Layered ternary nickel-iron-aluminum hydrotalcite as well as preparation method and application thereof

Abstract

The invention relates to the technical field of solid waste resource utilization, and discloses layered ternary nickel-iron-aluminum hydrotalcite as well as a preparation method and application thereof. The preparation method of the layered ternary nickel-iron-aluminum hydrotalcite comprises the following steps: (1) mixing red mud and inorganic acid, heating and leaching to obtain a leachate; and (2) mixing the leachate with urea and nickel salt, and carrying out hydrothermal reaction to obtain the layered ternary nickel-iron-aluminum hydrotalcite. The layered ternary nickel-iron-aluminum hydrotalcite crystal is prepared by taking the red mud as a raw material, so that the additional value of a red mud recycling product can be effectively increased, the comprehensive utilization rate of the red mud is improved, the preparation method is simple and high in universality, and the prepared layered ternary nickel-iron-aluminum hydrotalcite is uniform in morphology, large in specific surface area, wide in size regulation and control range and suitable for industrial production. And antibiotics in the wastewater can be effectively degraded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid waste resource utilization, in particular to a layered ternary nickel-iron-aluminum hydrotalcite and a preparation method and application thereof. BACKGROUND

[0002] Red mud is a strong alkaline waste residue produced in the extraction of alumina in the aluminum industry, which presents a red color due to the rich Fe2O3. In China, more than 90% of alumina and aluminum hydroxide products are produced by the Bayer process, and on average, 1-1.4 tons of red mud will be produced for every ton of alumina produced. However, the comprehensive utilization rate of red mud is less than 4% due to its strong alkalinity and complex composition. At present, in China and even in the world, the main treatment method for red mud is stockpiling. Red mud stockpiling not only occupies a large amount of land and increases maintenance costs, but also causes environmental problems such as soil alkalization and groundwater pollution as strong alkaline substances and heavy metal ions in red mud enter the soil and groundwater, and safety problems such as red mud dam collapse, which can cause significant harm to the local environment and society. How to properly dispose of and utilize red mud is a difficult problem that must be solved for the sustainable development of the alumina industry, which is of great significance to humans and the ecological environment. At present, the comprehensive utilization of red mud mainly focuses on building materials, roadbeds, valuable metal recovery, catalyst preparation, etc. The preparation process is not efficient, the cost is high, and the added value of the products is generally not high, resulting in a low utilization rate of red mud. Therefore, how to effectively increase the added value of red mud resource products and improve the comprehensive utilization rate of red mud is a problem that needs to be solved. SUMMARY

[0003] Therefore, the present application provides a layered ternary nickel-iron-aluminum hydrotalcite and a preparation method and application thereof, which can effectively increase the added value of red mud resource products and improve the comprehensive utilization rate of red mud by preparing the layered ternary nickel-iron-aluminum hydrotalcite from red mud.

[0004] In order to achieve the above-mentioned purposes, the present application adopts the following technical solutions: On the one hand, the present application provides a preparation method of a layered ternary nickel-iron-aluminum hydrotalcite, which comprises the following steps: (1) mixing red mud and inorganic acid, and heating leaching to obtain a leaching solution; (2) mixing the leaching solution, urea, and nickel salt, and performing hydrothermal reaction to obtain the layered ternary nickel-iron-aluminum hydrotalcite.

[0005] Preferably, the amount ratio of the inorganic acid to the red mud is 5-14 mL:1 g.

[0006] Preferably, the inorganic acid comprises at least one of hydrochloric acid and nitric acid.

[0007] Preferably, the mass concentration of the inorganic acid is 10-30%.

[0008] Preferably, the red mud comprises Fe2O3 5-30%, Al2O3 5-30%, SiO2 5-25%, TiO2 1-10%, Na2O 2-8% and CaO 5-15% in terms of mass percentage.

[0009] Preferably, the temperature of the heating leaching is 60-100℃ and the time is 1-6h.

[0010] Preferably, the mass ratio of the red mud to urea is 1:2-6.

[0011] Preferably, the total amount of substance ratio of nickel ions in the nickel salt to iron and aluminum ions in the red mud is 2-3.5:1.

[0012] Preferably, the nickel salt comprises at least one of nickel chloride, nickel nitrate and nickel sulfate.

[0013] Preferably, the reaction temperature of the hydrothermal reaction is 120-180℃ and the reaction time is 10-24h.

[0014] Preferably, after the hydrothermal reaction, the method further comprises the following steps: after the product obtained by the hydrothermal reaction is cooled to room temperature, centrifugation, washing and drying are performed to obtain the layered ternary nickel-iron-aluminum hydrotalcite.

[0015] In another aspect, the present application also provides a layered ternary nickel-iron-aluminum hydrotalcite prepared by any one of the above-mentioned methods.

[0016] Preferably, the size of the hydrotalcite is 0.5-1μm and the specific surface area is 60-150m 2 / g.

[0017] In addition, the present application also provides a layered ternary nickel-iron-aluminum hydrotalcite prepared by any one of the above-mentioned methods or the application of the above-mentioned layered ternary nickel-iron-aluminum hydrotalcite in antibiotic-containing wastewater.

[0018] The present application provides a layered ternary nickel-iron-aluminum hydrotalcite and a preparation method and application thereof, and has the beneficial effects compared with the prior art in that: The present application first uses an acid leaching method to dissociate iron and aluminum elements in the red mud in a liquid phase to obtain a leaching solution, then introduces urea and a nickel salt, and under hydrothermal conditions, the urea slowly decomposes to provide weak alkaline conditions and reacts with nickel ions to form an intermediate product, thereby promoting the formation of a layered ternary nickel-iron-aluminum hydrotalcite from iron and aluminum ions in the red mud and nickel ions.

[0019] The layered ternary nickel-iron-aluminum hydrotalcite crystal prepared from the red mud as a raw material can not only effectively increase the added value of the red mud resource product and improve the comprehensive utilization rate of the red mud, but also has the advantages of simple preparation method, strong universality, uniform morphology, large specific surface area, wide size control range, and can effectively degrade antibiotics in wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without any creative effort.

[0021] Figure 1 X-ray diffraction pattern of the product obtained in Example 1 of the present application; Figure 2 N2 adsorption isotherm curve of the product obtained in Example 1 of the present application; Figure 3 X-ray diffraction pattern of the product obtained in Example 2 of the present application; Figure 4 SEM image of the product obtained in Example 3 of the present application; Figure 5 X-ray diffraction pattern of the product obtained in Example 4 of the present application; Figure 6 X-ray diffraction pattern of the product obtained in Example 5 of the present application; Figure 7 X-ray diffraction pattern of the product obtained in Example 6 of the present application; Figure 8 X-ray diffraction pattern of the product obtained in Example 7 of the present application; Figure 9 X-ray diffraction pattern of the product obtained in Comparative Example 1 of the present application; Figure 10 Comparison chart of tetracycline hydrochloride degradation performance of the products of Example 1, 2 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0022] The present application will be described in detail through specific examples, and those skilled in the art can understand that the following specific examples are only for illustrative purposes, and do not limit the scope of the present application in any way. In addition, in the following examples, unless otherwise specified, the reagents and equipment used are commercially available. If the specific processing conditions and methods are not explicitly described in the following examples, the known conditions and methods in the art can be used for processing.

[0023] In one aspect of the present application, the present application provides a preparation method of layered ternary nickel-iron-aluminum hydrotalcite, comprising the following steps: (1) mixing red mud and inorganic acid, and heating leaching to obtain a leaching solution; (2) mixing the leaching solution, urea and nickel salt, and performing hydrothermal reaction to obtain layered ternary nickel-iron-aluminum hydrotalcite.

[0024] In the present application, first, red mud and inorganic acid are mixed, and heating leaching is performed to obtain a leaching solution.

[0025] In some embodiments of the present application, the use amount ratio of the inorganic acid and the red mud is 5-14 mL:1 g, and specifically can be 5 mL:1 g, 8 mL:1 g, 10 mL:1 g, 12 mL:1 g and 14 mL:1 g, etc. The inorganic acid includes at least one of hydrochloric acid and nitric acid. The mass concentration of the inorganic acid is 10-30%, and specifically can be 10%, 20% and 30%, etc. The acid leaching method adopted in the present application can dissociate iron and aluminum elements in the red mud, and by limiting the use amount ratio (i.e. liquid-solid ratio) of the inorganic acid and the red mud and the concentration of the inorganic acid, the iron and aluminum elements in the red mud can be fully dissociated.

[0026] In some embodiments of the present application, the red mud is an alkaline solid waste generated in the process of preparing aluminum oxide or aluminum hydroxide product by Bayer process, sintering method or combined method. In terms of mass percentage, the red mud includes Fe2O3 5-30%, Al2O3 5-30%, SiO2 5-25%, TiO2 1-10%, Na2O 2-8% and CaO 5-15%. The present application uses red mud as raw material to prepare layered ternary nickel-iron-aluminum hydrotalcite, which not only can effectively increase the added value of the red mud resource product, but also can effectively improve the comprehensive utilization rate of the red mud.

[0027] In some embodiments of the present application, the temperature of the heating leaching is 60-100℃, and specifically can be 60℃, 80℃ and 100℃, etc., and the time is 1-6 h, and specifically can be 1 h, 2 h, 4 h and 6 h, etc. Specifically, the heating leaching can be constant temperature stirring at 60-100℃ for 1-6 h, and by heating leaching, the iron and aluminum elements in the red mud can be more fully dissociated.

[0028] In some embodiments of the present application, after the heating leaching, the following step is further included: performing solid-liquid separation on the leaching product obtained after the heating leaching to obtain a leaching solution. It should be noted that the solid-liquid separation is a conventional operation, for example, a vacuum pump can be used for solid-liquid separation, and the present application does not specially limit the solid-liquid separation, which can be adjusted according to the actual situation.

[0029] In the present application, after obtaining the leaching solution, the leaching solution is mixed with urea and a nickel salt to perform a hydrothermal reaction to obtain layered ternary nickel-iron-aluminum hydrotalcite.

[0030] In some embodiments of the present application, the mass ratio of the red mud to urea is 1:2-6, and can be 1:2, 1:4, 1:6, etc. The present application uses non-toxic and inexpensive urea. Under hydrothermal conditions, urea is decomposed to generate OCN - , forming a weak alkaline environment, and OCN - reacts with nickel ions to form an intermediate product NiNCO + , which can promote the formation of Al-Fe-NiO crystal nucleus, thereby effectively improving the growth of ternary nickel-iron-aluminum hydrotalcite crystals and inhibiting the formation of nickel hydroxide crystal phase. Moreover, if the amount of urea added is too much, the intermediate product will be formed too fast, thereby reducing the concentration of hydrotalcite crystal nucleus and producing impurities such as Ni(OH)2.

[0031] In some embodiments of the present application, the total amount-of-substance ratio of nickel ions in the nickel salt to iron and aluminum ions in the red mud is 2-3.5:1, and can be 2:1, 2.5:1, 3:1, 3.5:1, etc. The nickel salt includes at least one of nickel chloride, nickel nitrate, and nickel sulfate. Under the weak alkaline conditions provided by urea, the iron and aluminum ions in the red mud react with the nickel ions to form layered ternary nickel-iron-aluminum hydrotalcite crystals. If the amount of nickel element added is insufficient, excessive iron element will be generated in the hydrothermal process to form FeOOH crystal phase, affecting the generation of layered ternary nickel-iron-aluminum hydrotalcite.

[0032] In some embodiments of the present application, the hydrothermal reaction is performed in a hydrothermal reaction kettle, the reaction temperature of the hydrothermal reaction is 120-180℃, and can be 120℃, 140℃, 160℃, 180℃, etc., and the reaction time is 10-24h, and can be 10h, 15h, 18h, 24h, etc. In the present application, urea is decomposed under hydrothermal conditions to form a weak alkaline environment, and reacts with nickel ions to form an intermediate product, which can promote the formation of ternary nickel-iron-aluminum hydrotalcite from the iron and aluminum ions and nickel ions in the red mud, thereby achieving the full utilization of the red mud. If the reaction temperature of the hydrothermal reaction is too low, it will affect the crystallinity of the hydrotalcite, thereby affecting the growth of the layered structure; and if the reaction temperature is too high, metal oxide impurities are likely to be generated.

[0033] In some embodiments of the present application, after the hydrothermal reaction, the following step is further included: after the product obtained by the hydrothermal reaction is cooled to room temperature, centrifugation, washing, and drying are performed to obtain layered ternary nickel-iron-aluminum hydrotalcite. The centrifugation, washing, and drying are all conventional operations, and the washing can use, for example, ethanol and deionized water, which are not specially limited in the present application and can be adjusted according to the actual situation.

[0034] In another aspect, the present invention also provides a layered ternary nickel-iron-aluminum hydrotalcite prepared by any of the methods described above, wherein the hydrotalcite has a size of 0.5-1 μm and a specific surface area of ​​60-150 m². 2 / g. The hydrotalcite prepared by this invention has a uniform morphology, large specific surface area, and a wide range of size control.

[0035] In another aspect, the present invention also provides the application of layered ternary nickel-iron-aluminum hydrotalcite in antibiotic-containing wastewater, wherein the antibiotic may be, for example, tetracycline hydrochloride. This layered ternary nickel-iron-aluminum hydrotalcite can achieve a degradation rate of up to 96% for antibiotics in wastewater.

[0036] The technical solutions of this invention will be clearly and completely described below with reference to specific embodiments. The embodiments in this application are only examples, and all other embodiments obtained by those skilled in the art of layered ternary nickel-iron-aluminum hydrotalcite without creative effort are within the scope of protection of this invention.

[0037] Example 1 This embodiment provides a method for preparing layered ternary nickel-iron-aluminum hydrotalcite, the specific steps of which are as follows: (1) Mix 100g of red mud with hydrochloric acid with a mass concentration of 25% (at a liquid-solid ratio of 7 mL / g), place it at 80℃ and stir for 3h for heating and leaching, and use a vacuum pump to separate the solid and liquid to obtain the leachate.

[0038] (2) The leachate, urea, and Ni(NO3)2·6H2O were mixed and stirred for 30 min to obtain a mixture. The mixture was transferred to a hydrothermal reactor and hydrothermally reacted at 150℃ for 12 h. The product obtained from the hydrothermal reaction was cooled to room temperature and centrifuged. It was washed with ethanol and deionized water and dried for 12 h to constant weight to obtain layered ternary nickel-iron-aluminum hydrotalcite. The mass ratio of red mud to urea was 1:3.5, and the molar ratio of nickel ions to the total amount of iron and aluminum ions in the red mud was 2.5:1.

[0039] like Figure 1 The image shows the X-ray diffraction pattern of the product obtained in this embodiment. As can be seen from the image, the characteristic peaks of the product obtained in this embodiment are consistent with the NiFe-LDHs spectrum (JCPDS#51-0463), indicating that the obtained product is layered ternary nickel-iron-aluminum hydrotalcite. Figure 2 The figure shows the N2 adsorption isotherm curve of the product obtained in this embodiment. The specific surface area of ​​the layered ternary nickel-iron-aluminum hydrotalcite product is calculated to be 146 m². 2 / g.

[0040] Example 2 This embodiment is basically the same as Embodiment 1, except that the mass ratio of red mud to urea is 1:2.

[0041] As shown in Figure 2, the SEM image of the product obtained in this example is shown. It can be seen from the figure that the morphology of the layered ternary nickel-iron-aluminum hydrotalcite product of this example is flaky, and the size is 0.5-1 μm. Figure 3 As shown in Figure 3, the X-ray diffraction pattern of the product obtained in this example is shown. It can be seen from the figure that the characteristic peaks of the product obtained in this example are consistent with the NiFe-LDHs pattern (JCPDS #51-0463), indicating that the product obtained is a layered ternary nickel-iron-aluminum hydrotalcite. Compared with Example 1, the intensity of the characteristic peaks attributed to the layered ternary nickel-iron-aluminum hydrotalcite in this example is significantly reduced, indicating that the addition of urea is conducive to the growth of the layered hydrotalcite structure, thereby forming more complete crystal particles.

[0042] Example 3 This example is basically the same as Example 1, and the only difference is that the mass ratio of red mud to urea is 1:6.

[0043] As shown in Figure 4, the SEM image of the product obtained in this example is shown. It can be seen from the figure that the morphology of the layered ternary nickel-iron-aluminum hydrotalcite product of this example is flaky, and the size is 0.5-1 μm. Figure 4 Example 4

[0044] This example is basically the same as Example 1, and the only difference is that the total amount-of-substance ratio of nickel ions to iron-aluminum ions in red mud is 2:1. As shown in Figure 5, the X-ray diffraction pattern of the product obtained in this example is shown. It can be seen from the figure that the characteristic peaks of the product obtained in this example are consistent with the NiFe-LDHs pattern (JCPDS #51-0463), indicating that the product obtained is a layered ternary nickel-iron-aluminum hydrotalcite. Compared with Example 1, the intensity of the characteristic peaks attributed to the layered ternary nickel-iron-aluminum hydrotalcite in this example is reduced, indicating that the reduction of the initial proportion of nickel ions will inhibit the formation process of the crystal nucleus of the ternary nickel-iron-aluminum hydrotalcite, thereby causing the yield and crystallinity of the final ternary nickel-iron-aluminum hydrotalcite to decrease.

[0045] Figure 5 Example 5 This example is basically the same as Example 1, and the only difference is that the total amount-of-substance ratio of nickel ions to iron-aluminum ions in red mud is 3.5:1.

[0046] As shown in Figure 6, the X-ray diffraction pattern of the product obtained in this example is shown. It can be observed from the figure that there are significant characteristic peaks attributed to the layered ternary nickel-iron-aluminum hydrotalcite (pattern (JCPDS #51-0463)), but at the same time there are characteristic peaks attributed to Ni(OH)2(pattern (JCPDS #51-0463)), indicating that the amount of nickel ions added needs to be accurately controlled, thereby ensuring the purity of the hydrotalcite product.

[0047] Example 6 Figure 6 This example is basically the same as Example 1, and the only difference is that the total amount-of-substance ratio of nickel ions to iron-aluminum ions in red mud is 3.5:1.

[0048] ​​This embodiment is basically the same as Embodiment 1, except that the hydrothermal reaction is carried out at 120°C for 24 hours.

[0049] like Figure 7 The figure shows the X-ray diffraction pattern of the product obtained in this embodiment. As can be seen from the figure, the characteristic peaks of the product obtained in this embodiment are consistent with the NiFe-LDHs spectrum (JCPDS#51-0463), indicating that the obtained product is layered ternary nickel-iron-aluminum hydrotalcite. However, compared with Example 1, the intensity of the characteristic peaks of the product in this embodiment is significantly weakened, indicating that the lower synthesis temperature is not conducive to the growth of layered hydrotalcite crystals, resulting in lower crystallinity of the particles.

[0050] Example 7 This embodiment is basically the same as Embodiment 1, except that the hydrothermal reaction is carried out at 180°C for 10 hours.

[0051] like Figure 8 The figure shows the X-ray diffraction pattern of the product obtained in this embodiment. As can be seen from the figure, the characteristic peaks of the product obtained in this embodiment are consistent with the NiFe-LDHs spectrum (JCPDS#51-0463), indicating that the obtained product is layered ternary nickel-iron-aluminum hydrotalcite. Compared with Example 1, the intensity of the characteristic peaks attributed to layered ternary nickel-iron-aluminum hydrotalcite in this embodiment is significantly enhanced, indicating that a suitable synthesis temperature is beneficial to the growth of the layered hydrotalcite structure, thereby forming more complete crystal particles.

[0052] Comparative Example 1 This comparative example is basically the same as Example 1, except that the molar ratio of nickel ions to the total amount of iron and aluminum ions in the red mud is 1.5:1.

[0053] like Figure 9 The figure shows the X-ray diffraction pattern of the product obtained in this comparative example. As can be seen from the figure, compared with Example 1, the characteristic XRD peaks of the layered ternary nickel-iron-aluminum layered double hydroxide were detected. However, characteristic diffraction peaks belonging to the FeOOH crystal phase (JCPDS#26-0792) also appeared at positions 27° and 35.2°. This is mainly due to insufficient nickel addition, leading to excessive iron forming the FeOOH crystal phase during the hydrothermal process. This result confirms that the amount of nickel salt added has a significant impact on the formation of the ternary nickel-iron-aluminum layered double hydroxide product.

[0054] Application examples The layered ternary nickel-iron-aluminum hydrotalcite obtained in Examples 1, 2, and Comparative Example 1 was applied to the degradation experiment of tetracycline hydrochloride-containing wastewater. The specific steps are as follows: 50 mg of layered ternary nickel-iron-aluminum hydrotalcite powder material (particle size of 650 nm) obtained from Example 1, Example 2 and Comparative Example 1, respectively, was dispersed in 100 mL of wastewater solution (containing 10 mg / L tetracycline hydrochloride), placed in a quartz reactor and magnetically stirred in the dark, and adsorbed for 30 min to reach adsorption equilibrium under light-proof conditions. Subsequently, simulated sunlight was irradiated (light source: xenon lamp, 300 W; wavelength: simulated sunlight; light intensity: 100 mW / cm 2 ), and samples were collected at different times to measure the concentration of tetracycline hydrochloride in the wastewater.

[0055] As shown in Figure 10 , it is a comparison chart of the degradation performance of layered ternary nickel-iron-aluminum hydrotalcite of Example 1, Example 2 and Comparative Example 1 on tetracycline hydrochloride. As can be seen from the chart, the layered ternary nickel-iron-aluminum hydrotalcite prepared from red mud using a simple process exhibits high treatment efficiency on wastewater containing tetracycline hydrochloride. The degradation rate of the layered ternary nickel-iron-aluminum hydrotalcite of Example 1 on tetracycline hydrochloride can reach 96.4% at 180 min, which is 2.63 times higher than that of Comparative Example 1. The degradation rate of the layered ternary nickel-iron-aluminum hydrotalcite of Example 2 on tetracycline hydrochloride can reach 91.3% at 180 min, which is 2.49 times higher than that of Comparative Example 1. The results show that the layered ternary nickel-iron-aluminum hydrotalcite prepared by the present application can be used to treat wastewater containing antibiotics, and the treatment effect is good.

[0056] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A process for the preparation of a layered ternary nickel iron aluminum hydrotalcite, characterized in that, The method comprises the following steps: (1) mixing red mud and inorganic acid, and heating leaching to obtain a leaching solution; (2) mixing the leaching solution, urea and a nickel salt, and performing a hydrothermal reaction to obtain a layered ternary nickel-iron-aluminum hydrotalcite.

2. The method for preparing layered ternary nickel iron aluminum hydrotalcite according to claim 1, characterized in that, The mass ratio of the inorganic acid to the red mud is 5-14 mL:1 g; The inorganic acid comprises at least one of hydrochloric acid and nitric acid, and the mass concentration of the inorganic acid is 10-30%.

3. The method for preparing layered ternary nickel iron aluminum hydrotalcite of claim 1, characterized in that, The red mud comprises, in terms of mass percentage, 5-30% of Fe2O3, 5-30% of Al2O3, 5-25% of SiO2, 1-10% of TiO2, 2-8% of Na2O and 5-15% of CaO.

4. The method for preparing layered ternary nickel iron aluminum hydrotalcite of claim 1, characterized in that, The temperature of the heating leaching is 60-100 DEG C, and the time is 1-6 h.

5. The method of preparation of layered ternary nickel iron aluminum hydrotalcite of claim 1, characterized by, The mass ratio of the red mud to urea is 1:2-6.

6. The method of preparation of layered ternary nickel iron aluminum hydrotalcite of claim 1, characterized by, The total amount-of-substance ratio of nickel ions in the nickel salt to iron-aluminum ions in the red mud is 2-3.5:

1. The nickel salt comprises at least one of nickel chloride, nickel nitrate and nickel sulfate.

7. The method of preparation of layered ternary nickel iron aluminum hydrotalcite of claim 1, characterized by, The reaction temperature of the hydrothermal reaction is 120-180 DEG C, and the reaction time is 10-24 h.

8. The process for the preparation of layered ternary nickel iron aluminum hydrotalcite according to any one of claims 1-7, characterized by the fact that, After the hydrothermal reaction, the following step is further included: centrifuging, washing and drying the product obtained in the hydrothermal reaction after being cooled to room temperature to obtain the layered ternary nickel-iron-aluminum hydrotalcite.

9. A layered ternary nickel iron aluminum hydrotalcite prepared according to the method of any one of claims 1 to 8, characterized in that, The size of the hydrotalcite is 0.5-1 μm, the specific surface area is 60-150 m 2 / g.

10. A layered ternary nickel-iron-aluminum hydrotalcite prepared by the method in any one of claims 1-8 or the layered ternary nickel-iron-aluminum hydrotalcite in claim 9, and application of the layered ternary nickel-iron-aluminum hydrotalcite in antibiotic-containing wastewater.

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