Porous material for underground water monitoring and preparation method and application thereof

Abstract

The invention relates to the technical field of underground water monitoring, in particular to a porous material for underground water monitoring and a preparation method and application thereof. The preparation method of the porous material provided by the invention comprises the following steps: mixing hydrophobic modified sodium alginate, charcoal, a mineral material, a pore-forming agent and a stabilizer to form a mixed solution; dropwise adding the mixed solution into a metal salt solution, and performing heat treatment to obtain the porous material. Hydrophobic modified sodium alginate is used as a capsule wall, a mineral material is used as a supporting structure, the hydrophobic modified sodium alginate and the mineral material are compounded with charcoal, a composite material is formed in a metal salt solution, and in the heat treatment process, the composite material forms a porous material with multiple pore channels under the action of a pore-forming agent; the porous material can prolong the retention time of the porous material in water by utilizing the characteristic of low solubility of hydrophobic modified sodium alginate in water, adsorbs microorganisms in water by utilizing the adsorption performance of biochar, and provides more active sites for attachment of the microorganisms at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of groundwater monitoring, and in particular to a porous material for groundwater monitoring and a preparation method and application thereof. Background Art

[0002] Groundwater monitoring is a very important activity. It is of great significance for protecting water resources, ensuring human health, and supporting sustainable development. Groundwater monitoring mainly relies on regular sampling of monitoring wells and sending samples to the laboratory for analysis of water quality parameters. Water quality parameters include physical and chemical parameters and microbial parameters. Among them, physical and chemical parameters can be quickly and accurately obtained through regular sampling and testing. There are rich and relatively stable microbial flora in the groundwater environment. The composition of their communities reflects the real environment in the groundwater and can reveal the pollution of trace or large amounts of inorganic and organic pollutants. They have direct and important reference value for guiding in situ bioremediation, chemical or physical remediation of groundwater, and show great practical application prospects and potential. However, due to the low concentration of microorganisms in the sampling, when testing microbial indicators, it is usually necessary to pre-treat them in the laboratory to meet the biomass standards required for detection before testing. However, through the complicated pretreatment process, the test results often cannot accurately reflect the true information of the microbial flora in the groundwater. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect of inaccurate results of measuring microbial indicators by sampling in the prior art, thereby providing a porous material for groundwater monitoring and a preparation method and application thereof.

[0004] On the one hand, the present invention 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 mixed solution; dropping the mixed solution into a metal salt solution, and heat treating it to obtain a porous material.

[0005] In some of the embodiments, the mass ratio of the hydrophobically modified sodium alginate, biochar, mineral material, pore former and stabilizer is 1:1-5:0.1-1:0.1-0.5:0.1-0.5.

[0006] In some embodiments, the heat treatment temperature is 80-120° C., and the heat treatment time is 1-3 h.

[0007] In some embodiments, the mixed solution is dripped into the metal salt solution at a rate of 0.1-1 mL / min.

[0008] In some embodiments, the metal salt includes at least one of a calcium salt, a barium salt, a magnesium salt and an iron salt.

[0009] Preferably, the metal salt includes at least one of calcium chloride, barium chloride, magnesium sulfate, magnesium nitrate and iron sulfate.

[0010] In some embodiments, the concentration of the metal salt in the metal salt solution is 10-50 g / L.

[0011] Preferably, the pore former includes at least one of urea, ammonium bicarbonate and ammonium carbonate.

[0012] Preferably, the stabilizer includes at least one of polylactic acid, polyhydroxyalkanoate, and polyethylene terephthalate-1,4-cyclohexanedimethanol.

[0013] In some embodiments, the hydrophobically modified sodium alginate is obtained by reacting oxidized sodium alginate with an amidation agent in the presence of a catalyst.

[0014] In some embodiments, the step of oxidizing sodium alginate includes mixing sodium alginate and an oxidant for reaction in the presence of an organic solvent, the reaction temperature is 25-35° C., and the mixing reaction time is 1-5 hours.

[0015] Preferably, the organic solvent includes at least one of N,N-dimethylformamide, dimethyl sulfoxide and an alcohol solvent.

[0016] Preferably, the oxidizing agent comprises sodium periodate.

[0017] Preferably, the amidation agent includes at least one of acrylamide, ethylenediamine, ethanolamine and n-hexylamine.

[0018] Preferably, the catalyst comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide.

[0019] In some embodiments, the ratio of sodium alginate to organic solvent is 1:20-200, in units of g:mL.

[0020] In some of the embodiments, the mass ratio of the organic matter of the sodium alginate, the oxidant, the catalyst and the amidation agent is 1-5:0.1-0.5:0.1-1:0.1-2.

[0021] In some of the embodiments, the oxidized sodium alginate is reacted with an amidation agent in the presence of a catalyst, the reaction temperature is 100-150° C., and the reaction time is 2-5 h.

[0022] In order to improve the adsorption of active materials to microorganisms and organic pollutants, in some embodiments, the biochar is prepared by reacting porous biochar and chitosan solution in the presence of a cross-linking agent, and the ratio of the porous biochar, chitosan and cross-linking agent is 1:0.1-1:0.1-1, and the unit is g:g:mL.

[0023] In some of the embodiments, the porous biochar is prepared by soaking the biochar in an alkaline solution, drying it, and pyrolyzing it in an inert atmosphere. The pyrolysis temperature is 400-800° C., and the pyrolysis time is 2-6 hours.

[0024] Preferably, the biochar comprises at least one of straw, wood chips, and fruit shells.

[0025] Preferably, the cross-linking agent includes at least one of glutaraldehyde, glutaric anhydride and succinic anhydride.

[0026] In some embodiments, the chitosan solution is a mixture of chitosan and glacial acetic acid solution, 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%.

[0027] In order to further improve the adsorption performance of the active material, in some embodiments, in the biochar preparation step, the reaction process is carried out in a whey protein aqueous solution, and the whey protein concentration in the whey protein aqueous solution is 10-100 g / L.

[0028] In some embodiments, the whey protein aqueous solution further includes a surfactant, the mass ratio of the whey protein to the surfactant is 1000-5000:1, and the surfactant includes at least one of Tween-80, sodium stearate, and sodium dodecyl sulfate.

[0029] In order to maintain the mechanical properties of the porous material, in some embodiments, the mineral material is obtained by reacting the mineral material with an aqueous solution of a cellulose ether compound and separating the solid from the liquid.

[0030] In some embodiments, the ratio of the mineral material to the aqueous solution of the cellulose ether compound is 1:10-100, expressed in g:mL, and the concentration of the aqueous solution of the cellulose ether compound is 1-5 g / L.

[0031] Preferably, the mineral material includes at least one of sepiolite, attapulgite and illite.

[0032] Preferably, the cellulose ether compound includes at least one of sodium carboxymethyl cellulose, sodium hydroxyethyl cellulose and hydroxypropyl cellulose.

[0033] In some embodiments, the mixed solution formed by the hydrophobically modified sodium alginate, biochar, mineral material, pore former and stabilizer also includes a microbial nutrient solution, and the mass ratio of the microbial nutrient solution to the hydrophobically modified sodium alginate is 100:1-10.

[0034] In order to improve the adsorption performance of organic pollutants and further improve microbial colonization, in some embodiments, the method for preparing the porous material also includes mixing the porous material and an aqueous solution of a silane coupling agent to obtain a modified porous material.

[0035] Preferably, the functional group of the silane coupling agent includes at least one of an amine group, a carboxyl group and a thiol group.

[0036] More preferably, 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.

[0037] 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%.

[0038] On the other hand, the present invention also provides a porous material prepared by the above-mentioned method for preparing a porous material, which can be applied to groundwater microbial monitoring, microbial screening and organic matter removal.

[0039] The technical solution of the present invention has the following advantages:

[0040] 1. A method for preparing a porous material provided by the present invention comprises the following steps: mixing hydrophobically modified sodium alginate, biochar, mineral material, pore former and stabilizer to form a mixed solution; dropping the mixed solution into a metal salt solution, and heat treating the mixed solution to obtain a porous material. The present invention uses hydrophobically modified sodium alginate as a capsule wall and a mineral material as a supporting structure, and forms a composite material in a metal salt solution by compounding with biochar. Furthermore, during the heat treatment process, the composite material forms a porous material with multiple pores under the action of the pore former. The porous material utilizes the low solubility of hydrophobically modified sodium alginate in water to extend the retention time of the porous material in water, and utilizes the adsorption performance of biochar to adsorb microorganisms in water. At the same time, the porous material can provide more active sites for the attachment of microorganisms, effectively adsorb microorganisms in groundwater, and improve the accuracy of groundwater microbial monitoring.

[0041] 2. The preparation method of the porous material provided by the present invention, wherein the hydrophobically modified sodium alginate is obtained by oxidizing sodium alginate and reacting it with an amidating agent in the presence of a catalyst. The present invention generates an aldehyde group by oxidizing sodium alginate, and reacts it with an amidating agent in the presence of a catalyst to obtain a hydrophobic sodium alginate amidated derivative, thereby reducing the solubility of sodium alginate in water, prolonging its retention time in water, and preventing sodium alginate from dissolving in water in a short period of time, thereby preventing microorganisms from effectively attaching.

[0042] 3. The preparation method of the porous material provided by the present invention, wherein the biochar is prepared by reacting the porous biochar and chitosan solution in the presence of a cross-linking agent. The present invention modifies the porous biochar with chitosan, which can improve the adsorption performance of the biochar on microorganisms on the one hand, and can also adsorb organic matter in water on the other hand, thereby removing organic matter from the water.

[0043] 4. The method for preparing the porous material provided by the present invention, wherein the mixed solution formed by the hydrophobically modified sodium alginate, biochar, mineral material, pore-forming agent and stabilizer also includes a microbial nutrient solution. The present invention can embed microbial nutrients in the porous material by adding the microbial nutrient solution to the mixed solution, thereby promoting the colonization and enrichment of microorganisms in the pores of the porous material.

[0044] 5. In the method for preparing the porous material provided by the present invention, in the step of preparing the biochar, the reaction process is carried out in a whey protein aqueous solution. The present invention can further improve the adhesion of microorganisms or other organic matter to the porous material by adding whey protein to the biochar.

[0045] 6. The method for preparing the porous material provided by the present invention, wherein the mineral material is obtained by reacting the mineral material with an aqueous solution of sodium carboxymethyl cellulose and separating the solid from the liquid. The present invention uses sodium carboxymethyl cellulose to modify the mineral material, which can improve the mechanical properties of the mineral material and its supporting capacity, and can also improve the adhesion of microorganisms and provide a carbon source for the growth of microorganisms.

[0046] 7. The method for preparing the porous material provided by the present invention further comprises mixing the porous material with a silane coupling agent to obtain a modified porous material. The present invention forms a modified porous material by compounding the silane coupling agent with the porous material. The silane coupling agent can improve the adsorption effect of microorganisms and promote the colonization of microorganisms on the one hand, and on the other hand, the silane coupling agent can adsorb pollutants to achieve the screening of microorganisms.

[0047] 8. The porous material prepared by the preparation method of the porous material provided by the present invention can be used not only for monitoring groundwater microorganisms, but also for removing groundwater organic matter, and can also be used for directional screening of microorganisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 is a microscopic morphology diagram of the porous material in Example 1 of the present invention;

[0050] Figure 2 It is a cross-sectional view of the microscopic morphology of the porous material in Example 1 of the present invention. DETAILED DESCRIPTION

[0051] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0052] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0053] Example 1

[0054] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0055] (1) Hydrophobic modification of sodium alginate: 5 g of sodium alginate was dissolved in 200 mL of N,N-dimethylformamide (DNF), 0.1 g of sodium periodate was added, and the mixture was stirred at 300 rpm for 2 h at 25 °C in the dark. 0.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5 g of N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 300 rpm for 10 min. 2 g of acrylamide was added, and the reaction temperature was increased to 100 °C. The mixture was stirred at 300 rpm for 2 h, and then the mixture was centrifuged at 5000 rpm for 5 min, washed with water, and dried to obtain hydrophobicized sodium alginate.

[0056] (2) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 600 °C for 3 h with a heating rate of 5 °C / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0057] 0.5 g of chitosan was added into 25 mL of 1% by volume glacial acetic acid solution, and the solution was dissolved by stirring at 300 rpm for 1 h to obtain a chitosan solution.

[0058] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water, and the mixture was 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 the chitosan solution, and the mixture was stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added, and the mixture was stirred at 300 rpm for 10 min. The mixture was centrifuged and washed with water to obtain the modified porous biochar.

[0059] (3) Modified sepiolite: The sepiolite is acid-washed, water-washed, dried, ground and passed through a 200-mesh sieve.

[0060] Add 0.1 g of sodium carboxymethyl cellulose into 100 mL of water, heat, and stir at 300 rpm to dissolve to obtain a sodium carboxymethyl cellulose solution.

[0061] 5 g of acidified sepiolite was added to 100 mL of sodium carboxymethyl cellulose solution, stirred at 300 rpm for 1 h, centrifuged at 3000 rpm, washed and dried to obtain modified sepiolite.

[0062] (4) Preparation of porous materials:

[0063] Prepare a microbial nutrient solution, wherein the concentration of trypsin is 100 g / L, the concentration of yeast extract is 50 g / L, and the concentration of sodium chloride is 100 g / L;

[0064] Add 1 g of the hydrophobically modified sodium alginate obtained in step (1) to 100 g of the microbial nutrient solution, stir at 300 rpm to dissolve, add 5 g of the modified porous biochar obtained in step (2), 0.5 g of polylactic acid, 0.5 g of the modified sepiolite obtained in step (3), and 0.5 g of urea, and stir the above materials at 300 rpm to form a mixed solution.

[0065] The mixed solution was dripped into a 50 g / L calcium chloride aqueous solution at a dripping rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80° C. to form a porous material.

[0066] The microscopic morphology of the porous material formed in this embodiment is shown in Figure 1 and Figure 2 .

[0067] Example 2

[0068] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0069] 1 g of the porous material prepared in Example 1 was added into 100 mL of a 5% mass concentration silane coupling agent KH-550 aqueous solution, and the mixture was stirred for reaction for 30 min to obtain a modified porous material.

[0070] Example 3

[0071] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0072] 1 g of the porous material prepared in Example 1 was added into 100 mL of 5% mass concentration silane coupling agent KH-570, and the mixture was stirred for reaction for 30 min to obtain a modified porous material.

[0073] Example 4

[0074] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0075] 1 g of the porous material prepared in Example 1 was added into 100 mL of 5% mass concentration silane coupling agent KH-580, and stirred for reaction for 30 min to obtain a modified porous material.

[0076] Example 5

[0077] This embodiment provides a method for preparing a porous material. The specific steps and parameters are the same as those in Embodiment 1, except that step (2) of modifying the biochar with chitosan is not included, and an equal mass of unmodified porous biochar (i.e., porous biochar after pyrolysis treatment) in step (1) is used to replace the active material in step (4).

[0078] Example 6

[0079] The present embodiment provides a method for preparing a porous material, wherein the specific steps and parameters are the same as those of the embodiment 1, except that the reaction system of the chitosan-modified biochar in step (2) does not contain whey protein and emulsifier, i.e., (2) modification of active material: the straw is crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tubular furnace at 600°C for 3 h at a heating rate of 5°C / min in a nitrogen atmosphere to obtain biochar, and the biochar is acid-washed, washed with water, dried, and ground and passed through a 200-mesh sieve to obtain porous biochar;

[0080] 0.5 g of chitosan was added into 25 mL of 1% by volume glacial acetic acid solution and stirred for 1 h to dissolve the chitosan solution.

[0081] 1 g of porous biochar was added to 25 mL of deionized water and stirred for 1 h to prepare a mixed solution, the mixed solution was added dropwise to the chitosan solution, stirred for 1 h, 0.1 mL of glutaraldehyde was added, stirred for 10 min, and the modified porous biochar was obtained by centrifugation and washing.

[0082] Example 7

[0083] This embodiment provides a method for preparing a porous material. The specific steps and parameters are the same as those in Embodiment 1, except that an equal mass of deionized water is used to replace the microbial nutrient solution in step (4).

[0084] Example 8

[0085] This embodiment provides a method for preparing a porous material. The specific steps and parameters are the same as those in Embodiment 1, except that an equal mass of unmodified sepiolite is used to replace the modified sepiolite in step (3).

[0086] Example 9

[0087] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0088] (1) Hydrophobic modification of sodium alginate: 5 g of sodium alginate was dissolved in 100 mL of dimethyl sulfoxide, 2.5 g of sodium periodate was added, and the mixture was stirred at 200 rpm for 5 h at 35 °C in the dark, 0.05 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.05 g of N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 400 rpm for 10 min, 2 g of ethylenediamine was added, the temperature was raised to 150 °C, and the mixture was stirred at 600 rpm for 2 h. The mixture was centrifuged at 5000 rpm for 5 min, washed with water, and dried to obtain hydrophobicized sodium alginate.

[0089] (2) Modification of active materials: Sawdust was crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 400 °C for 6 h with a heating rate of 5 °C / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0090] 0.5 g of chitosan was added into 12.5 mL of 3% by volume glacial acetic acid solution, and the solution was dissolved by stirring at 300 rpm for 1 h to obtain a chitosan solution.

[0091] 0.5 g of whey protein and 0.1 mg of sodium stearate were added to 50 mL of deionized water, and the mixture was stirred at 600 rpm for 1 h to dissolve. Then, 5 g of porous biochar was added and stirred for 1 h to prepare a mixed solution. The mixed solution was added dropwise to the chitosan solution, and the mixture was stirred at 300 rpm for 1 h. 1 mL of glutaric anhydride was added, and the mixture was stirred at 300 rpm for 10 min. The mixture was centrifuged and washed with water to obtain the modified porous biochar.

[0092] (3) Modified attapulgite: The attapulgite was acid-washed, washed with water, dried, ground and passed through a 200-mesh sieve.

[0093] Add 0.5 g of sodium hydroxyethyl cellulose into 100 mL of water, heat, and stir at 300 rpm to dissolve to obtain a sodium hydroxyethyl cellulose solution.

[0094] 5 g of acidified attapulgite was added into 50 mL of sodium hydroxyethyl cellulose solution, stirred at 300 rpm for 1 h, and centrifuged at 3000 rpm for washing and drying to obtain modified attapulgite.

[0095] (4) Preparation of porous materials:

[0096] Prepare a microbial nutrient solution, wherein the concentration of trypsin is 100 g / L, the concentration of yeast extract is 50 g / L, and the concentration of sodium chloride is 100 g / L;

[0097] 5 g of the hydrophobically modified sodium alginate prepared in step (1) was added to 10 g of the microbial nutrient solution, and the solution was dissolved by stirring at 300 rpm. 5 g of the modified porous biochar prepared in step (2), 0.5 g of polyhydroxyalkanoate, 0.5 g of the modified sepiolite prepared in step (3), and 0.5 g of ammonium bicarbonate were added, and the above materials were stirred at 300 rpm to form a mixed solution.

[0098] The mixed solution was dropped into a 10 g / L barium chloride aqueous solution at a dropping rate of 1 mL / min, and stirred at 400 rpm for 1 h at 120° C. to form a porous material.

[0099] 1 g of the porous material was added into 150 mL of 1% mass concentration of silane coupling agent KH570, and the mixture was stirred for reaction for 30 min to obtain a modified porous material.

[0100] Example 10

[0101] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0102] (1) Hydrophobic modification of sodium alginate: 5 g of sodium alginate was dissolved in 1000 mL of anhydrous ethanol, 0.1 g of sodium periodate was added, and the mixture was stirred at 300 rpm for 2 h at 25 °C in the dark, 0.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5 g of N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 300 rpm for 10 min, 0.1 g of ethanolamine was added, the reaction temperature was increased to 100 °C, and the mixture was stirred at 300 rpm for 5 h, then centrifuged at 5000 rpm for 5 min, washed with water, and dried to obtain hydrophobicized sodium alginate.

[0103] (2) Modification of active materials: The fruit shells were crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 800 °C for 2 h with a heating rate of 5 °C / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0104] 1 g of chitosan was added into 100 mL of 2% by volume glacial acetic acid solution, and the solution was dissolved by stirring at 300 rpm for 1 h to obtain a chitosan solution.

[0105] 1 g of whey protein and 0.5 mg of sodium dodecyl sulfate were added to 100 mL of deionized water, and the mixture was 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 the chitosan solution, and the mixture was stirred at 300 rpm for 1 h. 1 mL of succinic anhydride was added, and the mixture was stirred at 300 rpm for 10 min. The mixture was centrifuged and washed with water to obtain the modified porous biochar.

[0106] (3) Modified sepiolite: The illite is acid-washed, water-washed, dried, ground and passed through a 200-mesh sieve.

[0107] Add 1 g of hydroxypropyl cellulose into 100 mL of water, heat, and stir at 200 rpm to dissolve to obtain a hydroxypropyl cellulose solution.

[0108] 5 g of acidified illite was added to 100 mL of hydroxypropyl cellulose solution, stirred at 400 rpm for 1 h, centrifuged at 3000 rpm, washed and dried to obtain modified illite.

[0109] (4) Preparation of porous materials:

[0110] Prepare a microbial nutrient solution, wherein the concentration of trypsin is 100 g / L, the concentration of yeast extract is 50 g / L, and the concentration of sodium chloride is 100 g / L;

[0111] 1 g of the hydrophobically modified sodium alginate obtained in step (1) was added to 100 g of the microbial nutrient solution, and the solution was dissolved by stirring at 300 rpm. 5 g of the modified porous biochar obtained in step (2), 0.5 g of polyethylene terephthalate-1,4-cyclohexane dimethanol ester, 0.5 g of the modified illite obtained in step (3), and 0.5 g of urea were added, and the above materials were stirred at 300 rpm to form a mixed solution.

[0112] The mixed solution was dripped into a 50 g / L magnesium nitrate aqueous solution at a dripping rate of 0.1 mL / min, and stirred at 400 rpm for 3 h at 100° C. to form a porous material.

[0113] 1 g of the porous material was added into 120 mL of 3% mass concentration of silane coupling agent KH570, and the mixture was stirred for reaction for 30 min to obtain a modified porous material.

[0114] Embodiment 11

[0115] This embodiment provides a method for preparing a porous material, and the specific steps and parameters are as follows:

[0116] (1) Hydrophobic modification of sodium alginate: 5 g of sodium alginate was dissolved in 200 mL of isopropanol, 0.1 g of sodium periodate was added, and the mixture was stirred at 600 rpm for 2 h at 25 °C in the dark. 0.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 0.5 g of N-hydroxysuccinimide (NHS) were added, and the mixture was stirred at 200 rpm for 10 min. 2 g of n-hexylamine was added, and the reaction temperature was increased to 100 °C. The mixture was stirred at 400 rpm for 2 h, and then the mixture was centrifuged at 5000 rpm for 5 min, washed with water, and dried to obtain hydrophobicized sodium alginate.

[0117] (2) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 600 °C for 3 h with a heating rate of 5 °C / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0118] 0.5 g of chitosan was added into 25 mL of 1% by volume glacial acetic acid solution, and the solution was dissolved by stirring at 300 rpm for 1 h to obtain a chitosan solution.

[0119] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water, and the mixture was 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 the chitosan solution, and the mixture was stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added, and the mixture was stirred at 300 rpm for 10 min. The mixture was centrifuged and washed with water to obtain the modified porous biochar.

[0120] (3) Modified sepiolite: The sepiolite is acid-washed, water-washed, dried, ground and passed through a 200-mesh sieve.

[0121] Add 0.1 g of sodium carboxymethyl cellulose into 100 mL of water, heat, and stir at 300 rpm to dissolve to obtain a sodium carboxymethyl cellulose solution.

[0122] 5 g of acidified sepiolite was added to 100 mL of sodium carboxymethyl cellulose solution, stirred at 300 rpm for 1 h, centrifuged at 3000 rpm, washed and dried to obtain modified sepiolite.

[0123] (4) Preparation of porous materials:

[0124] Prepare a microbial nutrient solution, wherein the concentration of trypsin is 100 g / L, the concentration of yeast extract is 50 g / L, and the concentration of sodium chloride is 100 g / L;

[0125] Add 1 g of the hydrophobically modified sodium alginate obtained in step (1) to 100 g of the microbial nutrient solution, stir at 300 rpm to dissolve, add 5 g of the modified porous biochar obtained in step (2), 0.5 g of polylactic acid, 0.5 g of the modified sepiolite obtained in step (3), and 0.5 g of urea, and stir the above materials at 300 rpm to form a mixed solution.

[0126] The mixed solution was dropped into a 50 g / L calcium chloride aqueous solution at a dropping rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80° C. to form a porous material.

[0127] Comparative Example

[0128] This comparative example provides a method for preparing a porous material. The specific steps and parameters are the same as those of Example 1, except 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.

[0129] The specific steps are as follows:

[0130] (1) Modification of active materials: The straw was crushed and passed through a 200-mesh sieve, soaked in 2 g / L NaCO3, taken out and dried, and then pyrolyzed in a tube furnace at 600 °C for 3 h with a heating rate of 5 °C / min and a nitrogen atmosphere to obtain biochar. The biochar was acid-washed, washed with water, dried, and ground through a 200-mesh sieve to obtain porous biochar.

[0131] 0.5 g of chitosan was added into 25 mL of 1% by volume glacial acetic acid solution, and the solution was dissolved by stirring at 300 rpm for 1 h to obtain a chitosan solution.

[0132] 0.5 g of whey protein and 0.5 mg of Tween-80 were added to 25 mL of deionized water, and the mixture was 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 the chitosan solution, and the mixture was stirred at 300 rpm for 1 h. 0.1 mL of glutaraldehyde was added, and the mixture was stirred at 300 rpm for 10 min. The mixture was centrifuged and washed with water to obtain the modified porous biochar.

[0133] (2) Modified sepiolite: The sepiolite is acid-washed, water-washed, dried, ground and passed through a 200-mesh sieve.

[0134] Add 0.1 g of sodium carboxymethyl cellulose into 100 mL of water, heat, and stir at 300 rpm to dissolve to obtain a sodium carboxymethyl cellulose solution.

[0135] 5 g of acidified sepiolite was added to 100 mL of sodium carboxymethyl cellulose solution, stirred at 300 rpm for 1 h, centrifuged at 3000 rpm, washed and dried to obtain modified sepiolite.

[0136] (3) Preparation of porous materials:

[0137] Prepare a microbial nutrient solution, wherein the concentration of trypsin is 100 g / L, the concentration of yeast extract is 50 g / L, and the concentration of sodium chloride is 100 g / L;

[0138] Add 1 g of sodium alginate to 100 g of microbial nutrient solution, stir at 300 rpm to dissolve, add 5 g of the modified porous biochar prepared in step (2), 0.5 g of polylactic acid, 0.5 g of the modified sepiolite prepared in step (3), and 0.5 g of urea, and stir the above materials at 300 rpm to form a mixed solution.

[0139] The mixed solution was dropped into a 50 g / L calcium chloride aqueous solution at a dropping rate of 0.5 mL / min, and stirred at 400 rpm for 1 h at 80° C. to form a porous material.

[0140] Application Example 1

[0141] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0142] 20 g of the modified porous material prepared in Example 1 was placed in a 5×5 cm filter bag, placed in a groundwater monitoring well, and taken out after 60 days to detect the microbial community information.

[0143] Application Example 2

[0144] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0145] 20 g of the modified porous material prepared in Example 2 was placed in a 5×5 cm filter bag, placed in a groundwater monitoring well, and taken out after 60 days to detect the microbial community information.

[0146] Application Example 3

[0147] This application example provides a method for detecting groundwater microbial communities. The specific steps and parameters are as follows:

[0148] 20 g of the modified porous material prepared in Example 3 was placed in a 5×5 cm filter bag, placed in a groundwater monitoring well, and taken out after 60 days to detect the microbial community information.

[0149] Experimental Example 1

[0150] 1% (v / v) Pseudomonas nitroreducens seed solution was inoculated into 250 mL of culture medium. The strain was deposited in China General Microbiological Culture Collection Center with the deposit number: CGMCC1.8737.

[0151] 0.5 g of porous material was added to the seed liquid, and the mixture was continuously fixed in a shaker at 200 rpm at 25 °C for 48 h, allowed to stand for 12 h to separate the solid and liquid, and centrifuged at 4000 r / min for 10 min. The supernatant was removed, and physiological saline was added. The mixture was centrifuged at 4000 r / min for 10 min, and the process was repeated twice. The mixture was dried to constant weight, and the adsorption capacity of microorganisms by the porous material was determined based on the weight difference between the porous material and the dried material (see Table 1).

[0152] Wherein, the porous material is the porous material prepared in Examples 1-8 and Comparative Examples.

[0153] Table 1 Adsorption capacity of porous materials on microorganisms

[0154]

[0155] According to the data in Table 1, it can be seen that compared with the comparative example using unmodified sodium alginate as the raw material of the porous material, the porous material prepared by hydrophobically modified sodium alginate in the present invention can increase the adsorption amount of microorganisms. At the same time, compared with Examples 5-8, the porous material microbial adsorption amount prepared by Examples 1-4 of the present invention by modifying the porous biochar, compounding the porous biochar with whey protein, modified sepiolite and adding microbial nutrient solution can reach more than 40 mg / g.

[0156] Experimental Example 2

[0157] 1% (v / v) Pseudomonas nitroreducens seed solution was inoculated into 250 mL of culture medium. The strain was deposited in China General Microbiological Culture Collection Center with the deposit number: CGMCC1.8737.

[0158] 0.5 g of porous material was added to the seed solution, and the solution was fixed in a shaker at 200 rpm at 25 °C for 60 consecutive days. The solution was allowed to stand for 12 h to separate the solid and liquid, and centrifuged at 4000 r / min for 10 min. The supernatant was removed, and physiological saline was added. The solution was centrifuged at 4000 r / min for 10 min, and the process was repeated twice. The solution was dried to a constant weight, and the adsorption capacity of the porous material on microorganisms was determined based on the weight difference between the porous material and the dried weight (see Table 2).

[0159] Wherein, the porous material is the porous material prepared in Examples 1-8 and Comparative Examples.

[0160] Table 2 Adsorption of microorganisms by porous materials

[0161]

[0162] According to the data in Table 2, compared with the comparative example using unmodified sodium alginate as the raw material of the porous material, the porous material prepared by using hydrophobically modified sodium alginate in the present invention can still maintain the structural integrity of the porous material within a treatment time of 60 days, and achieve long-term microbial adsorption, while the porous material prepared by using unmodified sodium alginate in the comparative example gradually dissolves in water in about 20 days, and the microbial adsorption effect is extremely poor.

[0163] Experimental Example 3

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

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

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

[0167] After the adsorption, the filtrate was taken and passed through the membrane. The naphthalene concentration was determined by PT-GC-MS (PT: TEM-Atomx, Agilent Technologies, Inc., USA; GC-MS: Agilent Technologies, Inc., USA), and the determination method was "HJ639-2012 Determination of Volatile Organic Compounds in Water Quality by Purge and Trap / Gas Chromatography-Mass Spectrometry". Tetracycline and patulin were mainly determined by LC-MS (Agilent Technologies, Inc., USA), and 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 Yin Juyi et al. "High Performance Liquid Chromatographic Determination of Patulin Residue in Concentrated Apple Juice." Journal of Analytical Science 23.1 (2007): 3.

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

[0169] Table 3 Adsorption of organic pollutants by porous materials

[0170]

[0171]

[0172] According to Table 3, the present invention can improve the adsorption amount of organic pollutants by using a composite silane coupling agent on the basis of a porous material, wherein the adsorption amount of a certain organic pollutant can be directed by the selection of the silane coupling agent material, which provides convenience for the directional screening of microbial strains for repairing specific organic pollutants.

[0173] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a porous material, characterized in that: The following steps are included: mixing hydrophobically modified sodium alginate, biochar, mineral material, pore former and stabilizer to form a mixed solution; The mixed solution is dropped into a metal salt solution and subjected to heat treatment to obtain a porous material.

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

3. The method for preparing a porous material according to claim 2, characterized in that: The step of oxidizing sodium alginate comprises mixing sodium alginate and an oxidant for reaction in the presence of an organic solvent, wherein the reaction temperature is 25-35° C. and the mixing reaction time is 1-5 hours; and / or, The amidation agent includes at least one of acrylamide, ethylenediamine, ethanolamine and n-hexylamine; and / or, The catalyst comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide; and / or, The oxidized sodium alginate is reacted with an amidation agent in the presence of a catalyst, the reaction temperature is 100-150° C., and the reaction time is 2-5 hours; and / or, The biochar is prepared by reacting porous biochar and chitosan solution in the presence of a cross-linking agent, and the ratio of the porous biochar, chitosan and cross-linking agent is 1:0.1-1:0.1-1, and the unit is g:g:mL.

4. The method for preparing a porous material according to claim 3, characterized in that: The mass ratio of the organic matter of the sodium alginate, the oxidant, the catalyst and the amidation agent is 1-5:0.1-0.5:0.1-1:0.1-2; and / or, The organic solvent comprises at least one of N,N-dimethylformamide, dimethyl sulfoxide and an alcohol solvent; and / or, The oxidizing agent comprises sodium periodate; and / or, The ratio of sodium alginate to organic solvent is 1:20-200, in g:mL; and / or, The cross-linking agent comprises 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, the ratio of chitosan to glacial acetic acid aqueous solution is 1:25-100, the unit is g:mL, and the concentration of glacial acetic acid aqueous solution is 1-3 vol%; and / or, In the biochar preparation step, 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 and separating the solid from the liquid; and / or, The porous biochar is prepared by soaking the biochar in an alkaline solution, drying it, and pyrolyzing it in an inert atmosphere. The pyrolysis temperature is 400-800° C., and the pyrolysis time is 2-6 hours.

5. The method for preparing a porous material according to claim 4, characterized in that: The whey protein aqueous solution further comprises a surfactant, the mass ratio of the whey protein to the surfactant is 1000-5000:1, and the surfactant comprises at least one of 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, expressed in g:mL, and the concentration of the aqueous solution of the cellulose ether compound is 1-5g / 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 former includes at least one of urea, ammonium bicarbonate and ammonium carbonate; and / or, The biochar comprises at least one of straw, wood chips and fruit shells; and / or, The mineral material includes at least one of sepiolite, attapulgite and illite.

6. The method for preparing a porous material according to any one of claims 1 to 5, characterized in that: The mass ratio of the hydrophobically modified sodium alginate, biochar, mineral material, pore former 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° C. and the heat treatment time is 1-3 hours; and / or, The rate of dripping the mixed solution into the metal salt solution is 0.1-1 mL / min; and / or, The metal salt comprises at least one of a calcium salt, a barium salt, a magnesium salt and an iron salt; and / or, The stabilizer includes at least one of polylactic acid, polyhydroxyalkanoate, and polyethylene terephthalate-1,4-cyclohexanedimethanol.

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

8. The method for preparing a porous material according to claim 7, characterized in that: The functional group of the silane coupling agent includes at least one of an amine group, a carboxyl group and a thiol group; 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: The porous material is prepared by the method for preparing the porous material according to any one of claims 1 to 8.

10. Use of the porous material according to claim 9 in groundwater microbial monitoring, microbial screening and organic matter removal.

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