Modified rubber particles based on microorganism induced calcium carbonate deposition, preparation method thereof and rubber cement-based material
By using microbial-induced calcium carbonate deposition technology to generate calcium carbonate crystals on the surface of rubber particles, the problem of poor interfacial bonding performance of rubber cement-based materials is solved, and the mechanical properties of rubber cement-based materials are significantly improved.
Patent Information
- Application Number
- CN202512060636.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-06
AI Technical Summary
The poor interfacial bonding performance between existing rubber particles and cement-based materials leads to a decline in the mechanical properties of rubber cement-based materials. Traditional modification methods pose environmental risks or have unsatisfactory modification effects.
Microbial-induced calcium carbonate deposition technology is used to generate calcium carbonate crystals that cover the surface of rubber particles through surface hydrophilic pretreatment and mineralizing microbial cultivation, thereby improving their mechanical interlocking force with the cement matrix.
It significantly increases the amount of calcium carbonate crystals generated on the surface of rubber particles, improves the hydrophilicity and mechanical interlocking force of rubber particles, and increases the 28-day compressive strength of rubber cement-based materials by 20-40%.
Smart Images
Figure CN121609538A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, and in particular to a modified rubber particle based on microbial-induced calcium carbonate deposition, its preparation method, and a rubber cement-based material. Background Technology
[0002] Processing waste tires into rubber granules and incorporating them into cement-based materials can effectively improve the toughness, impact resistance, and durability of the materials, giving rubber-cement-based materials good application potential in road engineering and construction. However, the surface of rubber granules is hydrophobic, resulting in poor adhesion between the granules and the cement matrix and a weak interfacial transition zone. This leads to a significant decrease in the mechanical properties of rubber-cement-based materials, limiting their engineering application. Therefore, numerous studies have focused on improving the interfacial adhesion between rubber granules and cement-based materials to enhance mechanical properties. The main approaches include surface modification of rubber granules and the incorporation of functional admixtures. However, existing methods still have significant limitations: physical pretreatment is difficult to change the hydrophobic nature of rubber, resulting in limited modification effects; chemical pretreatment often involves harmful reagents, posing environmental risks, and the treated surface-active substances may age and degrade over time, leading to deterioration of interfacial properties; directly adding admixtures can easily reduce the fluidity of the mixture, introduce internal defects, and fail to fundamentally solve the problem of the weak rubber-cement interfacial transition zone.
[0003] Microbial-induced calcium carbonate deposition technology utilizes the metabolism of specific mineralizing microorganisms to induce the formation of calcium carbonate crystals in the presence of suitable substrates. These calcium carbonate crystals exhibit good compatibility with cement-based materials, and previous studies have attempted to use them for the modification of rubber granules to improve the strength of rubber-cement composites. However, due to the strong hydrophobicity of rubber granule surfaces, traditional soaking methods struggle to effectively adsorb microorganisms onto the surface, resulting in limited calcium carbonate formation and unsatisfactory modification effects.
[0004] Therefore, it is of great significance to develop a green, efficient method for preparing modified rubber particles that can comprehensively improve the surface properties of rubber and significantly enhance the mechanical properties of rubber cementitious materials. Summary of the Invention
[0005] In view of this, the present invention provides modified rubber particles based on microbial-induced calcium carbonate deposition, a method for preparing the same, and a rubber cement-based material, to solve the problem of unsatisfactory modification effects of existing rubber modification methods.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing modified rubber particles based on microbial-induced calcium carbonate deposition, comprising the following steps: 1) The rubber granules are subjected to surface hydrophilic pretreatment to obtain pretreated rubber granules; 2) The pretreated rubber particles are mixed with the mineralizing microbial solution in the early stage of stable growth and cultured to obtain rubber particles adsorbed with mineralizing microorganisms. 3) Mix urea aqueous solution and calcium acetate aqueous solution to obtain a cementing solution. Mix rubber particles adsorbed with mineralizing microorganisms with the cementing solution and carry out a deposition reaction to obtain modified rubber particles based on microbial-induced calcium carbonate deposition.
[0007] Preferably, the solvent for the surface hydrophilic pretreatment in step 1) includes NaOH solution and / or Ca(OH)2 solution; the mass-to-volume ratio of the rubber particles to the solvent is 1 g: 2~5 mL; and the molar concentration of the solvent is 1~5 mol / L.
[0008] Preferably, the surface hydrophilic pretreatment time in step 1) is 24~48 h.
[0009] Preferably, the mineralizing microorganism in step 2) is *Bacillus pasteurellii*; the concentration of the mineralizing microorganism in the bacterial solution is 1 × 10⁻⁶. 7 ~9×10 9 cells / mL.
[0010] Preferably, the mass-to-volume ratio of the pretreated rubber particles to the mineralized microbial solution in step 2) is 1 g: 3~6 mL.
[0011] Preferably, the culture temperature in step 2) is 30°C, the rotation speed is 220 r / min, and the time is 12 h.
[0012] Preferably, in step 3), the volume ratio of the urea aqueous solution and the calcium acetate aqueous solution is 1:1; the molar concentration of the urea aqueous solution is 0.5~1.5 mol / L; and the molar concentration of the calcium acetate aqueous solution is 0.5~1.5 mol / L.
[0013] Preferably, the volume ratio of the rubber particles adsorbed with mineralizing microorganisms to the cementing solution in step 3) is 1:1~3.
[0014] Preferably, the deposition reaction time in step 3) is 24 to 72 hours.
[0015] The present invention also provides modified rubber particles based on microbial-induced calcium carbonate deposition prepared by the above preparation method.
[0016] The present invention also provides a rubber cement-based material comprising the following components in parts by weight: The mixture comprises 50-200 parts of modified rubber particles, 450-800 parts of cement, 1000-1500 parts of sand, and 270-330 parts of water; the modified rubber particles are modified rubber particles based on microbial-induced calcium carbonate deposition prepared by the above preparation method.
[0017] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: The method for preparing modified rubber particles based on microbial-induced calcium carbonate deposition described in this invention can significantly increase the adsorption capacity of bacteria on the surface of rubber particles, thereby increasing the amount of calcium carbonate crystals generated on the surface of the rubber particles. This successfully yields modified rubber particles with a surface covered by a layer of calcium carbonate crystals, exhibiting high surface roughness, a small water contact angle (60~90°), good hydrophilicity, and strong mechanical bonding with the cement matrix. Furthermore, the modified rubber particles prepared using this method can increase the 28-day compressive strength of rubber cement-based materials by 20~40%. In other words, the preparation method described in this invention not only comprehensively improves the surface properties of rubber particles but also significantly enhances the mechanical properties of rubber cement-based materials, demonstrating a very broad application prospect. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0019] Figure 1 This is a SEM image of the unmodified rubber particles in Comparative Example 1 at a magnification of 500. Figure 2 The image shows the modified rubber particles based on microbial-induced calcium carbonate deposition prepared in Example 1 at a magnification of 500. Figure 3 SEM image of the rubber particles adsorbed with mineralized microorganisms prepared in Comparative Example 2 at a magnification of 2000. Figure 4 SEM image of the rubber particles adsorbed with mineralizing microorganisms prepared in Example 1 at a magnification of 2000. Figure 5 The image shows a comparison of the water contact angles between the modified rubber particles based on microbial-induced calcium carbonate deposition prepared in Example 1 and the unmodified rubber particles in Comparative Example 1. Figure 6 The compressive strength diagrams are shown for the rubber cement-based materials prepared in Example 1 and Comparative Example 1. Detailed Implementation
[0020] This invention provides a method for preparing modified rubber particles based on microbial-induced calcium carbonate deposition, comprising the following steps: 1) The rubber granules are subjected to surface hydrophilic pretreatment to obtain pretreated rubber granules; 2) The pretreated rubber particles are mixed with the mineralizing microbial solution in the early stage of stable growth and cultured to obtain rubber particles adsorbed with mineralizing microorganisms. 3) Mix urea aqueous solution and calcium acetate aqueous solution to obtain a cementing solution. Mix rubber particles adsorbed with mineralizing microorganisms with the cementing solution and carry out a deposition reaction to obtain modified rubber particles based on microbial-induced calcium carbonate deposition.
[0021] In this invention, the solvent for the surface hydrophilic pretreatment in step 1) preferably includes NaOH solution and / or Ca(OH)2 solution; the mass-to-volume ratio of the rubber particles to the solvent is 1 g: 2~5 mL, preferably 1 g: 2.2~4.8 mL, more preferably 1 g: 2.5~4.5 mL, and more preferably 2 g: 3~4 mL; the molar concentration of the solvent is 1~5 mol / L, preferably 2~4 mol / L, and more preferably 3 mol / L.
[0022] In this invention, the surface hydrophilic pretreatment time in step 1) is 24~48 h, preferably 25~45 h, more preferably 28~40 h, and more preferably 30~35 h; the surface hydrophilic pretreatment is used to remove hydrophobic substances from the surface of rubber particles and improve the hydrophilicity of the surface of rubber particles.
[0023] In this invention, the surface hydrophilic pretreatment described in step 1) is preferably followed by a water washing operation; the number of water washing operations is preferably 1 to 3 times, and more preferably 3 times.
[0024] In this invention, the mineralizing microorganisms mentioned in step 2) are preferably Bacillus pasteurellii (ATCC11859); the concentration of the mineralizing microorganisms in the bacterial solution is 1×10⁻⁶. 7 ~9×10 9 cells / mL, preferably 5 × 10⁻⁶ 7 ~5×10 9 cells / mL, more preferably 1×10⁻⁶ 8 ~9×10 8 cells / mL.
[0025] In this invention, the mass-to-volume ratio of the pretreated rubber particles to the mineralized microbial solution in step 2) is 1 g: 3~6 mL, preferably 1 g: 3.2~5.5 mL, more preferably 1 g: 3.5~5 mL, and even more preferably 1 g: 4~4.5 mL.
[0026] In this invention, the culture temperature in step 2) is preferably 30°C; the culture rotation speed is preferably 220 r / min; the culture time is preferably 12 h; during the culture process, bacteria grow and reproduce on the surface of rubber particles due to their own metabolic processes and environmental adaptability, thus realizing the adsorption of mineralizing microorganisms on the surface of rubber particles.
[0027] In this invention, the volume ratio of the urea aqueous solution and the calcium acetate aqueous solution in step 3) is preferably 1:1; the molar concentration of the urea aqueous solution is 0.5~1.5 mol / L, preferably 0.8~1.2 mol / L, and more preferably 1 mol / L; the molar concentration of the calcium acetate aqueous solution is 0.5~1.5 mol / L, preferably 0.8~1.2 mol / L, and more preferably 1 mol / L.
[0028] In this invention, the volume ratio of the rubber particles adsorbed with mineralizing microorganisms to the cementing solution in step 3) is 1:1 to 3, preferably one of 1:1, 1:1.5, 1:2, 1:2.5, and 1:3.
[0029] In this invention, the deposition reaction time in step 3) is 24-72 h, preferably 25-70 h, more preferably 30-50 h, and more preferably 35-40 h; during the deposition reaction, the mineralizing microorganisms adsorbed on the surface of the rubber particles use the cementing solution to carry out a microbial-induced calcium carbonate deposition reaction to generate calcium carbonate crystals that coat the rubber particles.
[0030] In this invention, after the deposition reaction described in step 3), it is preferable to repeat step 3) 1 to 5 times, more preferably 2 to 4 times, and even more preferably 3 times, to obtain a calcium carbonate layer with a thickness of 25 to 500 μm; the thickness of the calcium carbonate layer is preferably 30 to 450 μm, and more preferably 300 to 400 μm.
[0031] The present invention also provides modified rubber particles based on microbial-induced calcium carbonate deposition prepared by the above preparation method.
[0032] The present invention also provides a rubber cement-based material, preferably comprising the following components in parts by weight: 50-200 parts modified rubber particles, 450-800 parts cement, 1000-1500 parts sand, and 270-330 parts water; more preferably comprising the following components in parts by weight: 60-150 parts modified rubber particles, 500-600 parts cement, 1200-1300 parts sand, and 272-300 parts water; more preferably comprising the following components in parts by weight: 61.97 parts modified rubber particles, 548.95 parts cement, 1235.13 parts sand, and 274.47 parts water.
[0033] The modified rubber particles are modified rubber particles based on microbial-induced calcium carbonate deposition prepared by the above preparation method.
[0034] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0035] Example 1
[0036] Preparation of modified rubber particles based on microbial-induced calcium carbonate deposition: 1) Rubber granules (particle size 1~3 mm, apparent density 1119 kg / m³) 3 The rubber particles were soaked in NaOH solution (molar concentration of 1 mol / L), where the mass-volume ratio of rubber particles to NaOH solution was 2 g: 5 mL. After soaking for 24 h, the rubber particles were filtered out, rinsed three times with deionized water, and dried to obtain pretreated rubber particles. 2) *Pasteurella multocida* ATCC11859, frozen at -80°C, was aseptically inoculated into 5 mL of sterile liquid YE medium (20 g / L yeast extract (OXOID brand LP0021B), 10 g / L ammonium sulfate, and 17.5 g / L Tris reagent). The medium was then pre-cultured at 30°C and 220 r / min for 24 h until the liquid YE medium became noticeably turbid, yielding the pre-cultured bacterial solution. This pre-cultured bacterial solution was then inoculated into 500 mL of liquid YE medium (20 g / L yeast extract (OXOID brand LP0021B), 10 g / L ammonium sulfate, and 17.5 g / L Tris reagent) at a volume ratio of 1:100 with the liquid YE medium. The medium was then expanded and cultured for 24 h in a shaker at 30°C and 220 r / min. h, allowing the bacteria to reach the initial stable growth stage, yielding a bacterial solution with an OD600 value of 3.1, urease activity of 20 mmol urea / min, and a concentration of mineralizing microorganisms of 4 × 10⁻⁶. 8cells / mL; 1 g of the pretreated rubber particles obtained in step 1) were sterilized in an autoclave at 121°C for 20 min. After returning to room temperature, they were mixed with 5 mL of the above bacterial solution under aseptic conditions. Then, they were placed in a shaker at 30°C and 220 r / min for 12 h and filtered to obtain rubber particles adsorbed with mineralized microorganisms. 3) Mix urea aqueous solution (molar concentration of 1 mol / L) and calcium acetate aqueous solution (molar concentration of 1 mol / L) at a volume ratio of 1:1 to obtain a cementing solution. Then, mix the rubber particles with mineralizing microorganisms obtained in step 2) with the cementing solution at a volume ratio of 1:1 and carry out a deposition reaction for 24 h. Filter and repeat the above deposition reaction process 3 times. Finally, soak in deionized water to remove loose attached crystals, and air dry to obtain modified rubber particles with a calcium carbonate layer thickness of 395 μm based on microbial-induced calcium carbonate deposition.
[0037] Preparation of rubber cement-based materials: The modified rubber particles based on microbial-induced calcium carbonate deposition (61.97 parts), cement (548.95 parts), sand (1235.13 parts), and water (274.47 parts) were mixed to obtain a rubber cement-based material (denoted as mineralized modified rubber cement mortar).
[0038] Example 2
[0039] Preparation of modified rubber particles based on microbial-induced calcium carbonate deposition: 1) Rubber granules (particle size 1~3 mm, apparent density 1119 kg / m³) 3 The rubber particles were soaked in NaOH solution (molar concentration of 3 mol / L), where the mass-volume ratio of rubber particles to NaOH solution was 1 g: 2 mL. After soaking for 48 h, the rubber particles were filtered out, rinsed three times with deionized water, and dried to obtain pretreated rubber particles. 2) *Pasteurella multocida* ATCC11859, frozen at -80°C, was aseptically inoculated into 5 mL of sterile liquid YE medium (yeast extract (OXOID brand LP0021B) 20 g / L, ammonium sulfate 10 g / L, and Tris reagent 17.5 g / L). The medium was then pre-cultured at 30°C and 220 r / min for 24 h until significant turbidity appeared, yielding the pre-cultured bacterial solution. This pre-cultured bacterial solution was then inoculated into 500 mL of liquid YE medium (yeast extract (OXOID brand LP0021B) 20 g / L, ammonium sulfate 10 g / L, and Tris reagent 17.5 g / L) at a volume ratio of 1:100 with the liquid YE medium. The medium was then further cultured at 30°C and 220 r / min for 24 h to allow the bacteria to reach early stable growth, yielding the bacterial solution. The OD of the bacterial solution at this stage was... 600 The value was 3.1, the urease activity was 20 mmol urea / min, and the concentration of mineralizing microorganisms in the bacterial solution was 4 × 10⁻⁶. 8 cells / mL; 1 g of the pretreated rubber particles obtained in step 1) were sterilized in an autoclave at 121°C for 20 min. After returning to room temperature, they were mixed with 5 mL of the above bacterial solution under aseptic conditions. Then, they were placed in a shaker at 30°C and 220 r / min for 12 h and filtered to obtain rubber particles adsorbed with mineralized microorganisms. 3) Mix urea aqueous solution (molar concentration of 1 mol / L) and calcium acetate aqueous solution (molar concentration of 1 mol / L) at a volume ratio of 1:1 to obtain a cementing solution. Then, mix the rubber particles with mineralizing microorganisms obtained in step 2) with the cementing solution at a volume ratio of 1:1 and carry out a deposition reaction for 48 h. After filtration, repeat the above deposition reaction process twice. Finally, soak in deionized water to remove loose attached crystals, and air dry to obtain modified rubber particles with a calcium carbonate layer thickness of 265 μm based on microbial-induced calcium carbonate deposition.
[0040] Preparation of rubber cement-based materials: The modified rubber particles based on microbial-induced calcium carbonate deposition (65.09 parts), cement (548.95 parts), sand (1173.37 parts), and water (274.47 parts) were mixed to obtain a rubber cement-based material.
[0041] Example 3
[0042] Preparation of modified rubber particles based on microbial-induced calcium carbonate deposition: 1) Rubber granules (particle size 1~3 mm, apparent density 1119 kg / m³) 3The rubber particles were soaked in Ca(OH)2 solution (molar concentration of 5 mol / L), where the mass-volume ratio of rubber particles to Ca(OH)2 solution was 1 g: 5 mL. After soaking for 48 h, the rubber particles were filtered out, rinsed three times with deionized water, and dried to obtain pretreated rubber particles. 2) *Pasteurella multocida* ATCC11859, frozen at -80°C, was aseptically inoculated into 5 mL of sterile liquid YE medium (yeast extract (OXOID brand LP0021B) 20 g / L, ammonium sulfate 10 g / L, and Tris reagent 17.5 g / L). The medium was then pre-cultured at 30°C and 220 r / min for 24 h until significant turbidity appeared, yielding the pre-cultured bacterial solution. This pre-cultured bacterial solution was then inoculated into 500 mL of liquid YE medium (yeast extract (OXOID brand LP0021B) 20 g / L, ammonium sulfate 10 g / L, and Tris reagent 17.5 g / L) at a volume ratio of 1:100 with the liquid YE medium. The medium was then further cultured at 30°C and 220 r / min for 24 h to allow the bacteria to reach early stable growth, yielding the bacterial solution. The OD of the bacterial solution at this stage was... 600 The value was 3.1, the urease activity was 20 mmol urea / min, and the concentration of mineralizing microorganisms in the bacterial solution was 4 × 10⁻⁶. 8 cells / mL; 1 g of the pretreated rubber particles obtained in step 1) were sterilized in an autoclave at 121°C for 20 min. After returning to room temperature, they were mixed with 6 mL of the above bacterial solution under aseptic conditions. Then, they were placed in a shaker at 30°C and 220 r / min for 12 h and filtered to obtain rubber particles adsorbed with mineralized microorganisms. 3) A urea aqueous solution (molar concentration of 0.5 mol / L) and a calcium acetate aqueous solution (molar concentration of 0.5 mol / L) were mixed at a volume ratio of 1:1 to obtain a cementing solution. Then, the rubber particles with mineralizing microorganisms adsorbed in step 2) were mixed with the cementing solution at a volume ratio of 1:3 and subjected to a deposition reaction for 72 h. The mixture was filtered, and the deposition reaction process was repeated 3 times. Finally, the loosely attached crystals were removed by soaking in deionized water, and the mixture was dried to obtain modified rubber particles with a calcium carbonate layer thickness of 308 μm based on microbial-induced calcium carbonate deposition.
[0043] Preparation of rubber cement-based materials: The modified rubber particles based on microbial-induced calcium carbonate deposition (58.87 parts), cement (548.95 parts), sand (1296.89 parts), and water (274.47 parts) were mixed to obtain a rubber cement-based material.
[0044] Comparative Example 1
[0045] The only difference between Comparative Example 1 and Example 1 is that the modified rubber particles based on microbial-induced calcium carbonate deposition are replaced with unmodified rubber particles, while other conditions remain unchanged, resulting in a rubber cement-based material (denoted as unmodified rubber cement mortar).
[0046] Comparative Example 2
[0047] The only difference between Comparative Example 2 and Example 1 is that the modified rubber particles were prepared by the traditional soaking method. The specific preparation method of the modified rubber particles by the traditional soaking method is as follows: the rubber particles are directly placed in the bacterial solution (same as in Example 1) for soaking treatment, without cultivation and immobilization under suitable environmental conditions, to obtain rubber particles adsorbed with mineralized microorganisms.
[0048] The surfaces of the modified rubber particles based on microbial-induced calcium carbonate deposition prepared in Example 1 and the unmodified rubber particles in Comparative Example 1 were characterized, and the results are as follows: Figures 1-2 As shown, where, Figure 1 This is a SEM image of the unmodified rubber particles in Comparative Example 1 at a magnification of 500. Figure 2 This is a SEM image of the modified rubber particles based on microbial-induced calcium carbonate deposition prepared in Example 1 at a magnification of 500. Figures 1-2 As can be seen, after microbial mineralization modification of rubber particles, a dense calcium carbonate layer is generated on the surface of the rubber particles. The calcium carbonate crystal coating significantly increases the surface roughness of the rubber particles and enhances the mechanical interlocking force with the cement matrix. That is, compared with the unmodified rubber particles, the performance of the modified rubber particles is significantly improved.
[0049] The surfaces of the rubber particles adsorbed with mineralizing microorganisms prepared in Example 1 and the rubber particles adsorbed with mineralizing microorganisms prepared in Comparative Example 2 were characterized, and the results are as follows: Figures 3-4 As shown, where, Figure 3 This is a SEM image of the rubber particles with adsorbed mineralizing microorganisms prepared in Comparative Example 2 at a magnification of 2000. Figure 4 This is a SEM image of the rubber particles adsorbed with mineralizing microorganisms prepared in Example 1 at a magnification of 2000. Figures 3-4 As can be seen, compared with the traditional soaking method, the rubber particles modified by the preparation method described in this invention have more mineralized bacteria adsorbed on their surface.
[0050] The water contact angles of the modified rubber particles based on microbial-induced calcium carbonate deposition prepared in Example 1 (denoted as modified) and the unmodified rubber particles in Comparative Example 1 (denoted as unmodified) were measured, and the results are as follows: Figure 5 As shown, from Figure 5As can be seen, the water contact angle of the unmodified rubber particles is 128°, while after microbial mineralization modification, the water contact angle of the rubber particles is reduced to 81°, indicating that the hydrophilicity of the modified rubber particles prepared by the preparation method described in this invention is significantly enhanced.
[0051] The compressive strength of the rubber cementitious materials prepared in Example 1 and Comparative Example 1 was tested according to the "Test Procedure for Hydraulic Concrete" (DL / T 5150-2017). The test results are as follows. Figure 6 As shown, from Figure 6 As can be seen from the data, compared with Comparative Example 1, the 28-day compressive strength of the rubber cement-based material prepared using modified rubber particles based on microbial-induced calcium carbonate deposition increased by 32%, which shows that the method described in this invention can effectively improve the mechanical properties of rubber cement-based materials.
[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing modified rubber particles based on microbial induced calcium carbonate deposition, characterized in that, The method comprises the following steps: 1) performing surface hydrophilic pretreatment on rubber particles to obtain pretreated rubber particles; 2) mixing the pretreated rubber particles with a microbial solution of a mineralization microorganism in a stable growth initial stage, and performing culture to obtain rubber particles adsorbed with the mineralization microorganism; 3) mixing a urea aqueous solution and a calcium acetate aqueous solution to obtain a cementation solution, mixing the rubber particles adsorbed with the mineralization microorganism with the cementation solution, and performing a deposition reaction to obtain modified rubber particles based on microbial induction of calcium carbonate deposition.
2. The method for preparing modified rubber particles based on microbial-induced calcium carbonate precipitation according to claim 1, characterized in that, The solvent for the surface hydrophilic pretreatment in step 1) comprises a NaOH solution and / or a Ca(OH)2 solution; The mass-volume ratio of the rubber particles to the solvent is 1 g:2-5 mL; the molar concentration of the solvent is 1-5 mol / L; The time for the surface hydrophilic pretreatment in step 1) is 24-48 h.
3. The method of claim 2, wherein the modified rubber particles are prepared by the method comprising: a) providing a rubber particle; b) providing a microorganism; c) providing a calcium carbonate inducing agent; d) providing a culture medium; e) mixing the rubber particle, the microorganism, the calcium carbonate inducing agent, and the culture medium; and f) incubating the mixture of step e) to produce the modified rubber particle. The mineralization microorganism in step 2) is Bacillus pasteurii; The concentration of the mineralized microorganism in the mineralized microorganism bacterial solution is 1 x 10 7 9 x 10 9 cells / mL.
4. The method for preparing modified rubber particles based on microbial-induced calcium carbonate deposition according to any one of claims 1 to 3, characterized in that, The mass-volume ratio of the pretreated rubber particles to the microbial solution in step 2) is 1 g:3-6 mL.
5. The method for preparing modified rubber particles based on microbial-induced calcium carbonate precipitation according to claim 4, characterized in that, The culture in step 2) is performed at a temperature of 30°C, a rotation speed of 220 r / min, and for a time of 12 h.
6. The method for preparing modified rubber particles based on microbial-induced calcium carbonate precipitation according to claim 5, characterized in that, The volume ratio of the urea aqueous solution to the calcium acetate aqueous solution in step 3) is 1:1; The molar concentration of the urea aqueous solution is 0.5-1.5 mol / L; the molar concentration of the calcium acetate aqueous solution is 0.5-1.5 mol / L.
7. The method of claim 6, wherein the modified rubber particles are prepared by a microbial-induced carbonate precipitation process. The volume ratio of the rubber particles adsorbed with the mineralization microorganism to the cementation solution in step 3) is 1:1-3.
8. The method for preparing modified rubber particles based on microbial-induced calcium carbonate precipitation according to claim 7, characterized in that, The time for the deposition reaction in step 3) is 24-72 h.
9. Modified rubber particles based on microbial induction of calcium carbonate deposition prepared by the preparation method in any one of claims 1-8.
10. A rubber cementitious material, characterized in that, The components comprise the following mass fractions: modified rubber particles 50-200 parts, cement 450-800 parts, sand 1000-1500 parts, and water 270-330 parts; The modified rubber particles are the modified rubber particles based on microbial induction of calcium carbonate deposition in claim 9.