A method for mineralizing and recovering dysprosium ions from Bacillus pasteurization
By using Bacillus pasteurella to induce biomineralization under the influence of calcium and urea, the problems of complex processes and secondary pollution in rare earth wastewater treatment have been solved. This method achieves efficient recovery of rare earth ions, reaching a recovery rate of 98.4%, while avoiding secondary pollution and reducing equipment requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGXI UNIV OF SCI & TECH
- Filing Date
- 2023-09-14
- Publication Date
- 2026-05-26
AI Technical Summary
Existing rare earth wastewater treatment technologies are complex and prone to secondary pollution, with low rare earth ion recovery rates. Biological recovery methods rely on cell activity and are easily affected by the environment, and no research has been found on the application of biomineralization technology for rare earth ion recovery.
Bacillus pasteurellii was used for biomineralization under the induction of calcium source and urea. The pH value was adjusted to form calcium carbonate embedded precipitate, and rare earth precipitate was obtained by direct filtration without centrifugation. The strain could not survive in the absence of urea, providing nucleation sites and decomposing urea to adjust the pH value.
It achieves a rare earth ion recovery rate of up to 98.4%, is easy to operate, green and pollution-free, and has a wide range of applications, including the recovery of rare earth mine wastewater.
Smart Images
Figure CN117210683B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bio-environmental protection technology, and in particular relates to a method for mineralizing and recovering dysprosium ions using Bacillus pasteurella multocida. Background Technology
[0002] Rare earth elements are a collective term for 17 elements in Group IIIB of the periodic table, including scandium (Sc), yttrium (Y), and lanthanum (La). Among them, gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and yttrium (Y) belong to the heavy rare earth category. Rare earth elements are non-renewable national strategic resources with important applications in high-tech and military industries. Dysprosium is a relatively abundant heavy rare earth element, providing a good resource base for its applications. In addition to the chemical reactivity common to rare earth elements, dysprosium also possesses excellent optical, electrical, magnetic, and nuclear properties, making it suitable for manufacturing various functional materials and playing a unique role in many high-tech fields.
[0003] The rare earth mines in Ganzhou, Jiangxi Province, primarily produce ion-adsorption rare earth elements. However, due to relatively low technological barriers to mining and weak environmental awareness, this has led to resource waste and environmental pollution. Rare earth mining processes easily generate large amounts of wastewater, with rare earth ion concentrations reaching as high as 200 mg / L, while the daily allowable intake of rare earth elements for adults is approximately 4.2 mg. Therefore, to ensure public health and safety and to fully utilize rare earth resources, green and efficient technologies are urgently needed to address the issues of rare earth wastewater pollution and resource recovery.
[0004] Currently, numerous physical and chemical recovery technologies related to rare earths have been reported. For example, Chinese patent application CN108726555A discloses a method for rare earth recovery based on ionic liquid precipitation. This involves first synthesizing a solid carboxylic acid compound, then forming a hydrophobic ionic liquid precipitant with large cations through ion exchange and acid-base neutralization reactions. This precipitant is then selectively precipitated with a rare earth-containing solution to recover rare earth ions. However, these technologies have relatively complex processes, generally poor rare earth ion recovery rates, and are prone to causing secondary pollution. In contrast, biological methods for rare earth recovery offer advantages such as simple processes and economic and environmental benefits. For instance, Chinese patent application CN 110938565A discloses a Bacillus cereus strain and its method for rare earth ion recovery. This involves culturing and collecting Bacillus cereus DW019 cells, then incubating them in a solution containing rare earth ions to collect the cells loaded with rare earth ions. After elution with ethylenediaminetetraacetic acid solution, the rare earth ions are recovered by centrifugation, achieving a high recovery rate for 17 rare earth ions. However, this adsorption method is highly dependent on the active groups on the cell surface, and its main functions of electrostatic attraction and ion exchange are easily affected by environmental pH and cell activity.
[0005] Biomineralization refers to the process by which organisms generate inorganic minerals through the regulation of biological macromolecules, including controlled mineralization and induced mineralization. Biomineralization technology is generally applied in building remediation and heavy metal pollution treatment. Chinese patent application CN 107460143 A discloses a Bacillus cereus strain capable of bioactivating and mineralizing the heavy metal cadmium. This strain lowers the soil pH in the early stages of cultivation, increasing the activity of cadmium ions; in the later stages, it raises the soil pH, increasing the adsorption and precipitation of heavy metals on the bacterial cells. Subsequently, through biomineralization, cadmium ions are converted into cadmium sulfides and phosphates, reducing the biotoxicity of cadmium ions and making it suitable for remediating cadmium-contaminated soil. However, no research reports have been found on the application of biomineralization technology for rare earth ion recovery. Summary of the Invention
[0006] To address the problems existing in the prior art, this invention attempts to apply biomineralization technology to the recovery of rare earth ions. Unexpectedly, it was discovered that cultured *Bacillus pasteurellii* can undergo biomineralization under the conditions of providing an induction solution with a certain concentration of calcium source and urea (pH 5-7). *Bacillus pasteurellii* provides nucleation sites on one hand, and rapidly decomposes urea to adjust the pH and provide CO3 on the other. 2- This stabilizes the pH of the urea decomposition system between 9.0 and 9.5, effectively inducing the mineralization of dysprosium ions (Dy). 3+ (This) forms a precipitate. The method provided by this invention does not require the removal of Dy-containing substances. 3+ After pretreatment of the solution and biomineralization, it can be directly filtered to obtain rare earth Dy. 3+ The precipitate requires no centrifugation, making the operation simple and the entire process green and pollution-free. The strain itself is non-pathogenic and cannot survive in a urea-free environment. After induced mineralization, the cells die due to calcium carbonate encapsulation, thus causing neither secondary pollution nor invasive species hazards. This method Dy 3+ With a recovery rate as high as 98.4%, and a wide range of application conditions, it can be widely used in rare earth mine wastewater treatment. 3+ Recycling.
[0007] This invention provides a method for mineralizing and recovering dysprosium ions using Bacillus pasteurella, comprising the following steps:
[0008] 1) Cell culture: Inoculate activated Pasteurella multocida into CASO liquid medium, culture for 22-26 h, centrifuge, and collect the cell bodies;
[0009] 2) Bacillus pasteurellium-induced mineralization: The bacterial cells collected in step 1) were incubated with an induction solution containing calcium source, urea and dysprosium ions, and the precipitate containing dysprosium after mineralization was obtained by filtration.
[0010] Using the above technical solution, after incubating Bacillus pasteurellii with an induction solution containing calcium source, urea, and dysprosium ions, the mineralized dysprosium-containing precipitate is obtained by filtration without centrifugation, thus achieving the treatment of Dysprosium. 3+ Highly efficient recycling, Dy 3+ The recovery rate is as high as 98.4%.
[0011] Preferably, the incubation temperature is 15–30°C and the incubation time is 10–120 min.
[0012] Preferably, in the induction solution, the calcium source is calcium chloride, the concentration of calcium ions is 20-30 mmol / L, and the concentration of urea is 1.5%-2.5% w / w.
[0013] Preferably, the concentration of dysprosium ions in the induction solution is 50–500 μmol / L.
[0014] Preferably, the concentration of the bacterial cells collected in step 1) is OD. 600 =0.7~1.2.
[0015] Preferably, step 2) further includes the following steps: slowly adding hydrochloric acid to the precipitate to dissolve it until no more bubbles are produced, then eluting it 4 to 6 times with pyridine dicarboxylic acid solution or ethylenediaminetetraacetic acid solution, centrifuging to collect the supernatant, thus obtaining the recovery solution containing dysprosium ions.
[0016] Preferably, the concentration of the pyridine dicarboxylic acid solution is 8–12 mmol / L, and the concentration of the ethylenediaminetetraacetic acid solution is 0.2–0.3 mol / L.
[0017] Preferably, the preparation method of the CASO liquid culture medium includes the following steps: adding 15g of tryptone, 5g of soybean peptone, and 5g of NaCl to 850mL of water, adjusting the pH value to 7.3 with 1mol / L NaOH solution and making up the volume to 900mL, autoclaving and cooling, and then adding 100mL of 20% w / w urea solution that has been filtered and sterilized.
[0018] Preferably, the Bacillus pasteurii is Sporosarcina pasteurii, purchased from the Beijing Culture Collection Center, with the number ATCC11859.
[0019] Preferably, in step 1), the centrifugation speed is 3000–5000 rpm, and the time is 8–12 min. The centrifugation speed for collecting the bacterial cells in step 1) should not be too high, as this will affect bacterial activity and lead to a poorer subsequent biomineralization effect.
[0020] Compared with the prior art, the beneficial effects of the present invention include: The present invention provides a method for mineralizing and recovering dysprosium ions using Bacillus pasteurellium. Under the conditions of providing an inducing solution with a certain concentration of calcium source and urea (pH value of 5-7), cultured Bacillus pasteurellium can undergo biomineralization. Bacillus pasteurellium provides nucleation sites on the one hand, and can rapidly decompose urea to adjust the pH and provide CO3 on the other hand. 2- This stabilizes the pH of the urea decomposition system between 9.0 and 9.5, effectively inducing mineralization of Dy. 3+ A precipitate forms. The method provided by this invention eliminates the need for treatment of Dy-containing substances. 3+ The solution undergoes pretreatment, and after biomineralization, the dysprosium-containing precipitate can be directly filtered out without centrifugation. The operation is simple and requires minimal equipment. The entire process is green and pollution-free. The strain itself is non-pathogenic and cannot survive in a urea-free environment. Cells die after induced mineralization due to calcium carbonate encapsulation, thus preventing secondary pollution and invasive species hazards. This method Dy 3+ With a recovery rate as high as 98.4%, and a wide range of application conditions, it can be widely used in rare earth mine wastewater treatment. 3+ Recycling. Attached Figure Description
[0021] Figure 1 Phase contrast microscopy images of Bacillus pasteurellii; the left image is before mineralization, and the right image is after mineralization.
[0022] Figure 2 Growth curves, pH values, and urease activity changes of Bacillus pasteurellii.
[0023] Figure 3 Bacillus pasteurellis against 400 μmol / L Dy 3+ Comparison of cell adsorption and induced mineralization recovery results.
[0024] Figure 4 Pasteurella multocida showed positive effects against 400 μmol / L Dy250 using two different recovery treatment methods. 3+ Comparison of induced mineralization recovery results.
[0025] Figure 5 Bacillus pasteurellis against 400 μmol / L Dy 3+ and Tb 3+ Comparison of induced mineralization recovery results. Detailed Implementation
[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0027] In this invention, the culture media and related materials involved are all conventional commercially available products, or can be obtained through conventional technical means in this field. The preparation method of CASO liquid culture medium includes the following steps: add 15g of tryptone, 5g of soybean peptone, and 5g of NaCl to 850mL of water, adjust the pH value to 7.3 with 1mol / L NaOH solution and make up the volume to 900mL, autoclave and cool, and then add 100mL of 20% w / w urea solution that has been filtered and sterilized.
[0028] Example 1: Method for mineralizing and recovering dysprosium ions using Bacillus pasteurization
[0029] A method for mineralizing and recovering dysprosium ions using Bacillus pasteurellium includes the following steps:
[0030] 1) Cell culture: Activated Pasteurella multocida were inoculated into CASO liquid medium and cultured at 30°C for 24 h. The cells were collected by centrifugation at 4000 rpm for 10 min.
[0031] 2) Bacillus pasteurellium-induced mineralization: The bacterial cells collected in step 1) (OD of the bacterial cells in the induction solution) 600 1) The sample was incubated with an induction solution containing 25 mmol / L CaCl2, 2% w / w urea, and 400 μmol / L Ly(NO3)3 at 25°C. The precipitate containing dysprosium after mineralization was obtained by filtration. Hydrochloric acid was slowly added to the precipitate to dissolve it until no more bubbles were produced. The precipitate was then eluted five times with 10 mmol / L pyridine dicarboxylic acid (DPA) solution to remove all dysprosium. After centrifugation at 12000 rpm for 4 min, the supernatant was collected to obtain the dysprosium-containing recovery solution.
[0032] Phase contrast microscopy image of Bacillus pasteurellis as follows Figure 1 As shown; the left figure is before mineralization, and the right figure is after mineralization. The growth curves, pH values, and urease activity changes of *Bacillus pasteurellii* are shown in the figure below. Figure 2 As shown. During incubation, the supernatant was taken at regular intervals to measure the Dy content in the supernatant. 3+ Concentration, calculation: Dy 3+ Removal rate % = (initial ion concentration - supernatant ion concentration) / initial ion concentration × 100%, induced mineralization and cell adsorption on Dy 3+ The recycling effect is for example Figure 3 As shown.
[0033] This invention utilizes the characteristics of Bacillus pasteurellii to successfully induce mineralization of Dy by introducing a calcium source and urea. 3+ Separation and recycling. As demonstrated in Example 1, the method provided by this invention has a good recycling effect. From Figure 3 It can be seen that the Pasteurella cells themselves are affected by Dy3+ The adsorption capacity is limited, with a maximum recovery rate of only 73.6%; while induced mineralization can up to [amount missing] Dy 3+ The recovery rate increased to 98.4%. Figure 4 It can be seen that after 20 minutes of treatment, Bacillus pasteurellium essentially destroyed Dy 3+ In a fully mineralized precipitate, even without centrifugation, the supernatant contains almost no free Dy. 3+ .
[0034] Following the above method for mineralizing and recovering dysprosium ions using Bacillus pasteurellium, the effects of Bacillus pasteurellium on 400 μmol / LDy were investigated. 3+ and Tb 3+ The induced mineralization recovery was assessed, and centrifugation was performed after incubation. The results were compared as follows: Figure 5 As shown. By Figure 5 It can be seen that, under the same treatment conditions, comparing Tb 3+ The mineralization and recovery effect of Bacillus pasteurellis mineralization treatment Dy 3+ The recovery rate is significantly higher, increasing by up to 17.7%; and the mineralization recovery effect is more stable, with the recovery rate remaining stable at over 97.8%.
[0035] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for mineralizing and recovering dysprosium ions using Bacillus pasteurization, characterized in that: Includes the following steps: 1) Cell culture: Inoculate activated Pasteurella multocida into CASO liquid medium, culture for 22-26 h, centrifuge, and collect the cell bodies; 2) Bacillus pasteurellium-induced mineralization: The cells collected in step 1) were incubated with an induction solution containing calcium source, urea and dysprosium ions, and the precipitate containing dysprosium after mineralization was obtained by filtration. The incubation temperature is 15–32°C, and the time is 10–120 min; in the induction solution, the calcium source is calcium chloride, the concentration of calcium ions is 20–30 mmol / L, and the concentration of urea is 1.5%–2.5% w / w.
2. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: The concentration of dysprosium ions in the induction solution is 50–500 μmol / L.
3. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: The concentration of the bacterial cells collected in step 1) is OD. 600 =0.7~1.
2.
4. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: Step 2) further includes the following steps: slowly adding hydrochloric acid to the precipitate to dissolve it until no more bubbles are produced, then eluting it 4 to 6 times with pyridine dicarboxylic acid solution or ethylenediaminetetraacetic acid solution, centrifuging to collect the supernatant, thus obtaining the recovery solution containing dysprosium ions.
5. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 4, characterized in that: The concentration of the pyridine dicarboxylic acid solution is 8–12 mmol / L, and the concentration of the ethylenediaminetetraacetic acid solution is 0.2–0.3 mol / L.
6. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: The preparation method of the CASO liquid culture medium includes the following steps: add 15g of tryptone, 5g of soybean peptone, and 5g of NaCl to 850mL of water, adjust the pH value to 7.3 with 1mol / L NaOH solution and make up the volume to 900mL, autoclave and cool, and then add 100mL of 20% w / w urea solution that has been filtered and sterilized.
7. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: The *Sporosarcina pasteurii* strain was purchased from the Beijing Culture Collection Center, with the serial number ATCC11859.
8. The method for mineralizing and recovering dysprosium ions using Bacillus pasteurization according to claim 1, characterized in that: In step 1), the centrifugation speed is 3000-5000 rpm and the time is 8-12 min.