Defective iron sulfide-based composite material as well as preparation method and application thereof

Abstract

The invention discloses a defective iron sulfide-based composite material as well as a preparation method and application thereof, and relates to the technical field of environmental materials and wastewater treatment. The preparation method comprises the steps that ball milling is conducted on white iron ore powder, iron powder and a ball milling solution, the ball milling rotating speed is 300-1200 rpm, the time is 1-12 h, and defect type iron sulfide based composite material Fe / FeS2-x slurry is obtained. The invention further discloses the defect-type iron sulfide-based composite material Fe / FeS2-x slurry prepared by the method and application of the defect-type iron sulfide-based composite material Fe / FeS2-x slurry in arsenic-containing wastewater treatment. The defect-type iron sulfide-based composite material Fe / FeS2-x slurry has high selectivity and thorough fixation on arsenic in arsenic-containing wastewater, the arsenic removal rate can reach 99% or above, and the lowest arsenic content in the arsenic-removed liquid is smaller than 0.1 mg / L.

Description

A defective iron sulfide-based composite material, its preparation method and application Technical Field

[0001] This invention belongs to the field of environmental materials and wastewater treatment technology, specifically relating to a defective iron sulfide-based composite material, its preparation method, and its application. Background Technology

[0002] Arsenic-containing wastewater is widely generated in industries such as smelting and chemical processing, posing a serious threat to the ecological environment and human health. Its in-depth treatment has become an urgent problem to be solved in the environmental field.

[0003] Currently, adsorption methods are used to treat arsenic-containing wastewater due to their low cost and ease of operation. However, existing adsorption materials have significant drawbacks: natural mineral materials, although widely available and inexpensive, have stable structures and insufficient active sites, resulting in poor adsorption capacity and selectivity for As(III). Although modification with exogenous sulfiding agents (such as sodium sulfide and elemental sulfur) can improve performance to some extent, it introduces new safety and environmental risks. Artificially synthesized materials, such as various iron sulfides, pure iron materials, iron-based MOFs, and composite metal oxides, exhibit high reactivity, but their synthesis usually relies on expensive reagents and involves cumbersome steps. Furthermore, these materials are prone to oxidation and aggregation, and have poor stability, which restricts their large-scale production and application.

[0004] Existing studies have attempted to achieve iron-sulfur composites through mechanical ball milling or calcination, but these studies mostly remain at the level of physical mixing or simple chemical reactions, failing to achieve precise construction of active sites at the atomic / defect scale and failing to fully consider the engineering feasibility of integrating material preparation and storage. For example, patent CN106669586B (A Fe@FeS2 composite material and its preparation method and application) uses dry ball milling of iron powder and pyrite to prepare Fe@FeS2 core-shell materials. This method is simple, but it is essentially a physical coating and mechanical mixing process that does not change the crystal structure and surface properties of pyrite itself. The adsorption of As(III) is still mainly surface physical adsorption, with limited selectivity, and the material is prone to shell peeling due to oxidation during long-term use, resulting in performance degradation. Patent CN114538556A (A porous FeS material and its preparation method and its application in the purification of arsenic and heavy metal-containing wastewater) prepares porous FeS by high-temperature calcination of iron powder and pyrite. Although this creates a new porous structure and FeS active phase, the high-temperature process consumes a lot of energy, and the specific surface area of ​​the material decreases after calcination, and the active sites are prone to sintering. Patent CN113102761B (A method for preparing composite zero-valent iron materials based on wet ball milling of soluble sulfides) uses a high-concentration soluble sulfide solution for wet ball milling to prepare sulfide zero-valent iron. Although this method solves the oxidation problem of zero-valent iron in ball milling, it relies entirely on external sulfur reagents, resulting in high costs. Furthermore, the treatment of high-concentration sulfide wastewater introduces new environmental burdens, and the process is neither environmentally friendly nor economically viable.

[0005] Therefore, this field urgently needs to achieve fundamental breakthroughs in material design and preparation methods, and seek an innovative strategy that can balance the economic benefits of natural minerals with the high performance of synthetic materials, while ensuring the safety and environmental friendliness of the process itself. Summary of the Invention

[0006] In view of this, this application provides a defective iron sulfide-based composite material, its preparation method and application, with the main purpose of solving the problem that the existing adsorption methods have poor adsorption capacity and selectivity for arsenic.

[0007] To address the aforementioned technical problems, this application provides a method for preparing a defective iron sulfide-based composite material. The method involves ball milling ferrophosphate powder, iron powder, and a ball milling solution at a speed of 300–1200 rpm for 1–12 hours to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

[0008] In some embodiments, the FeS2 content in the precipitated molten iron powder is ≥60wt%, and the mass ratio of FeS2 to the iron powder is 1:(0.1~1.2).

[0009] In some embodiments, the ball milling solution includes a dispersant and a solvent, wherein the dispersant is one or more of polyvinylpyrrolidone solution, polyvinylcaprolactam solution, hydroxypropyl methylcellulose solution, and hydroxyethylcellulose solution; and the solvent is water and / or ethanol.

[0010] In some embodiments, the concentration of the dispersant is 0.1~50 g / L.

[0011] In some embodiments, the ratio of the volume of the ball milling solution to the total mass of the precipitate powder and the iron powder is (2~50): 1 mL / g.

[0012] In some embodiments, the grinding balls of the ball mill are one or more of zirconia balls, alumina balls, and steel balls.

[0013] In some embodiments, the ratio of the mass of the grinding ball to the total mass of the precipitate powder and the iron powder is (10~50):1.

[0014] This application also provides a defective iron sulfide-based composite material Fe / FeS prepared by the aforementioned preparation method. 2-x For slurry, 0.01 < x < 1.

[0015] This application also provides the aforementioned defective iron sulfide-based composite material Fe / FeS. 2-x Application of slurry in the treatment of arsenic-containing wastewater.

[0016] In some embodiments, 2-30 g / L of the defective iron sulfide-based composite material Fe / FeS 2-x The slurry is added to the arsenic-containing wastewater and stirred or shaken at a speed of 50-500 rpm, a reaction temperature of 20-80℃, and a time of 15-120 min.

[0017] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: (1) High selective arsenic capture: Natural argillaceous FeS2 and iron arsenide sulfide crystals have the same structure. By causing argillaceous FeS2 to undergo sulfur depletion in a high-energy, iron-rich environment, defective iron sulfide FeS2 is formed. 2-x In this phase, the vacancy defects are sites reserved for arsenic. The combination with arsenic is the FeAsS forward formation process, which can directly convert arsenic in different valence states in wastewater into highly stable artificial arsenopyrite crystals. This "adsorption-mineralization" synergistic process achieves high selectivity and complete fixation of arsenic, with an arsenic removal rate of over 99%, and the lowest arsenic content in the liquid after arsenic removal is less than 0.1 mg / L.

[0018] (2) Integrated preparation and storage: The defective iron sulfide-based composite material Fe / FeS provided by this invention 2-xThe slurry, prepared by wet ball milling, allows for a high-energy in-situ reaction of ferrous sulfide powder and iron powder to form an unstable FeS structure with vacancy defects. 2-x ; Ferrous sulfide unstable structure FeS 2-x The particulate components are preserved in the dispersion solution to maintain high dispersibility, prevent oxidative decomposition, and maintain reactivity.

[0019] (3) Low-cost preparation: FeS2, which has the same structure as FeAsS, is used as raw material. Through controllable "defect engineering", the inexpensive natural mineral is transformed into a high-performance defective iron sulfide-based composite material, which is inexpensive. The preparation process is realized by wet ball milling, which further transforms the raw material into a highly active arsenic removal material. The process is short, the equipment is stable and reliable, and the storage cost is low. Attached Figure Description

[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 is a process flow diagram of a method for preparing a defective iron sulfide material and its application in arsenic-containing wastewater.

[0021] Figure 2 shows the defective iron sulfide-based Fe / FeS prepared in Example 1. 2-x XRD pattern of the composite material.

[0022] Figure 3 is a SEM image of the defective iron sulfide-based composite material prepared in Example 1.

[0023] Figure 4 shows the XRD results of the arsenic removal slag obtained in Example 1. Detailed Implementation

[0024] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this application pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0025] Example 1 The main raw material involved in this example is pyrite powder, in which FeS2 is 78.36 wt% and the particle size of the pyrite powder is <250 μm; the purity of the iron powder is 99.29 wt% and the particle size of the iron powder is <149 μm; the arsenic-containing wastewater comes from high-arsenic wastewater from a copper smelter, and the main contents are shown in Table 1: Table 1 Arsenic Content of High-Arsenic Wastewater

[0026] As shown in Figure 1, this embodiment provides a method for preparing a defective iron sulfide-based composite material: 7g of pyrite powder and 2g of iron powder are weighed and mixed evenly to obtain a mixed powder; the mixed powder is further mixed with a ball milling solution containing 1g / L polyvinylpyrrolidone (PVP) solution, 50mL of ethanol, and 150mL of water, and then placed in a ball mill jar. 200g of zirconia grinding balls are added, and the mixture is ball-milled at 300rpm for 12h. After ball milling, the grinding balls are separated to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry. Take Fe / FeS 2-x After solid-liquid separation and drying, Fe / FeS was obtained from the slurry. 2-x The XRD pattern is shown in Figure 2, and the SEM image is shown in Figure 3. As can be seen from Figure 2, a large amount of FeS2 was observed. 2-x The presence of characteristic peaks, along with a coarse baseline and low diffraction intensity, indicates the successful preparation of an unstable defect-type iron sulfide-based composite material. Figure 3 shows that the material has uniform particle size, with an average particle size of approximately 150 nm. The particles exhibit irregular geometric shapes and low crystallinity.

[0027] In Example 2, the raw materials, namely pyrite, iron powder, and arsenic-containing solution, were the same as in Example 1.

[0028] This embodiment provides a method for preparing a defective iron sulfide-based composite material: 7g of pyrite powder and 3.5g of iron powder are weighed and mixed evenly to obtain a mixed powder; the mixed powder is further mixed with a ball milling solution containing 50g / L hydroxyethyl cellulose (HEC) solution and 200mL of water, and then placed in a ball mill jar. 150g of alumina grinding balls are added, and the mixture is ball-milled at 450rpm for 8 hours. After ball milling, the grinding balls are separated to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

[0029] In Example 3, the raw materials, namely pyrite, iron powder, and arsenic-containing solution, were the same as in Example 1.

[0030] This embodiment provides a method for preparing a defective iron sulfide-based composite material: 7g of pyrite powder and 8.4g of iron powder are weighed and mixed evenly to obtain a mixed powder; the mixed powder is further mixed with a ball milling solution containing 10g / L polyvinyl caprolactam solution (PVCL), 100mL of ethanol, and 200mL of water, and then placed in a ball mill jar. 560g of zirconia grinding balls are added, and the mixture is ball-milled at 600rpm for 6 hours. After ball milling, the grinding balls are separated to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

[0031] In Example 4, the raw materials, namely pyrite, iron powder, and arsenic-containing solution, were the same as in Example 1.

[0032] This embodiment provides a method for preparing a defective iron sulfide-based composite material, comprising the following steps: weighing 7g of pyrite powder and 0.7g of iron powder and mixing them evenly to obtain a mixed powder; further mixing the mixed powder with a ball milling solution containing 0.1g / L hydroxypropyl methylcellulose (HPMC) and 40mL of ethanol, and then placing the mixture into a ball mill jar, adding 77g of steel grinding balls, and ball milling at 750rpm for 4h. After ball milling, separating the grinding balls to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

[0033] Example 5: In this example, the FeS2 content in the precipitated molten iron powder was 88.47 wt%, and the purity of the iron powder was 93.29 wt%. The arsenic-containing wastewater came from the waste acid wastewater of a zinc smelter. The main contents are shown in Table 2: Table 2 Arsenic Content in Waste Acid Wastewater

[0034] This embodiment provides a method for preparing a defective iron sulfide-based composite material: 7g of pyrite powder and 5g of iron powder are weighed and mixed evenly to obtain a mixed powder; the mixed powder is further mixed with a ball milling solution containing 5g / L polyvinylpyrrolidone (PVP) solution, 200mL of ethanol, and 200mL of water, and then placed in a ball mill jar. 300g of alumina grinding balls are added, and the mixture is ball milled at 900rpm for 1 hour. After ball milling, the grinding balls are separated to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

[0035] Application Example 1: Take 2g of the defective iron sulfide-based composite material Fe / FeS prepared in Example 1. 2-x The slurry was added to 1L of high-arsenic waste acid from a copper smelter and stirred at 300rpm for 60min at 30℃. Afterward, solid-liquid separation was performed to obtain arsenic-removed liquid and arsenic-removed slag. The arsenic content of the arsenic-removed liquid was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), with a residual arsenic concentration of 22.31mg / L, resulting in an arsenic removal rate of 96.11%. The XRD pattern of the arsenic-removed slag is shown in Figure 4, which shows the characteristic diffraction peaks of FeAsS, indicating that arsenic was mineralized and adsorbed.

[0036] Application Example 2: Take 3g of the defective iron-based composite material Fe / FeS prepared in Example 2. 2-x The slurry was added to 1L of high-arsenic waste acid from a copper smelter and stirred at 500rpm for 30min at 60℃. After reaction, solid-liquid separation was performed to obtain arsenic-removed liquid and arsenic-removed slag. The arsenic content of the arsenic-removed liquid was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the residual arsenic concentration was found to be 0.03mg / L, resulting in an arsenic removal rate of 99.99%.

[0037] Application Example 3: Take 5g of the defective iron-based composite material Fe / FeS prepared in Example 3. 2-x The slurry was added to 1L of high-arsenic waste acid from a copper smelter and stirred at 150rpm for 90min at 50℃. After reaction, solid-liquid separation was performed to obtain arsenic-removed liquid and arsenic-removed slag. The arsenic content of the arsenic-removed liquid was detected by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the residual arsenic concentration was 4.67mg / L, with an arsenic removal rate of 99.20% calculated.

[0038] Application Example 4: Take 30g of the defective iron-based composite material Fe / FeS prepared in Example 4. 2-x The slurry was added to 1L of high-arsenic waste acid from a copper smelter and stirred at 250rpm for 15min at 80℃. After the reaction, solid-liquid separation was performed to obtain arsenic-removed liquid and arsenic-removed slag. The arsenic content of the arsenic-removed liquid was detected by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the residual arsenic concentration was 10.25mg / L, with an arsenic removal rate of 98.24% calculated.

[0039] Application Example 5: Take 15g of the defective iron-based composite material Fe / FeS prepared in Example 5. 2-x The slurry was added to 1 L of acidic wastewater from a zinc smelter and stirred at 400 rpm for 120 min at 40°C. After reaction, solid-liquid separation was performed to obtain arsenic-removed liquid and arsenic-removed slag. The arsenic content of the arsenic-removed liquid was detected by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the residual arsenic concentration was 0.52 mg / L, with an arsenic removal rate of 99.91%.

[0040] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0041] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for preparing a defective iron sulfide-based composite material, characterized in that, Marbledite powder, iron powder, and ball milling solution were ball milled at a speed of 300-1200 rpm for 1-12 hours to obtain the defective iron sulfide-based composite material Fe / FeS. 2-x Slurry.

2. The method for preparing the defective iron sulfide-based composite material according to claim 1, characterized in that, The FeS2 content in the precipitated molten iron powder is ≥60wt%, and the mass ratio of FeS2 to the iron powder is 1:(0.1~1.2).

3. The method for preparing the defective iron sulfide-based composite material according to claim 1, characterized in that, The ball milling solution includes a dispersant and a solvent. The dispersant is one or more of polyvinylpyrrolidone solution, polyvinylcaprolactam solution, hydroxypropyl methylcellulose solution, and hydroxyethylcellulose solution. The solvent is water and / or ethanol.

4. The method for preparing the defective iron sulfide-based composite material according to claim 3, characterized in that, The concentration of the dispersant is 0.1~50 g / L.

5. The method for preparing the defective iron sulfide-based composite material according to claim 1, characterized in that, The ratio of the volume of the ball milling solution to the total mass of the precipitate powder and the iron powder is (2~50): 1 mL / g.

6. The method for preparing the defective iron sulfide-based composite material according to claim 1, characterized in that, The grinding balls used in ball mills are one or more of the following: zirconia balls, alumina balls, and steel balls.

7. The method for preparing the defective iron sulfide-based composite material according to claim 1, characterized in that, The ratio of the mass of the grinding ball to the total mass of the precipitated iron ore powder and the iron powder is (10~50):

1.

8. The defective iron sulfide-based composite material Fe / FeS prepared by the preparation method according to any one of claims 1 to 7. 2-x The slurry, characterized in that, 0.01＜x＜1。 9. The defective iron sulfide-based composite material Fe / FeS according to claim 8 2-x Application of slurry in the treatment of arsenic-containing wastewater.

10. The application according to claim 9, characterized in that, The defective iron sulfide-based composite material Fe / FeS with a concentration of 2-30 g / L 2-x The slurry is added to the arsenic-containing wastewater and stirred or shaken at a speed of 50-500 rpm, a reaction temperature of 20-80℃, and a time of 15-120 min.

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