Composite functional material with POPs (Persistent Organic Pollutants) targeted repair capability as well as preparation method and application of composite functional material

Abstract

The invention belongs to the technical field of environmental functional materials, and particularly relates to a composite functional material with POPs targeted repair capacity and a preparation method and application thereof. The composite functional material comprises sodium percarbonate, a molecularly imprinted polymer recognition catalyst layer and a porous shell layer which are sequentially arranged from inside to outside, the molecularly imprinted polymer recognition catalyst layer comprises a porous medium, a catalytic active center and a molecularly imprinted polymer; the catalytic active center and the molecularly imprinted polymer are loaded in the porous medium; the molecularly imprinted polymer is a polymer with a specific recognition cavity, which is formed by a polymerization reaction by taking a target pollutant molecule as a template. The composite functional material can actively capture and enrich target hydrophobic pollutants from soil pore water or an adsorption phase, efficient and selective activation of an oxidizing agent and rapid degradation of the pollutants are achieved on a material-pollutant interface, and therefore the remediation efficiency, selectivity and long-term effectiveness are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials technology, specifically relating to a composite functional material with targeted repair capabilities for POPs, its preparation method, and its application. Background Technology

[0002] Persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in soil and groundwater are extremely difficult to remediate due to their strong hydrophobicity, high toxicity, and strong adsorption by soil organic matter. In-situ chemical oxidation technology using sodium percarbonate (SPC) as an oxidant is one of the mainstream methods, but it faces three inherent bottlenecks: First, non-selective rapid decomposition: SPC decomposes rapidly upon contact with water in aquifers, generating highly reactive free radicals with extremely short lifetimes. Most of these free radicals are ineffectively quenched by a large amount of non-target reducing substances in the soil, resulting in low oxidant utilization and a limited radius of action. Second, severe mass transfer limitations: Target pollutants are strongly adsorbed or encapsulated in soil micropores and organic matter, and traditional homogeneous catalysts or free radicals have difficulty contacting and degrading these "locked-in" pollutants. Third, lack of targeting and long-term effectiveness: Existing SPC slow-release materials can only physically delay dissolution and cannot preferentially identify and enrich specific toxic pollutants from complex soil matrices, nor can they achieve "on-demand supply" of oxidants.

[0003] Molecularly imprinted polymers (MIPs), as synthetic polymer materials with predetermined selectivity, provide specific recognition sites by creating recognition cavities in the polymer network that are precisely complementary to specific target molecules (called "template molecules") in terms of shape, size, and chemical functional groups. However, traditional bulk MIPs have slow mass transfer, and their single adsorption function cannot achieve the complete degradation of pollutants.

[0004] Therefore, it is of great significance to develop a composite functional material based on MIPs that has the ability to target and repair POPs. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a composite functional material integrating "porous media pre-enrichment - molecularly imprinted targeted recognition - sodium percarbonate slow release - interface confined catalysis," along with its preparation method and applications. This material can actively capture and enrich target hydrophobic pollutants from soil pore water or the adsorbed phase, achieving efficient and selective activation of oxidants and rapid degradation of pollutants at the material-pollutant interface, thereby significantly improving remediation efficiency, selectivity, and long-term effectiveness.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following solution:

[0007] The first aspect of the present invention provides a composite functional material with targeted repair capability for POPs, the composite functional material comprising, from the inside out, sodium percarbonate, a molecularly imprinted polymer recognition catalytic layer and a porous outer shell layer;

[0008] The molecularly imprinted polymer recognition catalytic layer comprises a porous medium, a catalytic active center, and a molecularly imprinted polymer; the catalytic active center and the molecularly imprinted polymer are supported in the porous medium.

[0009] The molecularly imprinted polymer is a polymer with specific recognition cavities formed by polymerization reaction using target pollutant molecules as templates.

[0010] The porous medium is porous biochar or porous zeolite.

[0011] In some embodiments of the present invention, the porous medium is amination-modified hydrophobic porous biochar or amination-modified hydrophobic porous zeolite.

[0012] The catalytic active center includes any one or a combination of several of nano-zero-valent iron, metal phthalocyanine, and metal oxide.

[0013] In some embodiments of the present invention, the catalytic active center is nano-zero-valent iron or metal phthalocyanine.

[0014] In some embodiments of the present invention, the catalytic active center is nano-zero valent iron or cobalt phthalocyanine.

[0015] The target pollutant molecules are polycyclic aromatic hydrocarbons and / or polychlorinated biphenyls.

[0016] In some embodiments of the present invention, the target pollutant molecule includes any one or a combination of several of phenanthrene, PCB-77, pyrene, DDT, benzo[a]pyrene, PCB-153, acenaphthene, hexachlorobenzene, fluoranthene, chlordane, and dibenzo[a,h]anthene.

[0017] In some embodiments of the present invention, the target pollutant molecule is phenanthrene and / or PCB-77.

[0018] The sodium percarbonate has a particle size of 0.5~1.5 mm.

[0019] In some embodiments of the present invention, the sodium percarbonate has a particle size of 0.8 to 1 mm.

[0020] A second aspect of the present invention provides a method for preparing a composite functional material, comprising the following steps:

[0021] S1. The porous medium is modified by amination, and the catalytic active center is loaded into the porous medium to obtain a functionalized support;

[0022] S2. The target pollutant molecules, functional monomers and functionalized carriers are pre-assembled in a solvent, and then a crosslinking agent and an initiator are added to form a polymerization product on the surface of sodium percarbonate through a polymerization reaction;

[0023] S3. The target pollutant molecules in the polymerization product are eluted with an eluent to obtain the molecularly imprinted polymer recognition catalyst layer coated on the surface of sodium percarbonate;

[0024] S4. Construct a porous outer shell layer outside the molecularly imprinted polymer recognition catalytic layer to obtain the composite functional material.

[0025] In S1, the catalytic active center is loaded into a porous medium by impregnation reduction or coordination anchoring.

[0026] In some embodiments of the present invention, nano-zero valent iron is loaded into a porous medium by the impregnation reduction method, including the following steps: immersing the amination-modified porous medium in FeCl3 solution, stirring and adsorbing, and then reducing it with freshly prepared NaBH4 solution to prepare an amination-modified porous medium loaded with the catalytically active center nZVI.

[0027] In some embodiments of the present invention, cobalt phthalocyanine is loaded into a porous medium by the coordination anchoring method, including the following steps: refluxing the amination-modified porous medium and CoPc in dimethyl sulfoxide to anchor CoPc on the surface and in the pores of the porous medium, thereby preparing an amination-modified porous medium loaded with the catalytically active center CoPc.

[0028] In S2, the mass ratio of the target pollutant molecule, functional monomer, and functionalized carrier is 1:(3~6):(5~15); the polymerization reaction is SI-ATRP polymerization or photo-initiated seed swelling polymerization.

[0029] In some embodiments of the present invention, the SI-ATRP polymerization reaction includes the following steps: dissolving the target pollutant molecule (template) and 4-vinylpyridine (functional monomer) in a mixed solvent composed of acetonitrile / toluene, adding a functionalized support, and ultrasonically dispersing for 30 minutes for pre-assembly. Subsequently, ethylene glycol dimethacrylate (EGDMA, crosslinking agent) and a cuprous bromide / bipyridine catalytic system (initiator) are added, and SI-ATRP polymerization is carried out at 60 °C under nitrogen protection for 8 hours to obtain the polymerization product.

[0030] In some embodiments of the present invention, the photoinitiated seed swelling polymerization reaction is carried out as follows: SPC is used as the seed and dispersed in an aqueous solution of polyvinyl alcohol (PVA) and ultrasonically dispersed for 10 minutes. A functionalized carrier is added and stirred for 30 minutes to allow it to adsorb onto the seed surface. Separately, the target pollutant molecule (template), dodecafluoroheptyl methacrylate (functional monomer), and photoinitiator Irgacure 2959 (initiator) are dissolved in toluene, ultrasonically dissolved, and then slowly added dropwise to the above seed dispersion. Stirring is continued for 2 hours to allow the monomer to fully swell. The reaction system is transferred to a photoreactor and photoinitiated seed swelling polymerization is carried out at 30 °C under nitrogen protection and irradiated with 365 nm UV light for 8 hours. After the reaction is completed, the mixture is filtered, washed three times with ethanol, and vacuum dried at 60 °C to obtain the polymerization product.

[0031] In some embodiments of the present invention, in S3, the eluent is a methanol / acetic acid mixture with a volume ratio of 9:1 or a hexane / acetone mixture with a volume ratio of 1:1.

[0032] In S4, the porous outer shell layer is mesoporous silica or porous carbon shell; the porous outer shell layer is constructed by sol-gel method or hydrothermal carbonization method.

[0033] In some embodiments of the present invention, mesoporous silica is constructed via the sol-gel method, comprising the following steps: dispersing the product obtained in S3 in a mixture of hexadecyltrimethylammonium bromide (CTAB), water, and ethanol; slowly adding a mixture of tetraethyl orthosilicate (TEOS) and HDTMS with stirring, and reacting at 40 °C for 24 hours; collecting by centrifugation, and calcining at 550 °C to remove CTAB, at which point the hydrophobic groups of HDTMS are retained, ultimately yielding a composite functional material coated with mesoporous silica having hydrophobic channels.

[0034] In some embodiments of the present invention, the porous carbon shell is constructed by the hydrothermal carbonization method, comprising the following steps: dispersing the product obtained in S3 in a mixture containing resorcinol, formaldehyde solution (37%), and water; adjusting the pH to 8.5 with Na2CO3; and reacting at 40 °C for 24 hours. After centrifugation, washing, and drying at 80 °C, the product is carbonized at 800 °C for 2 hours under a nitrogen atmosphere. Finally, it is activated with 0.5 M KOH solution for 1 hour to obtain a porous carbon shell with a pore size of approximately 15 nm. This shell is then post-treated with HDTMS to create hydrophobic channels, ultimately yielding a composite functional material coated with a porous carbon shell containing hydrophobic channels.

[0035] A third aspect of the present invention provides the application of a composite functional material in the remediation of POPs-contaminated soil and / or groundwater.

[0036] In some embodiments of the present invention, a composite functional material capable of degrading phenanthrene was successfully prepared by the above preparation method. When added to simulated contaminated soil, the degradation rate after 7 days demonstrated that the composite functional material has a good degradation effect on phenanthrene in the soil, with a degradation rate of 88%. At the same time, characterization of hydroxyl radicals in the simulated contaminated soil showed that the material could still provide continuous generation of hydroxyl radicals on day 5, demonstrating the application prospects of the composite functional material in remediating POPs contaminated soil.

[0037] In some embodiments of the present invention, composite functional materials capable of degrading PCB-77 were successfully prepared by the above preparation method. By comparing the materials with the control group material without the addition of molecularly imprinted polymers through sand column experiments, it was shown that the porous zeolite-based composite functional materials can effectively intercept and degrade PCB-77 in the mobile phase, demonstrating the application prospects of composite functional materials in the remediation of POPs-contaminated groundwater.

[0038] The mechanism of this invention involves introducing porous media materials (such as biochar and zeolite) as key components into a molecularly imprinted polymerization system. These porous media not only serve as carriers, but their abundant functional groups and pore structures themselves exhibit strong adsorption properties for hydrophobic organic pollutants. Through copolymerization, these adsorption sites are "woven" into the imprinted polymer network, working synergistically with the artificially imprinted cavities to form a dual capture mechanism of "broad-spectrum adsorption (porous media) + precise identification (imprinted cavity)," greatly enhancing the enrichment capacity for low-concentration, highly adsorbent target pollutants in complex soil and groundwater matrices.

[0039] Beneficial effects:

[0040] 1. Excellent targeted enrichment and anti-interference capabilities: The synergistic effect of porous media and imprinted cavities enables the material to possess both high adsorption capacity and high selectivity. Even in the presence of high concentrations of natural organic matter (such as humic acid), it can effectively capture target pollutants, overcoming the problem of decreased selectivity of traditional MIPs in complex environments.

[0041] 2. Highly efficient interface-confined catalysis: Catalytic active centers are pre-loaded onto porous media and positioned near the imprinted cavity. After pollutants are captured, they can be catalytically degraded in situ at the adsorption site without long-distance diffusion, achieving the goal of recognition and degradation. This greatly improves the local concentration and utilization efficiency of free radicals, and the degradation efficiency can be several times higher than that of non-imprinted catalysts.

[0042] 3. Intelligent and Long-Lasting Controlled Release: The porous outer shell precisely regulates reaction kinetics. On the one hand, it slowly releases SPC, extending its action time from several hours to several days; on the other hand, it promotes the entry of target pollutants into the material interior preferentially over moisture, realizing the on-demand consumption of oxidants and avoiding ineffective decomposition. Attached Figure Description

[0043] The present invention will be further described in detail below with reference to the accompanying drawings, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0044] Figure 1 This is a signal diagram of ·OH during the degradation of phenanthrene in the porous biochar-based composite material in Example 1 of the present invention. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0046] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0047] This invention provides a composite functional material with targeted repair capabilities for pollutants (POPs). The composite functional material comprises a three-layer composite structure consisting of a core, an intermediate layer, and an outer layer. The core of the composite functional material is sodium percarbonate (SPC), which functions as an oxidant to provide the reactive oxygen species required for pollutant degradation. To balance the injection flowability of the composite functional material (avoiding clogging) with sufficient reactive oxygen species loading, the particle size of the SPC is controlled between 0.5 and 1.5 mm.

[0048] The middle layer of the composite functional material is a molecularly imprinted polymer (SPC) recognition catalytic layer, which functions to achieve precise identification, enrichment, and catalytic degradation of pollutants. The SPC recognition catalytic layer comprises a porous medium, a catalytic active center, and a molecularly imprinted polymer. The porous medium, serving as the carrier of the SPC, provides a large specific surface area and a stable three-dimensional structure. Simultaneously, the porous structure itself exhibits a strong physical adsorption capacity for organic pollutants. This invention uses porous biochar or modified zeolite as the porous medium. The catalytic active center is a catalyst used to activate SPC and generate strong oxidizing free radicals (such as ·OH). This application uses nano-zero-valent iron (nZVI), metal phthalocyanines (such as cobalt phthalocyanine CoPc, iron phthalocyanine FePc), or metal oxides (such as Co3O4) as the catalytic active center. The molecularly imprinted polymer is a polymer with a specific recognition cavity formed through polymerization using the target pollutant molecule as a template. The molecularly imprinted polymer provides precise recognition capabilities; its cavity is highly complementary to the target molecule in size, shape, and chemical functional groups, enabling it to specifically capture target pollutants from complex environments. The target pollutant molecules in this invention include any one or a combination of several of the following: phenanthrene, PCB-77, pyrene, DDT, benzo[a]pyrene (BaP), PCB-153, acenaphthene, hexachlorobenzene (HCB), fluoranthene, chlordane, and dibenzo[a,h]anthracene (DBahA).

[0049] The outer layer of the composite functional material is a porous shell layer with dual functions: first, it acts as a physical barrier, regulating the rate of water molecule infiltration and hydrogen peroxide diffusion to achieve the slow release of SPC; second, its nanoscale pores can serve as pre-enrichment channels, preferentially adsorbing and transporting hydrophobic target pollutants into the inner layer recognition sites. This invention uses mesoporous silica or resin-derived porous carbon shells as the porous outer shell layer.

[0050] The following section provides a further explanation of the composite functional material scheme provided by this invention through the preparation and performance characterization of porous biochar-based composite functional materials degrading phenanthrene and modified zeolite-based composite functional materials degrading PCB-77.

[0051] Example 1: Porous biochar-based composite functional material for degrading phenanthrene

[0052] This embodiment provides a method for preparing porous biochar-based composite functional materials for degrading phenanthrene, including the following steps:

[0053] S1. Modification of porous biochar support and loading of catalytic active centers: 100-mesh bamboo biochar (specific surface area 580 m²) was used as the support. 2The biochar was washed sequentially with 1 M HCl and 5% H2O2 to remove ash and increase oxygen-containing functional groups. After drying, it was dispersed in anhydrous toluene containing 3-aminopropyltriethoxysilane (APTES) and refluxed for 6 hours for amination modification to obtain modified biochar. Subsequently, the modified biochar was immersed in a 0.1 M FeCl3 ethanol solution, stirred for adsorption, and then reduced with freshly prepared 0.1 M NaBH4 solution to prepare amination-modified biochar (nZVI@N-BC) with catalytically active center nZVI.

[0054] S2. Surface Imprinted Polymerization: 0.178 g of phenanthrene (template) and 0.65 g of 4-vinylpyridine (4-VP, functional monomer) were dissolved in 50 mL of a mixed solvent consisting of acetonitrile / toluene at a volume ratio of 4:1. 1.5 g of nZVI@N-BC prepared in step S1 was added, and the mixture was ultrasonically dispersed for 30 minutes for pre-assembly. Subsequently, 20 mmol of ethylene glycol dimethacrylate (EGDMA, crosslinking agent) and 2% (by mass) of cuprous bromide / bipyridine catalytic system (where the mass ratio of cuprous bromide to bipyridine was 1:3) were added. SI-ATRP polymerization was carried out at 60 °C under N2 protection for 8 hours to obtain the polymer product.

[0055] S3. Template elution: The polymerization product was Soxhlet extracted with a methanol / acetic acid mixture at a volume ratio of 9:1 until no phenanthrene was detected, thus obtaining the molecularly imprinted polymer recognition catalyst layer. Then, the molecularly imprinted polymer recognition catalyst layer was mixed with 0.8 mm sodium percarbonate particles at a mass ratio of 1:2 under slight pressure, so that the molecularly imprinted polymer recognition catalyst layer was physically adsorbed onto the surface of the core SPC.

[0056] S4. Construction of a porous outer shell: The product obtained in S3 was dispersed in a solution containing 0.5 g cetyltrimethylammonium bromide (CTAB), 50 mL of water, and 20 mL of ethanol. A mixture of 2 mL tetraethyl orthosilicate (TEOS) and 0.5 mL HDTMS was slowly added dropwise with stirring, and the reaction was carried out at 40 °C for 24 hours. The mixture was collected by centrifugation and calcined at 550 °C to remove CTAB. During this process, the hydrophobic groups of HDTMS were retained, ultimately yielding a porous biochar-based composite functional material coated with mesoporous silica and possessing hydrophobic channels.

[0057] Performance testing:

[0058] 1. In simulated contaminated soil (initial concentration of phenanthrene 100 mg / kg, containing 2% humic acid), 1% (w / w) of the porous biochar-based composite functional material prepared in this embodiment was added.

[0059] Table 1 shows the degradation rate of phenanthrene in simulated contaminated soil over 7 days. After the addition of porous biochar-based composite functional material, the degradation rate reached 30% on day 1, exceeded 80% on day 5, reaching 81.5%, and peaked at 88% on day 7. This experiment demonstrates the excellent degradation effect and slow-release performance of the porous biochar-based composite functional material provided in this embodiment.

[0060] Table 1. Degradation rate of phenanthrene in simulated contaminated soil within 7 days.

[0061]

[0062] 2. The hydroxyl radicals (·OH) in the simulated contaminated soil were characterized using an electron paramagnetic resonance spectrometer. The specific method is as follows:

[0063] Spin trapping agent preparation: 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was selected as the spin trapping agent for ·OH. A 0.1 mol / L DMPO aqueous solution was prepared and used immediately.

[0064] Soil sample preparation: Take 5.0 g of simulated contaminated soil containing 1% (w / w) composite functional material, add 10 mL of DMPO solution, stir well, and immediately transfer to a quartz EPR sample tube.

[0065] EPR testing conditions: A Bruker EMXplus X-band electron paramagnetic resonance spectrometer was used. The test parameters were set as follows: central magnetic field 3470 G, scan width 100 G, microwave frequency 9.85 GHz, modulation amplitude 1.0 G, modulation frequency 100 kHz, scan time 30 s, and the test was conducted at room temperature.

[0066] Signal acquisition and processing: Samples were taken and tested on the 1st and 5th days after material addition, and the characteristic quartet of the DMPO-·OH adduct was recorded. The relative amount of ·OH generated was qualitatively compared by the changes in peak intensity.

[0067] Figure 1 This is a signal diagram of ·OH during the degradation of phenanthrene in porous biochar-based composite materials, from... Figure 1 It can be seen that the characteristic signal of ·OH was successfully detected in simulated contaminated soil after the addition of the composite functional material. Furthermore, the peak shape of the characteristic quartet remained unchanged on days 1 and 5, indicating that ·OH was still present in the soil on day 5. The intensity ratio of the characteristic quartet on days 1 and 5 was 1:2:2:1, g≈2.005, indicating that the ability of the composite functional material to generate ·OH in the soil is time-dependent.

[0068] 3. Selective Degradation Experiment and Selectivity Coefficient Characterization: To quantitatively evaluate the selective degradation ability of the composite functional material for the target pollutant phenanthrene in a complex matrix, a dual-solute competitive degradation experiment was conducted, and the selectivity coefficient relative to humic acid (HA) was calculated. The specific experimental steps are as follows:

[0069] Prepare a mixed aqueous solution containing equal mass concentrations (10 mg / L) of phenanthrene and humic acid (HA, as a model disturbance representing complex organic matter in soil) (background electrolyte: 0.01 M CaCl2, pH≈7.0). Add 0.1 g of the porous biochar-based composite functional material prepared in this example to 200 mL of the above mixed solution. Place the reaction system in a 25 ℃ constant temperature shaker (150 rpm) and react in the dark for 6 hours. Take samples at preset time points and immediately filter through a 0.22 μm filter membrane to terminate the reaction.

[0070] Experimental characterization and calculation: The residual concentration of phenanthrene in the filtrate was determined by high performance liquid chromatography (HPLC), and its degradation rate (Dt) was calculated. Phe The change in dissolved organic carbon (DOC) concentration in the filtrate was determined using a total organic carbon (TOC) analyzer. The degradation rate of HA (Ddegradation) was estimated by measuring the decrease in DOC before and after the reaction, combined with the known carbon content of HA. HA This method can effectively distinguish the degradation contributions of target pollutants from non-target complex organic matter. By fitting the degradation kinetic data of phenanthrene and HA, the apparent first-order degradation rate constants (k-values) of the material for both are obtained. Phe and k HA The selectivity coefficient (α) is defined as the ratio of the degradation rate constant of the material for the target substance to that for the non-target substance, i.e., α = k Phe / k HA .

[0071] Experiments showed that, in this competitive system, the degradation rate constant k of the material for phenanthrene was... Phe It is 0.87 h -1 The degradation rate of humic acid is often k HA 0.15 h -1 Therefore, the selectivity coefficient α = 0.87 / 0.15 ≈ 5.8. This result quantitatively demonstrates that the composite functional material of the present invention can preferentially identify and degrade the target pollutant phenanthrene, maintaining excellent selectivity even in the presence of a large amount of structurally similar complex organic matter, overcoming the bottleneck of the large-scale ineffective consumption of oxidants in traditional non-selective oxidation processes.

[0072] Example 2: Porous zeolite-based composite functional material for degrading PCB-77

[0073] This embodiment provides a method for preparing a porous zeolite-based composite functional material for degrading PCB-77, comprising the following steps:

[0074] S1. Modification of porous zeolite and loading of catalytic active centers: Nano-sized ZSM-5 zeolite was added to a 1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:10 g / mL, and converted to NH4 through an ion exchange reaction. + Type I zeolite was then calcined to obtain Type H zeolite to increase its acidity. The obtained Type H zeolite was then refluxed with cobalt phthalocyanine (CoPc) at a mass ratio of 80:1 in dimethyl sulfoxide to anchor CoPc on the zeolite surface and within the pores, thus obtaining CoPc-ZSM-5.

[0075] S2. Surface Imprinted Polymerization: 2 g of SPC (1 mm particle size) was used as seeds and dispersed in 100 mL of 2% (w / w) polyvinyl alcohol (PVA) aqueous solution, and ultrasonically dispersed for 10 minutes. 2 g of CoPc-ZSM-5 (hydrophilic part) was added and stirred for 30 minutes to allow it to adsorb onto the seed surface. Separately, 0.2 g of PCB-77 (template), 1 g of dodecafluoroheptyl methacrylate (DFMA, hydrophobic part), and 0.05 g of photoinitiator Irgacure 2959 were dissolved in 20 mL of toluene, ultrasonically dissolved, and then slowly added dropwise to the above seed dispersion. Stirring was continued for 2 hours to allow the monomers to fully swell.

[0076] The reaction system was transferred to a photoreactor and subjected to photoinitiated seed swelling polymerization under nitrogen protection at 30 °C for 8 hours with 365 nm UV light. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried under vacuum at 60 °C to obtain the polymerization product.

[0077] S3. Template elution: The polymerization product obtained in S2 is extracted with a 1:1 volume ratio of hexane / acetone mixture using Soxhlet extraction until PCB-77 is undetectable, thus obtaining the molecularly imprinted polymer recognition catalyst layer adsorbed on the surface of the core SPC.

[0078] S4. Construction of a porous outer shell: A porous carbon shell was constructed using phenolic resin as a precursor. The product obtained in S3 was dispersed in a mixture containing 5.0 g resorcinol, 20 mL formaldehyde solution (37%), and 100 mL water. The pH was adjusted to 8.5 with Na2CO3, and the reaction was carried out at 40 °C for 24 hours. After centrifugation, washing, and drying at 80 °C, the product was carbonized at 800 °C for 2 hours under a N2 atmosphere. Finally, it was activated with 0.5 M KOH solution for 1 hour to obtain a porous carbon shell with a pore size of approximately 15 nm. After hydrophobic post-treatment using HDTMS, a porous zeolite-based composite functional material with hydrophobic channels was finally obtained.

[0079] Performance verification:

[0080] The targeted interception and degradation performance of the porous zeolite-based composite functional material was verified by sand column experiments. A control group material without molecularly imprinted polymers was prepared according to the preparation method of this embodiment. Specifically, PCB-77, which served as a template in step S2, was removed, while other preparation methods remained unchanged, resulting in the control group material.

[0081] The specific steps of the sand column experiment are as follows:

[0082] Sand column device construction: Use an plexiglass column (2.5 cm inner diameter, 30 cm height), with a quartz sand support layer (about 2 cm) at the bottom, and fill the upper layer with a 20 cm mixture of quartz sand (40~60 mesh) containing 1% (w / w) composite functional material and a quartz sand mixture containing 1% (w / w) control group material, and then cover the top with 2 cm of clean quartz sand.

[0083] Preparation of contaminated solution: Using background electrolyte solution (0.01 mol / L CaCl2, pH≈7.0) as the mobile phase, simulated contaminated groundwater with an initial concentration of 1.0 mg / L of PCB-77 was prepared.

[0084] Experimental procedure: A constant flow pump was used to control the flow rate at 1.0 mL / min (equivalent to a hydraulic residence time of about 4 hours). The contaminated liquid was injected from the top of the column, and the effluent was continuously collected from the bottom of the column.

[0085] Sample collection and analysis: Effluent samples were collected every 24 hours for a total of 7 days. After extraction with hexane, the concentration of PCB-77 was determined by gas chromatography-mass spectrometry (GC-MS), and the removal rate was calculated.

[0086] Table 2 shows the comparison of PCB-77 concentration in the effluent of the porous zeolite-based composite functional material and the control group material in a 7-day sand column experiment. As can be seen from Table 2, compared with the control group material without added molecularly imprinted polymer, the porous zeolite-based composite functional material provided in this embodiment has a significantly improved adsorption and degradation capacity for PCB-77. The experiment proves that the porous zeolite-based composite functional material can effectively intercept and degrade PCB-77 in the mobile phase, and has good prospects for application in groundwater.

[0087] Table 2. Concentration of PCB-77 in the effluent of porous zeolite-based composite functional materials and control materials in sand column experiments.

[0088]

[0089] This invention provides a composite functional material with targeted repair capabilities for POPs, its preparation method, and its application. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A composite functional material with targeted repair capabilities for POPs, characterized in that, The composite functional material comprises, from the inside out, sodium percarbonate, a molecularly imprinted polymer recognition catalytic layer, and a porous outer shell layer; The molecularly imprinted polymer recognition catalytic layer comprises a porous medium, a catalytic active center, and a molecularly imprinted polymer; the catalytic active center and the molecularly imprinted polymer are supported in the porous medium. The molecularly imprinted polymer is a polymer with specific recognition cavities formed by polymerization reaction using target pollutant molecules as templates.

2. The composite functional material according to claim 1, characterized in that, The porous medium is porous biochar or porous zeolite.

3. The composite functional material according to claim 1 or 2, characterized in that, The catalytic active center includes any one or a combination of several of nano-zero-valent iron, metal phthalocyanine, and metal oxide.

4. The composite functional material according to claim 3, characterized in that, The target pollutant molecules are polycyclic aromatic hydrocarbons and / or polychlorinated biphenyls.

5. The composite functional material according to claim 4, characterized in that, The target pollutant molecules include any one or a combination of several of phenanthrene, PCB-77, pyrene, DDT, benzo[a]pyrene, PCB-153, acenaphthene, hexachlorobenzene, fluoranthene, chlordane, and dibenzo[a,h]anthene.

6. A method for preparing the composite functional material according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. The porous medium is modified by amination, and the catalytic active center is loaded into the porous medium to obtain a functionalized support; S2. The target pollutant molecules, functional monomers and functionalized carriers are pre-assembled in a solvent, and then a crosslinking agent and an initiator are added to form a polymerization product on the surface of sodium percarbonate through a polymerization reaction; S3. The target pollutant molecules in the polymerization product are eluted with an eluent to obtain the molecularly imprinted polymer recognition catalyst layer coated on the surface of sodium percarbonate; S4. Construct a porous outer shell layer outside the molecularly imprinted polymer recognition catalytic layer to obtain the composite functional material.

7. The preparation method according to claim 6, characterized in that, In S1, the catalytic active center is loaded into a porous medium by impregnation reduction or coordination anchoring.

8. The preparation method according to claim 6, characterized in that, In S2, the mass ratio of the target pollutant molecule, functional monomer, and functionalized carrier is 1:(3~6):(5~15); the polymerization reaction is SI-ATRP polymerization or photo-initiated seed swelling polymerization.

9. The preparation method according to claim 6, characterized in that, In S4, the porous outer shell layer is mesoporous silica or porous carbon shell; the porous outer shell layer is constructed by sol-gel method or hydrothermal carbonization method.

10. The application of the composite functional material according to any one of claims 1 to 5 in the remediation of POPs-contaminated soil and / or POPs-contaminated groundwater.

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