Manganese catalyst material, preparation method thereof and treatment method of hydrometallurgy wastewater

Abstract

The invention relates to the technical field of water treatment, in particular to a manganese catalyst material, a preparation method thereof and a hydrometallurgy wastewater treatment method. The preparation method of the manganese catalyst material comprises the following steps: mixing manganese dioxide slag, a first auxiliary agent and water to obtain a first mixture; heating the first mixture, filtering, collecting filter residues, and drying to obtain a pre-modified material; mixing the pre-modified material with a second auxiliary agent to obtain a second mixture; carrying out ball milling treatment on the second mixture to prepare a manganese catalyst material; the first auxiliary agent comprises at least one of a nonionic surfactant and a cationic surfactant; the second auxiliary agent comprises a polyphosphate compound. The manganese catalyst material has the advantages of simple preparation method, high activity, low cost and good TOC removal effect.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and in particular to manganese catalyst materials and their preparation methods, as well as methods for treating hydrometallurgical wastewater. Background Technology

[0002] Hydrometallurgy is an important process for extracting valuable metals, but the wastewater it produces is complex, containing high concentrations of heavy metal ions (such as nickel, cobalt, and copper) and various salt ions (such as sulfate and chloride ions). Furthermore, the extraction process introduces a large amount of structurally stable and difficult-to-degrade organic matter. This type of wastewater causes significant environmental pollution and requires appropriate treatment before discharge. Technologies for treating heavy metals and salt ions, such as chemical precipitation, ion exchange, and membrane separation, are relatively mature and can effectively recover valuable metals and reduce salinity. However, the treatment of organic matter remains a technical challenge and a hot research topic in the industry.

[0003] For organic matter in hydrometallurgical wastewater, the main methods currently used for removal are adsorption and oxidation. Adsorption removes organic matter by adsorbing it with adsorbents (such as activated carbon and resin), which is relatively simple to operate and has a good removal effect. However, activated carbon is expensive, and the regeneration of resin requires additional regeneration reagents, resulting in high costs. Furthermore, the complexes formed after adsorption may cause secondary pollution. Oxidation degrades organic matter into small molecules, water, and carbon dioxide under the action of oxidants. Compared with adsorption, it is less expensive and more environmentally friendly, but it requires more stringent reaction conditions.

[0004] The extractants and diluents used in the extraction process of hydrometallurgy typically possess excellent stability, thus maintaining their performance during harsh metallurgical processes. While traditional oxidants have some oxidizing effect on these organic compounds, they cannot achieve deep removal. To meet emission standards, further adsorption and removal of organic compounds is usually required using adsorption methods. For example, CN111635051A discloses a wastewater treatment method in nickel-cobalt hydrometallurgy, including nickel-cobalt precipitation, magnesium precipitation, pressurized dissolved air flotation, adsorption, advanced oxidation, and MVR distillation. The combined use of adsorption and advanced oxidation methods has a good removal effect on organic compounds, but the cost is high. CN117228868A discloses a method for the combined removal of COD, oil, and heavy metals from cobalt-nickel raffinate, including steps such as oil removal adsorption, oil removal resin recovery, alkali precipitation, heavy metal removal adsorption, and heavy metal removal resin recovery. Although the resin, as an adsorbent, can be regenerated and recycled, it requires the use of expensive hydrogen peroxide for regeneration. Moreover, the COD in the wastewater treated by this method remains high, failing to achieve deep removal.

[0005] Therefore, it is necessary to develop a wastewater treatment method that is low in cost and has a good organic matter removal effect. Summary of the Invention

[0006] Based on this, one or more embodiments of this application provide a manganese catalyst material, a method for preparing the same, and a method for treating wastewater. The manganese catalyst material can remove TOC from wastewater at a high level using air as an oxidant, with mild reaction conditions and a simple and low-cost preparation method.

[0007] The technical solution of this application includes the following:

[0008] One or more embodiments of this application provide a method for preparing a manganese catalyst material, comprising the following steps:

[0009] Manganese dioxide slag, the first additive, and water are mixed to obtain the first mixture;

[0010] The first mixture is heated, filtered to collect the filter residue, and dried to obtain a pre-modified material.

[0011] The pre-modified material and the second additive are mixed to obtain a second mixture;

[0012] The second mixture was ball-milled to obtain the manganese catalyst material;

[0013] The first auxiliary agent includes at least one of a nonionic surfactant and a cationic surfactant;

[0014] The second adjuvant includes polyphosphate compounds.

[0015] The method for preparing the manganese catalyst material in this application utilizes a first additive to modify the surface of manganese dioxide slag, and then improves its surface properties and pore structure through heat treatment to form a pre-modified material. Subsequently, a second additive is introduced, followed by secondary modification and activation through ball milling. The mechanochemical effect of ball milling not only ensures that the second additive is uniformly coated on the material surface, but also further refines the particles, increases the specific surface area, and reduces surface defects. This dual modification strategy works synergistically to construct abundant active sites on the surface of the manganese catalyst material. These active sites can effectively activate oxygen in the air, generating highly oxidizing reactive oxygen species, thereby efficiently oxidizing and decomposing recalcitrant organic matter in wastewater under mild conditions.

[0016] In some embodiments, the manganese dioxide slag is a byproduct of nickel-cobalt hydrometallurgy; and / or,

[0017] The manganese dioxide slag contains ≥98% manganese dioxide by weight.

[0018] In this embodiment, inexpensive manganese dioxide waste residue is used as raw material to achieve "waste treatment", which reduces the preparation cost of the catalyst. At the same time, the process is simple and easy to scale up industrially.

[0019] In some embodiments, the weight ratio of the manganese dioxide slag, the first additive, and the water is 1:(0.001-0.01):(40-60); and / or,

[0020] The pre-modified material and the second additive are in a weight ratio of 100:(0.01-1).

[0021] In this embodiment, the manganese dioxide slag, the first additive, and water are in a suitable ratio range, which allows the first additive to more fully and uniformly modify the manganese dioxide slag, further optimizing the catalyst preparation efficiency and final performance.

[0022] In some embodiments, the step of heating the first mixture includes:

[0023] The first mixture is heated at a first temperature for a first time under a first pressure;

[0024] Wherein, the first pressure is 1.9 bar to 10 bar; the first temperature is 120°C to 180°C; and the first time is 2 hours to 20 hours.

[0025] In this embodiment, heating the first mixture at a suitable temperature for a suitable time can regulate the crystal structure transformation and surface hydroxylation degree of manganese dioxide slag, forming a pre-modified material with suitable pore structure and surface chemical properties, which is beneficial to obtaining higher catalytic activity.

[0026] In some embodiments, the step of ball milling the second mixture includes:

[0027] In the presence of ball milling media, the second mixture is ball milled at a first rotation speed for a second time;

[0028] The first rotational speed is 200 rpm to 1000 rpm; the second time is 30 min to 120 min.

[0029] In this embodiment, the second mixture is ball-milled at a suitable speed and for a suitable time, which enables the manganese dioxide to be fully activated, thus improving dispersibility and activity.

[0030] In some embodiments, the drying temperature is 100°C-180°C.

[0031] In some embodiments, the first adjuvant comprises at least one of cetyltrimethylammonium bromide and polysorbate; and / or,

[0032] The second adjuvant includes at least one of sodium hexametaphosphate and sodium tripolyphosphate.

[0033] One or more embodiments of this application also provide a manganese catalyst material prepared by the preparation method described above.

[0034] This manganese catalyst material has a loose and porous structure, high specific surface area and abundant surface active sites, and can efficiently catalyze the degradation of organic matter in wastewater by air oxidation under mild conditions.

[0035] One or more embodiments of this application also provide a method for treating hydrometallurgical wastewater, comprising the following steps:

[0036] After adding the manganese catalyst material mentioned above to the hydrometallurgical wastewater and mixing it, the mixture is stirred at a second temperature for a third time under air circulation conditions.

[0037] The second temperature is 40℃-90℃, and the third time is 0.5h-5h.

[0038] This treatment method uses inexpensive air as an oxidant and can achieve deep removal of TOC from hydrometallurgical wastewater under mild conditions close to ambient temperature and pressure. It does not require the addition of expensive chemical oxidants or combined adsorption processes, is easy to operate, and significantly reduces treatment costs.

[0039] Furthermore, the hydrometallurgical wastewater is the wastewater from nickel-cobalt hydrometallurgical wastewater after valuable metal recovery; and / or,

[0040] The TOC content in the hydrometallurgical wastewater is 200ppm-1000ppm; and / or,

[0041] The manganese catalyst material accounts for 0.5%-2% of the weight of the wastewater.

[0042] In this embodiment, optimizing the catalyst dosage for hydrometallurgical wastewater of specific sources and concentrations can maximize economic benefits while ensuring treatment effectiveness.

[0043] This application provides a method for preparing a manganese catalyst material. Through simple preparation steps, a highly active manganese catalyst material can be obtained, which catalyzes the oxidation and degradation of TOC in wastewater under relatively mild conditions, achieving significant removal efficiency. In some embodiments, the raw material used for the manganese catalyst material can be derived from manganese dioxide slag generated from hydrometallurgical wastewater, realizing waste recycling.

[0044] The manganese catalyst material of this application has high activity, a simple preparation method, and low preparation cost, and has high economic value.

[0045] The method for treating hydrometallurgical wastewater presented in this application has mild reaction conditions, low reagent costs, simple operation, no need for combined adsorbents for deep removal, and good TOC removal effect. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1 This is a scanning electron microscope image of a manganese catalyst material according to an embodiment of this application; the scale bar in the image is 1 μm. Detailed Implementation

[0048] The present application is further described below with reference to embodiments and examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the protection scope of the appended claims.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0050] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations encompass any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0051] In this document, terms such as "preferred," "better," and "more preferred" are merely descriptions of implementation methods or examples that achieve better results, and should be understood as not constituting a limitation on the scope of protection of this application.

[0052] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0053] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0054] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, optional numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0055] In this application, weight can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0056] One or more embodiments of this application provide a method for preparing a manganese catalyst material, comprising the following steps:

[0057] Manganese dioxide slag, the first additive, and water are mixed to obtain the first mixture;

[0058] The first mixture is heated, filtered to collect the filter residue, and dried to obtain a pre-modified material.

[0059] The pre-modified material and the second additive are mixed to obtain a second mixture;

[0060] The second mixture was ball-milled to obtain the manganese catalyst material;

[0061] The first auxiliary agent includes at least one of a nonionic surfactant and a cationic surfactant;

[0062] The second adjuvant includes polyphosphate compounds.

[0063] The method for preparing the manganese catalyst material in this application utilizes a first additive to modify the surface of manganese dioxide slag, and then improves its surface properties and pore structure through heat treatment to form a pre-modified material. Subsequently, a second additive is introduced, followed by secondary modification and activation through ball milling. The mechanochemical effect of ball milling not only ensures that the second additive is uniformly coated on the material surface, but also further refines the particles, increases the specific surface area, and reduces surface defects. This dual modification strategy works synergistically to construct abundant active sites on the surface of the manganese catalyst material. These active sites can effectively activate oxygen in the air, generating highly oxidizing reactive oxygen species, thereby efficiently oxidizing and decomposing recalcitrant organic matter in wastewater under mild conditions.

[0064] In some embodiments, the manganese dioxide slag is a byproduct of nickel-cobalt hydrometallurgy; and / or,

[0065] The manganese dioxide slag contains ≥98% manganese dioxide by weight.

[0066] In this embodiment, inexpensive manganese dioxide waste residue is used as raw material to achieve "waste treatment", which reduces the preparation cost of the catalyst. At the same time, the process is simple and easy to scale up industrially.

[0067] In some embodiments, the first adjuvant may be selected from surfactants such as hexadecyltrimethylammonium bromide, polysorbate, and sodium dodecylbenzenesulfonate, preferably at least one of hexadecyltrimethylammonium bromide and polysorbate; the second adjuvant may be selected from polyphosphate compounds such as sodium hexametaphosphate, sodium tripolyphosphate, and sodium pyrophosphate, preferably at least one of sodium hexametaphosphate and sodium tripolyphosphate.

[0068] In some embodiments, the weight ratio of the manganese dioxide slag, the first additive, and the water is 1:(0.001-0.01):(40-60); and / or,

[0069] The pre-modified material and the second additive are in a weight ratio of 100:(0.01-1).

[0070] In this embodiment, the manganese dioxide slag, the first additive, and water are in a suitable ratio range, which allows the first additive to more fully and uniformly modify the manganese dioxide slag, further optimizing the catalyst preparation efficiency and final performance.

[0071] For example, the weight ratio of the manganese-containing compound, the first additive, and the water can be selected from any value among 1:0.001:40, 1:0.005:50, and 1:0.01:60; the weight ratio of the pre-modified material and the second additive can be selected from any value among 100:0.01, 100:0.1, 100:0.5, and 100:1.

[0072] In some embodiments, the step of heating the first mixture includes:

[0073] The first mixture is heated at a first temperature for a first time under a first pressure;

[0074] Wherein, the first pressure is 1.9 bar to 10 bar; the first temperature is 120°C to 180°C; and the first time is 2 hours to 20 hours.

[0075] In this embodiment, heating the first mixture at a suitable temperature for a suitable time can regulate the crystal structure transformation and surface hydroxylation degree of manganese dioxide slag, forming a pre-modified material with suitable pore structure and surface chemical properties, which is beneficial to obtaining higher catalytic activity.

[0076] For example, the first pressure can be selected from any value among 1.9 bar, 5 bar, and 10 bar; the first temperature can be selected from any value among 120°C, 150°C, and 180°C; and the first time can be selected from any value among 2h, 6h, and 20h.

[0077] In some embodiments, the step of ball milling the second mixture includes:

[0078] In the presence of ball milling media, the second mixture is ball milled at a first rotation speed for a second time;

[0079] The first rotational speed is 200 rpm to 1000 rpm; the second time is 30 min to 120 min.

[0080] Furthermore, the first rotational speed is 200 rpm to 600 rpm. In this embodiment, ball milling the second mixture at a suitable rotational speed for a suitable time allows the manganese dioxide to be fully activated, which is beneficial for obtaining better dispersibility and activity.

[0081] For example, the first rotational speed can be selected from any value among 200 rpm, 400 rpm, and 1000 rpm; the second time can be selected from any value among 30 min, 60 min, and 120 min.

[0082] In this article, the grinding media can be alumina grinding balls, zirconia grinding balls, stainless steel grinding balls, or other commonly used grinding balls in the field; the diameter of the grinding balls is 5mm-10mm; preferably, grinding balls with a diameter of 5mm and grinding balls with a diameter of 10mm are mixed in a 1:1 ratio to obtain the grinding media.

[0083] In this article, the ball-to-material ratio refers to the ratio of the mass of grinding balls to the mass of the second mixture. A ball-to-material ratio of 1-5 is preferred to ensure more complete activation of manganese dioxide.

[0084] In some embodiments, the drying temperature is 100°C-180°C. For example, the drying temperature can be selected from any value among 100°C, 120°C, and 180°C.

[0085] In some embodiments, the first adjuvant comprises at least one of cetyltrimethylammonium bromide and polysorbate; and / or,

[0086] The second adjuvant includes at least one of sodium hexametaphosphate and sodium tripolyphosphate.

[0087] One or more embodiments of this application also provide a manganese catalyst material prepared by the preparation method described above.

[0088] This manganese catalyst material has a loose and porous structure, high specific surface area and abundant surface active sites, and can efficiently catalyze the degradation of organic matter in wastewater by air oxidation under mild conditions.

[0089] One or more embodiments of this application also provide a method for treating hydrometallurgical wastewater, comprising the following steps:

[0090] After adding the manganese catalyst material mentioned above to the hydrometallurgical wastewater and mixing it, the mixture is stirred at a second temperature for a third time under air circulation conditions.

[0091] The second temperature is 40℃-90℃, and the third time is 0.5h-5h.

[0092] This treatment method uses inexpensive air as an oxidant and can achieve deep removal of TOC from hydrometallurgical wastewater under mild conditions close to ambient temperature and pressure. It does not require the addition of expensive chemical oxidants or combined adsorption processes, is easy to operate, and significantly reduces treatment costs.

[0093] Furthermore, the hydrometallurgical wastewater is the wastewater from nickel-cobalt hydrometallurgical wastewater after valuable metal recovery; and / or,

[0094] The TOC content in the hydrometallurgical wastewater is 200ppm-1000ppm; and / or,

[0095] The manganese catalyst material accounts for 0.5%-2% of the weight of the wastewater.

[0096] In this embodiment, optimizing the catalyst dosage for hydrometallurgical wastewater of specific sources and concentrations can maximize economic benefits while ensuring treatment effectiveness.

[0097] For example, the second temperature can be selected from any value among 40℃, 70℃, and 90℃; the third time can be selected from any value among 0.5h, 2h, and 5h; and the percentage of the manganese catalyst material in the weight of the hydrometallurgical wastewater can be selected from any value among 0.5%, 1%, and 2%.

[0098] The following are some specific examples.

[0099] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0100] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0101] Manganese dioxide slag: a byproduct of the nickel-cobalt hydrometallurgical process, containing 98% manganese dioxide and 2% other metal compounds such as nickel and cobalt. Wastewater is generated from the hydrometallurgical extraction process; after recovering valuable metals, the TOC is between 200ppm and 1000ppm.

[0102] I. Preparation methods of manganese catalyst materials

[0103] Example 1

[0104] This embodiment provides a method for preparing the manganese catalyst material of this application, including the following steps:

[0105] (1) Weigh 5g of manganese dioxide slag, 0.025g of cetyltrimethylammonium bromide (first auxiliary agent) and 250g of deionized water, and stir and mix them at room temperature for 30min to obtain the first mixture.

[0106] (2) Transfer the first mixture to a high-pressure reactor and heat it at 150°C for 6 hours. After cooling to room temperature, filter the mixture and collect the filter residue.

[0107] (3) The filter residue was dried in an oven at 120°C for 12 hours to obtain the pre-modified material.

[0108] (4) Weigh the pre-modified material, add 0.1% of its weight of sodium hexametaphosphate (second auxiliary agent), mix evenly to obtain the second mixture.

[0109] (5) The second mixture was placed in a planetary ball mill, and 5 mm alumina grinding balls and 10 mm zirconia grinding balls were mixed in a 1:1 ratio as the grinding media. The ball-to-material ratio was 1:1. The mixture was ball-milled at 400 rpm for 60 min to obtain the manganese catalyst material, denoted as Cat-1.

[0110] Example 2

[0111] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method in Example 1, except that: the first auxiliary agent is polysorbate (Tween 80, a nonionic surfactant), and its dosage is 0.05g (the weight ratio of manganese dioxide slag is 0.01). The prepared manganese catalyst material is designated as Cat-2.

[0112] Example 3

[0113] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method in Example 1, except that: the second auxiliary agent is sodium tripolyphosphate (a polyphosphate compound), and its amount is 0.5% of the weight of the pre-modified material. The prepared manganese catalyst material is designated as Cat-3.

[0114] Example 4

[0115] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method in Example 1, except that the heating treatment temperature is 120°C and the time is 20 hours. The prepared manganese catalyst material is designated as Cat-4.

[0116] Example 5

[0117] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method in Example 1, except that the ball milling time is 30 min. The prepared manganese catalyst material is designated as Cat-5.

[0118] Example 6

[0119] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method of Example 1, except that: in the wastewater treatment step, the reaction temperature is 50°C, the reaction time is 0.5h, and the catalyst dosage is 0.5% of the weight of the wastewater.

[0120] Example 7

[0121] This embodiment provides a method for preparing the manganese catalyst material of this application, which is basically the same as the preparation method in Example 1, except that: the first auxiliary agent is polysorbate (Tween 80, a nonionic surfactant), and the second auxiliary agent is sodium tripolyphosphate (a polyphosphate compound). The prepared manganese catalyst material is designated as Cat-7.

[0122] Example 8

[0123] This embodiment provides a method for preparing the manganese catalyst material of this application, including the following steps:

[0124] (1) Weigh 5g of manganese dioxide slag, 0.05g of polysorbate (first additive) and 250g of deionized water, and stir and mix them at room temperature for 10min to obtain the first mixture.

[0125] (2) Transfer the first mixture to a high-pressure reactor and heat it at 180°C for 20 hours. After cooling to room temperature, filter the mixture and collect the filter residue.

[0126] (3) The filter residue is dried in an oven at 180°C to obtain the pre-modified material.

[0127] (4) Weigh the pre-modified material, add 1% of its weight of sodium tripolyphosphate (second auxiliary agent), and mix evenly to obtain the second mixture.

[0128] (5) Place the second mixture in a ball mill and ball mill for 120 min to obtain the manganese catalyst material, which is denoted as Cat-8.

[0129] Example 9

[0130] This embodiment provides a method for preparing the manganese catalyst material of this application, including the following steps:

[0131] (1) Weigh 5g of manganese dioxide slag, 0.03g of cetyltrimethylammonium bromide (first auxiliary agent) and 250g of deionized water, and stir and mix them at room temperature for 10min to obtain the first mixture.

[0132] (2) Transfer the first mixture to a high-pressure reactor and heat it at 170°C for 15 hours. After cooling to room temperature, filter the mixture and collect the filter residue.

[0133] (3) The filter residue is dried in an oven at 160°C to obtain the pre-modified material.

[0134] (4) Weigh the pre-modified material, add 0.1% of its weight of sodium hexametaphosphate (second auxiliary agent), mix evenly to obtain the second mixture.

[0135] (5) Place the second mixture in a ball mill and ball mill for 100 min to obtain the manganese catalyst material, which is denoted as Cat-9.

[0136] Example 10

[0137] This embodiment provides a method for preparing the manganese catalyst material of this application, including the following steps:

[0138] (1) Weigh 5g of manganese dioxide slag, 0.01g of sodium stearate (first additive) and 250g of deionized water, and stir and mix them at room temperature for 10min to obtain the first mixture.

[0139] (2) Transfer the first mixture to a high-pressure reactor and heat it at 150°C for 6 hours. After cooling to room temperature, filter the mixture and collect the filter residue.

[0140] (3) The filter residue is dried in an oven at 120°C to obtain the pre-modified material.

[0141] (4) Weigh the pre-modified material, add 0.08% of its weight of triisopropanolamine (second auxiliary agent), mix evenly to obtain the second mixture.

[0142] (5) Place the second mixture in a ball mill and mill for 50 min to obtain the manganese catalyst material, denoted as Cat-10.

[0143] Example 11

[0144] This embodiment provides a method for preparing the manganese catalyst material of this application, including the following steps:

[0145] (1) Weigh 5g of manganese dioxide slag, 0.008g of sodium dodecylbenzenesulfonate (first auxiliary agent) and 250g of deionized water, and stir and mix them at room temperature for 10min to obtain the first mixture.

[0146] (2) Transfer the first mixture to a high-pressure reactor and heat it at 120°C for 3 hours. After cooling to room temperature, filter the mixture and collect the residue.

[0147] (3) The filter residue is dried in an oven at 100°C to obtain the pre-modified material.

[0148] (4) Weigh the pre-modified material, add 0.01% of its weight of triethanolamine (second auxiliary agent), mix evenly to obtain the second mixture.

[0149] (5) Place the second mixture in a ball mill and ball mill for 30 min to obtain the manganese catalyst material, denoted as Cat-11.

[0150] Comparative Example 1

[0151] This comparative example provides another method for preparing a manganese catalyst material, which is basically the same as the preparation method in Example 1, except that no second auxiliary agent (sodium hexametaphosphate) is added during the preparation process; that is, the pre-modified material is directly ball-milled. The prepared material is denoted as Cat-C1.

[0152] Comparative Example 2

[0153] This comparative example provides another method for preparing a manganese catalyst material, which is basically the same as the preparation method in Example 1, except that the first auxiliary agent (hexadecyltrimethylammonium bromide) is not added during the preparation process; that is, the manganese dioxide slag and water are directly mixed for subsequent treatment. The prepared material is denoted as Cat-C2.

[0154] Comparative Example 3

[0155] This comparative example directly uses untreated manganese dioxide slag (from the same source as in Example 1) as a catalyst, denoted as Cat-C3.

[0156] Comparative Example 4

[0157] This comparative example provides another method for preparing a manganese catalyst material, which is basically the same as the preparation method in Example 1, except that the first auxiliary agent is sodium dodecylbenzenesulfonate (anionic surfactant), and its dosage is 0.025 g. The prepared material is designated as Cat-C4.

[0158] Comparative Example 5

[0159] This comparative example provides another method for preparing a manganese catalyst material, which is basically the same as the preparation method in Example 1, except that the second auxiliary agent is sodium citrate (a non-polyphosphate compound), and its amount is 0.1% of the weight of the pre-modified material. The prepared material is denoted as Cat-C5.

[0160] II. Treatment Methods for Hydrometallurgical Wastewater

[0161] The manganese catalyst materials used in the various embodiments and comparative examples were employed to treat hydrometallurgical wastewater. The steps were as follows: 500 mL of nickel-cobalt hydrometallurgical wastewater (with recovered valuable metals and pH between 8 and 9) with an initial TOC concentration of 525 ppm was taken, and 5 g of manganese catalyst material (1% of the wastewater weight) was added. Under continuous air circulation, the temperature was raised to 70°C and the mixture was stirred for 2 hours. After the reaction was completed, the catalyst was separated by filtration, and the TOC concentration of the filtrate was measured.

[0162] III. Performance Testing and Result Analysis

[0163] (1) Surface morphology test

[0164] The manganese catalyst material from Example 1 was subjected to electron microscopy scanning. Figure 1 The image shown is a scanning electron microscope (SEM) image of the manganese catalyst material of Example 1 of this application. Figure 1 It is evident that it exhibits a loose, porous granular structure with abundant micropores.

[0165] (2) TOC removal effect test

[0166] The total organic carbon (TOC) concentration of the wastewater before and after treatment was determined using a total organic carbon (TOC) analyzer. The TOC removal rate was calculated using the following formula: TOC removal rate (%) = [(initial TOC concentration - final TOC concentration) / initial TOC concentration] × 100%.

[0167] Table 1 Test results of the examples and comparative examples

[0168] serial number First adjuvant Second adjuvant Heating conditions (°C / h) Ball milling time (h) Reaction conditions (°C / h) Initial TOC (ppm) Final TOC (ppm) TOC removal rate (%) Example 1 Hexadecyltrimethylammonium bromide (cation) Sodium hexametaphosphate 150 / 6 60 70 / 2 525 28 94.7 Example 2 Polysorbate (nonionic) Sodium hexametaphosphate 150 / 6 60 70 / 2 525 35 93.3 Example 3 Hexadecyltrimethylammonium bromide (cation) Sodium tripolyphosphate 150 / 6 60 70 / 2 525 31 94.1 Example 4 Hexadecyltrimethylammonium bromide (cation) Sodium hexametaphosphate 120 / 20 60 70 / 2 525 42 92.0 Example 5 Hexadecyltrimethylammonium bromide (cation) Sodium hexametaphosphate 150 / 6 30 70 / 2 525 45 91.4 Example 6 Hexadecyltrimethylammonium bromide (cation) Sodium hexametaphosphate 150 / 6 60 50 / 0.5 525 76 85.5 Example 7 Polysorbate (nonionic) Sodium tripolyphosphate 150 / 6 60 70 / 2 525 33 93.7 Example 8 Polysorbate (nonionic) Sodium tripolyphosphate 180 / 20 120 90 / 5 525 16 97.0 Example 9 Hexadecyltrimethylammonium bromide (cation) Sodium hexametaphosphate 170 / 15 100 80 / 4 525 23 95.6 Example 10 Polysorbate (nonionic) Sodium hexametaphosphate 170 / 15 100 80 / 4 525 25 95.2 Comparative Example 1 Hexadecyltrimethylammonium bromide (cation) none 150 / 6 60 70 / 2 525 158 69.9 Comparative Example 2 none Sodium hexametaphosphate 150 / 6 60 70 / 2 525 210 60.0 Comparative Example 3 none none none none 70 / 2 525 380 27.6 Comparative Example 4 Sodium dodecylbenzenesulfonate (anionic) Sodium hexametaphosphate 150 / 6 60 70 / 2 525 265 49.5 Comparative Example 5 Hexadecyltrimethylammonium bromide (cation) Sodium citrate 150 / 6 60 70 / 2 525 195 62.9

[0169] As can be seen from Table 1, Examples 1-11 all exhibited excellent TOC removal effects, with removal rates all above 85%, significantly better than all comparative examples. This indicates that the manganese catalyst material prepared by the method of this application has extremely high catalytic activity. Through stepwise activation, abundant active sites were successfully constructed on the surface of the material, which can efficiently activate oxygen in the air and generate highly oxidizing free radicals, thereby deeply oxidizing and decomposing the organic matter in the wastewater that is difficult to degrade under mild conditions.

[0170] Both Example 1 (cationic surfactant CTAB) and Example 2 (nonionic surfactant Tween 80) exhibited excellent catalytic activity, achieving TOC removal rates of 94.7% and 93.3%, respectively. Example 7, using both a nonionic surfactant and a polyphosphate compound, also achieved a high removal rate of 93.7%. In contrast, Comparative Example 4, using an anionic surfactant (sodium dodecylbenzenesulfonate) as the first auxiliary agent, achieved a TOC removal rate of only 49.5%, far lower than Examples 1 and 2. This demonstrates that using both cationic and nonionic surfactants as the first auxiliary agent allows for effective surface interaction with manganese dioxide, resulting in good dispersion and thus enhancing catalytic activity.

[0171] Both Example 1 (sodium hexametaphosphate) and Example 3 (sodium tripolyphosphate) exhibited high catalytic activity, with TOC removal rates of 94.7% and 94.1%, respectively. In contrast, Comparative Example 5, using sodium citrate (a non-polyphosphate compound) as a second promoter, achieved a TOC removal rate of only 62.9%, significantly lower than Examples 1 and 3. This demonstrates that the second promoter, a polyphosphate compound, forms a phosphate-modified layer on the catalyst surface through mechanochemical action during ball milling, promoting oxygen adsorption and activation, and generating more reactive oxygen species (such as superoxide radicals and hydroxyl radicals), thereby enhancing catalytic activity.

[0172] The TOC removal rates of Comparative Example 1 (without the second additive) and Comparative Example 2 (without the first additive) were 69.9% and 60.0%, respectively, both significantly lower than those of Example 1. This indicates that the first and second additives play irreplaceable roles in the catalyst preparation process, and there is a synergistic effect between them. The first additive disperses and modifies the surface of the manganese dioxide slag in the initial stage, forming a pre-modified material with suitable pore structure and surface chemistry. The second additive forms a phosphate modification layer on the surface of the pre-modified material through a ball milling process, further increasing the active sites. This dual modification strategy works synergistically to construct a highly efficient catalytic system.

[0173] In the embodiments, the performance of Examples 4 and 5 was slightly lower than that of Example 1. Example 4 used a lower heating temperature and a longer time, which may have resulted in a less optimized crystal structure or surface hydroxylation state than in Example 1, leading to a slightly smaller number of active sites. The shorter ball milling time in Example 5 may have resulted in insufficient coating of the second additive and insufficient particle refinement, resulting in a relatively small specific surface area and thus affecting catalytic activity. Nevertheless, their performance was still far superior to the comparative examples, demonstrating that the technical solution of this application can maintain high efficiency over a wide range of process parameters. Example 6 treated wastewater under milder conditions (50°C, 0.5 h), and although the removal rate decreased, it still reached 85.5%, demonstrating the great potential of the method of this application in terms of energy saving and consumption reduction.

[0174] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] The embodiments described above merely illustrate several implementation methods of this application and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Furthermore, it should be understood that after reading the above teachings, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the protection scope of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the protection scope of the appended claims. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A process for the preparation of a manganese catalyst material, characterized in that, The method comprises the following steps: mixing manganese dioxide residue, a first additive and water to obtain a first mixture; subjecting the first mixture to a heating treatment, collecting the residue by filtration, and drying to obtain a pre-modified material; mixing the pre-modified material and a second additive to obtain a second mixture; subjecting the second mixture to a ball milling treatment to obtain the manganese catalyst material; the first additive comprises at least one of a non-ionic surfactant and a cationic surfactant; the second additive comprises a polyphosphate compound.

2. The production method according to claim 1, characterized by, The manganese dioxide residue is a by-product of nickel-cobalt hydrometallurgy; and / or, The manganese dioxide residue comprises ≥98% manganese dioxide by weight.

3. The production method according to claim 1, characterized by, The weight ratio of the manganese dioxide residue, the first additive and the water is 1:(0.001-0.01):(40-60); and / or, The weight ratio of the pre-modified material and the second additive is 100:(0.01-1).

4. The production method according to any one of claims 1 to 3, characterized by, The step of subjecting the first mixture to a heating treatment comprises: heating the first mixture at a first temperature for a first time under a first pressure; wherein the first pressure is 1.9 bar-10 bar; the first temperature is 120℃-180℃, and the first time is 2h-20h.

5. The method of any one of claims 1-3, wherein the method further comprises, The step of subjecting the second mixture to a ball milling treatment comprises: ball milling the second mixture at a first rotational speed for a second time in the presence of a ball milling medium; wherein the first rotational speed is 200rpm-1000rpm; and the second time is 30min-120min.

6. The method of any one of claims 1-3, wherein the method further comprises, The drying temperature is 100℃-180℃.

7. The method of any one of claims 1-3, wherein the method further comprises, The first additive comprises at least one of cetyltrimethylammonium bromide and polysorbate; and / or, The second additive comprises at least one of sodium hexametaphosphate and sodium tripolyphosphate.

8. A manganese catalyst material characterized in that, The manganese catalyst material is prepared by the method of any one of claims 1-7.

9. A method for the treatment of hydrometallurgical wastewater, characterized in that, The method comprises the following steps: adding the manganese catalyst material of claim 8 to the hydrometallurgical wastewater, mixing, and stirring at a second temperature for a third time under the condition of passing air; wherein the second temperature is 40℃-90℃, and the third time is 0.5h-5h.

10. The processing method according to claim 9, characterized in that, The hydrometallurgical wastewater is wastewater after valuable metal recovery from nickel-cobalt hydrometallurgical wastewater; and / or, The TOC content in the hydrometallurgical wastewater is 200ppm-1000ppm; and / or, The manganese catalyst material accounts for 0.5%-2% of the weight of the hydrometallurgical wastewater.

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