Underground water pollution repairing agent and preparation method thereof
By integrating materials such as kaolin, biochar, MOFs, and layered double hydroxides, a four-in-one groundwater pollution remediation agent is formed, which solves the problems of poor material interface contact and insufficient stability in existing technologies, and achieves efficient and long-lasting groundwater pollution remediation effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN HUADI ENVIRONMENTAL TECH CO LTD
- Filing Date
- 2026-04-03
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, composite materials used in groundwater pollution remediation suffer from poor interfacial contact, high electron transfer resistance, and an inability to form efficient adsorption and catalytic synergy. Furthermore, the materials lack sufficient resistance to interference and long-term stability in complex matrices.
By integrating materials such as kaolin, biochar, MOFs, and layered double hydroxides through chemical bonding, in-situ growth, or interface engineering, a super remediation system integrating adsorption, catalysis, reduction, and ion exchange is formed. The properties of materials such as poly(o-phenylenediamine) modified biochar and persulfate-activated modified kaolin are utilized to improve the stability and remediation efficiency of the materials in groundwater.
It achieves efficient removal of oxygen-containing anions such as arsenate and chromate in groundwater, reduction and fixation of highly toxic heavy metals, and mineralization of recalcitrant organic matter, significantly improving the degradation efficiency of pollutants and the long-term effectiveness of materials, while avoiding the loss of nanocatalysts and secondary pollution.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of groundwater remediation technology, and more specifically, to a groundwater pollution remediation agent and its preparation method. Background Technology
[0002] Groundwater pollution not only directly threatens human drinking water safety but also has profound impacts on the ecological environment and socio-economic development. Ecologically, groundwater pollution leads to the destruction of aquatic habitats, and heavy metal pollution can even affect terrestrial ecosystems through bioaccumulation in the food chain. Socioeconomically, groundwater pollution may force the closure of local drinking water sources, thereby increasing the cost of water supply and even impacting regional economic development. Long-term groundwater pollution also poses potential threats to human health, including causing cancer, neurological damage, and endocrine disorders. Groundwater remediation has a significant time lag; once pollution occurs, the remediation process is complex and lengthy. Therefore, minimizing the impact of pollution and implementing effective remediation measures are key issues in current groundwater protection efforts.
[0003] In existing technologies, composite materials are simply physically mixed, resulting in poor interfacial contact between components, high resistance to electron transfer, and an inability to achieve efficient adsorption and catalytic synergy. Furthermore, existing materials lack sufficient resistance to interference and long-term stability in complex matrices. Summary of the Invention
[0004] This invention provides a groundwater pollution remediation agent and its preparation method. Through chemical bonding, in-situ growth, or interface engineering, the advantages of each component material are integrated to form a super remediation system encompassing adsorption, catalysis, reduction, and ion exchange. Using kaolin and biochar as a rigid framework avoids the problems of easy aggregation and loss of nanomaterials, making it suitable for long-term in-situ remediation.
[0005] In a first aspect, the present invention provides a groundwater pollution remediation agent comprising the following raw materials in the following weight ratio: 45-65% poly(o-phenylenediamine) modified biochar, 10-20% persulfate activated modified kaolin, 5-19% MOFs, and 20-25% layered double hydroxides.
[0006] Preferably, the specific surface area of the groundwater pollution remediation agent is 400-600 m². 2 / g, the average pore size of the groundwater pollution remediation agent is 2~10nm.
[0007] Preferably, the poly(o-phenylenediamine) modified biochar is prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomers under acidic conditions, and the resulting poly(o-phenylenediamine) segments are directly grown on the surface of the pretreated biochar.
[0008] Preferably, the mass ratio of the o-phenylenediamine monomer, biochar, and ammonium persulfate is 1~2:2~3:1~1.5.
[0009] Preferably, the persulfate-activated modified kaolin is prepared by adding a metal salt solution to nano-kaolin, precipitating it under alkaline conditions, and allowing metal hydroxide crystals to nucleate and grow in situ on the kaolin surface; the amount of metal salt solution added is 5% to 20%.
[0010] Preferably, the metal salt solution is selected from at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, ferrous sulfate heptahydrate, cobalt nitrate hexahydrate, cobalt chloride hexahydrate, copper chloride dihydrate, and manganese acetate tetrahydrate.
[0011] Preferably, the D50 particle size of the persulfate-activated modified kaolin is 2~5μm.
[0012] Secondly, the present invention provides a method for preparing a groundwater pollution remediation agent, comprising the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, and sonicate for 45-65 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, dissolve 2-methylimidazole in ethanol to prepare solution B, add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 25~30℃ for 12~24h to obtain the precursor. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol 3 to 5 times, vacuum dry it at 80 to 100°C for 12 to 16 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
[0013] Preferably, in step (2), the molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 1~2:7~10.
[0014] In summary, the present invention has the following beneficial effects: 1. In this invention, layered double hydroxides efficiently remove oxygen-containing anions such as arsenate and chromate through interlayer anion exchange. Poly(o-phenylenediamine)-modified biochar utilizes the electron-rich properties of poly(o-phenylenediamine) to reduce highly toxic Cr(VI) and U(VI) to less toxic Cr(III) and U(IV) and then fix them. The unsaturated metal sites of MOFs can specifically coordinate and adsorb Pb. 2+ Cd 2 +Isocational compounds. Modified kaolin activates persulfate to generate strong oxidizing free radicals, mineralizing recalcitrant chlorinated hydrocarbons, antibiotics, and PFAS. Poly(o-phenylenediamine) modified biochar rapidly adsorbs organic molecules through π-π stacking and hydrogen bonding, enriching them near the catalytic site and improving degradation efficiency. The tunable pore size of MOFs acts as a molecular sieve, selectively capturing trace amounts of emerging pollutants of specific sizes.
[0015] 2. The ultra-high specific surface area of MOFs and the interlayer anion exchange capacity of layered double hydroxides in this invention can rapidly capture and enrich trace, dispersed pollutants (such as antibiotics and PFAS) from groundwater on the material surface and within the pores, much like a sponge. Simultaneously, the pollutants are enriched at the adjacent transition metal active sites (Fe / Co, etc.) supported on the modified kaolin. This short-range diffusion mechanism of adsorption-catalysis greatly shortens the attack distance of free radicals, avoids ineffective quenching of free radicals in the bulk solution, and significantly improves oxidation efficiency. Poly(o-phenylenediamine) coated on the insulating biochar and kaolin surfaces forms a continuous conductive network, promoting the rapid transfer of electrons from defect sites on the pollutants or biochar surface to persulfate molecules, significantly reducing the activation energy barrier and accelerating the generation rate of sulfate free radicals. Besides generating free radicals, poly(o-phenylenediamine) can also mediate direct electron transfer between pollutants and the catalyst. This pathway is less affected by background water quality (such as humic acid and chloride ions) and is more selective. Biochar provides micron-sized macropores as fluid channels, preventing the material from clogging the porous media when injected into the formation; MOFs and layered double hydroxides provide abundant mesopores and micropores, specifically designed to capture small molecule pollutants; the nanosheet structure of modified kaolin not only increases the specific surface area but also creates a labyrinth effect between layers, prolonging the residence time of pollutants and ensuring continuous reaction; it can maintain long-term permeability and reactivity even in actual groundwater containing a large number of suspended particles.
[0016] 3. The groundwater pollution remediation agent prepared in this invention integrates the advantages of four materials through chemical bonding, in-situ growth, or interface engineering, forming a super remediation system integrating adsorption, catalysis, reduction, and ion exchange. This solves the problem that single materials cannot cope with complex and compound pollution, overcomes the shortcomings of traditional adsorption methods such as easy saturation and secondary pollution, and significantly improves the stability and long-term effectiveness of the remediation agent in real groundwater environments. It also solves the problems of easy loss and secondary pollution of nanocatalysts. Through in-situ growth technology, MOFs, layered double hydroxides, and metal oxide nanoparticles are not simply physically mixed, but are firmly anchored to the surface of poly(o-phenylenediamine) modified biochar framework and persulfate-activated modified kaolin through chemical bonds. Kaolin, as a stable aluminosilicate mineral, provides a natural protective chamber for metal active centers in its interlayer domains, reducing the leaching of metal ions in acidic or complex water conditions. After the reaction, the concentration of metal ions in the water is usually below 0.05 mg / L, far below environmental standards, avoiding secondary pollution.
[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of the present invention. Detailed Implementation
[0018] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.
[0019] Example Example 1 A groundwater pollution remediation agent comprises the following raw materials in the following weight ratio: 45% poly(o-phenylenediamine) modified biochar, 15% persulfate activated modified kaolin, 15% MOFs, and 25% layered double hydroxides.
[0020] Poly(o-phenylenediamine) modified biochar was prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomer under acidic conditions, and the resulting poly(o-phenylenediamine) segments were directly grown on the surface of pretreated biochar; the mass ratio of o-phenylenediamine monomer, biochar and ammonium persulfate was 1:2:1.
[0021] Persulfate-activated modified kaolin was prepared by adding a metal salt solution to nano-kaolin and precipitating it under alkaline conditions (pH=8). The metal hydroxide crystals then nucleated and grew in situ on the kaolin surface. The amount of metal salt solution added was 5%. The metal salt solution was selected from a mixture of ferric chloride hexahydrate and ferric nitrate nonahydrate in a mass ratio of 1:2. The D50 particle size of the persulfate-activated modified kaolin was 2 μm.
[0022] A method for preparing a groundwater pollution remediation agent includes the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, sonicate for 45 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, and dissolve 2-methylimidazole in ethanol to prepare solution B. Add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 25°C for 12 hours to obtain the precursor. The molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 1:7. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol 5 times, dry it under vacuum at 80°C for 12 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
[0023] Example 2 A groundwater pollution remediation agent comprises the following raw materials in the following weight ratio: 55% poly(o-phenylenediamine) modified biochar, 10% persulfate activated modified kaolin, 15% MOFs, and 20% layered double hydroxides.
[0024] Poly(o-phenylenediamine) modified biochar was prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomer under acidic conditions, and the resulting poly(o-phenylenediamine) segments were directly grown on the surface of pretreated biochar; the mass ratio of o-phenylenediamine monomer, biochar and ammonium persulfate was 1:3:1.1.
[0025] Persulfate-activated modified kaolin was prepared by adding a metal salt solution to nano-kaolin and precipitating it under alkaline conditions (pH=8). The metal hydroxide crystals then nucleated and grew in situ on the kaolin surface. The amount of metal salt solution added was 8%. The metal salt solution was selected from a mixture of ferric chloride hexahydrate and ferric nitrate nonahydrate in a mass ratio of 1:2. The D50 particle size of the persulfate-activated modified kaolin was 3 μm.
[0026] A method for preparing a groundwater pollution remediation agent includes the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, sonicate for 50 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, and dissolve 2-methylimidazole in ethanol to prepare solution B. Add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 25°C for 12 hours to obtain the precursor. The molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 1:8. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol 5 times, vacuum dry it at 85°C for 14 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
[0027] Example 3 A groundwater pollution remediation agent comprises the following raw materials in the following weight ratio: 60% poly(o-phenylenediamine) modified biochar, 10% persulfate activated modified kaolin, 10% MOFs, and 20% layered double hydroxides.
[0028] Poly(o-phenylenediamine) modified biochar was prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomer under acidic conditions, and the resulting poly(o-phenylenediamine) segments were directly grown on the surface of pretreated biochar; the mass ratio of o-phenylenediamine monomer, biochar and ammonium persulfate was 2:3:1.4.
[0029] Persulfate-activated modified kaolin was prepared by adding a metal salt solution to nano-kaolin and precipitating it under alkaline conditions (pH=8). The metal hydroxide crystals then nucleated and grew in situ on the kaolin surface. The amount of metal salt solution added was 12%. The metal salt solution was selected from a mixture of ferric chloride hexahydrate and ferric nitrate nonahydrate in a mass ratio of 1:2. The D50 particle size of the persulfate-activated modified kaolin was 3 μm.
[0030] A method for preparing a groundwater pollution remediation agent includes the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, sonicate for 55 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, and dissolve 2-methylimidazole in ethanol to prepare solution B. Add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 30°C for 24 hours to obtain the precursor. The molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 2:7. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol 4 times, dry it under vacuum at 90°C for 15 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
[0031] Example 4 A groundwater pollution remediation agent comprises the following raw materials in the following weight ratio: 65% poly(o-phenylenediamine) modified biochar, 10% persulfate activated modified kaolin, 5% MOFs, and 20% layered double hydroxides.
[0032] Poly(o-phenylenediamine) modified biochar was prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomer under acidic conditions, and the resulting poly(o-phenylenediamine) segments were directly grown on the surface of pretreated biochar; the mass ratio of o-phenylenediamine monomer, biochar and ammonium persulfate was 2:3:1.5.
[0033] Persulfate-activated modified kaolin was prepared by adding a metal salt solution to nano-kaolin and precipitating it under alkaline conditions (pH=8). The metal hydroxide crystals then nucleated and grew in situ on the kaolin surface. The amount of metal salt solution added was 20%. The metal salt solution was selected from a mixture of ferric chloride hexahydrate and ferric nitrate nonahydrate in a mass ratio of 1:2. The D50 particle size of the persulfate-activated modified kaolin was 5 μm.
[0034] A method for preparing a groundwater pollution remediation agent includes the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, sonicate for 65 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, and dissolve 2-methylimidazole in ethanol to prepare solution B. Add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 30°C for 24 hours to obtain the precursor. The molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 2:9. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol three times, dry it under vacuum at 100°C for 16 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
[0035] Comparative Example 1 The difference from Example 1 is that no layered double hydroxide was added.
[0036] Comparative Example 2 The difference from Example 1 is that no persulfate was added to activate and modify the kaolin.
[0037] Comparative Example 3 The difference from Example 1 is that no poly(o-phenylenediamine) modified biochar was added.
[0038] Performance testing: 1. Removal rate of groundwater containing 10 mg / L tetracycline within 30 min; 2. The removal rate in groundwater containing 10 mg / L humic acid; 3. Efficiency retention after 6 cycles. The results are shown in Table 1.
[0039] Table 1
[0040] As can be seen from the results in Table 1, the composite material prepared in the embodiments of the present invention has a significant removal effect on tetracycline and humic acid in groundwater, with a removal rate of over 95% and a removal rate of over 88%.
[0041] The above description is merely an exemplary embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A groundwater pollution remediation agent, characterized in that, The raw materials include the following weight ratios: 45-65% poly(o-phenylenediamine) modified biochar, 10-20% persulfate activated modified kaolin, 5-19% MOFs, and 20-25% layered double hydroxides.
2. The groundwater pollution remediation agent according to claim 1, characterized in that, The specific surface area of the groundwater pollution remediation agent is 400~600 m². 2 / g, the average pore size of the groundwater pollution remediation agent is 2~10nm.
3. The groundwater pollution remediation agent according to claim 1, characterized in that, The poly(o-phenylenediamine) modified biochar was prepared by using ammonium persulfate to initiate the oxidative polymerization of o-phenylenediamine monomers under acidic conditions, and the resulting poly(o-phenylenediamine) segments were directly grown on the surface of the pretreated biochar.
4. The groundwater pollution remediation agent according to claim 4, characterized in that, The mass ratio of o-phenylenediamine monomer, biochar, and ammonium persulfate is 1~2:2~3:1~1.
5.
5. The groundwater pollution remediation agent according to claim 1, characterized in that, The persulfate-activated modified kaolin is prepared by adding a metal salt solution to nano-kaolin, precipitating it under alkaline conditions, and nucleating and growing metal hydroxide crystals in situ on the surface of the kaolin; the amount of metal salt solution added is 5% to 20%.
6. The groundwater pollution remediation agent according to claim 6, characterized in that, The metal salt solution is selected from at least one of ferric chloride hexahydrate, ferric nitrate nonahydrate, ferrous sulfate heptahydrate, cobalt nitrate hexahydrate, cobalt chloride hexahydrate, copper chloride dihydrate, and manganese acetate tetrahydrate.
7. The groundwater pollution remediation agent according to claim 1, characterized in that, The D50 particle size of the persulfate-activated modified kaolin is 2~5μm.
8. The method for preparing the groundwater pollution remediation agent according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Weigh out poly(o-phenylenediamine) modified biochar, persulfate-activated modified kaolin and layered double hydroxide and disperse them in DMF solvent, and sonicate for 45-65 min to form a uniform suspension; (2) Dissolve zinc nitrate hexahydrate in ethanol to prepare solution A, dissolve 2-methylimidazole in ethanol to prepare solution B, add the suspension obtained in step (1) to solution A and solution B and stir vigorously. Stir continuously at 25~30℃ for 12~24h to obtain the precursor. (3) After centrifuging and collecting the precursor obtained in step (2), wash it repeatedly with ethanol 3 to 5 times, vacuum dry it at 80 to 100°C for 12 to 16 hours, grind and sieve it to obtain the groundwater pollution remediation agent.
9. The method for preparing the groundwater pollution remediation agent according to claim 9, characterized in that, In step (2), the molar ratio of zinc nitrate hexahydrate in solution A to 2-methylimidazole in solution B is 1~2:7~10.