Magnetic super-hydrophobic oil-absorbing porous elastomer and its preparation method and application

Abstract

The present invention relates to the field of oil-water separation technology, and discloses a magnetic super-hydrophobic, oil-absorbing porous elastomer, its preparation method, and application. The preparation method of the magnetic super-hydrophobic, oil-absorbing porous elastomer of the present invention comprises: 1) inoculating metal dissimilatory bacteria into a culture medium impregnated with the porous elastomer for cultivation; 2) adding an iron salt to the culture medium and continuing the cultivation; and 3) carbonizing the porous elastomer after the cultivation in step 2). According to the method of the present invention, the specific surface area and roughness of the porous elastomer are increased, and the magnetic properties of the porous elastomer are effectively enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-water separation, and in particular to a magnetic super-hydrophobic oil-absorbing porous elastomer and a preparation method and application thereof. Background Art

[0002] With the rapid development of society and the economy, the demand for oil products is increasing across all industries. Oil leaks and spills are becoming more frequent, and the amount of oily wastewater treatment caused by production and daily life continues to increase. Various oil removal methods have emerged, such as oil separation, flotation, centrifugation, flocculation, membrane separation, and absorption / adsorption. Each treatment method has its own scope of application and limitations. When responding to sudden oil spills, spraying oil absorbing materials for absorption / adsorption remains the preferred option. However, the development of high-performance, high-oil-holding, low-cost, and environmentally friendly oil absorbing materials remains a challenge.

[0003] Oil-absorbing materials can generally be categorized as oleophilic and hydrophobic, and can be divided into four major groups: carbon-based and its derivatives, granular and powdered materials, resins, sponges, and foam-based materials. Each of these groups has its own advantages and disadvantages. The most prominent form of carbon-based and its derivatives is carbon-based aerogels, which consist of interconnected three-dimensional networks and possess advantages such as low density, high porosity, large specific surface area, good chemical stability, and softness. Their inherent hydrophobicity makes them ideal adsorbents for oil / water separation. Despite their numerous advantages, carbon-based aerogels' poor mechanical strength and high production costs remain limiting their industrial application. Granular and powdered materials, such as calcium carbonate powder, silica-loaded plasma polymers, and porous polysulfone microspheres, are recent conceptual materials. However, these granules and powders are difficult to transfer and recover after use in oil absorption. Therefore, researchers have developed magnetic and recyclable granular and powdered materials. However, this material has two drawbacks in actual production and application: super-hydrophobic and super-oleophilic particles and powders have low oil absorption capacity; and most magnetic hydrophobic and oleophilic particles are easily destroyed in solution, resulting in a decrease in their super-hydrophobicity. While oil-absorbing resins offer good adsorption rates and oil-holding capacity, their high price (often exceeding 100,000 yuan per ton) makes them unaffordable for most companies and restricts their use to specific locations.

[0004] Sponge and foam-based materials are inexpensive and commercially available porous materials with good mechanical strength. They are potential oil-water adsorption and separation material matrices, but they are usually water-wettable, resulting in their lack of selectivity (they can adsorb both water and organic matter such as oils). Their specific surface area is limited, so they usually need to be modified to improve their oleophilicity and hydrophobicity. Modification methods include in-situ growth, dip coating, chemical grafting, carbonization, template method, gas phase polymerization and vapor deposition, but most of these methods are limited to laboratory-scale preparation and do not have the potential for industrialization. In addition, these modification methods usually require a large amount of chemical reagents (such as tetrahydrofuran, toluene, etc.), which cause great harm to the environment. There is an urgent need to find a green modification method. In addition, the effective recovery of oil-absorbing materials can effectively reduce the amount of adsorbent material used and recycle resources, which has strong practical significance. Magnetic recovery is an extremely effective recovery method, but how to improve the magnetic properties of the sponge (i.e., increase the loading capacity of metals such as iron and nickel) is also a problem to be solved.

[0005] CN110743200A discloses a super-hydrophobic and super-oleophilic three-dimensional porous material, its preparation method, and its application. This method utilizes a commercial sponge or other three-dimensional porous material, such as a commercial sponge, to load the polymer after dissolving different types of polymers in a solvent. The preparation method has a certain degree of universality. However, many of the polymer materials described in the patent are difficult to dissolve in the ethanol / water solution described in the patent, ultimately requiring the use of toxic and hazardous organic solvents, which may cause environmental pollution.

[0006] CN111266085A discloses a magnetic oil-absorbing material that can be remotely controlled by a drone and a preparation method thereof. The preparation process is to modify the surface of waste foam with a polymer containing a carbonyl group, and to impregnate Fe 3+ The foam surface is modified, then sealed in a reactor and subjected to a high-temperature carbonization reaction to produce a magnetic oil-absorbing material. However, the material obtained in this invention has a low iron loading, which may result in weak magnetic properties. Furthermore, since this patent still uses a large amount of high-molecular-weight polymer, the preparation cost is relatively high.

[0007] CN110483049A discloses a resilient magnetic carbon foam and its preparation method. The magnetic carbon foam material is prepared from melamine foam through ultrasonic cleaning, soaking in a magnetic metal ion solution, and carbonization and pyrolysis in an argon atmosphere. The resilient magnetic carbon foam is composed of a carbonized porous skeleton of melamine foam, magnetic metal nanoparticles, and carbon nanotubes catalyzed by the magnetic metal nanoparticles. The magnetic metal nanoparticles are coated with the generated carbon nanotubes and evenly distributed on the surface of the melamine foam skeleton. Because the present invention directly carbonizes the melamine foam, the sponge is not pre-modified before carbonization as in CN111266085A. This may result in a smaller specific surface area and insufficient surface roughness of the sponge, which is not conducive to oil adsorption. In addition, this patent also has disadvantages such as a low magnetic material load, which is not conducive to magnetic recovery.

[0008] In summary, the preparation methods of green oil-absorbing materials with high magnetic material loading are still relatively scarce. Summary of the Invention

[0009] The purpose of the present invention is to provide a new magnetic super-hydrophobic oil-absorbing porous elastomer and its preparation method and application. According to the method, a self-assembled biofilm formed by the growth of metal-dissimilar reducing bacteria is attached to the surface of the porous elastomer fiber, and the specific surface area and roughness of the porous elastomer are increased after carbonization. The modification process does not involve toxic or harmful solvents. In addition, in addition to the porous elastomer itself adsorbing iron ions, the metal-dissimilar reducing bacteria attached to the porous elastomer also increase the iron loading capacity of the entire porous material by absorbing / reducing iron ions themselves, thereby effectively improving the magnetic properties of the porous elastomer.

[0010] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a magnetic super-hydrophobic oil-absorbing porous elastomer, wherein the method comprises the following steps:

[0011] 1) inoculating and culturing metal-reducing bacteria in a culture medium in which the porous elastomer is impregnated;

[0012] 2) adding iron salt to the culture medium and continuing the culture;

[0013] 3) Carbonizing the porous elastomer after culture in step 2).

[0014] Preferably, the porous elastomer is a sponge, preferably a melamine sponge and / or a polyurethane sponge.

[0015] Preferably, the volume ratio of the porous elastomer to the culture medium is 1:2-4.

[0016] Preferably, the metal dissimilatory reducing bacteria is selected from one or more of the genera Shewanella and Geobacer.

[0017] Preferably, the culture medium is AB medium or M9 medium.

[0018] Preferably, the culture conditions in step 1) include: anaerobic culture, a culture temperature of 35-37° C., a culture speed of 120-180 rpm, and a culture time of 8-24 h.

[0019] Preferably, the method further comprises the steps of washing and drying the porous elastomer before step 1).

[0020] Preferably, the iron salt is one or more of ferric acetate, ferric chloride and ferric nitrate.

[0021] Preferably, the iron salt is used in the form of a solution.

[0022] Preferably, the concentration of the iron salt solution is 0.5-1 mol / L.

[0023] Preferably, the iron salt is added in 3-6 batches, with the addition interval of each batch of iron salt being 4-8 hours.

[0024] Preferably, the iron salts are added so that the total concentration of the iron salts in the culture medium is 25-75 mM in terms of elemental iron.

[0025] Preferably, the culture conditions in step 2) include: anaerobic culture, a culture temperature of 35-37° C., a culture speed of 120-180 rpm, and a culture time of 8-12 h.

[0026] Preferably, the carbonization treatment conditions include: under the protection of an inert protective gas, heating from room temperature to 300-450° C. at a rate of 2-5° C. / min, and then carbonizing for 2-5 hours.

[0027] Preferably, the method further comprises a step of drying the porous elastomer before the carbonization treatment.

[0028] According to a second aspect of the present invention, there is provided a magnetic super-hydrophobic and oil-absorbing porous elastomer prepared by the method for preparing the magnetic super-hydrophobic and oil-absorbing porous elastomer according to the first aspect of the present invention.

[0029] According to a third aspect of the present invention, there is provided an application of the magnetic super-hydrophobic, oil-absorbing porous elastomer prepared by the preparation method of the magnetic super-hydrophobic, oil-absorbing porous elastomer described in the first aspect of the present invention in the treatment of oily wastewater.

[0030] Through the above technical scheme, the present invention uses non-toxic and harmless metal-reducing bacteria as a biological modifier and a porous elastomer (preferably a sponge) as a carrier. It utilizes the property of metal-reducing bacteria that can absorb and reduce trivalent iron as an electron acceptor, and absorbs / reduces trivalent iron while uniformly growing a biofilm on the porous elastomer (preferably a sponge), and finally carbonizes to form a hydrophobic and lipophilic porous elastomer (preferably a sponge).

[0031] The hydrophobic and oleophilic porous elastomer (preferably a sponge) prepared in this way has the following advantages: first, the self-assembled biofilm formed by the growth of metal-dissimilar reducing bacteria adheres to the surface of the porous elastomer (preferably a sponge) fibers, and after carbonization, the specific surface area and roughness of the porous elastomer (preferably a sponge) are increased, and the modification process does not involve toxic or harmful solvents; second, in addition to the porous elastomer (preferably a sponge) itself adsorbing iron ions, the metal-dissimilar reducing bacteria attached to the porous elastomer (preferably a sponge) absorb / reduce iron ions themselves, which promotes the increase of the iron loading capacity of the entire porous material, effectively improving the magnetic properties of the porous elastomer (preferably a sponge). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 3 is a SEM image of the magnetic super-hydrophobic oil-absorbing porous elastomer prepared in Example 1.

[0033] Figure 2 This is the SEM image of the melamine sponge after direct carbonization (Comparative Example 1).

[0034] Figure 3 This figure shows the sponge prepared in Example 1 adsorbing diesel and then approaching the beaker wall under the action of a magnet.

[0035] Figure 4 This is a diagram showing that a water-blocking air film is formed on the sponge prepared in Example 1 after it is forcibly immersed in water. DETAILED DESCRIPTION

[0036] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0037] According to a first aspect of the present invention, a method for preparing a magnetic super-hydrophobic oil-absorbing porous elastomer is provided, wherein the method comprises the following steps:

[0038] 1) inoculating and culturing metal-reducing bacteria in a culture medium in which the porous elastomer is impregnated;

[0039] 2) adding iron salt to the culture medium and continuing the culture;

[0040] 3) Carbonizing the porous elastomer after culture in step 2).

[0041] According to the present invention, the porous elastic body can be a sponge, preferably a melamine sponge and / or a polyurethane sponge. The use of melamine sponge has the advantage of high mechanical strength.

[0042] According to the present invention, preferably, the volume ratio of the porous elastomer to the culture medium is 1:2-4, for example, it can be 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4, etc.

[0043] According to the present invention, the bacteria used are metal dissimilatory reducing bacteria that have the ability to reduce ferric ions. Such bacteria are, for example, selected from one or more of the genera Shewanella and Geobacter. Specifically, Shewanella oneidensis, Shewanella putrefaciens, Shewanella piezotolerans, Geobacter lovleyi, Geobacter metallireducens, and Geobacter sulfurreducens.

[0044] According to the present invention, the culture medium is not particularly limited and can be any culture medium commonly used in the art for culturing metal dissimilatory reducing bacteria. For example, a mineral-based culture medium such as AB medium or M9 medium can be used, or a culture medium with a relatively clear composition and a mineral-based composition can be selected from the culture media provided on the ATCC website based on the strain number of the bacteria used. For example, the formula per liter of M9 culture medium is as follows: Na2HPO4 6.0g, KH2PO4 3.0g, NaCl 0.5g, NH4Cl 1.0g, 0.01M CaCl2 10.0ml, 1M MgSO4 1.0ml, 20% Glucose 10.0ml, thiamine 1.0mg, amino acid protein hydrolyzate 80.0mg, distilled water 1.0L, adjusted to pH 7.0-7.4.

[0045] According to the present invention, the method further includes removing oxygen from the culture medium by nitrogen bubbling, and sterilizing the culture medium impregnated with the porous elastomer by moist heat sterilization. The sterilization temperature may be, for example, 115° C., and the sterilization time may be, for example, 15-30 minutes.

[0046] According to the present invention, the inoculation volume is not particularly limited and can be a conventional inoculation volume in the art. For example, relative to 1000 mL of culture medium, the inoculation volume of the bacterial solution can be 0.01-0.2 mL, preferably 0.05-0.15 mL. Here, the OD of the bacterial solution is 600 The value may be 0.2-1.2, preferably 0.4-1.0, and particularly preferably 0.7.

[0047] According to the present invention, preferably, the culture conditions in step 1) include: anaerobic culture, a culture temperature of 35-37°C, a culture rotation speed of 120-180 rpm, and a culture time of 8-24 hours. The culture can be carried out in various incubators known in the art and will not be described in detail here.

[0048] According to the present invention, preferably, the method further comprises the steps of washing and drying the porous elastomer before step 1).

[0049] The cleaning may be performed by washing the porous elastomer with ethanol and water for 4-5 times respectively. The drying temperature may be, for example, 50-60° C., and the drying time may be, for example, 4-8 hours.

[0050] According to the present invention, the iron salt is preferably a trivalent iron salt, and more preferably, the iron salt is one or more of ferric acetate, ferric chloride and ferric nitrate.

[0051] In the present invention, the iron salt is preferably used in the form of a solution for ease of operation. When used in the form of a solution, the concentration of the iron salt solution can be 0.5-1 mol / L, preferably 0.6-0.8 mol / L.

[0052] In addition, before use, the iron salt solution is preferably deoxygenated by nitrogen bubbling, and the iron salt solution is passed through a 0.22 μm sterile filter membrane and placed in a sealed sterile container for later use.

[0053] According to the present invention, considering the tolerance of bacteria, preferably, the iron salt is added in batches, preferably, the iron salt is added in 3-6 batches, and the addition interval of each batch of iron salt is 4-8 hours. The amount of iron salt added in batches can be the same or different, but is preferably substantially the same, more preferably the same.

[0054] According to the present invention, preferably, the iron salt is added so that the total concentration of the iron salt in the culture medium is 25-75 mM as elemental iron. For example, the iron salt is added to the culture medium at a total concentration of 50 mM as elemental iron, and when added in four batches, 12.5 mM can be added each time.

[0055] According to the present invention, preferably, the culture conditions in step 2) include: anaerobic culture, a culture temperature of 35-37°C, a culture rotation speed of 120-180 rpm, and a culture time of 8-12 hours. The culture time here refers to the culture time after all iron salts are added. That is, when iron salts are added in batches, iron is added every 4-8 hours, and the culture is continued for 8-12 hours after the last iron addition.

[0056] According to the present invention, preferably, the carbonization treatment conditions include: heating from room temperature to 300-450° C. at a rate of 2-5° C. / min under the protection of an inert protective gas, followed by carbonization for 2-5 hours; more preferably, the carbonization treatment conditions include: heating from room temperature to 350-400° C. at a rate of 3-4° C. / min under the protection of an inert protective gas, followed by carbonization for 3-4 hours. The inert protective gas may be, for example, argon or nitrogen.

[0057] According to the present invention, carbonization treatment has the effects and advantages of increasing the specific surface area and improving the hydrophobicity and lipophilicity of the material.

[0058] According to the present invention, in order to improve the effect of the carbonization treatment, preferably, the method further comprises a step of drying the porous elastomer before the carbonization treatment. Here, the drying temperature may be 50-80° C. and the drying time may be 4-8 hours.

[0059] According to the second aspect of the present invention, there is provided a magnetic super-hydrophobic oil-absorbing porous elastomer prepared by the preparation method of the magnetic super-hydrophobic oil-absorbing porous elastomer according to the first aspect of the present invention.

[0060] According to a third aspect of the present invention, there is provided application of the magnetic super-hydrophobic, oil-absorbing porous elastomer prepared by the preparation method of the magnetic super-hydrophobic, oil-absorbing porous elastomer according to the first aspect of the present invention in the treatment of oily wastewater.

[0061] The present invention will be described in detail below through examples, but the present invention is not limited to the following examples.

[0062] The formula of M9 culture medium per liter is as follows: Na2HPO4 6.0g, KH2PO4 3.0g, NaCl 0.5g, NH4Cl 1.0g, 0.01M CaCl2 10.0ml, 1M MgSO4 1.0ml, 20% Glucose 10.0ml, thiamine 1.0mg, amino acid protein hydrolyzate 80.0mg, distilled water 1.0L, adjust the pH to 7.2.

[0063] Example 1

[0064] 1) Prepare a 5 cm × 5 cm × 5 cm melamine sponge (approximately 2 g) and rinse it five times with ethanol and then water. Dry the sponge in an oven at 60°C for 3 hours. Prepare deoxygenated M9 culture medium and immerse the sponge in this medium at a volume ratio of 1:2. Seal the medium and sterilize it at 115°C for 20 minutes. Separately, prepare a 1 mol / L ferric chloride solution, filter it through a 0.22 μm sterile filter membrane, and place it in a sealed sterile container.

[0065] 2) Take the above culture medium with sponge and inoculate Shewanella (specific strain Shewanella oneidensis MR-1, from the National Bacteria Resource Bank, inoculation volume of 0.1 mL, OD of bacterial solution 600 The culture medium was incubated at a constant temperature of 35°C and a rotation speed of 150 rpm for more than 12 hours. The prepared iron salt was then added to the culture medium in four batches using a sterile syringe, so that the final iron concentration (including divalent and trivalent iron) in the culture medium was 50 mM (12.5 mM per batch). Each batch of iron salt was added 6 hours apart. After the iron salt was completely added, the culture medium was continued for 8 hours.

[0066] 3) After the incubation is completed, the melamine sponge covered with biofilm is taken out and placed in an oven at 60°C for 6 hours for drying; the dried sponge is placed in a tube furnace and, under the protection of nitrogen protective gas, the temperature is raised from room temperature to 350°C at a rate of 3°C / min and carbonized for 3 hours to obtain melamine super-hydrophobic magnetic sponge A1. The SEM image of the obtained melamine super-hydrophobic magnetic sponge A1 is shown in FIG. Figure 1 shown.

[0067] Example 2

[0068] The method of Example 1 was followed, except that in step 2), Geobacter lovleyi (specific strain SZ, from the National Bacteria Resource Bank, inoculated in an amount of 0.08 mL, and the OD of the bacterial solution) was 0. 600 value is 0.7), and a melamine super-hydrophobic magnetic sponge A2 is obtained.

[0069] Example 3

[0070] The method of Example 1 was followed, except that in step 2), Geobacter and Shewanella were inoculated (the specific strain of Shewanella was Shewanellaoneidensis MR-1, obtained from the National Bacteria Resource Bank, the inoculation volume was 0.1 ml, and the OD of the bacterial solution was 0.1. 600The value is 0.8; the specific strain of Geobacter is Geobacterlovleyi Strain SZ, which is from the National Bacteria Resource Bank, the inoculation volume is 0.1 ml, and the OD of the bacterial solution is 600 value is 0.6), and a melamine super-hydrophobic magnetic sponge A3 is obtained.

[0071] Comparative Example 1

[0072] The sponge is carbonized directly after cleaning.

[0073] A 5 cm × 5 cm × 5 cm melamine sponge (mass about 2 g) was taken and repeatedly rinsed with ethanol and water for 5 times. The cleaned sponge was placed in an oven and dried at 60 ° C for 3 hours. The dried sponge was placed in a tube furnace and heated from room temperature to 350 ° C at 3 ° C / min under the protection of nitrogen protective gas and carbonized for 3 hours. The SEM image of the prepared sponge D1 is shown as follows: Figure 2 shown.

[0074] By comparison Figure 1 and Figure 2 It can be seen that after the carbonization of the sponge loaded with microbial growth, the surface of the fiber is loaded with flocs, which increases the roughness.

[0075] Comparative Example 2

[0076] The method of Example 1 was followed, except that no iron salt was added during the culture process.

[0077] 1) Prepare a 5 cm × 5 cm × 5 cm melamine sponge (approximately 2 g) and rinse it five times with ethanol and water. Dry the sponge in an oven at 60°C for 3 hours. Prepare deoxygenated M9 culture medium and immerse the sponge in the medium at a volume ratio of 1:2. Seal the medium and sterilize it at 115°C for 20 minutes.

[0078] 2) Take the above culture medium with sponge and inoculate Shewanella (specific strain Shewanella oneidensis MR-1, from the National Bacteria Resource Bank, inoculation volume of 0.1 mL, OD of bacterial solution 600 The melamine sponge was incubated in a constant temperature incubator at 35°C and 150 rpm for 38 hours. After incubation, the biofilm-covered melamine sponge was removed and dried in an oven at 60°C for 6 hours. The dried sponge was then placed in a tubular furnace and heated from room temperature to 350°C at a rate of 3°C / min under nitrogen atmosphere for carbonization for 3 hours to obtain sponge D2.

[0079] Comparative Example 3

[0080] The method of Example 1 was followed, except that no microbial inoculation was performed.

[0081] 1) Prepare a 5 cm × 5 cm × 5 cm melamine sponge (approximately 2 g) and rinse it five times with ethanol and water. Dry the sponge in an oven at 60°C for 3 hours. Prepare deoxygenated M9 medium and immerse the sponge in a 1:2 sponge to medium ratio by volume. Seal the medium and sterilize it at 115°C for 20 minutes. Prepare a 1 mol / L ferric chloride solution, filter it through a 0.22 μm sterile filter membrane, and place it in a sealed sterile container.

[0082] 2) Place the culture medium with the sponge in a constant temperature incubator at 35°C and 150 rpm. After 12 hours, add the prepared iron salt to the culture medium in four batches using a sterile syringe, so that the final iron concentration (including divalent and trivalent iron) in the culture medium is 50 mM (12.5 mM per batch). Add each batch of iron salt every 6 hours. After the iron salt is completely added, continue incubation for 8 hours.

[0083] 3) After the incubation is completed, the melamine sponge is removed from the oven and dried at 60° C. for 6 hours. The dried sponge is placed in a tubular furnace and heated from room temperature to 350° C. at a rate of 3° C. / min under nitrogen protective gas, and carbonized for 3 hours to obtain sponge D3.

[0084] Test Example 1

[0085] The sponges obtained in Examples 1-3 and Comparative Examples 1-3 were tested for water contact angle, oil contact angle, iron content, ratio of ferric iron to ferrous iron, and diesel adsorption capacity. The results are shown in Table 1. The water and diesel contact angles were measured using a KRUSS contact angle meter; the total iron loading was determined by ICP-MS (detailed method is as follows); the iron valence was determined by XPS; and the diesel adsorption capacity was determined by weighing. A fixed volume of sponge was weighed (m1), and after saturation with diesel adsorption, it was weighed again (m2). Diesel adsorption capacity = (m2 - m1) / m1.

[0086] Iron content determination method: Weigh 1g of carbonized sponge and digest it with a digestion solution consisting of HNO3 solution (70% by weight aqueous solution) + HF acid solution (38.3% by weight aqueous solution) + HClO4 solution (72% by weight aqueous solution). The amount of digestion solution is 10ml (5ml of HNO3 solution, 2mL of HF acid solution, and 3ml of HClO4 solution). The digestion conditions are microwave digestion, the digester power is 800w, and the digestion time is 30min. The iron concentration in the digestion solution is determined by ICP-MS and converted into the mass of iron (m2). The iron content is expressed as m2 / m1.

[0087] Table 1

[0088]

[0089] As shown in Table 1, the contact angles of Examples 1-3 were all higher than those of Comparative Examples 1-3, indicating that the presence of dissimilatory metal-reducing bacteria and iron increased the roughness of the sponge, thereby increasing its hydrophobicity and, consequently, the amount of diesel adsorbed. Comparing Examples 1-3 with Comparative Example 3, the presence of microorganisms in Examples 1-3 effectively increased the iron loading in the sponge. Furthermore, due to the bacterial reduction effect, the ratio of ferric iron to ferrous iron loaded on the sponge was closer to 2:1 (magnetic ferrosoferric oxide), resulting in better magnetic properties.

[0090] Test Example 2

[0091] The magnetic properties of the sponge prepared in Example 1 were verified using a magnet. Figure 3 As shown, the sponge itself has a low density and can float on the water surface. Under the action of the magnet, it gradually approaches the cup wall, indicating that the prepared sponge has very good magnetic properties.

[0092] In addition, if Figure 4 As shown, when the sponge prepared in Example 1 is pressed into water with tweezers, it can be seen that the surface of the sponge is not wetted by water, and a layer of silver bubbles is formed on the surface, indicating that the prepared sponge has very good hydrophobicity.

[0093] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a magnetic super-hydrophobic oil-absorbing porous elastomer, characterized in that: The method comprises the following steps, 1) inoculating and culturing metal-reducing bacteria in a culture medium impregnated with the porous elastomer; 2) adding iron salt to the culture medium and continuing the culture; 3) Carbonizing the porous elastomer after culture in step 2).

2. The method according to claim 1, wherein The porous elastic body is a sponge.

3. The method according to claim 2, wherein: The porous elastic body is melamine sponge and / or polyurethane sponge.

4. The method according to claim 1, wherein The volume ratio of the porous elastomer to the culture medium is 1:2-4.

5. The method according to any one of claims 1 to 4, wherein: The metal dissimilatory reducing bacteria are selected from the genus Shewanella ( Shewanella ) and Geobacter ( Geobacter ) one or more.

6. The method according to any one of claims 1 to 4, wherein: The culture medium is AB culture medium or M9 culture medium.

7. The method according to any one of claims 1 to 4, wherein: The culture conditions in step 1) include: anaerobic culture, a culture temperature of 35-37° C., a culture speed of 120-180 rpm, and a culture time of 8-24 hours.

8. The method according to any one of claims 1 to 4, wherein: The method further comprises the steps of washing and drying the porous elastomer before step 1).

9. The method according to any one of claims 1 to 4, wherein: The iron salt is one or more of ferric acetate, ferric chloride and ferric nitrate.

10. The method according to claim 9, wherein: The iron salt is used in the form of a solution.

11. The method according to claim 10, wherein: The concentration of the iron salt solution is 0.5-1 mol / L.

12. The method according to any one of claims 1 to 4, wherein: The iron salt is added in 3-6 batches, with the addition interval of each batch of iron salt being 4-8 hours.

13. The method according to any one of claims 1 to 4, wherein: The iron salts are added so that the total concentration of the iron salts in the culture medium is 25-75 mM in terms of elemental iron.

14. The method according to any one of claims 1 to 4, wherein: The culture conditions in step 2) include: anaerobic culture, a culture temperature of 35-37° C., a culture speed of 120-180 rpm, and a culture time of 8-12 hours.

15. The method according to any one of claims 1 to 4, wherein: The carbonization treatment conditions include: under the protection of an inert protective gas, heating from room temperature to 300-450° C. at a rate of 2-5° C. / min, and then carbonizing for 2-5 hours.

16. The method according to any one of claims 1 to 4, wherein: The method further comprises the step of drying the porous elastomer before the carbonization treatment.

17. The magnetic super-hydrophobic and oil-absorbing porous elastomer prepared by the preparation method of the magnetic super-hydrophobic and oil-absorbing porous elastomer according to any one of claims 1 to 16.

18. Use of the magnetic super-hydrophobic, oil-absorbing porous elastomer prepared by the preparation method of the magnetic super-hydrophobic, oil-absorbing porous elastomer according to any one of claims 1 to 16 in the treatment of oily wastewater.

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