Preparation method of manganese slag-based catalyst and application thereof

Abstract

The application discloses a preparation method of a manganese residue-based catalyst and application thereof, and belongs to the technical field of solid waste treatment. The application comprises the following steps: manganese residue is added into water and uniformly mixed to obtain a manganese residue turbid liquid; a soluble manganese salt solution and a potassium permanganate solution are mixed, and then added into the manganese residue turbid liquid to perform a hydrothermal reaction; and after washing and drying, a manganese residue-based catalyst is obtained. The catalyst prepared by using the manganese residue as a main raw material can efficiently degrade common organic wastewater, and the purpose of "waste treatment by waste" is achieved. In addition, the raw material manganese residue and the modifier are cheap and easy to obtain, the preparation method is simple, the production cost is low, and the application is beneficial to industrial popularization and use.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid waste treatment, and particularly relates to a preparation method of a manganese residue-based catalyst and application thereof. BACKGROUND

[0002] Manganese residue is an industrial solid waste obtained after manganese carbonate ore or manganese oxide ore is subjected to sulfuric acid leaching and solid-liquid separation in the production process of electrolytic manganese, electrolytic manganese dioxide or manganese sulfate. With continuous mining of ores, the grade of manganese ore in China is continuously reduced, and factors such as filter pressing process limit the rapid increase in the production of manganese residue. About 10 tons of waste residue are generated for each ton of product. The main chemical components of manganese residue are Si, Al, Ca, Fe, S and other elements, and it also contains soluble Mn 2+ ions and other harmful ions. Therefore, if manganese residue is not treated and randomly stacked, it will cause serious pollution to the surrounding air, water and soil. At present, manganese residue is mainly stacked in a residue bank, and comprehensive utilization is urgently needed. If comprehensive utilization of manganese-containing solid waste can be achieved, it can be used to treat organic industrial wastewater, which can achieve "waste treatment with waste". On the one hand, it can alleviate the pressure of storage and avoid environmental pollution, and on the other hand, it can generate direct economic benefits.

[0003] At present, many researches have reported the preparation of manganese residue-based catalysts and their application in the treatment of organic wastewater. However, there are still some problems:

[0004] For example, Chinese Patent Application No. 202010178574.3 discloses a preparation method of modified electrolytic manganese residue and its application in efficient degradation of X-3B. The modified electrolytic manganese residue is obtained by reacting electrolytic manganese residue with NaOH solution and EDTA-2Na. The modified electrolytic manganese residue and hydrogen peroxide are added to X-3B-containing wastewater, and the pH value of the system is adjusted to 1-5. The purpose of degrading X-3B is achieved by standing. The method is simple to operate, but the pH range of the reaction is narrow.

[0005] For example, Chinese Patent Application No. 202110153864.7 discloses a kind of oxygen-rich vacancy cobalt trioxide / manganese residue composite ternary metal magnetic catalyst and its preparation method and application. The oxygen-rich vacancy cobalt trioxide is first prepared, and then the ball-milled activated manganese residue is reacted with the oxygen-rich vacancy cobalt trioxide in water medium to obtain the composite ternary metal magnetic catalyst. The preparation method is simple to operate and has high degradation efficiency, but the composite material of the composite ternary metal magnetic catalyst uses divalent cobalt salt as one of the raw materials, which has high preparation cost.

[0006] As disclosed in Chinese Patent Application No. 202010143303.4, a solid waste-based catalyst and its preparation method and application are disclosed. The solid waste-based catalyst is prepared by mixing manganese slag and straw and ball milling. The preparation process is simple, and the catalyst can efficiently remove flotation reagents in mineral processing wastewater. However, the catalyst prepared by this method is only suitable for treating common collectors and frothers in mineral processing wastewater, such as ethyl xanthate, butyl black medicine, ethyl sulfonamide, ester-200, and terpineol, etc.

[0007] As disclosed in Chinese Patent Application No. 201910484385.6, a method for treating organic wastewater by using electrolytic manganese slag as a photocatalyst is disclosed. The electrolytic manganese slag is ground, washed, and dried, and then used as a photocatalyst. The photocatalyst is placed in organic wastewater and irradiated with ultraviolet light to degrade pollutants in the organic wastewater. Although the preparation method of the catalyst is simple, the catalyst only has a high degradation rate for carbamazepine, and the types of degraded organic pollutants are single. Moreover, the technology needs to rely on ultraviolet radiation for auxiliary degradation, which is not only costly but also difficult to realize industrial application. SUMMARY

[0008] In view of the above problems in the prior art, the present application provides a preparation method of a manganese slag-based catalyst and its application. The catalyst prepared by using manganese slag as the main raw material can efficiently degrade organic wastewater, and the operation method is simple, low in cost, and conducive to industrialization.

[0009] To achieve the above-mentioned purposes, the technical solutions of the present application are as follows:

[0010] A preparation method of a manganese slag-based catalyst, comprising the following steps: adding manganese slag into water and mixing to obtain a manganese slag slurry, then mixing a soluble manganese salt solution and a potassium permanganate solution, and adding them into the manganese slag slurry for hydrothermal reaction, and washing and drying to obtain the manganese slag-based catalyst.

[0011] Further, the preparation method of the manganese slag-based catalyst specifically comprises the following steps:

[0012] (1) Manganese slag treatment: drying the manganese slag at 105°C for 24h, sieving the dried manganese slag through a 100-mesh sieve to obtain pretreated manganese slag; adding 1g of the pretreated manganese slag into 5-15mL of water and oscillating for 12-48h to obtain a manganese slag slurry;

[0013] (2) Preparation of a modifier: adding 0.1-1.0g of a soluble manganese salt into 10-30mL of water and stirring uniformly to obtain a soluble manganese salt solution, i.e. modifier I; adding 0.1-0.6g of potassium permanganate into 10-30mL of water and stirring uniformly to obtain a potassium permanganate solution, i.e. modifier II; adding the modifier II into the modifier I under stirring, and continuing to stir for 10-15min after the addition is completed to obtain a mixed solution A;

[0014] (3) hydrothermal reaction: the manganese slag slurry is added into the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B is subjected to hydrothermal reaction at 100-180 DEG C for 0.5-24h, and after the reaction is completed, filtration is performed, the filter cake is washed with anhydrous ethanol and deionized water alternately until the washing liquid is neutral, and the washed filter cake is dried to prepare the manganese slag-based catalyst.

[0015] Further, in step (2), the soluble manganese salt is one or a combination of manganese chloride, manganese nitrate and manganese sulfate.

[0016] Further, the manganese slag contains 8-15wt% of manganese, more than 13wt% of iron, less than 1wt% of calcium and less than 7.5wt% of sulfur.

[0017] The application further provides the manganese slag-based catalyst prepared by the preparation method.

[0018] The application further provides an application of the manganese slag-based catalyst, and the manganese slag-based catalyst is applied to degradation of organic wastewater, and the organic wastewater is wastewater containing organic dyes and / or antibiotics.

[0019] Further, the application of the manganese slag-based catalyst specifically comprises the following steps: the manganese slag-based catalyst and potassium hydrogen persulfate are added into the organic wastewater and stirred to perform a degradation reaction.

[0020] Further, the pH value of the organic wastewater ranges from 2 to 12; the addition concentration of the manganese slag-based catalyst in the organic wastewater ranges from 0.5 to 2.0g / L; the addition concentration of the potassium hydrogen persulfate in the organic wastewater ranges from 0.1 to 1mmol / L; the concentration of the organic dyes in the organic wastewater is not higher than 100mg / L and / or the concentration of the antibiotics is not higher than 20mg / L; and in the degradation reaction process, the temperature of the degradation reaction ranges from 5 to 40 DEG C, and the time of the degradation reaction ranges from 5 to 30min.

[0021] The application has the following beneficial effects:

[0022] 1. The manganese slag is used as the main raw material in the application, and the prepared catalyst can efficiently degrade common organic wastewater, thereby achieving the purpose of "waste treatment with waste".

[0023] 2、The manganese slag-based catalyst of the present application has a wide pH range for degradation reaction: 2-12, a wide temperature range for degradation reaction: 5-40℃, a short time for degradation reaction: 5-30min, and can be used to treat various types of organic wastewater, such as organic dye wastewater (including common dye wastewater such as rhodamine, methylene blue, crystal violet, etc.), antibiotic wastewater, etc. In summary, the manganese slag-based catalyst of the present application has less restrictions on the conditions of organic matter degradation reaction, can realize efficient degradation of organic wastewater in a short time, and has a wide application field.

[0024] 3、The manganese slag-based catalyst of the present application can effectively degrade organic wastewater, and the removal rate of rhodamine B in the organic wastewater is more than 98% and the removal rate of tetracycline hydrochloride is more than 70% within 30min; after five cycles of use, the degradation effect of the manganese slag-based catalyst can basically remain at the original level. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The scanning electron microscope images of the pretreated manganese slag and the manganese slag-based catalyst in Example 1 of the present application, wherein a is the pretreated manganese slag and b is the manganese slag-based catalyst;

[0026] Figure 2 The change curve of the removal rate of rhodamine B by the manganese slag-based catalyst of Examples 1-7 and Comparative Examples 1-3;

[0027] Figure 3 The change curve of the removal rate of methylene blue by the manganese slag-based catalyst of Example 1 and Comparative Example 2;

[0028] Figure 4 The change curve of the removal rate of crystal violet by the manganese slag-based catalyst of Example 1 and Comparative Example 2;

[0029] Figure 5 The change curve of the removal rate of tetracycline hydrochloride by the manganese slag-based catalyst of Example 1 and Comparative Example 2;

[0030] Figure 6 The change curve of the removal rate of rhodamine B by the manganese slag-based catalyst of Example 1 at different pH values;

[0031] Figure 7 The change curve of the removal rate of rhodamine B by the manganese slag-based catalyst of Example 1 after five cycles. DETAILED DESCRIPTION

[0032] The present application will be further described below in combination with the drawings and specific examples.

[0033] Example 1

[0034] A preparation method of a manganese residue-based catalyst, comprising the following steps:

[0035] (1) manganese residue treatment: the manganese residue is baked at 105 DEG C for 24h, and then sieved through a 100-mesh sieve to obtain pretreated manganese residue; 1g of the pretreated manganese residue is added into 10mL of water and shaken for 24h to prepare a manganese residue turbid liquid; the manganese residue is from a Guangxi electrolytic manganese dioxide enterprise which produces electrolytic manganese dioxide by using manganese oxide ore as raw material, and the manganese element content in the manganese residue is 12.32wt%, the iron element content is 15.26wt%, the calcium element content is 0.33wt%, and the sulfur element content is 6.92wt%;

[0036] (2) modifier preparation: 0.3380g of manganese sulfate (MnSO4·4H2O) is added into 20mL of water and stirred for 15min to obtain a soluble manganese salt solution, i.e. modifier I; 0.2448g of potassium permanganate is added into 20mL of water and stirred for 15min to obtain a potassium permanganate solution, i.e. modifier II; the modifier II is added into the modifier I under stirring, and after the addition is completed, the stirring is continued for 15min to prepare a mixed liquid A;

[0037] (3) hydrothermal reaction: the manganese residue turbid liquid is added into the mixed liquid A and stirred uniformly to prepare a mixed liquid B; the mixed liquid B is subjected to hydrothermal reaction at 160 DEG C for 6h in a reaction kettle, and after the reaction is completed, the filter cake is washed with anhydrous ethanol and deionized water alternately until the washing liquid is neutral, and then the washed filter cake is dried to obtain a manganese residue-based catalyst.

[0038] As shown in FIG. 1, Figure 1 a is the pretreated manganese residue obtained in step (1) of the embodiment, and b is the manganese residue-based catalyst obtained in the embodiment. Figure 1 It can be seen that, compared with the pretreated manganese residue, a large number of spherical particles appear in the modified manganese residue-based catalyst, the particle surface has a flower-like structure, the specific surface area of the catalyst is larger, more active sites are provided for the catalytic reaction, and the catalytic reaction activity of the catalyst is higher.

[0039] Example 2

[0040] A preparation method of a manganese residue-based catalyst, comprising the following steps:

[0041] (1) manganese residue treatment: the manganese residue is baked at 105 DEG C for 24h, and then sieved through a 100-mesh sieve to obtain pretreated manganese residue; 1g of the pretreated manganese residue is added into 10mL of water and shaken for 24h to prepare a manganese residue turbid liquid; the manganese residue is from a Guangxi electrolytic manganese dioxide enterprise which produces electrolytic manganese dioxide by using manganese oxide ore as raw material, and the manganese element content in the manganese residue is 12.32wt%, the iron element content is 15.26wt%, the calcium element content is 0.33wt%, and the sulfur element content is 6.92wt%;

[0042] (2) Modifier preparation: 0.3380 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water and stirred uniformly to obtain modifier I; 0.2448 g of potassium permanganate was added to 20 mL of water and stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, stirring was continued for 15 min to prepare a mixed solution A;

[0043] (3) Hydrothermal reaction: the manganese slag slurry was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 100℃ for 12 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; and the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0044] Example 3

[0045] A preparation method of a manganese slag-based catalyst, comprising the following steps:

[0046] (1) Manganese slag treatment: the manganese slag was baked at 105℃ for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and oscillated for 24 h to prepare a manganese slag slurry; the manganese slag was the same as in Example 1;

[0047] (2) Modifier preparation: 0.3380 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water and stirred uniformly to obtain modifier I; 0.2448 g of potassium permanganate was added to 20 mL of water and stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, stirring was continued for 15 min to prepare a mixed solution A;

[0048] (3) Hydrothermal reaction: the manganese slag slurry was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 100℃ for 12 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; and the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0049] Example 4

[0050] A preparation method of a manganese slag-based catalyst, comprising the following steps:

[0051] (1) Manganese slag treatment: the manganese slag was baked at 105℃ for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and oscillated for 24 h to prepare a manganese slag slurry; the manganese slag was the same as in Example 1;

[0052] (2) modifier preparation: 0.3380 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water, stirred uniformly to obtain modifier I; 0.2448 g of potassium permanganate was added to 20 mL of water, stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, the stirring was continued for 15 min to prepare a mixed solution A;

[0053] (3) hydrothermal reaction: the manganese slag slurry was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 160℃ for 0.5 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0054] Example 5

[0055] A preparation method of a manganese slag-based catalyst, comprising the following steps:

[0056] (1) manganese slag treatment: the manganese slag was baked at 105℃ for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and oscillated for 24 h to prepare a manganese slag slurry; the manganese slag was the same as in Example 1;

[0057] (2) modifier preparation: 0.3380 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water, stirred uniformly to obtain modifier I; 0.2448 g of potassium permanganate was added to 20 mL of water, stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, the stirring was continued for 15 min to prepare a mixed solution A;

[0058] (3) hydrothermal reaction: the manganese slag slurry was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 160℃ for 0.5 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0059] Example 6

[0060] A preparation method of a manganese slag-based catalyst, comprising the following steps:

[0061] (1) manganese slag treatment: the manganese slag was baked at 105℃ for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and oscillated for 24 h to prepare a manganese slag slurry; the manganese slag was the same as in Example 1;

[0062] (2) Modifier preparation: 0.1690 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water and stirred uniformly to obtain modifier I; 0.1224 g of potassium permanganate was added to 20 mL of water and stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, stirring was continued for 15 min to prepare a mixed solution A;

[0063] (3) Hydrothermal reaction: the manganese slag turbid liquid was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 160℃ for 6 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; and the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0064] Example 7

[0065] A preparation method of a manganese slag-based catalyst comprises the following steps:

[0066] (1) Manganese slag treatment: the manganese slag was baked at 105℃ for 24 h and sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and oscillated for 24 h to prepare a manganese slag turbid liquid; the manganese slag was the same as in Example 1.

[0067] (2) Modifier preparation: 0.8450 g of manganese sulfate (MnSO4.4H2O) was added to 20 mL of water and stirred uniformly to obtain modifier I; 0.612 g of potassium permanganate was added to 20 mL of water and stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, stirring was continued for 15 min to prepare a mixed solution A;

[0068] (3) Hydrothermal reaction: the manganese slag turbid liquid was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to hydrothermal reaction at 160℃ for 6 h in a reaction kettle, and after the reaction was completed, suction filtration was performed; the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral; and the washed filter cake was dried to prepare a manganese slag-based catalyst.

[0069] Comparative Example 1

[0070] A preparation method of a manganese slag-based catalyst comprises the following steps: the manganese slag was baked at 105℃ for 24 h and sieved through a 100-mesh sieve to obtain a manganese slag-based catalyst; and the manganese slag was the same as in Example 1.

[0071] Comparative Example 2

[0072] A preparation method of a manganese slag-based catalyst comprises the following steps:

[0073] (1) Manganese slag treatment: the manganese slag was baked at 105°C for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and shaken for 24 h to prepare a manganese slag slurry; the manganese slag was from a certain electrolytic manganese enterprise in Guangxi, which produced electrolytic manganese using manganese carbonate ore as raw material, and the manganese slag contained 7.15 wt% of manganese, 11.19 wt% of iron, 17.68 wt% of calcium, and 19.80 wt% of sulfur;

[0074] (2) Hydrothermal reaction: 40 mL of deionized water was added to the manganese slag slurry, and a hydrothermal reaction was performed at 160°C for 6 h in a reaction kettle; after the reaction was completed, suction filtration was performed, the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral, and the washed filter cake was dried to obtain manganese slag after direct hydrothermal reaction.

[0075] Comparative Example 3

[0076] A method for preparing a manganese slag-based catalyst, comprising the following steps:

[0077] (1) Manganese slag treatment: the manganese slag was baked at 105°C for 24 h, and then sieved through a 100-mesh sieve to obtain pretreated manganese slag; 1 g of the pretreated manganese slag was added to 10 mL of water and shaken for 24 h to prepare a manganese slag slurry; the manganese slag was from a certain electrolytic manganese enterprise in Guangxi, which produced electrolytic manganese using manganese carbonate ore as raw material, and the manganese slag contained 7.15 wt% of manganese, 11.19 wt% of iron, 17.68 wt% of calcium, and 19.80 wt% of sulfur;

[0078] (2) Preparation of modifier: 0.3380 g of manganese sulfate (MnSO4·4H2O) was added to 20 mL of water and stirred uniformly to obtain modifier I; 0.2448 g of potassium permanganate was added to 20 mL of water and stirred uniformly to obtain modifier II; the modifier II was added to the modifier I under stirring, and after the addition was completed, stirring was continued for 15 min to prepare a mixed solution A;

[0079] (3) Hydrothermal reaction: the manganese slag slurry was added to the mixed solution A and stirred uniformly to prepare a mixed solution B; the mixed solution B was subjected to a hydrothermal reaction at 160°C for 6 h in a reaction kettle; after the reaction was completed, suction filtration was performed, the filter cake was washed with anhydrous ethanol and deionized water alternately until the washing liquid was neutral, and the washed filter cake was dried to obtain a manganese slag-based catalyst.

[0080] Application Example 1

[0081] Treatment of organic dye wastewater containing rhodamine: the manganese slag-based catalyst prepared in Example 1-7 and the potassium hydrogen persulfate were added into the organic wastewater with stirring to carry out a degradation reaction, the pH value of the organic wastewater was 4.88; the addition concentration of the manganese slag-based catalyst in the organic wastewater was 1 g / L; the addition concentration of the potassium hydrogen persulfate in the organic wastewater was 0.5 mmol / L; the concentration of rhodamine B in the organic wastewater was 20 mg / L; during the degradation reaction, the temperature of the degradation reaction was 25 ℃, and the time of the degradation reaction was 30 min. The degradation effect was detected by using an ultraviolet-visible spectrophotometer, and the removal rate (η) was calculated according to the following formula:

[0082]

[0083] wherein Co and Ct are the initial concentration and the concentration of rhodamine B in the wastewater at t time, mg / L, respectively, and t is the degradation time, min. t

[0084] The removal rate (%) of rhodamine B by each group of manganese slag-based catalysts is shown in Table 1 and Figure 2

[0085] Table 1

[0086]

[0087] As shown in Table 1 and Figure 2 It can be seen from Table 1 and Table 2 that the manganese slag-based catalyst prepared in Examples 1-7 has a very good degradation effect on rhodamine B, and the removal rate is more than 98.98% within 30 min; in Comparative Example 1, the manganese slag is directly used as a catalyst, and the removal rate of rhodamine B is greatly reduced, only 53.05%; in Comparative Example 2, the manganese slag is not modified but directly subjected to a hydrothermal reaction, and the removal rate is greatly reduced, only 27.63%; in Comparative Example 3, manganese slag with different element contents is used, and the removal rate is obviously reduced.

[0088] Application Example 2

[0089] Treatment of organic dye wastewater containing methylene blue: the manganese slag-based catalyst prepared in Example 1 and the potassium hydrogen persulfate were added into the organic wastewater with stirring to carry out a degradation reaction, the pH value of the organic wastewater was 8.6; the addition concentration of the manganese slag-based catalyst in the organic wastewater was 1 g / L; the addition concentration of the potassium hydrogen persulfate in the organic wastewater was 0.5 mmol / L; the concentration of methylene blue in the organic wastewater was 20 mg / L; during the degradation reaction, the temperature of the degradation reaction was 25 ℃, and the time of the stirring degradation reaction was 30 min. The degradation effect was detected by using an ultraviolet-visible spectrophotometer, and the removal rate (η) was calculated according to the following formula:

[0090] ​​

[0091] Where C0 and C t are the initial concentration of methylene blue in the wastewater and the concentration at time t of degradation reaction, mg / L, and t is the degradation time, min.

[0092] The removal rates (%) of methylene blue by each group of manganese slag-based catalysts are shown in Table 2 and Figure 3 As shown:

[0093] Table 2

[0094]

[0095] As shown in Table 2 and Figure 3 As shown, the manganese slag-based catalyst prepared in Example 1 has a good degradation effect on methylene blue, with a removal rate of 99.55% within 30 minutes, while the removal rate of Comparative Example 2 is only 37.50% within 30 minutes.

[0096] Application Example 3

[0097] Treatment of organic dye wastewater containing crystal violet: The manganese slag-based catalyst and potassium persulfate prepared in Example 1 and Comparative Example 2 were added to the organic wastewater and stirred to carry out a degradation reaction. The pH value of the organic wastewater was 5.75; the manganese slag-based catalyst was added to the organic wastewater at a concentration of 1 g / L; the potassium persulfate was added to the organic wastewater at a concentration of 0.5 mmol / L; and the crystal violet concentration in the organic wastewater was 20 mg / L. During the degradation reaction, the degradation temperature was 25°C and the stirring time was 30 minutes. The degradation effect was detected using a UV-visible spectrophotometer, and the removal rate (η) was calculated as follows:

[0098]

[0099] Where C0 and C t are the initial concentration of crystal violet in the wastewater and the concentration at time t of degradation reaction, mg / L, and t is the degradation time, min.

[0100] The removal rate (%) of each group of manganese slag-based catalysts on crystal violet is shown in Table 3 and Figure 4 As shown:

[0101] Table 3

[0102]

[0103] As shown in Table 3 and Figure 4 As shown, the manganese slag-based catalyst prepared in Example 1 has a good degradation effect on crystal violet, with a removal rate of 99.16% within 15 minutes, while the removal rate of Comparative Example 2 is only 92.60% within 30 minutes.

[0104] Application Example 4

[0105] Treatment of antibiotic wastewater containing tetracycline hydrochloride: The manganese slag-based catalyst and potassium persulfate prepared in Example 1 and Comparative Example 2 were added to organic wastewater and stirred to carry out a degradation reaction. The pH value of the organic wastewater was 4.98; the manganese slag-based catalyst was added to the organic wastewater at a concentration of 1 g / L; the potassium persulfate was added to the organic wastewater at a concentration of 0.5 mmol / L; the concentration of tetracycline hydrochloride in the organic wastewater was 20 mg / L; during the degradation reaction, the degradation reaction temperature was 25°C and the stirring time was 30 minutes. The degradation effect was detected using a UV-visible spectrophotometer, and the removal rate (η) was calculated as follows:

[0106]

[0107] Where C0 and C t are the initial concentration of tetracycline hydrochloride in the wastewater and the concentration at time t of degradation reaction, mg / L, and t is the degradation time, min.

[0108] The removal rate (%) of tetracycline hydrochloride by each group of manganese slag-based catalysts is shown in Table 4 and Figure 5 As shown:

[0109] Table 4

[0110]

[0111] As shown in Table 4 and Figure 5 As shown, the manganese slag-based catalyst prepared in Example 1 has a good degradation effect on tetracycline hydrochloride, with a removal rate of 70.92% within 30 minutes, while the removal rate of Comparative Example 2 is only 44.37% within 30 minutes.

[0112] Application Example 5

[0113] In order to verify that the manganese slag-based catalyst prepared by the present invention is applicable to a wide pH range, the present invention is directed to degradation of organic wastewater containing rhodamine B at different pH values, and the steps are as follows: the manganese slag-based catalyst and potassium persulfate prepared in Example 1 are added to the organic wastewater and stirred to carry out degradation reaction, and the pH values ​​of the organic wastewater are adjusted to 3, 4.88, 7, 9, and 11, respectively; the added concentration of the manganese slag-based catalyst in the organic wastewater is 1 g / L; the added concentration of potassium persulfate in the organic wastewater is 0.5 mmol / L; the concentration of rhodamine B in the organic wastewater is 20 mg / L; during the degradation reaction, the degradation reaction temperature is 25°C, and the degradation reaction time is 30 min. The removal rate (%) of rhodamine B in each pH group is shown in Table 5 and Table 6. Figure 6 As shown:

[0114] Table 5

[0115]

[0116] As shown in Table 5 and Figure 6 It can be seen that the manganese slag-based catalyst prepared in the embodiment 1 is applied to the treatment of organic wastewater with pH of 3-11, and the removal rate reaches more than 99% within 15 min, which indicates that the manganese slag-based catalyst prepared in the application has a wide pH application range.

[0117] Application Example 6

[0118] Manganese slag-based catalyst recycling experiment: the manganese slag-based catalyst after the degradation reaction in the embodiment 1 is separated from the liquid, and the separated manganese slag-based catalyst and potassium persulfate are added into the organic wastewater to perform a recycling degradation reaction, the pH value of the organic wastewater is 4.88, the addition concentration of the manganese slag-based catalyst in the organic wastewater is 1 g / L, the addition concentration of the potassium persulfate in the organic wastewater is 0.5 mmol / L, the concentration of rhodamine B in the organic wastewater is 20 mg / L, and the temperature of the degradation reaction is 25℃, and the time of the degradation reaction is 30 min. This step is repeated four times under the same conditions, and the recycling performance of the manganese slag-based catalyst is as shown in Table 6 and Figure 7 As shown in Table 6 and

[0119] Table 6

[0120]

[0121] Although the application has been disclosed with the preferred embodiments as above, it is not intended to limit the application, and any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the application, therefore, the protection scope of the application should be defined by the claims.

Claims

1. A process for the preparation of a manganese-slag based catalyst, characterized in that, The method comprises the following steps: adding manganese slag into water to obtain a manganese slag slurry, mixing a soluble manganese salt solution and a potassium permanganate solution, and then adding the mixture into the manganese slag slurry to perform a hydrothermal reaction, and the manganese slag-based catalyst is obtained after washing and drying. The method comprises the following steps: (1) manganese slag treatment: drying manganese slag to obtain pretreated manganese slag; adding 1 g of the pretreated manganese slag into 5-15 mL of water and oscillating for 12-48 h to obtain a manganese slag slurry; the manganese slag contains 8-15 wt% of manganese, more than 13 wt% of iron, less than 1 wt% of calcium, and less than 7.5 wt% of sulfur; (2) modifier preparation: adding 0.1-1.0 g of a soluble manganese salt into 10-30 mL of water and stirring to obtain a soluble manganese salt solution, namely, a modifier I; adding 0.1-0.6 g of potassium permanganate into 10-30 mL of water and stirring to obtain a potassium permanganate solution, namely, a modifier II; adding the modifier II into the modifier I under stirring, and continuously stirring for 10-15 min after the addition to obtain a mixed solution A; (3) hydrothermal reaction: adding the manganese slag slurry into the mixed solution A and stirring to obtain a mixed solution B; performing a hydrothermal reaction on the mixed solution B at 100-180 ℃ for 0.5-24 h, performing suction filtration after the reaction, washing the filter cake with anhydrous ethanol and deionized water alternately until the washing liquid is neutral, and drying the filter cake after washing to obtain the manganese slag-based catalyst. In step (2), the soluble manganese salt is one of manganese chloride, manganese nitrate, and manganese sulfate or a combination of two or more thereof. The manganese slag-based catalyst is prepared by the method of any one of claims 1-2.

2. A process for the preparation of a manganese slag based catalyst as claimed in claim 1, wherein: The manganese slag-based catalyst is applied to degrade organic wastewater containing organic dyes and / or antibiotics.

3. A manganese-slag based catalyst characterized by: The manganese slag-based catalyst and potassium peroxymonosulfate are added into the organic wastewater and stirred to perform a degradation reaction.

4. Use of a manganese slag-based catalyst according to claim 3, characterized in that: The pH value of the organic wastewater is 2-12; the addition concentration of the manganese slag-based catalyst in the organic wastewater is 0.5-2.0 g / L; the addition concentration of the potassium peroxymonosulfate in the organic wastewater is 0.1-1 mmol / L; the concentration of the organic dyes in the organic wastewater is not higher than 100 mg / L and / or the concentration of the antibiotics is not higher than 20 mg / L; and the temperature of the degradation reaction is 5-40 ℃ and the time of the degradation reaction is 5-30 min.

5. Use of a manganese slag-based catalyst according to claim 4, characterized in that: ​ 6. Use of a manganese slag-based catalyst according to claim 5, characterized in that: ​

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