Floating type aerogel algal removal catalyst, preparation method and floating type algal removal agent

Abstract

The application discloses a floating type aerogel algae-removing catalyst, a preparation method and a floating type algae-removing agent. The floating type algae-removing catalyst takes guar gum as a carrier matrix and is loaded with single metal atoms. The single metal atoms include one of copper atoms, iron atoms, cobalt atoms and manganese atoms. The single metal atoms can catalyze decomposition of persulfate in the floating type algae-removing agent to form a large number of active oxygen free radicals, which further attack the surface morphology and internal tissue structure of algal cells, leading to cell integrity being destroyed and cell activity greatly decreasing, so that the algae-removing effect is achieved. Meanwhile, the single metal atoms can form a cross-linking network architecture between the single metal atoms and the guar gum through a coupling reaction to form an aerogel, so that the algae-removing agent can stably float on the water surface, can efficiently remove algae and is beneficial to recycling and utilization in the later period.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of algae-removing agents, in particular to a floating aerogel algae-removing catalyst, a preparation method and a floating algae-removing agent. BACKGROUND

[0002] In recent years, with the discharge of sewage and the abuse of agricultural fertilizers, the nitrogen and phosphorus content in water bodies has increased, causing eutrophication of water bodies, which in turn causes algae to grow and reproduce wildly in such water bodies, affecting the survival of fish, shrimp, shellfish and other aquatic organisms in the water bodies and the safety of human drinking water, and destroying the biodiversity in the water environment. Therefore, finding a practical algae-removing method has become a problem that needs to be solved in the field of algae pollution control.

[0003] Among the currently used algae-removing methods, advanced oxidation method has attracted more and more attention due to its high algae-removing efficiency and simple use method. The method mainly destroys the cell membrane of algae cells by generating a large number of active groups such as hydroxyl radicals to decompose organic pollutants that are difficult to degrade. In this process, catalyst activation is needed to generate corresponding active oxygen species. Transition metal ions have high catalytic performance and can provide a rapid reaction process, but it is difficult to recover metal ions in water after treatment by transition metal ion activation method, which leads to a large amount of metal ions existing in water and causing secondary pollution, posing a potential threat to human health. Although the transition metal oxide activation method solves the problem of recovery, it still has the problems of easy agglomeration of metal oxides and risk of dissolution of metal ions, which can reduce the catalytic activity. SUMMARY

[0004] To solve the problems of difficult recovery of catalyst and secondary pollution of water body caused by free metal ions in the application process of advanced oxidation method, the present application provides a floating aerogel algae-removing catalyst, a preparation method and a floating algae-removing agent.

[0005] In a first aspect, the present application provides a floating aerogel algae-removing catalyst, wherein the floating algae-removing catalyst takes guar gum as a carrier matrix and is loaded with single metal atoms; the single metal atoms include one of copper atoms, iron atoms, cobalt atoms and manganese atoms.

[0006] By adopting the technical scheme, the single metal atom has good catalytic activation effect on persulfate, can activate and decompose persulfate in the process of algae removal, and generate oxidation substances mainly in the form of singlet oxygen, and a large amount of hydroxyl radicals, sulfate radicals and superoxide radicals, wherein the oxidation ability of the singlet oxygen can promote the inactivation of the algae cells, cause damage to the cell membrane system of the algae cells, and the large amount of oxidation groups such as the hydroxyl radicals and the sulfate radicals can degrade algae toxins and algae organic matter, and can also change the surface properties of the algae cells, promote the instability of the algae, and achieve the effect of algae removal.

[0007] In the present application, the single metal atom is also used as a carrier matrix of guar gum and is loaded on the guar gum. On the one hand, the guar gum is a high-molecular-mass polysaccharide containing a large amount of hydroxyl groups, and the metal ions can couple with the vicinal hydroxyl groups on different molecular chains of the guar gum to crosslink different guar gum molecules, form a new spatial network structure, obtain a branched and complex gel system, and thus the single metal atom is stably anchored in the three-dimensional crosslinked network formed by the guar gum, which is beneficial to the further recovery of the catalyst after the algae removal treatment. In addition, the single metal atom is closely combined with the guar gum, and the crosslinked network formed thereby can prevent the metal atom from being dissolved in the process of algae removal, thereby reducing the secondary pollution of free metal ions to the water body. At the same time, since the single metal atom is anchored in the guar gum and is less affected by the pH value, anions including chloride ions and phosphate ions, and humus in the water body, the obtained algae removal catalyst and algae removal agent can be applied to the removal of algae in water bodies in different environments. Specifically, the obtained algae removal catalyst and algae removal agent have good algae removal performance in water bodies with a pH value of 3-9.

[0008] On the other hand, the aerogel structure formed between the single metal atom and the guar gum can also enable the obtained algae removal catalyst to stably float on the water surface and not to be settled for a long time. By taking advantage of the fact that algae usually float on the water surface, the obtained floating aerogel algae removal catalyst can efficiently remove algae, and is beneficial to the recovery of the algae removal catalyst in the later stage.

[0009] Finally, the large amount of hydroxyl groups contained in the guar gum as electron donor groups can promote the cyclic transformation between the valence states of the metal atom and activate persulfate, form a coordinated action with the single metal atom, enhance the catalytic activation effect of the obtained algae removal catalyst, and improve the efficiency of algae removal, thereby having excellent removal effect on algae in the water body.

[0010] Preferably, the floating aerogel algae removal catalyst comprises the following raw materials by mass fraction:

[0011] Guar gum 1 part;

[0012] Metal salt 0.15-0.3 parts;

[0013] Polyamine 1-3 parts.

[0014] Preferably, the metal salt comprises one of copper nitrate, manganese nitrate, cobalt nitrate, iron nitrate, copper sulfate, iron sulfate, manganese sulfate monohydrate, copper chloride, iron chloride.

[0015] Preferably, the polyamine comprises one or a combination of melamine and dicyandiamide.

[0016] Preferably, the molecular weight of the guar gum is 1.0 x 10 5 ~ 2.0 x 10 6 .

[0017] By adopting the technical scheme, the floating aerogel algae-removal catalyst further adds polyamine. Polyamine is a nitrogen-containing heterocyclic organic compound containing a large number of amine groups. In the process of forming a cross-linked structure between metal ions and guar gum, the amine groups contained in polyamine can uniformly disperse metal atoms in the solution, reduce the agglomeration between single metal atoms, and after the combination of polyamine and guar gum, carbon nitride structures can be introduced into the aerogel algae-removal catalyst, which can further ensure the stability of single metal atoms and their distribution. Meanwhile, N atoms can also adjust the electronic structure and charge density between metal atoms and guar gum, so that the single metal atoms in the finally obtained aerogel algae-removal catalyst can be uniformly distributed on the guar gum, thereby improving the catalytic efficiency of the catalyst.

[0018] In addition, the amino groups contained in polyamine can act as electron donor groups to jointly accelerate the cyclic transformation between the valence states of single metal atoms with the hydroxyl groups contained in guar gum, improve the formation of singlet oxygen and other active oxygen species, and the polar groups contained in polyamine and guar gum can also reduce the surface potential of algal cells, thereby causing the agglomeration and sedimentation of algal cells, and enhancing the algae-removal capacity of the aerogel algae-removal catalyst.

[0019] In a second aspect, the application provides a preparation method of a floating aerogel algae-removal catalyst, which comprises the following steps:

[0020] S1. Adding a metal salt to deionized water and stirring to dissolve to obtain a metal ion aqueous solution;

[0021] S2. Adding polyamine and guar gum to the metal ion aqueous solution obtained in S1, stirring to dissolve at a temperature of 30-35℃; after dissolving, standing at room temperature for 45-50h to obtain a metal ion cross-linked hydrogel;

[0022] S3. Freeze-drying the metal ion cross-linked hydrogel for 70-72h to obtain a metal ion cross-linked aerogel;

[0023] S4. Carbonizing the metal ion cross-linked aerogel under a nitrogen atmosphere at a temperature of 700-720 DEG C for 2-3 hours;

[0024] S5. Acid soaking and washing the carbonized metal ion cross-linked aerogel several times until the metal ion cross-linked aerogel is neutral, and then drying to obtain the single-atom-loaded floating aerogel algal removal catalyst.

[0025] By adding the metal salt to the deionized water, the metal salt is hydrolyzed to form metal ions, which then couple with the hydroxyl groups contained in the guar gum to gradually form a cross-linked network structure, obtaining a gel system with a large branch and complex structure, and the metal atoms are also anchored in the three-dimensional cross-linked network structure. At this time, the poly cyanamide adjusts the electronic structure and charge density between the metal ions and the guar gum, allowing the metal ions to be uniformly dispersed in and loaded on the guar gum. On the other hand, the poly cyanamide is compounded with the guar gum, introducing a new carbon nitride structure into the aerogel algal removal catalyst, which can significantly improve the stability of the aerogel algal removal catalyst, reduce the influence of external water flow, and improve the mechanical properties of the aerogel algal removal catalyst.

[0026] The obtained metal ion cross-linked hydrogel is subjected to freeze-drying treatment to better maintain the gel structure and activity. Further carbonization treatment not only enhances the compounding between poly cyanamide and guar gum, allowing poly cyanamide to be closely combined with guar gum to promote the algal removal effect, but also further maintains the three-dimensional network structure of the obtained aerogel from being destroyed. Adjusting the pores of the aerogel algal removal catalyst through carbonization treatment can improve the specific surface area of the catalyst and the efficiency of chemical reactions, prolong the contact time between the substrate and the catalyst, and thus improve the catalytic activity of the catalyst and the algal removal efficiency.

[0027] In a third aspect, the application provides a floating algal removal agent, wherein the raw materials of the floating algal removal agent include the single-atom-loaded floating aerogel algal removal catalyst of any one of claims 1-5 and a persulfate salt.

[0028] Preferably, the mass ratio of the floating aerogel algal removal catalyst to the persulfate salt is (0.6-0.8):(0.1-0.15).

[0029] Preferably, the persulfate salt includes one or a combination of several of potassium monopersulfate, potassium persulfate, and sodium monopersulfate.

[0030] Preferably, the dosage of the floating algal removal agent is 0.2-1 g / L.

[0031] By adopting the above technical scheme, under the mass ratio and the adding amount in the application, the floating aerogel algae-removal catalyst can effectively catalyze and activate persulfate at room temperature, an electron transfer occurs between the single metal atom contained in the catalyst and the persulfate, a large amount of active oxygen species is generated, these active oxygen species all have high oxidation potential, can attack the surface morphology and internal tissue structure of the algae cells, cause the cell integrity to be destroyed and the activity of the cells to greatly decrease, and the extracellular organic matter released in the cell rupture can also be rapidly degraded by the active oxygen free radicals, after the algae-removal treatment is completed, the aerogel algae-removal catalyst is floating on the water surface, is convenient to recycle, and the metal atom contained therein will not be left in the water body to cause secondary pollution to the water body.

[0032] Preferably, the use process of the floating algae-removal agent comprises: adding the floating algae-removal agent into the water body to mix; the floating algae-removal agent forms a floating state on the surface of the water body to perform the algae-removal work.

[0033] More preferably, the floating algae-removal agent is added into the water body to mix, and the mixing mode comprises one of the following: adding the floating algae-removal agent into the water body to stir and mix to form a suspension system, adding the floating algae-removal agent into deionized water to pre-mix and then adding the pre-mixed solution into the water body to mix, and loading the floating algae-removal agent into an algae-removal reaction device to add into the water body to mix.

[0034] In summary, the application has the following beneficial effects:

[0035] 1. The floating aerogel algae-removal catalyst in the application takes guar gum as a carrier matrix, and a single metal atom is loaded thereon, the metal ion can form a crosslinked network architecture through a coupling reaction with the guar gum, and poly cyanamide is also added in the preparation process, the amine groups contained in the poly cyanamide can accelerate the transformation between the valence states of the single metal atom and the hydroxyl groups contained in the guar gum, enhance the catalytic efficiency of the catalyst, the addition of the poly cyanamide can also make the metal ion uniformly dispersed on the guar gum, the introduction of the carbon nitride structure also increases the stability of the aerogel structure, the metal atom will not be easily dissolved out to cause secondary pollution, and the floating aerogel algae-removal catalyst obtained through the above method can stably float on the water surface, can efficiently remove the algae, and is beneficial to the recycling of the algae-removal catalyst in the later period.

[0036] 2. The floating algae-removal agent in the application comprises the floating aerogel algae-removal catalyst and persulfate, the single metal atom contained in the catalyst can catalyze and decompose the persulfate to form a large amount of active oxygen species, the active oxygen species can attack the surface morphology and internal tissue structure of the algae cells, cause the cell integrity to be destroyed and the activity of the cells to greatly decrease, and thus achieve the algae-removal effect, and the floating aerogel structure is also beneficial to the recycling and will not cause secondary pollution to the water body. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a live picture of the floating situation of the algae-removal agent before and after 10 days of the floating performance test of Example 2-1. DETAILED DESCRIPTION

[0038] Example 1

[0039] Example 1-1, a floating type aerogel algae-removal catalyst, is prepared according to the following method:

[0040] S1. 0.2 g of copper nitrate is added to 100 ml of deionized water to obtain a copper ion aqueous solution by stirring and dissolving;

[0041] S2. 1 g of melamine and 1 g of guar gum (the relative average molecular mass of the guar gum is 1.0 x 10 6 ) are added to the copper ion aqueous solution obtained in the step S1, the temperature is raised to 35℃, and stirring and dissolving are performed; after dissolving, the solution is left to stand at room temperature for 48 h to obtain a copper ion crosslinked hydrogel;

[0042] S3. The copper ion crosslinked hydrogel is freeze-dried for 72 h to obtain a copper ion crosslinked aerogel;

[0043] S4. The copper ion crosslinked aerogel is subjected to carbonization treatment under a nitrogen atmosphere, the carbonization temperature is 700℃, and the carbonization time is 2 h; S5. The copper ion crosslinked aerogel after the carbonization treatment is subjected to several times of acid immersion and cleaning (the acid immersion solution is a nitric acid solution with a mass fraction of 2%), until the copper ion crosslinked aerogel is neutral; then the copper ion crosslinked aerogel is dried in a vacuum drying oven at 60℃ for 24 h to obtain a floating type aerogel algae-removal catalyst loaded with copper atoms.

[0044] Example 1-2, a floating type aerogel algae-removal catalyst, is different from Example 1-1 only in that the amount of copper nitrate added is 0.15 g.

[0045] Example 1-3, a floating type aerogel algae-removal catalyst, is different from Example 1-1 only in that the amount of copper nitrate added is 0.3 g.

[0046] Example 1-4, a floating type aerogel algae-removal catalyst, is different from Example 1-1 only in that the amount of melamine added is 2 g.

[0047] Example 1-5, a floating type aerogel algae-removal catalyst, is different from Example 1-1 only in that the amount of melamine added is 3 g.

[0048] Example 1-6, a floating type aerogel algae-removal catalyst, is different from Example 1-1 only in that an equal amount of manganese nitrate is used to replace copper nitrate.

[0049] Example 1-7, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the copper nitrate is replaced with an equal amount of ferric sulfate.

[0050] Example 1-8, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the melamine is replaced with an equal amount of dicyandiamide.

[0051] Example 1-9, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the amount of copper nitrate added is 0.1 g.

[0052] Example 1-10, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the amount of copper nitrate added is 0.4 g.

[0053] Example 1-11, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the amount of melamine added is 0.5 g.

[0054] Example 1-12, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that the amount of melamine added is 4 g.

[0055] Example 1-13, a floating type aerogel algae-removal catalyst, differs from Example 1-1 only in that no melamine is added in the S2 step.

[0056] Example 2

[0057] Example 2-1, a floating type algae-removal agent, is prepared according to the following method:

[0058] The floating type aerogel algae-removal catalyst prepared in Example 1-1 and potassium peroxodisulfate are mixed in a mass ratio of 0.6:0.125 to obtain a floating type algae-removal agent.

[0059] The dosage of the algae-removal agent is 0.8 g / L.

[0060] Example 2-2, a floating type algae-removal agent, differs from Example 2-1 only in that the mass ratio of the floating type aerogel algae-removal catalyst prepared in Example 1-1 to potassium peroxodisulfate is 0.8:0.125.

[0061] Example 2-3, a floating type algae-removal agent, differs from Example 2-1 only in that the mass ratio of the floating type aerogel algae-removal catalyst prepared in Example 1-1 to potassium peroxodisulfate is 0.6:0.1.

[0062] Example 2-4, a floating type algae-removal agent, differs from Example 2-1 only in that the mass ratio of the floating type aerogel algae-removal catalyst prepared in Example 1-1 to potassium peroxodisulfate is 0.6:0.15.

[0063] Example 2-5, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-2 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0064] Example 2-6, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-3 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0065] Example 2-7, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-4 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0066] Example 2-8, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-5 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0067] Example 2-9, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-6 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0068] Example 2-10, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-7 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0069] Example 2-11, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-8 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0070] Example 2-12, a floating algaecide, differs from Example 2-1 only in that the dosage of the floating algaecide during use is 0.2 g / L.

[0071] Example 2-13, a floating algaecide, differs from Example 2-1 only in that the dosage of the floating algaecide during use is 1 g / L.

[0072] Example 2-14, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecidal catalyst prepared in Example 1-9 is used in place of the floating aerogel algaecidal catalyst prepared in Example 1-1.

[0073] Example 2-15, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecide catalyst prepared in Example 1-1 is replaced with an equal amount of the floating aerogel algaecide catalyst prepared in Example 1-10.

[0074] Example 2-16, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecide catalyst prepared in Example 1-1 is replaced with an equal amount of the floating aerogel algaecide catalyst prepared in Example 1-11.

[0075] Example 2-17, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecide catalyst prepared in Example 1-1 is replaced with an equal amount of the floating aerogel algaecide catalyst prepared in Example 1-12.

[0076] Example 2-18, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecide catalyst prepared in Example 1-1 is replaced with an equal amount of the floating aerogel algaecide catalyst prepared in Example 1-13.

[0077] Example 2-19, a floating algaecide, differs from Example 2-1 only in that the mass ratio of the floating aerogel algaecide catalyst prepared in Example 1-1 to potassium monopersulfate is 0.9:0.125.

[0078] Example 2-20, a floating algaecide, differs from Example 2-1 only in that the mass ratio of the floating aerogel algaecide catalyst prepared in Example 1-1 to potassium monopersulfate is 0.4:0.125.

[0079] Comparative Example

[0080] Comparative Example 2-1, a floating algaecide, differs from Example 2-1 only in that the floating aerogel algaecide catalyst prepared in Example 2-1 is replaced with an equal amount of zero-valent copper.

[0081] Performance detection test

[0082] 1. Algaecide test:

[0083] The algaecide effect of the floating algaecide obtained in Examples 2 and Comparative Examples was compared in the laboratory by simulating the situation of water body being polluted by algae. The performance of the floating aerogel algaecide catalyst prepared in Example 1 can be characterized by the performance of the floating algaecide.

[0084] The specific algaecide test method is as follows:

[0085] Step one: Take 100 ml of Microcystis aeruginosa algal liquid (1 x 106 ml), centrifuged at 4000 rpm to obtain an algae cake, resuspended with ultrapure water, and adjusted to pH 7 for standby;

[0086] Step two: the floating type algae-removal agent obtained in the examples and comparative examples was added into the algae-containing water body according to the corresponding addition ratio, and the algae-containing water body was stirred at a stirring speed of 250 rpm for 5 min, and then stirred at a stirring speed of 40 rpm for 5 min.

[0087] Step three: after standing for 30 min, the removal rates of algae cells and chlorophyll in the water body were tested. The test results are shown in Table 1.

[0088] Step four: after the floating type algae-removal agent in step three was recovered, the above steps were repeated 5 times, and the removal rate of algae cells in the water body after 5 cycles of recovery-removal was tested. The test results are shown in Table 1.

[0089] In addition, two algae-removal tests were newly added to change the mixing method in step two. Specifically:

[0090] (1) The floating type algae-removal agent prepared in Example 2-1 was added into the algae-containing water body according to the corresponding addition ratio, and the algae-containing water body was stirred at a stirring speed of 150 rpm for 10 min.

[0091] (2) The floating type algae-removal agent prepared in Example 2-1 was first added into deionized water for pre-mixing, and then the pre-mixed solution was added into the algae-containing water body, and the algae-containing water body was stirred at a stirring speed of 40 rpm for 5 min.

[0092] After the above mixing methods, the test in step three was carried out. The specific test results are shown in Table 2, wherein the conventional mixing method is recorded as sample 1, the mixing method in (1) is recorded as sample 2, and the mixing method in (2) is recorded as sample 3.

[0093] 2. Floating test:

[0094] Example 2 was added into the water body according to the steps one and two in the above algae-removal test, the floating condition of the algae-removal agent on the water surface was observed, and the condition of the algae-removal agent in the water was observed after standing for 10 d.

[0095] Among them, the floating conditions of Example 2 in the water are consistent, and can stably float on the water surface and will not sink after 10 d. Specifically, taking Example 2-1 as an example, its floating condition is shown in the accompanying drawings of the specification. Figure 1

[0096] Table 1 Removal rates of algae cells and chlorophyll of floating type algae-removal agent

[0097] ​

[0098]

[0099] Table II Removal rate of algae and chlorophyll under different mixing modes

[0100]

[0101] According to Table I and Table II, Example 2-1 is the most preferred scheme in Example 2, and in combination with Example 2-1 to Example 2-4, it can be seen that there is no obvious difference in the removal rates of algae cells and chlorophyll before and after the recycling cycle between Example 2-2 to Example 2-4 and Example 2-1, indicating that the algae removal efficiency of the floating type algae removal agent obtained in Example 2-2 to Example 2-4 has no obvious difference with Example 2-1. The reason may be that the difference between Example 2-2 to Example 2-4 and Example 2-1 is only that the mass ratio of the floating type aerogel algae removal catalyst to the persulfate is different, and the mass ratio of the floating type aerogel algae removal catalyst to the persulfate in Example 2-2 to Example 2-4 changes within the required range, indicating that changing the mass ratio of the floating type aerogel algae removal catalyst to the persulfate within the required range has no obvious effect on the performance of the obtained floating type algae removal agent.

[0102] In combination with Example 2-1, Example 2-5 to Example 2-8, it can be seen that there is no obvious difference in the removal rates of algae cells and chlorophyll before and after the recycling cycle between Example 2-5 to Example 2-8 and Example 2-1, indicating that the algae removal efficiency of the floating type algae removal agent obtained in Example 2-5 to Example 2-8 has no obvious difference with Example 2-1. The reason may be that the difference between Example 2-5 to Example 2-8 and Example 2-1 is that the ratio of raw materials in the preparation process of the floating type aerogel algae removal catalyst changes within the required range, indicating that changing the ratio of raw material metal salt and poly cyanamide within the required range has no obvious effect on the performance of the obtained algae removal agent.

[0103] In combination with Example 2-1, Example 2-9 to Example 2-11, it can be seen that there is no obvious difference in the removal rates of algae cells and chlorophyll before and after the recycling cycle between Example 2-9 to Example 2-11 and Example 2-1, indicating that the algae removal efficiency of the floating type algae removal agent obtained in Example 2-9 to Example 2-11 has no obvious difference with Example 2-1. The reason may be that the difference between Example 2-9 to Example 2-11 and Example 2-1 is that the selection of raw materials in the preparation process of the floating type aerogel algae removal catalyst changes within the required range, indicating that the replacement of single metal iron, manganese and dicyandiamide has no obvious effect on the performance of the obtained algae removal agent.

[0104] In combination with Example 2-1, Example 2-12 and Example 2-13, it can be seen that the removal rates of algal cells and the removal rates of chlorophyll before and after the recycling of the algal cells in Example 2-12 and Example 2-13 are not obviously different from those in Example 2-1, indicating that the algal removal efficiency of the floating type algal removal agent obtained in Example 2-12 and Example 2-13 is not obviously different from that in Example 2-1. The reason can be that the amount of the algal removal agent added in the water body in Example 2-12 and Example 2-13 varies within the required range, indicating that the change of the amount of the algal removal agent within the required range has little effect on the algal removal efficiency.

[0105] In combination with Example 2-1, Example 2-14 and Example 2-15, it can be seen that the removal rates of algal cells and the removal rates of chlorophyll before and after the recycling of the algal cells in Example 2-14 and Example 2-15 are lower than those in Example 2-1, indicating that the algal removal efficiency of the floating type algal removal agent obtained in Example 2-14 and Example 2-15 is lower than that in Example 2-1. The reason can be that the amount of the metal salt added in the preparation process of the floating type aerogel algal removal catalyst used in Example 2-14 and Example 2-15 varies outside the required range. As shown in Example 2-14, when the amount of the metal salt is very small, the content of the single metal atom in the system decreases, the ability and efficiency of the catalytic decomposition of the persulfate salt decrease, and thus the algal removal efficiency of the obtained floating type algal removal agent decreases. When the amount of the metal salt increases, as shown in Example 2-15, the content of the single metal atom crosslinked with the guar gum in the system has reached saturation during the preparation of the catalyst, and further addition will enhance the agglomeration between the metal atoms, resulting in the decrease of the algal removal efficiency.

[0106] Compared with Example 2-1, Example 2-16 to Example 2-18, it can be seen that the removal rates of algal cells and chlorophyll before and after the recycling of Example 2-16 to Example 2-18 are lower than those of Example 2-1, and the removal rate of algal cells after the recycling of Example 2-18 decreases significantly, indicating that the algal removal efficiency of the floating type algal removal agent obtained in Example 2-16 to Example 2-18 is lower than that of Example 2-1. The reason may be that the addition amount of polycyanine in the preparation process of the floating type aerogel algal removal catalyst used in Example 2-16 to Example 2-18 is changed outside the required range. In Example 2-16, the addition amount of polycyanine is reduced. On the one hand, the electron-donating effect of the amino group in polycyanine and the adjustment effect between metal ions and guar gum are lacking, which makes the distribution of metal ions in the obtained algal removal agent uneven, and the algal removal efficiency decreases. On the other hand, the carbon nitride structure introduced by polycyanine is lacking, and the stability of the obtained aerogel algal removal catalyst decreases. After recycling, the loss of metal ions is large, and the algal removal rate decreases significantly. In Example 2-18, no polycyanine is added, and the algal removal rate decreases significantly after the recycling.

[0107] Compared with Example 2-1, Example 2-19 and Example 2-20, it can be seen that the removal rates of algal cells and chlorophyll before and after the recycling of Example 2-19 are lower than those of Example 2-1, and the removal rates of algal cells and chlorophyll before and after the recycling of Example 2-20 are slightly higher than those of Example 2-1, indicating that the algal removal efficiency of the floating type algal removal agent obtained in Example 2-19 is lower than that of Example 2-1. The reason may be that the difference between Example 2-19 and Example 2-20 and Example 2-1 is that the mass ratio of the floating type aerogel algal removal catalyst to the persulfate in the algal removal agent is changed outside the required range. In Example 2-19, the content of persulfate decreases, and the algal removal efficiency decreases. In Example 2-20, the content of persulfate increases, and the algal removal efficiency increases.

[0108] Compared with Example 2-1 and Comparative Example 2-1, it can be seen that the removal rates of algal cells and chlorophyll before and after the recycling of Comparative Example 2-1 are lower than those of Example 2-1, and the removal rate of algal cells after the recycling decreases significantly. The reason may be that the catalyst added in Comparative Example 2-1 is zero-valent copper, which has a certain catalytic decomposition effect on persulfate. On the one hand, there is no synergistic cooperation of guar gum in removing algae, and on the other hand, there is no guar gum as a carrier, which makes it difficult to be recycled and treated, and the loss rate of metal ions increases significantly, and the corresponding algal removal rate decreases significantly.

[0109] In combination with sample 1, sample 2 and sample 3, it can be seen that the removal rates of algal cells and chlorophyll before and after the recycling cycle of sample 2 are lower than those of sample 1 and sample 3. The reason may be that the mixing of the floating type algae-removing agent in sample 2 is only mixed at a medium speed, compared with the mixing method in sample 1 and sample 3, the contact probability between the catalyst and the persulfate in sample 2 is reduced, and a certain suspended structure cannot be formed in the water body, resulting in a decrease in the final algae-removal efficiency.

[0110] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A floating type algae removing agent, characterized by, The raw materials of the floating type algae-removing agent include a floating type aerogel algae-removing catalyst and a persulfate salt; the floating type aerogel algae-removing catalyst takes guar gum as a carrier matrix and is loaded with single metal atoms; the single metal atoms include one of copper atoms, iron atoms, cobalt atoms and manganese atoms. The preparation method of the floating type aerogel algae-removing catalyst includes the following steps: S1. adding a metal salt into deionized water and stirring to dissolve to obtain a metal ion aqueous solution; S2. adding melamine and guar gum into the metal ion aqueous solution obtained in the step S1, increasing the temperature to 30-35℃ and stirring to dissolve; after dissolution, standing at room temperature for 45-50h to obtain a metal ion crosslinked hydrogel; S3. freeze-drying the metal ion crosslinked hydrogel for 70-72h to obtain a metal ion crosslinked aerogel; S4. under a nitrogen atmosphere, performing carbonization treatment on the metal ion crosslinked aerogel, the carbonization temperature is 700-720℃ and the carbonization time is 2-3h; S5. performing several times of acid immersion and cleaning on the metal ion crosslinked aerogel after the carbonization treatment until the metal ion crosslinked aerogel is neutral; and then performing drying treatment to obtain the floating type aerogel algae-removing catalyst.

2. The floating type algae removing agent according to claim 1, characterized by, The floating type aerogel algae-removing catalyst includes the following raw materials by mass fraction: guar gum 1 part; metal salt 0.15-0.3 parts; melamine 1-3 parts.

3. The floating type algae removing agent according to claim 2, characterized by, The metal salt includes one of copper nitrate, manganese nitrate, cobalt nitrate, iron nitrate, copper sulfate, iron sulfate, manganese sulfate monohydrate, copper chloride and iron chloride.

4. The floating type algae removing agent according to claim 1, wherein The mass ratio of the floating type aerogel algae-removing catalyst to the persulfate salt is (0.6-0.8):(0.1-0.15).

5. The floating type algae removing agent according to claim 1, wherein The persulfate salt includes one or a combination of several of potassium monopersulfate, potassium persulfate and sodium monopersulfate.

6. The floating type algae removing agent according to claim 1, wherein The use process of the floating type algae-removing agent includes: adding the floating type algae-removing agent into water and mixing; the floating type algae-removing agent forms a floating state on the surface of the water and performs algae-removing work.

7. The floating type algae removing agent according to claim 6, wherein The addition amount of the floating type algae-removing agent is 0.2-1g / L.

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