Modified rare earth algistat, preparation method thereof and application of modified rare earth algistat in red tide and water bloom treatment

Abstract

The invention discloses a modified rare earth algistat, a preparation method thereof and application of the modified rare earth algistat in red tide and water bloom treatment. The modified rare earth algistat is prepared by mixing a 2-hydroxypyridine nitrogen oxide rare earth derivative, 8-hydroxyquinoline lanthanum, cellulose powder and second soluble rare earth salt. The composite material can release rare earth ions in water. The ions interact with negative charges on the surface of the algae through electrostatic adsorption, so that a bridging effect is formed, and the algae are quickly gathered and finally precipitated, so that effective flocculation is realized; wherein the 8-hydroxyquinoline lanthanum and the 2-hydroxypyridine nitrogen oxide rare earth compound have remarkable antibacterial and algae-inhibiting effects.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth compound applications, and particularly relates to a modified rare earth algaecide, a preparation method thereof, and application thereof in controlling red tides and algal blooms. Background Art

[0002] Algae play an important role in primary production in aquatic ecosystems, especially phytoplankton such as cyanobacteria, dinoflagellates, and diatoms, which play a key role in carbon cycling and primary productivity. For example, cyanobacteria can absorb carbon dioxide (CO2) and release oxygen (O2) through photosynthesis, which plays a positive role in maintaining the balance of aquatic ecosystems and supporting the growth of aquatic organisms. However, under the dual influences of eutrophication and climate change, harmful algal blooms dominated by cyanobacteria (such as Microcystis and Anabaena) often occur in freshwater bodies, while red tides are more common in marine or brackish water bodies, mainly caused by dinoflagellates (such as Alexandrium and Karenia) and diatoms.

[0003] Under specific environmental conditions, these harmful algae can rapidly erupt, forming dense algal blooms. These blooms not only cause hypoxia, foul odors, and reduced water clarity, but can also produce toxins, threatening aquatic life, human health, water safety, and the fishery economy, posing serious ecological and social problems. In recent years, harmful algal blooms in waters around the world have become more frequent, widespread, and multi-toxin-producing, making them a prominent aquatic environmental concern.

[0004] At present, the methods for controlling harmful algal blooms mainly include physical methods, biological methods, photocatalytic methods and chemical methods. Physical methods such as salvage, aeration and ultrasound have the problems of high cost, short-term effect and difficulty in large-scale application; biological methods (such as the introduction of algae-inhibiting microorganisms or aquatic plants) face challenges such as poor stability, ecological risks and long control cycles; photocatalytic methods rely on specific lighting conditions and their efficiency is significantly reduced in deeper or turbid water areas. In contrast, chemical algae removal has the advantages of rapid response, high treatment efficiency, strong applicability and low cost. It has been widely used, especially in emergency control and local outbreaks, and has become a common means of controlling red tides and freshwater cyanobacteria blooms. However, existing chemical algaecides generally have problems such as large dosage, strong toxic side effects, high ecological risks, and separation of algae removal and sedimentation. There is an urgent need to develop new, efficient, safe and environmentally friendly algae-inhibiting materials.

[0005] At present, most of these algaecides are active substances derived from seaweed epiphytic fungi, fungal-derived compounds obtained from deep-sea cold seep sediments, or a few organic compounds, such as diterpenoid compounds.

[0006] CN 1418825 A discloses a high-efficiency algae flocculant and a method for controlling red tides and algal blooms. This technical solution utilizes natural high-molecular-weight chitosan-modified clay to prepare a high-efficiency algae flocculant. At an addition level of 5 mg / L, after 8 hours of treatment, algae flocculation and sedimentation rates exceeding 95% by weight can be achieved. Literature reports that the use of microencapsulation technology, using sodium alginate and chitosan to encapsulate slow-release microparticles of linoleic acid, has demonstrated significant inhibitory effects against Microcystis aeruginosa. At an addition level of 1000 mg / L, inhibition rates can reach over 80% by weight after 20 days. Other studies have used copper sulfate, erythromycin thiocyanate, chlorine dioxide, potassium permanganate, and ozone as algaecides. However, these algaecides typically require application for at least 3 hours to achieve an inhibition rate exceeding 80% by weight. This means that these algaecides require high dosages or long application times, and environmental factors such as water flow may affect their effectiveness. Summary of the Invention

[0007] The present invention aims to overcome the defects of the prior art and provide a modified rare earth algaecide.

[0008] Another object of the present invention is to provide a method for preparing the modified rare earth algaecide.

[0009] Another object of the present invention is to provide the use of the modified rare earth algaecide in controlling red tides and algal blooms.

[0010] The technical solutions of the present invention are as follows:

[0011] A modified rare earth algaecide is prepared by mixing a 2-hydroxypyridine nitrogen oxide rare earth derivative, 8-hydroxyquinoline lanthanum, cellulose powder and a second soluble rare earth salt, wherein:

[0012] The content of the 2-hydroxypyridine nitrogen oxide rare earth derivative is 15-25wt%, which is prepared by reacting 2-hydroxypyridine nitrogen oxide, potassium hydroxide solution, and an ethanol solution of a first soluble rare earth salt in a mixed solvent of ethanol and deionized water, and the mass ratio of 2-hydroxypyridine nitrogen oxide to the first soluble rare earth salt is 330-340:350-440;

[0013] The content of 8-hydroxyquinoline lanthanum is 10-30wt%;

[0014] The content of cellulose powder is 35-45wt%, its Mn molecular weight is 30000-50000, and its purity is above 95%;

[0015] The content of the second soluble rare earth salt is 15-25 wt%.

[0016] In a preferred embodiment of the present invention, the first soluble rare earth salt is selected from samarium chloride, europium nitrate and lanthanum chloride.

[0017] Further preferably, the second soluble rare earth salt is selected from lanthanum chloride, cerium nitrate and gadolinium nitrate.

[0018] The preparation method of the modified rare earth algaecide comprises the following steps:

[0019] (1) Synthesis of 2-hydroxypyridine nitrogen oxide rare earth derivatives:

[0020] (2) Mixing 8-hydroxyquinoline lanthanum and the 2-hydroxypyridine nitrogen oxide rare earth derivative prepared in step (1):

[0021] (3) Add cellulose powder to the material obtained in step (2) and mix evenly.

[0022] (4) Add the second soluble rare earth salt to the material obtained in step (4) and mix them evenly to obtain the product.

[0023] In a preferred embodiment of the present invention, step (1) comprises: adding 2-hydroxypyridine nitrogen oxide to a mixed solvent of ethanol and deionized water and heating to dissolve, followed by dropwise addition of potassium hydroxide solution to control the pH value to 7-8; then dropwise addition of the first soluble rare earth salt ethanol solution within 2-3 hours, continuing the reaction for 25-35 minutes after the dropwise addition is completed, cooling and discharging, and then filtering, washing with deionized water, drying, crushing and sieving in sequence to obtain the product.

[0024] In a preferred embodiment of the present invention, step (2) comprises: mixing 8-hydroxyquinoline lanthanum and 2-hydroxypyridine nitrogen oxide rare earth derivatives, the mixing conditions being a temperature below 50°C, an air humidity below 85wt%, a rotation speed of 300r / min, and a time of 30min.

[0025] In a preferred embodiment of the present invention, the step (3) comprises: adding cellulose powder to the material obtained in step (2) and stirring and mixing them uniformly at a speed of 500 r / min for 15 minutes.

[0026] In a preferred embodiment of the present invention, step (4) comprises: adding the second soluble rare earth salt to the material obtained in step (3) and stirring and mixing them uniformly at a speed of 300 r / min for 20 minutes.

[0027] The application of the above-mentioned modified rare earth algaecides in the control of red tides and algal blooms.

[0028] A method for treating red tides and algal blooms in water comprises: mixing the modified rare earth algaecide with water to form a paste, and then applying the paste to the water body to be treated.

[0029] The beneficial effects of the present invention are:

[0030] 1. The modified rare earth algaecide of the present invention can release rare earth ions in water. These ions interact with the negative charges on the surface of algae through electrostatic adsorption, forming a bridging effect, causing the algae to rapidly aggregate and eventually precipitate, thereby achieving effective flocculation.

[0031] 2. This invention leverages the organic-inorganic properties of rare earth complexes to rapidly penetrate algal cell walls, inducing an emergency response mechanism in the algae. This leads to elevated reactive oxygen species (ROS) concentrations, damaging the cell walls and ultimately causing algal death. Furthermore, the rare earth complexes depolarize the algal cell membrane, reducing the electrochemical potential difference between the inside and outside of the cell membrane and inducing cell lysis.

[0032] 3. The 8-hydroxyquinoline lanthanum and 2-hydroxypyridinium nitrogen oxide rare earth compounds of the present invention have significant antibacterial and algae-inhibiting effects. After combining with algae, they can further destroy the living environment of algae. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a flow chart for preparing the modified rare earth algaecide of the present invention.

[0034] Figure 2 The figures show the inhibition rate of the modified rare earth algae inhibitor prepared in Example 2 of the present invention on Chlorella when different concentrations are added.

[0035] Figure 3 The figures show the inhibition rate of the modified rare earth algaecide prepared in Example 2 of the present invention on Alexander algae when different concentrations are added.

[0036] Figure 4 The figures show the inhibition rate of the modified rare earth algae inhibitor prepared in Example 2 of the present invention on Microcystis when different concentrations are added.

[0037] Figure 5 The figures show the inhibition rate of Karenia by adding the modified rare earth algae inhibitor prepared in Example 2 of the present invention at different concentrations.

[0038] Figure 6 This figure shows the comparative results of the inhibition rate of the modified rare earth algaecide prepared in Example 2 of the present invention and other comparative algaecides (the concentration of all the other algaecides is 2.0 mg / L except for the one without addition, and the one without addition means that no algaecide is added) on Chlorella.

[0039] Figure 7 This is a graph comparing the inhibition rates of the modified rare earth algaecide prepared in Example 2 of the present invention and other comparative algaecides (all with a concentration of 2.0 mg / L except for the one without addition, where no addition means no algaecide was added) on Karenia.

[0040] Figure 8The figures show the inhibition rate of Anabaena by adding the modified rare earth algae inhibitor prepared in Example 2 of the present invention at different concentrations.

[0041] Figure 9 The results show the inhibitory effect of the modified rare earth algaecide prepared in Example 2 of the present invention on Staphylococcus aureus.

[0042] Figure 10 The results show the inhibitory effect of the modified rare earth algaecide prepared in Example 2 of the present invention on Escherichia coli. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further illustrated and described below through specific implementation methods in conjunction with the accompanying drawings.

[0044] The preparation process of the following examples is as follows Figure 1 shown.

[0045] Example 1

[0046] (1) 333 g of 2-hydroxypyridine nitrogen oxide was added to a four-necked flask equipped with a condensation reflux device, and the flask was filled with a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water was 1:1). Heat to 60 ° C to slowly dissolve the 2-hydroxypyridine nitrogen oxide. Subsequently, a potassium hydroxide solution with a concentration of 2 wt% was added dropwise to control the pH value to 8. Then, 729.6 g of samarium chloride ethanol solution with a concentration of 50 wt% was added dropwise within 3 h. After the addition was completed, the reaction was continued for 30 min, then cooled and discharged. Afterwards, it was filtered, washed with deionized water 3 times, and finally dried at 140 ° C for 12 h to obtain a product with a yield of 75 wt%. Finally, the product was crushed and passed through an 800 mesh sieve to obtain a powder product (2-hydroxypyridine nitrogen oxide samarium compound) with a particle size D90 of 13 μm.

[0047] (2) Add 20 wt% of lanthanum 8-hydroxyquinoline and 20 wt% of samarium 2-hydroxypyridinium oxynitride into a mixer. During the mixing process, ensure that the temperature is below 50° C., the air humidity is below 85 wt%, the speed is 300 rpm, and the mixing time is 30 minutes.

[0048] (3) 45 wt% of cellulose powder (Mn molecular weight 30,000) was added to the material obtained in step (2), and stirring was continued at a speed of 500 r / min and a mixing time of 15 min.

[0049] (4) Add 15 wt% of soluble lanthanum chloride to the material obtained in step (3), maintain the rotation speed at 300 r / min, and the mixing time is 20 min to obtain a modified rare earth algaecide.

[0050] Example 2

[0051] (1) 333 g of 2-hydroxypyridine nitrogen oxide was added to a four-necked flask equipped with a condensation reflux device, and the flask was filled with a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water was 1:1). Heat to 60 ° C to slowly dissolve the 2-hydroxypyridine nitrogen oxide. Subsequently, a potassium hydroxide solution with a concentration of 2 wt% was added dropwise, and the pH value was controlled to 7. Then, 865.8 g of 50 wt% europium nitrate ethanol solution was added dropwise within 2 h. After the addition was completed, the reaction was continued for 30 min, then cooled and discharged. Afterwards, it was filtered, washed with deionized water 3 times, and finally dried at 140 ° C for 12 h to obtain a product with a yield of 75 wt%. Finally, the product was crushed and passed through an 800 mesh sieve to obtain a powder product (2-hydroxypyridine nitrogen oxide europium compound) with a particle size D90 of 10 μm.

[0052] (2) 10 wt% of lanthanum 8-hydroxyquinoline and 25 wt% of 2-hydroxypyridinium europium oxynitride were added to a mixer. During the mixing process, the temperature was maintained below 50° C., the air humidity was maintained below 85 wt%, the rotation speed was maintained at 300 rpm, and the mixing time was maintained at 30 minutes.

[0053] (3) Add 40 wt% of cellulose powder (Mn molecular weight 50,000) to the material obtained in step (2), and continue stirring at a speed of 500 r / min and a mixing time of 15 min.

[0054] (4) Add 25 wt% of soluble cerium nitrate to the material obtained in step (3), maintain the rotation speed at 300 r / min, and the mixing time is 20 min to obtain a modified rare earth algaecide.

[0055] The modified rare earth algaecide prepared in this example is mixed with water in a mass ratio of 60:40, and stirred into a paste using a blender. Then, it can be directly sprinkled into the water by hand or sprayed with a spraying device. The specific antibacterial and anti-algae effects of the modified rare earth algaecide prepared in this example are as follows: Figures 2 to 10 shown.

[0056] Example 3

[0057] (1) 333 g of 2-hydroxypyridine nitrogen oxide was added to a four-necked flask equipped with a condensation reflux device, and the flask was filled with a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water was 1:1). Heat to 60 ° C to slowly dissolve the 2-hydroxypyridine nitrogen oxide. Subsequently, a potassium hydroxide solution with a concentration of 2 wt% was added dropwise, and the pH value was controlled to 8. Then, 706.6 g of lanthanum chloride ethanol solution with a concentration of 50 wt% was added dropwise within 2.5 h. After the addition was completed, the reaction was continued for 30 min, then cooled and discharged. Afterwards, it was filtered, washed with deionized water 3 times, and finally dried at 140 ° C for 12 h to obtain a product with a yield of 75 wt%. Finally, the product was crushed and passed through an 800 mesh sieve to obtain a powder product (2-hydroxypyridine nitrogen oxide lanthanide) with a particle size D90 of 11 μm.

[0058] (2) 30 wt% of lanthanum 8-hydroxyquinoline and 15 wt% of lanthanum 2-hydroxypyridine oxynitride were added to a mixer. During the mixing process, the temperature was maintained below 50° C., the air humidity was maintained below 85 wt%, the rotation speed was maintained at 300 rpm, and the mixing time was maintained at 30 minutes.

[0059] (3) 35 wt% of cellulose powder (Mn molecular weight 30,000) was added to the material obtained in step (2), and stirring was continued at a speed of 500 r / min and a mixing time of 15 min.

[0060] (4) Add 20 wt% of soluble gadolinium nitrate to the material obtained in step (3), maintain the rotation speed at 300 r / min, and mix for 20 min to obtain a modified rare earth algaecide.

[0061] Comparative Example 1

[0062] (1) 333 g of 2-hydroxypyridine nitrogen oxide was added to a four-necked flask equipped with a condensation reflux device, and the flask was filled with a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water was 1:1). Heat to 60 ° C to slowly dissolve the 2-hydroxypyridine nitrogen oxide. Subsequently, a potassium hydroxide solution with a concentration of 2 wt% was added dropwise, and the pH value was controlled to 7. Then, 865.8 g of a 50 wt% europium nitrate ethanol solution was added dropwise within 2 h. After the addition was completed, the reaction was continued for 30 min, then cooled and discharged. Afterwards, it was filtered, washed with deionized water 3 times, and finally dried at 140 ° C for 12 h to obtain a product with a yield of 75 wt%. Finally, the product was crushed and passed through an 800 mesh sieve to obtain a powder product (2-hydroxypyridine nitrogen oxide europium compound) with a particle size D90 of 8 μm.

[0063] (2) Add 25 wt% of 2-hydroxypyridine europium oxynitride into a mixer. During the mixing process, ensure that the temperature is below 50°C, the air humidity is below 85 wt%, the rotation speed is 300 rpm, and the mixing time is 30 minutes.

[0064] (3) Add 50 wt% of cellulose powder (Mn molecular weight 50,000) to the material obtained in step (2), and continue stirring at a speed of 500 r / min and a mixing time of 15 min.

[0065] (4) 25 wt% of soluble cerium nitrate was added to the material obtained in step (3), the rotation speed was maintained at 300 r / min, and the mixing time was 20 min to obtain a comparative algaecide.

[0066] Comparative Example 2

[0067] (1) Add 35 wt% of lanthanum 8-hydroxyquinoline into a mixer. During the mixing process, ensure that the temperature is below 50°C, the air humidity is below 85 wt%, the speed is 300 rpm, and the mixing time is 30 minutes.

[0068] (2) Add 40 wt% of cellulose powder (Mn molecular weight 50,000) to the material obtained in step (1), and continue stirring at a speed of 500 r / min and a mixing time of 15 min.

[0069] (3) 25 wt% of soluble cerium nitrate was added to the material obtained in step (2), the rotation speed was maintained at 300 r / min, and the mixing time was 20 min to obtain a comparative algaecide.

[0070] Comparative Example 3

[0071] (1) 333 g of 2-hydroxypyridine nitrogen oxide was added to a four-necked flask equipped with a condensation reflux device, and the flask was filled with a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water was 1:1). Heat to 60 ° C to slowly dissolve the 2-hydroxypyridine nitrogen oxide. Subsequently, a potassium hydroxide solution with a concentration of 2 wt% was added dropwise, and the pH value was controlled to 7. Then, 865.8 g of a 50 wt% europium nitrate ethanol solution was added dropwise within 2 h. After the addition was completed, the reaction was continued for 30 min, then cooled and discharged. Afterwards, it was filtered, washed with deionized water 3 times, and finally dried at 140 ° C for 12 h to obtain a product with a yield of 75 wt%. Finally, the product was crushed and passed through an 800 mesh sieve to obtain a powder product (2-hydroxypyridine nitrogen oxide europium compound) with a particle size D90 of 14 μm.

[0072] (2) 10 wt% of lanthanum 8-hydroxyquinoline and 25 wt% of 2-hydroxypyridinium europium oxynitride were added to a mixer. During the mixing process, the temperature was maintained below 50° C., the air humidity was maintained below 85 wt%, the speed was maintained at 300 rpm, and the mixing time was 30 minutes.

[0073] (3) Add 25 wt% of soluble cerium nitrate to the material obtained in step (2), continue stirring, maintain the speed at 500 r / min, and the mixing time is 15 min to obtain a comparative algaecide.

[0074] Table 1 Algae inhibition test results of the algae inhibitors obtained in the examples and comparative examples (algae inhibitor concentration 2.0 mg / L, duration 2 h)

[0075]

[0076] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made within the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A modified rare earth algaecide, characterized in that: The invention is prepared by mixing 2-hydroxypyridine nitrogen oxide rare earth derivative, 8-hydroxyquinoline lanthanum, cellulose powder and a second soluble rare earth salt, wherein: The content of the 2-hydroxypyridine nitrogen oxide rare earth derivative is 15-25wt%, which is prepared by reacting 2-hydroxypyridine nitrogen oxide, potassium hydroxide solution, and an ethanol solution of a first soluble rare earth salt in a mixed solvent of ethanol and deionized water, and the mass ratio of 2-hydroxypyridine nitrogen oxide to the first soluble rare earth salt is 330-340:350-440; The content of 8-hydroxyquinoline lanthanum is 10-30wt%; The content of cellulose powder is 35-45wt%, its Mn molecular weight is 30000-50000, and its purity is above 95%; The content of the second soluble rare earth salt is 15-25 wt%.

2. The modified rare earth algaecide according to claim 1, characterized in that: The first soluble rare earth salt is selected from samarium chloride, europium nitrate and lanthanum chloride.

3. The modified rare earth algaecide according to claim 2, wherein: The second soluble rare earth salt is selected from lanthanum chloride, cerium nitrate and gadolinium nitrate.

4. The method for preparing a modified rare earth algaecide according to any one of claims 1 to 3, characterized in that: The steps include: (1) Synthesis of 2-hydroxypyridine nitrogen oxide rare earth derivatives: (2) Mixing 8-hydroxyquinoline lanthanum and the 2-hydroxypyridine nitrogen oxide rare earth derivative prepared in step (1): (3) Add cellulose powder to the material obtained in step (2) and mix evenly. (4) Add the second soluble rare earth salt to the material obtained in step (4) and mix them evenly to obtain the product.

5. The preparation method according to claim 4, wherein: The step (1) comprises: adding 2-hydroxypyridine nitrogen oxide to a mixed solvent of ethanol and deionized water, heating and dissolving, then dripping potassium hydroxide solution to control the pH value to 7-8; then dripping the ethanol solution of the first soluble rare earth salt within 2-3 hours, continuing the reaction for 25-35 minutes after the dripping is completed, cooling and discharging, and then filtering, washing with deionized water, drying, crushing and sieving in sequence to obtain the product.

6. The preparation method according to claim 4, wherein: The step (2) comprises: mixing 8-hydroxyquinoline lanthanum and 2-hydroxypyridine nitrogen oxide rare earth derivatives, wherein the mixing conditions are a temperature below 50° C., an air humidity below 85 wt %, a rotation speed of 300 r / min, and a mixing time of 30 min.

7. The preparation method according to claim 4, wherein: The step (3) comprises: adding cellulose powder to the material obtained in step (2) and stirring and mixing uniformly at a rotation speed of 500 r / min for 15 minutes.

8. The preparation method according to claim 4, wherein: The step (4) comprises: adding the second soluble rare earth salt to the material obtained in step (3) and stirring and mixing uniformly at a rotation speed of 300 r / min for 20 minutes.

9. Use of the modified rare earth algaecide according to any one of claims 1 to 3 in controlling red tides and algal blooms.

10. A method for controlling red tides and algal blooms in water, characterized by: include: The modified rare earth algaecide according to any one of claims 1 to 3 is mixed with water to form a paste, which is then applied to the water body to be treated.

Images