Red mud-based catalyst as well as preparation method and application thereof

Abstract

The invention provides a red mud-based catalyst and a preparation method and application thereof, the red mud-based catalyst comprises red mud and a perovskite composite material, the general formula of the perovskite composite material is LaCoxNi (1-x) O (3-y), 0 < x < 1, 0 lt, 0 < y < 1, 0 lt, 0 < y < 1, 0 < y < 1, 0 < y < 1, 0 < y < 1, 0 < y < 1, 0 < y < 1, 0 < y < Yt; Yt; and y represents oxygen vacancy. The red mud-based catalyst provided by the invention has the advantages of low cost, strong environmental adaptability, strong stability and reusability.

Description

Technical Field

[0001] The present invention relates to a red mud-based catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Red mud (RM) is an extremely fine and strongly alkaline solid waste generated during the production of alumina from bauxite. In China, it belongs to Class II general industrial solid waste and has a certain harmful effect on the environment. At present, the main disposal method for red mud is stacking and covering with soil. A large amount of stacking causes waste of land resources and restricts the development of the aluminum industry. Moreover, the residual value of red mud has not been fully utilized, resulting in a large amount of resource idle waste. Therefore, reducing the harm of red mud to the environment and improving the utilization rate of red mud are effective means to achieve the sustainable development of the alumina industry.

[0003] More than 90% of the particles of red mud have a particle size of 50 - 75 μm, and it has the characteristics of fine particles and good dispersion. Red mud particles have the characteristics of high surface activity and strong adsorption ability. And its internal structure is porous, with a porosity of 2.53 - 2.95, having excellent adsorption ability and ion exchange ability. Therefore, RM is an ideal catalyst carrier, and the Fe and other metals and rare earth elements such as lanthanide elements it contains provide the possibility for the application of red mud in the catalytic field. Summary of the Invention

[0004] To solve the above problems, the present invention provides a red mud-based catalyst, a preparation method thereof, and an application thereof. The red mud-based catalyst has low cost, strong environmental adaptability, strong stability, and can be reused.

[0005] In the first aspect of the present invention, a red mud-based catalyst is provided. The red mud-based catalyst includes red mud and a perovskite composite material. The general formula of the perovskite composite material is LaCo x Ni 1-x O 3-y , where 0 < x < 1, 0 < y < 3, and y represents the oxygen vacancy content.

[0006] Perovskite-based oxides (ABO3) are effective catalysts for peroxymonosulfate (PMS) and can effectively degrade organic matter in water. Recent studies have shown that by doping or introducing different foreign metal oxygen ions at the B site, oxygen vacancies can be introduced while maintaining the perovskite's spatial configuration, thereby enhancing the catalytic activity of the perovskite. Furthermore, a stable chemical bond can be formed between the two metals, effectively inhibiting metal dissolution and improving the stability of the catalyst. The advantages of red mud's large porosity and strong adsorption capacity may further enhance pollutant removal. Furthermore, the various metal ions contained in red mud, such as Fe, Al, and Ti, can serve as B-site doping elements, promoting the formation of oxygen vacancies and significantly increasing the number of active sites in the catalyst. Furthermore, the presence of bauxite, iron oxides, ilmenite, silicate minerals, and calcium minerals in red mud may enhance the stability and mechanical strength of the perovskite, improving its durability and reusability in catalytic reactions. The inventors of this application have discovered that by combining the advantages of these two materials, a pathway for rapid red mud adsorption and perovskite degradation can be achieved to accelerate pollutant degradation.

[0007] In some embodiments, x can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or any value therebetween.

[0008] In some embodiments, 0.2≤x≤0.8.

[0009] In some embodiments, 0.4≤x≤0.6.

[0010] In some embodiments, in the red mud-based catalyst, the red mud includes bauxite, iron oxide, ilmenite, silicate minerals and calcium minerals.

[0011] In some embodiments, in the red mud-based catalyst, the red mud includes SiO2, Al2O3, Fe2O3 and CaO.

[0012] In some embodiments, in the mud-based catalyst, the mass ratio of the Al element in the red mud to the Ni element and the Co element in the perovskite composite material is (30-95): (30-70): (20-40), for example, 30: (30-70): (20-40), 40: (30-70): (20-40), 50: (30-70): (20-40), 60: (30-70): (20-40), 70: (30-70): (20-40), 80: (30-70): (20-40), 90: (30-70): (20-40), and 100: (30-70): (20-40). or any value in between.

[0013] A second aspect of the present invention provides a method for preparing a red mud-based catalyst, comprising the following steps:

[0014] (1) mixing red mud, a La-containing ion compound, a Co-containing ion compound, and a Ni-containing ion compound in a solvent to obtain a homogeneous mixed solution;

[0015] (2) adjusting the pH of the homogeneous mixed solution to alkaline to obtain an alkaline homogeneous mixed solution;

[0016] (3) heat-treating the alkaline homogeneous mixed solution.

[0017] According to some embodiments of the preparation method of the present invention, in step (1), the water content of the red mud is ≤5%, such as 5%, 4%, 3%, 2%, 1%, or 0.8%.

[0018] According to some embodiments of the preparation method of the present invention, the fineness of the red mud is 10-200 mesh, such as 10 mesh, 50 mesh, 80 mesh, 100 mesh, 120 mesh, and 200 mesh.

[0019] According to some embodiments of the preparation method of the present invention, the red mud includes bauxite, iron oxide, ilmenite, silicate minerals and calcium minerals.

[0020] In some embodiments, the red mud includes SiO2, Al2O3, Fe2O3, and CaO.

[0021] According to some embodiments of the preparation method of the present invention, the La-containing ion compound is selected from La(NO3)3 or its hydrate, LaCl3 or its hydrate, La2(SO4)3 or its hydrate.

[0022] According to some embodiments of the preparation method of the present invention, the Co-containing ion compound is selected from Co(NO3)2 or its hydrate, CoCl2 or its hydrate, CoSO4 or its hydrate.

[0023] According to some embodiments of the preparation method of the present invention, the Ni ion-containing compound is selected from Ni(NO3)2 or its hydrate, NiCl2 or its hydrate, NiSO4 or its hydrate.

[0024] According to some embodiments of the preparation method of the present invention, the solvent is ultrapure water.

[0025] According to some embodiments of the preparation method of the present invention, in step (2), the pH of the homogeneous mixed solution is adjusted using an alkaline solution.

[0026] According to some embodiments of the preparation method of the present invention, the alkaline solution is selected from NaOH aqueous solution.

[0027] According to some embodiments of the preparation method of the present invention, the concentration of NaOH in the NaOH aqueous solution is 0.5-2 M, for example, 0.5 M, 0.7 M, 0.9 M, 1.1 M, 1.3 M, 1.5 M, 1.7 M, 1.9 M or any value therebetween.

[0028] According to some embodiments of the preparation method of the present invention, the pH is 10-15, for example, 10, 11, 12, 13, 14, 15 or any value therebetween.

[0029] According to some embodiments of the preparation method of the present invention, the molar ratio of the total molar amount of the Co element in the Co-containing ion compound and the Ni element in the Ni-containing ion compound to the La element in the La-containing ion compound is 1:1.

[0030] According to some embodiments of the preparation method of the present invention, the molar ratio of the Co element in the Co-containing ion compound to the Ni element in the Ni-containing ion compound is (0.25-4):1, such as 0.25:1, 0.5:1, 0.75:1, 1:1, 1.5:1, 2:1, 3:1, and 4:1.

[0031] According to some embodiments of the preparation method of the present invention, the molar ratio of the La element in the La-containing ion compound to the Ni element in the Ni-containing ion compound is 1:(0.2-0.8), such as 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, and 1:0.8.

[0032] According to some embodiments of the preparation method of the present invention, the molar ratio of the total molar sum of the Co element in the Co-containing ion compound and the Ni element in the Ni-containing ion compound to the La element in the La-containing ion compound is 1:1, and the molar ratio of the Co element in the Co-containing ion compound to the Ni element in the Ni-containing ion compound is (0.25-4):1, and the molar ratio of the La element in the La-containing ion compound to the Ni element in the Ni-containing ion compound is 1:(0.2-0.8).

[0033] According to some embodiments of the preparation method of the present invention, the mass ratio of the La-containing ion compound to red mud is 1:(0.1-10), such as 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:0.9, 1:1, 1:2, 1:4, 1:5, 1:6, 1:8, 1:10 or any value therebetween.

[0034] According to some embodiments of the preparation method of the present invention, the mass ratio of the La-containing ion compound to the red mud is 1:(0.1-5).

[0035] According to some embodiments of the preparation method of the present invention, the mass ratio of the La-containing ion compound to the red mud is 1:(0.1-1).

[0036] According to some embodiments of the preparation method of the present invention, the heat treatment step comprises:

[0037] S1, performing a first heat treatment on the homogeneous mixed liquid, filtering, and drying to obtain a solid;

[0038] S2, performing a second heat treatment on the solid.

[0039] According to some embodiments of the preparation method of the present invention, the first heat treatment is performed in a heat-collecting constant-temperature oil bath.

[0040] According to some embodiments of the preparation method of the present invention, the second heat treatment is performed in a tube furnace.

[0041] According to some embodiments of the preparation method of the present invention, the temperatures of the first heat treatment and the second heat treatment are each independently 700-1000°C; for example, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C or any value therebetween.

[0042] According to some embodiments of the preparation method of the present invention, the time of the first heat treatment and the second heat treatment are each independently 1-5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours or any value therebetween.

[0043] According to some embodiments of the preparation method of the present invention, the heating rate of the second heat treatment is 1-5°C / min, for example, 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min or any value therebetween.

[0044] According to some embodiments of the preparation method of the present invention, after the first heat treatment, the filter cake is cooled to 20-30° C., solid-liquid separation is performed, and then the filter cake is washed and dried.

[0045] According to some embodiments of the preparation method of the present invention, solid-liquid separation can be carried out by filtration, centrifugation, etc.

[0046] According to some embodiments of the preparation method of the present invention, the washing uses deuterium-depleted water (ddw) and anhydrous ethanol.

[0047] According to some embodiments of the preparation method of the present invention, the drying is performed in a forced air dryer.

[0048] The third aspect of the present invention provides a use of the red mud-based catalyst described in the first aspect of the present invention or the red mud-based catalyst described in the second aspect of the present invention in treating antibiotic-containing wastewater.

[0049] According to some embodiments of the use of the present invention, the organic matter is selected from antibiotics.

[0050] According to some embodiments of the use of the present invention, the organic matter is selected from one or more of sulfonamide antibiotics, quinolone antibiotics or tetracycline antibiotics.

[0051] According to some embodiments of the use of the present invention, the antibiotic is selected from one or more of sulfamethoxazole, levofloxacin, norfloxacin, ciprofloxacin or tetracycline hydrochloride.

[0052] In a fourth aspect of the present invention, a method for treating organic-containing wastewater is provided, comprising mixing the red mud-based catalyst described in the first aspect of the present invention or the red mud-based catalyst prepared by the second aspect of the present invention, persulfate, and organic-containing wastewater to degrade organic matter in the organic-containing wastewater.

[0053] According to some embodiments of the treatment method of the present invention, the organic matter is selected from antibiotics.

[0054] According to some embodiments of the treatment method of the present invention, the organic matter is selected from one or more of sulfonamide antibiotics, quinolone antibiotics or tetracycline antibiotics.

[0055] According to some embodiments of the treatment method of the present invention, the organic matter is selected from one or more of sulfamethoxazole, levofloxacin, norfloxacin, ciprofloxacin or tetracycline hydrochloride.

[0056] According to some embodiments of the treatment method of the present invention, the organic matter content in the organic-containing wastewater is 10-50 mg / L, for example, 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L or any value therebetween.

[0057] According to some embodiments of the treatment method of the present invention, the persulfate is selected from peroxymonosulfate (PMS) and / or peroxydisulfate (PDS).

[0058] According to some embodiments of the treatment method of the present invention, the amount of the red mud-based catalyst is 0.01-1 g / L, for example, 0.01 g / L, 0.05 g / L, 0.10 g / L, 0.2 g / L, 0.4 g / L, 0.6 g / L, 0.8 g / L, 1 g / L or any value therebetween.

[0059] According to some embodiments of the treatment method of the present invention, the amount of persulfate used is 0.1-5 mM, for example, 0.1 mM, 0.5 mM, 1 mM, 1.5 mM, 2 mM, 2.5 mM, 3 mM, 3.5 mM, 4 mM, 5 mM or any value therebetween.

[0060] According to some embodiments of the treatment method of the present invention, the amount of persulfate used is 2-4 mM.

[0061] According to some embodiments of the treatment method of the present invention, when the content of antibiotics in the antibiotic-containing wastewater is 20 mg / L, the dosage of the catalyst is 0.05-0.8 g / L, such as 0.05 g / L, 0.10 g / L, 0.20 g / L, 0.40 g / L, 0.60 g / L, and 0.80 g / L.

[0062] According to some embodiments of the treatment method of the present invention, when the content of antibiotics in the antibiotic-containing wastewater is 20 mg / L, the dosage of the PMS is 0.5-4 mM, such as 0.5 mM, 1 mM, 2 mM, 3 mM, and 4 mM.

[0063] According to some embodiments of the treatment method of the present invention, the degradation temperature is 15-30°C, for example, 15°C, 18°C, 21°C, 24°C, 27°C, 30°C or any value therebetween.

[0064] According to some embodiments of the treatment method of the present invention, the degradation time is 30-80 min, for example, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or any value therebetween.

[0065] According to some embodiments of the treatment method of the present invention, the pH of the organic-containing wastewater is 3-11, for example, 3, 5, 7, 9, 11 or any value therebetween.

[0066] The beneficial effects of the present invention are: the red mud-based catalyst of the present invention is low-cost, highly environmentally adaptable, stable, and reusable. The catalyst is universally applicable and highly efficient in treating antibiotic-contaminated water, achieving the dual effects of waste utilization and pollution removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is the XRD pattern of the catalyst described in Example 1 of the present invention;

[0068] Figure 2 This is a SEM image of the catalyst described in Example 1 of the present invention;

[0069] Figure 3 This is a TEM structure diagram of the catalyst described in Example 1 of the present invention;

[0070] Figure 4 This is a STEM-EDS image of the catalyst described in Example 1 of the present invention;

[0071] Figure 5 This is a diagram showing the degradation effect of the catalyst described in Example 1 of the present invention on TOC in winery wastewater. DETAILED DESCRIPTION

[0072] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the following embodiments and accompanying drawings. The specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention in any way. In addition, descriptions of known structures and techniques are omitted in the following description to avoid unnecessary confusion regarding the concepts of the present disclosure. Such structures and techniques are also described in many publications.

[0073] Normal temperature and room temperature in the present invention refer to 20-40°C.

[0074] 2KHSO5·KHSO4·K2SO4, Na2S2O3, Co(NO3)2·6H2O, La(NO3)3·6H2O), 99.5%, Ni(NO3)2·6H2O), 99.5%, NaOH, HCl, sulfamethoxazole (SMX), levofloxacin (LFX), norfloxacin (NFX), ciprofloxacin (CIP), tetracycline hydrochloride (TC), NaCl, NaHCO3, NaH2PO4, Na2SO4, and NaNO3 used in the examples and comparative examples of the present invention were all purchased from Aladdin.

[0075] The red mud used in the examples and comparative examples of this application was collected from a red mud dump. The fresh red mud was naturally air-dried, ground into powder, passed through a 100-mesh sieve, and sealed for future use. The water content of the collected red mud was ≤5%.

[0076] The XRF results of the red mud (RM) components are shown in Table 1:

[0077] Table 1

[0078]

[0079] Example 1 Preparation of catalyst

[0080] 0.4330 g of La(NO₃)₃·6H₂O, 0.1455 g of Co(NO₃)₂·6H₂O, 0.1353 g of Ni(NO₃)₂·6H₂O (molar ratio of 1:0.5:0.5), and 0.880 g of RM (mass ratio of RM to La(NO₃)₃·6H₂O of 1:0.5) were placed in a three-necked flask filled with 250 mL of ultrapure water. After homogenization by ultrasonic treatment for 30 minutes, the mixture was mechanically stirred at room temperature for 24 hours to obtain a homogenous solution. The pH of the homogenous solution was then adjusted to 12 using 1 M NaOH solution. The mixture was stirred at 800°C for 2 hours in a thermostatic oil bath with mechanical stirring (700 rpm). After cooling to room temperature, the sample was filtered, washed three times with ddW and anhydrous ethanol, and then dried overnight in a 70°C air dryer. After that, the filter cake was ground into powder and placed in a tube furnace for heat treatment at 800℃ for 2h with a temperature increase of 3℃ / min. After cooling to room temperature, the composite material RM / LaCo was obtained. 0.5 Ni 0.5 O 3-y .

[0081] The catalyst phase composition was analyzed by X-ray powder diffraction (XRD, Bruker D2 PHASER, Germany). Figure 1 As shown, from Figure 1 It can be seen that the XRD pattern of the material is similar to that of LaCo 0.5 Ni0.5 O 3-y The standard diffraction pattern (JCPDS No. 54-0834) is very consistent with the RM / LaCo 0.5 Ni 0.5 O 3-y The material exhibited strong diffraction peaks, indicating a high degree of crystallinity. Diffraction peaks appeared at 23.144°, 32.744°, 33.204°, 47.324°, and 58.763°, corresponding to the (012), (110), (104), (024), and (214) crystal planes, respectively.

[0082] The surface morphology of the synthesized catalysts was observed using a field emission scanning electron microscope (FESEM, JSM-7800F, Japan). Figure 2 .

[0083] The microscopic morphology of the prepared material can be observed using a transmission electron microscope (TEM). Figure 3 .

[0084] By determining the structure and element distribution characteristics of the catalyst material, the results are as follows Figure 4 STEM-EDS analysis revealed La, Co, Ni, Fe, Al, O, and Si on the material's surface. Fe, Al, and Si are present in red mud. The elemental distribution map shows that each element is evenly distributed on the material's surface, further demonstrating the successful preparation of the material.

[0085] Example 2 Preparation of catalyst

[0086] 0.4330 g of La(NO₃)₃·6H₂O, 0.1455 g of Co(NO₃)₂·6H₂O, 0.1353 g of Ni(NO₃)₂·6H₂O (molar ratio of 1:0.5:0.5), and 0.4330 g of RM (mass ratio of RM to La(NO₃)₃·6H₂O of 1:1) were placed in a three-necked flask filled with 250 mL of ultrapure water. After homogenization by ultrasonic treatment for 30 minutes, the mixture was mechanically stirred at room temperature for 30 hours to obtain a homogenous solution. The pH of the mixture was then adjusted to 12 using 1 M NaOH solution. The mixture was stirred at 800°C for 2 hours in a thermostatic oil bath with mechanical stirring (700 rpm). After cooling to room temperature, the sample was filtered and washed three times with ddW and anhydrous ethanol, respectively, before being dried overnight in a 70°C air dryer. After that, the filter cake was ground into powder and placed in a tube furnace for heat treatment at 800℃ for 2h with a temperature increase of 3℃ / min. After cooling to room temperature, the composite material RM / LaCo was obtained. 0.5 Ni 0.5 O 3-y .

[0087] Example 3 Preparation of catalyst

[0088] 0.4330 g of La(NO₃)₃·6H₂O, 0.1455 g of Co(NO₃)₂·6H₂O, 0.1353 g of Ni(NO₃)₂·6H₂O (molar ratio of 1:0.5:0.5), and 4.330 g of RM (mass ratio of La(NO₃)₃·6H₂O to RM of 1:10) were placed in a three-necked flask filled with 250 mL of ultrapure water. After homogenization by ultrasonic treatment for 30 minutes, the mixture was mechanically stirred at room temperature for 48 hours to obtain a homogenous solution. The pH of the homogenous solution was then adjusted to 12 using 1 M NaOH solution. The mixture was stirred at 800°C for 2 hours with mechanical stirring (700 rpm) in a thermostatic oil bath. After cooling to room temperature, the sample was filtered and washed three times with ddW and anhydrous ethanol, respectively, before being dried overnight in a 70°C air dryer. After that, the filter cake was ground into powder and placed in a tube furnace for heat treatment at 800℃ for 2h with a temperature increase of 3℃ / min. After cooling to room temperature, the composite material RM / LaCo was obtained. 0.5 Ni 0.5 O 3-y .

[0089] The catalysts obtained in Examples 1-3 above could only be tested to contain oxygen vacancies, but their specific content could not be determined. Therefore, RM / LaCo 0.5 Ni 0.5 O 3-y represents, and y represents the oxygen vacancy content.

[0090] 1. Catalyst performance test

[0091] To test the performance of a red mud-based catalyst for the degradation of environmental organic pollutants using PMS, this study selected the sulfonamide antibiotic sulfamethoxazole as the target pollutant for catalytic performance testing. All degradation experiments were conducted in 100 mL Erlenmeyer flasks placed on a horizontal shaker (OS-20Pro, JOANLAB, China). The solution was stirred at 100 rpm at room temperature for 40 minutes. First, a pre-weighed amount of the red mud-based catalyst and 50 mL of a pre-prepared solution of 20 mg / L of the target organic compound were added to the 100 mL Erlenmeyer flask. The pH of the solution was adjusted to the desired value using 1 M NaOH and 1 M HCl solutions. The pH of the solution was measured using a pH meter (ST3100, OHAUS, China). After 30 minutes of oscillation to reach adsorption equilibrium, an appropriate concentration of PMS was added to the flask to initiate the degradation reaction. At predetermined intervals, 1 mL of the solution was removed from the flask and added to a centrifuge tube containing 1 mL of 0.2 M Na2S2O3 solution. After filtering through a 0.22 μm organic syringe filter, the solution was added to a 2 mL liquid injection vial for subsequent analysis and determination. The concentration of SMX was determined using liquid chromatography (HPLC, 1800, Agilent, USA).

[0092] 1.1 Effect of different catalyst dosages on SMX degradation

[0093] The catalyst dosage and SMX degradation effect obtained in Example 1 are shown in Table 2:

[0094] Table 2

[0095]

[0096] It can be seen from Table 2 that the more the amount of catalyst used, the faster the reaction. However, considering the cost, the amount of catalyst used is preferably 0.4 g / L-0.6 g / L, more preferably 0.4 g / L.

[0097] 1.2 Effect of different PMS dosages on SMX degradation

[0098] The PMS dosage and SMX degradation effect are shown in Table 3:

[0099] Table 3

[0100]

[0101]

[0102] It can be seen from Table 3 that the more PMS is added, the faster the reaction is. However, considering the cost, the preferred amount of PMS is 3 mM.

[0103] 1.3 Effect of different pH values on SMX degradation during degradation

[0104] The pH value and the degradation effect of SMX are shown in Table 4:

[0105] Table 4

[0106]

[0107] From Table 4 we can see that: RM / LaCo 0.5 Ni 0.5 O 3-y The / PMS system is highly adaptable to the pH of the solution and can be completely degraded within 40 minutes in a pH range of 3-11. This means that the system is almost unaffected by the pH of environmental wastewater in practical applications and has a wide range of applications.

[0108] 1.4 Effect of anions contained in target pollutants on SMX degradation

[0109] Add 10 mM Cl to each target pollutant. - 、HCO3 - 、H2PO4 - 、SO4 2- 、NO3 - , the effect on the degradation of SMX is shown in Table 5:

[0110] Table 5

[0111]

[0112] From Table 5, we can see that although the anion has a certain degree of inhibition on the degradation of SMX, the degree of inhibition is H2PO4 - >HCO3 - >NO3 - >SO4 2- >Cl - However, each group achieved a degradation rate of more than 80% within 60 minutes.

[0113] 1.5 Degradation Effect of the Catalyst Described in Example 1 of the Present Application on Different Antibiotics

[0114] Table 6

[0115]

[0116] From Table 6, we can see that after 30 minutes of reaction, the removal rates of the four antibiotics can reach 94%. 0.5 Ni 0.5 O 3-y / The universality of the PMS system for different antibiotics.

[0117] 1.6 Stability and Reusability of the Catalyst Described in Example 1 of the Present Application

[0118] Table 7

[0119]

[0120] From Table 7, we can see that within 60 min, the degradation rates of the first use (CF-1), the second use (CF-2), and the third use (CF-3) are 100%, 96.90%, and 89.20%, respectively. 0.5 Ni 0.5 O 3-y The material has good reusability.

[0121] 1.7 Effect of the Catalyst Described in Example 1 of the Present Application on TOC Degradation in Winery Wastewater

[0122] Table 8

[0123]

[0124] From Table 8 and Figure 5 It can be seen that the catalyst has a degradation effect on TOC and can be used to degrade actual high-concentration organic wastewater.

[0125] The ecotoxicity of SMX and other identified intermediates was predicted using the Ecostructure-Activity Relationship (ECOSAR) model. Toxicity was assessed using three representative aquatic organisms: fish, Daphnia, and green algae. Based on our hypothesized pathways, nearly all of the products were non-toxic.

[0126] 1.8 Effect of different catalysts on SMX degradation

[0127] All degradation experiments were conducted in 100 mL Erlenmeyer flasks placed on a horizontal shaker (OS-20 Pro, JOANLAB, China). The solution was stirred at 100 rpm at room temperature for 40 min. First, the pre-weighed catalyst and 50 mL of a pre-prepared 20 mg / L target organic solution were added to the 100 mL Erlenmeyer flask. The pH of the solution was adjusted to the set value using 1 M NaOH solution and 1 M HCl solution. The pH of the solution was measured using a pH meter (ST3100, OHAUS, China). After 30 min of oscillation reaction to reach adsorption equilibrium, an appropriate concentration of PMS was added to the Erlenmeyer flask to stimulate the degradation reaction. At preset time intervals, 1 mL of the solution was removed from the Erlenmeyer flask and added to a centrifuge tube containing 1 mL of 0.2 M Na2S2O3 solution. After filtering using a 0.22 μm organic syringe filter, the solution was added to a 2 mL liquid phase injection vial for subsequent analysis. The concentration of SMX was determined by liquid chromatography (HPLC, 1800, Agilent, USA). The results are shown in Table 9.

[0128] Table 9

[0129]

[0130] Among them, Al is the element present in red mud, and the Al:Ni:Co mass ratio represents the synthetic mass ratio of Ni and Co in the red mud and perovskite composite material.

[0131] 1.9 Cost Calculation

[0132] Preparation of the catalyst described in this application (RM / LaCo 0.5 Ni 0.5 O 3-y The cost of the material is also one of the important factors in evaluating its future application prospects. Therefore, we investigated the market price of the raw materials (in tons) and calculated the cost of preparing 1kg RM / LaCo based on this. 0.5 Ni 0.5 O 3-y Cost of materials (ignoring factors such as electricity costs).

[0133] According to market prices, red mud is 0 yuan / kg; lanthanum nitrate is 11 yuan / kg, which is equivalent to 3.01 yuan / kg; cobalt nitrate hexahydrate is 70 yuan / kg, which is equivalent to 6.45 yuan / kg; nickel nitrate hexahydrate is 9 yuan / kg, which is equivalent to 0.15 yuan / kg; after conversion, 1kgRM / LaCo is prepared. 0.5 Ni 0.5 O 3-y Only 10.23 yuan. The price of common antibiotic catalysts on the market is in the range of 10-28 yuan / kg. 0.5Ni 0.5 O 3-y The cost price of the material is within the acceptable range of market fluctuations. In addition, the degradation efficiency of the material is high, and the amount of catalyst and oxidant required is small, which is more cost-effective than the catalysts on the market. Considering the economic cost, RM / LaCo 0.5 Ni 0.5 O 3-y It also has broad application prospects.

[0134] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A red mud-based catalyst comprising red mud and a perovskite composite material, wherein the general formula of the perovskite composite material is LaCo x Ni 1-x O 3-y ,in, 0 < x < 1, 0 < y < 3, where y represents the oxygen vacancy content.

2. The red mud-based catalyst according to claim 1, characterized in that 0.2 ≤ x ≤ 0.8, preferably, 0.4 ≤ x ≤ 0.

6.

3. The red mud-based catalyst according to claim 1 or 2, characterized in that in the red mud-based catalyst, the red mud includes bauxite, iron oxide, ilmenite, silicate minerals and calcium minerals; preferably, in the red mud-based catalyst, the red mud includes SiO2, Al2O3, Fe2O3 and CaO; preferably, in the red mud-based catalyst, the mass ratio of Al element in the red mud to Ni element and Co element in the perovskite composite material is (30 - 95):(30 - 70):(20 - 40).

4. A preparation method of a red mud-based catalyst, comprising the following steps: (1) Mix red mud, La ion-containing compound, Co ion-containing compound, and Ni ion-containing compound in a solvent to obtain a homogeneous mixture; (2) Adjust the pH of the homogeneous mixture to alkaline to obtain an alkaline homogeneous mixture; (3) Perform heat treatment on the alkaline homogeneous mixture.

5. The preparation method according to claim 4, characterized in that In step (1), the water content of the red mud ≤ 5%, and the fineness of the red mud is 10 - 200 mesh; preferably, the red mud includes bauxite, iron oxide, ilmenite, silicate minerals and calcium minerals; preferably, the red mud includes SiO2, Al2O3, Fe2O3 and CaO.

6. The preparation method according to claim 4 or 5, characterized in that The La ion-containing compound is selected from La(NO3)3 or its hydrate, LaCl3 or its hydrate, La2(SO4)3 or its hydrate; and / or, the Co ion-containing compound is selected from Co(NO3)2 or its hydrate, CoCl2 or its hydrate, CoSO4 or its hydrate; and / or, the Ni ion-containing compound is selected from Ni(NO3)2 or its hydrate, NiCl2 or its hydrate, NiSO4 or its hydrate; and / or, the solvent is ultrapure water; and / or, in step (2), the pH of the homogeneous mixture is adjusted with an alkali solution. Preferably, the alkali solution is selected from NaOH aqueous solution; preferably, the concentration of NaOH in the NaOH aqueous solution is 0.5 - 2M; preferably, the pH is 10 - 15.

7. The preparation method according to any one of claims 4 to 6, characterized in that The molar sum of Co element in the Co ion-containing compound and Ni element in the Ni ion-containing compound and the molar ratio of La element in the La ion-containing compound is 1:1; preferably, the molar ratio of Co element in the Co ion-containing compound to Ni element in the Ni ion-containing compound is (0.25 - 4):1; and / or, the molar ratio of La element in the La ion-containing compound to Ni element in the Ni ion-containing compound is 1:(0.2 - 0.8); and / or, the mass ratio of the red mud to the La ion-containing compound is 1:(0.1 - 10), preferably 1:(0.1 - 5), more preferably 1:(0.1 - 1).

8. The preparation method according to any one of claims 4 to 7, characterized in that The steps of the heat treatment include: S1, perform a first heat treatment on the homogeneous mixture, filter and dry to obtain a solid; ​ ​ The second heat treatment is performed in a tube furnace; and / or The temperatures of the first heat treatment and the second heat treatment are each independently 700-1000° C.; and / or The time of the first heat treatment and the second heat treatment is independently 1-5 hours; Preferably, the heating rate of the second heat treatment is 1-5°C / min.

9. Use of the red mud-based catalyst according to any one of claims 1 to 3 or the red mud-based catalyst prepared according to any one of claims 4 to 8 in treating organic wastewater; Preferably, the organic matter is selected from antibiotics, preferably one or more of sulfonamide antibiotics, quinolone antibiotics or tetracycline antibiotics; more preferably one or more of sulfamethoxazole, levofloxacin, norfloxacin, ciprofloxacin or tetracycline hydrochloride.

10. A method for treating organic wastewater, comprising: mixing the red mud-based catalyst according to any one of claims 1 to 3 or the red mud-based catalyst obtained by the preparation method according to any one of claims 4 to 8, persulfate, and organic-containing wastewater to degrade organic matter in the organic-containing wastewater; Preferably, the organic matter is selected from antibiotics, preferably one or more selected from sulfonamide antibiotics, quinolone antibiotics or tetracycline antibiotics; more preferably one or more selected from sulfamethoxazole, levofloxacin, norfloxacin, ciprofloxacin or tetracycline hydrochloride; Preferably, the organic matter content in the organic wastewater is 10-50 mg / L; and / or, the persulfate is selected from peroxymonosulfate and / or peroxydisulfate; and / or, the amount of the red mud-based catalyst is 0.01-1 g / L, preferably 0.2-0.6 g / L, more preferably 0.4-0.6 g / L; and / or, the amount of the persulfate is 0.1-5 mM, preferably 2-4 mM; and / or, the degradation temperature is 15-30°C, And / or, the degradation time is 30-80 min; And / or, the pH of the organic-containing wastewater is 3-11.

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