Method for treating acidic arsenic-containing wastewater by taking electrolytic manganese residue as raw material and cooperating with Fenton-like reaction

Abstract

The invention provides a method for treating acidic arsenic-containing wastewater by taking electrolytic manganese residues as a raw material and cooperating with a Fenton-like reaction, and relates to the technical field of wastewater treatment. The method for treating the acidic arsenic-containing wastewater by taking the electrolytic manganese residues as the raw materials and cooperating with the Fenton-like reaction comprises the following steps: mixing the electrolytic manganese residues and the acidic 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 carrying out a Fenton-like reaction to obtain a reaction system; and carrying out solid-liquid separation on the reaction system to obtain arsenic-removed wastewater and an arsenic-stabilized product. According to the method, As in the acidic arsenic-containing wastewater can be removed, and meanwhile, a solid product with a low As leaching rate is obtained without secondary pollution.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for treating acidic arsenic-containing wastewater by using electrolytic manganese slag as a raw material and coordinating a Fenton-like reaction. Background Art

[0002] Arsenic pollution in water and soil is an important environmental issue. Arsenic in water and soil can be exposed to the human body through drinking water and food, seriously endangering the health of residents. Among them, acidic oxidizing environment is an important place for the activation and release of arsenic. Arsenic in the earth's crust mainly coexists (symbiotically) with metal sulfide ores in the form of sulfide minerals (such as arsenopyrite, arsenopyrite, etc.). Non-ferrous metal and coal mining will produce a large amount of arsenic-containing waste rock and tailings. The pyrite (such as FeS2, CuFeS2, etc.) contained in them will oxidize to produce acidic wastewater (AMD) under the action of microorganisms and non-biological factors, while releasing a large amount of arsenic and other harmful elements, causing serious harm to the surrounding water and soil environment and food safety. For example, the pH value of AMD in iron mines in California, USA is usually between 0.02 and 1.5, and the extremely acidic pH can reach -3.6. The arsenic content is 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 SO4 2- , Fe 3+ , divalent metal cations (such as Fe 2+ ,Cu 2+ ,Pb 2+ ,Mn 2+ ) etc. form 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] At present, the technologies used in foreign countries to treat arsenic acid mine wastewater are mainly lime neutralization, sulfide precipitation, wastewater treatment technology and chemical passivation / stabilization, etc., while domestic technologies mainly use lime neutralization, wastewater treatment technology and chemical passivation / stabilization, etc. Traditional lime neutralization and wastewater treatment technologies have the problem of high repair costs; while chemical passivation / stabilization technology is relatively economical, simple and fast, but the actual passivation / stabilization effect has the potential for secondary pollution and unsatisfactory results, so the wastewater remediation technology that can be engineered is very limited.

[0004] The use of chemical redox technology to repair and treat arsenic-containing acid mine wastewater is a relatively mature and cost-effective technology. Chemical agents are used to undergo physical and chemical reactions such as redox, chelation, precipitation, and adsorption with acid mine arsenic-containing wastewater, and the mobility of arsenic is reduced by changing the occurrence form of arsenic, thereby achieving the effect of repair and treatment. The existing technology mainly uses iron-containing substances, alkaline substances, minerals, etc. as stabilizers to convert arsenic in acid mine wastewater into arsenic-containing waste slag. However, under the natural storage conditions of arsenic-containing waste slag, the mineral form transformation caused by rainwater leaching or biological and non-biological effects can cause the arsenic in the smelting waste slag to be released and diffused with surface runoff and underground seepage, causing huge potential harm to the surrounding water and soil environment. Therefore, it is necessary to develop new industrial wastewater arsenic removal / arsenic fixation technology to improve the stability of arsenic-containing waste slag, and stabilize arsenic-containing waste slag with hidden dangers in the environment to prevent arsenic pollution. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material and coordinating with Fenton-like reaction. The present invention can remove As in acidic arsenic-containing wastewater and obtain a solid product with low As leaching rate without causing secondary pollution.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for treating acidic arsenic-containing wastewater by using electrolytic manganese slag as a raw material and coordinating a Fenton-like reaction, comprising the following steps:

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

[0009] The pH value of the wastewater containing As(III)-Mn(II) to be treated is adjusted to 3.0-11.0, oxygen-containing gas is introduced, and a Fenton-like reaction is carried out to obtain a reaction system;

[0010] The reaction system is subjected to solid-liquid separation to obtain arsenic removal wastewater and arsenic stabilization products.

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

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

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

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

[0015] Preferably, the oxygen-containing gas comprises 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 comprises filtration.

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

[0021] The present invention provides a method for treating acidic arsenic-containing wastewater by using electrolytic manganese slag as a raw material and coordinating a Fenton-like reaction. The present invention firstly uses electrolytic manganese slag to directly add into acidic arsenic-containing wastewater to leach Mn(II), so as to form wastewater to be treated containing high concentration of As(III)-Mn(II); then, the pH value of the wastewater to be treated is finely regulated, and O2 is charged into the wastewater to be treated, so as to cause Fe(II) in the system to undergo a Fenton-like reaction with O2, so that Fe(II) and As(III) in the wastewater system are oxidized to Fe(III) and As(V), respectively. Meanwhile, Fe( III) co-precipitates with As(V) to form iron oxide minerals, and 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, the liquid arsenic in the system is adsorbed to form stable arsenic-containing iron oxide minerals, so that the treated arsenic-removal wastewater meets the environmental emission standards, and the stability of the arsenic-containing waste residue is improved, reducing the secondary risk of arsenic migration to the environment, and realizing the "waste treatment with waste" for arsenic pollution in electrolytic manganese slag and acidic arsenic-containing wastewater, providing a new idea for the resource utilization and environmental protection of electrolytic manganese slag and acidic arsenic-containing wastewater.

[0022] The arsenic removal wastewater treated by the method of the present invention is lower than the sewage discharge limit of 0.5 mg·L in my country. -1 , and generate stable low-As leaching solid products, reducing the risk of secondary pollution. At pH 5-8, temperature 25-95°C, oxygen flow rate 1.6L·min -1 Under the conditions of , the removal rate of arsenic within 8 hours is more than 99.4%. The wastewater arsenic removal treatment method has the advantages of high efficiency, environmental friendliness, simple operation, strong adaptability, great resource utilization potential and good economy. It is a wastewater treatment technology with broad application prospects.

[0023] The results of the embodiment show that after being treated by the method of the present invention, the main solid product generated is As-containing hexahydrite, which has a low As leaching and fixation rate and is convenient for subsequent safe disposal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the process of treating acidic arsenic-containing wastewater using electrolytic manganese slag as raw material and Fenton-like reaction;

[0025] Figure 2 Schematic diagram of the effect of different treatment conditions on As removal rate of acidic arsenic-containing wastewater;

[0026] Figure 3 Schematic diagram of the impact of different treatment conditions on the final solid TCLP test results of acidic arsenic-containing wastewater. DETAILED DESCRIPTION

[0027] The present invention provides a method for treating acidic arsenic-containing wastewater by using electrolytic manganese slag as a raw material and coordinating a Fenton-like reaction, comprising the following steps:

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

[0029] The pH value of the wastewater containing As(III)-Mn(II) to be treated is adjusted to 3.0-11.0, oxygen-containing gas is introduced, and a Fenton-like reaction is carried out to obtain a reaction system;

[0030] The reaction system is subjected to solid-liquid separation to obtain arsenic removal wastewater and arsenic stabilization products.

[0031] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials or reagents used, and commercially available products known to those skilled in the art can be used.

[0032] The present invention mixes electrolytic manganese slag and acidic arsenic-containing wastewater to obtain wastewater to be treated containing As(III)-Mn(II). In the present invention, the electrolytic manganese slag preferably includes MnO and Fe2O3. The present invention has no special limitation on the source of the electrolytic manganese slag, and electrolytic manganese slag from sources well known in the art can be used.

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

[0034] The present invention has no special 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 the present invention, the molar ratio of As element to Mn element in the wastewater to be treated containing As(III)-Mn(II) is preferably 1-100:1, specifically 1:1; the molar ratio of Fe element to As element is preferably 2-110:1, specifically 8:1.

[0036] In the present invention, the concentration of As in the wastewater to be treated containing As(III)-Mn(II) is preferably 0.15 to 26 g·L -1 , specifically 1.5 g·L -1 The concentration of Mn element is preferably 0.1 to 9 g·L -1 , specifically 1.1 g·L -1 The concentration of Fe element is preferably 1.6 to 45 g·L -1 , specifically 8.96 g·L -1 .

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

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

[0039] In the present 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 the air can be directly exposed to the 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 0.4L·min -1 、0.8L·min -1 、1.6L·min -1 、2.4L·min -1 The flow rate of oxygen introduced in the present invention is as large as possible to ensure sufficient oxygen supply.

[0040] In the present invention, the temperature of the Fenton-like reaction is preferably 25 to 95°C. In a specific embodiment, the temperature of the Fenton-like reaction can be 80 to 95°C.

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

[0042] In the present 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 on the reaction system to obtain arsenic removal wastewater and arsenic stabilization product. The present invention has no particular limitation on the method of solid-liquid separation, as long as the generated solid precipitate can be removed. In a specific embodiment of the present invention, the solid-liquid separation can be filtration.

[0044] In the present invention, the content of arsenic in the arsenic removal wastewater is preferably less than 0.49 mg / L.

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

[0046] In a specific embodiment of the present invention, the mechanism of treating acidic arsenic-containing wastewater by using electrolytic manganese slag as raw material and coordinating with Fenton-like reaction 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 the present invention utilizes electrolytic manganese slag as a resource, significantly reduces the toxicity and mobility of As, avoids secondary pollution caused by the release of As, and realizes low-cost removal of As in acid mine wastewater.

[0057] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The schematic diagram of the process of treating acidic arsenic-containing wastewater by using electrolytic manganese slag as raw material and coordinating with Fenton-like reaction in the present invention is as follows: Figure 1 shown.

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

[0060] The test standard substance is arsenic-containing hexahydrite, and the preparation method is as follows:

[0061] A 0.1 M Fe(II) solution was maintained at 70°C for 10 minutes and then quenched in an ice bath to form hexahydrite; arsenite and arsenate solutions were added to a slurry with a Fe / As molar ratio of 8, respectively, and the pH was adjusted to about 7.5 with NaOH and stabilized for 24 hours to obtain hexahydrite 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 substance contains arsenic lepidocrocite, and the preparation method is as follows:

[0063] 4 g of FeCl2·4H2O was added to 100 mL of deionized water, and then NaOH solution (concentration of 1 mol / L, 30 mL) was continuously added to the solution through long-term aeration under magnetic stirring to maintain the pH value in the range of 6.7 to 6.8 for 3 h; a suspension was produced after the oxidation reaction was completed; for lepidocrocite containing As(III) and As(V), arsenite solution (specifically NaAsO2 solution) and arsenate solution (specifically Na3AsO4 solution) were magnetically stirred with fresh lepidocrocite (Fe / As molar ratio of 8) at pH 7.5 for 24 h; all the obtained solids were collected by centrifugation, washed three times with distilled water, and then freeze-dried for use.

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

[0065] Under mechanical stirring, a mixed solution of Fe(III) and Fe(II) with a Fe(III) / Fe(II) molar ratio of 2 was quickly adjusted to a pH of 9-10 with NaOH, and the resulting black precipitate was aged for 3 days to convert the initial amorphous Fe3O4 into magnetite; all the resulting 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 into artificially simulated acidic arsenic-containing wastewater, and then 0.1 M NaOH solution was added into the prepared simulated wastewater as a neutralizer, and the pH value of the wastewater system was adjusted to 8. At the same time, the system temperature was strictly controlled at 95 °C by a circulating hydrothermal system. Then, the temperature was adjusted to 1.6 L min -1 O2 was added to the wastewater at an oxygen flow rate of 1000 μg / cm2, causing a Fenton-like reaction between Fe(II) and O2 in the system. Finally, after a specific period of redox and complex precipitation, the liquid arsenic in the system was adsorbed to form a stable arsenic-containing iron oxide mineral. During the 8-hour treatment, aliquots of the suspension were collected in duplicate at fixed time intervals and then filtered through a 0.22 μm filter membrane. One portion of the filter residue was dissolved in a 6 mol / L HCl solution and analyzed for total As (As(T)), As(III), total Fe (Fe(T)), Fe(II) and total Mn (Mn(T)) concentrations, while the other portion 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, and the rest of the contents are consistent with Example 1.

[0070] Example 3

[0071] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 6, and the rest of the contents are consistent with Example 1.

[0072] Example 4

[0073] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 7, and the rest of the contents are consistent with Example 1.

[0074] Example 5

[0075] The difference from Example 1 is that the pH value of the wastewater system is adjusted to 9, and the rest of the contents are consistent with Example 1.

[0076] Example 6

[0077] The difference from Example 1 is that the temperature of the wastewater system is adjusted to 25° C., and the rest of the contents are consistent with Example 1.

[0078] Example 7

[0079] The difference from Example 1 is that the temperature of the wastewater system is adjusted to 35° C., and the rest of the contents are consistent with Example 1.

[0080] Example 8

[0081] The difference from Example 1 is that the temperature of the wastewater system is adjusted to 50° C., and the rest of the contents are consistent with Example 1.

[0082] Example 9

[0083] The difference from Example 1 is that the temperature of the wastewater system is adjusted to 65° C., and the rest of the contents are consistent with Example 1.

[0084] Example 10

[0085] The difference from Example 1 is that the temperature of the wastewater system is adjusted to 80° C., and the rest of the contents are consistent with Example 1.

[0086] Embodiment 11

[0087] The difference from Example 1 is that the flow rate of O2 filling is adjusted to 0 L·min -1 , that is, exposed to air for reaction, and the rest of the contents are consistent with Example 1.

[0088] Example 12

[0089] The difference from Example 1 is that the flow rate of O2 filling is adjusted to 0.4 L min -1 , the rest of the content is consistent with Example 1.

[0090] Example 13

[0091] The difference from Example 1 is that the flow rate of O2 filling is adjusted to 0.8 L min -1 , the rest of the content is consistent with Example 1.

[0092] Embodiment 14

[0093] The difference from Example 1 is that the flow rate of O2 filling is adjusted to 2.4 L min -1 , the rest of the content is consistent with Example 1.

[0094] Embodiment 15

[0095] The difference from Example 1 is that Ca(OH)2 is used instead of NaOH as the base, and the rest of the contents are consistent with Example 1.

[0096] Performance Testing

[0097] The concentrations of As(T) and As(III) were analyzed by hydride generation-atomic fluorescence spectrophotometer (AFS-2202E, Haiguang, China); the concentrations of Fe(T) and Mn(T) were quantified by flame atomic absorption spectrophotometer; the concentration of Fe(II) was determined by UV-visible spectrophotometer (UV-2550, Shimadzu, Japan) using the iron-zinc method at a wavelength of 510 nm. The required amount of NaF was added to the sample to mask the interference of Fe(III); a Quanta 250 scanning electron microscope coupled with an energy dispersive spectrometer microprobe (SEM-EDS; FEI, USA) was used for solid morphology and Fe / As molar ratio; a D / max 2000PC X-ray diffractometer (XRD; Rigaku, Japan) was used with CuKa 1 radiation ( The powder X-ray diffraction patterns were recorded to identify the solid phase using a Nicolet 6700 Fourier transform infrared spectrometer (FTIR; Thermo Fisher Scientific, USA) at 400–4000 cm -1 Wavelength range: 4cm -1 The functional groups of the solids were distinguished by high resolution; KBr / sample slices were prepared by mixing 0.5% of finely ground sample in KBr. The chemical state and possible forms of As, Fe and Mn in the solid products were identified by K-Alpha+X-ray photoelectron spectroscopy (XPS; Thermo Fisher Scientific, USA) using Al Ka ​​X-rays as the radiation source; the solid products were subjected to toxic leaching according to GB5085.3-2007 (Solid Waste Identification Standard - Leaching Toxicity Identification).

[0098] Figure 2 Schematic diagram of the effect of different treatment conditions on As removal rate of acidic arsenic-containing wastewater; Figure 2It can be seen that the removal efficiency and equilibrium time of arsenic are strongly controlled by pH. According to Examples 2 to 4, the removal efficiency of arsenic shows an immediate increase as the pH increases from 5 to 7, and almost reaches equilibrium within 2 hours. However, according to Examples 1 and 5, the removal rate of As increases from pH 8 to 9 and shows a rapid rise to a maximum value (99.9% and 99.7%) within 0.25 hours, and then gradually decreases to 99.4% and 92.6%. After 8 hours of reaction, as the pH increased from 5 to 9, the removal rate of As decreased from 100% to 92.6%. The removal rate of arsenic is less affected by temperature, oxygen flow rate and neutralizer. Within 0.25 hours, almost all As was removed from the aqueous phase, and the removal rate reached 99.1-100% at the end of the experiment. At pH 5-8, temperature 25-95°C, and oxygen flow rate of 1.6L·min -1 Under the conditions of , the removal rate of arsenic can reach more than 99.4% within 8 hours.

[0099] Figure 3 Schematic diagram of the effect of different treatment conditions on the final solid TCLP test results of acidic arsenic-containing wastewater; 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 ), the leaching concentration of As(T) under the conditions of other embodiments was lower than the standard limit of arsenic 5 mg·L -1 This demonstrates that short-term storage of high-As solid precipitates in the environment results in low As leaching. In contrast, As leaching concentrations in the final solids of As(III)-rich AMD without Mn(II) and high-As(III) acidic effluents with high Fe(III) addition ranged from 23 to 837 mg·L -1 , far exceeding the standard TCLP test limit. The results show that the presence of Mn(II) significantly improves the stability of As leaching in the arsenic removal treatment product.

[0100] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as 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 and Fenton-like reaction, characterized in that: The following steps are involved: The electrolytic manganese slag and the acidic arsenic-containing wastewater are mixed to obtain the wastewater to be treated containing As(III)-Mn(II); the acidic arsenic-containing wastewater includes As 3+ and Fe 2+ ; The pH value of the wastewater containing As(III)-Mn(II) to be treated is adjusted to 3.0-11.0, oxygen-containing gas is introduced, and a Fenton-like reaction is carried out to obtain a reaction system; The reaction system is subjected to solid-liquid separation to obtain arsenic removal wastewater and arsenic stabilization products.

2. The method according to claim 1, characterized in that The pH value of the acidic arsenic-containing wastewater is less than 0.5; The content of arsenic in the acidic arsenic-containing wastewater is 0.35-12.15 g·L -1 .

3. The method according to claim 1 or 2, characterized in that: The molar ratio of As element to Mn element in the wastewater to be treated containing As(III)-Mn(II) is 1-100:1, and the molar ratio of Fe element to As element is 2-110:

1.

4. The method according to claim 3, characterized in that The concentration of As element in the wastewater to be treated containing As(III)-Mn(II) is 0.15-26 g·L -1 , the concentration of Mn element is 0.1~9g·L -1 , the concentration of Fe element is 1.6~45g·L -1 .

5. The method according to claim 1, characterized in that 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 .

6. The method according to claim 1, characterized in that The temperature of the Fenton-like reaction is 25-95°C.

7. The method according to claim 1 or 6, characterized in that: The time of the Fenton-like reaction is 0.05 to 12 hours.

8. The method according to claim 1 or 6, characterized in that: The Fenton-like reaction is carried out under stirring conditions, and the stirring speed is 200-250 r / min.

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

10. The method according to claim 1, characterized in that The content of arsenic in the arsenic removal wastewater is less than 0.49 mg / L.

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