Bimetallic layered silicate catalyst based on natural zeolite and its application

Abstract

The present invention provides a natural zeolite-based bimetallic layered silicate catalyst. The natural zeolite is calcined and reacted with a bimetallic salt and an alkaline substance at a certain temperature. Urea, hexamethylenetetramine, or sodium hydroxide is used as a pH adjuster to react with the zeolite to provide silicate ions and promote the formation of layered silicate. The preparation method of the natural zeolite-based bimetallic layered silicate catalyst provided by the present invention provides an advanced oxidation catalytic degradation effect on organic pollutants in wastewater.

Description

Technical Field

[0001] The present invention provides a bimetallic layered silicate catalyst based on natural zeolite, a preparation method and application thereof, belonging to the field of catalyst materials; in particular, relates to a bimetallic layered silicate catalyst based on natural zeolite, a preparation method and application thereof in the field of advanced oxidation technology. Background Art

[0002] In recent years, transition metal-based catalysts with single or multiple metals such as Co, Ni, or Fe as active centers have become one of the important development directions of advanced oxidation catalysts. In particular, the multivalent states of bimetallic catalysts and the electronic conduction between different metal ions can synergistically improve the catalytic activity of transition metal-based catalysts.

[0003] Layered silicates (such as nickel, cobalt, and iron silicates), also known as phyllosilicates, are layered silicate clay compounds composed of polyhedrons of metal elements and silicate tetrahedrons. Layered silicates possess high stability and a unique layered structure, sharing the characteristics of metal-based compounds. Their use as catalysts demonstrates excellent catalytic activity in the fields of chemistry, the environment, and energy conversion. Currently, layered silicates are mostly synthesized directly using silicon-containing chemical reagents (such as tetraethoxysilane and sodium silicate), resulting in high costs. Furthermore, the preparation of layered silicates with specialized nanotube-like morphologies is relatively difficult, making them unsuitable for large-scale production.

[0004] Natural zeolites are hydrous, framework-like aluminosilicate minerals with large specific surface area, exchangeable cations, and the ability to adsorb organic pollutants. Furthermore, natural zeolites are abundant, inexpensive, and widely available, making them ideal pollutant adsorption and catalyst carrier materials. Synthesizing bimetallic layered silicates on the zeolite surface using natural zeolites as both raw material and carrier can simultaneously leverage the coupled synergistic effects of zeolite, bimetallic, and layered silicates. This approach can also improve the synthesis of layered silicate composites, further enhance the application of natural zeolites in environmentally functional materials, and fully enhance the high-value utilization of natural zeolites. Summary of the Invention

[0005] The object of the present invention is to prepare a catalyst that simultaneously exerts the coupled synergistic effect of zeolite, bimetal and layered silicate.

[0006] The specific technical solutions adopted are as follows:

[0007] In a first aspect, the present invention provides a bimetallic layered silicate catalyst based on natural zeolite, wherein the bimetallic layered silicate catalyst based on natural zeolite is prepared by the following method:

[0008] (1) calcining natural zeolite powder with a particle size of 0.2 to 200 μm at 300 to 700° C. for 2 to 4 hours (preferably calcining at 600° C. for 2 hours) to obtain calcined zeolite;

[0009] (2) The calcined zeolite described in step (1) is uniformly dispersed in deionized water, a soluble cobalt salt and a soluble metal salt are added, and the mixture is uniformly dispersed, and an alkaline substance is added and the mixture is uniformly dispersed to obtain a mixed suspension; the soluble metal salt is one of an iron salt and a nickel salt; wherein the mass ratio of the soluble cobalt salt, the soluble metal salt, the alkaline substance and the calcined zeolite is 1.07-1.6:0.25-2.1:0.5-3.6:1 (preferably 1.455-1.6:1.01-2.02:0.5-3.6:1, and particularly preferably 1.455:1.455:3.6:1);

[0010] (3) The mixed suspension described in step (2) is reacted at 75-95°C (preferably 80-90°C, particularly preferably 90°C) for 6-8 hours (preferably 7-8 hours, particularly preferably 8 hours), and the resulting reaction solution is post-treated to obtain the natural zeolite-based bimetallic layered silicate catalyst.

[0011] In one embodiment of the present invention, the particle size of the natural zeolite powder in step (1) is 0.5-100 μm.

[0012] Preferably, the volume of the deionized water in step (1) is 30-50 mL / g (preferably 30-40 mL / g, particularly preferably 30 mL / g) based on the mass of the calcined zeolite.

[0013] Preferably, the soluble metal salt in step (2) is a nickel salt.

[0014] In one embodiment of the present invention, the soluble cobalt salt is Co(NO3)2 6H2O, the nickel salt is Ni(NO3)2 6H2O, the iron salt is Fe(NO3)3 9H2O.

[0015] Preferably, the alkaline substance in step (2) is one or a mixture of two or more of urea, hexamethylenetetramine, and sodium hydroxide, and urea is particularly preferred.

[0016] Furthermore, the post-treatment in step (3) is as follows: cooling the reaction solution to room temperature, filtering, washing the obtained filter cake with deionized water and ethanol in sequence, and drying to obtain the natural zeolite-based bimetallic layered silicate catalyst.

[0017] The present invention also provides a method for preparing a natural zeolite-based bimetallic layered silicate catalyst. The resulting natural zeolite-based bimetallic layered silicate catalyst fully utilizes the high specific surface area of ​​the zeolite powder particles to form a layered silicate coating on the surface of the zeolite powder particles. The layered silicate has a nanotubular morphology. A representative reaction process is as follows:

[0018] CO(NH2)2 + 3H2O CO2 + 2(NH3·H2O) (>70°C)

[0019] NH3·H2O NH4 + +OH -

[0020] SiO2 (from zeolite decomposition) + 2OH - SiO3 2- +H2O

[0021] 3Co 2+ +2SiO3 2- + 2OH - +H2O Co3Si2O5(OH)4

[0022] When treating organic wastewater, the bimetallic layered silicate catalyst based on natural zeolite can use an adsorption method to treat organic pollutants in the water, or can use an advanced oxidation method represented by activated persulfate to treat organic pollutants in the water.

[0023] In a second aspect, the present invention also provides the use of the natural zeolite-based bimetallic layered silicate catalyst in treating organic pollutant wastewater.

[0024] Furthermore, the organic pollutant in the organic pollutant wastewater is at least one of norfloxacin, tetracycline, sulfamethoxazole, bisphenol A, perfluorinated compounds, pesticide compounds, and polycyclic aromatic hydrocarbons.

[0025] Specifically, the application is: uniformly dispersing the natural zeolite-based bimetallic layered silicate catalyst into organic pollutant wastewater for degradation for 30-60 minutes.

[0026] Furthermore, the concentration of organic pollutants in the organic pollutant wastewater is 5-100 mg / L; the mass volume ratio of the natural zeolite-based bimetallic layered silicate catalyst to the organic pollutant wastewater is 0.5-20 g: 1L.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The natural zeolite used as the raw material of the present invention has large natural reserves and is relatively cheap. The preparation method has low equipment requirements, the synthesis process is simple, the energy consumption is low, and the atmospheric pressure operation is convenient for large-scale production.

[0029] (2) In the bimetallic layered silicate catalyst based on natural zeolite provided by the present invention, the bimetallic layered silicate is uniformly coated on the surface of the zeolite in a nano-tubular structure, and the zeolite particles provide a dispersion carrier for the nano-tubular structure bimetallic layered silicate.

[0030] (3) In the bimetallic layered silicate catalyst based on natural zeolite provided by the present invention, the silicon source required for synthesizing the bimetallic layered silicate is provided by the zeolite.

[0031] (4) In the preparation method of the natural zeolite-based bimetallic layered silicate catalyst provided by the present invention, the catalytic performance of the prepared natural zeolite-based bimetallic layered silicate catalyst can be significantly improved by calcining the natural zeolite.

[0032] (5) In the preparation method of the bimetallic layered silicate catalyst based on natural zeolite provided by the present invention, the bimetallic may be a cobalt-nickel (Co / Ni) bimetallic or a cobalt-iron (Co / Fe) bimetallic.

[0033] (6) In the preparation method of the bimetallic layered silicate catalyst based on natural zeolite provided by the present invention, urea, hexamethylenetetramine or sodium hydroxide is used as a pH regulator, which can react with zeolite to provide silicate and promote the formation of layered silicate.

[0034] (7) In the preparation method of the natural zeolite-based bimetallic layered silicate catalyst provided by the present invention, the natural zeolite-based bimetallic layered silicate catalyst provided has an advanced oxidation catalytic degradation effect on organic pollutants in sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the XRD pattern of the bimetallic layered silicate catalyst based on natural zeolite in Example 1.

[0036] Figure 2 TEM image of the bimetallic layered silicate catalyst based on natural zeolite in Example 1.

[0037] Figure 3 This is a TEM image of the natural zeolite-based bimetallic layered silicate catalyst in Example 1 at high magnification.

[0038] Figure 4 This is the XRD pattern of the sample prepared in Comparative Example 4. DETAILED DESCRIPTION

[0039] Example 1

[0040] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 600 °C for 2 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0041] (2) Take 2 g of calcined zeolite calcined at 600 ° C, place it in 60 mL of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0042] (3) Add 2.91g Ni(NO3)2 to the mixture. 6H2O and 2.91g Co(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0043] (4) Weigh 7.2 g of urea and dissolve it in the mixed suspension B in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0044] (5) The mixed suspension C was transferred into a normal pressure water bath and reacted with magnetic stirring at 90°C for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain a nickel-cobalt bimetallic layered silicate catalyst based on natural zeolite.

[0045] The XRD pattern of the natural zeolite-based nickel-cobalt bimetallic layered silicate catalyst is shown in Figure 2. Figure 1 As shown, Figure 1 The results show that the crystal phase components of the sample include nickel layered silicate (Ni3Si2O5(OH)4), cobalt layered silicate (Co3Si2O5(OH)4) and quartz (SiO2).

[0046] The TEM image of the bimetallic layered silicate catalyst based on natural zeolite is shown in FIG. Figure 2 and Figure 3 As shown, Figure 2 It shows that the zeolite surface has obvious nickel-cobalt bimetallic layered silicate coating, which is evenly distributed on the zeolite surface and the coating is uniform overall. Figure 3 It shows that the nickel-cobalt bimetallic layered silicate catalyst generated on the zeolite surface has a tubular nanostructure.

[0047] Example 2

[0048] (1.) Weigh 10 g of natural zeolite powder (natural zeolite produced in Guangxi Zhuang Autonomous Region, ground to a powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 600°C for 2 h at a heating rate of 5°C / min to obtain calcined natural zeolite.

[0049] (2.) Take 2 g of calcined zeolite calcined at 600°C, place it in 60 mL of deionized water, and stir ultrasonically to disperse it evenly to obtain suspension A.

[0050] (3.) Then add 2.91 g Co(NO3)2 to the mixture. 6H2O, 4.04 g Fe(NO3)3 9H2O was stirred magnetically for 10 min to obtain a mixed suspension B.

[0051] (4.) Weigh 7.2 g of urea and dissolve it in the mixed suspension B prepared in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0052] The mixture was stirred in a water bath at atmospheric pressure at 90°C for 8 h, and then filtered. The filter cake was washed with deionized water and ethanol, and dried in vacuo at 60°C to obtain a bimetallic layered silicate catalyst based on natural zeolite.

[0053] Example 3

[0054] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5 to 100 μm) and calcine it in a tube furnace at 650 °C for 2 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0055] (2) Take 2 g of calcined zeolite calcined at 650 °C, place it in 60 mL of deionized water, and stir ultrasonically to disperse it evenly to obtain suspension A.

[0056] (3) Add 2.91 g Co(NO3)2 to the mixture 6H2O, 1.01 g Fe(NO3)3 9H2O was stirred magnetically for 10 min to obtain a mixed suspension B.

[0057] (4) Weigh 6.5 g of urea and dissolve it in the mixed suspension B prepared in step (3). Stir the mixture under ultrasonication for 10 min to obtain a mixed suspension C.

[0058] The mixture was stirred in a water bath at atmospheric pressure at 95°C for 6 h, and then filtered. The filter cake was washed with deionized water and ethanol, and dried in vacuo at 60°C to obtain a bimetallic layered silicate catalyst based on natural zeolite.

[0059] Example 4

[0060] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 700 °C for 3 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0061] (2) Take 2 g of calcined zeolite calcined at 700 °C, place it in 80 mL of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0062] (3) Add 2.318g Co(NO3)2 to the mixture. 6H2O and 1.455g Ni(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0063] (4) Weigh 1 g of sodium hydroxide (NaOH) and dissolve it in the mixed suspension B prepared in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0064] (5) The mixed suspension C was transferred into a normal pressure water bath and reacted with magnetic stirring at 80°C for 6 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol and filtered three times. It was vacuum dried at 60°C for 6 hours to obtain a bimetallic layered silicate catalyst based on natural zeolite.

[0065] Example 5

[0066] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 600 °C for 4 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0067] (2) Take 2 g of calcined zeolite calcined at 600 ° C, place it in 100 mL of deionized water, and stir ultrasonically to disperse it evenly to obtain suspension A.

[0068] (3) Add 3.201g Co(NO3)2 to the mixture. 6H2O and 2.02g Fe(NO3)3 9H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0069] (4) Weigh 8 g of hexamethylenetetramine and dissolve it in the mixed suspension B in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0070] (5) The mixed suspension C was transferred into a normal pressure water bath and reacted with magnetic stirring at 95°C for 7 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain a bimetallic layered silicate catalyst based on natural zeolite.

[0071] Example 6

[0072] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 700 °C for 3 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0073] (2) Take 2 g of calcined zeolite calcined at 700 °C, place it in 70 mL of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0074] (3) Add 2.91g Co(NO3)2 to the mixture. 6H2O and 0.582g Ni(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0075] (4) Weigh 1 g of sodium hydroxide (NaOH) and dissolve it in the mixed suspension B prepared in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0076] (5) The mixed suspension C was transferred into a normal pressure water bath and reacted with magnetic stirring at 90°C for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain a bimetallic layered silicate catalyst based on natural zeolite.

[0077] Comparative Example 1

[0078] (1) Weigh an appropriate amount of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5~100μm) and calcine it in a tube furnace at 600℃ for 2h at a heating rate of 5℃ / min to obtain calcined zeolite.

[0079] (2) Take 2 g of zeolite calcined at 600 ° C, place it in 60 ml of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0080] (3) Add 2.91g Ni(NO3)2 to suspension A. 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0081] (4) Weigh 7.2 g of urea and dissolve it in the mixed suspension B in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0082] (5) The mixed suspension C was transferred into a normal pressure water bath at 90°C and magnetically stirred for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain the sample of Comparative Example 1.

[0083] Comparative Example 1 Compared with Example 1, only Ni(NO3)2 was used in Comparative Example 1. 6H2O soluble metal salts.

[0084] Comparative Example 2

[0085] (1) Take 2 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region, and after grinding, the powder has a particle size distribution of 0.5~100 μm), place it in 60 mL of deionized water, and stir ultrasonically to disperse it evenly to obtain suspension A.

[0086] (2) Add 2.91g Ni(NO3)2 to the mixture. 6H2O and 2.91g Co(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0087] (3) Weigh 7.2 g of urea and dissolve it in the solution prepared in step (2). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0088] (4) The mixed suspension C was transferred into a normal pressure water bath at 90°C and reacted with magnetic stirring for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain the comparative example 2 sample.

[0089] Comparative Example 2 Compared with Example 1, the natural zeolite in Comparative Example 2 was not subjected to the calcination step.

[0090] Comparative Example 3

[0091] (1) Weigh an appropriate amount of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5~100μm) and calcine it in a tube furnace at 600℃ for 2h at a heating rate of 5℃ / min to obtain calcined natural zeolite.

[0092] (2) Take 3 g of natural zeolite calcined at 600 ° C, place it in 30 ml of 3 mol / L HCl solution, and magnetically stir it in an 80 ° C water bath for 8 hours to obtain a mixed solution containing acid-leached natural zeolite. After cooling to room temperature, wash and filter it three times with deionized water and ethanol, and vacuum dry it at 60 ° C for 6 hours to obtain acid-leached calcined zeolite.

[0093] (3) Take 2 g of acid-leached calcined zeolite powder, place it in 60 mL of deionized water, and stir ultrasonically to disperse it evenly to obtain suspension A.

[0094] (4) Add 2.91g Ni(NO3)2 to the mixture. 6H2O and 2.91g Co(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0095] (5) Weigh 7.2 g of urea and dissolve it in the solution prepared in step (2), stirring it ultrasonically for 10 min to obtain a mixed suspension C.

[0096] (5) The mixed suspension C was transferred into a water bath and reacted at 90°C for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 hours to obtain the comparative example 3 sample.

[0097] Comparative Example 3 Compared with Example 1, in Comparative Example 3, the calcined zeolite was acid leached.

[0098] Comparative Example 4

[0099] (1) Weigh 10 g of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5-100 μm) and calcine it in a tube furnace at 600 °C for 2 h at a heating rate of 5 °C / min to obtain calcined natural zeolite.

[0100] (2) Take 2 g of calcined zeolite calcined at 600 ° C, place it in 60 mL of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0101] (3) Add 2.91g Ni(NO3)2 to the mixture. 6H2O and 2.91g Co(NO3)2 6H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0102] (4) Weigh 7.2 g of urea and dissolve it in the mixed suspension B in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0103] (5) The mixed suspension C was transferred into a hydrothermal reactor and reacted at 140°C for 8 h. After cooling to room temperature, the mixture was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60°C for 6 h to obtain the sample of Comparative Example 4.

[0104] Compared with Example 1, the reaction temperature in Comparative Example 4 is 140°C. Figure 4 The XRD pattern of the sample prepared in comparative example 4 is shown. Figure 4 The results show that the crystal phase components of the sample include nickel basic carbonate, cobalt carbonate and quartz phases; no obvious nickel-cobalt bimetallic layered silicate formation was observed, indicating that the reaction temperature has an effect on the nickel-cobalt bimetallic layered silicate.

[0105] Comparative Example 5

[0106] 0.5 g of Example 1 was weighed and calcined in a tube furnace at 500° C. for 2 h at a heating rate of 5° C. / min to obtain a sample of Comparative Example 5.

[0107] Comparative Example 6

[0108] 0.5% of Example 1 was placed in 100 mL of 3 mol / L sodium hydroxide (NaOH) solution for reaction, stirred at 90° C. for 3 h, allowed to stand, centrifuged, washed with water until neutral, and vacuum dried to obtain a sample of Comparative Example 6.

[0109] Comparative Example 7

[0110] (1) Weigh an appropriate amount of natural zeolite powder (natural zeolite is produced in Guangxi Zhuang Autonomous Region and is ground into powder with a particle size distribution of 0.5~100μm) and calcine it in a tube furnace at 600℃ for 2h at a heating rate of 5℃ / min to obtain calcined zeolite.

[0111] (2) Take 2 g of zeolite calcined at 600 ° C, place it in 60 ml of deionized water, and stir it ultrasonically to disperse it evenly to obtain suspension A.

[0112] (3) Add 4.04g Fe(NO3)3 to suspension A. 9H2O was ultrasonically stirred for 10 min to obtain a mixed suspension B.

[0113] (4) Weigh 7.2 g of urea and dissolve it in the mixed suspension B in step (3). Stir ultrasonically for 10 min to obtain a mixed suspension C.

[0114] (5) The mixed suspension C was transferred into a normal pressure water bath at 90 ° C and magnetically stirred for 8 hours. After cooling to room temperature, it was filtered. The filter cake was washed with deionized water and ethanol three times and vacuum dried at 60 ° C for 6 hours to obtain the sample of comparative example 7.

[0115] Comparative Example 7 Compared with Example 1, only Fe(NO3)3 was used in Comparative Example 7. 9H2O soluble metal salts.

[0116] Application comparison experiment

[0117] 50 mL of an aqueous solution of norfloxacin (NFA) with an initial concentration of 20 mg / L was prepared to simulate organic pollutant wastewater. 25 mg of each sample prepared in Examples 1-6 and Comparative Examples 1-5 was added to the NFA solution with ultrasonic stirring. 25 mg of potassium persulfate (PMS) was added and allowed to react for a period of time. 3 mL of the solution was then sampled for solid-liquid separation. The residual NFA concentration in the solution was then measured, and the NFA adsorption and degradation rates of the samples were calculated. The experimental results are shown in Table 1.

[0118] Table 1 Adsorption catalytic degradation effect of examples and comparative examples on organic pollutants

[0119]

[0120] 1. As illustrated in Examples 1-3, the bimetallic layered silicate catalyst based on natural zeolite in the above examples has a degradation rate of more than 93% for norfloxacin solution in 60 minutes, indicating that the bimetallic layered silicate catalyst prepared in the examples of the present invention has excellent catalytic performance.

[0121] 2. As illustrated in Examples 1-6, the natural zeolite-based bimetallic layered silicate catalysts prepared in the above examples using urea, hexamethylenetetramine, and NaOH as alkaline substances all have good catalytic performance for norfloxacin solution, among which the sample prepared using urea as the preferred alkaline substance has better catalytic performance.

[0122] 3. Examples 1-6 illustrate that the catalytic performance of the natural zeolite-based bimetallic layered silicate catalysts obtained by changing the type of raw materials, ratio, reaction temperature, and time in the above examples varies. The sample prepared in Example 1 has a degradation rate of 95.70% for norfloxacin solution in 60 minutes.

[0123] 4. The degradation rates of Example 1 and Comparative Example 1 show that the addition of nickel and cobalt bimetallic salts will increase the degradation rate of the cobalt-nickel bimetallic layered silicate catalyst for norfloxacin solution.

[0124] 5. The degradation rates of Example 1 and Comparative Example 2 indicate that calcining natural zeolite can increase the degradation rate of norfloxacin solution by the cobalt-nickel bimetallic layered silicate catalyst.

[0125] 6. The degradation rates of Example 1 and Comparative Example 3 indicate that acid leaching of calcined zeolite reduces the degradation rate of norfloxacin solution by the cobalt-nickel bimetallic layered silicate catalyst.

[0126] 7. The degradation rates of Example 1 and Comparative Example 4 indicate that increasing the reaction temperature will reduce the degradation rate of the cobalt-nickel bimetallic layered silicate catalyst for norfloxacin solution.

[0127] 8. The degradation rates of Example 1 and Comparative Examples 5 and 6 indicate that calcining the prepared cobalt-nickel bimetallic layered silicate catalyst at high temperature or reacting it in a NaOH solution can reduce the degradation rate of the sample to norfloxacin solution.

[0128] 9. The degradation rates of Example 2 and Comparative Example 7 show that the addition of iron and cobalt bimetallic salts will increase the degradation rate of norfloxacin solution by the iron-cobalt bimetallic layered silicate catalyst.

Claims

1. Application of a bimetallic layered silicate catalyst based on natural zeolite in treating organic pollutant wastewater, characterized in that The bimetallic layered silicate catalyst based on natural zeolite is prepared as follows: (1) Natural zeolite powder with a particle size of 0.2 to 200 μm is calcined at 300 to 700°C for 2 to 4 hours to obtain calcined zeolite; (2) The calcined zeolite described in step (1) is uniformly dispersed in deionized water, a soluble cobalt salt and a soluble metal salt are added, and the mixture is uniformly dispersed, and an alkaline substance is added and the mixture is uniformly dispersed to obtain a mixed suspension; the soluble metal salt is one of an iron salt and a nickel salt; wherein the mass ratio of the soluble cobalt salt, the soluble metal salt, the alkaline substance and the calcined zeolite is 1.07-1.6:0.25-2.1:0.5-3.6:1; (3) The mixed suspension described in step (2) is reacted at 75-95° C. for 6-8 hours, and the obtained reaction solution is post-treated to obtain the bimetallic layered silicate catalyst based on natural zeolite.

2. The use of the natural zeolite-based bimetallic layered silicate catalyst according to claim 1, characterized in that: The volume of the deionized water in step (2) is 30-50 mL / g based on the mass of the calcined zeolite.

3. The use of the natural zeolite-based bimetallic layered silicate catalyst according to claim 1, characterized in that: The soluble metal salt described in step (2) is a nickel salt.

4. The use of the natural zeolite-based bimetallic layered silicate catalyst according to claim 1, characterized in that: The alkaline substance in step (2) is one or a mixture of two or more of urea, hexamethylenetetramine, and sodium hydroxide.

5. The use of the natural zeolite-based bimetallic layered silicate catalyst according to claim 1, characterized in that: In step (2), the soluble cobalt salt is Co(NO3)2•6H2O, the nickel salt is Ni(NO3)2•6H2O, and the iron salt is Fe(NO3)3•9H2O.

6. The use of the natural zeolite-based bimetallic layered silicate catalyst according to claim 1, characterized in that: The post-treatment in step (3) is as follows: cooling the reaction solution to room temperature, filtering, washing the obtained filter cake with deionized water and ethanol in sequence, and drying to obtain the natural zeolite-based bimetallic layered silicate catalyst.

7. Use of the natural zeolite-based bimetallic layered silicate catalyst according to any one of claims 1 to 6 in treating organic pollutant wastewater, characterized in that: The organic pollutant in the organic pollutant wastewater is at least one of norfloxacin, tetracycline, sulfamethoxazole, bisphenol A, perfluorinated compounds, and polycyclic aromatic hydrocarbons.

8. The use according to any one of claims 1 to 6, characterized in that The application is: uniformly dispersing the bimetallic layered silicate catalyst based on natural zeolite into organic pollutant wastewater for degradation for 30-60 minutes.

9. The use according to any one of claims 1 to 6, characterized in that: The concentration of organic pollutants in the organic pollutant wastewater is 5-100 mg / L; the mass volume ratio of the natural zeolite-based bimetallic layered silicate catalyst to the organic pollutant wastewater is 0.5-20 g: 1L.

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