Iron-based coordination modified boric acid excrement ammonia volatilization inhibitor and preparation method and application thereof

Abstract

The invention discloses an iron-based coordination modified boric acid excrement ammonia volatilization inhibitor as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a boric acid solution; adding ethylenediamine tetraacetic acid into the boric acid solution, and continuously stirring until a boric acid-organic ligand compound solution is generated; preparing a ferric sulfate solution; dropwise adding a ferric sulfate solution into the boric acid-organic ligand compound solution while stirring, heating and continuously stirring after dropwise adding, and cooling to room temperature to obtain a reaction mixture; and filtering or performing rotary evaporation on the reaction mixture to obtain a solid product, and washing and drying to obtain the ammonia volatilization blocking and controlling agent. The prepared ammonia volatilization inhibitor not only has the effects of inhibiting ammonia volatilization and further improving the retention rate of nitrogen in excrement, but also has the advantages that after boric acid is modified by iron-based coordination, the anti-interference capability of the material is improved, the influence of competitive adsorption or chemical reaction of other substances can be better resisted, and the effective inhibition on ammonia gas is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of ammonia treatment, and in particular to a feces ammonia volatilization inhibitor of iron-based coordinated modified boric acid, a preparation method and an application thereof. Background Art

[0002] Ammonia is a colorless gas with a pungent odor, which is widely present in a variety of natural and man-made environments, such as livestock farms, organic fertilizer production, agricultural planting, ecological environment and rural environment. Especially in the process of animal husbandry, a large amount of animal manure is produced in pig farms or other farms. The accumulation of animal manure will lead to the production of a large amount of ammonia, which not only pollutes the environment, but also may cause a series of problems to the health of humans and animals.

[0003] There are many types of inhibitors currently used to inhibit the volatilization of ammonia (NH3), mainly including chemical inhibitors, biological adsorbents and physical coverings. Chemical inhibitors, such as sodium bisulfate, aluminum sulfate and iron salts, effectively reduce ammonia volatilization by lowering the pH value of feces. Such inhibitors have shown significant inhibitory effects in both laboratory and field tests. For example, the application of sodium bisulfate in broiler houses can reduce ammonia emissions by about 50% and improve the quality of foot pads. Similarly, aluminum sulfate and iron sulfate salts also show significant ammonia emission reduction effects during the storage of livestock and poultry manure, up to more than 90%. Adsorbents such as zeolite combine with ammonia through their porous structure and chemical reaction to reduce ammonia concentration. They also show good effects in livestock and poultry breeding and manure treatment, with an emission reduction rate of up to 60%.

[0004] Although existing ammonia volatilization inhibitor products have achieved certain results in reducing ammonia emissions, they still have many defects. Adsorbents such as activated carbon and zeolite show good adsorption capacity in the laboratory, but in actual applications, the adsorption capacity is limited, they are easily saturated, and need to be replaced frequently, resulting in high treatment costs. Biosorbents such as biochar have a low adsorption capacity for ammonia and a limited scope of application. Although the acidification method can significantly reduce ammonia and greenhouse gas emissions, the use of acidic compounds may cause corrosion to livestock equipment and affect its long-term use. Some chemical reagents such as aluminum salts are toxic under certain conditions and cannot be used.

[0005] Therefore, there is an urgent need for a safe, stable, environmentally friendly ammonia volatilization inhibitor. Summary of the invention

[0006] The purpose of the present invention is to provide an iron-based coordinated modified boric acid feces ammonia volatilization inhibitor and a preparation method and application thereof, so as to solve the problems of low safety and poor stability of the ammonia volatilization inhibitor products commonly used in the market.

[0007] To achieve the above object, the first aspect of the present invention provides a method for preparing a feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid, comprising the following steps: (1) Adding boric acid into an organic solvent and stirring until the boric acid is completely dissolved to obtain a transparent boric acid solution; (2) adding ethylenediaminetetraacetic acid to the boric acid solution and continuing to stir until a boric acid-organic ligand complex solution is generated; (3) adding ferric sulfate into water and stirring until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution; (4) adding the ferric sulfate solution dropwise to the boric acid-organic ligand complex solution while stirring, and after the addition is complete, heating and stirring are continued, and cooling to room temperature to obtain a reaction mixture; (5) The reaction mixture is filtered or rotary evaporated to obtain a solid product, which is then washed and dried to obtain an ammonia volatilization inhibitor.

[0008] Preferably, in step (1), the organic solvent is ethanol, and the mass volume ratio of boric acid to ethanol is 1-5 g:50-100 mL.

[0009] Preferably, in step (1), the stirring temperature is 20-25° C., the rotation speed is 300-500 rpm, and the time is 30-60 min.

[0010] Preferably, in step (2), the mass ratio of EDTA to boric acid in the boric acid solution is 1-3:1-5.

[0011] Preferably, in step (2), the stirring time is continued for 2 to 4 hours.

[0012] In step (2) of the present invention, during the mixing of the boric acid solution and ethylenediaminetetraacetic acid (EDTA), the hydroxyl (-OH) group in the boric acid and the functional groups such as the carboxyl (-COOH) and amino (-NH2) in the EDTA may interact to form a boric acid-organic ligand complex. Whether the complex is formed can be preliminarily determined by observing the color change of the solution, the change of pH value, or by infrared spectroscopy (IR) analysis.

[0013] Preferably, in step (3), the mass volume ratio of ferric sulfate to water is 1-3 g:10-20 mL.

[0014] Preferably, in step (4), the volume ratio of the ferric sulfate solution to the boric acid-organic ligand complex solution is 10-20 mL:50-100 mL.

[0015] Preferably, in step (4), the dropping speed of the ferric sulfate solution is 1-2 mL / min, the heating temperature is 40-50° C., and the stirring time is continued for 4-6 h.

[0016] In the process of step (4) of the present invention, the ferric sulfate solution is slowly added dropwise to the boric acid-organic ligand complex solution, and the iron ions (Fe 3+ ) can coordinate with the functional groups in the boronic acid-organic ligand complex. For example, iron ions may form coordination bonds with the carboxyl and amino groups of EDTA and the hydroxyl groups of boronic acid.

[0017] In the present invention, whether the complex is formed can be judged by observing the change of its physical properties and using a spectral analysis method, such as observing the color change of the solution, which becomes light green or light yellow; using ultraviolet-visible spectroscopy (UV-Vis) analysis means, by monitoring the absorption change of the reaction system in the ultraviolet-visible spectral region, when an absorption peak consistent with the state of iron ions contained in the iron-based coordinated modified boric acid appears, it indicates that the primary product may have been formed, and the iron ions and their complexes have characteristic absorption peaks in the ultraviolet-visible region, Fe 2+ The complex generally has a weak absorption peak in the visible light region, and Fe 3+ The absorption peak of the complex is usually more obvious.

[0018] The present invention can also determine whether the complex is formed by observing the change of its physical properties and using a spectral analysis method, such as observing the change of the solution color to light green or light yellow; using infrared spectroscopy (FT-IR) analysis means, the reaction system is regularly tested by infrared spectroscopy during the reaction process, and when the change of the characteristic peak of boric acid and the appearance of a new peak are observed, it can be determined that the primary product may have been formed. Boric acid has its own specific infrared absorption peak, such as the BO stretching vibration peak at 1300-1400 cm -1 When the iron ion is coordinated with boric acid, the vibration frequency of the BO bond changes, and the peak moves toward the low wave number direction. At the same time, new absorption peaks may appear, such as the iron-oxygen (Fe-O) stretching vibration peak at 400~600cm -1 within the range.

[0019] Preferably, in step (5), the solid product is washed 2 to 3 times with ethanol, each washing amount is 5 to 10 mL, and then placed in a vacuum drying oven and dried at 40 to 50° C. for 4 to 6 hours.

[0020] Step (5) of the present invention is mainly for the separation and purification of the product. After the reaction is completed, the reaction mixture is cooled to room temperature. If a precipitate is generated, the precipitate is collected by filtration and filtered under reduced pressure using a Buchner funnel and filter paper. If no obvious precipitate is generated, the ethanol is evaporated at a temperature of 40-50° C. using a rotary evaporator to precipitate the product.

[0021] The second aspect of the present invention provides a feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid, which is prepared by the above-mentioned preparation method.

[0022] The present invention can further analyze and characterize the structure and composition of the product by means of inductively coupled plasma atomic emission spectrometry (ICP-AES). The high temperature generated by inductively coupled plasma is mainly used to atomize and excite the iron element in the sample. When the excited iron atoms return to the ground state, they emit light of a specific wavelength. The content of the iron element is determined by detecting the intensity of these characteristic spectral lines.

[0023] The third aspect of the present invention provides the use of a feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid, and the use of the feces ammonia volatilization inhibitor in inhibiting ammonia volatilization.

[0024] Therefore, the feces ammonia volatilization control agent using the iron-based coordination modified boric acid of the above structure, as well as the preparation method and application of the present invention have the following beneficial effects: (1) The ammonia volatilization inhibitor of the present invention improves the nitrogen retention rate in feces by inhibiting the release of ammonia, thereby improving the quality of the breeding environment, promoting the resource utilization of waste, and solving the environmental protection and resource efficiency problems of the farm.

[0025] (2) Compared with traditional chemical inhibitors, the ammonia volatilization inhibitors of the present invention, iron sulfate and boric acid, are more environmentally friendly, will not cause secondary pollution to soil and water, and have long-term economic benefits. The present invention not only provides an environmentally friendly and efficient ammonia volatilization control technology for farms, but also provides a sustainable fertilizer management solution for agricultural production.

[0026] (3) The ammonia volatilization inhibitor of the present invention has advantages in chemical structure. The iron ions (Fe 3+ ) can react with ammonia in solution to form a stable complex. This complexation allows the ammonia molecules to be tightly bound to the iron ions, thereby reducing the free mobility of ammonia in the system and reducing the possibility of its volatilization. The boron atom in the boric acid molecule has an empty orbital and can accept the lone pair of electrons in the ammonia molecule, thereby reacting with ammonia to form ammonium borate. Ammonium borate is a relatively stable compound that is not easy to decompose and volatilize at room temperature. In this way, ammonia is fixed in the ammonium borate, achieving the purpose of reducing ammonia volatilization. In addition, boric acid itself is a weak acid. In a system coexisting with ferric sulfate, it can help maintain the acidic environment of the solution to a certain extent, thereby enhancing the effect of ferric sulfate in promoting the conversion of ammonia into ammonium ions and further reducing the volatilization of ammonia.

[0027] (4) The ammonia volatilization inhibitor of the present invention has a stronger adsorption capacity. After the iron group is combined with boric acid, the presence of iron ions can provide more adsorption sites for ammonia. Boric acid modified by iron group coordination can not only act as a catalyst to promote chemical reactions, but also can utilize the adsorption properties of boric acid and the coordination effect of iron group to adsorb and separate specific molecules, thus realizing the integration of multiple functions. Ammonia is a typical Lewis base, and boric acid is a typical Lewis acid. The lone pair of electrons on the ammonia molecule can enter the empty orbital in the complex structure formed by the iron group and boric acid to form a more stable coordination bond, thereby enhancing the adsorption of ammonia. This stable structure allows the ammonia molecules to be more firmly bound to the system, reducing the volatilization of ammonia.

[0028] (5) The ammonia volatilization inhibitor of the present invention has higher reactivity. Boric acid itself is weakly acidic in water. After the iron-based coordination modification, the acidity of boric acid may be affected, making it easier to react with ammonia gas with acid-base. Monohydrated ammonia formed after ammonia gas dissolves in water can ionize ammonium ions and hydroxide ions. The hydroxide ions combine with the hydrogen ions in the boric acid to form water, thereby promoting the continuous absorption of ammonia gas. The presence of the iron group will adjust the rate and degree of this acid-base reaction, making the reaction more efficient and further inhibiting the volatilization of ammonia gas.

[0029] (6) The ammonia volatilization inhibitor of the present invention has a more stable long-term inhibitory effect, and the coordination effect between the iron group and boric acid can enhance the structural stability of the material. In the process of inhibiting ammonia volatilization, the material needs to maintain a stable structure to continue to function. The introduction of the iron group can form a more solid three-dimensional structure or network structure, making the distribution of boric acid in the material more uniform and stable, and not easily affected by the external environment and undergoing structural changes, thereby ensuring the long-term inhibitory effect on ammonia. In practical applications, there may be other substances or factors that interfere with the process of inhibiting ammonia volatilization. After the iron group coordinates and modifies the boric acid, the material's anti-interference ability may be improved, and it can better resist the competitive adsorption or chemical reaction of other substances, ensuring effective inhibition of ammonia.

[0030] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the appearance of the barrier control agent prepared in Example 1; Figure 2 This is the appearance of the barrier control agent prepared in Example 2; Figure 3 is the XRD pattern of the barrier control agent prepared in Example 1; Figure 4 This is the SEM image of the barrier control agent prepared in Example 1. DETAILED DESCRIPTION

[0032] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and a specific operation process, but the present invention is not limited to this embodiment.

[0033] Example 1 The preparation method of the feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid comprises the following steps: (1) Weigh 4 g of boric acid and slowly add it to 80 mL of ethanol. Use a magnetic stirrer to stir at room temperature of 25°C with the speed set to 400 rpm for 45 minutes until the boric acid is completely dissolved to obtain a transparent boric acid solution.

[0034] (2) Slowly add 2 g of EDTA to the boric acid solution, continue stirring at room temperature, keep the speed constant, and extend the reaction time to 3 hours to obtain a boric acid-organic ligand complex solution. In this process, the hydroxyl (-OH) group of boric acid can interact with the functional groups of EDTA such as carboxyl (-COOH) and amino (-NH2) to form a boric acid-organic ligand complex.

[0035] (3) Weigh 2 g of ferric sulfate and dissolve it in 15 mL of deionized water. Use a magnetic stirrer to stir at a speed of 400 rpm until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution.

[0036] (4) Slowly add the ferric sulfate solution to the boric acid-organic ligand complex solution at a rate of 1.5 mL per minute while stirring. After the addition is complete, heat the reaction system in a 45°C water bath and continue stirring for 5 hours. Within this temperature range, the iron ions (Fe 3+ ) can undergo coordination reaction with the functional groups in the boric acid-organic ligand complex.

[0037] (5) After the reaction is completed, the reaction mixture is cooled to room temperature. A precipitate is generated. The precipitate is collected by filtration and filtered under reduced pressure using a Buchner funnel and filter paper to obtain a solid product.

[0038] The solid product was washed with cold ethanol for 3 times, with 8 mL of ethanol used each time, to remove unreacted impurities. Finally, the product was placed in a vacuum drying oven and dried at 45° C. for 5 hours to obtain an ammonia volatilization inhibitor.

[0039] Example 2 The method for preparing a feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid comprises the following steps: (1) Weigh 2 g of boric acid and slowly add it to 75 mL of ethanol. Use a magnetic stirrer to stir at room temperature of 25°C at a speed of 450 rpm for 40 minutes until the boric acid is completely dissolved to obtain a transparent boric acid solution.

[0040] (2) Slowly add 1 g of EDTA to the boric acid solution, continue stirring at room temperature, keep the speed constant, and extend the reaction time to 4 hours to obtain a boric acid-organic ligand complex solution. In this process, the hydroxyl (-OH) group of boric acid can interact with the functional groups of EDTA such as carboxyl (-COOH) and amino (-NH2) to form a boric acid-organic ligand complex.

[0041] (3) Weigh 1.5 g of ferric sulfate and dissolve it in 20 mL of deionized water. Use a magnetic stirrer to stir at a speed of 450 rpm until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution.

[0042] (4) Slowly add the ferric sulfate solution to the boric acid-organic ligand complex solution at a rate of 2 mL per minute while stirring. After the addition is complete, heat the reaction system in a 50°C water bath and continue stirring for 5 hours. Within this temperature range, the iron ions (Fe 3+ ) can undergo coordination reaction with the functional groups in the boric acid-organic ligand complex.

[0043] (5) After the reaction was completed, the reaction mixture was cooled to room temperature. If there was no obvious precipitation, the ethanol was evaporated at 40°C using a rotary evaporator to precipitate a solid product.

[0044] The solid product was washed with cold ethanol for 3 times, with 6 mL of ethanol used each time, to remove unreacted impurities. Finally, the product was placed in a vacuum drying oven and dried at 40° C. for 6 hours to obtain an ammonia volatilization inhibitor.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that the ferric sulfate solution is directly added dropwise to the boric acid solution. The specific preparation steps are as follows: (1) Weigh 4 g of boric acid and slowly add it to 80 mL of ethanol. Use a magnetic stirrer to stir at room temperature of 25°C with the speed set to 400 rpm for 45 minutes until the boric acid is completely dissolved to obtain a transparent boric acid solution.

[0046] (2) Weigh 2 g of ferric sulfate and dissolve it in 15 mL of deionized water. Use a magnetic stirrer to stir at a speed of 400 rpm until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution.

[0047] (3) Slowly add the ferric sulfate solution dropwise to the boric acid solution at a rate of 1.5 mL per minute while maintaining stirring. After the addition is complete, heat the reaction system in a water bath at 45° C. and continue stirring for 5 hours to obtain a reaction mixture.

[0048] (4) After the reaction is completed, the reaction mixture is cooled to room temperature. A precipitate is generated. The precipitate is collected by filtration and filtered under reduced pressure using a Buchner funnel and filter paper to obtain a solid product.

[0049] The solid product was washed with cold ethanol for 3 times, with 8 mL of ethanol used each time, to remove unreacted impurities. Finally, the product was placed in a vacuum drying oven and dried at 45° C. for 5 hours to obtain an ammonia volatilization inhibitor.

[0050] Comparative Example 2 The difference between this comparative example and Example 1 is that the ferric sulfate solution is added dropwise to the EDTA solution. The specific preparation steps are as follows: (1) Slowly add 2 g of EDTA to 80 mL of ethanol, stir at room temperature, set the speed to 400 rpm, and react for 3 hours to obtain an EDTA solution.

[0051] (2) Weigh 2 g of ferric sulfate and dissolve it in 15 mL of deionized water. Use a magnetic stirrer to stir at a speed of 400 rpm until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution.

[0052] (3) Slowly add the ferric sulfate solution to the EDTA solution at a rate of 1.5 mL per minute while stirring. After the addition is complete, heat the reaction system in a 45°C water bath and continue stirring for 5 hours. Within this temperature range, the iron ions (Fe 3+ ) can undergo coordination reaction with the functional groups in the boric acid-organic ligand complex.

[0053] (4) After the reaction is completed, the reaction mixture is cooled to room temperature. A precipitate is generated. The precipitate is collected by filtration and filtered under reduced pressure using a Buchner funnel and filter paper to obtain a solid product.

[0054] The solid product was washed with cold ethanol for 3 times, with 8 mL of ethanol used each time, to remove unreacted impurities. Finally, the product was placed in a vacuum drying oven and dried at 45° C. for 5 hours to obtain an ammonia volatilization inhibitor.

[0055] Comparative Example 3 The difference between this comparative example and Example 1 is that after mixing the boric acid solution and the EDTA solution, the ferric sulfate solution is immediately added dropwise. The specific preparation process is as follows: (1) Weigh 4 g of boric acid and slowly add it to 40 mL of ethanol. Use a magnetic stirrer to stir at room temperature of 25°C at a speed of 400 rpm for 45 minutes until the boric acid is completely dissolved to obtain a transparent boric acid solution.

[0056] (2) Weigh 2 g of EDTA and add it to 40 mL of ethanol. Use a magnetic stirrer to stir at room temperature of 25°C at 400 rpm for 3 minutes until the EDTA is completely dissolved to obtain an EDTA solution.

[0057] (3) Weigh 2 g of ferric sulfate and dissolve it in 15 mL of deionized water. Use a magnetic stirrer to stir at a speed of 400 rpm until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution.

[0058] (4) Mix the boric acid solution and the EDTA solution to form a mixed liquid, and immediately slowly add the ferric sulfate solution dropwise to the mixed liquid at a rate of 1.5 mL per minute while maintaining stirring. After the addition is complete, heat the reaction system in a water bath at 45°C and continue stirring for 5 hours.

[0059] After the reaction was completed, the reaction mixture was cooled to room temperature, and a precipitate was generated. The precipitate was collected by filtration and filtered under reduced pressure using a Buchner funnel and filter paper to obtain a solid product.

[0060] The solid product was washed with cold ethanol for 3 times, with 8 mL of ethanol used each time, to remove unreacted impurities. Finally, the product was placed in a vacuum drying oven and dried at 45° C. for 5 hours to obtain an ammonia volatilization inhibitor.

[0061] Test example (1) Characterization of ammonia volatilization inhibitor The appearance of the ammonia volatilization control agents prepared in Example 1 and Example 2 was observed. Figure 1 and Figure 2 It can be seen that the ammonia volatilization inhibitor is in the form of light yellow powder.

[0062] The structure and composition of the product can be further analyzed and characterized by X-ray diffraction (XRD). Figure 3 . Figure 3 Solid-solid mixing and liquid-liquid mixing are two methods for preparing ammonia volatilization inhibitors. Solid-solid mixing is the mixing of boric acid solid and ferric sulfate solid, and liquid-liquid mixing is the mixing of ferric sulfate solution and boric acid solution. By comparison, the effects of different mixing methods on the crystal structure of the final sample can be analyzed. Figure 3It can be seen that the XRD patterns under the two mixing modes have certain differences in the peak positions and intensities, which indicates that the mixing mode affects the growth and formation process of the ammonia volatilization inhibitor.

[0063] The microstructure of the ammonia volatilization control agent prepared in Example 1 was characterized by SEM. Figure 4 It can be seen that the ammonia volatilization inhibitor has a large specific surface area, a regular and uniform structure, many adsorption sites distributed on the surface, and a relatively obvious porous structure, indicating that it has a certain adsorption capacity.

[0064] (2) Performance test of ammonia volatilization inhibitor ① Effects of different inhibitor addition methods on ammonia treatment Test process: The demonstration was carried out in a pig house of the Grassland Research Institute of the Chinese Academy of Agricultural Sciences. The pig house area is 220 square meters, and the number of pigs is 100. According to the mass ratio of ammonia volatilization inhibitor (prepared in Example 1) to pig manure of 1:100, the ammonia volatilization inhibitor was sprayed, applied on the surface, and mixed, and the ammonia concentration was directly measured by using an environmental sensor for ammonia detection. The test results are shown in Table 1.

[0065] The inhibition rate of ammonia volatilization = (initial ammonia concentration - ammonia concentration after application of ammonia volatilization inhibitor) / initial ammonia concentration × 100%.

[0066] The specific steps of spraying are: take solid ammonia volatilization inhibitor, disperse the inhibitor in water at a ratio of 1g:10ml, and spray it on the surface of pig manure through a sprayer.

[0067] The specific steps of surface application are: take solid ammonia volatilization inhibitor and add it directly to the surface of pig manure, so that the inhibitor evenly covers the surface of pig manure.

[0068] The specific steps of mixing and applying are: take solid ammonia volatilization inhibitor, add it directly into pig manure, and mix it evenly using tools.

[0069] Table 1 The inhibitory effect of different addition methods of the inhibitor on ammonia volatilization Inhibition rate% Control group 0 Mixed application 30.28 Table 53.07 spray 60.44 It can be seen from Table 1 that the ammonia volatilization inhibitor of the present invention can achieve the best ammonia volatilization inhibition effect by adding water and spraying it on feces.

[0070] ②Effects of different types of inhibitors on ammonia treatment According to the above test process, the ammonia volatilization control agent prepared in Example 1 was replaced by boric acid, ferric sulfate, the ammonia volatilization control agent prepared in Example 2, and the ammonia volatilization control agents of Comparative Examples 1 to 3 in a spraying manner. The test results are shown in Table 2.

[0071] Table 2 The inhibitory effect of different types of inhibitors on ammonia volatilization Inhibition rate% Control group 0 Example 1 60.44 Example 2 62.31 Boric acid 16.84 Ferrous Sulfate 31.16 Comparative Example 1 46.52 Comparative Example 2 38.64 Comparative Example 3 44.17 It can be seen from Table 2 that the ammonia volatilization inhibitor prepared by the present invention has the best inhibitory effect.

[0072] ③Effect of different spraying ratios of control agents on ammonia treatment According to the above test process, the mass ratio of ammonia volatilization control agent (prepared in Example 1) to pig manure was replaced with 1:50 and 1:100 by spraying. The test results are shown in Table 3.

[0073] Table 3 The inhibitory effect of different addition amounts of inhibitor on ammonia volatilization Inhibition rate% Control group 0 1:10 100 1:50 65.08 1:100 60.44 As can be seen from Table 3, for the ammonia volatilization inhibition effect, when the ratio of the inhibitor to pig manure is 1:10, the ammonia volatilization inhibition effect is the best, and the inhibition rate is 100%; when the ratio is 1:50, the ammonia inhibition rate is about 65%; when the ratio is 1:100, the ammonia inhibition rate is about 60%. The effects are similar when the ratio is 1:50 and 1:100, but both are better than the control group. From the perspective of cost control, the treatment with a ratio of 1:100 can still reduce nitrogen loss by 60%, which is conducive to reducing nitrogen loss.

[0074] ④Stability test results According to the above test process, boric acid, ferric sulfate, the ammonia volatilization control agent prepared in Example 1, the ammonia volatilization control agent prepared in Example 2, and the ammonia volatilization control agents of Comparative Examples 1 to 3 were used in a spraying manner for three months, and then the ammonia concentration was tested again. The test results are shown in Table 4.

[0075] Table 4 Stability test results Inhibition rate% Control group 0 Example 1 59.32 Example 2 60.87 Boric acid 12.56 Ferrous Sulfate 24.33 Comparative Example 1 39.17 Comparative Example 2 31.36 Comparative Example 3 37.08 It can be seen from Table 4 that the inhibition rate of the ammonia volatilization inhibitor prepared in Example 1 and Example 2 has hardly changed, indicating that the inhibitor prepared therefrom has good stability, while the inhibitors of boric acid, ferric sulfate and comparative examples 1 to 3 have all declined to varying degrees, indicating that their stability is poor and not conducive to long-term use.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a feces ammonia volatilization inhibitor of iron-based coordinated modified boric acid, characterized in that: The following steps are involved: (1) Adding boric acid into an organic solvent and stirring until the boric acid is completely dissolved to obtain a transparent boric acid solution; (2) adding ethylenediaminetetraacetic acid to the boric acid solution and continuing to stir until a boric acid-organic ligand complex solution is generated; (3) adding ferric sulfate into water and stirring until the ferric sulfate is completely dissolved to obtain a ferric sulfate solution; (4) adding the ferric sulfate solution dropwise to the boric acid-organic ligand complex solution while stirring, and after the addition is complete, heating and stirring are continued, and cooling to room temperature to obtain a reaction mixture; (5) The reaction mixture is filtered or rotary evaporated to obtain a solid product, which is then washed and dried to obtain an ammonia volatilization inhibitor.

2. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid according to claim 1, characterized in that: In step (1), the organic solvent is ethanol, and the mass volume ratio of boric acid to ethanol is 1-5 g:50-100 mL.

3. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid according to claim 1, characterized in that: In step (2), the mass ratio of EDTA to boric acid in the boric acid solution is 1-3:1-5.

4. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid according to claim 1, characterized in that: In step (3), the mass volume ratio of ferric sulfate to water is 1-3 g:10-20 mL.

5. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination modified boric acid according to claim 1, characterized in that: In step (4), the volume ratio of the ferric sulfate solution to the boric acid-organic ligand complex solution is 10-20 mL: 50-100 mL.

6. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination-modified boric acid according to claim 1, characterized in that: In step (4), the dropping speed of the ferric sulfate solution is 1-2 mL / min, the heating temperature is 40-50° C., and the stirring time is continued for 4-6 h.

7. The method for preparing the feces ammonia volatilization inhibitor of iron-based coordination modified boric acid according to claim 1, characterized in that: In step (5), the solid product is washed with ethanol for 2 to 3 times, with the amount of each wash being 5 to 10 mL, and then placed in a vacuum drying oven and dried at 40 to 50° C. for 4 to 6 hours.

8. An iron-based coordinated boric acid-modified feces ammonia volatilization inhibitor, characterized in that: Prepared by the preparation method described in any one of claims 1 to 7.

9. The use of the feces ammonia volatilization inhibitor of the iron-based coordination-modified boric acid according to claim 8, characterized in that: Application of fecal ammonia volatilization inhibitor in inhibiting ammonia volatilization.

Images