An alga remover for emergency treatment of red tides and its preparation method

Abstract

The present invention relates to the technical field of emergency disposal of marine ecological disasters, and provides an algaecide for emergency disposal of red tides and a preparation method thereof. The algaecide comprises raw materials in the following parts by weight: 70-90 parts of clay, 10-40 parts of inorganic flocculant, and 0.02-1 part of organic flocculant; the organic flocculant comprises poly(dimethyldiallylammonium chloride) and polyvinyl alcohol; the mass ratio of poly(dimethyldiallylammonium chloride) to polyvinyl alcohol is 10:1-8. Through the above technical solution, the problem that the algaecide in the related technology has a low removal rate of red tide organisms is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of emergency disposal of marine ecological disasters. Specifically, it relates to an algaecide for emergency disposal of red tides and a preparation method thereof. Background Art

[0002] In recent years, under the dual pressures of human activities and climate change, red tides have occurred frequently, with the outbreak intensity, influence range, and duration increasing continuously. Harmful red tides can not only damage the marine ecosystem and affect the economic development of coastal areas, but even threaten human health and public safety, and have become one of the world's major marine disasters. The outbreak of red tides has a significant correlation with the aggravation of eutrophication in coastal waters. The presence of nutrients such as N and P provides a nutritional basis for the large-scale growth of red tide microalgae. Controlling the input of nutrients and regulating the output of nutrients can effectively reduce the frequency and intensity of red tide outbreaks.

[0003] Although the prevention of nutrients and exogenous organisms has been carried out at the source, reducing the frequency and affected area of red tides in coastal waters, the hazards brought about by some toxic and harmful red tides still exist. Therefore, once a threatening red tide disaster occurs, emergency disposal must be carried out immediately to achieve the purpose of disaster reduction and minimize the harm caused by red tides.

[0004] The natural clay sedimentation method has been widely used in the emergency disposal of red tides in countries such as Japan and South Korea since the 1980s and 1990s. Due to its wide source, low cost, and pollution-free characteristics, it is considered the most promising method for emergency disposal of red tides. However, the colloidal property of natural clay is relatively poor, and its efficiency in removing red tide algae organisms is relatively low. During the process of disposing of large-area red tide algae organisms, it is often necessary to apply a large amount of clay repeatedly for sedimentation, resulting in an increase in cost and the generation of a large amount of sludge. The low flocculation efficiency of natural clay has become the biggest bottleneck restricting the treatment of red tides by the clay sedimentation method. Therefore, improving the removal rate of red tide algae organisms is a problem that needs to be solved currently. Summary of the Invention

[0005] The present invention provides an algaecide for emergency disposal of red tides and a preparation method thereof, which solves the problem of low removal rate of red tide organisms by algaecides in related technologies.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides an algaecide for emergency disposal of red tides, comprising raw materials in the following parts by weight: 70 - 90 parts of clay, 10 - 40 parts of inorganic flocculant, and 0.02 - 1 part of organic flocculant; the organic flocculant includes poly(dimethyldiallylammonium chloride) and polyvinyl alcohol; the mass ratio of poly(dimethyldiallylammonium chloride) to polyvinyl alcohol is 10:1 - 8.

[0008] As a further technical solution, the mass ratio of the polydimethyldiallylammonium chloride to the polyvinyl alcohol is 10:2 to 5.

[0009] In the present invention, by defining the mass ratio of the polydimethyldiallylammonium chloride to the polyvinyl alcohol as 10:2 to 5, the removal rate of the algaecide is further improved.

[0010] As a further technical solution, the degree of alcoholysis of the polyvinyl alcohol is 87 to 94.5 mol%.

[0011] In the present invention, by defining the degree of alcoholysis of the polyvinyl alcohol as 87 to 94.5 mol%, the removal rate of the algaecide is further improved.

[0012] As a further technical solution, the clay is an organic composite clay, and the organic composite clay is obtained by compounding clay and 5-sodium sulfoisophthalate.

[0013] In the present invention, by obtaining the organic composite clay by compounding clay and 5-sodium sulfoisophthalate, the removal rate of the algaecide is further improved.

[0014] As a further technical solution, the preparation method of the organic composite clay includes the following steps: mixing 5-sodium sulfoisophthalate and clay in methanol and then drying to obtain the organic composite clay.

[0015] As a further technical solution, the mixing time is 1 to 2 h.

[0016] As a further technical solution, the addition amount of the 5-sodium sulfoisophthalate is 2% to 5% of the mass of the clay.

[0017] As a further technical solution, the clay includes one or more of kaolin, bentonite, coal gangue, and fly ash.

[0018] As a further technical solution, the inorganic flocculant includes one or two of aluminum-containing inorganic flocculants and iron-containing inorganic flocculants.

[0019] As a further technical solution, the inorganic flocculant is composed of the following components in parts by weight: 10 to 30 parts of aluminum-containing inorganic flocculant and 0 to 10 parts of iron-containing inorganic flocculant.

[0020] In the present invention, by adding aluminum-containing inorganic flocculants and iron-containing inorganic flocculants, good flocculation effects can be exerted within a relatively wide pH value range, and the adaptability to different types of source water quality is relatively strong.

[0021] As a further technical solution, the aluminum-containing inorganic flocculant includes one or more of polyaluminum chloride, polyaluminum sulfate, aluminum sulfate, and aluminum chloride.

[0022] As a further technical solution, the iron-containing inorganic flocculant includes one or two of polyferric sulfate and ferric chloride.

[0023] The present invention also provides a preparation method of an algaecide for emergency treatment of red tides, comprising the following steps:

[0024] S1. Dissolve the organic flocculant in a solvent to obtain a mixed solution, add clay to the mixed solution, stir, ripen, and dry to obtain a solid mixture;

[0025] S2. Compound the solid mixture with the inorganic flocculant to obtain the algaecide.

[0026] As a further technical solution, the mass ratio of the clay to the solvent is 1:2 to 5.

[0027] As a further technical solution, the solvent is water.

[0028] As a further technical solution, the ripening temperature is 20 to 45 °C, and the ripening time is 1 to 24 h.

[0029] As a further technical solution, in step S1, grinding is performed after drying.

[0030] As a further technical solution, in step S1, the drying temperature is 80 °C.

[0031] The working principle and beneficial effects of the present invention are as follows:

[0032] In the present invention, the algal remover uses clay as the main raw material, and an inorganic flocculant and an organic flocculant are added to modify the clay. After the clay is modified by the inorganic flocculant, the surface charge of the clay particles is reversed, changing from negative charge to positive charge, so that the electrostatic repulsion between the clay particles and algal cells is converted into electrostatic attraction, and then the adsorption electro-neutralization effect occurs, improving the efficiency of removing red tide organisms. The organic flocculant is an organic polymer with a long-chain structure, which can improve the bridging ability in the formation process of natural clay-red tide biological cell flocs, accelerate the sedimentation speed, and cause no secondary pollution. The organic flocculant includes poly(dimethyldiallylammonium chloride) and polyvinyl alcohol, both of which have the characteristics of low cost, environmental friendliness, safety and non-toxicity. Among them, poly(dimethyldiallylammonium chloride) can induce strong peroxidative stress, reduce the activity of red tide algae organisms, weaken the motility of red tide algae organisms, making them more easily captured and flocculated and sedimented by clay particles. Through inorganic-organic composite modification, on the basis of strong electro-neutralization ability, good adsorption bridging performance is obtained, enhancing the net trapping and sweeping effects of the modified clay on red tide algae biological cells, promoting the growth of flocs and then increasing the sedimentation speed of flocs, greatly improving the removal effect of red tide algae organisms, reducing the dosage of the remover, and significantly reducing the cost of red tide emergency disposal. Detailed implementation manners

[0033] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0034] In the following examples and comparative examples:

[0035] Poly(dimethyldiallylammonium chloride), CAS: 26062-79-3; polyvinyl alcohol of model PVA-217 with a degree of alcoholysis of 87-89 mol%; polyvinyl alcohol of model PVA-613 with a degree of alcoholysis of 92.5-94.5 mol%; polyvinyl alcohol of model PVA-CST with a degree of alcoholysis of 95.5-96.5 mol%; polyvinyl alcohol of model PVA-420H with a degree of alcoholysis of 79-81 mol%; kaolin with a particle size of 325 mesh; bentonite with a particle size of 325 mesh.

[0036] Example 1

[0037] A preparation method of an algal remover for red tide emergency disposal includes the following steps:

[0038] S1. Add 0.02 parts of organic flocculant to 140 parts of deionized water to obtain a mixed solution. Add 70 parts of kaolin to the mixed solution, mix evenly, then cure at 20 °C for 24 h, dry at 80 °C, and grind to obtain a solid mixture;

[0039] S2. Mix 10 parts of polyaluminum chloride and 10 parts of ferric chloride to obtain an inorganic flocculant;

[0040] S3. Compound the solid mixture and the inorganic flocculant to obtain an algae remover;

[0041] The organic flocculant is obtained by mixing poly(dimethyldiallylammonium chloride) and polyvinyl alcohol PVA-CST with a mass ratio of 10:8.

[0042] Example 2

[0043] A preparation method of an algae remover for red tide emergency disposal includes the following steps:

[0044] S1. Add 1 part of organic flocculant to 450 parts of deionized water to obtain a mixed solution. Add 90 parts of bentonite to the mixed solution, mix evenly, then cure at 45 °C for 1 h, dry at 80 °C, and grind to obtain a solid mixture;

[0045] S2. Use 30 parts of polyaluminum chloride as the inorganic flocculant;

[0046] S3. Compound the solid mixture and the inorganic flocculant to obtain an algae remover;

[0047] The organic flocculant is obtained by mixing poly(dimethyldiallylammonium chloride) and polyvinyl alcohol PVA-CST with a mass ratio of 10:8.

[0048] Example 3

[0049] This example is only different from Example 1 in that the mass ratio of poly(dimethyldiallylammonium chloride) and polyvinyl alcohol PVA-CST is 10:1.

[0050] Example 4

[0051] This example is only different from Example 1 in that the mass ratio of poly(dimethyldiallylammonium chloride) and polyvinyl alcohol PVA-CST is 2:1.

[0052] Example 5

[0053] This example is only different from Example 1 in that the mass ratio of poly(dimethyldiallylammonium chloride) and polyvinyl alcohol PVA-CST is 5:1.

[0054] Example 6

[0055] This example is only different from Example 5 in that polyvinyl alcohol PVA-CST is replaced with an equal amount of polyvinyl alcohol PVA-420H.

[0056] Example 7

[0057] This example is only different from Example 5 in that polyvinyl alcohol PVA-CST is replaced with an equal amount of polyvinyl alcohol PVA-217.

[0058] Example 8

[0059] This example is only different from Example 5 in that polyvinyl alcohol PVA-CST is replaced with an equal amount of polyvinyl alcohol PVA-613.

[0060] Example 9

[0061] This example is only different from Example 8 in that kaolin is replaced with an equal amount of modified kaolin; the preparation method of the modified kaolin includes the following steps: 40 g of kaolin and 0.8 g of 5-sodium sulfoisophthalate are mixed in 400 mL of methanol for 1 h, and then dried to obtain the modified kaolin.

[0062] Example 10

[0063] This example is only different from Example 8 in that kaolin is replaced with an equal amount of modified kaolin; the preparation method of the modified kaolin includes the following steps: 40 g of kaolin and 2 g of 5-sodium sulfoisophthalate are mixed in 400 mL of methanol for 2 h, and then dried to obtain the modified kaolin.

[0064] Comparative Example 1

[0065] This comparative example is only different from Example 1 in that polyvinyl alcohol PVA-CST is replaced with an equal amount of polydimethyldiallylammonium chloride.

[0066] Comparative Example 2

[0067] This comparative example is only different from Example 1 in that polydimethyldiallylammonium chloride is replaced with an equal amount of polyvinyl alcohol PVA-CST.

[0068] Comparative Example 3

[0069] A preparation method of an algaecide for red tide emergency disposal includes the following steps:

[0070] S1. Mix 10 parts of polyaluminum chloride and 10 parts of ferric chloride to obtain an inorganic flocculant;

[0071] S2. Compound 70 parts of kaolin and the inorganic flocculant to obtain the algaecide.

[0072] Comparative Example 4

[0073] A preparation method of an alga remover for red tide emergency disposal, comprising the following steps:

[0074] Add 0.02 parts of an organic flocculant to 350 parts of deionized water to obtain a mixed solution. After adding 70 parts of kaolin to the mixed solution and mixing evenly, it is aged, dried at 80 °C, and ground to obtain the alga remover.

[0075] Experimental Example 1

[0076] Prepare the remover suspension: Add 1 g of the remover to 20 mL of seawater to prepare a 50 g / L remover suspension;

[0077] Red tide organism removal rate: Take 50 mL of red tide organism algal solution (Scrippsiella trochoidea, Prorocentrum minimum, with an algal cell density reaching 10 7 cells / L) in the exponential growth phase and add it to a 50 mL colorimetric tube. Use a pipette to add 1 mL of the remover suspension, invert and mix well, and then let it stand for 2 h under the culture conditions (set a blank control group and add the same volume of seawater); Take the supernatant of the above colorimetric tube, fix it with Lugol's reagent, shake well, use a pipette to extract 0.5 mL, place it under a microscope for algal cell counting, extract 3 times for each sample, count separately and take the average value; And calculate the red tide organism removal rate according to the following formula:

[0078] Red tide organism removal rate = [1 - (experimental group algal cell density / control group algal cell density)] × 100%.

[0079] Red tide organism laboratory culture method:

[0080] Step 1: Take natural seawater, filter it with a 0.45 μm fiber filter membrane and place it in a conical flask, seal it with a sealing film and tie it tightly with a rubber band;

[0081] Step 2: Autoclave the above conical flask and the pipette tips required for inoculation at 121 °C for 20 min. After sterilization, transfer them to the ultra-clean bench in the sterile room;

[0082] Step 3: Use a pipette to suck the f / 2 medium concentrate and transfer it to the sterilized seawater, and shake well;

[0083] Step 4: Inoculate the algae species to be cultured (Scrippsiella trochoidea, Prorocentrum minimum) into the above conical flask, place it in an incubator for culture, with a temperature of 20 ± 1 °C, a light-dark ratio of 12 h:12 h, and manually shake the conical flask at least three times a day.

[0084] The test results are shown in Table 1.

[0085] Table 1 Test results of the removal rate of the alga remover

[0086]

[0087] Compared with Comparative Examples 1 to 4, the removal rates of the algal removers prepared in Examples 1 to 10 for *Scrippsiella trochoidea* and *Prorocentrum minimum* are higher than those of Comparative Examples 1 to 4, indicating that the organic composite clay obtained by compounding clay and 5-sulfosalicylic acid, when compounded with inorganic and organic flocculants, where the organic flocculant is composed of poly(dimethyldiallylammonium chloride) and polyvinyl alcohol, can improve the removal rate of the algal remover for red tide organisms.

[0088] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An algae remover for emergency treatment of red tide, characterized in that: The raw materials include the following components in parts by weight: 70-90 parts of clay, 10-40 parts of inorganic flocculant, and 0.02-1 part of organic flocculant; the organic flocculant includes polydimethyldiallyl ammonium chloride and polyvinyl alcohol; the alcoholysis degree of the polyvinyl alcohol is 87-94.5 mol%; the clay is an organic composite clay, which is obtained by compounding clay and sodium 5-sulfoisophthalic acid; the addition amount of sodium 5-sulfoisophthalic acid is 2%-5% of the mass of the clay; the mass ratio of the polydimethyldiallyl ammonium chloride to the polyvinyl alcohol is 5:

1.

2. The algae remover for emergency treatment of red tide according to claim 1, characterized in that: The inorganic flocculant is composed of the following components in parts by weight: 10 to 30 parts of an aluminum-containing inorganic flocculant and 0 to 10 parts of an iron-containing inorganic flocculant.

3. The algae remover for emergency treatment of red tide according to claim 2, characterized in that: The aluminum-containing inorganic flocculant includes one or more of polyaluminum chloride, polyaluminum sulfate, aluminum sulfate, and aluminum chloride.

4. The algae remover for emergency treatment of red tide according to claim 2, characterized in that: The iron-containing inorganic flocculant includes one or both of polymerized ferric sulfate and ferric chloride.

5. The algae remover for emergency treatment of red tide according to claim 1, characterized in that: The clay includes one or more of kaolin, bentonite, coal gangue and fly ash.

6. The method for preparing an algae remover for emergency treatment of red tide according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, dissolving an organic flocculant in a solvent to obtain a mixed solution, adding clay to the mixed solution, stirring, aging, and drying to obtain a solid mixture; S2. Compounding the solid mixture and an inorganic flocculant to obtain an algae remover.

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