Zinc gallium spinel, method for preparing same, and use thereof

Abstract

This invention belongs to the field of inorganic material synthesis and photocatalytic degradation of organic matter, and provides a zinc gallium spinel, its preparation method, and its applications. The preparation method of this invention uses zinc oxide and gallium salt as raw materials, and a low molar ratio (M...) can be obtained through a solid-liquid reaction. 2+ M 3+ The zinc-gallium layered double hydroxide (ZGLD) precursor of zinc-gallium spinel exhibits a three-dimensional structure composed of interlaced nanosheets. Due to the lattice positioning effect of ZGLD, the in-situ synthesis method using it as a precursor can achieve high dispersion and molecular-level contact of reactant metal ions, greatly improving the overall uniformity of the product. Calcining ZGLD directly yields high-purity ZGLD without metal oxide doping. Therefore, the method of this invention has the advantages of efficient and simple preparation process, high product purity, and uniform structure and composition. Examples show that the obtained ZGLD is plate-shaped, pure-phase ZGLD, and has good crystallinity.

Description

Technical Field

[0001] This invention relates to the field of inorganic material synthesis and photocatalytic degradation of organic matter, specifically to a zinc gallium spinel, its preparation method, and its applications. Background Technology

[0002] Antibiotics possess highly effective antibacterial properties and are widely used in the prevention and treatment of diseases in humans and animals. However, due to incomplete absorption and conversion of antibiotics in the body, they are frequently detected in the natural environment. For example, tetracycline has antibacterial activity against Gram-positive and Gram-negative bacteria, protozoa, mycoplasma, and spirochetes, and is widely used as an adjunct drug in cancer treatment, as well as in veterinary medicine and growth-promoting feed additives. However, over 70% of tetracycline is excreted and released into the environment through human and animal feces and urine, causing serious water and soil pollution.

[0003] To date, numerous treatment processes for removing antibiotics have been developed, such as adsorption, ozone oxidation, membrane filtration, and photocatalysis. Photocatalysis can ultimately convert organic pollutants into carbon dioxide and water, and can degrade structurally complex pollutants that are difficult to treat using traditional methods. It is considered a promising technology due to its high efficiency, low energy consumption, and environmental friendliness. Zinc gallium spinel is a type of silicate with... 10 It is a p-block ternary metal compound with high chemical and thermal stability, and has excellent photocatalytic performance.

[0004] Conventional methods for synthesizing zinc gallium spinel include solid-state reaction, sol-gel, hydrothermal synthesis, and metal-organic chemical vapor deposition. However, these methods typically involve high reaction temperatures (~1200℃), long reaction times (~24h), complex preparation processes, and expensive equipment. Furthermore, the resulting products are dense, difficult to sinter, and exhibit non-uniform composition.

[0005] Due to the lattice minimum energy effect and lattice positioning effect of layered bimetallic hydroxides (LDHs), the metal ions in the layers and the anions in the interlayers are uniformly distributed in a certain way, meaning that the chemical composition remains unchanged in each structural unit of LDHs. Therefore, it is expected that LDHs can be used as precursors to obtain spinels with uniform composition and structure at relatively low calcination temperatures and short calcination times.

[0006] However, in layered bimetallic hydroxide hydrotalcite synthesized by traditional methods such as salt-alkali coprecipitation, M... 2+ M 3+ The ratio is generally between 2 and 4, resulting in the calcined product being a mixed phase of divalent metal oxides and spinel. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a zinc gallium spinel, its preparation method, and its applications. The preparation method provided by the present invention can synthesize low proportions of M 2+ M 3+ The zinc-gallium spinel precursor hydrotalcite yields high-purity zinc-gallium spinel.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] This invention provides a method for preparing zinc gallium spinel, comprising the following steps:

[0010] Zinc oxide, gallium salt and water are mixed and then ground and crystallized sequentially to obtain zinc gallium spinel precursor;

[0011] The zinc gallium spinel precursor is calcined to obtain the zinc gallium spinel.

[0012] Preferably, the molar ratio of zinc oxide to gallium salt is 1:1.

[0013] Preferably, the gallium salt is gallium nitrate and / or gallium chloride.

[0014] Preferably, the mixing of zinc oxide, gallium salt, and water comprises: dispersing zinc oxide in water to obtain a zinc oxide dispersion; dissolving gallium salt in water to obtain a gallium salt solution; mixing the zinc oxide dispersion and the gallium salt solution; wherein the concentration of the gallium salt solution is 0.01–1 mol / L.

[0015] Preferably, the grinding speed is 2000-4000 rpm and the grinding time is 2-10 min.

[0016] Preferably, the crystallization temperature is 40–80°C and the time is 4–8 hours; the crystallization is carried out under stirring conditions.

[0017] Preferably, after crystallization, the reaction solution is centrifuged, and the resulting precipitate is washed and dried sequentially; the washing reagent is water and / or ethanol.

[0018] Preferably, the calcination temperature is 600-800℃, the heating rate to the calcination temperature is 5-10℃ / min, the calcination holding time is 2.5-5h, and the calcination atmosphere is air.

[0019] The present invention also provides zinc gallium spinel prepared by the preparation method described above, wherein the zinc gallium spinel is in the form of a plate.

[0020] The present invention also provides the application of zinc gallium spinel as described above in the photocatalytic degradation of organic matter.

[0021] This invention provides a method for preparing zinc gallium spinel, comprising the following steps: mixing zinc oxide, gallium salt, and water, and sequentially grinding and crystallizing to obtain a zinc gallium spinel precursor; calcining the zinc gallium spinel precursor to obtain the zinc gallium spinel. This invention uses zinc oxide and gallium salt as raw materials and can obtain a low molar ratio (M... 2+ M 3+ The zinc-gallium layered double hydroxide (ZGL) precursor of zinc-gallium spinel exhibits a three-dimensional structure composed of interlaced nanosheets. Due to the lattice positioning effect of LGL, the in-situ synthesis method using it as a precursor can achieve high dispersion and molecular-level contact of reactant metal ions, greatly improving the overall uniformity of the product. Calcining the ZGL directly yields high-purity ZGL without metal oxide doping. Therefore, the preparation method provided by this invention is highly efficient and simple, yielding a product with high purity and uniform structure and composition. The prepared plate-like ZGL exhibits excellent performance in photocatalytic degradation of organic matter and has good application prospects. Data from the examples show that the obtained ZGL is plate-like, pure-phase, and has good crystallinity.

[0022] Furthermore, the calcination temperature is 600–800°C, and the calcination holding time is 2.5–5 hours. Compared with other methods, the preparation method provided by this invention has a lower calcination temperature and duration than the traditional solid-phase reaction method (~1200°C, 12 hours), saving time and energy and reducing costs. Attached Figure Description

[0023] Figure 1 The image shows the XRD pattern of the zinc gallium spinel precursor obtained in Example 1.

[0024] Figure 2 This is a TEM image of the zinc gallium spinel precursor obtained in Example 1;

[0025] Figure 3 The XRD pattern of the zinc gallium spinel obtained in Example 1;

[0026] Figure 4 This is a TEM image of the zinc gallium spinel obtained in Example 1;

[0027] Figure 5 The UV absorption spectra of zinc gallium spinel before and after the photocatalytic degradation of tetracycline in Application Example 1 are shown.

[0028] Figure 6 The UV absorption spectra of zinc gallium spinel before and after the photocatalytic degradation of ciprofloxacin in Application Example 2 are shown.

[0029] Figure 7 The image shows the UV absorption spectra before and after the photocatalytic degradation of tetracycline by zinc gallium spinel in Application Example 3. Detailed Implementation

[0030] This invention provides a method for preparing zinc gallium spinel, comprising the following steps:

[0031] Zinc oxide, gallium salt and water are mixed and then ground and crystallized sequentially to obtain zinc gallium spinel precursor;

[0032] The zinc gallium spinel precursor is calcined to obtain the zinc gallium spinel.

[0033] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0034] This invention involves mixing zinc oxide, gallium salt, and water, followed by sequential grinding and crystallization to obtain a zinc-gallium spinel precursor.

[0035] In this invention, the gallium salt is preferably gallium nitrate and / or gallium chloride, more preferably gallium nitrate. In this invention, the molar ratio of zinc oxide to gallium salt is preferably 1:1. In this invention, the mixing of zinc oxide, gallium salt, and water preferably includes: dispersing zinc oxide in water to obtain a zinc oxide dispersion; dissolving the gallium salt in water to obtain a gallium salt solution; and mixing the zinc oxide dispersion and the gallium salt solution. In this invention, the concentration of the gallium salt solution is preferably 0.01–1 mol / L. In this invention, the dispersion of zinc oxide in water and the dissolution of the gallium salt in water are preferably carried out under stirring conditions.

[0036] In this invention, the grinding speed is preferably 2000-4000 rpm, more preferably 3000 rpm; the grinding time is preferably 2-10 min, more preferably 3 min. In this invention, the grinding is preferably performed in a colloid mill.

[0037] In this invention, the crystallization temperature is preferably 40-80°C, more preferably 50-70°C, and even more preferably 60°C; the time is preferably 4-8 hours; and the crystallization is preferably carried out under stirring conditions.

[0038] After crystallization, the present invention further includes centrifuging the resulting reaction solution, and washing and drying the resulting precipitate sequentially. In the present invention, the washing reagent is preferably water and / or ethanol, more preferably water, and the water is more preferably deionized water. In the present invention, the drying temperature is preferably 60°C, and the drying time is preferably 12 hours; the drying is preferably carried out in an oven.

[0039] After obtaining the zinc-gallium spinel precursor, the present invention calcines the zinc-gallium spinel precursor to obtain the zinc-gallium spinel.

[0040] In this invention, the calcination temperature is preferably 600-800℃, more preferably 650-750℃, and even more preferably 700℃; the heating rate to the calcination temperature is preferably 5-10℃ / min; the calcination holding time is preferably 2.5-5h; and the calcination atmosphere is preferably air.

[0041] Because the divalent and trivalent metal cations in the layered double hydroxide (LDH) are uniformly and orderly arranged in a certain manner, meaning that the chemical composition remains unchanged in each structural unit of LDHs, the zinc gallium spinel obtained by calcining LDH has a uniform composition and structure. During the calcination process, the loss of interlayer anions and water leads to lamellar breakage, but the spinel morphology still retains the original cross-linked lamellar structure of LDH, possessing uniform mesopores, which is beneficial for the photocatalytic degradation of organic matter.

[0042] The present invention also provides zinc gallium spinel prepared by the preparation method described in the above technical solution. In the present invention, the zinc gallium spinel is in the form of a plate.

[0043] The present invention also provides the application of zinc gallium spinel as described above in the photocatalytic degradation of organic matter.

[0044] In this invention, the organic compound preferably includes tetracycline and / or ciprofloxacin.

[0045] In this invention, when the zinc gallium spinel is used for photocatalytic degradation of organic matter, it preferably includes the following steps:

[0046] Zinc gallium spinel was added to a solution containing organic matter and then irradiated under a xenon lamp.

[0047] In this invention, the concentration of the zinc gallium spinel in the solution containing organic matter is preferably 0.4 g / L.

[0048] The zinc gallium spinel, its preparation method, and its applications provided by the present invention will be described in detail below with reference to the embodiments. However, these should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1

[0050] Weigh 1.63 g of zinc oxide and 5.11 g of gallium nitrate into 150 mL beakers, add 100 mL of deionized water to each, and pour evenly into a colloid mill. Grind at 3000 rpm for 3 min, then crystallize magnetically at 60 °C for 4 h. Centrifuge, wash the resulting precipitate with deionized water, and dry the precipitate in a 60 °C oven for 12 h to obtain the zinc gallium spinel precursor. The obtained zinc gallium spinel precursor contains M... 2+ M 3+ The molar ratio is 1:2.

[0051] Zinc gallium spinel precursor is placed in a muffle furnace and heated to 600°C at a rate of 5°C / min. It is then calcined at 600°C for 3 hours to obtain sheet-like zinc gallium spinel.

[0052] Figure 1 The XRD pattern of the obtained zinc gallium spinel precursor is shown below. Figure 1 It can be seen that the zinc gallium spinel precursor is zinc gallium hydrotalcite.

[0053] Figure 2 The TEM image of the obtained zinc gallium spinel precursor is shown below. Figure 2 It can be seen that zinc gallium hydrotalcite exhibits a three-dimensional structure composed of interlinked nanosheets.

[0054] Figure 3 The XRD pattern of the obtained zinc-gallium spinel is shown below. Figure 3 It can be seen that the product is pure-phase zinc gallium spinel with good crystallinity.

[0055] Figure 4 The TEM image of the obtained zinc gallium spinel is shown below. Figure 4 It can be seen that zinc gallium spinel has a plate-like structure.

[0056] Example 2

[0057] 3.26 g of zinc oxide and 10.22 g of gallium nitrate were weighed and placed in separate 150 mL beakers. 100 mL of deionized water was added to each beaker, and the mixture was poured evenly into a colloid mill and ground at 3000 rpm for 3 min. After crystallization with magnetic stirring at 50 °C for 6 h, the mixture was centrifuged. The resulting precipitate was washed with deionized water and dried in an oven at 60 °C for 12 h to obtain the zinc-gallium spinel precursor. The M in the obtained zinc-gallium spinel precursor... 2+ M 3+ The molar ratio is 1:2.

[0058] Zinc gallium spinel precursor is placed in a muffle furnace and heated to 700°C at a rate of 10°C / min. It is then calcined at 700°C for 3 hours to obtain sheet-like zinc gallium spinel.

[0059] Application Example 1

[0060] Degradation of tetracycline by zinc gallium spinel:

[0061] 0.02 g of the zinc-gallium spinel prepared in Example 1 was weighed into a 100 mL beaker, and 50 mL of tetracycline solution (100 mg / L) was added. After reaching adsorption equilibrium by magnetic stirring at room temperature for 30 min, a photodegradation experiment was conducted under simulated sunlight (xenon lamp, P = 300 W, λ = 350–780 nm) for 2 h. The absorption peak of tetracycline in the ultraviolet spectrum was located at 350–360 nm. After taking the supernatant solution, it was filtered through a 0.22 μm filter membrane, and the absorbance of tetracycline at 356 nm was measured by UV-Vis. The tetracycline concentration was then calculated using the Lambert-Beer law. The results showed that the prepared zinc-gallium spinel achieved a 90% removal rate of tetracycline within 2 h, with a removal amount of 225 mg / g, demonstrating an extremely high degradation rate. The ultraviolet absorption spectra of tetracycline before and after the reaction are shown below. Figure 5 As shown.

[0062] Application Example 2

[0063] Degradation of ciprofloxacin by zinc gallium spinel:

[0064] 0.02 g of the zinc-gallium spinel prepared in Example 1 was weighed into a 100 mL beaker, and 50 mL of ciprofloxacin solution (100 mg / L) was added. After reaching adsorption equilibrium by magnetic stirring at room temperature for 30 min, a photodegradation experiment was conducted under simulated sunlight (xenon lamp, P = 300 W, λ = 350–780 nm) for 2 h. The absorption peak of ciprofloxacin in the ultraviolet spectrum was located at ~270 nm. After taking the supernatant solution, it was filtered through a 0.22 μm filter membrane, and the absorbance of ciprofloxacin at 272 nm was measured by UV-Vis. The concentration of ciprofloxacin was then calculated using the Lambert-Beer law. The results showed that the prepared zinc-gallium spinel achieved a 60% removal rate of ciprofloxacin within 2 h, with a removal rate of 150 mg / g, exhibiting a high degradation rate. The ultraviolet absorption spectra of ciprofloxacin before and after the reaction are shown below. Figure 6 As shown.

[0065] Application Example 3

[0066] Degradation of tetracycline by zinc gallium spinel:

[0067] 0.02 g of the zinc-gallium spinel prepared in Example 2 was weighed into a 100 mL beaker, and 50 mL of tetracycline solution (100 mg / L) was added. After reaching adsorption equilibrium by magnetic stirring at room temperature for 30 min, a photodegradation experiment was conducted under simulated sunlight (xenon lamp, P = 300 W, λ = 350–780 nm) for 3 h. The absorption peak of tetracycline in the ultraviolet spectrum was located at 350–360 nm. After taking the supernatant solution, it was filtered through a 0.22 μm filter membrane, and the absorbance of tetracycline at 356 nm was measured by UV-Vis. The tetracycline concentration was then calculated using the Lambert-Beer law. The results showed that the prepared zinc-gallium spinel achieved a 95% removal rate of tetracycline within 3 h, with a removal amount of 240 mg / g, demonstrating an extremely high degradation rate. The ultraviolet absorption spectra of tetracycline before and after the reaction are shown below. Figure 7 As shown.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a zinc gallate spinel, characterized by, The method comprises the following steps: mixing zinc oxide, gallium salt and water, grinding and crystallizing in sequence to obtain a zinc gallium spinel precursor; firing the zinc gallium spinel precursor to obtain the zinc gallium spinel; the gallium salt is gallium nitrate and / or gallium chloride; the mixing of the zinc oxide, the gallium salt and the water comprises: dispersing the zinc oxide in water to obtain a zinc oxide dispersion; dissolving the gallium salt in water to obtain a gallium salt solution; mixing the zinc oxide dispersion and the gallium salt solution; the concentration of the gallium salt solution is 0.01-1 mol / L; the rotation speed of the grinding is 2000-4000 rpm, and the time is 2-10 min; the temperature of the crystallization is 40-80 ℃, and the time is 4-8 h; the crystallization is carried out under stirring; the firing temperature is 600-800 ℃, the heating rate for heating to the firing temperature is 5-10 ℃ / min, the holding time of the firing is 2.5-5 h, and the atmosphere of the firing is air.

2. The production method according to claim 1, characterized by, after the crystallization, the method further comprises centrifuging the obtained reaction liquid, and sequentially washing and drying the obtained precipitate; the washing reagent is water and / or ethanol.

3. The zinc gallium spinel produced by the production method according to any one of claims 1 to 2, characterized by the zinc gallium spinel is in a sheet shape.

4. Application of the zinc gallium spinel in claim 3 to photocatalytic degradation of organic matters.

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