Adsorbing material based on organic and inorganic double-network crosslinking and preparation method thereof

Abstract

The invention discloses an adsorption material based on organic and inorganic double-network crosslinking and a preparation method thereof, and relates to the technical field of special chemical materials for environmental pollution treatment, the adsorption material comprises an adsorption aggregate and a network structure, the network structure is arranged to coat the adsorption aggregate, and the adsorption aggregate can be communicated with the external environment; the adsorption aggregate has a pore structure, and the network structure comprises a basic cross-linked network, an inorganic cross-linked network and an organic cross-linked network. Through an organic-inorganic double-network cross-linked structure, on the premise that a traditional cement binder is not used, zero-interference packaging on the original adsorption performance is achieved, and the purpose that in the prior art, a traditional binder can damage the microcosmic pore structure and the surface activity of the material is avoided is achieved.

Description

Technical Field

[0001] This invention relates to the field of special reagents and materials for environmental pollution treatment, specifically to an adsorption material based on organic and inorganic dual-network crosslinking and its preparation method. Background Technology

[0002] Urban non-point source pollution (especially initial rainwater runoff) has become one of the main sources of water pollution. This type of pollution not only leads to the deterioration of river water quality but can also have a significant impact on downstream wastewater treatment systems. To alleviate this problem, adsorption-biological synergistic purification technology has gradually gained attention, with porous materials (such as zeolite and activated carbon) being widely used for the initial interception of pollutants. However, in practical engineering applications, due to considerations of structural strength and molding processes, binders (such as cement) are often added to construct a stable framework structure. But these traditional binders significantly damage the microporous structure and surface activity of the material, leading to a decrease or even loss of adsorption performance, retaining only a coarse filtration function.

[0003] Furthermore, the synergistic degradation function of microorganisms is becoming increasingly important for the sustainable regeneration of materials. However, most adsorbent materials do not fully consider biocompatibility during the synthesis process, leading to difficulties in microbial attachment and community inactivation in the later stages, thus affecting the reusability of the materials and the long-term water purification effect.

[0004] Therefore, there is an urgent need for a new type of adsorption material that can maintain adsorption activity while also possessing good biocompatibility and mechanical properties. Summary of the Invention

[0005] The purpose of this invention is to provide an adsorption material based on organic and inorganic dual-network crosslinking and its preparation method. Through the organic-inorganic dual-network crosslinking structure, "zero-interference encapsulation" of the original adsorption performance is achieved without the use of traditional cement binders, so as to solve the problem that traditional binders will damage the microporous structure and surface activity of the material in the prior art.

[0006] The present invention is achieved through the following technical solution: First, the present invention provides an adsorption material based on organic and inorganic dual network crosslinking, comprising: adsorption aggregate and network structure, wherein the network structure is configured to coat the adsorption aggregate, and the adsorption aggregate is able to communicate with the external environment; The adsorbent aggregate has a porous structure, and the network structure includes a basic cross-linked network, an inorganic cross-linked network, and an organic cross-linked network. The basic cross-linking network is used to form a flexible matrix outside the adsorbed aggregate, the inorganic cross-linking network is used to strengthen the toughness of the network structure, and the organic cross-linking network is used to improve the anti-swelling ability of the network structure.

[0007] As an alternative implementation, the adsorbent aggregate includes zeolite and / or activated carbon.

[0008] As an optional implementation, the basic cross-linked network comprises a cross-linked network formed by sodium alginate and sodium silicate through ion bridging; The inorganic cross-linked network comprises a multi-point synergistic network formed by metal cations interacting with carboxyl groups and / or siloxane bonds in sodium alginate and sodium silicate through complexation and / or ion bridging. The organic cross-linked network comprises a covalent network formed by the condensation reaction of glutaraldehyde with amino and hydroxyl groups in sodium alginate.

[0009] As an optional implementation, the metal cation includes Ca. 2+ .

[0010] As an optional implementation, the mass ratio of the basic cross-linked network to the adsorbed aggregate is (0.3~0.5):12. As an optional implementation, the mass ratio of sodium alginate to sodium silicate is 2:(1.5~2.5).

[0011] Secondly, this invention also provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking, comprising the following steps: S1: Mix sodium alginate solution and sodium silicate solution to form a gel liquid; S2: Pour the gel liquid into a mold, then add zeolite and / or activated carbon to the mold and stir to disperse the zeolite and / or activated carbon in the gel liquid to obtain a preliminary sample; S3: Add a mixed solution of metal cations and glutaraldehyde to the preliminary sample, and allow it to stand to complete the cross-linking reaction to obtain a liquid sample; S4: Demold and dry the liquid sample to obtain a solid sample.

[0012] As an optional implementation, S4 includes drying the liquid sample until the remaining moisture content is 40-60 wt% before demolding, and then placing it under a pressure of 30-60 kMpa for 2-4 minutes.

[0013] As an optional implementation, the concentration of calcium chloride in the mixed solution in S3 is 1~4wt%, the concentration of glutaraldehyde is 0.5~2wt%, the amount of glutaraldehyde added is 0.8~3wt% of the adsorbent material, and the amount of calcium ions added is 0.6~2.5wt% of the adsorbent material.

[0014] As an optional implementation, in step S2, zeolite and activated carbon are added to the mold and stirred, wherein the mass ratio of zeolite to activated carbon is 2:1.5~2.5.

[0015] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. The adsorbent aggregate provided in this embodiment of the invention has a rich porous structure, which can adsorb and retain pollutants in water, such as organic matter and heavy metal ions. The network structure covers the adsorbent aggregate but retains the connectivity with the external environment, ensuring that pollutants can enter the porous structure for adsorption. The basic cross-linked network provides flexibility and stability. The multi-point synergistic effect in the inorganic cross-linked network enhances the mechanical strength and stability of the material, ensuring that the adsorbent aggregate will not be damaged by mechanical stress during use. The organic cross-linked network improves the anti-swelling ability of the network structure and improves the durability of the material in water.

[0016] 2. In this embodiment of the invention, the adsorbent aggregate uses zeolite and activated carbon, which have a rich porous structure. The basic cross-linking network is formed by sodium alginate (SA) and sodium silicate (Na2SiO3). Sodium alginate provides flexibility, while sodium silicate provides inorganic stability. The carboxyl groups (-COOH) in sodium alginate and the silicon-oxygen bonds (Si-O) in sodium silicate form a preliminary cross-linking network through ion bridging, mainly through physical interactions (ionic bonds and hydrogen bonds), forming a matrix that combines flexibility and inorganic stability. Inorganic cross-linked networks introduce metal ions (such as Ca) 2+ Fe 3+ Cu 2+ MnO x To enhance the resilience of the network structure, metal ions form ion bridges with the carboxyl groups in sodium alginate, thereby increasing the network's mechanical strength and stability. For example, Ca²⁺ ions can form stable ion bridges with the carboxyl groups in sodium alginate. R-COOH+Ca 2+ →R-COO − ⋅Ca 2+ COO − ; The organic cross-linked network enhances its anti-swelling ability through glutaraldehyde and epichlorohydrin. Specifically, the aldehyde group of glutaraldehyde can undergo a condensation reaction with the amino (-NH2) and hydroxyl (-OH) groups in sodium alginate to form covalent bonds. The reaction equation is as follows: R-NH2+OHC-CHO→R-NH-CH2OH+H2O.

[0017] 3. The sodium alginate in the basic cross-linked network of the present invention has good biocompatibility, providing a good environment for microbial attachment and community activity, which helps to achieve sustainable regeneration of materials. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a comparison chart of the COD removal rates of the solid samples prepared in Examples 1-12 and Comparative Examples 1-5 of the present invention; Figure 2 This is a comparison chart of the ammonia nitrogen removal rates of the solid samples prepared in Examples 1-12 and Comparative Examples 1-5 of the present invention; Figure 3 The graph shows the mechanical strength test results of the solid samples prepared in Examples 1-12 and Comparative Examples 1-5 of this invention; Figure 4 This is a comparison chart of the swelling rates of the solid samples prepared in Examples 1-12 and Comparative Examples 1-5 of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0020] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] This invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking, comprising the following: 1. Dissolve sodium alginate Weigh 2g of sodium alginate, add it to 80ml of deionized water, heat to about 30~40°C, and stir until completely dissolved.

[0022] 2. Sodium silicate dissolution Weigh 1.5~2.5g of sodium silicate, add it to 20ml of deionized water, and stir until completely dissolved.

[0023] Slowly add the sodium silicate solution to the sodium alginate solution and continue stirring for 30 minutes to ensure that the two are fully mixed. The mixed solution was allowed to stand for 6 hours to allow the components to react and form a preliminary gel liquid.

[0024] 3. Add zeolite and activated carbon Take 8-12 ml of the above gel liquid, then add 6 g of zeolite and 6 g of activated carbon, and use a magnetic stirrer to stir thoroughly to ensure that the zeolite and activated carbon are evenly distributed in the adhesive. Pour into a 4x4 mold.

[0025] 4. Add calcium chloride and glutaraldehyde solution After the surface of the mixed sample is smooth, slowly drip in 20 ml of a mixed solution of 1-4% calcium chloride and 0.5-2% glutaraldehyde; Ensure that the cross-linking reaction occurs uniformly; After adding the solution, let it stand for 12 hours to complete the cross-linking reaction.

[0026] 5. Pressurization and drying Place the mold in a 60°C oven for semi-drying (i.e., the material still retains some moisture), and then remove it; The semi-dried solid sample is placed under a pressure of 30~60 MPa for 3 minutes. This step helps to enhance the mechanical properties of the material. After maintaining pressure, the sample is demolded and then placed back into the oven to dry completely, resulting in a solid sample.

[0027] Example 1: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking, comprising the following: 1. Dissolve sodium alginate Weigh 2g of sodium alginate, add it to 80ml of deionized water, heat to about 35°C, and stir until completely dissolved.

[0028] 2. Sodium silicate dissolution Weigh 2g of sodium silicate, add it to 20ml of deionized water, and stir until completely dissolved.

[0029] Slowly add the sodium silicate solution to the sodium alginate solution and continue stirring for 30 minutes to ensure that the two are fully mixed. The mixed solution was allowed to stand for 6 hours to allow the components to react and form a preliminary gel liquid.

[0030] 3. Add zeolite and activated carbon Take 10 ml of the above gel liquid; Then add 6g of zeolite and 6g of activated carbon, and use a magnetic stirrer to mix thoroughly to ensure that the zeolite and activated carbon are evenly distributed in the adhesive. Pour into a 4x4 mold.

[0031] 4. Add calcium chloride and glutaraldehyde solution After the surface of the mixed sample is smooth, slowly add 20 ml of a mixed solution of 2.5 wt% calcium chloride and 1.2 wt% glutaraldehyde; Ensure that the cross-linking reaction occurs uniformly; After adding the solution, let it stand for 12 hours to complete the cross-linking reaction.

[0032] 5. Pressurization and drying Place the mold in a 60°C oven for semi-drying (i.e., the material still retains some moisture), and then remove it; The semi-dried solid sample was placed under a pressure of 45 MPa for 3 minutes. This step helps to enhance the mechanical properties of the material. After maintaining pressure, the sample is demolded and then placed back into the oven to dry completely, resulting in a solid sample.

[0033] Example 2: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking, comprising the following: 1. Dissolve sodium alginate Weigh 2g of sodium alginate, add it to 80ml of deionized water, heat to about 30°C, and stir until completely dissolved.

[0034] 2. Sodium silicate dissolution Weigh 1.5g of sodium silicate, add it to 20ml of deionized water, and stir until completely dissolved.

[0035] Slowly add the sodium silicate solution to the sodium alginate solution and continue stirring for 30 minutes to ensure that the two are fully mixed. The mixed solution was allowed to stand for 6 hours to allow the components to react and form a preliminary gel liquid.

[0036] 3. Add zeolite and activated carbon Take 8ml of the above gel liquid, then add 6g of zeolite and 6g of activated carbon, and use a magnetic stirrer to stir thoroughly to ensure that the zeolite and activated carbon are evenly distributed in the adhesive. Pour into a 4x4 mold.

[0037] 4. Add calcium chloride and glutaraldehyde solution After the surface of the mixed sample is smooth, slowly add 20 ml of a mixed solution of 1% calcium chloride and 0.5% glutaraldehyde; Ensure that the cross-linking reaction occurs uniformly; After adding the solution, let it stand for 12 hours to complete the cross-linking reaction.

[0038] 5. Pressurization and drying Place the mold in a 60°C oven for semi-drying (i.e., the material still retains some moisture), and then remove it; The semi-dried solid sample was placed under a pressure of 30 MPa for 3 minutes. This step helps to enhance the mechanical properties of the material. After maintaining pressure, the sample is demolded and then placed back into the oven to dry completely, resulting in a solid sample.

[0039] Example 3: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking, comprising the following: 1. Dissolve sodium alginate Weigh 2g of sodium alginate, add it to 80ml of deionized water, heat to about 40°C, and stir until completely dissolved.

[0040] 2. Sodium silicate dissolution Weigh 2.5g of sodium silicate, add it to 20ml of deionized water, and stir until completely dissolved.

[0041] Slowly add the sodium silicate solution to the sodium alginate solution and continue stirring for 30 minutes to ensure that the two are fully mixed. The mixed solution was allowed to stand for 6 hours to allow the components to react and form a preliminary gel liquid.

[0042] 3. Add zeolite and activated carbon Take 12ml of the above gel liquid, then add 6g of zeolite and 6g of activated carbon, and use a magnetic stirrer to stir thoroughly to ensure that the zeolite and activated carbon are evenly distributed in the adhesive. Pour into a 4x4 mold.

[0043] 4. Add calcium chloride and glutaraldehyde solution After the surface of the mixed sample is smooth, slowly add 20 ml of a mixed solution of 4% calcium chloride and 2% glutaraldehyde; Ensure that the cross-linking reaction occurs uniformly; After adding the solution, let it stand for 12 hours to complete the cross-linking reaction.

[0044] 5. Pressurization and drying Place the mold in a 60°C oven for semi-drying (i.e., the material still retains some moisture), and then remove it; The semi-dried solid sample was placed under a pressure of 60 MPa for 3 minutes. This step helps to enhance the mechanical properties of the material. After maintaining pressure, the sample is demolded and then placed back into the oven to dry completely, resulting in a solid sample.

[0045] Comparative Example 1: A method for preparing an adsorbent material is provided, which differs from Example 1 in that it does not use a basic cross-linking network, an inorganic cross-linking network, or an organic cross-linking network.

[0046] Comparative Example 2: A method for preparing an adsorbent material is provided. The difference from Example 1 is that glutaraldehyde is not added in step 4, while the other steps remain unchanged.

[0047] Comparative Example 3: A method for preparing an adsorbent material is provided. The difference from Example 1 is that calcium chloride is not added in step 4, while the other steps remain unchanged.

[0048] Comparative Example 4: A method for preparing an adsorbent material is provided, the difference from Example 1 is that sodium alginate is replaced with PVA, and the remaining steps remain unchanged.

[0049] Comparative Example 5: A method for preparing an adsorbent material is provided, the difference from Example 1 is that sodium alginate is replaced with CMC, and the remaining steps remain unchanged.

[0050] Example 4: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that 3g of sodium alginate is weighed in step 1 and 3g of sodium silicate is weighed in step 2, while the other steps remain unchanged.

[0051] Example 5: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 4 is that the total mass of sodium alginate and sodium silicate is 6g, and the mass ratio of sodium alginate to sodium silicate is 3:2.

[0052] Example 6: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that the total mass of sodium alginate and sodium silicate is 4g, and the mass ratio of sodium alginate to sodium silicate is 3:2.

[0053] Example 7: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that the concentration of glutaraldehyde in the mixed solution is 5.66 wt%, while the other steps remain unchanged.

[0054] Example 8: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that the concentration of glutaraldehyde in the mixed solution is 23.08 wt%, while the other steps remain unchanged.

[0055] Example 9: This embodiment of the invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that the concentration of calcium chloride in the mixed solution is 5 wt%, while the other steps remain unchanged.

[0056] Example 10: This invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that calcium chloride is replaced with ferric chloride, while the other steps remain unchanged.

[0057] Example 11: This invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that calcium chloride is replaced with copper chloride, while the other steps remain unchanged.

[0058] Example 12: This invention provides a method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking. The difference from Example 1 is that glutaraldehyde is replaced with epichlorohydrin, while the other steps remain unchanged.

[0059] Test The solid samples prepared in Examples 1-12 and Comparative Examples 1-5 were tested for COD removal rate, ammonia nitrogen removal rate, mechanical properties, and swelling rate. The COD removal rate and ammonia nitrogen removal rate were tested using a multi-parameter water quality analyzer. The swelling rate was tested by taking a solid sample and weighing it, denoted as M. 0 (unit: g), placed in a beaker containing distilled water, allows for free swelling, M ∞ To balance the swelling mass (in grams), the calculation formula is as follows: The mechanical properties were tested using a Shimadzu precision electronic universal testing machine. The test results are shown in Table 1 below. Figures 1-4 As shown: Table 1

[0060] From Table 1 and Figures 1-4 It is known that the basic cross-linked network formed by sodium alginate (SA) and sodium silicate (Na2SiO3) can achieve almost lossless COD adsorption capacity and ammonia nitrogen adsorption capacity, which is close to the removal rate under non-cross-linked conditions.

[0061] The mechanical strength of Comparative Example 2, which only has physical cross-linking, is 0.07 MPa, which is lower than 0.1 MPa. The mechanical strength of Comparative Example 3, which only has chemical cross-linking, is 0.06 MPa. The mechanical strength of Example 1, which has both physical and chemical cross-linking, is 0.15 MPa, which is better than the mechanical properties of Comparative Example 1 and Comparative Example 2.

[0062] The uncrosslinked (simple activated carbon + zeolite) COD removal rate is 51.25%, and currently only the SA:Na2SiO3 system can maintain a removal efficiency close to 50%. The CMC:Na2SiO3 crosslinked system has good mechanical strength, but its purification capacity is generally only around 20%, indicating poor performance. The PVA:Na2SiO3 crosslinked system has good mechanical strength and a purification capacity of over 20%, but it is still significantly worse than the 50% removal efficiency of the uncrosslinked system.

[0063] In the same material system, appropriately increasing the swelling ratio helps improve adsorption performance because a higher swelling ratio facilitates the opening of material pores and exposes more active sites, thereby enhancing the diffusion and binding efficiency of pollutants. Simultaneously, the flexible network structure after swelling also facilitates sufficient contact between the material and the liquid phase, improving the overall adsorption capacity and rate. However, a higher swelling ratio is not always better; a reasonable balance must be struck between structural stability and adsorption performance to avoid material collapse, decreased mechanical strength, or difficulty in recycling due to excessive expansion. Therefore, controlling the swelling ratio to a relatively high level within the allowable range of the structure is usually an effective means of improving the performance of adsorption materials. In the embodiments of this invention, chemical crosslinking has a greater advantage in improving the swelling ratio, while physical + chemical crosslinking has more promising application prospects.

[0064] The mass ratio of crosslinking agent to solid aggregate is a key parameter that determines the performance of gel materials. A lower ratio helps to improve adsorption capacity and diffusivity, but it will lead to a loose gel structure and poor mechanical properties. On the other hand, a higher ratio can enhance network rigidity and stability, but may inhibit adsorption capacity due to aggregate embedding and pore blockage. By reasonably controlling this ratio, an optimal balance can be achieved between structural stability and adsorption performance.

[0065] Chemical crosslinking agents are a key means to improve the structural stability and applicability of hydrogels. Crosslinking agents react with hydroxyl or amino groups on polymer chains to form stable covalent bonds and construct a three-dimensional crosslinked network. As the proportion of crosslinking agent increases, the mechanical properties of hydrogels (such as compressive strength and elastic modulus) are significantly improved. However, at the same time, due to network densification, porosity decreases, resulting in a reduction in adsorption capacity and swelling rate. When the proportion of crosslinking agent is too high, the structural rigidity is enhanced but the adsorption rate is slowed down, affecting the function. Conversely, when the proportion of crosslinking agent is too low, the gel becomes easily broken and has poor reusability.

[0066] More specifically, a comparison between Example 4 and Example 1 shows that a higher amount of basic cross-linked network improves mechanical properties, but decreases adsorption performance. A comparison between Examples 5 and 6 and Example 1 shows that when the proportion of sodium alginate in the sodium alginate to sodium silicate ratio is higher, the material's flexibility increases. Sodium alginate is the main component providing flexibility in the system; its increased content makes the matrix more ductile and plastic, and the material's biocompatibility is also improved or maintained at a high level because sodium alginate has good biocompatibility, which is beneficial for microbial attachment and growth, but adsorption performance decreases. Conversely, when the proportion of sodium alginate in the sodium alginate to sodium silicate ratio is lower, inorganic stability decreases. This is because sodium silicate is a key component providing inorganic network stability; when its proportion is relatively reduced, the structural stability of the system may weaken.

[0067] As can be seen from the comparison between Example 7, Example 8, Comparative Example 2 and Example 1, when the glutaraldehyde concentration is too low, due to insufficient cross-linking density, it is difficult for sodium alginate polymer chains to form a complete covalent bond network, resulting in a loose material structure and a significant decrease in mechanical properties. This manifests as weakened compressive strength and elastic modulus, brittleness, poor anti-swelling ability, and excessive swelling in water, leading to instability during repeated adsorption-desorption cycles. When the glutaraldehyde concentration is too high, the system forms an over-crosslinked, dense, and rigid network structure, significantly improving mechanical strength and structural rigidity. However, internal pores are blocked, reducing swelling rate and adsorption capacity. Limited mass transfer slows down the adsorption rate, thereby weakening the material's adsorption efficiency. Therefore, the glutaraldehyde concentration should be controlled within an appropriate range to achieve a balance between strength and adsorption performance. If glutaraldehyde is not added, the material is extremely fragile due to the lack of chemical cross-linking, resulting in a significant decrease in mechanical strength and loss of anti-swelling ability. This manifests as excessive swelling or even disintegration in water. Although the initial adsorption performance may be close to that of a cross-linked system, due to structural instability, it cannot be reused, and long-term adsorption and regeneration performance is significantly reduced.

[0068] As can be seen from the comparison between Example 9, Comparative Example 3 and Example 1, when the calcium chloride concentration is too low, the amount of Ca that can be provided in the system is limited. 2+ Insufficient ion quantity prevents the formation of enough ion bridges between the molecular chains of sodium alginate and sodium silicate, resulting in an incomplete inorganic cross-linking network. This leads to a significant decrease in the material's mechanical strength and toughness, a loose overall structure, and difficulty in maintaining a stable morphology. When the calcium chloride concentration is too high, the Ca in the system... 2+ Excessive ions lead to over-densification of the network structure. While this increases the material's rigidity, it reduces its flexibility, resulting in brittleness. Simultaneously, reduced internal porosity and obstructed mass transfer channels decrease both adsorption capacity and adsorption rate. Without calcium chloride, the material lacks an inorganic cross-linked network and relies solely on organic cross-linking, significantly weakening its mechanical properties. Data shows that Comparative Example 3 (without calcium chloride) has a mechanical strength of only 0.06 MPa, while Example 1 (containing calcium chloride) reaches 0.15 MPa, indicating that Ca... 2+ Ions play a crucial role in enhancing structural strength and stability. Generally speaking, too low a calcium chloride concentration results in a loose structure and insufficient strength, while too high a concentration leads to an overly dense structure and decreased adsorption performance. Therefore, it is necessary to control the concentration within an appropriate range to balance the material's mechanical strength, toughness, and adsorption performance.

[0069] A comparison of Examples 10 and 11 with Example 1 shows that when calcium chloride is replaced with ferric chloride or copper chloride, the experimental results indicate that although the macroscopic mechanical properties do not change significantly, the adsorption performance decreases significantly. The fundamental reason for this is that Fe... 3 + / Cu 2+ The binding affinity with alginate is much greater than that with Ca. 2+This leads to excessive densification of the inorganic cross-linked network, clogging internal pores and hindering the diffusion of pollutants into the internal adsorbed aggregates (such as zeolite and activated carbon); simultaneously, Fe... 3+ / Cu 2+ It may also bind to functional groups on the surface of adsorbed aggregates, passivating active sites and further reducing adsorption efficiency. The reason for the lack of significant improvement in mechanical properties lies in the fact that the system is a multi-network composite structure. The covalent organic cross-linking network formed by glutaraldehyde and the basic sodium alginate / sodium silicate network macroscopically dominate the strength performance, and the enhancement of metal ion cross-linking has limited marginal effect under the existing dominant network; in addition, Fe... 3+ / Cu 2+ Rapid and intense surface cross-linking can easily lead to an uneven structure with a hard outer layer and a soft inner layer, which also limits the improvement of overall strength. Therefore, choosing Ca... 2+ It can maintain a good pore structure and mass transfer channels while ensuring sufficient mechanical strength, and avoid serious loss of adsorption performance.

[0070] A comparison of Example 12 and Example 1 reveals that epichlorohydrin underwent an unexpected and depleting side reaction in this system. The main reason is that the epoxy groups of ECH exhibit high reactivity towards nucleophilic sites (especially hydroxyl groups) in alkaline / neutral aqueous phases. Furthermore, in addition to the hydroxyl groups from sodium alginate, the system also contains a large amount of silanol groups (Si-OH) generated from the hydrolysis of sodium silicate. Experimental evidence and mechanistic inference indicate that the added ECH preferentially reacts with the silanol groups to generate organosiloxane hybrid products, thus "intercepting" the ECH originally intended for crosslinking sodium alginate, resulting in the ineffective formation or severe deficiency of the expected organic crosslinking network. The consequences are twofold: firstly, the material loses the auxiliary organic crosslinking and anti-swelling functions that ECH should provide, leading to a degradation in overall network strength; secondly, the side reaction products can form films or blockages on the surface of the adsorbed aggregate or at the pore inlets, both damaging the aggregate's fixation and hindering pollutants from entering the internal adsorption sites, thus causing a significant decrease in the removal rates of COD, ammonia nitrogen, etc. In summary, ECH cannot exert its expected cross-linking effect in sodium silicate-containing systems. Instead, it weakens the mechanical and adsorption properties of the material by undergoing side reactions with silanol groups.

[0071] Comparing Comparative Examples 4 and 5 with Example 1, it is evident that replacing sodium alginate with polyvinyl alcohol (PVA) or sodium carboxymethyl cellulose (CMC) significantly reduced adsorption performance, although the mechanical properties of the materials remained relatively good, especially the CMC system. The fundamental reason is that neither of these alternative materials can completely replace the key role of sodium alginate in terms of functional group structure and network construction mechanism. For the PVA system, the PVA molecular chain is rich in hydroxyl groups, which can react with glutaraldehyde to form a stable covalent cross-linked network and can form hydrogen bonds with sodium silicate, thus exhibiting high mechanical strength. However, PVA lacks the carboxyl group (–COOH) unique to sodium alginate, failing to provide effective ion exchange and electrostatic adsorption sites, and also unable to form hydrogen bonds with Ca. 2+ The formation of a "cell-like" structure results in the absence of an inorganic cross-linking network, decreased porosity, and a significant reduction in adsorption performance. For the CMC system, although it contains carboxyl and hydroxyl groups, theoretically it can react with Ca... 2+ Ions form crosslinks, but due to the lack of the unique spatial configuration of sodium alginate G-units in the molecular structure, a regular "egg grid" network cannot be formed, resulting in low ion crosslinking efficiency and disordered pore structure. At the same time, the synergistic effect of CMC with sodium silicate and glutaraldehyde can easily lead to excessive crosslinking, causing the network to become dense or the pores to collapse, which seriously hinders the diffusion of pollutants to the adsorbent aggregate.

[0072] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An adsorbent material based on organic and inorganic dual-network crosslinking, characterized in that, include: Adsorbed aggregate and network structure, wherein the network structure is configured to coat the adsorbed aggregate and the adsorbed aggregate is able to communicate with the external environment; The adsorbent aggregate has a porous structure, and the network structure includes a basic cross-linked network, an inorganic cross-linked network, and an organic cross-linked network. The basic cross-linking network is used to form a flexible matrix outside the adsorbed aggregate, the inorganic cross-linking network is used to strengthen the toughness of the network structure, and the organic cross-linking network is used to improve the anti-swelling ability of the network structure.

2. The adsorbent material based on organic and inorganic dual-network crosslinking according to claim 1, characterized in that, The adsorbent aggregate includes zeolite and / or activated carbon.

3. The adsorbent material based on organic and inorganic dual-network crosslinking according to claim 2, characterized in that, The basic cross-linked network includes a cross-linked network formed by sodium alginate and sodium silicate through ion bridging; The inorganic cross-linked network comprises a multi-point synergistic network formed by metal cations interacting with carboxyl groups and / or siloxane bonds in sodium alginate and sodium silicate through complexation and / or ion bridging. The organic cross-linked network comprises a covalent network formed by the condensation reaction of glutaraldehyde with amino and hydroxyl groups in sodium alginate.

4. The adsorbent material based on organic and inorganic dual-network crosslinking according to claim 3, characterized in that, The metal cation includes Ca. 2+ .

5. The adsorbent material based on organic and inorganic dual-network crosslinking according to claim 1, characterized in that, The mass ratio of the basic cross-linked network to the adsorbed aggregate is (0.3~0.5):

12.

6. The adsorbent material based on organic and inorganic dual-network crosslinking according to claim 3, characterized in that, The mass ratio of sodium alginate to sodium silicate is 2:(1.5~2.5).

7. A method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Mix sodium alginate solution and sodium silicate solution to form a gel liquid; S2: Pour the gel liquid into a mold, then add zeolite and / or activated carbon to the mold and stir to disperse the zeolite and / or activated carbon in the gel liquid to obtain a preliminary sample; S3: Add a mixed solution of metal cations and glutaraldehyde to the preliminary sample, and allow it to stand to complete the cross-linking reaction to obtain a liquid sample; S4: Demold and dry the liquid sample to obtain a solid sample.

8. The method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking according to claim 7, characterized in that, S4 includes drying the liquid sample until the remaining moisture content is 40-60 wt% before demolding, and then holding it under a pressure of 30-60 kPa for 2-4 minutes.

9. The method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking according to claim 7, characterized in that, The concentration of calcium chloride in the mixed solution in S3 is 1~4wt%, the concentration of glutaraldehyde is 0.5~2wt%, the amount of glutaraldehyde added is 0.8~3wt% of the adsorbent material, and the amount of calcium ions added is 0.6~2.5wt% of the adsorbent material.

10. The method for preparing an adsorbent material based on organic and inorganic dual-network crosslinking according to claim 7, characterized in that, As described in S2, zeolite and activated carbon are added to the mold and stirred, wherein the mass ratio of zeolite to activated carbon is 2:1.5~2.5.

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