Method for absorbing lithium by utilizing algae strains

Abstract

The invention relates to the field of metal recovery, and discloses a method for absorbing lithium by utilizing an algae strain, which is characterized by comprising the following steps: adding auxin with specified concentration into an algae culture medium containing lithium element, and growing the algae strain for specified time under the conditions that the pH value is 7-8 and the temperature is 32 + / -2 DEG C, so as to absorb the lithium element in the algae culture medium through the algae strain. According to the method disclosed by the invention, the lithium element is absorbed by utilizing the algae strains, the biological sustainability is realized, and compared with the traditional physical and chemical methods, the biological adsorption method is more environment-friendly, and the generation of chemical wastes is reduced.

Description

Technical Field

[0001] The present invention relates to the field of metal recycling, and particularly to a method for absorbing lithium using an algal strain. Background Art

[0002] Microcystis aeruginosa is a cyanobacterium and one of the Cyanobacteria. It is a single-celled alga that usually shows green or blue-green cells and lives in freshwater environments such as lakes, ponds, and rivers. The growth of Microcystis aeruginosa is usually affected by environmental factors such as light, water temperature, and nutrient concentration.

[0003] Some existing studies and experiments have shown that Microcystis aeruginosa has a certain potential for absorbing lithium, but the absorption efficiency is affected by various factors, including lithium concentration, temperature, pH value, nutrient concentration, etc. Currently, no specific commercial products or industrialization projects have emerged. Therefore, the application of Microcystis aeruginosa in absorbing lithium in wastewater treatment still faces some challenges and deficiencies, such as low absorption efficiency, high cultivation cost, slow treatment speed, etc. Summary of the Invention

[0004] In view of the problems in the prior art, the present invention provides a method for absorbing lithium using an algal strain to improve the efficiency of the algal strain in absorbing lithium.

[0005] A method for absorbing lithium using an algal strain includes:

[0006] Adding a specified concentration of auxin to an algal culture medium containing lithium, and under the conditions of pH = 7 - 8 and a temperature of 32 ± 2 °C, the algal strain grows for a specified time to absorb the lithium in the algal culture medium through the algal strain.

[0007] Optionally, the algal strain is Microcystis aeruginosa.

[0008] Optionally, the initial concentration of the lithium is less than or equal to 0.1 mol / L.

[0009] Optionally, the algal culture medium includes:

[0010] Sodium nitrate: 1.5 g / L;

[0011] Potassium dihydrogen phosphate: 0.04 g / L;

[0012] Potassium hydrogen phosphate: 0.075 g / L;

[0013] Magnesium sulfate heptahydrate: 0.075 g / L;

[0014] Calcium sulfate: 0.036 g / L;

[0015] Ammonium iron(III) nitrate dodecahydrate: 0.006 g / L;

[0016] Sodium carbonate: 0.02 g / L;

[0017] Trace element solution: 1 mL / L.

[0018] Optionally, the trace element solution includes:

[0019] Manganese(II) chloride tetrahydrate: 0.4 g / L;

[0020] Zinc sulfate heptahydrate: 0.1 g / L;

[0021] Copper(II) sulfate pentahydrate: 0.8 g / L;

[0022] Sodium molybdate dihydrate: 0.1 g / L;

[0023] Cobalt(II) nitrate hexahydrate: 0.2 g / L.

[0024] Optionally, the specified concentration includes 0.1 - 10 mg / L.

[0025] Optionally, the auxin includes at least one of oskar, biotin, lipoic acid, and silicic acid.

[0026] Optionally, the algal culture medium further includes an organic carbon source; the organic carbon source includes glucose and / or agarose.

[0027] Optionally, the concentration of the organic carbon source is 0.01% - 0.1% wt.

[0028] Optionally, the specified time is 7 days.

[0029] The high temperature and neutral to alkaline pH conditions provided in this example are conducive to the growth of algal strains and can improve the absorption of lithium by algal strains. The experimental results show that the algal strains can reduce the concentration of lithium from 0.1 mol / L to 0.03 mol / L. Since the absorption of lithium by algal strains is biocompatible, this biosorption method is more environmentally friendly than traditional physical and chemical methods and reduces the generation of chemical waste. Detailed implementation

[0030] In order to make the technical problems, technical solutions, and beneficial effects solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The embodiment of the present invention provides a method for absorbing lithium using algal strains, including:

[0032] Add auxin at a specified concentration to an algal culture medium containing lithium. Under the conditions of pH = 7 - 8 and a temperature of 32 ± 2 °C, the algal strain grows for a specified time to absorb lithium in the algal culture medium through the algal strain.

[0033] Understandably, an algal culture medium is a specific medium for culturing algae. The corresponding medium formula can be selected according to different algae to provide the specific nutrients and environmental conditions required for their growth. For example, the algal culture media that can be selected include BG11 medium, F / 2 medium, and Z8 medium. The algal culture medium used in this application is a medium improved for lithium-absorbing algal strains based on BG11 medium.

[0034] Auxin is a class of endogenous hormones containing an unsaturated aromatic ring and an acetic acid side chain, and it plays an important role in the growth and development of algae. An appropriate amount of auxin can stimulate the elongation and division of algal cells, thus promoting the growth of algae.

[0035] Different algae have different optimal pH values. It has been found through experiments that the pH suitable for the growth of the algal strain in this application is 7 - 8.

[0036] Temperature also has an important impact on the growth of algae. It has been found through experiments that the temperature suitable for the growth of the algal strain in this application is 32 ± 2 °C.

[0037] The specified time is the growth time for the algal strain to absorb lithium. The absorption efficiency of lithium by the algal strain is different at different times. In the initial stage of growth, the lithium ion concentration is high, but the concentration of the algal strain is low, and the absorption efficiency of lithium is low. In the final stage of growth, the lithium ion concentration is low, but the concentration of the algal strain is high, and the absorption efficiency is not high either. Therefore, it is necessary to select an appropriate specified time as the growth time for the algal strain to absorb lithium to maximize the absorption efficiency of lithium by the algal strain.

[0038] Optionally, the initial concentration of the lithium element is less than or equal to 0.1 mol / L.

[0039] Understandably, the initial concentration of the lithium element should not be too high, otherwise it will inhibit the growth of the algal strain. It has been found through testing that the initial concentration of the lithium element is less than or equal to 0.1 mol / L.

[0040] Optionally, the algal strain is Microcystis aeruginosa.

[0041] Understandably, Microcystis aeruginosa is an algae of the genus Microcystis of the family Chrococochaetaceae. Its plant masses are large, visible to the naked eye, and are olive green or dirty green. After maturity, it becomes a hollow capsule. As the colony continues to grow, some areas of the gelatinous membrane are broken or perforated, making the colony a pane-like capsule or an irregular lobed reticulate body. The cells of Microcystis aeruginosa are spherical or nearly spherical, and the cells are evenly distributed in the colony. Microcystis aeruginosa is widely distributed and has a low acquisition cost, which can reduce the cost of absorbing lithium.

[0042] Optionally, the algae culture medium comprises:

[0043] Sodium nitrate: 1.5 g / L;

[0044] Potassium dihydrogen phosphate: 0.04g / L;

[0045] Potassium monohydrogen phosphate: 0.075g / L;

[0046] Magnesium sulfate heptahydrate: 0.075 g / L;

[0047] Calcium sulfate: 0.036 g / L;

[0048] Ammonium ferric nitrate dodecahydrate: 0.006 g / L;

[0049] Sodium carbonate: 0.02g / L;

[0050] Trace element solution: 1mL / L.

[0051] Understandably, sodium nitrate and ammonium ferric nitrate dodecahydrate in the algae culture medium are nitrogen sources for algae strains. Inorganic salts such as phosphates participate in various biochemical processes in algae cells, such as energy conversion and metabolic regulation. Potassium salts, magnesium salts, calcium salts, etc. also help maintain the osmotic pressure and ion balance in algae cells, thereby ensuring the normal physiological functions of cells.

[0052] Optionally, the trace element solution comprises:

[0053] Manganese chloride tetrahydrate: 0.4 g / L;

[0054] Zinc sulfate heptahydrate: 0.1 g / L;

[0055] Copper sulfate pentahydrate: 0.8 g / L;

[0056] Sodium molybdate dihydrate: 0.1 g / L;

[0057] Cobalt nitrate hexahydrate: 0.2g / L.

[0058] Understandably, trace elements play an important role in the growth of algal strains. Although the content of trace elements in algae is very small, they are essential for maintaining the normal growth and metabolic activities of algae. These trace elements can serve as the active centers or activators of enzymes in algae, participate in various metabolic reactions in algae, and promote the growth and development of algae.

[0059] Optionally, the specified concentration includes 0.1 to 10 mg / L.

[0060] Optionally, the auxin includes at least one of oscar, biotin, lipoic acid, and silicic acid.

[0061] Understandably, auxin is a class of endogenous hormones containing an unsaturated aromatic ring and an acetic acid side chain, and it plays an important role in the growth and development of algae. An appropriate amount of auxin can stimulate the elongation and division of algal cells, thus promoting the growth of algae. Here, auxin includes oscar, biotin, lipoic acid, and silicic acid.

[0062] Oscar (N6-benzylaminopurine) is a plant growth regulator, also known as 6-benzyladenine. It is a synthetic plant hormone analog that can promote plant cell division and differentiation, thus promoting plant growth. The concentration range of oscar is 0.1 to 10 mg / L, preferably 1 mg / L.

[0063] Biotin is a water-soluble vitamin, also known as vitamin H or vitamin B7. It plays an important physiological function in algae, especially playing a key role in carbohydrate, fat, and protein metabolism. Biotin is a coenzyme of many enzymes and participates in a variety of metabolic processes, including glucose production, fatty acid synthesis, amino acid metabolism, etc. The concentration range of biotin is 0.1 mg / L.

[0064] Lipoic acid, also known as vitamin B1, is an important water-soluble vitamin. It participates in a variety of metabolic processes, such as carbohydrate metabolism. The concentration range of lipoic acid is 0.05 mg / L.

[0065] Silicic acid can accelerate the growth of diatoms and increase the formation of their siliceous shells. The concentration range of silicic acid is 0.05 mg / L, preferably 2 mg / L.

[0066] Optionally, the algal culture medium further includes an organic carbon source; the organic carbon source includes glucose and / or agarose.

[0067] Optionally, the concentration of the organic carbon source is 0.01% to 0.1% wt.

[0068] Understandably, organic carbon sources, such as glucose or agarose, can provide energy and carbon sources for Microcystis aeruginosa, promoting its growth and reproduction. The addition of organic carbon can increase the nutrient content in the water body, providing a richer nutrient environment for Microcystis aeruginosa, thereby promoting its growth.

[0069] Organic carbon sources may also affect the morphology and physiological characteristics of Microcystis aeruginosa. For example, the addition of certain organic carbon sources may cause changes in the cell structure or physiological metabolism of Microcystis aeruginosa.

[0070] The addition of organic carbon sources may change the structure of different microbial communities in the water body, thereby affecting the competitive relationship between Microcystis aeruginosa and other microorganisms. Under specific conditions, changes in organic carbon sources may lead to changes in the relative competitive advantage of Microcystis aeruginosa.

[0071] Optionally, the specified time is 7 days.

[0072] Understandably, the specified time is the growth time for the algal strain to absorb lithium. Through experiments, it was found that the specified time suitable for the growth of the algal strain in this application is 7 days.

[0073] The high-temperature and neutral to alkaline pH conditions provided in this example are conducive to the growth of the algal strain and can improve the absorption of lithium by the algal strain. The experimental results show that the algal strain can reduce the concentration of lithium from 0.1 mol / L to 0.03 mol / L. Since the use of the algal strain to absorb lithium has biological sustainability, this biosorption method is more environmentally friendly compared to traditional physical and chemical methods, reducing the generation of chemical waste.

[0074] Experiment 1

[0075] Using the above algal medium, add 50 mL of this medium to an open-type light shaking flask reactor with a total volume of 250 mL, and add 0.1 M of LiMn 2 O 4 solution. Use 5 M hydrochloric acid solution and 5 M sodium hydroxide solution to adjust the initial pH to 5, 7, and 8 respectively. The initial inoculation amount of Microcystis aeruginosa is 2%. After culturing for 7 days at 25 °C and 32 °C respectively, measure the concentration of Microcystis aeruginosa and the concentration of lithium. The results are shown in Table 1 below.

[0076] Table 1 Algal concentration and lithium concentration of Microcystis aeruginosa at different temperatures and pH values

[0077]

[0078]

[0079] As can be seen from Table 1, the experiments at 32 °C (Groups 4, 5, and 6) produced higher algal concentrations than the experiments at 25 °C (Groups 1, 2, and 3). This indicates that higher temperatures are beneficial for the growth of Microcystis aeruginosa.

[0080] The pH value also had an impact on the algal concentration and LiMn 2 O 4 concentration. At 25 °C, the highest algal concentration was observed at pH 8 (Group 3), while the lowest was at pH 5 (Group 1). At 32 °C, the highest algal concentration was still at pH 8 (Group 6), but the algal concentration at pH 7 (Group 5) also increased significantly.

[0081] LiMn 2 O 4 The LiMn 2 O 4 concentration decreased slightly over seven days, indicating that Microcystis aeruginosa absorbed some lithium. At 32 °C, the LiMn

[0082] concentration decreased most significantly at pH 8 (Group 6).

[0083] Thus, it can be seen that high temperatures and neutral to alkaline pH conditions are beneficial for the growth of Microcystis aeruginosa and also lead to higher lithium uptake.

[0084] The above experiments show that under suitable culture conditions, Microcystis aeruginosa can effectively absorb and enrich lithium in the solution. This provides a feasible way to use algal strains to adsorb lithium and solves the problem of lithium enrichment. Adding growth promoters (such as auxin and vitamins) can accelerate the growth of Microcystis aeruginosa and enable it to reach a high concentration in a shorter time. This helps to improve the efficiency of biological lithium adsorption. Suitable temperature and pH conditions are crucial for the growth of Microcystis aeruginosa and lithium uptake. By adjusting these factors, the growth and lithium uptake efficiency of Microcystis aeruginosa can be optimized.

[0085] Using algal strains to absorb lithium is biologically sustainable. Compared with traditional physical and chemical methods, this biological adsorption method is more environmentally friendly and reduces the generation of chemical waste. Algal strains can absorb lithium during their growth, which helps to combine microalgae with lithium battery production and thus improve the lithium recovery rate. Algal strains can grow and absorb lithium under different temperature and pH conditions. This means that this method can be applied under different environmental conditions and has flexibility. The biological adsorption method is generally relatively low in cost and the required materials are easily available, which helps to reduce production costs.Generally speaking, in this embodiment, by combining algal strains with growth promoters, suitable temperature, pH conditions, and growth time, efficient lithium element absorption can be achieved. This method has potential in terms of environmental protection, energy, and economy, providing a new biological method for lithium element enrichment and recovery.

[0086] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for absorbing lithium using an algal strain, characterized in that, it includes: Adding a specified concentration of auxin to an algal culture medium containing lithium element, and under the conditions of pH = 7 - 8 and temperature 32 ± 2 °C, the algal strain grows for a specified time to absorb the lithium element in the algal culture medium through the algal strain.

2. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the algal strain is Microcystis aeruginosa.

3. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the initial concentration of the lithium element is less than or equal to 0.1 mol / L.

4. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the algal culture medium includes: Sodium nitrate: 1.5 g / L; Potassium dihydrogen phosphate: 0.04 g / L; Potassium hydrogen phosphate: 0.075 g / L; Magnesium sulfate heptahydrate: 0.075 g / L; Calcium sulfate: 0.036 g / L; Ammonium ferric nitrate dodecahydrate: 0.006 g / L; Sodium carbonate: 0.02 g / L; Trace element solution: 1 mL / L.

5. The method for absorbing lithium using an algal strain according to claim 4, characterized in that, the trace element solution includes: Manganese chloride tetrahydrate: 0.4 g / L; Zinc sulfate heptahydrate: 0.1 g / L; Copper sulfate pentahydrate: 0.8 g / L; Sodium molybdate dihydrate: 0.1 g / L; Cobalt nitrate hexahydrate: 0.2 g / L.

6. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the specified concentration includes 0.1 - 10 mg / L.

7. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the auxin includes at least one of oskar, biotin, lipoic acid, and silicic acid.

8. The method for absorbing lithium using an algal strain according to claim 1, characterized in that, the algal culture medium further includes an organic carbon source; the organic carbon source includes glucose and / or agarose.

9. The method for absorbing lithium using an algal strain according to claim 8, characterized in that, the concentration of the organic carbon source is 0.01% - 0.1% wt.

10. The method for absorbing lithium using an algal strain according to claim 8, characterized in that, the specified time is 7 days.

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