Porous material for groundwater monitoring, and preparation method therefor and use thereof

Abstract

The present application relates to the technical field of groundwater monitoring, and in particular to a porous material for groundwater monitoring, and a preparation method therefor and a use thereof. The preparation method for the porous material provided in the present application comprises the following steps: mixing hydrophobically modified sodium alginate, biochar, a mineral material, a pore-forming agent, and a stabilizer to form a mixed solution; and dropwise adding the mixed solution into a metal salt solution, and performing heat treatment to obtain a porous material. In the present application, the hydrophobically modified sodium alginate used as a capsule wall and the mineral material used as a support structure are compounded with the biochar to form a composite material in the metal salt solution, and during the heat treatment, the composite material forms, under the action of the pore-forming agent, a porous material having multiple channels. The time of retention of the porous material in water can be prolonged by using the characteristic of low solubility of the hydrophobically modified sodium alginate in water, and the porous material can adsorb microorganisms in water by using the adsorption performance of the biochar; in addition, the porous material provides more active sites for the attachment of microorganisms.

Description

A porous material for groundwater monitoring, its preparation method and application

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411897164.9, filed on December 20, 2024, entitled "A porous material for groundwater monitoring and its preparation method and application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of groundwater monitoring technology, specifically to a porous material for groundwater monitoring, its preparation method, and its application. Background Technology

[0004] Groundwater monitoring is a crucial activity, significant for protecting water resources, safeguarding human health, and supporting sustainable development. Groundwater monitoring primarily relies on periodic sampling from monitoring wells, sending samples to laboratories for water quality parameter analysis. These parameters include physicochemical and microbiological parameters. Physicochemical parameters can be quickly and accurately obtained through periodic sampling and testing. The groundwater environment contains a rich and relatively stable microbial community, whose composition reflects the true environment of the groundwater and reveals the pollution status of trace or large amounts of inorganic and organic pollutants. This community has direct and important reference value for guiding in-situ bioremediation, chemical, or physical remediation of groundwater, demonstrating significant practical application prospects and potential. However, due to the low concentration of microorganisms in the samples, microbial indicators typically require pretreatment in the laboratory to reach the required biomass standards before testing. However, even with this complex pretreatment process, the test results often fail to accurately reflect the true information of the groundwater's microbial community. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this application is to overcome the inaccuracy of the results of microbial index determination by sampling in the prior art, thereby providing a porous material for groundwater monitoring, its preparation method and application.

[0006] On the one hand, this application provides a method for preparing a porous material, comprising the following steps: mixing hydrophobically modified sodium alginate, biochar, mineral materials, pore-forming agents and stabilizers to form a mixture; dropping the mixture into a metal salt solution and heat-treating it to obtain a porous material.

[0007] In some embodiments, the mass ratio of the hydrophobically modified sodium alginate, biochar, mineral material, pore-forming agent and stabilizer is 1:1-5:0.1-1:0.1-0.5:0.1-0.5.

[0008] In some embodiments, the heat treatment temperature is 80-120°C and the heat treatment time is 1-3 hours.

[0009] In some embodiments, the mixture is added to the metal salt solution at a rate of 0.1-1 mL / min.

[0010] In some embodiments, the metal salt includes at least one selected from calcium, barium, magnesium, and iron salts.

[0011] Optionally, the metal salt includes at least one of calcium chloride, barium chloride, magnesium sulfate, magnesium nitrate, and ferric sulfate.

[0012] In some embodiments, the concentration of the metal salt in the metal salt solution is 10-50 g / L.

[0013] Optionally, the pore-forming agent includes at least one of urea, ammonium bicarbonate, and ammonium carbonate.

[0014] Optionally, the stabilizer includes at least one of polylactic acid, polyhydroxyalkanoate, and polyethylene terephthalate-1,4-cyclohexanediol ester.

[0015] In some embodiments, the hydrophobically modified sodium alginate is obtained by reacting oxidized sodium alginate with an amidating agent in the presence of a catalyst.

[0016] In some embodiments, the sodium alginate oxidation step includes mixing sodium alginate and an oxidant in the presence of an organic solvent, the reaction being carried out at a temperature of 25-35°C for a duration of 1-5 hours.

[0017] Optionally, the organic solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide, and alcohol solvents.

[0018] Optionally, the oxidant includes sodium periodate.

[0019] Optionally, the amidating agent includes at least one of acrylamide, ethylenediamine, ethanolamine, and n-hexylamine.

[0020] Optionally, the catalyst comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide.

[0021] In some embodiments, the ratio of sodium alginate to organic solvent is 1:20-200, in g:mL.

[0022] In some embodiments, the mass ratio of the organic components of the sodium alginate, oxidant, catalyst, and amidation reagent is 1-5:0.1-0.5:0.1-1:0.1-2.

[0023] In some embodiments, oxidized sodium alginate is reacted with an amidating agent in the presence of a catalyst at a temperature of 100-150°C for a time of 2-5 hours.

[0024] To improve the adsorption capacity of the active material for microorganisms and organic pollutants, in some embodiments, the biochar is prepared by reacting porous biochar and chitosan solution in the presence of a crosslinking agent, wherein the ratio of porous biochar, chitosan and crosslinking agent is 1:0.1-1:0.1-1, in g:g:mL.

[0025] In some embodiments, the porous biochar is prepared by soaking the biochar in an alkaline solution, drying it, and then pyrolyzing it in an inert atmosphere at a temperature of 400-800°C for 2-6 hours.

[0026] Optionally, the biochar includes at least one of straw, sawdust, and fruit shells.

[0027] Optionally, the crosslinking agent includes at least one of glutaraldehyde, glutaric anhydride, and succinic anhydride.

[0028] In some embodiments, the chitosan solution is a mixture of chitosan and glacial acetic acid solution, wherein the ratio of chitosan to glacial acetic acid aqueous solution is 1:25-100 (g:mL), and the concentration of glacial acetic acid aqueous solution is 1-3 vol%.

[0029] To further improve the adsorption performance of the active material, in some embodiments, the biochar preparation step is carried out in a whey protein aqueous solution with a whey protein concentration of 10-100 g / L.

[0030] In some embodiments, the whey protein aqueous solution further includes a surfactant, wherein the mass ratio of whey protein to surfactant is 1000-5000:1, and the surfactant includes at least one of Tween-80, sodium stearate, and sodium dodecyl sulfate.

[0031] In order to maintain the mechanical properties of porous materials, in some embodiments, the mineral material is obtained by reacting the mineral material with an aqueous solution of a cellulose ether compound, followed by solid-liquid separation.

[0032] In some embodiments, the ratio of the mineral material to the aqueous solution of the cellulose ether compound is 1:10-100, in g:mL, and the concentration of the aqueous solution of the cellulose ether compound is 1-5 g / L.

[0033] Optionally, the mineral material includes at least one of sepiolite, attapulgite, and illite.

[0034] Optionally, the cellulose ether compound includes at least one of sodium carboxymethyl cellulose, sodium hydroxyethyl cellulose, and hydroxypropyl cellulose.

[0035] In some embodiments, the mixture formed by the hydrophobically modified sodium alginate, biochar, mineral materials, pore-forming agent and stabilizer further includes a microbial nutrient solution, wherein the mass ratio of the microbial nutrient solution to the hydrophobically modified sodium alginate is 100:1-10.

[0036] To improve the adsorption performance for organic pollutants and further enhance microbial colonization, in some embodiments, the preparation method of the porous material further includes mixing the porous material with an aqueous solution of a silane coupling agent to obtain a modified porous material.

[0037] Optionally, the functional groups of the silane coupling agent include at least one of amino, carboxyl, and thiol groups.

[0038] Optionally, the silane coupling agent includes at least one of silane coupling agent KH-550, silane coupling agent KH-570, and silane coupling agent KH-580.

[0039] The ratio of the porous material to the silane coupling agent aqueous solution is 1:100-150, in g:mL, and the concentration of the silane coupling agent aqueous solution is 1-5wt%.

[0040] On the other hand, this application also provides a porous material prepared by the above-mentioned method for preparing porous materials, which can be applied to groundwater microbial monitoring, microbial screening and organic matter removal.

[0041] The technical solution of this application has the following advantages:

[0042] 1. This application provides a method for preparing a porous material, comprising the following steps: mixing hydrophobically modified sodium alginate, biochar, mineral materials, a pore-forming agent, and a stabilizer to form a mixture; dripping the mixture into a metal salt solution and heat-treating it to obtain the porous material. This application uses hydrophobically modified sodium alginate as the capsule wall and mineral materials as the supporting structure. By compounding it with biochar, a composite material is formed in a metal salt solution. Furthermore, during the heat treatment process, the composite material forms a porous material with multiple channels under the action of the pore-forming agent. The porous material utilizes the low solubility of hydrophobically modified sodium alginate in water, which prolongs the retention time of the porous material in water. It utilizes the adsorption properties of biochar to adsorb microorganisms in water, while the porous material provides more active sites for microbial attachment, effectively adsorbing microorganisms in groundwater and improving the accuracy of groundwater microbial monitoring.

[0043] 2. The method for preparing porous materials provided in this application involves obtaining hydrophobically modified sodium alginate by oxidizing sodium alginate and reacting it with an amidating agent in the presence of a catalyst. This application oxidizes sodium alginate to generate aldehyde groups, which are then reacted with an amidating agent in the presence of a catalyst to obtain hydrophobic sodium alginate amidated derivatives. This reduces the solubility of sodium alginate in water, prolongs its retention time in water, and prevents sodium alginate from dissolving in water within a short period, thus preventing effective attachment of microorganisms.

[0044] 3. The method for preparing porous materials provided in this application involves reacting porous biochar and chitosan solution in the presence of a crosslinking agent. This application modifies porous biochar with chitosan, which on the one hand improves the adsorption performance of biochar for microorganisms, and on the other hand, it can adsorb organic matter in water, thereby removing organic matter from the water.

[0045] 4. The method for preparing porous materials provided in this application further includes a microbial nutrient solution in the mixture formed by the hydrophobically modified sodium alginate, biochar, mineral materials, pore-forming agent, and stabilizer. By adding a microbial nutrient solution to the mixture, this application can embed microbial nutrients within the porous material, promoting the colonization and accumulation of microorganisms in the pores of the porous material.

[0046] 5. The method for preparing porous materials provided in this application, wherein the reaction process in the biochar preparation step is carried out in a whey protein aqueous solution. This application, by adding whey protein to the biochar, can further improve the adhesion of microorganisms or other organic matter to the porous material.

[0047] 6. The method for preparing porous materials provided in this application involves reacting the mineral material with an aqueous solution of sodium carboxymethyl cellulose, followed by solid-liquid separation. This application utilizes sodium carboxymethyl cellulose to modify the mineral material, thereby improving its mechanical properties and supporting strength, enhancing its adhesion to microorganisms, and providing a carbon source for microbial growth.

[0048] 7. The method for preparing porous materials provided in this application further includes mixing the porous material with a silane coupling agent to obtain a modified porous material. This application forms a modified porous material by combining a silane coupling agent with a porous material. The silane coupling agent can improve the adsorption effect on microorganisms and promote their colonization. Furthermore, it can adsorb pollutants through the silane coupling agent, thereby achieving the screening of microorganisms.

[0049] 8. The porous material prepared by the method provided in this application can be used not only for monitoring groundwater microorganisms, but also for removing organic matter from groundwater, and for targeted screening of microorganisms. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0051] Figure 1 is a microscopic morphology diagram of the porous material in Embodiment 1 of this application;

[0052] Figure 2 is a cross-sectional view of the microstructure of the porous material in Embodiment 1 of this application. Detailed Implementation

[0053] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.

[0054] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0055] Example 1

[0056] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0057] (1) Hydrophobic modification of sodium alginate: 5g of sodium alginate was dissolved in 200mL of N,N-dimethylformamide (DNF), 0.1g of sodium periodate was added, and the mixture was stirred at 300rpm for 2h in the dark at 25℃. 0.5g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5g of N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 300rpm for 10min. 2g of acrylamide was added, and the reaction temperature was increased to 100℃. After stirring at 300rpm for 2h, the mixture was centrifuged at 5000rpm for 5min, washed with water, and dried to obtain hydrophobic sodium alginate.

[0058] (2) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, dried and then pyrolyzed in a tube furnace at 600℃ for 3h in an oxygen-deficient environment with a heating rate of 5℃ / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, water-washed, dried and ground through a 200-mesh sieve to obtain porous biochar.

[0059] Add 0.5g of chitosan to 25mL of 1% (v / v) glacial acetic acid solution and stir at 300rpm for 1h to dissolve and obtain chitosan solution.

[0060] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water and stirred at 300 rpm for 1 h to dissolve. Then, 1 g of porous biochar was added and stirred for 1 h to prepare a mixed solution. The mixed solution was added dropwise to a chitosan solution and stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added and stirred at 300 rpm for 10 min. The mixture was then centrifuged and washed with water to obtain the modified porous biochar.

[0061] (3) Modified sepiolite: The sepiolite is acid-washed, washed with water, dried, ground and passed through a 200-mesh sieve.

[0062] Add 0.1g of sodium carboxymethyl cellulose to 100mL of water, heat, and stir at 300rpm to dissolve, thus obtaining a sodium carboxymethyl cellulose solution.

[0063] Add 5g of acidified sepiolite to 100mL of sodium carboxymethyl cellulose solution, stir at 300rpm for 1h, centrifuge at 3000rpm, wash with water and dry to obtain modified sepiolite.

[0064] (4) Preparation of porous materials:

[0065] Prepare a microbial nutrient solution with a trypsin concentration of 100 g / L, a yeast extract concentration of 50 g / L, and a sodium chloride concentration of 100 g / L.

[0066] Add 1g of hydrophobic modified sodium alginate obtained in step (1) to 100g of microbial nutrient solution and stir at 300rpm to dissolve. Add 5g of modified porous biochar obtained in step (2), 0.5g of polylactic acid, 0.5g of modified sepiolite obtained in step (3), and 0.5g of urea. Stir the above materials at 300rpm to form a mixture.

[0067] The mixture was added dropwise to a 50 g / L calcium chloride aqueous solution at a rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80 °C to form a porous material.

[0068] The microstructure of the porous material formed in this embodiment is shown in Figures 1 and 2.

[0069] Example 2

[0070] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0071] Take 1g of the porous material prepared in Example 1 and add it to 100mL of 5% KH-550 aqueous solution of silane coupling agent. Stir and react for 30min to obtain the modified porous material.

[0072] Example 3

[0073] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0074] Take 1g of the porous material prepared in Example 1 and add it to 100mL of 5% KH-570 silane coupling agent. Stir and react for 30min to obtain the modified porous material.

[0075] Example 4

[0076] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0077] Take 1g of the porous material prepared in Example 1 and add it to 100mL of 5% KH-580 silane coupling agent. Stir and react for 30min to obtain the modified porous material.

[0078] Example 5

[0079] This embodiment provides a method for preparing porous materials. The specific steps and parameters are the same as in Example 1. The difference is that step (2) of modifying chitosan biochar is not included. Instead, the active material in step (4) is replaced with an equal mass of unmodified porous biochar (i.e., porous biochar after pyrolysis treatment) from step (1).

[0080] Example 6

[0081] This embodiment provides a method for preparing porous materials. The specific steps and parameters are the same as in Example 1. The difference is that the reaction system of chitosan-modified biochar in step (2) does not contain whey protein and emulsifier, i.e. (2) Modification of active materials: the straw is crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 600℃ in the absence of oxygen for 3h. The heating rate is 5℃ / min and the reaction atmosphere is nitrogen to obtain biochar. The biochar is acid washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0082] Add 0.5g of chitosan to 25mL of 1% (v / v) glacial acetic acid solution and stir for 1h to dissolve and obtain chitosan solution.

[0083] A mixed solution was prepared by adding 1 g of porous biochar to 25 mL of deionized water and stirring for 1 h. The mixed solution was then added dropwise to a chitosan solution and stirred for 1 h. 0.1 mL of glutaraldehyde was added and stirred for 10 min. The modified porous biochar was obtained by centrifugation and washing with water.

[0084] Example 7

[0085] This embodiment provides a method for preparing porous materials. The specific steps and parameters are the same as in Example 1. The difference is that an equal mass of deionized water is used to replace the microbial nutrient solution in step (4).

[0086] Example 8

[0087] This embodiment provides a method for preparing a porous material. The specific steps and parameters are the same as in Example 1. The difference is that an equal mass of unmodified sepiolite is used to replace the modified sepiolite in step (3).

[0088] Example 9

[0089] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0090] (1) Hydrophobic modification of sodium alginate: 5g sodium alginate was dissolved in 100mL dimethyl sulfoxide, 2.5g sodium periodate was added, and the mixture was stirred at 200rpm for 5h in the dark at 35℃. 0.05g 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.05g N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 400rpm for 10min. 2g ethylenediamine was added, the temperature was raised to 150℃, and the mixture was stirred at 600rpm for 2h. After centrifugation at 5000rpm for 5min, the mixture was washed with water and dried to obtain hydrophobic sodium alginate.

[0091] (2) Modification of active materials: The wood chips were crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, dried and then pyrolyzed in a tube furnace at 400℃ for 6h in an oxygen-deficient environment with a heating rate of 5℃ / min and a reaction atmosphere of nitrogen to obtain biochar. The biochar was acid-washed, water-washed, dried and ground through a 200-mesh sieve to obtain porous biochar.

[0092] Add 0.5g of chitosan to 12.5mL of 3% (v / v) glacial acetic acid solution and stir at 300rpm for 1h to dissolve and obtain chitosan solution.

[0093] 0.5g of whey protein and 0.1mg of sodium stearate were added to 50mL of deionized water and stirred at 600rpm for 1h to dissolve. Then, 5g of porous biochar was added and stirred for 1h to prepare a mixed solution. The mixed solution was added dropwise to chitosan solution and stirred at 300rpm for 1h. Then, 1mL of glutaric anhydride was added and stirred at 300rpm for 10min. After centrifugation and washing with water, the modified porous biochar was obtained.

[0094] (3) Modified attapulgite: The attapulgite is acid-washed, water-washed, dried, ground and then passed through a 200-mesh sieve.

[0095] Add 0.5g of sodium hydroxyethyl cellulose to 100mL of water, heat, and stir at 300rpm to dissolve, thus obtaining a sodium hydroxyethyl cellulose solution.

[0096] Add 5g of acidified attapulgite to 50mL of sodium hydroxyethyl cellulose solution, stir at 300rpm for 1h, centrifuge at 3000rpm, wash with water and dry to obtain modified attapulgite.

[0097] (4) Preparation of porous materials:

[0098] Prepare a microbial nutrient solution with a trypsin concentration of 100 g / L, a yeast extract concentration of 50 g / L, and a sodium chloride concentration of 100 g / L.

[0099] Add 5g of the hydrophobic modified sodium alginate prepared in step (1) to 10g of microbial nutrient solution and stir at 300rpm to dissolve. Add 5g of the modified porous biochar prepared in step (2), 0.5g of polyhydroxy fatty acid ester, 0.5g of the modified sepiolite prepared in step (3), and 0.5g of ammonium bicarbonate. Stir the above materials at 300rpm to form a mixture.

[0100] The mixture was added dropwise to a 10 g / L barium chloride aqueous solution at a rate of 1 mL / min, and stirred at 400 rpm for 1 h at 120 °C to form a porous material.

[0101] Take 1g of porous material and add it to 150mL of 1% KH570 silane coupling agent. Stir and react for 30min to obtain the modified porous material.

[0102] Example 10

[0103] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0104] (1) Hydrophobic modification of sodium alginate: 5g sodium alginate was dissolved in 1000mL anhydrous ethanol, 0.1g sodium periodate was added, and the mixture was stirred at 300rpm for 2h in the dark at 25℃. 0.5g 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5g N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 300rpm for 10min. 0.1g ethanolamine was added, and the reaction temperature was increased to 100℃. After stirring at 300rpm for 5h, the mixture was centrifuged at 5000rpm for 5min, washed with water, and dried to obtain hydrophobic sodium alginate.

[0105] (2) Modification of active materials: The fruit shell was crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, dried and then pyrolyzed in a tube furnace at 800℃ for 2h in an oxygen-deficient environment with a heating rate of 5℃ / min and a reaction atmosphere of nitrogen to obtain biochar. The biochar was acid-washed, water-washed, dried and ground through a 200-mesh sieve to obtain porous biochar.

[0106] Add 1g of chitosan to 100mL of 2% (v / v) glacial acetic acid solution and stir at 300rpm for 1h to dissolve and obtain chitosan solution.

[0107] 1g of whey protein and 0.5mg of sodium dodecyl sulfate were added to 100mL of deionized water and stirred at 300rpm for 1h to dissolve. Then, 1g of porous biochar was added and stirred for 1h to prepare a mixed solution. The mixed solution was added dropwise to chitosan solution and stirred at 300rpm for 1h. Then, 1mL of succinic anhydride was added and stirred at 300rpm for 10min. After centrifugation and washing with water, modified porous biochar was obtained.

[0108] (3) Modified sepiolite: illite is acid-washed, washed with water, dried, ground and passed through a 200-mesh sieve.

[0109] Add 1g of hydroxypropyl cellulose to 100mL of water, heat, and stir at 200rpm to dissolve, thus obtaining a hydroxypropyl cellulose solution.

[0110] Add 5g of acidified illite to 100mL of hydroxypropyl cellulose solution, stir at 400rpm for 1h, centrifuge at 3000rpm, wash with water and dry to obtain modified illite.

[0111] (4) Preparation of porous materials:

[0112] Prepare a microbial nutrient solution with a trypsin concentration of 100 g / L, a yeast extract concentration of 50 g / L, and a sodium chloride concentration of 100 g / L.

[0113] Add 1g of hydrophobic modified sodium alginate obtained in step (1) to 100g of microbial nutrient solution and stir at 300rpm to dissolve. Add 5g of modified porous biochar obtained in step (2), 0.5g of polyethylene terephthalate-1,4-cyclohexanediol ester, 0.5g of modified illite obtained in step (3), and 0.5g of urea. Stir the above materials at 300rpm to form a mixture.

[0114] The mixture was added dropwise to a 50 g / L magnesium nitrate aqueous solution at a rate of 0.1 mL / min, and stirred at 400 rpm for 3 h at 100 °C to form a porous material.

[0115] 1g of porous material was added to 120mL of 3% KH570 silane coupling agent and stirred for 30min to obtain the modified porous material.

[0116] Example 11

[0117] This embodiment provides a method for preparing porous materials, with the specific steps and parameters as follows:

[0118] (1) Hydrophobic modification of sodium alginate: 5g sodium alginate was dissolved in 200mL isopropanol, 0.1g sodium periodate was added, and the mixture was stirred at 600rpm for 2h in the dark at 25℃. 0.5g 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5g N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 200rpm for 10min. 2g n-hexylamine was added, and the reaction temperature was increased to 100℃. After stirring at 400rpm for 2h, the mixture was centrifuged at 5000rpm for 5min, washed with water, and dried to obtain hydrophobic sodium alginate.

[0119] (2) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, dried and then pyrolyzed in a tube furnace at 600℃ for 3h in an oxygen-deficient environment with a heating rate of 5℃ / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, water-washed, dried and ground through a 200-mesh sieve to obtain porous biochar.

[0120] Add 0.5g of chitosan to 25mL of 1% (v / v) glacial acetic acid solution and stir at 300rpm for 1h to dissolve and obtain chitosan solution.

[0121] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water and stirred at 300 rpm for 1 h to dissolve. Then, 1 g of porous biochar was added and stirred for 1 h to prepare a mixed solution. The mixed solution was added dropwise to a chitosan solution and stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added and stirred at 300 rpm for 10 min. The mixture was then centrifuged and washed with water to obtain the modified porous biochar.

[0122] (3) Modified sepiolite: The sepiolite is acid-washed, washed with water, dried, ground and passed through a 200-mesh sieve.

[0123] Add 0.1g of sodium carboxymethyl cellulose to 100mL of water, heat, and stir at 300rpm to dissolve, thus obtaining a sodium carboxymethyl cellulose solution.

[0124] Add 5g of acidified sepiolite to 100mL of sodium carboxymethyl cellulose solution, stir at 300rpm for 1h, centrifuge at 3000rpm, wash with water and dry to obtain modified sepiolite.

[0125] (4) Preparation of porous materials:

[0126] Prepare a microbial nutrient solution with a trypsin concentration of 100 g / L, a yeast extract concentration of 50 g / L, and a sodium chloride concentration of 100 g / L.

[0127] Add 1g of hydrophobic modified sodium alginate obtained in step (1) to 100g of microbial nutrient solution and stir at 300rpm to dissolve. Add 5g of modified porous biochar obtained in step (2), 0.5g of polylactic acid, 0.5g of modified sepiolite obtained in step (3), and 0.5g of urea. Stir the above materials at 300rpm to form a mixture.

[0128] The mixture was added dropwise to a 50 g / L calcium chloride aqueous solution at a rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80 °C to form a porous material.

[0129] Comparative Example

[0130] This comparative example provides a method for preparing a porous material. The specific steps and parameters are the same as those in Example 1. The difference is that step (1) in the example is not included, and an equal mass of unmodified sodium alginate is used to replace the hydrophobically modified sodium alginate in step (4) of Example 1.

[0131] The specific steps are as follows:

[0132] (1) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2g / LNaCO3, dried and then pyrolyzed in a tube furnace at 600℃ for 3h in an oxygen-deficient environment with a heating rate of 5℃ / min and a reaction atmosphere of nitrogen to obtain biochar. The biochar was acid-washed, water-washed, dried and ground through a 200-mesh sieve to obtain porous biochar.

[0133] Add 0.5g of chitosan to 25mL of 1% (v / v) glacial acetic acid solution and stir at 300rpm for 1h to dissolve and obtain chitosan solution.

[0134] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water and stirred at 300 rpm for 1 h to dissolve. Then, 1 g of porous biochar was added and stirred for 1 h to prepare a mixed solution. The mixed solution was added dropwise to a chitosan solution and stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added and stirred at 300 rpm for 10 min. The mixture was then centrifuged and washed with water to obtain the modified porous biochar.

[0135] (2) Modified sepiolite: The sepiolite was acid-washed, washed with water, dried, ground and passed through a 200-mesh sieve.

[0136] Add 0.1g of sodium carboxymethyl cellulose to 100mL of water, heat, and stir at 300rpm to dissolve, thus obtaining a sodium carboxymethyl cellulose solution.

[0137] Add 5g of acidified sepiolite to 100mL of sodium carboxymethyl cellulose solution, stir at 300rpm for 1h, centrifuge at 3000rpm, wash with water and dry to obtain modified sepiolite.

[0138] (3) Preparation of porous materials:

[0139] Prepare a microbial nutrient solution with a trypsin concentration of 100 g / L, a yeast extract concentration of 50 g / L, and a sodium chloride concentration of 100 g / L.

[0140] Add 1g of sodium alginate to 100g of microbial nutrient solution and stir at 300rpm to dissolve. Add 5g of modified porous biochar prepared in step (2), 0.5g of polylactic acid, 0.5g of modified sepiolite prepared in step (3), and 0.5g of urea. Stir the above materials at 300rpm to form a mixture.

[0141] The mixture was added dropwise to a 50 g / L calcium chloride aqueous solution at a rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80 °C to form a porous material.

[0142] Application Example 1

[0143] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0144] 20g of the modified porous material prepared in Example 1 was placed in a 5×5cm filter bag and then placed in a groundwater monitoring well. After 60 days, the bag was removed and the microbial community information was detected.

[0145] Application Example 2

[0146] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0147] 20g of the modified porous material prepared in Example 2 was placed in a 5×5cm filter bag and then placed in a groundwater monitoring well. After 60 days, the bag was removed and the microbial community information was detected.

[0148] Application Example 3

[0149] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0150] 20g of the modified porous material prepared in Example 3 was placed in a 5×5cm filter bag and then placed in a groundwater monitoring well. After 60 days, the bag was removed and the microbial community information was detected.

[0151] Experimental Example 1

[0152] A 1% (v / v) seed culture of Pseudomonas nitroreducens was inoculated into 250 mL of culture medium. The strain was deposited at the China General Microbiological Culture Collection Center with accession number CGMCC 1.8737.

[0153] Add 0.5 g of porous material to the seed culture, fix continuously at 200 rpm in a shaker at 25℃ for 48 h, let stand to separate solid and liquid for 12 h, centrifuge at 4000 r / min for 10 min, remove supernatant, add physiological saline, centrifuge at 4000 r / min for 10 min, repeat twice, dry to constant weight, and determine the microbial adsorption capacity of porous material based on the weight difference between the dried material and the porous material, as shown in Table 1.

[0154] The porous materials used are those prepared in Examples 1-8 and the comparative examples.

[0155] Table 1 Adsorption capacity of porous materials for microorganisms

[0156] According to the data in Table 1, compared with the comparative example which used unmodified sodium alginate as the raw material for porous materials, the porous materials prepared by hydrophobically modified sodium alginate in this application can improve the adsorption capacity of microorganisms. At the same time, compared with Examples 5-8, the porous materials prepared by modifying porous biochar, combining porous biochar with whey protein, modifying sepiolite, and adding microbial nutrient solution in Examples 1-4 of this application can achieve a microbial adsorption capacity of more than 40 mg / g.

[0157] Experimental Example 2

[0158] A 1% (v / v) seed culture of Pseudomonas nitroreducens was inoculated into 250 mL of culture medium. The strain was deposited at the China General Microbiological Culture Collection Center with accession number CGMCC 1.8737.

[0159] Add 0.5g of porous material to the seed culture and fix it continuously in a shaker at 200rpm for 60 days at 25℃. Let it stand to separate the solid and liquid for 12h, centrifuge at 4000r / min for 10min, remove the supernatant, add physiological saline, centrifuge at 4000r / min for 10min, repeat twice, and dry to constant weight. The amount of microorganism adsorbed by the porous material is determined based on the weight difference between the dried material and the porous material, as shown in Table 2.

[0160] The porous materials used are those prepared in Examples 1-8 and the comparative examples.

[0161] Table 2 Adsorption capacity of porous materials for microorganisms

[0162] According to the data in Table 2, compared with the comparative example which used unmodified sodium alginate as the raw material for porous materials, the porous materials prepared by this application using hydrophobically modified sodium alginate can maintain the structural integrity of the porous materials and achieve long-term microbial adsorption within a 60-day treatment period. In contrast, the porous materials prepared by the comparative example using unmodified sodium alginate gradually dissolve in water after about 20 days, and the microbial adsorption effect is extremely poor.

[0163] Experimental Example 3

[0164] Take a 100mL conical flask, add 0.05g of porous material and 50mL of 20mg / L tetracycline solution, and shake at a constant speed of 300rpm in a horizontal shaker for 2h. The porous material is the porous material prepared in Examples 1-4.

[0165] Take a 100mL conical flask, add 0.05g of porous material and 50mL of 20mg / L naphthalene solution, and shake in a horizontal shaker at a constant speed of 300rpm for 2h. The porous material is the porous material prepared in Examples 1-4.

[0166] Take a 100mL conical flask, add 0.05g of porous material and 50mL of 20mg / L patulin solution, and shake in a horizontal shaker at a constant speed of 300rpm for 2h. The porous material is the porous material prepared in Examples 1-4.

[0167] After adsorption, the filtrate was collected, filtered through a membrane, and the naphthalene concentration was determined using PT-GC-MS (PT: TEM-Atomx, Agilent Technologies, Inc., USA; GC-MS: Agilent Technologies, Inc., USA). The determination method was "HJ 639-2012 Determination of Volatile Organic Compounds in Water by Purge-Trap / Gas Chromatography-Mass Spectrometry". Tetracycline and patulin were mainly determined using LC-MS (Agilent Technologies, Inc., USA). The determination method was based on the literature Xu, Xu, et al. "Ionic liquid-based microwave-assisted dispersive liquid–liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma." Analytica Chimica Acta 707.1-2 (2011):0-99 and the literature Yin Juyi et al. "Determination of Patulin Residues in Concentrated Apple Juice by High Performance Liquid Chromatography." Journal of Analytical Science 23.1 (2007):3.

[0168] The experiment was repeated three times, and the adsorption amount was taken as the average of the three repetitions. The results are shown in Table 3.

[0169] Table 3 Adsorption capacity of porous materials for organic pollutants

[0170] As shown in Table 3, this application can improve the adsorption capacity of organic pollutants by using composite silane coupling agents on the basis of porous materials. In particular, the adsorption capacity of a certain organic pollutant can be improved by selecting the silane coupling agent material in a targeted manner, which provides convenience for targeted screening of microbial strains for the remediation of specific organic pollutants.

[0171] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a porous material, characterized in that, Includes the following steps, A mixture is formed by mixing hydrophobically modified sodium alginate, biochar, mineral materials, pore-forming agents and stabilizers; The mixture is added dropwise to a metal salt solution and then heat-treated to obtain a porous material.

2. The method for preparing porous materials according to claim 1, characterized in that, The hydrophobically modified sodium alginate is obtained by reacting oxidized sodium alginate with an amidating agent in the presence of a catalyst; and / or, The mixture formed by the hydrophobically modified sodium alginate, biochar, mineral materials, pore-forming agent and stabilizer also includes a microbial nutrient solution, wherein the mass ratio of the microbial nutrient solution to the hydrophobically modified sodium alginate is 100:1-10.

3. The method for preparing porous materials according to claim 2, characterized in that, The steps of sodium alginate oxidation include mixing sodium alginate and an oxidant in the presence of an organic solvent, wherein the reaction temperature is 25-35°C, and the reaction time is 1-5 hours; and / or, The amidating agent includes at least one selected from acrylamide, ethylenediamine, ethanolamine, and n-hexylamine; and / or, The catalyst comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide; and / or, Oxidized sodium alginate reacts with an amidating agent in the presence of a catalyst at a temperature of 100-150°C for 2-5 hours; and / or, The biochar is prepared by reacting porous biochar and chitosan solution in the presence of a crosslinking agent. The ratio of porous biochar, chitosan and crosslinking agent is 1:0.1-1:0.1-1, with units of g:g:mL.

4. The method for preparing porous materials according to claim 3, characterized in that, The mass ratio of the organic components of the sodium alginate, oxidant, catalyst, and amidation reagent is 1-5:0.1-0.5:0.1-1:0.1-2; and / or, The organic solvent includes at least one selected from N,N-dimethylformamide, dimethyl sulfoxide, and alcohol solvents; and / or, The oxidant includes sodium periodate; and / or, The ratio of sodium alginate to organic solvent is 1:20-200, in g:mL; and / or, The crosslinking agent includes at least one of glutaraldehyde, glutaric anhydride, and succinic anhydride; and / or, The chitosan solution is a mixture of chitosan and glacial acetic acid solution, wherein the ratio of chitosan to glacial acetic acid aqueous solution is 1:25-100, in g:mL, and the concentration of the glacial acetic acid aqueous solution is 1-3 vol%; and / or, In the preparation step of the biochar, the reaction process is carried out in a whey protein aqueous solution, wherein the whey protein concentration in the whey protein aqueous solution is 10-100 g / L; and / or, The mineral material is obtained by reacting the mineral material with an aqueous solution of a cellulose ether compound, followed by solid-liquid separation; and / or, The porous biochar is prepared by soaking the biochar in an alkaline solution, drying it, and then pyrolyzing it in an inert atmosphere at a temperature of 400-800℃ for 2-6 hours.

5. The method for preparing porous materials according to claim 4, characterized in that, The whey protein aqueous solution further includes a surfactant, wherein the mass ratio of whey protein to surfactant is 1000-5000:1, and the surfactant includes at least one selected from Tween-80, sodium stearate, and sodium dodecyl sulfate; and / or The ratio of the mineral material to the aqueous solution of the cellulose ether compound is 1:10-100, in g:mL, and the concentration of the aqueous solution of the cellulose ether compound is 1-5 g / L; and / or, The cellulose ether compound includes at least one of sodium carboxymethyl cellulose, sodium hydroxyethyl cellulose, and hydroxypropyl cellulose; and / or, The concentration of the metal salt in the metal salt solution is 10-50 g / L; and / or, The pore-forming agent includes at least one selected from urea, ammonium bicarbonate, and ammonium carbonate; and / or, The biochar includes at least one of straw, sawdust, and fruit shells; and / or, The mineral material includes at least one of sepiolite, attapulgite, and illite.

6. The method for preparing porous materials according to any one of claims 1-5, characterized in that, The mass ratio of the hydrophobically modified sodium alginate, biochar, mineral material, pore-forming agent, and stabilizer is 1:1-5:0.1-1:0.1-0.5:0.1-0.5; and / or, The heat treatment temperature is 80-120℃, and the heat treatment time is 1-3 hours; and / or, The mixing solution is added to the metal salt solution at a rate of 0.1-1 mL / min; and / or, The metal salt includes at least one selected from calcium, barium, magnesium, and iron salts; and / or, The stabilizer includes at least one of polylactic acid, polyhydroxyalkanoate, and polyethylene terephthalate-1,4-cyclohexanediol ester.

7. The method for preparing porous materials according to any one of claims 1-6, characterized in that, The method for preparing the porous material further includes mixing the porous material with an aqueous solution of a silane coupling agent to obtain a modified porous material.

8. The method for preparing porous materials according to claim 7, characterized in that, The functional groups of the silane coupling agent include at least one selected from amino, carboxyl, and mercapto groups; and / or, The ratio of the porous material to the silane coupling agent aqueous solution is 1:100-150, in g:mL, and the concentration of the silane coupling agent aqueous solution is 1-5wt%.

9. A porous material, characterized in that, It is prepared by the method for preparing porous materials according to any one of claims 1-8.

10. The application of the porous material of claim 9 in groundwater microbial monitoring, microbial screening and organic matter removal.

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