g peptone, 5g yeast extract, 10g sodium chloride, pH 7.2) to 500g of target river and lake sediment and enrich it at 150 r / min for 72h at 25℃. Then, use a gradient ratio method to add sediment leachate for three generations of acclimatization, each generation for 48h (LB medium to sediment leachate volume ratio of 2:1 for the first generation; 1:1 for the second generation; and 1:2 for the third generation). Then, centrifuge at 8000 r / min for 12min, collect the cells, resuspend them in 120mL of sterile physiological saline, add 1.2g of trehalose, and adjust the OD. 600 After step 1.2, a bacterial suspension (viable bacteria count ≥10⁻⁶) was obtained. 9 (CFU / mL)

[0083] S6: Heat 20g of paraffin to 60℃ to melt and add 3.4mL of Span-80. Stir at 60℃ for 30min, then add 14g of nano calcium peroxide and stir at 800r / min for 20min to obtain a wax phase dispersion.

[0084] S7: Add 3.4 mL of Tween-80 to 600 mL of anhydrous ethanol and stir for 20 min. Then cool to 4 °C in an ice bath. Add 37 g of wax phase dispersion with a preheated syringe (needle diameter 0.8 mm) while stirring at 800 r / min and stirring in an ice bath for 15 min. Then filter the microspheres with nylon filter cloth to collect the microspheres. Wash the microspheres three times with anhydrous ethanol at 4 °C. Finally, spread the microspheres on a petri dish and air-dry them in a dark and ventilated place at 30 °C for 4 h to obtain the core microspheres.

[0085] S8: Add 10g of chitosan to 350mL of deionized water and stir for 30min. Then add 7mL of glacial acetic acid and stir for 20min. Adjust the pH to 5.5 with 0.5mol / L sodium hydroxide aqueous solution to obtain chitosan solution.

[0086] S9: Add 7g sodium alginate to 350mL of deionized water and stir for 30min. After cooling to 5℃, add 30g core microspheres and 120mL bacterial suspension and stir at 200r / min for 10min. Then, dropwise add to 700mL of 2% calcium chloride aqueous solution at 5℃. After cross-linking and curing at 5℃ for 2h, filter and wash 5 times with 5℃ deionized water. Then, immerse in 350mL chitosan solution at 5℃ and stir at 100r / min for 15min. Filter again, remove the microspheres and wash 5 times with 5℃ deionized water. Finally, dry at 5℃ in the dark until the water content is 60% to obtain double-layer encapsulated microcapsules.

[0087] S10: Wash 60g of rice husk biochar with water until the pH of the filtrate is 7.2 and dry it at 105℃. Then, soak it in 220mL of 1mol / L hydrochloric acid aqueous solution for 14h to activate it. Wash it with water again until the pH of the filtrate is 7.2. Finally, dry it and pass it through a 200-mesh sieve to obtain activated biochar.

[0088] S11: Dry mix 55g of activated biochar with 2.5g of sodium alginate and 30g of functionalized modified attapulgite for 15min to obtain a premixed dry powder;

[0089] S12: Add 3.5g sodium alginate and 2.5g sodium carboxymethyl cellulose to 220mL of deionized water at 40℃ and stir for 30min. After cooling to 35℃, add 87.5g of premixed dry powder and stir for 40min. Then let it stand at 4℃ for 50min. Add 50g of double-layer embedded microcapsules and gently stir for 3min. Then, use a large-diameter syringe or peristaltic pump to drip into 250mL of 3.5% calcium chloride aqueous solution and crosslink and solidify at 35℃ for 5h. Then, take out the particles and rinse them 5 times with deionized water. Finally, pre-freeze them at -20℃ for 6h and then dry them in a freeze dryer (cold trap temperature ≤ -50℃) for 16h to obtain a targeted treatment material for pollutants in river and lake sediment with a particle size of 3-4mm and a water content of 15%.

[0090] Comparative Example 1:

[0091] Compared with Example 1, this comparative example only replaces the "200mL thiolized attapulgite dispersion" added in the preparation process of S3 with "200mL anhydrous ethanol and 20g purified attapulgite mixed dispersion". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a targeted treatment material for pollutants in river and lake sediments is obtained.

[0092] Comparative Example 2:

[0093] Compared with Example 1, this comparative example only replaces the "functionalized modified attapulgite" added in the preparation process of S11 with "purified attapulgite". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a targeted treatment material for pollutants in river and lake sediments is obtained.

[0094] Comparative Example 3:

[0095] Compared with Example 1, this comparative example only did not add "2,2-dimethoxy-2-phenylacetophenone" in the preparation process of S3. All other steps and parameters were the same, and will not be repeated here. The final result is a targeted treatment material for pollutants in river and lake sediments.

[0096] Comparative Example 4:

[0097] Compared with Example 1, this comparative example only replaces the "core microspheres" added in the preparation process of S9 with "nano-calcium peroxide". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a targeted treatment material for pollutants in river and lake sediments is obtained.

[0098] Comparative Example 5:

[0099] Compared with Example 1, this comparative example only did not add "double-layer encapsulated microcapsules" in the preparation process of S12. All other steps and parameters were the same, and will not be repeated here. Finally, a targeted treatment material for pollutants in river and lake sediments was obtained.

[0100] Comparative Example 6:

[0101] Compared with Example 1, this comparative example only replaces the "activated biochar" added in the preparation process of S11 with the same mass of "rice husk biochar". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a targeted treatment material for pollutants in river and lake sediments is obtained.

[0102] Performance testing:

[0103] Measurement of target precision:

[0104] Referring to the static adsorption test method (refer to HJ 700-2014 and GB / T 5750.6-2023), weigh 0.2 g of functionalized modified attapulgite (comparative example 2 is purified attapulgite) and add it to 100 mL of Pb-containing... 2+ Cd 2+ (Concentrations of 5 mg / L each) and PO4 3- In a mixed simulated solution (concentration of 10 mg / L), the solution was kept at 25 °C and oscillated at 150 r / min for 24 h. The concentrations of heavy metal ions and phosphate ions in the solution before and after adsorption were measured, and the Pb / Cd selective adsorption coefficient was calculated. The results are shown in Table 1.

[0105] Another 10g of double-layer-encapsulated microcapsules were placed in simulated sediment leachate (the simulated sediment leachate was prepared by adding 0.6g sodium chloride, 0.15g calcium chloride dihydrate, 0.1g magnesium chloride hexahydrate, 0.25g sodium bicarbonate, 0.03g dipotassium hydrogen phosphate, and 0.02g potassium dihydrogen phosphate to 800mL of deionized water and stirring to dissolve. Then, deionized water was added to bring the volume to 1000mL. The pH was then adjusted to 7.1-7.3 with 0.1mol / L hydrochloric acid or 0.1mol / L sodium hydroxide aqueous solution. The mixture was then autoclaved at 121℃ for 20 min and finally sterilized by vacuum filtration through a 0.22μm aqueous filter membrane. After cooling to room temperature, the mixture was sealed for later use). The mixture was cultured at 25℃ with shaking at 100r / min for 72h. Samples were taken periodically to determine the number of viable bacteria released into the aqueous phase, and the colonization rate (%) of the bacteria in the target medium was calculated. The results are shown in Table 1.

[0106] Determination of effective utilization rate:

[0107] 10g of double-layer-encapsulated microcapsules were weighed and placed in 200mL of deionized water (25℃). Samples were taken on days 1, 3, 7, 14 and 28 to determine the concentration of hydrogen peroxide in the release solution (converted to the cumulative release of reactive oxygen species). The cumulative sustained release rate (%) of nano-calcium peroxide was then calculated. The results are shown in Table 1.

[0108] Determination of long-term stability:

[0109] The double-layered embedded microcapsules were sealed and stored in a constant temperature and humidity chamber (25℃, relative humidity 60%) for 90 days in the dark. Samples were taken on day 0 and day 90, dissolved, coated and counted the number of viable bacteria, and the activity decay rate (%) after 90 days was calculated. The results are shown in Table 1.

[0110] Measurement of collaborative governance capabilities:

[0111] 200g of target river and lake sediment was weighed and placed in a 2L reactor. 1000mL of deionized water and 20g of the targeted treatment material for river and lake sediment pollutants prepared in each example or comparative example were added. The mixture was irrigated at 120r / min at 25℃ for 7 days. After the irrigation was completed, the supernatant and sediment leachate were taken and the leaching concentrations of heavy metals (Pb, Cd, Cu), total nitrogen and total phosphorus, and organic pollutants (calculated as permanganate index CODMn) were measured. The simultaneous removal rate (%) of each pollutant was calculated. The results are shown in Table 2.

[0112] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-6

[0113]

[0114] Table 2: Performance test results of Examples 1-3 and Comparative Examples 1-6

[0115]

[0116] Data Analysis:

[0117] As can be seen from Tables 1 and 2, the targeted treatment material for pollutants in river and lake sediments prepared in the embodiments of the present invention has excellent targeting accuracy, effective utilization rate, long-term stability, and synergistic treatment capability for complex pollution of heavy metals, nitrogen and phosphorus, and organic matter.

[0118] In Comparative Example 1 of this invention, the mercapto-modified attapulgite dispersion was replaced with a purified attapulgite dispersion, omitting the mercapto-silanization modification step. The selective adsorption coefficient for Pb / Cd, and the removal rates of heavy metals and total phosphorus significantly decreased, while the cell colony rate, oxygen release rate, and activity decay rate remained largely unchanged. This may be because, without the mercapto-silanization layer, vinylphosphonic acid cannot achieve covalent grafting via a thiol-ene click reaction, and can only be loaded onto the attapulgite surface through physical adsorption. The low loading and weak binding force of phosphonic acid groups significantly reduces the chelation selectivity for lead ions. Simultaneously, the iron-lanthanum hydroxide lacks anchoring sites for phosphonic acid groups, resulting in poor loading uniformity and anti-dissolution ability, weakening the specific adsorption and fixation effect of phosphorus, ultimately leading to a simultaneous decrease in the treatment efficiency of heavy metals and phosphorus.

[0119] Comparative Example 2 replaced the functionalized modified attapulgite with purified attapulgite, completely omitting the thiol grafting, phosphonic acid modification, and iron-lanthanum loading processes. The selective adsorption coefficient decreased to 1.3, and the removal rates of various pollutants remained at a low level. This may be because purified attapulgite relies solely on surface ion exchange and physical adsorption, lacking specific chelating groups such as thiol and phosphonic acid. It has no targeted enrichment ability for heavy metals such as lead and cadmium, nor does it have iron-lanthanum active sites for specific phosphorus fixation, resulting in the worst targeting precision. Simultaneously, the lack of functional groups means there is no linkage between chemical adsorption and biodegradation, preventing effective optimization of the microbial environment and simultaneously deteriorating the removal efficiency of total nitrogen and organic matter.

[0120] In Comparative Example 3, without the addition of the photoinitiator 2,2-dimethoxy-2-phenylacetophenone, the thiol-ene click reaction could not be effectively initiated, and the selective adsorption coefficient dropped to 1.7. The removal rates of heavy metals and phosphorus were both lower than in Example 1. This may be because, without the photoinitiator, the click reaction between thiols and vinyl groups lacks active initiation centers, significantly reducing the covalent grafting rate of vinyl phosphonic acid. Only a small number of phosphonic acid groups adhere to the material surface through non-covalent interactions, resulting in insufficient specific sites for heavy metal chelation and phosphorus coordination, thus weakening the targeted adsorption capacity. Simultaneously, the number of anchoring sites for iron-lanthanum hydroxide decreased accordingly, leading to reduced load stability. Therefore, the long-term passivation effect and the ability to treat complex pollution were inferior to the fully modified system.

[0121] In Comparative Example 4, replacing the core microspheres with directly mixed nano-calcium peroxide, and lacking the paraffin hydrophobic controlled-release structure, resulted in a sharp drop in bacterial colony rate to 19.7%, an increase in bacterial activity attenuation rate to 75.2%, and a significant decrease in total nitrogen and organic matter removal rates. This may be because, without the controlled-release barrier of the paraffin layer, nano-calcium peroxide rapidly decomposes upon contact with water, causing a burst release of oxygen. Although the short-term cumulative release is high, the oxygen source is quickly depleted, making it impossible to maintain a long-term aerobic microenvironment at the sediment interface, and the actual effective utilization rate of oxygen is greatly reduced. At the same time, the strong oxidizing environment released by the rapid decomposition of calcium peroxide directly damages the embedded functional bacteria, causing a sharp drop in bacterial survival rate and sediment colony rate, and significantly weakening the microorganisms' ability to degrade nitrogen and organic matter. In addition, a sudden increase in local oxygen concentration easily causes disturbance at the sediment interface, which is not conducive to the stable passivation of heavy metals and phosphorus, ultimately leading to a significant deterioration in the synergistic treatment effect of complex pollution.

[0122] Comparative Example 5, without the addition of the double-layer encapsulated microcapsule component, only retained the chemical adsorption carrier, resulting in a significant decrease in the removal rates of total nitrogen and organic matter. This may be because, without the double-layer encapsulated microcapsules, the material lacks a slow-release oxygen source and functional microbial units, making it unable to construct a local aerobic microenvironment to drive microbial degradation. Relying solely on the physicochemical adsorption of functionalized attapulgite and biochar is insufficient to achieve efficient removal of total nitrogen and organic pollutants. Furthermore, the lack of synergistic effects between microbial metabolism and chemical adsorption leads to insufficient long-term effectiveness of heavy metal passivation and phosphorus fixation, significantly limiting the overall synergistic treatment capacity for complex pollution and hindering the integrated management of multiple pollutants.

[0123] Comparative Example 6: Replacing activated biochar with unactivated rice husk biochar resulted in varying degrees of decrease in the removal rates of total nitrogen, total phosphorus, and organic matter. This may be because unactivated rice husk biochar has underdeveloped pores and a low specific surface area, resulting in a weak ability to enrich pollutants in the aquatic environment. It cannot effectively increase the local pollutant concentration to assist targeted adsorption, nor can it provide sufficient colonization pores and microenvironments for functional bacteria, leading to decreased bacterial colonization stability and metabolic activity. At the same time, the poor dispersibility of unactivated biochar easily exacerbates the agglomeration of functionalized attapulgite powder, obscuring some active adsorption sites, resulting in a decrease in the effective utilization rate of adsorbed components. Ultimately, the synergistic effect of chemical adsorption and bioremediation is weakened, and the combined pollution treatment effect is not as good as that of the activated system.

[0124] In summary, the synergistic effect of covalent targeted modification of functionalized attapulgite, controlled-release encapsulation structure of bilayer microcapsules, and carrier enhancement of activated biochar ensures the comprehensive performance of the material in terms of targeting accuracy, effective utilization rate, long-term stability, and synergistic treatment capability of complex pollution. The absence of any structure or component will cause the deterioration of the corresponding performance dimension.

[0125] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing a targeted treatment material for pollutants in river and lake sediments, characterized in that, Includes the following steps: S1: Dry mix activated biochar with sodium alginate and functionalized modified attapulgite for 10-15 minutes to obtain premixed dry powder; S2: Add sodium alginate and sodium carboxymethyl cellulose to deionized water at 35-40℃ and stir for 20-30 minutes. After cooling to 25-35℃, add premixed dry powder and stir for 30-40 minutes. Then let it stand at 4℃ for 30-50 minutes. Add double-layer embedded microcapsules, stir, and drop into calcium chloride aqueous solution and crosslink and solidify for 4-5 hours. Then take out the particles, wash, freeze dry, and obtain a targeted treatment material for pollutants in river and lake sediment. The activated biochar is rice husk biochar that has been activated by soaking in hydrochloric acid. The functionalized modified attapulgite is prepared by first washing and purifying sodium-based attapulgite with deionized water, then reacting it with 3-mercaptopropyltriethoxysilane, then reacting it with vinylphosphonic acid under ultraviolet light, and finally reacting it with ferric chloride hexahydrate, sodium hydroxide, and lanthanum nitrate hexahydrate to support lanthanum iron-iron composite hydroxide. The double-layer encapsulated microcapsules are prepared by first encapsulating nano-calcium peroxide in paraffin, and then encapsulating it with a bacterial suspension of river and lake sediment acclimatization bacteria in a sodium alginate-chitosan double layer and cross-linking and solidifying it.

2. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 1, characterized in that, The mass ratio of activated biochar, sodium alginate, and functionalized modified attapulgite in S1 is 45-55: 2-2.5: 25-30; The ratio of deionized water, sodium alginate, sodium carboxymethyl cellulose, premixed dry powder, double-layer encapsulated microcapsules, and calcium chloride aqueous solution in S2 is 180-220mL: 3-3.5g: 2-2.5g: 72-87.5g: 40-50g: 200-250mL; The mass fraction of the calcium chloride aqueous solution in S2 is 3.5%.

3. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 1, characterized in that, The method for preparing the activated biochar is as follows: Rice husk biochar was washed with water until the pH of the filtrate was 6.6-7.2 and then dried. After that, it was soaked in hydrochloric acid aqueous solution for 12-14 hours to activate it. Then it was washed with water, dried, and sieved to obtain activated biochar.

4. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 3, characterized in that, The ratio of rice husk biochar to hydrochloric acid aqueous solution is 50-60g: 200-220mL; The concentration of the hydrochloric acid aqueous solution is 1 mol / L.

5. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 1, characterized in that, The preparation method of the functionalized modified attapulgite is as follows: A1: Add sodium-based attapulgite to deionized water and ultrasonically disperse for 60-80 minutes. Then let it stand for 60-80 minutes and discard the lower layer of impurities. Then centrifuge, and then take the lower layer of precipitate for drying, grinding and sieving to obtain purified attapulgite. A2: Add 3-mercaptopropyltriethoxysilane to a mixed solvent of anhydrous ethanol 1 and deionized water and adjust the pH to 4.3-4.

5. Stir for 30-50 min, then add purified attapulgite and ultrasonically disperse for 60-80 min. Then stir at 50℃ under a nitrogen atmosphere for 6-7 h, then centrifuge, wash the precipitate, and finally disperse it in anhydrous ethanol 2 to obtain a mercaptolated attapulgite dispersion. A3: Under a nitrogen atmosphere, vinylphosphonic acid and 2,2-dimethoxy-2-phenylacetophenone were added to the mercapto-modified attapulgite dispersion and stirred for 20-30 min. Then, the mixture was reacted under 100W, 365nm UV irradiation for 4-5 h. After centrifugation, the precipitate was washed, dried, and then dispersed in deionized water. Ferric chloride hexahydrate was added and stirred for 30-50 min. The pH was then adjusted to 4.3-4.7 under a nitrogen atmosphere and stirred for 90-100 min. Lanthanum nitrate hexahydrate was added and stirred for 20-30 min. The pH was adjusted to 7.3-7.7 and stirred for 2 h. Finally, the mixture was centrifuged, washed, dried, ground, and sieved to obtain the functionalized modified attapulgite.

6. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 5, characterized in that, The mass ratio of deionized water to sodium-based attapulgite in A1 is 330-350:25; The ratio of anhydrous ethanol 1, deionized water, 3-mercaptopropyltriethoxysilane, purified attapulgite, and anhydrous ethanol 2 in A2 is 275mL:25mL:13-15mL:20-24g:200mL. The ratio of the amount of mercaptolated attapulgite dispersion, vinylphosphonic acid, 2,2-dimethoxy-2-phenylacetophenone, deionized water, ferric chloride hexahydrate, and lanthanum nitrate hexahydrate in A3 is 200mL: 6-7g: 0.09-0.11g: 250-300mL: 13.5-16.1g: 2.25-2.65g.

7. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 1, characterized in that, The preparation method of the double-layer encapsulated microcapsules is as follows: B1: Add deionized water to the target river and lake bottom sediment and shake for 2 hours. Then centrifuge and take the supernatant. After filtration, obtain the bottom sediment leachate. B2: Sterile LB medium was added to the target river and lake sediment and enriched at 25°C for 72 hours. Then, sediment leachate was added for three generations of acclimatization treatment. The bacterial cells were then collected by centrifugation and resuspended in sterile physiological saline. Trehalose was then added to adjust the OD. 600 After reaching 1.2, a bacterial suspension was obtained; B3: After melting paraffin at 60℃, add Span-80, stir at 58-60℃ for 20-30 min, add nano calcium peroxide and stir for 10-20 min to obtain a wax phase dispersion; B4: Add Tween-80 to anhydrous ethanol and stir for 10-20 min. Then cool to 0-4℃ and add the wax phase dispersion while stirring. Stir for 10-15 min, then filter, wash, and air dry in the dark for 2-4 h to obtain core microspheres. B5: Add chitosan to deionized water and stir for 20-30 minutes, then add glacial acetic acid and stir for 10-20 minutes, then adjust the pH to 5.0-5.5 to obtain a chitosan solution; B6: Add sodium alginate to deionized water and stir for 20-30 minutes. After cooling to 3-5℃, add the core microspheres and bacterial suspension and stir for 8-10 minutes. Then drop it into a calcium chloride aqueous solution at 3-5℃. After cross-linking and curing at 3-5℃ for 2 hours, filter and wash. Then immerse it in a chitosan solution at 3-5℃ and stir for 10-15 minutes. Filter, wash and dry until the water content is 40%-60% to obtain double-layer embedded microcapsules.

8. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 7, characterized in that, The ratio of deionized water added to the target river and lake sediments described in B1 is 200g: 500-550mL; The ratio of the target river and lake sediment, sterile LB medium, sterile physiological saline, and trehalose described in B2 is 500g:1000mL:100-120mL:1-1.2g; In the three-generation acclimatization treatment described in B2, the volume ratio of LB medium to sediment leachate for the first generation was 2:1, the volume ratio of LB medium to sediment leachate for the second generation was 1:1, and the volume ratio of LB medium to sediment leachate for the third generation was 1:2, with each generation cultured for 48 hours. The ratio of paraffin, Span-80, and nano-calcium peroxide described in B3 is 18-20g: 3-3.4mL: 12-14g.

9. The method for preparing the targeted treatment material for pollutants in river and lake sediments according to claim 7, characterized in that, The volume ratio of anhydrous ethanol, Tween-80, and wax phase dispersion described in B4 is 600 mL: 3-3.4 mL: 33-37 g; The ratio of deionized water, chitosan, and glacial acetic acid used in B5 is 300-350mL: 9-10g: 6-7mL; The ratio of deionized water, sodium alginate, kernel microspheres, bacterial suspension, calcium chloride aqueous solution, and chitosan solution in B6 is 300-350mL: 6-7g: 27-30g: 120mL: 600-700mL: 300-350mL; The mass fraction of the calcium chloride aqueous solution described in B6 is 2%.

10. A targeted treatment material for pollutants in river and lake sediments, characterized in that, It is prepared by the method described in any one of claims 1-9.

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