A method for treating acid arsenic-containing wastewater by using electrolytic manganese residue as raw material in cooperation with Fenton-like reaction

Abstract

The application provides a method for treating acid arsenic-containing wastewater by using electrolytic manganese residue as raw material and cooperating with a Fenton-like reaction, and relates to the technical field of wastewater treatment. The method for treating acid arsenic-containing wastewater by using electrolytic manganese residue as raw material and cooperating with a Fenton-like reaction provided by the application comprises the following steps: mixing electrolytic manganese residue and acid arsenic-containing wastewater to obtain As-Mn-containing wastewater to be treated; adjusting the pH value of the As-Mn-containing wastewater to be treated, introducing oxygen, and performing a Fenton-like reaction to obtain a reaction system; and performing solid-liquid separation on the reaction system to obtain arsenic-removed wastewater and arsenic-stabilized products. The application can remove As in acid arsenic-containing wastewater, and simultaneously obtain a solid product with low As leaching rate without causing secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction. Background Technology

[0002] Arsenic pollution in water and soil is a significant environmental problem. Arsenic in water and soil can be exposed to humans through drinking water and food, seriously endangering public health. Acidic oxidizing environments are a key site for arsenic activation and release. Arsenic in the Earth's crust mainly exists as sulfide minerals (such as arsenopyrite and arsenopyrite) associated with metallic sulfide minerals. Non-ferrous metal and coal mining generate large amounts of arsenic-containing waste rock and tailings. The pyrites (such as FeS2 and CuFeS2) contained in these wastes are oxidized under microbial and abiotic processes, producing acidic wastewater (AMD), which releases large amounts of arsenic and other harmful elements, seriously threatening the surrounding water and soil environment and food safety. For example, the pH value of AMD in California iron ore mines typically ranges from 0.02 to 1.5, with extreme acidity reaching -3.6, and arsenic content as high as 850 mg / L, of which trivalent arsenic (As(III)) reaches 84 mg / L. Arsenic (As(III) and As(V)) in AMD can react with SO42-. 2- Fe 3+ Divalent metal cations (such as Fe) 2+ Cu 2+ ,Pb 2+ ,Mn 2+ Arsenic can be reduced by forming amorphous secondary arsenic-containing minerals (including adsorbed arsenic) through chemical reactions such as complexation, adsorption, doping, and precipitation, thereby reducing the mobility and toxicity of arsenic.

[0003] Currently, the main technologies used abroad for treating arsenic-containing acidic mine wastewater include lime neutralization, sulfide precipitation, wastewater treatment technology, and chemical passivation / stabilization. Domestically, the main methods employed are lime neutralization, wastewater treatment technology, and chemical passivation / stabilization. Traditional lime neutralization and wastewater treatment technologies suffer from high remediation costs; while chemical passivation / stabilization technology is relatively economical, simple, and fast, its actual passivation / stabilization effects are subject to secondary pollution risks and are not ideal. Therefore, the number of wastewater remediation technologies that can be engineered is very limited.

[0004] Using chemical redox technology to remediate and treat arsenic-containing acidic mine wastewater is a relatively mature and cost-effective technique. This involves using chemical agents to react with the acidic arsenic-containing mine wastewater through physicochemical processes such as redox, chelation, precipitation, and adsorption. By altering the form of arsenic and reducing its mobility, the remediation effect is achieved. Current technologies primarily use iron-containing substances, alkaline substances, and minerals as stabilizers to convert arsenic in the acidic mine wastewater into arsenic-containing waste residue. However, under natural storage conditions, rainwater leaching or mineral transformation caused by biological and abiotic processes can release arsenic from the smelting waste residue, which then diffuses through surface runoff and groundwater seepage, posing a significant potential hazard to the surrounding water and soil environment. Therefore, it is necessary to develop new industrial wastewater arsenic removal / fixation technologies to improve the stability of arsenic-containing waste residue and stabilize potentially hazardous arsenic-containing waste residue to prevent arsenic pollution. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction. This invention can remove As from acidic arsenic-containing wastewater while obtaining a solid product with a low As leaching rate without generating secondary pollution.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction, comprising the following steps:

[0008] Electrolytic manganese slag and acidic arsenic-containing wastewater are mixed to obtain wastewater containing As(III)-Mn(II) for treatment; the acidic arsenic-containing wastewater includes As 3+ and Fe 2+ ;

[0009] The pH of the wastewater containing As(III)-Mn(II) was adjusted to 3.0-11.0, and oxygen-containing gas was introduced to carry out a Fenton-like reaction to obtain the reaction system.

[0010] The reaction system was subjected to solid-liquid separation to obtain arsenic-removed wastewater and arsenic-stabilized products.

[0011] Preferably, the pH value of the acidic arsenic-containing wastewater is less than 0.5;

[0012] The arsenic content in the acidic arsenic-containing wastewater is 0.35–12.15 g·L⁻¹. -1 .

[0013] Preferably, the molar ratio of As to Mn in the wastewater containing As(III)-Mn(II) is 1 to 100:1, and the molar ratio of Fe to As is 2 to 110:1.

[0014] Preferably, the concentration of As element in the As(III)-Mn(II)-containing wastewater to be treated is 0.15–26 g·L⁻¹. -1 The concentration of Mn is 0.1–9 g·L⁻¹. -1 The concentration of Fe element is 1.6–45 g·L⁻¹. -1 .

[0015] Preferably, the oxygen-containing gas includes air or oxygen; when the oxygen-containing gas is oxygen, the flow rate of the oxygen is not higher than 2.4 L·min. -1 .

[0016] Preferably, the temperature of the Fenton-like reaction is 25–95°C.

[0017] Preferably, the Fenton-like reaction time is 0.05 to 12 hours.

[0018] Preferably, the Fenton-like reaction is carried out under stirring conditions, and the stirring speed is 200-250 r / min.

[0019] Preferably, the solid-liquid separation includes filtration.

[0020] Preferably, the arsenic content in the arsenic removal wastewater is below 0.49 mg / L.

[0021] This invention provides a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as a raw material in conjunction with a Fenton-like reaction. First, electrolytic manganese slag is directly added to the acidic arsenic-containing wastewater to leach Mn(II), forming wastewater containing a high concentration of As(III)-Mn(II). Subsequently, the pH value of the wastewater is precisely controlled, and O2 is introduced into the wastewater, causing a Fenton-like reaction between Fe(II) and O2 in the system. This oxidizes Fe(II) and As(III) in the wastewater system to Fe(III) and As(V), respectively. Simultaneously, Fe(III)... III) co-precipitates with As(V) to form iron oxide minerals. The Mn(II) adsorbed on the surface of the iron oxide minerals can control the oxidation of As(III) to As(V) in the system. Finally, liquid arsenic in the system is adsorbed to form stable arsenic-containing iron oxide minerals, so that the treated arsenic-removed wastewater meets the environmental discharge standards, and the stability of arsenic-containing waste residue is improved, reducing the secondary risk of arsenic migration into the environment. This realizes the "waste-to-waste" treatment of arsenic pollution in electrolytic manganese slag and acidic arsenic-containing wastewater, and provides a new idea for the resource utilization and environmental protection of electrolytic manganese slag and acidic arsenic-containing wastewater.

[0022] The arsenic-removing wastewater treated using the method of this invention is 0.5 mg·L lower than the Chinese wastewater discharge limit. -1 Furthermore, it generates stable low-As leaching solid products, reducing the risk of secondary pollution. This was achieved at a pH of 5–8, a temperature of 25–95℃, and an oxygen flow rate of 1.6 L / min. -1 Under the specified conditions, the arsenic removal rate within 8 hours is over 99.4%. This wastewater arsenic removal method has advantages such as high efficiency, environmental friendliness, simple operation, strong adaptability, great potential for resource utilization, and good economic benefits, making it a wastewater treatment technology with broad application prospects.

[0023] The results of the examples show that the main solid product generated after treatment by the method of the present invention is As-containing hexahydrite, which has a low As leaching fixation rate, making it easy to carry out subsequent safe disposal. Attached Figure Description

[0024] Figure 1 A schematic diagram of a process for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction.

[0025] Figure 2 This is a schematic diagram illustrating the effect of different treatment conditions on the As removal rate of acidic arsenic-containing wastewater.

[0026] Figure 3 This is a schematic diagram illustrating the effect of different treatment conditions on the final solid TCLP test results of acidic arsenic-containing wastewater. Detailed Implementation

[0027] This invention provides a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction, comprising the following steps:

[0028] Electrolytic manganese slag and acidic arsenic-containing wastewater are mixed to obtain wastewater containing As(III)-Mn(II) for treatment; the acidic arsenic-containing wastewater includes As 3+ and Fe 2+ ;

[0029] The pH of the wastewater containing As(III)-Mn(II) was adjusted to 3.0-11.0, and oxygen-containing gas was introduced to carry out a Fenton-like reaction to obtain the reaction system.

[0030] The reaction system was subjected to solid-liquid separation to obtain arsenic-removed wastewater and arsenic-stabilized products.

[0031] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials or reagents used, and commercially available products well known to those skilled in the art can be used.

[0032] This invention mixes electrolytic manganese slag with acidic arsenic-containing wastewater to obtain wastewater containing As(III)-Mn(II) for treatment. In this invention, the electrolytic manganese slag preferably comprises MnO and Fe2O3. This invention does not have a specific limitation on the source of the electrolytic manganese slag; electrolytic manganese slag from sources well known in the art can be used.

[0033] In this invention, the source of the acidic arsenic-containing wastewater can be arsenic-containing acidic mine wastewater. In this invention, the acidic arsenic-containing wastewater includes As. 3+ and Fe 2+ In this invention, the pH value of the acidic arsenic-containing wastewater is preferably less than 0.5. In this invention, the arsenic content in the acidic arsenic-containing wastewater is preferably 0.35–12.15 g·L⁻¹. -1 .

[0034] The present invention does not have any particular limitation on the method of mixing the electrolytic manganese slag and the acidic arsenic-containing wastewater, as long as the electrolytic manganese slag is completely dissolved in the acidic arsenic-containing wastewater.

[0035] In this invention, the molar ratio of As to Mn in the wastewater containing As(III)-Mn(II) is preferably 1 to 100:1, specifically 1:1; the molar ratio of Fe to As is preferably 2 to 110:1, specifically 8:1.

[0036] In this invention, the concentration of As element in the wastewater containing As(III)-Mn(II) is preferably 0.15–26 g·L⁻¹. -1 Specifically, it can be 1.5 g·L -1 The preferred concentration of Mn is 0.1–9 g·L⁻¹. -1 Specifically, it can be 1.1 g·L -1 The preferred concentration of Fe is 1.6–45 g·L⁻¹. -1 Specifically, it can be 8.96 g·L -1 .

[0037] After obtaining the wastewater containing As(III)-Mn(II), the present invention adjusts the pH value of the wastewater containing As(III)-Mn(II) to 3.0-11.0, introduces oxygen-containing gas, and carries out a Fenton-like reaction to obtain a reaction system.

[0038] In this invention, the reagent used to adjust the pH value of the As(III)-Mn(II)-containing wastewater is preferably an inorganic alkali, which preferably includes NaOH or Ca(OH)2. The appropriate reagent can be selected according to specific circumstances, and the difference has little impact on the arsenic removal effect. In this invention, the inorganic alkali is preferably used in the form of an inorganic alkali solution, and the concentration of the inorganic alkali solution is preferably 0.1 mol / L. In this invention, the pH value of the As(III)-Mn(II)-containing wastewater can be adjusted to 5.0–9.0.

[0039] In this invention, the oxygen-containing gas preferably includes air or oxygen; when the oxygen-containing gas is air, the flow rate of the air is not specifically limited, and it can be directly exposed to air; when the oxygen-containing gas is oxygen, the flow rate of the oxygen is preferably not higher than 2.4 L·min. -1 Specifically, it can be 0.4 L·min -1 0.8 L·min -1 1.6L·min -1 2.4L·min -1 The higher the oxygen flow rate described in this invention, the better, to ensure a sufficient oxygen supply.

[0040] In this invention, the preferred temperature for the Fenton-like reaction is 25–95°C. In a specific embodiment, the temperature for the Fenton-like reaction can be 80–95°C.

[0041] In this invention, the Fenton-like reaction time is preferably 0.05 to 12 hours, more preferably 0.25 to 8 hours, and in a specific embodiment, the Fenton-like reaction time can be 0.5 to 2 hours.

[0042] In this invention, the Fenton-like reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 200-250 r / min. In a specific embodiment, the stirring speed can be 200-230 r / min.

[0043] After obtaining the reaction system, the present invention performs solid-liquid separation to obtain arsenic-removed wastewater and arsenic stabilization products. The present invention does not have specific limitations on the method of solid-liquid separation, as long as it can remove the generated solid precipitate. In a specific embodiment of the present invention, the solid-liquid separation can be filtration.

[0044] In this invention, the arsenic content in the arsenic removal wastewater is preferably below 0.49 mg / L.

[0045] The arsenic stabilization product obtained by this invention is mainly As-containing hexahydrite, which has a low As leaching fixation rate, facilitating subsequent safe disposal.

[0046] In a specific embodiment of the present invention, the mechanism of using electrolytic manganese slag as raw material in a synergistic Fenton-like reaction to treat acidic arsenic-containing wastewater is as follows:

[0047] Fe 2+ +O2→Fe 3+ +O2 ·- ;

[0048] Fe 2+ +O2 ·- +2H₂O→Fe 3+ +H₂O₂ + 2OH⁻ - ;

[0049] Fe 2+ +H₂O₂→Fe 3+ +OH - +HO · ;

[0050] Fe 2+ +HO · →Fe 3+ +OH - ;

[0051] As 3+ +O2+HO · →As 5+ +O2 ·- ;

[0052] As 3+ +O2 ·- +HO · +2H₂O→As 5+ +H₂O₂ + 3OH⁻ - ;

[0053] As 3+ +2H₂O₂→As 5+ +2OH - ;

[0054] 2MnO2+H3AsO3+H2O→2MnOOH+H2AsO4 - +H + ;

[0055] 2MnOOH + H3AsO3 → 2MnO + H2AsO4 - +H + +H2O.

[0056] The method provided by this invention enables the resource utilization of electrolytic manganese slag, significantly reduces the toxicity and migration of As, avoids secondary pollution caused by As release, and achieves low-cost removal of As from acidic mine wastewater.

[0057] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0058] The schematic diagram of the process for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction in this invention is shown below. Figure 1 As shown.

[0059] The tested acidic arsenic-containing wastewater was a laboratory-simulated Fe-As-S wastewater system, prepared as follows: FeSO4·7H2O and NaAsO2 were dissolved in dilute sulfuric acid with a pH of 1 to prepare Fe(II) and As(III) stock solutions, respectively; arsenic-containing wastewater with concentrations of 8.96 g·L⁻¹ was then used to prepare Fe(II) and As(III) stock solutions. -1 and 1.5 g·L -1 Fe(II) stock solution and As(III) stock solution were mixed to simulate acidic arsenic-containing wastewater with high concentration of As(III).

[0060] The test standard material contains arsenic-containing hexamerite, and its preparation method is as follows:

[0061] A 0.1M Fe(II) solution was kept at 70°C for 10 minutes and then rapidly cooled in an ice bath to form hexamethylenetetramine. Arsenite and arsenate solutions were added to a slurry with a Fe / As molar ratio of 8, the pH was adjusted to about 7.5 with NaOH, and the mixture was stabilized for 24 hours to obtain hexamethylenetetramine containing As(III) and As(V). All the obtained solids were collected by centrifugation, washed three times with distilled water, and then freeze-dried for use.

[0062] The test standard material contains arsenic fibrous iron oxide, and its preparation method is as follows:

[0063] Add 4g FeCl2·4H2O to 100mL of deionized water, and then continuously add NaOH solution (1mol / L, 30mL) to the solution under magnetic stirring and long-term aeration to maintain the pH value within the range of 6.7-6.8 for 3h; after the oxidation reaction is completed, a suspension is generated; for ferrihydrite containing As(III) and As(V), arsenite solution (specifically NaAsO2 solution) and arsenate solution (specifically Na3AsO4 solution) are respectively magnetically stirred with fresh ferrihydrite (Fe / As molar ratio of 8) at pH 7.5 for 24h; collect all the obtained solids by centrifugation, wash three times with distilled water, and then freeze-dry for use.

[0064] The test standard material, magnetite, is prepared as follows:

[0065] Under mechanical stirring, the pH of a mixed solution of Fe(III) and Fe(II) with a Fe(III) / Fe(II) molar ratio of 2 was rapidly adjusted to 9-10 using NaOH, and the resulting black precipitate was aged for 3 days to convert the initial amorphous Fe3O4 into magnetite. All the obtained solids were collected by centrifugation, washed three times with distilled water, and then freeze-dried for use.

[0066] Example 1

[0067] First, electrolytic manganese slag was directly added to artificially simulated acidic arsenic-containing wastewater. Then, 0.1M NaOH solution was added as a neutralizing agent to the prepared simulated wastewater to adjust the pH of the wastewater system to 8. Simultaneously, the system temperature was strictly controlled at 95℃ using a circulating hydrothermal system. Then, at a rate of 1.6 L·min... -1 Oxygen flow rate was used to introduce O2 into the wastewater, causing Fe(II) in the system to undergo a Fenton-like reaction with O2. Finally, after a specific period of redox and complexation precipitation reactions, the liquid-phase arsenic in the system was adsorbed, forming stable arsenic-containing iron oxide minerals. During the 8-hour treatment, two equal aliquots of the suspension were collected at fixed time intervals and then filtered through a 0.22 μm filter membrane. One sample of the filter residue was dissolved in a 6 mol / L HCl solution, and the concentrations of total As (As(T)), As(III), total Fe (Fe(T)), Fe(II), and total Mn (Mn(T)) were analyzed. The other sample of the filter residue was used to characterize the material structure.

[0068] Example 2

[0069] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 5, while the rest is the same as Example 1.

[0070] Example 3

[0071] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 6, while the rest is the same as Example 1.

[0072] Example 4

[0073] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 7, while the rest is the same as Example 1.

[0074] Example 5

[0075] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 9, while the rest is the same as Example 1.

[0076] Example 6

[0077] The difference from Example 1 is that the wastewater system temperature is adjusted to 25°C, while the rest is the same as Example 1.

[0078] Example 7

[0079] The difference from Example 1 is that the wastewater system temperature is adjusted to 35°C, while the rest is the same as Example 1.

[0080] Example 8

[0081] The difference from Example 1 is that the wastewater system temperature is adjusted to 50°C, while the rest is the same as Example 1.

[0082] Example 9

[0083] The difference from Example 1 is that the wastewater system temperature is adjusted to 65°C, while the rest is the same as Example 1.

[0084] Example 10

[0085] The difference from Example 1 is that the wastewater system temperature is adjusted to 80°C, while the rest is the same as Example 1.

[0086] Example 11

[0087] The difference from Example 1 is that the O2 flow rate is adjusted to 0 L / min. -1 That is, the reaction is carried out in the air, and the rest is the same as in Example 1.

[0088] Example 12

[0089] The difference from Example 1 is that the O2 flow rate is adjusted to 0.4 L / min. -1 The rest of the content is the same as in Example 1.

[0090] Example 13

[0091] The difference from Example 1 is that the O2 flow rate is adjusted to 0.8 L·min. -1 The rest of the content is the same as in Example 1.

[0092] Example 14

[0093] The difference from Example 1 is that the O2 flow rate is adjusted to 2.4 L / min. -1 The rest of the content is the same as in Example 1.

[0094] Example 15

[0095] The difference from Example 1 is that Ca(OH)2 is used instead of NaOH as the base, while the rest is the same as Example 1.

[0096] Performance testing

[0097] The concentrations of As(T) and As(III) were analyzed using a hydride generation-atomic fluorescence spectrophotometer (AFS-2202E, Haiguang, China); the concentrations of Fe(T) and Mn(T) were quantified using flame atomic absorption spectrometry; the concentration of Fe(II) was determined using the iron-zinc method at 510 nm using a UV-Vis spectrophotometer (UV-2550, Shimadzu, Japan). NaF was added to the sample to mask the interference of Fe(III); a Quanta 250 scanning electron microscope coupled with an energy dispersive spectroscopy microprobe (SEM-EDS; FEI, USA) was used for solid-state spectra and the Fe / As molar ratio; a D / max 2000PC X-ray diffractometer (XRD; Rigaku, Japan) was used with CuKa 1 radiation (…). 56 kV, 182 mA), with a step scan range of 5°–80° or 10°–80°2θ and a step size of 0.02°2θ, powder X-ray diffraction patterns were recorded to identify the solid phase; a Nicolai 6700 Fourier transform infrared spectrometer (FTIR; Thermo Fisher Scientific, USA) was used in the range of 400–4000 cm⁻¹. -1 Within the wavelength range of 4cm -1 The functional groups of the solid were distinguished by resolution; KBr / sample thin sections were prepared by mixing 0.5% of finely ground sample into KBr. The chemical states and possible speciations of As, Fe, and Mn in the solid product were identified using K-Alpha+ X-ray photoelectron spectroscopy (XPS; Thermo Fisher Scientific, USA) with Al Ka ​​X-rays as the radiation source; toxicity leaching of the solid product was performed according to GB5085.3-2007 (Standard for Identification of Solid Waste - Leaching Toxicity Identification).

[0098] Figure 2 This is a schematic diagram illustrating the effect of different treatment conditions on the removal rate of arsenic-containing acidic wastewater; (from...) Figure 2It is evident that the removal efficiency and equilibrium time of arsenic are strongly controlled by pH. According to Examples 2-4, the arsenic removal efficiency showed an immediate increase with pH from 5 to 7, reaching near equilibrium within 2 hours. However, according to Examples 1 and 5, the As removal rate showed a rapid increase to its maximum value (99.9% and 99.7%) within 0.25 hours with pH increasing from 8 to 9, then gradually decreased to 99.4% and 92.6%. After 8 hours of reaction, the As removal rate decreased from 100% to 92.6% as pH increased from 5 to 9. The arsenic removal rate was less affected by temperature, oxygen flow rate, and neutralizing agent. Within 0.25 hours, almost all As was removed from the aqueous phase, with a removal rate of 99.1%–100% at the end of the experiment. This was achieved at pH 5–8, temperatures of 25–95°C, and an oxygen flow rate of 1.6 L / min. -1 Under these conditions, the removal rate of arsenic can reach over 99.4% within 8 hours.

[0099] Figure 3 This is a schematic diagram illustrating the impact of different treatment conditions on the final solid TCLP test results of acidic arsenic-containing wastewater; (from...) Figure 3 It can be seen that, except for Example 11: the oxygen flow rate is 0 L / min -1 (0.4~4.2mg·L -1 Except for the cases described above, the leaching concentration of As(T) under the other embodiment conditions was below the standard limit of 5 mg·L⁻¹ for arsenic. -1 This demonstrates that short-term storage of high-arsenic solid precipitates in the environment results in low-arsenic leaching. In contrast, the As leaching concentrations in the final solids of Mn(II)-free As(III)-rich AMD and high-As(III)-rich acidic effluents with added high Fe(III) ranged from 23 to 837 mg·L⁻¹. -1 The values ​​far exceeded the standard TCLP test limits. The results indicate that the presence of Mn(II) significantly improved the stability of As leaching from the arsenic removal treatment products.

[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material in conjunction with a Fenton-like reaction, characterized in that, Includes the following steps: Electrolytic manganese slag and acidic arsenic-containing wastewater are mixed to obtain wastewater containing As(III)-Mn(II) for treatment; the acidic arsenic-containing wastewater includes As 3+ and Fe 2+ ; The pH of the wastewater containing As(III)-Mn(II) was adjusted to 3.0~11.0, and oxygen-containing gas was introduced to carry out a Fenton-like reaction to obtain the reaction system. The reaction system was subjected to solid-liquid separation to obtain arsenic-removed wastewater and arsenic-stabilized products. The pH value of the acidic arsenic-containing wastewater is less than 0.5; The arsenic content in the acidic arsenic-containing wastewater is 0.35~12.15 g·L. -1 The molar ratio of As to Mn in the As(III)-Mn(II)-containing wastewater to be treated is 1~100:1, and the molar ratio of Fe to As is 2~110:1; the oxygen-containing gas includes air or oxygen; when the oxygen-containing gas is oxygen, the flow rate of the oxygen is not higher than 2.4 L·min -1 .

2. The method according to claim 1, characterized in that, The concentration of As element in the wastewater containing As(III)-Mn(II) to be treated is 0.15~26 g·L. -1 The concentration of Mn is 0.1~9 g·L. -1 The concentration of Fe element is 1.6~45 g·L. -1 .

3. The method according to claim 1, characterized in that, The temperature range for the Fenton-like reaction is 25~95℃.

4. The method according to claim 1 or 3, characterized in that, The Fenton-like reaction time is 0.05~12h.

5. The method according to claim 1, characterized in that, The Fenton-like reaction is carried out under stirring conditions, and the stirring speed is 200~250 r / min.

6. The method according to claim 1, characterized in that, The solid-liquid separation includes filtration.

7. The method according to claim 1, characterized in that, The arsenic content in the arsenic removal wastewater is below 0.49 mg / L.

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