Modified rare earth algistat as well as preparation method and application thereof

Abstract

The invention discloses a modified rare earth algistat as well as a preparation method and application thereof. 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 present invention belongs to the technical field of the application of rare earth compounds, and particularly relates to a modified rare earth algicide and its preparation method and application. Background Art

[0002] The main function of cyanobacteria is to absorb carbon dioxide (CO 2 ) in the air and convert it into oxygen (O 2 ), providing important support for the growth of eukaryotes on the earth. However, cyanobacteria can grow and reproduce rapidly in some eutrophic water bodies, forming a layer of green and malodorous algal slurry, which is called harmful cyanobacterial bloom. The massive reproduction of cyanobacteria has led to dense and toxic bloom phenomena, which pose a serious threat to the entire ecosystem and cause damage to water bodies, animals and plants therein, human health, human quality of life, and economic development. In recent years, the high incidence, frequent occurrence, and outbreak of cyanobacterial blooms in aquatic ecosystems worldwide have become increasingly serious.

[0003] Currently, the methods for treating cyanobacterial blooms mainly include physical algae removal methods, biological algae removal methods, photocatalytic algae removal methods, and chemical algae removal methods. Physical algae removal technology is difficult to be widely applied in freshwater lakes due to defects such as high cost, low efficiency, and the inability to avoid the recurrence of cyanobacterial blooms in the coming year. The biological algae removal method is restricted in the promotion of its practical application due to reasons such as poor stability, long cycle, insufficient safety, and high economic cost. The photocatalytic algae removal technology uses materials or compounds to undergo oxidation-reduction reactions under light conditions to destroy algal cells. However, due to its dependence on light conditions, its application in deep water areas is restricted, resulting in reduced efficiency. In contrast, the chemical method has been widely applied due to its low cost, high efficiency, and good stability, and has become an important means for treating red tide blooms globally.

[0004] Currently, most of such algicides are active substances derived from epiphytic fungi of seaweeds, fungal-derived compounds obtained from deep-sea cold seep sediments, or a few organic compounds such as sesterterpenoid compounds, etc.

[0005] CN 1418825 A discloses a highly efficient algal flocculant and a method for treating red tides and water blooms. This technical solution uses natural polymer chitosan-modified clay to prepare a highly efficient algal flocculant. When the addition amount is 5 mg / L and after 8 h of treatment, the flocculation and sedimentation rate of algae can exceed 95 wt%. It is reported in the literature that by using microcapsule technology, slow-release microparticles of linoleic acid encapsulated by sodium alginate and chitosan show a significant inhibitory effect on Microcystis aeruginosa. At an addition amount of 1000 mg / L and after 20 days, the inhibition rate can reach more than 80 wt%. In addition, there are also studies using copper sulfate, erythromycin thiocyanate, chlorine dioxide, potassium permanganate, ozone, etc. as algal inhibitors. However, these algal inhibitors usually need to be applied for at least 3 h to achieve an algal inhibition rate of more than 80%. That is to say, this algal inhibitor requires a high input amount or a long application time during the application process, and environmental factors such as water flow may affect its actual effect. Summary of the Invention

[0006] The object of the present invention is to overcome the defects of the prior art and provide a modified rare earth algal inhibitor.

[0007] Another object of the present invention is to provide a preparation method of the above-mentioned modified rare earth algal inhibitor.

[0008] Still another object of the present invention is to provide the application of the above-mentioned modified rare earth algal inhibitor.

[0009] The technical solution of the present invention is as follows:

[0010] A modified rare earth algal inhibitor is prepared by mixing a 2-hydroxypyridine N-oxide rare earth derivative, lanthanum 8-hydroxyquinoline, cellulose powder, and a second soluble rare earth salt, wherein:

[0011] The content of the 2-hydroxypyridine N-oxide rare earth derivative is 15-25 wt%, and it is prepared by reacting 2-hydroxypyridine N-oxide, a potassium hydroxide solution, and an ethanol solution of a first soluble rare earth salt in a mixed solvent of ethanol and deionized water. The mass ratio of 2-hydroxypyridine N-oxide to the first soluble rare earth salt is 330-340:350-440;

[0012] The content of lanthanum 8-hydroxyquinoline is 10-30 wt%;

[0013] The content of cellulose powder is 35-45 wt%, its Mn molecular weight is 30000-50000, and its purity is more than 95%;

[0014] The content of the second soluble rare earth salt is 15-25 wt%.

[0015] In a preferred embodiment of the present invention, the first soluble rare earth salt is selected from samarium chloride, europium nitrate, and lanthanum chloride.

[0016] Further preferably, the second soluble rare earth salt is selected from lanthanum chloride, cerium nitrate and gadolinium nitrate.

[0017] The preparation method of the above-mentioned modified rare earth algaecide comprises the following steps:

[0018] (1) Synthesize rare earth derivatives of 2-hydroxypyridine N-oxide:

[0019] (2) Mix lanthanum 8-hydroxyquinolate and the rare earth derivatives of 2-hydroxypyridine N-oxide prepared in step (1).

[0020] (3) Add cellulose powder to the material obtained in step (2) and mix evenly.

[0021] (4) Add the second soluble rare earth salt to the material obtained in step (4) and mix evenly to obtain the product.

[0022] In a preferred embodiment of the present invention, step (1) includes: adding 2-hydroxypyridine N-oxide to a mixed solvent of ethanol and deionized water, heating and dissolving, then dropping a potassium hydroxide solution to control the pH value to 7-8; then dropping an ethanol solution of the first soluble rare earth salt within 2-3 h, continuing to react for 25-35 min after dropping, cooling and discharging, and then successively performing suction filtration, washing with deionized water, drying, crushing and sieving to obtain the product.

[0023] In a preferred embodiment of the present invention, step (2) includes: mixing lanthanum 8-hydroxyquinolate and the rare earth derivatives of 2-hydroxypyridine N-oxide, and the mixing conditions are that the temperature is lower than 50 °C, the air humidity is lower than 85 wt%, the rotation speed is 300 r / min, and the time is 30 min.

[0024] In a preferred embodiment of the present invention, step (3) includes: adding cellulose powder to the material obtained in step (2) and stirring and mixing evenly, with a rotation speed of 500 r / min and a time of 15 min.

[0025] In a preferred embodiment of the present invention, step (4) includes: adding the second soluble rare earth salt to the material obtained in step (3) and stirring and mixing evenly, with a rotation speed of 300 r / min and a time of 20 min.

[0026] The application of the above-mentioned modified rare earth algaecide in controlling red tides and water blooms.

[0027] A method for controlling red tides and water blooms in water, comprising: mixing the above-mentioned modified rare earth algaecide with water to form a paste, and then applying it to the water body to be treated.

[0028] The beneficial effects of the present invention are:

[0029] 1. The modified rare earth algicide 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, and then form a bridging effect, causing the algae to rapidly aggregate and finally precipitate, thereby achieving effective flocculation.

[0030] 2. Utilizing the organic-inorganic characteristics of rare earth complexes, the present invention can rapidly penetrate the cell walls of algae and induce an emergency response mechanism in the algae. This will lead to an increase in the concentration of reactive oxygen species, thereby causing damage to the cell walls and further triggering the death of the algae. In addition, the rare earth complexes will also cause depolarization of the algal cell membrane, promoting a decrease in the electrochemical potential difference inside and outside the cell membrane and causing cell lysis.

[0031] 3. Lanthanum 8-hydroxyquinoline and rare earth compounds of 2-hydroxypyridine N-oxide in the present invention have significant antibacterial and algicidal effects. After binding to the algae, they can further disrupt the living environment of the algae. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a process flow chart for the preparation of the modified rare earth algicide of the present invention.

[0033] Figure 2 It shows the inhibition rates of the modified rare earth algicide prepared in Example 2 of the present invention at different concentrations against Chlorella vulgaris.

[0034] Figure 3 It shows the inhibition rates of the modified rare earth algicide prepared in Example 2 of the present invention at different concentrations against Alexandrium.

[0035] Figure 4 It is a comparison result graph of the inhibition rates of the modified rare earth algicide prepared in Example 2 of the present invention and other comparative algicides (both at a concentration of 2.0 mg / L) against Chlorella vulgaris. DETAILED DESCRIPTION OF THE INVENTION

[0036] The technical solutions of the present invention will be further described and illustrated below through specific embodiments in conjunction with the drawings.

[0037] The preparation processes of the following examples are as Figure 1 shown.

[0038] Example 1

[0039] (1) Add 333 g of 2-hydroxypyridine N-oxide to a four-necked flask equipped with a condenser reflux device. The flask contains a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water is 1:1). Heat to 60 °C to slowly dissolve 2-hydroxypyridine N-oxide. Subsequently, add a potassium hydroxide solution with a concentration of 2 wt% and control the pH value to 8. Then, add 729.6 g of a samarium chloride ethanol solution with a concentration of 50 wt% dropwise within 3 h. After the addition is complete, continue the reaction for 30 min, then cool and discharge the material. After that, perform suction filtration, wash with deionized water 3 times, and finally dry at 140 °C for 12 h to obtain a product with a yield of 75 wt%. Finally, crush the product and pass it through an 800-mesh sieve to obtain a powder product (samarium 2-hydroxypyridine N-oxide) with a particle size D90 of 13 μm.

[0040] (2) Add 20 wt% of lanthanum 8-hydroxyquinoline and 20 wt% of samarium 2-hydroxypyridine N-oxide to 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 r / min, and the mixing time is 30 min.

[0041] (3) Add 45 wt% of cellulose powder (Mn molecular weight 30,000) to the material obtained in step (2), and continue stirring at a rotation speed of 500 r / min for 15 min.

[0042] (4) Add 15 wt% of soluble lanthanum chloride to the material obtained in step (3), maintain a rotation speed of 300 r / min, and mix for 20 min to obtain a modified rare earth algaecide.

[0043] Example 2

[0044] (1) Add 333 g of 2-hydroxypyridine N-oxide to a four-necked flask equipped with a condenser reflux device. The flask contains a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water is 1:1). Heat to 60 °C to slowly dissolve 2-hydroxypyridine N-oxide. Subsequently, add a potassium hydroxide solution with a concentration of 2 wt% and control the pH value to 7. Then, add 865.8 g of an europium nitrate ethanol solution with a concentration of 50 wt% dropwise within 2 h. After the addition is complete, continue the reaction for 30 min, then cool and discharge the material. After that, perform suction filtration, wash with deionized water 3 times, and finally dry at 140 °C for 12 h to obtain a product with a yield of 75 wt%. Finally, crush the product and pass it through an 800-mesh sieve to obtain a powder product (europium 2-hydroxypyridine N-oxide) with a particle size D90 of 10 μm.

[0045] (2) Add 10 wt% of lanthanum 8-hydroxyquinoline and 25 wt% of europium 2-hydroxypyridine N-oxide 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 r / min, and the mixing time is 30 min.

[0046] (3) Add 40 wt% of cellulose powder (Mn molecular weight 50000) into the material obtained in step (2), and continue stirring at a rotation speed of 500 r / min for 15 min.

[0047] (4) Add 25 wt% of soluble cerium nitrate into the material obtained in step (3), keep the rotation speed at 300 r / min, and the mixing time at 20 min to obtain the modified rare earth algaecide.

[0048] Mix the modified rare earth algaecide prepared in this example with water in a mass ratio of 60:40, use a stirrer to stir it into a paste, and then it can be directly spread into water by manual operation or sprayed by spraying equipment. The specific effects are as Figures 2 to 4 shown, where Figure 2 and Figure 3 are the alga flocculation effects of different algaecide addition amounts in this example, Figure 4 is the flocculation effect of the same concentration of different flocculants, and the control is without adding any algaecide.

[0049] Example 3

[0050] (1) Add 333 g of 2-hydroxypyridine N-oxide into a four-necked flask equipped with a condensing reflux device. The flask contains a mixed solvent of ethanol and deionized water (the mass ratio of ethanol to deionized water is 1:1). Heat to 60 °C to slowly dissolve 2-hydroxypyridine N-oxide. Subsequently, dropwise add a potassium hydroxide solution with a concentration of 2 wt% to control the pH value to 8. Then, dropwise add 706.6 g of lanthanum chloride ethanol solution with a concentration of 50 wt% within 2.5 h. After the dropping is completed, continue the reaction for 30 min, then cool and discharge. Then, perform suction filtration, wash 3 times with deionized water, and finally dry at 140 °C for 12 h to obtain a product with a yield of 75 wt%. Finally, crush the product and pass it through an 800-mesh sieve to obtain a powder product (lanthanum 2-hydroxypyridine N-oxide) with a particle size D90 of 11 μm.

[0051] (2) Add 30 wt% of lanthanum 8-hydroxyquinoline and 15 wt% of lanthanum 2-hydroxypyridine N-oxide 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 r / min, and the mixing time is 30 min.

[0052] (3) Add 35 wt% of cellulose powder (Mn molecular weight 30,000) to the material obtained in step (2), continue stirring at a speed of 500 r / min for 15 min.

[0053] (4) Add 20 wt% of soluble gadolinium nitrate to the material obtained in step (3), keep the speed at 300 r / min and mix for 20 min to obtain the modified rare earth algicide.

[0054] Comparative Example 1

[0055] (1) Add 333 g of 2-hydroxy pyridine N-oxide to a four-necked flask equipped with a condensing reflux device. The flask contains a mixed solvent of ethanol and deionized water (mass ratio of ethanol to deionized water is 1:1). Heat to 60 °C to slowly dissolve 2-hydroxy pyridine N-oxide. Subsequently, add a potassium hydroxide solution with a concentration of 2 wt% while controlling the pH value to 7. Then, add 865.8 g of europium nitrate ethanol solution with a concentration of 50 wt% dropwise within 2 h. After the addition is complete, continue the reaction for 30 min, then cool and discharge. Then, perform suction filtration, wash 3 times with deionized water, and finally dry at 140 °C for 12 h to obtain a product with a yield of 75 wt%. Finally, crush the product and pass it through an 800-mesh sieve to obtain a powder product (europium 2-hydroxy pyridine N-oxide) with a particle size D90 of 8 μm.

[0056] (2) Add 25 wt% of europium 2-hydroxy pyridine N-oxide to 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 r / min, and the mixing time is 30 min.

[0057] (3) Add 50 wt% of cellulose powder (Mn molecular weight 50,000) to the material obtained in step (2), continue stirring at a speed of 500 r / min for 15 min.

[0058] (4) Add 25 wt% of soluble cerium nitrate to the material obtained in step (3), keep the speed at 300 r / min and mix for 20 min to obtain the comparative algicide.

[0059] Comparative Example 2

[0060] (1) Add 35 wt% of lanthanum 8-hydroxyquinoline to 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 r / min, and the mixing time is 30 min.

[0061] (2) Add 40 wt% of cellulose powder (Mn molecular weight 50,000) to the material obtained in step (1), continue stirring at a rotation speed of 500 r / min for 15 min.

[0062] (3) Add 25 wt% of soluble cerium nitrate to the material obtained in step (2), keep the rotation speed at 300 r / min and the mixing time at 20 min to obtain the comparative algaecide.

[0063] Comparative Example 3

[0064] (1) Add 333 g of 2-hydroxypyridine N-oxide to a four-necked flask equipped with a condensing reflux device. The flask contains a mixed solvent of ethanol and deionized water (mass ratio of ethanol to deionized water is 1:1). Heat to 60 °C to slowly dissolve 2-hydroxypyridine N-oxide. Subsequently, add a potassium hydroxide solution with a concentration of 2 wt% while controlling the pH value to 7. Then, add 865.8 g of europium nitrate ethanol solution with a concentration of 50 wt% dropwise within 2 h. After the addition is complete, continue the reaction for 30 min, then cool and discharge the material. Then, perform suction filtration, wash 3 times with deionized water, and finally dry at 140 °C for 12 h to obtain a product with a yield of 75 wt%. Finally, crush the product and pass it through an 800-mesh sieve to obtain a powder product (europium 2-hydroxypyridine N-oxide) with a particle size D90 of 14 μm.

[0065] (2) Add 10 wt% of lanthanum 8-hydroxyquinoline and 25 wt% of europium 2-hydroxypyridine N-oxide to a mixer. During the mixing process, ensure that the temperature is below 50 °C, the air humidity is below 85 wt%, keep the rotation speed at 300 r / min, and the mixing time at 30 min.

[0066] (3) Add 25 wt% of soluble cerium nitrate to the material obtained in step (2), continue stirring, keep the rotation speed at 500 r / min, and the mixing time at 15 min to obtain the comparative algaecide.

[0067] Table 1 Algaecidal test results of the algaecides obtained in the examples and comparative examples (algaecide concentration 2.0 mg / L, duration 2 h)

[0068]

[0069]

[0070] The above is only the preferred embodiment of the present invention, and thus the scope of implementation of the present invention cannot be limited thereby. That is, equivalent changes and modifications made according to the scope of the present invention patent and the content of the specification should still fall within the scope covered by the present invention.

Claims

1. A modified rare earth algaecide, characterized in that: The method 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 the purity is more than 95%; The content of the second soluble rare earth salt is 15-25 wt %.

2. A 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. A modified rare earth algaecide according to claim 2, characterized in that: 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 obtained in step (1): (3) Add cellulose powder to the material obtained in step (2) and mix well. (4) Add the second soluble rare earth salt to the material obtained in step (4) and mix evenly to obtain the product.

5. The preparation method according to claim 4, characterized in that: 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, characterized in that: 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 85wt%, a rotation speed of 300 r / min, and a mixing time of 30 min.

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

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

10. A method for controlling red tide and algal bloom in water, characterized in that: 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.

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