Manganese slag and papermaking sludge composite catalyst, preparation method and pollutant degradation application

Abstract

The application discloses a manganese residue and papermaking sludge composite catalyst, a preparation method and pollutant degradation application, and belongs to the field of catalyst technology, and solves the important problems of low degradation efficiency and high cost of the catalyst for degrading organic pollutants in the prior art. The manganese residue and papermaking sludge composite catalyst is prepared by using manganese residue and papermaking sludge as raw materials and through high-temperature calcination. The preparation method comprises the following steps: uniformly mixing manganese residue and papermaking sludge, and then high-temperature calcining the mixture under a nitrogen atmosphere to obtain the manganese residue and papermaking sludge composite catalyst. The degradation method comprises the following steps: mixing the manganese residue and papermaking sludge composite catalyst, an aqueous solution containing organic pollutants and an oxidizing agent, and stirring the mixture, so that the organic pollutants in the aqueous solution containing organic pollutants are degraded. The manganese residue and papermaking sludge composite catalyst preparation method is simple, low in cost, and has good application potential in the field of catalyzing degradation of organic pollutants.

Description

Technical Field

[0001] This invention belongs to the field of heterogeneous catalyst technology, specifically relating to a composite catalyst of manganese slag and papermaking sludge, its preparation method, and its application in pollutant degradation. Background Technology

[0002] Manganese slag is a major product of electrolytic manganese ore processing. The harmless treatment and subsequent resource utilization of manganese slag, a solid waste generated during its production, has become an urgent problem to solve. Manganese slag has certain hazards; if not properly handled, it can harm the environment. Currently, the main method of manganese slag disposal is stockpiling, which occupies a large amount of land and pollutes groundwater, thus affecting human health. Recycling is not economically viable. Developing high-value functional materials is of great significance for the comprehensive utilization of manganese slag.

[0003] With the increasing demand for paper and the expansion of the industry, the treatment and utilization of papermaking sludge has always been a focus of researchers. Papermaking sludge mainly contains high-molecular-weight organic compounds such as cellulose, hemicellulose, and lignin, as well as fillers and coagulants, but does not contain heavy metals. It is both a biological solid waste and a biomass resource. How to recycle and utilize papermaking sludge with high added value has always been a research hotspot in this field.

[0004] Taking advantage of the characteristics of manganese slag and papermaking sludge, such as the presence of metallic elements and large specific surface area, high-value-added functional materials such as adsorbents and catalysts can be prepared. The use of manganese slag as a catalyst or catalyst carrier in the biomass pyrolysis for biomass energy production has also been extensively studied.

[0005] Industrial and municipal wastewater contains large amounts of organic pollutants. These pollutants, due to their reluctance to degrade and high toxicity, pose significant threats to the ecological environment and human health. The reaction of catalysts with oxidants to generate highly reactive free radicals can effectively degrade organic pollutant molecules. However, existing catalysts for organic pollutant degradation are costly, complex to prepare, and have low degradation efficiency. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a composite catalyst of manganese slag and papermaking sludge and its preparation method, which solves the problems of high cost, complex preparation and low degradation rate of existing catalysts used to degrade organic pollutants.

[0007] The objective of this invention is mainly achieved through the following technical solutions:

[0008] This invention provides a composite catalyst of manganese slag and papermaking sludge, which is prepared by reacting manganese slag and papermaking sludge. The manganese slag contains 20% to 25% iron oxide and 10% to 15% manganese oxide by mass, and the mass ratio of manganese slag to papermaking sludge is 0:1 to 1:0.

[0009] Furthermore, papermaking sludge is a type of biomass waste from the papermaking industry.

[0010] Furthermore, papermaking sludge mainly contains large amounts of carbon, plant fiber, lignin and its derivatives.

[0011] This invention also provides a method for preparing a composite catalyst of manganese slag and papermaking sludge, comprising the following steps:

[0012] Step 1: Dry, grind, and sieve the manganese slag and papermaking sludge separately, then mix and grind them evenly to obtain a mixture;

[0013] Step 2: React the mixture under an inert gas atmosphere to obtain the reactants;

[0014] Step 3: Cool the reactants to obtain a composite catalyst of manganese slag and papermaking sludge.

[0015] Furthermore, the inert gas is nitrogen, and the inert atmosphere is mainly to prevent reducing substances (such as carbon and low-valent manganese) from being oxidized.

[0016] Furthermore, in step 1 above, both the manganese slag and the papermaking sludge particles are passed through a 200-mesh sieve.

[0017] Further, in step 1 above, the uniform mixing of manganese slag and papermaking sludge includes the following steps: mixing manganese slag and papermaking sludge in different mass ratios of 0:1, 1:2, 1:1, 2:1, and 1:0. In order to obtain manganese slag and papermaking sludge with a mass ratio of 0:1 to 1:0, the two are dried at 90 to 120°C, passed through a 200-mesh sieve, and then thoroughly mixed according to the ratio.

[0018] Furthermore, the mass of papermaking sludge added each time gradually decreases.

[0019] Furthermore, after mixing the two, add 20-80% ethanol solution and sonicate for 30 minutes to mix thoroughly again, then dry at 90-120℃ until completely dry.

[0020] Furthermore, in step 2 above, the heating temperature is 300℃~800℃, the heating rate is 5~10℃ / min, and the holding time is 1~3h.

[0021] Furthermore, step 2 above includes the following steps:

[0022] Step 2-1: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen gas.

[0023] Step 2-2: Heat the temperature to 300℃~800℃ at a heating rate of 10℃ / min and keep it at that temperature for 1h. The papermaking sludge becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron substances, and the manganese oxide is also reduced to low-valent manganese substances, thereby obtaining the reaction products.

[0024] Furthermore, in step 3 above, the product in the tube furnace is cooled to room temperature.

[0025] This invention also provides an application for the degradation of pollutants, comprising the following steps:

[0026] Step a: Mix manganese slag with papermaking sludge composite catalyst, aqueous solution of organic pollutants and oxidant;

[0027] Step b: Stir the mixture obtained in step a to react, so that the organic pollutants in the aqueous solution are dissolved.

[0028] The pollutants are degraded.

[0029] Furthermore, the oxidizing agent mentioned above is persulfate.

[0030] Furthermore, persulfate is potassium persulfate.

[0031] Furthermore, the organic pollutant is a dye, and the concentration of the organic dye is 10–40 mg / L.

[0032] Furthermore, step a above includes the following steps: adding the composite catalyst and oxidant of manganese slag and papermaking sludge into the aqueous solution of organic pollutants.

[0033] Furthermore, the amount of the composite catalyst of manganese slag and papermaking sludge in each liter of the organic pollutant aqueous solution is 0.2–0.8 g. Furthermore, the amount of persulfate in each liter of the organic pollutant aqueous solution is 0.1 g.

[0034] ~1mmol.

[0035] Furthermore, in step b above, the stirring reaction time is 60 minutes.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] a) The manganese slag and papermaking sludge composite catalyst provided by this invention utilizes manganese slag and waste papermaking sludge from industrial waste as raw materials, and is prepared through co-reaction. Specifically, the active components iron and manganese in the manganese slag are ferric ions (Fe3+) and ferrous ions (Fe2+) before the high-temperature reaction, while ferric ions (Fe3+) and manganese ions (Mn2+) have low catalytic activity. During the high-temperature roasting reaction, biomass carbonization can reduce some of the ferric ions in iron oxide to lower valence states, and manganese oxide is also reduced to lower valence manganese substances, thereby improving the catalytic activity of the manganese slag.

[0038] b) The manganese slag and papermaking sludge composite catalyst provided by the present invention uses manganese slag and papermaking sludge from waste materials as raw materials. Therefore, the above-mentioned manganese slag and papermaking sludge composite catalyst has the characteristics of being green, low-cost, and environmentally friendly.

[0039] c) The preparation method of the composite catalyst of manganese slag and papermaking sludge provided by the present invention has a simple process, is easy to operate, and is easy to scale up.

[0040] d) The pollutant degradation method provided by the present invention utilizes the reaction of low-valent iron and low-valent manganese in the composite catalyst of manganese slag and papermaking sludge with oxidants to generate highly oxidizing hydroxyl radicals or sulfate radicals, as well as superoxide anions, singlet oxygen, etc., which can oxidize and degrade most organic pollutants in water.

[0041] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0042] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0043] Figure 1 This is a graph showing the degradation rate of methyl orange by a composite catalyst of manganese slag and papermaking sludge with different ratios in Example 8 of the present invention.

[0044] Figure 2 This is a graph showing the degradation rate of methyl orange by a composite catalyst of manganese slag and papermaking sludge at different calcination temperatures in Example 9 of the present invention.

[0045] Figure 3 This is a graph showing the degradation rate of methyl orange in the composite phase catalyst of different manganese slag and papermaking sludge in Example 10 of the present invention.

[0046] Figure 4 This is a graph showing the degradation rate of methyl orange by a composite catalyst of manganese slag and papermaking sludge with different persulfate concentrations in Example 11 of the present invention.

[0047] Figure 5 This is a graph showing the degradation rate of methyl orange by a composite catalyst of manganese slag and papermaking sludge with different methyl orange concentrations in Example 12 of the present invention.

[0048] Figure 6 The X-ray spectra of the catalysts prepared in Examples 1, 2, 3, 4, and 5 of this invention are shown.

[0049] Figure 7 The X-ray spectra of the catalysts prepared in Examples 3, 6, and 7 of this invention are shown.

[0050] Figure 8 The images show the SEM spectra of the catalysts prepared in Examples 1, 2, 3, 4, and 5 of this invention.

[0051] Figure 9 The images show the SEM spectra of the catalysts prepared in Examples 3, 6, and 7 of this invention. Detailed implementation method:

[0052] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with Embodiment 1 of the present invention, serve to illustrate the principles of the present invention.

[0053] This invention provides a composite catalyst of manganese slag and papermaking sludge, which is prepared by reacting manganese slag and papermaking sludge. The manganese slag contains 20% to 25% iron oxide and 10% to 15% manganese oxide by mass, and the mass ratio of manganese slag to papermaking sludge is 0:1 to 1:0.

[0054] Compared with existing technologies, the manganese slag and papermaking sludge composite catalyst provided by this invention utilizes industrial waste (manganese slag) and waste papermaking sludge as raw materials, and is prepared through a co-carbonization reaction. Specifically, the active components iron and manganese in the manganese slag are ferric ions (Fe3+) and ferrous ions (Fe2+) before the high-temperature reaction, while ferric ions (Fe3+) and manganese ions (Mn2+) have low catalytic activity. During the high-temperature roasting reaction, biomass carbonization can reduce some of the high-valence ions in iron oxide and manganese oxide to low-valence states, thereby improving the catalytic activity of the manganese slag and obtaining the manganese slag and papermaking sludge composite catalyst.

[0055] This invention also provides a method for preparing a composite catalyst of manganese slag and papermaking sludge, with the following steps:

[0056] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture;

[0057] Step 2: Heat the mixture and react it under an inert atmosphere (nitrogen) to obtain the reaction product;

[0058] Step 3: The reaction products are cooled sequentially to obtain a composite catalyst of manganese slag and papermaking sludge.

[0059] The reaction formulas involved in the above preparation method are as follows:

[0060] C + Fe₂O₃ → Fe₃O₄ + CO

[0061] CO + 3Fe₂O₃ → 2Fe₃O₄ + CO₂

[0062] C + Fe3O4 → 3Fe 0 +4CO

[0063] C + MnO → Mn 0 +CO

[0064] To improve the catalytic activity of the manganese slag and papermaking sludge composite catalyst, both the manganese slag and papermaking sludge were passed through a 200-mesh sieve in step 1 above. This is because the particle size of both manganese slag and papermaking sludge is too large, resulting in a small specific surface area. This leads to reduced contact between the manganese slag and papermaking sludge, resulting in incomplete reaction. Furthermore, using larger-particle manganese slag and papermaking sludge as raw materials results in a relatively small specific surface area and lower catalytic activity in the prepared manganese slag and papermaking sludge composite catalyst.

[0065] To achieve uniform mixing of manganese slag and papermaking, step 1 above includes the following steps: manganese slag and papermaking waste are mixed in different ratios of 0:1, 1:4, 1:2, 1:1, 2:1, 4:1, and 1:0. Then, 50% ethanol solution is added and ultrasonically mixed for 30 minutes. Finally, the mixture is dried at 105°C until completely dry.

[0066] In order to control the reaction rate of the carbonization reaction, in step 2 above, the heating temperature is 300-800℃ and the heating rate is 10℃ / min.

[0067] Specifically, step 2 above includes the following steps:

[0068] Step 21: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen gas.

[0069] Step 22: Heat to 300℃~800℃ at a heating rate of 10℃ / min and hold for 1~3h. The papermaking sludge becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valence iron, thereby obtaining the reaction product.

[0070] This invention also provides an application of a composite catalyst of manganese slag and papermaking sludge for pollutant degradation, comprising the following steps:

[0071] Step a: Mix manganese slag with a composite catalyst of papermaking sludge, an aqueous solution of organic pollutants, and an oxidant, wherein the oxidant is persulfate (potassium persulfate).

[0072] Step b: Stir the mixture obtained in step a to degrade the organic pollutants in the aqueous solution.

[0073] It should be noted that the above-mentioned pollutant degradation method utilizes the reaction of low-valent iron and low-valent manganese in the composite catalyst of manganese slag and papermaking sludge with oxidants to generate highly oxidizing hydroxyl radicals or sulfate radicals, as well as superoxide anions and singlet oxygen, thereby oxidizing and degrading organic pollutants in water. Free radicals have a certain effect on the degradation of organic pollutants, and highly oxidizing free radicals can basically degrade most organic pollutants.

[0074] For the combined addition of manganese slag and papermaking sludge catalyst, aqueous solution of organic pollutants and oxidant, specifically, step a above includes the following steps: adding manganese slag and papermaking sludge composite catalyst and oxidant to aqueous solution of organic pollutants and stirring for 60 min.

[0075] Specifically, the dosage of the manganese slag and papermaking sludge composite catalyst is 0.1–0.8 g per liter of organic pollutant aqueous solution. Example 1

[0076] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0077] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 0:1.

[0078] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is then increased to 800°C at a rate of 10°C / min and held for 1 hour, thus transforming the papermaking sludge into porous biochar.

[0079] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0080] Example 2

[0081] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0082] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 1:2.

[0083] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is increased to 800℃ at a rate of 10℃ / min and held for 1 hour. The papermaking sludge char becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products.

[0084] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0085] Example 3

[0086] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0087] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 1:1.

[0088] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is increased to 800℃ at a rate of 10℃ / min and held for 1 hour. The papermaking sludge char becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products.

[0089] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0090] Example 4

[0091] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0092] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 2:1.

[0093] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is increased to 800℃ at a rate of 10℃ / min and held for 1 hour. The papermaking sludge char becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products.

[0094] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0095] Example 5

[0096] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0097] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 1:0.

[0098] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tube furnace with nitrogen. The temperature is then increased to 800°C at a rate of 10°C / min and held for 1 hour to obtain the reaction product.

[0099] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0100] Example 6

[0101] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0102] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 1:1.

[0103] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is increased to 300°C at a rate of 10°C / min and held for 1 hour. The papermaking sludge char becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products.

[0104] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0105] Example 7

[0106] In this embodiment, the manganese slag and papermaking sludge composite catalyst uses manganese slag and papermaking sludge particles that have both passed through a 200-mesh sieve. The preparation method of this manganese slag and papermaking sludge composite catalyst is as follows:

[0107] Step 1: Mix the manganese slag and papermaking sludge evenly to obtain a mixture. The mass ratio of manganese slag to papermaking sludge is 1:1.

[0108] Step 2: Before high-temperature calcination, nitrogen gas is introduced for 40 minutes to fill the tubular furnace with nitrogen. The temperature is increased to 500℃ at a rate of 10℃ / min and held for 1 hour. The papermaking sludge char becomes porous biochar, and the iron oxide in the manganese slag is reduced to low-valent iron and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products.

[0109] Step 3: Cool the reaction product to room temperature to obtain a composite catalyst of manganese slag and papermaking sludge.

[0110] Example 8

[0111] The pollutant degradation method in this embodiment uses the manganese slag and papermaking sludge composite phase catalysts from Examples 1, 2, 3, 4, and 5. The pollutant degradation method includes the following steps:

[0112] Step a: Stir together manganese slag with papermaking sludge composite catalyst, oxidant (persulfate) and organic pollutant aqueous solution (containing 20 mg / L tetracycline hydrochloride). In each liter of organic pollutant aqueous solution, the amount of manganese slag and papermaking sludge composite catalyst is 0.6 g / L and the amount of persulfate is 1 mmol.

[0113] Step b: Stir the mixture obtained in step a for 60 minutes to degrade the organic pollutants in the aqueous solution.

[0114] Degradation reaction curve as shown Figure 1 As shown, the degradation rates of methyl orange dye (concentration of 20 mg / L) in Examples 1, 2, 3, 4, and 5 were 96.8%, 99.3%, 98.15%, 44.6%, and 27%, respectively.

[0115] Example 9

[0116] The pollutant degradation method in this embodiment uses the manganese slag and papermaking sludge composite phase catalyst from Examples 3, 6, and 7. The pollutant degradation method includes the following steps:

[0117] Step a: Stir together manganese slag with papermaking sludge composite catalyst, oxidant (persulfate) and organic pollutant aqueous solution (containing 20 mg / L tetracycline hydrochloride). In each liter of organic pollutant aqueous solution, the amount of manganese slag and papermaking sludge composite catalyst is 0.6 g and the amount of persulfate is 1 mmol.

[0118] Step b: Stir the mixture obtained in step a for 60 minutes to degrade the organic pollutants in the aqueous solution.

[0119] Degradation reaction curve as shown Figure 2 As shown, the degradation rates of methyl orange dye (concentration of 20 mg / L) in Examples 3, 6, and 7 were 98.15%, 32.75%, and 28.55%, respectively.

[0120] Example 10

[0121] The pollutant degradation method in this embodiment uses the manganese slag and papermaking sludge composite catalyst from Example 3. The dosage of the manganese slag and papermaking sludge composite catalyst is 0.2 g / L, 0.4 g / L, 0.6 g / L, and 0.8 g / L. The pollutant degradation method includes the following steps:

[0122] Step a: Stir together manganese slag with papermaking sludge composite phase catalyst, oxidant (persulfate) and organic pollutant aqueous solution. The amount of persulfate used in each liter of organic pollutant aqueous solution is 1 mmol.

[0123] Step b: Stir the mixture obtained in step a for 60 minutes to degrade the organic pollutants in the aqueous solution.

[0124] Degradation reaction curve as shown Figure 3 As shown, the degradation rates of methyl orange dye (concentration of 20 mg / L) in the composite catalyst of manganese slag and papermaking sludge at dosages of 0.2 g / L, 0.4 g / L, 0.6 g / L, and 0.8 g / L were 74.1%, 94.6%, 98.15%, and 98.4%, respectively.

[0125] Example 11

[0126] The pollutant degradation method in this embodiment uses the manganese slag and papermaking sludge composite catalyst from Example 3, with persulfate dosages of 0.1 mM, 0.3 mM, 0.5 mM, and 1.0 mM. The pollutant degradation method includes the following steps:

[0127] Step a: Stir together manganese slag with papermaking sludge composite catalyst, oxidant (persulfate) and organic pollutant aqueous solution. The amount of manganese slag and papermaking sludge composite catalyst in each liter of organic pollutant aqueous solution is 0.6g.

[0128] Step b: Stir the mixture obtained in step a for 60 minutes to degrade the organic pollutants in the aqueous solution.

[0129] Degradation reaction curve as shown Figure 4 As shown, the degradation rates of methyl orange dye (concentration of 20 mg / L) with persulfate dosages of 0.1 mM, 0.3 mM, 0.5 mM, and 1.0 mM were 30.55%, 63.4%, 88.6%, and 98.15%, respectively.

[0130] Example 12

[0131] The pollutant degradation method in this embodiment uses the manganese slag and papermaking sludge composite catalyst from Example 3, with methyl orange dye concentrations of 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L. The pollutant degradation method includes the following steps:

[0132] Step a: Stir together manganese slag with papermaking sludge composite catalyst, oxidant (persulfate) and organic pollutant aqueous solution. The amount of manganese slag and papermaking sludge composite catalyst in each liter of organic pollutant aqueous solution is 0.6 g and the amount of persulfate is 0.1 mM.

[0133] Step b: Stir the mixture obtained in step a for 60 minutes to degrade the organic pollutants in the aqueous solution.

[0134] Degradation reaction curve as shown Figure 5 As shown, the degradation rates of methyl orange dye at concentrations of 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L are 98.16%, 98.15%, 93.3%, and 87.78%, respectively.

[0135] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite catalyst of manganese slag and papermaking sludge, characterized in that, The composite catalyst is prepared by reacting manganese slag and papermaking sludge. The manganese slag contains 20% to 25% iron oxide and 10% to 15% manganese oxide. The mass ratio of manganese slag to papermaking sludge is 0:1 to 1:1, and the manganese slag content is not 0. The preparation method of the composite catalyst includes the following steps: Step 1: Dry, grind, and sieve the manganese slag and papermaking sludge separately, and then mix them evenly to obtain the desired mixture; The manganese slag contains 20% to 25% iron oxide and 10% to 15% manganese oxide by mass. The papermaking sludge is waste biomass from the end of the papermaking process, containing a large amount of carbon, fine fibers, lignin and its derivatives, and some organic matter. Step 2: Before high-temperature calcination, nitrogen gas is introduced for a certain period of time to fill the tube furnace with nitrogen gas. Then, the temperature is increased to 300℃~800℃ at a heating rate of 5~10℃ / min and held for 1~3 hours. The papermaking sludge becomes porous biochar, the iron oxide in the manganese slag is reduced to low-valent iron, and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products. Step 3: After high-temperature calcination, the reaction product is cooled to obtain a composite catalyst of manganese slag and papermaking sludge.

2. A method for preparing a composite catalyst of manganese slag and papermaking sludge, characterized in that, Includes the following steps: Step 1: Dry, grind, and sieve the manganese slag and papermaking sludge separately, and then mix them evenly to obtain the desired mixture; The manganese slag contains 20% to 25% iron oxide and 10% to 15% manganese oxide. The mass ratio of the manganese slag to papermaking sludge is 0:1 to 1:1, and the manganese slag content is not 0. The papermaking sludge is waste biomass from the end of the papermaking process, containing a large amount of carbon, fine fibers, lignin and its derivatives, and some organic matter. To obtain manganese slag and papermaking sludge with a mass ratio of 0:1 to 1:1, the two were dried at 90 to 120°C and then passed through a 200-mesh sieve. After passing through the sieve, the two were thoroughly mixed at a mass ratio of 0:1 to 1:

1. Step 2: Before high-temperature calcination, nitrogen gas is introduced for a certain period of time to fill the tube furnace with nitrogen gas. Then, the temperature is increased to 300℃~800℃ at a heating rate of 5~10℃ / min and held for 1~3 hours. The papermaking sludge becomes porous biochar, the iron oxide in the manganese slag is reduced to low-valent iron, and the manganese oxide is reduced to low-valent manganese, thus obtaining the reaction products. Step 3: After high-temperature calcination, the reaction product is cooled to obtain a composite catalyst of manganese slag and papermaking sludge.

3. The method for preparing a composite catalyst of manganese slag and papermaking sludge according to claim 2, characterized in that, In step 1, manganese slag and papermaking sludge are mixed and ground evenly at a mass ratio of 0:1 to 1:

1. Then, 20-80% ethanol solution is added and ultrasonically mixed for a period of time. Finally, the mixture is dried at 90-120°C until completely dry.

4. An application of a composite catalyst of manganese slag and papermaking sludge for pollutant degradation, characterized in that, The composite catalyst according to claim 1 is used in the following steps: Step a: Mix manganese slag with papermaking sludge composite catalyst, aqueous solution of organic pollutants and oxidant; Step b: Continue stirring the mixture obtained in step a for a certain period of time to allow the organic pollutants in the solution to be degraded.

5. The application of the composite catalyst of manganese slag and papermaking sludge according to claim 4 for pollutant degradation, characterized in that, The amount of manganese slag and papermaking sludge composite catalyst used in each liter of organic pollutant aqueous solution is 0.2~0.8g.

6. The application of the composite catalyst of manganese slag and papermaking sludge according to claim 4 for pollutant degradation, characterized in that, The oxidant is persulfate.

7. The application of the composite catalyst of manganese slag and papermaking sludge according to claim 4 for pollutant degradation, characterized in that, The amount of the oxidant persulfate in each liter of aqueous solution of organic pollutants is 0.1 to 1 mmol.

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