Nickel hydroxide, its preparation method, advanced oxidation reagent and application in water treatment

Abstract

The application provides a kind of nickel hydroxide and its preparation method, advanced oxidation reagent and application in water treatment, belong to catalytic technology field.The preparation method includes the following steps: S1, NaOH solution and nickel salt solution are mixed to obtain first mixed solution, then the pH of the first mixed solution is adjusted to 11-12, and the second mixed solution is obtained by standing treatment under room temperature condition;S2, the second mixed solution is activated at 50-60 DEG C, and the precipitate is separated;S3, the precipitate is washed and dried to obtain beta type nickel hydroxide.The nickel hydroxide obtained by the preparation method has excellent activation sodium percarbonate and / or sodium persulfate effect, and can improve its removal efficiency of organic pollutants.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to nickel hydroxide and its preparation method, advanced oxidizing agents, and their application in water treatment. Background Technology

[0002] With the development of my country's social economy and the upgrading of agricultural and chemical industrial technologies, more and more recalcitrant organic pollutants are being discharged into water bodies and are difficult to remove. Even if the concentration in the environment is very low, they can cause strong toxicological effects and ecological hazards, posing a potential threat to human health and ecological security.

[0003] Advanced oxidation technologies (AOCs) offer unique advantages in treating recalcitrant organic pollutants and are a promising wastewater treatment technology. Commonly used oxidants, such as sodium percarbonate and sodium persulfate, generate highly reactive hydroxyl radicals (·OH) and sulfate radicals (SO4) under the catalysis of catalysts. - ·) etc., can react with most organic pollutants to degrade them.

[0004] Sodium percarbonate (SPC, molecular formula 2Na₂CO₃·3H₂O₂), known as "solid hydrogen peroxide," can slowly release free hydrogen peroxide molecules in aqueous solution, thus possessing essentially the same oxidizing power as hydrogen peroxide. Compared to hydrogen peroxide, sodium percarbonate exhibits extremely high storage stability. In recent years, sodium percarbonate has made significant progress in the remediation of organic pollution in groundwater and the pre-oxidation of slightly polluted water sources. Studies have shown that, under the action of iron salt catalysts, sodium percarbonate can effectively oxidize and degrade organic pollutants in water bodies and has a stronger adaptability to solution pH.

[0005] Sodium persulfate (Na2S2O8), also known as sodium persulfate, is a strong oxidizing agent. In recent years, sodium persulfate has made significant progress in the remediation of organic pollution in groundwater and the pre-oxidation of slightly polluted water sources. Studies have shown that sodium persulfate can effectively oxidize and degrade organic pollutants in water. For example, patent application CN115338245A discloses a highly efficient catalytic method for removing organic matter from soil using sodium persulfate, its preparation method, and its application. By synthesizing a composite material, the biochar in the composite material can adsorb organic matter due to its porous properties. After a large amount of organic matter has been adsorbed, sodium persulfate is added. The single-atom catalyst in the composite material catalyzes the sodium persulfate, achieving precise oxidation and greatly improving the removal efficiency of organic matter. The unit catalysts Fe, Ni, and Co are derived from the halides and nitrates of Fe, Ni, and Co.

[0006] It can be seen that both homogeneous activated sodium percarbonate and homogeneous activated sodium persulfate systems cause secondary pollution to the reaction system because the catalyst added to the reaction system is not easy to recover and process. Therefore, there is an urgent need to design a new type of catalyst to avoid secondary pollution of the reaction system. Summary of the Invention

[0007] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention provide a nickel hydroxide, a method for its preparation, an advanced oxidizing agent, and its application in water treatment.

[0008] The method for preparing nickel hydroxide according to an embodiment of the present invention includes the following steps:

[0009] S1. Mix sodium hydroxide solution and nickel salt solution to obtain a first mixture, then adjust the pH of the first mixture to 11-12 and allow it to stand at room temperature to obtain a second mixture;

[0010] S2. The second mixture is activated at 50-60°C, and the precipitate is separated.

[0011] S3. The precipitate is washed and dried to obtain β-type nickel hydroxide.

[0012] The advantages and technical effects of the preparation method of this invention are as follows:

[0013] (1) In the preparation method of the present invention, sodium hydroxide and nickel salt are used as raw materials in step S1 and β-type nickel hydroxide is prepared by alkaline co-precipitation under room temperature. In step S2, β-type nickel hydroxide with higher catalytic activity is obtained by activation treatment. In step S3, impurities are removed by washing and drying, and finally β-type nickel hydroxide catalyst is obtained. The process is simple and easy to operate. Moreover, the preparation cycle of β-type nickel hydroxide catalyst is relatively short, and it has potential application prospects in the treatment of slightly polluted water sources or sewage.

[0014] (2) The β-type nickel hydroxide prepared by the preparation method of the present invention is a transition metal hydroxyl compound with a stable structure. It greatly improves the generation of strong oxidizing free radicals in the heterogeneous activated sodium percarbonate and / or sodium persulfate system, thereby improving the removal effect of sodium percarbonate and / or sodium persulfate on trace concentrations and recalcitrant organic pollutants in water.

[0015] (3) In step S1, the pH must be adjusted to an alkaline condition of 11-12, and in step S2, the activation temperature must be 50-60℃ to obtain the target product. Otherwise, the obtained product may not have the effect of activating sodium percarbonate and / or sodium persulfate or the activation effect may not be obvious.

[0016] (4) The β-type nickel hydroxide prepared can be used as a catalyst to form an advanced oxidizing agent with oxidants sodium percarbonate and / or sodium persulfate. It belongs to a heterogeneous activation system. Since the solid catalyst added to the reaction system is easy to recover and treat, it avoids the problem of introducing secondary pollution into the reaction system. It also has the characteristics of simple operation and convenient maintenance. Therefore, it has broad application prospects in the remediation of organic polluted groundwater or in water treatment with water discharge requirements.

[0017] In some embodiments, in step S1, the specific method for mixing the sodium hydroxide solution and the nickel salt solution is to add the sodium hydroxide solution dropwise to the nickel salt solution under stirring.

[0018] In some embodiments, in step S1, the molar ratio of sodium hydroxide to nickel salt is (2-2.5):1.

[0019] In some embodiments, in step S1, the molar concentration of the sodium hydroxide solution is 0.5-1 mol / L, and the molar concentration of the nickel salt solution is 0.2-0.5 mol / L.

[0020] In some embodiments, in step S1, the settling time is at least 1 hour.

[0021] In some embodiments, the settling time in step S1 is 1-2 hours.

[0022] In some embodiments, the activation treatment in step S2 lasts for at least 36 hours.

[0023] In some embodiments, the activation treatment in step S2 lasts for at least 36-48 hours.

[0024] In some embodiments, in step S3, the drying process specifically involves drying at a temperature below 60°C for 20-30 hours.

[0025] In some embodiments, step S3 further includes grinding and sieving after the drying process.

[0026] In some embodiments, in step S3, the particle size of the β-type nickel hydroxide is less than 0.35 mm.

[0027] This invention also provides a nickel hydroxide obtained by the aforementioned preparation method.

[0028] The advantages and technical effects of nickel hydroxide in the embodiments of the present invention are as follows:

[0029] The nickel hydroxide in this embodiment of the invention is of the β type, which has excellent activation effect on sodium percarbonate and / or sodium persulfate, thereby improving their removal efficiency for organic pollutants and achieving the purpose of efficiently removing trace concentrations and recalcitrant organic pollutants from water.

[0030] Furthermore, embodiments of the present invention also provide an advanced oxidizing agent, comprising sodium percarbonate and / or sodium persulfate with nickel hydroxide of the present invention.

[0031] The advantages and technical effects of the advanced oxidizing reagents in this invention are as follows:

[0032] β-nickel hydroxide acts as a catalyst, while sodium percarbonate and / or sodium persulfate act as oxidants. Together, they form a high-grade oxidizing agent. β-nickel hydroxide can effectively activate the oxidant to generate highly oxidizing free radicals, which can effectively remove organic pollutants from water.

[0033] Furthermore, embodiments of the present invention also provide the application of advanced oxidizing agents in water treatment.

[0034] The advantages and technical effects brought about by the application of the embodiments of the present invention are as follows:

[0035] The advanced oxidizing agent of this invention is used in water treatment, such as groundwater treatment and surface water treatment, and can effectively degrade organic pollutants therein. Attached Figure Description

[0036] Figure 1 This is the XRD pattern of the β-type nickel hydroxide prepared in Example 1;

[0037] Figure 2 These are graphs showing the degradation effects of nitrobenzene by the β-type nickel hydroxide-activated sodium percarbonate system prepared in Example 1, the β-type nickel hydroxide system prepared in Example 1 alone, and the sodium percarbonate system alone.

[0038] Figure 3 The images show the degradation effects of aniline by the β-type nickel hydroxide activated sodium persulfate system prepared in Example 1, the β-type nickel hydroxide system prepared in Example 1 alone, and the sodium persulfate system alone. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] This invention provides a method for preparing nickel hydroxide, comprising the following steps:

[0041] S1. Mix sodium hydroxide solution and nickel salt solution to obtain a first mixture, then adjust the pH of the first mixture to 11-12 and let it stand at room temperature to obtain a second mixture;

[0042] S2. The second mixture is activated at 50-60°C, and the precipitate is separated.

[0043] S3. The precipitate is washed and dried to obtain β-type nickel hydroxide.

[0044] Working principle: In the preparation method of this invention, step S1 uses sodium hydroxide and nickel salt as raw materials to prepare β-type nickel hydroxide by alkaline co-precipitation at room temperature. Step S2 is activated to obtain β-type nickel hydroxide with higher catalytic activity. Step S3 is washed and dried to remove impurities, and finally β-type nickel hydroxide catalyst is obtained. The process is simple and easy to operate. Moreover, the preparation cycle of β-type nickel hydroxide catalyst is relatively short, and it has potential application prospects in the treatment of slightly polluted water sources or sewage.

[0045] Furthermore, the prepared β-type nickel hydroxide is a transition metal hydroxyl compound with a stable structure, which significantly enhances the generation of strong oxidizing free radicals in the heterogeneous activated oxidant system, thereby improving the removal efficiency of the oxidant for trace recalcitrant organic pollutants in water. It is important to note that in step S1, the pH must be adjusted to an alkaline condition of 11-12, and the activation temperature in step S2 must be 50-60℃ to obtain the target product; otherwise, the obtained product may not have the effect of activating the oxidant or the activation effect may be insignificant.

[0046] The preparation method of this invention does not have any particular limitation on the nickel salt in step S1, as long as it is a soluble nickel salt, such as at least one of nickel acetate, nickel chloride, nickel nitrate and nickel sulfate.

[0047] In some embodiments, in step S1, the sodium hydroxide solution and the nickel salt solution are mixed by adding the sodium hydroxide solution dropwise to the nickel salt solution under stirring. This is done to promote a more complete reaction and facilitate the complete precipitation of nickel ions in the nickel salt solution. By the end of the addition, the nickel ions have essentially precipitated completely.

[0048] In some embodiments, in step S1, the molar ratio of sodium hydroxide to nickel salt is (2-2.5):1, for example, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, etc. A slight excess of nickel hydroxide compared to nickel salt is beneficial for the complete precipitation of nickel ions in the nickel salt.

[0049] In some embodiments, in step S1, the molar concentration of the sodium hydroxide solution is 0.5-1 mol / L, such as 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, etc., and the molar concentration of the nickel salt solution is 0.2-0.5 mol / L, such as 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, etc. Sodium hydroxide and nickel salt solutions within the above molar concentration ranges react more readily and effectively reduce the formation of impurities.

[0050] In some embodiments, the settling time in step S1 is at least 1 hour. The settling time is to ensure complete reaction between sodium hydroxide and nickel salt. If the settling time is too short, the reaction will not be complete, and nickel salt may be wasted. Preferably, the settling time is 1-2 hours, such as 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, etc. If the settling time is too long, the precipitation effect will not be significantly improved, the reaction will prolong the production time, and it will not improve work efficiency.

[0051] In the preparation method of this embodiment, step S2 involves activating the second mixture at 50-60°C, such as 50°C, 52°C, 54°C, 56°C, 58°C, and 60°C. This is to transform the β-type nickel hydroxide particles into an active state, thereby improving their ability to activate oxidants. When the activation temperature is below 50°C, the crystallinity of the β-type nickel hydroxide is low, and the proportion of amorphous nickel hydroxide is large, making it difficult to effectively improve the activity of the β-type nickel hydroxide. Conversely, when the activation temperature is too high, the obtained nickel hydroxide is prone to transform into other crystal forms, resulting in very low catalytic activity for activating oxidants.

[0052] In some embodiments, the activation treatment time in step S2 is at least 36 hours. If the activation treatment time is too short, it is not conducive to improving the activity of the β-type nickel hydroxide catalytic oxidant. Preferably, the activation treatment time is 36-48 hours, such as 36 hours, 38 hours, 40 hours, 42 hours, 44 hours, 46 hours, 48 ​​hours, etc. If the activation treatment time is too long, the activation effect will not be significantly improved; instead, it will prolong the production time and is not conducive to improving work efficiency.

[0053] In some embodiments, the preparation method of the present invention is carried out under normal pressure. This method is simple to operate, has good continuity, and is conducive to industrial-scale application.

[0054] In some embodiments, step S3 specifically involves repeatedly washing the precipitate with deionized water until the pH of the wash solution remains essentially unchanged after three consecutive washes. Washing the precipitate (β-type nickel hydroxide) to neutral is to remove impurities and alkaline solutions from the precipitate, thereby further improving the activity of β-type nickel hydroxide.

[0055] In some embodiments, in step S3, the drying process specifically involves drying at a temperature below 60°C, such as natural air drying, or drying at temperatures of 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, etc., for 20-30 hours, such as 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, etc.

[0056] In some embodiments, step S3 further includes grinding and sieving after drying. Grinding reduces the particle size of the dried precipitate, while sieving aims to obtain nickel hydroxide acyl catalysts with the desired particle size, which is more conducive to catalytic activity. There are no particular limitations on the grinding method; any commonly used grinding method in related technologies can be used, such as ball milling or manual grinding. The grinding time and the specifications of the sieve used for sieving need to be appropriately selected based on the desired particle size of β-type nickel hydroxide.

[0057] In some embodiments, in step S3, the particle size of β-type nickel hydroxide is less than 0.35 mm, such as nanoscale, 0.01 mm, 0.02 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, etc. β-type nickel hydroxide within this particle size range is easier to mix uniformly with oxidants and can better enhance the activity of advanced oxidizing agents when applied to water treatment.

[0058] In addition, this embodiment of the invention also provides nickel hydroxide, obtained by the aforementioned preparation method.

[0059] The nickel hydroxide in this embodiment of the invention is of the β type, which has excellent activating oxidant properties, can improve its removal efficiency for organic pollutants, and achieve the purpose of efficiently removing trace concentrations and recalcitrant organic pollutants from water.

[0060] Furthermore, embodiments of the present invention also provide an advanced oxidizing agent, comprising sodium percarbonate and / or sodium persulfate with nickel hydroxide of the present invention.

[0061] β-nickel hydroxide serves as a catalyst, while sodium percarbonate and / or sodium persulfate act as oxidants. Together, they form an advanced oxidizing agent. β-nickel hydroxide activates the oxidant to generate highly oxidizing free radicals, effectively removing organic pollutants from water. This advanced oxidizing agent belongs to a heterogeneous activation system. Because the solid catalyst added to the reaction system is easy to recover and treat, it avoids the problem of introducing secondary pollution into the reaction system. Furthermore, it features simple operation and convenient maintenance, thus showing broad application prospects in the remediation of organically polluted groundwater or in water treatment with strict discharge requirements.

[0062] It should be noted that the organic pollutants mentioned here can be at least one of hydrocarbons, polycyclic aromatic hydrocarbons, halogenated aromatic compounds, dyes, pesticides, oils, cyanides, etc.

[0063] Furthermore, embodiments of the present invention also provide the application of advanced oxidizing agents in water treatment.

[0064] The advanced oxidizing agent of this invention is used in water treatment, such as groundwater treatment and surface water treatment, and can effectively degrade organic pollutants therein.

[0065] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. Unless otherwise specified, all reagents used below are commercially available products.

[0066] Example 1

[0067] A nickel hydroxide and its preparation method, the preparation method comprising the following steps:

[0068] (1) Prepare a 0.3 mol / L nickel nitrate [Ni(NO3)2] solution and a 0.6 mol / L NaOH solution;

[0069] (2) Take 200 mL of nickel nitrate solution and turn on the magnetic stirrer to stir. Then add 200 mL of NaOH solution dropwise to the nickel nitrate solution to obtain the first mixture. Adjust the pH of the first mixture to 11.5 with sodium hydroxide solution, stop the magnetic stirrer, and let it stand at room temperature and pressure for 2 hours to obtain the second mixture.

[0070] (3) The second mixture was placed in a constant temperature box and activated at 55°C under normal pressure for 48 hours, and the precipitate was obtained by filtration;

[0071] (4) Wash the precipitate repeatedly with deionized water until the pH value of the wash solution remains basically unchanged for three consecutive washes, indicating that the precipitate has been washed to neutral. After washing, dry the precipitate at normal pressure and 60°C for 20 hours, then grind and sieve it. Take the part with uniform particle size (<0.35mm) for later use, and the desired β-type nickel hydroxide is obtained.

[0072] Example 2

[0073] The preparation method of this embodiment is the same as that of Example 1, except that in step (2), the pH is adjusted to 11.

[0074] Example 3

[0075] The preparation method of this embodiment is the same as that of Example 1, except that in step (2), the pH is adjusted to 12.

[0076] Example 4

[0077] The preparation method of this embodiment is the same as that of Example 1, except that the activation temperature in step (3) is 55°C.

[0078] Example 5

[0079] The preparation method of this embodiment is the same as that of Example 1, except that the activation temperature in step (3) is 50°C.

[0080] Example 6

[0081] The preparation method of this embodiment is the same as that of Example 1, except that the activation temperature in step (3) is 60°C.

[0082] Example 7

[0083] The preparation method of this embodiment is the same as that of Example 1, except that the activation time in step (3) is 12h.

[0084] Comparative Example 1

[0085] The preparation method of this comparative example is the same as that of Example 1, except that in step (2), hydrogen peroxide solution is added to adjust the pH of the mixture to 7.

[0086] Comparative Example 2

[0087] The preparation method of this comparative example is the same as that of Example 1, except that the activation temperature in step (3) is 100°C.

[0088] Performance testing:

[0089] (1) XRD test: The nickel hydroxide prepared in Examples 1-7 was subjected to XRD test respectively.

[0090] (2) Activation performance of sodium percarbonate: Mixed solutions of nitrobenzene, sodium percarbonate (taking 2Na2CO3·3H2O2 as an example) and catalysts of Examples 1-7 and Comparative Examples 1-2 were prepared respectively. The mass concentration of nitrobenzene was 100 μg / L, the mass concentration of sodium percarbonate was 1570 mg / L, and the mass concentration of catalyst was 400 mg / L. The reaction was carried out under normal temperature and pressure with stirring. After 240 min of reaction, samples were taken to measure the concentration of nitrobenzene and calculate the removal rate. The results are shown in Table 1.

[0091] In addition, a mixed solution of nitrobenzene, sodium percarbonate (taking 2Na2CO3·3H2O2 as an example), and β-type nickel hydroxide from Example 1 was prepared, wherein the mass concentration of nitrobenzene was 100 μg / L, the mass concentration of sodium percarbonate was 1570 mg / L, and the mass concentration of β-type nickel hydroxide from Example 1 was 400 mg / L. This system is a β-type nickel hydroxide-activated sodium percarbonate system, denoted as β-type Ni(OH)2+SPC. A mixed solution of nitrobenzene and sodium percarbonate was also prepared, wherein the mass concentration of nitrobenzene was 100 μg / L, the mass concentration of sodium percarbonate was 1570 mg / L, and the mass concentration of β-type nickel hydroxide was 0 mg / L. This system is a sodium percarbonate-only system, denoted as SPC. A mixed solution of nitrobenzene and β-type nickel hydroxide from Example 1 was prepared, wherein the mass concentration of nitrobenzene was 100 μg / L and the mass concentration of β-type nickel hydroxide from Example 1 was 400 mg / L. This system was a separate β-type nickel hydroxide system, denoted as β-type Ni(OH)₂. The reaction was carried out under stirring at room temperature and pressure. Samples were taken at different time points during the reaction to measure the concentration of nitrobenzene and calculate the removal rate. The results are as follows: Figure 2 As shown.

[0092] (3) Activation performance of sodium persulfate: A mixed solution of aniline, sodium persulfate (taking Na2S2O8 as an example) and catalysts of Examples 1-7 and Comparative Examples 1-2 was prepared respectively. The mass concentration of aniline was 1000 μg / L, the mass concentration of sodium persulfate was 238 mg / L, and the mass concentration of catalyst was 400 mg / L. The reaction was carried out under normal temperature and pressure with stirring. After 30 min of reaction, samples were taken to measure the concentration of aniline and calculate the removal rate. The results are shown in Table 1.

[0093] In addition, a mixed solution of aniline, sodium persulfate (taking Na2S2O8 as an example), and the β-type nickel hydroxide from Example 1 was prepared, wherein the mass concentration of aniline was 1000 μg / L, the mass concentration of sodium persulfate was 238 mg / L, and the mass concentration of the β-type nickel hydroxide from Example 1 was 400 mg / L. This system was a β-type nickel hydroxide-activated sodium persulfate system, denoted as β-type Ni(OH)2+PDS. A mixed solution of aniline and sodium persulfate was prepared, wherein the mass concentration of aniline was 1000 μg / L, the mass concentration of sodium persulfate was 238 mg / L, and the mass concentration of the β-type nickel hydroxide was 0 mg / L. This system was a sodium persulfate-only system, denoted as PDS. A mixed solution of aniline and the β-type nickel hydroxide from Example 1 was prepared, wherein the mass concentration of aniline was 1000 μg / L, and the mass concentration of the β-type nickel hydroxide from Example 1 was 400 mg / L. This system was a β-type nickel hydroxide-only system, denoted as β-type Ni(OH)2. The reaction was carried out under ambient temperature and pressure with stirring. Samples were taken at different time points during the reaction to measure the concentration C of aniline and calculate the ratio of the concentration C of aniline to the initial concentration C0 of aniline. The results are as follows: Figure 3 As shown.

[0094] Table 1. Removal rates of organic pollutants by catalyst-activated sodium percarbonate or sodium persulfate in Examples 1-7 and Comparative Examples 1-2

[0095] Activated sodium percarbonate system, nitrobenzene removal rate (%) Aniline removal rate (%) in the activated sodium persulfate system Example 1 66％ 96％ Example 2 63％ 95％ Example 3 61％ 95％ Example 4 70％ 97％ Example 5 72％ 98％ Example 6 68％ 97％ Example 7 43％ 67％ Comparative Example 1 23％ 34％ Comparative Example 2 29％ 41％

[0096] The nickel hydroxide prepared in Examples 1-7 were all β-type Ni(OH)₂, and the XRD pattern of the nickel hydroxide prepared in Example 1 was as follows: Figure 1 As shown.

[0097] from Figure 2 It can be seen that the nitrobenzene removal rate of the standalone β-nickel hydroxide system (β-Ni(OH)₂) is only 4%, and that of the standalone sodium percarbonate system (SPC) is only 21%. In contrast, the nitrobenzene removal rate of the β-nickel hydroxide-activated sodium percarbonate system (β-Ni(OH)₂ + SPC) is as high as 66%, demonstrating a better effect in degrading trace organic pollutants in water. Furthermore, the β-nickel hydroxide-activated sodium percarbonate system can efficiently degrade dissolved organic matter in water, reducing the formation potential of disinfection byproducts to a certain extent and decreasing the generation of conventional disinfection byproducts.

[0098] from Figure 3 It can be seen that the aniline removal rate of the standalone β-nickel hydroxide system (β-Ni(OH)2) is only 3%, and that of the standalone sodium persulfate system (PDS) is only 19%. In contrast, the aniline removal rate of the β-nickel hydroxide-activated sodium persulfate system (β-Ni(OH)2 + PDS) is as high as 96%, demonstrating a better effect in degrading trace organic pollutants in water. Furthermore, the β-nickel hydroxide-activated sodium persulfate system can efficiently degrade dissolved organic matter in water, reducing the formation potential of disinfection byproducts to a certain extent and minimizing the generation of conventional disinfection byproducts.

[0099] As can be seen from Table 1, the β-type nickel hydroxide prepared in Examples 1-7 can effectively activate sodium percarbonate or sodium persulfate, and has a high removal rate of organic pollutants. However, the preparation methods of Comparative Examples 1-2 are not within the range of pH value or activation temperature defined in this invention, resulting in amorphous nickel hydroxide, which has a poor removal rate of organic pollutants from activated sodium percarbonate or sodium persulfate.

[0100] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0101] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-grade oxidizing agent, characterized in that, The mixture includes sodium percarbonate and / or sodium persulfate with nickel hydroxide, and the method for preparing said nickel hydroxide includes the following steps: S1. Mix sodium hydroxide solution and nickel salt solution to obtain a first mixture, then adjust the pH of the first mixture to 11-12, and allow it to stand at room temperature to obtain a second mixture; S2. The second mixture is activated at 50-60°C to separate the precipitate; wherein the activation time is at least 36 hours. S3. The precipitate is washed and dried to obtain β-type nickel hydroxide; wherein the drying process is specifically natural air drying or drying at 40-58℃ for 20-30 hours.

2. The advanced oxidizing agent according to claim 1, characterized in that, In step S1, the specific method for mixing the sodium hydroxide solution and the nickel salt solution is as follows: the sodium hydroxide solution is added dropwise to the nickel salt solution under stirring.

3. The advanced oxidizing agent according to claim 1, characterized in that, In step S1, the molar ratio of sodium hydroxide to nickel salt is (2-2.5):

1.

4. The advanced oxidizing agent according to claim 1, characterized in that, In step S1, the molar concentration of the sodium hydroxide solution is 0.5-1 mol / L, and the molar concentration of the nickel salt solution is 0.2-0.5 mol / L.

5. The advanced oxidizing agent according to claim 1, characterized in that, In step S1, the settling time is at least 1 hour.

6. The advanced oxidizing agent according to claim 1, characterized in that, In step S1, the settling time is 1-2 hours.

7. The advanced oxidizing agent according to claim 1, characterized in that, In step S2, the activation treatment time is 36-48 hours.

8. The advanced oxidizing agent according to claim 1, characterized in that, In step S3, the drying process further includes grinding and sieving.

9. The advanced oxidizing agent according to claim 1, characterized in that, In step S3, the particle size of the β-type nickel hydroxide is less than 0.35 mm.

10. The use of the advanced oxidizing agent according to any one of claims 1-9 in water treatment.

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