Porous calcium carbonate passivation material with urease activity, and preparation method and application thereof

Abstract

This invention belongs to the field of environmental engineering materials, and specifically discloses a method for preparing a heavy metal passivation material, as well as a porous bio-calcium carbonate passivation material with urease activity obtained therefrom. Based on specific components, this passivation material not only exhibits the heavy metal adsorption properties of porous bio-calcium carbonate, but also maintains urease activity even in environments with extremely high heavy metal concentrations, continuously exerting a biomineralization effect on residual heavy metals. It demonstrates a dual passivation effect of adsorption and mineralization in heavy metal remediation. Its resistance to heavy metal toxicity is significantly improved, overcoming the limitations of traditional MIP technology in restricting heavy metal concentrations, and it possesses extremely high heavy metal adsorption capacity, far exceeding the average level. This passivation material can be applied to heavy metal remediation, and secondary pollution of heavy metals can be prevented by adding an additional calcium source after passivation. The preparation method is simple, controllable, inexpensive, safe, and pollution-free, easy to industrialize, and has great potential for promotion and application value.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering materials. Specifically, it relates to a method for preparing a heavy metal passivation material, a porous bio-calcium carbonate passivation material with urease activity obtained by the method, and its application in environmental engineering, especially in heavy metal remediation. Background Technology

[0002] Currently, with the rapid development of industrialization and urbanization, heavy metal pollution has become one of the most important environmental problems that humanity needs to address. Because heavy metals can persist in the environment, their chronic toxicity, non-biodegradability, and bioaccumulation in the food chain can cause permanent damage to multiple organs, making them extremely harmful environmental pollutants. Among them, cadmium, lead, nickel, copper, and zinc pollution have received particular attention.

[0003] To date, numerous remediation materials and methods have emerged for heavy metal pollution, but most suffer from high costs, incomplete removal, low recyclability, complex operation, and long remediation times. Currently, passivation technology is a feasible and effective remediation technique for heavy metal pollution, and it better aligns with my country's current environmental protection development level and national conditions.

[0004] Passivation refers to the process of treating heavy metals to convert them into an inactive, passive state, thereby effectively reducing their toxicity to organisms in water and soil. Traditional passivation technologies for heavy metal pollution mainly include pH adjustment, mineralization, adsorption, and ion exchange.

[0005] A novel microbial-induced carbonate deposition technology has emerged. This technology utilizes urease produced by urease bacteria to decompose carbonate ions. In the presence of metal ions such as calcium and cadmium ions, these carbonate ions react with carbonate ions to form a more stable carbonate form, thereby effectively reducing heavy metal toxicity. In water pollution caused by heavy metals, urease bacteria with a certain activity react with urea to generate carbonate and ammonium ions, which then precipitate out of the solution. In soil pollution caused by heavy metals, the reaction of urease bacteria with urea generates carbonate and ammonium ions, which exist in a more stable carbonate form. This process accelerates the transformation of heavy metals into more stable forms, reduces the mobility of heavy metals in the soil, and consequently reduces their toxicity to plants and microorganisms.

[0006] However, current research on the above carbonate deposition techniques has a drawback: they cannot be applied to environments with high concentrations of heavy metals. This is because high concentrations of heavy metals can inactivate urease-producing bacteria, preventing the production of urease and thus the decomposition of urea into carbonate ions, as seen in Cd...2+ A concentration of around 225 mg / L may lead to inactivation. Although there are ongoing studies on improving the resistance of urease-producing bacteria, the above-mentioned problems cannot be effectively solved. Summary of the Invention

[0007] To address the problems existing in the prior art, the inventors of this invention, based on long-term research on microbial-induced carbonate deposition technology, provide an improved solution that efficiently solves the aforementioned technical problems. The passivation material provided by this invention is a porous bio-calcium carbonate with urease activity. Specific components of this material not only exert the heavy metal adsorption properties of porous bio-calcium carbonate but also maintain urease activity even in environments with extremely high concentrations of heavy metals, continuously exerting a biomineralization effect on residual heavy metals.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A method for preparing a porous bio-calcium carbonate passivating material with urease activity, comprising the following steps:

[0010] S1. Add urea and soluble calcium salt to the bacterial solution containing urease bacteria. The urease bacteria undergo a biomineralization reaction to generate a calcium carbonate slurry suspension with urease activity.

[0011] S2. After filtering the calcium carbonate slurry suspension, the filter residue is washed and freeze-dried to obtain a porous bio-calcium carbonate passivation material with urease activity.

[0012] Specifically, in step S1, the concentrations of both urea and soluble calcium salt are controlled to be between 0.1 mol / L and 0.8 mol / L.

[0013] The aforementioned bacterial culture containing urease-producing bacteria refers to the entire culture system containing culture medium residues, metabolites, and other components that has already cultured urease-producing bacteria; that is, the urease-producing bacteria used here do not need to be isolated from the culture system beforehand. The urease-producing bacteria can be *Bacillus pasteurellii* ATCC11859; correspondingly, the specific composition of its culture medium includes: 20 g / L–30 g / L yeast extract, 15 g / L–30 g / L ammonium chloride, 0–1 mmol / L nickel chloride, and a pH of 9.2–9.3.

[0014] The above-mentioned bacterial suspension containing urease can be obtained by inoculating the urease mother solution into a sterilized culture medium and shaking it at a temperature of about 30°C for about 1.5 days. Then, store it at 4°C for later use.

[0015] In step S1, before adding urea and soluble calcium salt, the activity of urease bacteria in the solution must be fixed to 10 U / mL to 30 U / mL using physiological saline.

[0016] Wherein, 1U represents the amount of urease-producing bacteria that can generate the urease required to hydrolyze 1 μmol of urea per minute.

[0017] The soluble calcium salts mentioned above can be calcium chloride, calcium acetate, or calcium nitrate.

[0018] In step S1, the biomineralization reaction can be achieved by stirring the above-mentioned bacterial solution, urea and soluble calcium salt mixture at a speed of 100 rpm to 600 rpm for 2 h to 24 h.

[0019] In step S2, the preferred conditions for the freeze-drying operation are: controlling the temperature of the freeze-dried sample (i.e., the cleaned filter residue) to be -40℃ to -30℃.

[0020] Furthermore, the freeze-drying process can be carried out for 24 hours to 48 hours.

[0021] Preferably, in step S2, the filter residue is obtained by vacuum filtration of a calcium carbonate slurry suspension; for example, vacuum filtration is performed under the condition that the pressure of the vacuum pump is controlled at 0.6MPa to 0.8MPa and the filter paper is medium-speed qualitative filter paper.

[0022] Another object of the present invention is to provide a porous bio-calcium carbonate passivation material with urease activity. The passivation material is a composite material comprising porous calcium carbonate of the aragonite crystal type and urease bacteria and the urease produced therefrom, with a urease activity of 150 U / g to 1000 U / g.

[0023] Another object of the present invention is to provide an application of the above-mentioned porous bio-calcium carbonate passivating material with urease activity in heavy metal remediation.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1) The passivation material prepared by the method described above in this invention has a porous structure, which not only provides more nucleation sites but also exhibits extremely high adsorption capacity for heavy metals. Specifically, it has a high adsorption capacity for the heavy metal Cd. 2+ The adsorption capacity is approximately 1000 mg / g, far exceeding the average level.

[0026] 2) The passivation material prepared by the above method provided by this invention significantly improves the resistance to heavy metal toxicity, overcoming the limitation of traditional MIP technology in removing heavy metal pollution by restricting the concentration of heavy metals. Simultaneously, utilizing its unique urease activity, adsorption and biomineralization can be effectively combined, not only effectively and thoroughly removing heavy metals, but also preventing secondary pollution by adding an additional calcium source to encapsulate the heavy metals within calcium carbonate.

[0027] 3) The preparation method provided by the present invention is simple, controllable, inexpensive, safe and pollution-free, and therefore easy to realize industrial production, with great potential for promotion and application value. Attached Figure Description

[0028] The above and other aspects, features, and advantages of embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 This is a photograph of the biomineralization reaction of urease bacteria according to Example 1 of the present invention.

[0030] Figure 2 This is a photograph of the urease-producing bacteria after the biomineralization reaction in Example 1 of the present invention.

[0031] Figure 3 This is a physical image of the passivation material according to Embodiment 1 of the present invention;

[0032] Figure 4 This is a SEM image of the passivation material according to Embodiment 1 of the present invention;

[0033] Figure 5 This is an XRD pattern of the passivation material according to Embodiment 1 of the present invention;

[0034] Figure 6 These are the stability test results of the passivation material according to Embodiment 1 of the present invention;

[0035] Figure 7 These are the toxicity test results of the passivation material according to Embodiment 1 of the present invention;

[0036] Figure 8 The results are stability test results of the comparative passivation material according to Comparative Example 1 of the present invention.

[0037] Figure 9 This is a comparison of the activity test results of the comparative passivation material in Comparative Example 2 and the passivation material in Example 1 according to the present invention;

[0038] Figure 10 This is a SEM image of the precipitate formed by the passivation material during the cadmium removal process in Application Example 1 of the present invention;

[0039] Figure 11 This is an XRD pattern of the precipitate after cadmium removal from the passivation material in Application Example 1 of the present invention;

[0040] Figure 12 This is a SEM image of the precipitate after cadmium removal from the passivation material in Application Example 1 of the present invention;

[0041] Figure 13This is a diagram showing the effect of passivation material on the removal of heavy metal cadmium in Application Example 1 of the present invention;

[0042] Figure 14 The results are the durability test results of the passivation material in Application Example 2 of the present invention. Detailed Implementation

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different forms, and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the various embodiments of the invention and various modifications suitable for particular intended applications.

[0044] Example 1

[0045] This embodiment provides a porous bio-calcium carbonate passivation material with urease activity, which is prepared by the following method.

[0046] First, take 500 mL of bacterial culture containing urease-producing bacteria, measure its urease activity using a conductivity meter, and then dilute it with physiological saline to a urease activity of about 20 U / mL.

[0047] Specifically, the bacterial culture was obtained by inoculating a mother liquor of urease bacteria into a sterilized culture medium and then shaking it at 30°C for 1.5 days.

[0048] The culture medium consists of 20 g / L yeast extract, 15 g / L ammonium chloride, and 1 mmol / L nickel chloride, mixed and then water is added to make up to 1 L. The pH of the culture medium is controlled at 9.25.

[0049] Then, take 250 mL of the above bacterial solution, add 6.006 g of urea and 11.098 g of calcium chloride to it, and stir the mixture at 300 rpm for 12 h. The urease bacteria undergo a biomineralization reaction to generate a calcium carbonate slurry suspension with urease activity.

[0050] like Figure 1 and Figure 2 As shown, Figure 1 The state of the above biomineralization reaction process is shown; the reaction system is in a chaotic state. Figure 2 The image shows the state of the suspension after a period of settling following the biomineralization reaction. It can be seen that the suspension gradually settles and separates into layers.

[0051] Finally, the suspension was poured into a vacuum filtration device for filtration. The filtered solids were washed three times with deionized water and then freeze-dried at -30°C for 48 hours. Finally, the solids were ground to obtain the final product.

[0052] Figure 3 The above-mentioned product is shown in its physical form, which is a white-gray powder.

[0053] The products obtained above were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively, and the characterization results are as follows: Figure 4 and Figure 5 As shown. From Figure 4 As can be seen, the product has a porous structure. And from... Figure 5 It can be seen that the main crystal is calcium carbonate, and it exhibits a vaterite crystal form. This specific morphology of the crystal composition ensures its heavy metal adsorption properties.

[0054] The product obtained above was tested for urease activity, and its urease activity was 350 U / g. This property ensures that it has heavy metal mineralization properties.

[0055] Therefore, this embodiment yields a porous bio-calcium carbonate passivation material with urease activity.

[0056] The stability of the passivation material was tested. Specifically, 10g of the passivation material was placed in environments at 4℃ and 25℃, respectively, and its urease activity was tested on days 1, 3, 14, 21, and 28. For each test, 0.1g of the passivation material was placed in 1.8mol / L urea, and its urease activity was expressed as the rate of change in ammonia nitrogen concentration over 30 minutes, in units of U / g.

[0057] Stability test results are as follows Figure 6 As shown, the urease activity of the passivation material did not decrease significantly within nearly a month, especially at 4℃, where it maintained more than 90% of its original activity over the course of a month. Furthermore, at 25℃, it still exhibited good urease activity, demonstrating its excellent thermal stability. This provides a promising prospect for its practical application.

[0058] The toxicity resistance of the above passivation material was tested. Specifically, 1g of the passivation material was placed in 150mL Erlenmeyer flasks containing heavy metal Cd concentrations of 0, 10mg / L, 20mg / L, 50mg / L, 100mg / L, 250mg / L, and 500mg / L, respectively; each flask contained 100mmol / L urea. The reaction was carried out in a shaker at 30℃ and 180rpm for 24h, and the change in ammonia nitrogen concentration in the aqueous solution during this period was measured.

[0059] Toxicity test results as follows Figure 7As shown, within a heavy metal Cd concentration range not exceeding 500 mg / L, although the reaction intensity is affected by the heavy metal, it still exhibits certain urease activity, and all reactions completely removed 100 mol / L urea within approximately 24 hours. This indicates that the passivation material has strong heavy metal tolerance and also demonstrates a strong potential for heavy metal removal, suggesting that this composite passivation material has better application prospects than simple passivating agents.

[0060] Example 2

[0061] In the description of Example 2, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 2 and Example 1 are as follows:

[0062] In the preparation method of the passivation material provided in Example 2, 1.5015g of urea and 11.098g of calcium chloride were added to 250mL of bacterial solution; and the solution was freeze-dried at -35°C for 42h; the rest was as described in Example 1, and a porous bio-calcium carbonate passivation material with urease activity was obtained.

[0063] The urease activity of the passivation material provided in this embodiment is 307 U / g.

[0064] Example 3

[0065] In the description of Example 3, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 3 and Example 1 are as follows:

[0066] In the preparation method of the passivation material provided in Example 3, 12.012g of urea and 22.1968g of calcium chloride were added to 250mL of bacterial solution; and the solution was freeze-dried at -40°C for 36h; the rest was as described in Example 1, and a porous bio-calcium carbonate passivation material with urease activity was obtained.

[0067] The urease activity of the passivation material provided in this embodiment is 151 U / g.

[0068] Example 4

[0069] In the description of Example 4, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 4 and Example 1 are as follows:

[0070] In the preparation method of the passivation material provided in Example 4, the bacterial solution of urease-producing bacteria was diluted with physiological saline to a urease activity of about 30 U / mL; the rest was as described in Example 1, and a porous biological calcium carbonate passivation material with urease activity was obtained.

[0071] The urease activity of the passivation material provided in this embodiment is 298 U / g.

[0072] Example 5

[0073] In the description of Example 5, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 5 and Example 1 are as follows:

[0074] In the preparation method of the passivation material provided in Example 5, the bacterial solution of urease-containing bacteria was diluted with physiological saline to a urease activity of about 10 U / mL; 6.006 g of urea and 2.7746 g of calcium chloride were added to 250 mL of bacterial solution; and the solution was freeze-dried at -40°C for 24 h; the rest was as described in Example 1, and a porous bio-calcium carbonate passivation material with urease activity was obtained.

[0075] The urease activity of the passivation material provided in this embodiment is 998 U / g.

[0076] Example 6

[0077] In the description of Example 6, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 6 and Example 1 are as follows:

[0078] In the preparation method of the passivation material provided in Example 6, the bacterial solution of urease-containing bacteria used has the following composition of culture medium: 20 g / L yeast powder, 30 g / L ammonium chloride, and water added to make up to 1 L, and the pH of the culture medium is controlled at 9.2; the rest is as described in Example 1, to obtain a porous biological calcium carbonate passivation material with urease activity.

[0079] The urease activity of the passivation material provided in this embodiment is 301 U / g.

[0080] Example 7

[0081] In the description of Example 7, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between Example 7 and Example 1 are as follows:

[0082] In the preparation method of the passivation material provided in Example 7, the bacterial solution of urease-containing bacteria used has the following composition of culture medium: 30 g / L yeast powder, 25 g / L ammonium chloride, and 0.5 mmol / L nickel chloride are mixed and water is added to make up to 1 L, and the pH of the culture medium is controlled at 9.3; the rest is as described in Example 1, and a porous biological calcium carbonate passivation material with urease activity is obtained.

[0083] The urease activity of the passivation material provided in this embodiment is 303 U / g.

[0084] In the preparation process of the passivation material provided by the present invention, on the one hand, the urease bacteria provided are not a single species, but a mixture of bacterial solutions from which urease bacteria have been cultured; on the other hand, the drying method of the filter residue obtained from the suspension has a significant impact on obtaining the product with the above-mentioned specific morphological components and excellent application performance.

[0085] Regarding the first influencing factor mentioned above, based on the inventor's previous research, if the extracted urease bacteria are directly mixed with urea and soluble calcium salts, the calcium carbonate crystals obtained after drying and deposition will only be calcite, not the aragonite in this invention.

[0086] The following comparative experiment was conducted to address the second influencing factor mentioned above.

[0087] Comparative Example 1

[0088] In this comparative example, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between this comparative example and Example 1 are as follows:

[0089] The calcium carbonate slurry suspension with urease activity prepared in this comparative example was vacuum filtered, the filter residue was washed, and then divided into two portions. These portions were placed at 4°C and 25°C respectively for natural drying, instead of using the freeze-drying method in Example 1, to obtain the first comparative passivation material and the second comparative passivation material.

[0090] The stability of the two comparative passivation materials was tested using the same test method, and the test results are as follows: Figure 8 As shown. From Figure 8 As can be seen, the stability of products not prepared by freeze-drying decreased significantly. Products obtained by natural drying at room temperature (25°C) showed a particularly rapid decline in urease activity, almost completely losing its activity by around day 7, rendering them unusable. Even products dried at a lower temperature of 4°C showed a rapid decrease in urease activity after day 7.

[0091] Comparative Example 2

[0092] In this comparative example, the similarities with Example 1 will not be repeated here; only the differences from Example 1 will be described. The differences between this comparative example and Example 1 are as follows:

[0093] The calcium carbonate slurry suspension with urease activity prepared in this comparative example was vacuum filtered, the filter residue was washed, and then dried at about 60°C, instead of using the freeze-drying method in Example 1, to obtain the third comparative passivation material.

[0094] The urease activity of the comparative passivation material was tested and compared with the results in Example 1. Figure 9 As shown in the figure, "freeze-drying" refers to the activity data in Example 1, while "high-temperature drying" refers to the activity data in this comparative example. It can be seen that when drying is performed at approximately 60°C, the urease-producing bacteria in the obtained product are almost completely inactivated. Therefore, the product obtained by this drying method cannot perform biomineralization in application.

[0095] The passivation material provided by this invention, based on its specific structure and properties, can exert a dual effect of adsorption and mineralization on heavy metals, and therefore can be applied in the field of heavy metal remediation. The following application examples are provided for this purpose.

[0096] Application Example 1

[0097] The passivation material provided in Example 1 above was applied to the removal of the heavy metal cadmium.

[0098] Take 0.1g of passivation material and put it into a 300mL solution of cadmium heavy metal with a concentration of 400mg / L to allow the removal rate of cadmium heavy metal ... cadmium to reach equilibrium.

[0099] During the removal process described above (approximately 10 hours), a portion of the precipitate was collected and subjected to scanning electron microscopy (SEM) analysis. The SEM image is shown below. Figure 10 As shown in Figure 11. After reaching removal equilibrium (approximately 10 days), a portion of the precipitate was taken and subjected to X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The XRD patterns and SEM images are shown in Figure 11 and Figure 12, respectively. Figure 12 As shown.

[0100] from Figure 10 It can be seen from this that Figure 4 The porous spheres exhibit partial bulk crystal formation outside the structure; in contrast Figure 12 It can be seen that the bulk crystals are increasing in number and gradually covering the outer surface of the porous sphere. Combined with... Figure 11 The results show that the blocky crystals on the outer surface of the porous calcium carbonate spheres are cadmium carbonate produced by passivating the heavy metal cadmium, and its crystal form is cadmium ore.

[0101] The concentration change of heavy metal cadmium during the above process was measured using an ICP-OES instrument, and the removal effect was as follows: Figure 13 As shown. From Figure 13 As can be seen, the passivation material has an excellent removal effect on high concentrations of the heavy metal cadmium.

[0102] Application Example 2

[0103] This application example tested the durability of the passivation material provided in Example 1.

[0104] Specifically, 0.1 g of passivation material was placed in 150 mL Erlenmeyer flasks containing cadmium concentrations of 0, 10 mg / L, 50 mg / L, 150 mg / L, 300 mg / L, and 500 mg / L, respectively. After 24 hours of poisoning in a cadmium ion environment, urea was added to bring the concentration to 0.1 mol / L. The reaction was carried out for 48 hours in a shaker at 30°C and 180 rpm, and the change in ammonia nitrogen concentration during this stage was measured.

[0105] The durability test results are as follows: Figure 14 As shown. From Figure 14 As can be seen, the passivation material can still effectively retain its urease activity under low concentration of heavy metal cadmium, and can continue to undergo biomineralization reaction after the addition of urea, indicating that it has good toxicity resistance and durability.

[0106] Based on this excellent durability, it is known that if soluble calcium salts are continuously added as a calcium source, the urease activity it exhibits can continue to decompose urea to produce carbonate ions, which then react with these newly added calcium ions to form calcium carbonate. At the same time, the precipitate particles generated after the heavy metal passivation has been completed provide growth sites, allowing these newly generated calcium carbonates to coat the heavy metal carbonates, thereby preventing secondary pollution by heavy metals. This creates very favorable conditions for its use in practical applications.

[0107] Although the invention has been shown and described with reference to specific embodiments, those skilled in the art will understand that various changes in form and detail may be made herein without departing from the spirit and scope of the invention as defined by the claims and their equivalents.

Claims

1. A method for preparing a porous bio-calcium carbonate passivating material with urease activity, characterized in that, Including the following steps: S1. Urea and soluble calcium salts are added to the bacterial solution containing urease-producing bacteria, causing the urease-producing bacteria to undergo a biomineralization reaction, generating a calcium carbonate slurry suspension with urease activity; wherein the bacterial solution containing urease-producing bacteria is a mixed system obtained by inoculating a urease-producing bacteria stock solution into a culture medium, culturing, and adjusting the urease activity, and wherein the urease activity of the urease-producing bacteria is 10 U / mL~30 U / mL; the urease-producing bacteria is Bacillus pasteurellii; S2. After filtering the calcium carbonate slurry suspension, the filter residue is washed and freeze-dried to obtain a porous bio-calcium carbonate passivation material with urease activity.

2. The preparation method according to claim 1, characterized in that, The amount of urea and the soluble calcium salt added is controlled so that the concentration after addition is 0.1 mol / L to 0.8 mol / L.

3. The preparation method according to claim 2, characterized in that, The soluble calcium salt is selected from calcium chloride, calcium acetate, and calcium nitrate.

4. The preparation method according to claim 1, characterized in that, The culture medium comprises: 20 g / L to 30 g / L yeast extract, 15 g / L to 30 g / L ammonium chloride, and 0 to 1 mmol / L nickel chloride, and the pH of the culture medium is 9.2 to 9.

3.

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step S2, the sample temperature is controlled at -40℃ to -30℃ for freeze-drying.

6. The preparation method according to claim 5, characterized in that, In step S2, the freeze-drying time is 24 h to 48 h.

7. A porous bio-calcium carbonate passivation material with urease activity, characterized in that, The porous bio-calcium carbonate passivating material with urease activity is obtained by any of the preparation methods described in claims 1 to 6. It is a composite material comprising a porous calcium carbonate skeleton with a spheroidal morphology and urease bacteria and the urease produced therefrom, and the urease activity is 150 U / g to 1000 U / g.

8. The application of the porous bio-calcium carbonate passivating material with urease activity as described in claim 7 in cadmium pollution remediation.

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