Method for removing ethyl xanthate and arsenic in water body by sulfur chemical fiber iron ore

Abstract

The invention relates to a method for removing ethyl xanthate and arsenic in a water body through sulfur chemical fiber iron ore, and belongs to the technical field of environmental pollution treatment. According to the method, the S / Fe molar ratio of sulfur chemical fiber iron ore is regulated and controlled, and reactive oxygen species (ROS) generation and electron transfer mechanisms are combined, so that efficient degradation of ethyl xanthate and fixation of arsenic are realized. The preparation method of the sulfur chemical fiber iron ore comprises the steps of synthesis of lepidocrocite, vulcanization reaction, post-treatment and the like. When pollutants are removed, the sulfur chemical fiber iron ore is dispersed in an aqueous solution containing ethyl xanthate and / or arsenic, and the pollutants are removed through active oxygen oxidation, electrochemical oxidation, adsorption and coprecipitation, surface oxidation and other ways. The method has the advantages of environment friendliness, resource utilization, low cost, high adaptability and the like, and is suitable for treating mine wastewater, beneficiation wastewater and arsenic-polluted water.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollution control technology, and specifically relates to a method for efficiently removing ethyl xanthate and arsenic from water bodies using sulfide ferroore materials under aerobic conditions. Background Technology

[0002] Ethyl xanthate (potassium ethyl xanthate (PEX)) is a typical flotation reagent. It is easy to decompose in water to produce toxic byproducts such as carbon disulfide (CS2). Its high biotoxicity and environmental persistence can disrupt the ecological balance. Arsenic (As), as a strong carcinogenic metalloid, can harm human health through bioaccumulation.

[0003] Currently, there are still significant limitations in the treatment technologies for xanthate and arsenic. For xanthate treatment, existing methods mainly rely on biodegradation or chemical oxidation. However, due to the poor stability of xanthate in the natural environment and its complex degradation pathways, conventional treatment technologies are prone to generating secondary pollution (such as intermediate products like xanthate), making complete removal difficult (Yuan J, Li S, Ding Z, Li J, Yu A, Wen S, Bai S. Treatment Technology and Research Progress of Residual Xanthate in Mineral Processing Wastewater. Minerals. 2023; 13(3):435.). For arsenic treatment, although adsorption and precipitation methods have been widely used, their effectiveness is limited by the stability of iron-based materials. Especially in dynamic redox environments, phase transitions of iron minerals (such as reduction dissolution and sulfidation) significantly affect the arsenic fixation efficiency (Liao Jialong, Zhang Zheqiu, Chen Lijie, et al. Research progress in arsenic-containing wastewater treatment [J]. Nonferrous Metals Science and Engineering, 2018, 9(01):86-91.).

[0004] Furthermore, existing research often focuses on the removal of single pollutants, neglecting the synergistic effect mechanism of iron mineral sulfide products on organic / inorganic pollutants under alternating redox conditions, resulting in a lack of specificity and adaptability in practical treatment strategies.

[0005] Traditional treatment methods are inefficient at removing these two types of pollutants and are difficult to adapt to the fluctuating redox conditions in mining areas.

[0006] There is an urgent need to develop efficient and stable pollution control technologies. Summary of the Invention

[0007] In order to overcome the shortcomings and deficiencies of the prior art, the present invention aims to provide a method for removing ethyl xanthate and arsenic from water using sulfide ferrophosphate.

[0008] Iron (hydrogen) oxides (such as ferrihydrite) are key carriers of pollutants in the natural environment. Their sulfidation behavior can regulate the migration and transformation of pollutants by changing the mineral phase composition (such as generating magnetite, pyrite, etc.) and surface properties (such as specific surface area and isoelectric point).

[0009] Sulfide iron ore is a multiphase composite material; by adjusting the sulfur content through the sulfur-iron molar ratio, it combines high specific surface area, active oxygen generation capacity and high pollutant removal performance, as well as excellent stability and low metal leaching.

[0010] This invention provides a method for removing ethyl xanthate and arsenic from water using ferrisulfide. By adjusting the S / Fe molar ratio of ferrisulfide, its phase composition and surface chemical properties are optimized, and active oxygen species generated under aerobic conditions are utilized (…). 1 The process involves the use of O2, H2O2, etc., and electron transfer to achieve efficient degradation of PEX and fixation of As.

[0011] The objective of this invention is achieved through the following solution:

[0012] This invention provides a method for removing ethyl xanthate and arsenic from water using ferrosulfide ore, comprising the following steps:

[0013] A certain S / Fe molar ratio of ferrosulfide is dispersed in water containing ethyl xanthate (PEX) and / or arsenic (As) to form a mixed reaction system. The system is stirred and kept in contact with the atmosphere to achieve the removal of ethyl xanthate and arsenic.

[0014] Furthermore, sulfide S 2- With iron (Fe) in ferrimagnesia 3+ The molar ratio ranges from 0.1 to 1.

[0015] Furthermore, S 2- with Fe 3+ The molar ratio is 0.5.

[0016] Furthermore, sulfide ferroore remains highly efficient in water bodies with a pH range of 3.0 to 8.0.

[0017] Furthermore, after the reaction system is complete, the reaction products can be processed in the following ways:

[0018] Centrifugation separates the solid and liquid phases, and the supernatant is discharged after meeting the standards or undergoes further treatment;

[0019] After freeze-drying, the solid phase can be recycled in the following ways:

[0020] Extraction of Shuanghuangyao: Shuanghuangyao in the solid phase was extracted with n-hexane, and the solvent was evaporated for recovery;

[0021] Arsenic stabilization: Arsenic-containing solid phases can be safely landfilled after solidification treatment (such as cement solidification).

[0022] Furthermore, the preparation of sulfide ferroore includes the following steps:

[0023] S1. In the presence of a solvent, ferrihydrite is added to obtain a ferrihydrite suspension with a concentration of 0.5 g / L to 4.0 g / L;

[0024] S2. In the presence of a solvent, different amounts of Na2S·9H2O were added to the ferrihydrite suspension, and the molar ratio of sulfide to iron in ferrihydrite (S / Fe) was controlled to be 0.1–1.0. The mixture was stirred to obtain a uniform suspension. The pH was adjusted to 6.0±0.2, and the sulfidation reaction was carried out for 24–72 hours to obtain a sulfided ferrihydrite suspension.

[0025] S3. Centrifuge the sulfide ferroore suspension at 6000-8000 r / min for 5-20 min and wash with deionized water; freeze-dry the resulting precipitate and pass it through a 100-400 mesh sieve to obtain the sulfide ferroore.

[0026] Furthermore, in step S1, the concentration of the ferrihydrite suspension is 2.0 g / L.

[0027] Furthermore, in step S2, the vulcanization reaction lasts for 48 hours.

[0028] Furthermore, in step S2, S 2- with Fe 3+ The molar ratio is 0.5.

[0029] Furthermore, in step S2, the pH is adjusted using HCl or 0.5–1.0 M NaOH solution with an error of ±0.2.

[0030] Furthermore, in step S2, the pH is adjusted using a 0.75M NaOH solution.

[0031] Furthermore, in step S3, the centrifugation time is 10 minutes; and the sample is passed through a 200-mesh sieve.

[0032] Furthermore, in steps S1 and S2, the solvent is deionized water containing 0.5–1.0 M NaCl.

[0033] Furthermore, in steps S1 and S2, the solvent is deionized water containing 0.75M NaCl.

[0034] Furthermore, deionized water needs to be pre-aerated with N2 for 15 minutes to remove oxygen (oxygen content <0.1ppm).

[0035] Furthermore, the preparation of lepidocrocite includes the following steps: in the presence of a solvent, 0.05M FeCl2·4H2O is added, and the mixture is stirred at a constant temperature of 25°C to dissolve it. The pH is kept stable at 6.7, and an aeration stone is added to promote air passage, resulting in a uniform suspension. The supernatant is removed and the mixture is freeze-dried to obtain lepidocrocite.

[0036] Furthermore, the solvent is deionized water containing 0.5–1.0 M NaCl.

[0037] Furthermore, the pH was adjusted using 1M NaOH. Air was introduced while 1M NaOH was continuously added dropwise to maintain a constant pH. When the pH value remained unchanged without the addition of additional NaOH, the synthesis process was considered complete.

[0038] Furthermore, the preparation of the above-mentioned sulfide ferrisite and ferrisite, except for aeration, centrifugation, and freeze-drying operations, is all completed in an anaerobic chamber.

[0039] Furthermore, sulfide ferrophosphate degrades PEX through the following pathways:

[0040] Reactive oxygen species (ROS) oxidation: Oxidation of ferrisulfide to form 1 O2, H2O2, and other ROS degrade PEX into intermediate products such as ethyl perxanthate and S2O3H2, and finally mineralize it into CO2 and SO4. 2- ;

[0041] Electrochemical oxidation: PEX is used to generate biflavonoids (C6H) via electrochemical oxidation. 10 O2S4) is adsorbed on the surface of the solid phase.

[0042] Sulfide ferroore fixes As(III) in the following ways:

[0043] Adsorption and coprecipitation: As(III) forms Fe-As complexes or arsenic sulfides with iron oxides / sulfides;

[0044] Surface oxidation: Adsorbed As(III) is oxidized to As(V) on the mineral surface, further enhancing the fixation effect.

[0045] Furthermore, the phase composition of sulfide ferrisite includes ferrisite, goethite, magnetite, pyrite, and sulfide, etc., and its specific surface area and surface charge decrease with the increase of S / Fe molar ratio.

[0046] Furthermore, the method provided by this invention is applicable to the treatment of mine wastewater, mineral processing wastewater, and arsenic-polluted water bodies.

[0047] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0048] The method disclosed in this invention achieves efficient removal of PEX and As using ferrous sulfate ore, combining the advantages of environmental friendliness and resource utilization.

[0049] Utilizing the inherent redox properties of minerals eliminates the need for external oxidants and avoids secondary pollution;

[0050] It maintains high efficiency over a wide pH range of 3.0 to 8.0, and is particularly suitable for acidic wastewater from mining areas;

[0051] The degradation product, Shuanghuang pills, can be recycled and reused, and the arsenic-containing solid phase can be stabilized and disposed of.

[0052] The preparation process of sulfurized iron ore is simple and the cost is significantly lower than that of traditional adsorbents / catalysts, combining economic benefits with environmental sustainability. Attached Figure Description

[0053] Figure 1 The XRD patterns (a) and FTIR spectra (b) of ferrimagnesia and ferrisulfide ferrimagnesia prepared in Example 1 of the present invention are shown.

[0054] Figure 2 S2p XPS spectra of raw ferrihydrite (a) and sulfide ferrihydrite (bd) prepared in Example 1 of the present invention; S component ratio (e) based on XPS fitting results.

[0055] Figure 3 SEM analysis of raw ferrihydrite (a) and sulfide ferrihydrite (bd) prepared in Example 1 of the present invention.

[0056] Figure 4 TEM images of raw ferrihydrite (ac) and ferrihydrite sulfide (dl) prepared for Example 1 of the present invention.

[0057] Figure 5 The Zeta potential (a) and BET specific surface area (b) of raw ferrihydrite and sulfide ferrihydrite were prepared for Example 1 of the present invention.

[0058] Figure 6 The graph shows the effects of ethyl xanthate under different S / Fe molar ratios and treatment times in Comparative Examples 1, Examples 2-5.

[0059] Figure 7 The graph shows the total arsenic removal effect under different S / Fe molar ratios and treatment times for Comparative Examples 2, 6-10.

[0060] Figure 8 Flowchart of a method for removing ethyl xanthate and arsenic from water bodies using sulfide ferroore. Detailed Implementation

[0061] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0062] Unless otherwise specified, all reagents used in the examples are commercially available.

[0063] The pH of most water bodies in the environment is neutral. In the embodiments of this invention, a pH value of 6 is selected to simulate this environmental condition. In order to reduce the oxidation of sulfides during the sulfidation of ferrimagnesia, all reaction solutions are prepared using deionized water aerated with N2.

[0064] Example 1

[0065] Ferolithosite was synthesized using a room-temperature aerated ferrous oxidation-hydrolysis-precipitation chemical method, with the following steps:

[0066] After aerating the solution with N2 for 15 minutes in 1L of deionized water containing 0.75M NaCl, add 0.05M FeCl2·4H2O (i.e., 9.95g) to the solution. Place the reaction vessel in a 25℃ constant temperature water bath with a magnetic stirrer and stir the solution thoroughly until FeCl2·4H2O is completely dissolved.

[0067] The pH of the solution was adjusted to 6.7 using 1M NaOH, and then an aeration stone was added to promote air circulation. At the same time, 1M NaOH was continuously added dropwise to maintain a constant pH. When the pH value remained unchanged without the addition of additional NaOH, the synthesis process was complete.

[0068] After the reaction is complete, let the suspension stand for 6 hours, then remove the supernatant. The remaining suspension is washed six times with deionized water to remove soluble salts.

[0069] The obtained solid was freeze-dried and then passed through a 200-mesh sieve for later use.

[0070] The synthesis of ferrosulfide ore involves the following steps:

[0071] Adding 1g of ferrihydrite to 500ml of deionized water containing 0.75M NaCl yields 500mL of a 2.0g / L ferrihydrite suspension.

[0072] Using deionized water containing 0.75 M NaCl as the background electrolyte solution, different amounts of Na₂S·9H₂O were added to the ferrihydrite suspension to achieve theoretical S / Fe molar ratios of 0.1, 0.5, and 1. The initial pH of the resulting suspensions was adjusted to 6.0 ± 0.2 using HCl or NaOH solution.

[0073] After 48 hours of sulfidation, the solid product was collected by centrifugation (8000 r / min, 10 minutes) and washed with deionized water after N2 aeration, with the volume ratio of washing liquid to precipitate ≥3:1 each time.

[0074] The obtained solid was freeze-dried (pre-frozen at -60℃ for 24 hours, then freeze-dried at -80℃ for 48 hours) and passed through a 200-mesh sieve;

[0075] Except for aeration, centrifugation, and freeze-drying, all other steps are completed in an anaerobic chamber.

[0076] XRD was used to characterize ferrihydrite and ferrihydrite sulfide.

[0077] like Figure 1 As shown in Figure a, the characteristic peak positions of the synthesized lepidocrocite (S / Fe = 0) are consistent with those of the standard PDF card (PDF#97-010-8876), indicating that the prepared sample is lepidocrocite and does not contain other mineral phases. When the S / Fe molar ratio is 0.5 and 1, the main diffraction peaks of the lepidocrocite crystal plane still exist, but the intensity of the diffraction peaks weakens with increasing S / Fe molar ratio. Functional group information of the original lepidocrocite and sulfide lepidocrocite was obtained by FTIR. Figure 1 As shown in b, when the S / Fe molar ratio is 0.1, the infrared characteristic peak of ferrihydrite disappears; when the S / Fe molar ratio is 0.5, the characteristic peak of ferrihydrite is significantly weakened; when the S / Fe molar ratio is 1, no characteristic peaks related to ferrihydrite are detected.

[0078] The surface composition of ferrihydrite and ferrihydrite sulfide was further investigated using XPS spectroscopy:

[0079] like Figure 2 As shown, analysis of the Fe 2p XPS spectrum revealed that no sulfur was detected on the surface of ferrihydrite. However, on the surface of sulfided ferrihydrite, the sulfur content increased with the increase of the S / Fe molar ratio, indicating that ferrihydrite underwent successful sulfidation.

[0080] Morphological characteristics of lepidocrocite and its sulfide products observed using SEM:

[0081] like Figure 3 As shown, the synthesized lepidocrocite exhibits a rod-shaped morphology. Sulfidation significantly alters the morphology of the lepidocrocite.

[0082] like Figure 4 As shown, TEM testing was used to further observe the morphological characteristics and microstructure of ferrihydrite and sulfide ferrihydrite.

[0083] Zeta potential analysis was performed on ferrimagnesia and ferrimagnesia sulfide:

[0084] like Figure 5As shown in figure a, this study investigates the surface charge of ferrimagnesia under different pH conditions. Surface charge affects the dispersibility and adsorption properties of the particles in solution. Figure 5 As shown in b, lepidocrocite itself has a high specific surface area (347.65 m²). 2 The S / Fe molar ratio (S / Fe) gives it a potential advantage in adsorption. The effect of sulfidation on its adsorption performance can be evaluated by testing the specific surface area of ​​ferrimagnesia before and after sulfidation. Experimental results show that the specific surface area of ​​ferrimagnesia gradually decreases with increasing S / Fe molar ratio after sulfidation, which may be due to the reduction, dissolution, and agglomeration of ferrimagnesia caused by sulfidation.

[0085] The embodiments of the present invention simulate the removal of ethyl xanthate and arsenic from water using ferrosulfide ore as follows:

[0086] Ferrous sulfide is dispersed in an aqueous solution containing ethyl xanthate (PEX) and / or arsenic (As) to form a mixed reaction system;

[0087] The solution pH was adjusted to 3.0–8.0, and MES buffer was used to maintain pH stability. The pH of most water bodies in the environment is neutral. In the embodiments of this invention, a pH value of 6 was selected to simulate this environmental condition, so the solution pH was adjusted to 6.0.

[0088] The mixture was placed in the dark and magnetically stirred at room temperature (25±2℃) at a speed of 400-500 r / min for 2-6 hours. During the reaction, the system was kept in contact with the atmosphere to ensure a continuous supply of oxygen.

[0089] The concentration of PEX in the mixed reaction system is 10-100 mg / L, and the concentration of As(III) is 5-30 mg / L; in the embodiments of the present invention, the concentration of PEX is 50 mg / L and the concentration of As(III) is 15 mg / L.

[0090] The dosage of sulfide iron ore is 0.1-0.4 g / L; in the embodiments of the present invention, the dosage of sulfide iron ore is 0.2 g / L.

[0091] Comparative Example 1

[0092] 40 mg of raw fibrous iron ore was dispersed in 200 mL of 50 mg / L PEX solution with a pH of 6.0. The initial ionic strength of the suspension was adjusted using 0.1 M NaCl solution, and the pH of the system was maintained at 6.0 using 20 mM MES buffer solution.

[0093] Methanol (MeOH), superoxide dismutase (SOD), catalase (CAT), and L-histidine were added to the above solution to achieve final concentrations of 200 mM, 60 U / mL, 60 mg / L, and 100 mM, respectively.

[0094] 40 mg of raw fibrous iron oxide was added to initiate the reaction. All experiments were conducted in 250 mL brown glass bottles to prevent possible photochemical reactions and were magnetically stirred at room temperature.

[0095] Under aerobic and light-protected conditions, the original fibrous ore had almost no removal effect on PEX, and the removal rate of PEX after 10 hours of reaction was similar to the spontaneous degradation rate.

[0096] Example 2

[0097] The other steps were the same as in Comparative Example 1, except that 40 mg of ferrisulfide ore with a S / Fe molar ratio of 0.1 was used instead of the original ferrisulfide ore. After 10 hours of reaction, the PEX removal efficiency of ferrisulfide ore was calculated to be 60.9%.

[0098] Example 3

[0099] The other steps were the same as in Comparative Example 1, except that 40 mg of ferrisulfide ore with a S / Fe molar ratio of 0.5 was used instead of the original ferrisulfide ore. After 2 hours of reaction, the removal rate of PEX by ferrisulfide ore was calculated to be 98.1%.

[0100] Example 4

[0101] The other steps were the same as in Comparative Example 1, except that 40 mg of ferrisulfide ore with a S / Fe molar ratio of 1 was used instead of the original ferrisulfide ore. After 2 hours of reaction, the PEX removal rate of ferrisulfide ore was calculated to be 54.4%.

[0102] Example 5

[0103] The other steps were the same as in Comparative Example 1, except that 40 mg of ferrisulfide ore with a S / Fe molar ratio of 1 was used to replace the original ferrisulfide ore, and the reaction time was extended to 6 hours. After 6 hours of reaction, the removal rate of PEX by ferrisulfide ore was calculated to be 99.3%.

[0104] Samples from Comparative Example 1 and Examples 2-5 were collected at 5, 10, 20, 30, 45, 60, 120, 180, 240, 360 and 600 min to quantify changes in PEX and Fe(II) concentrations during the oxidation experiments.

[0105] PEX concentration determination: Take 0.5 mL of the sample to be tested into a 10 mL colorimetric tube, dilute to the mark with deionized water, and measure the PEX concentration at a wavelength of 301 nm using a UV-Vis spectrophotometer.

[0106] H₂O₂ concentration determination: Immediately add 200 μL of 2,2-bipyridine (BPY) (30 mM, dissolved in 1.0 mM HClO₄) and 100 μL of Na₂EDTA (0.1 M) sequentially to 2 mL of filtrate to complex Fe. 2+ and Fe 3+ Then, add 400 μL of phosphate buffer (0.5 M, pH 6.0). After 1 min, add 20 μL of N,N-diethyl-p-phenylenediamine (DPD) (1%, dissolved in 0.1 M H2SO4) and 10 μL of horseradish peroxidase solution (83-100 U / mL). Finally, let the solution stand for 1 min to develop color, and use a UV-Vis spectrophotometer to measure the absorbance at 551 nm to quantify the H2O2 concentration.

[0107] The results of Comparative Example 1 and Examples 2-5 combined Figure 6 It can be known that:

[0108] like Figure 6 a and Figure 6 As shown in b, after 10 hours of reaction under aerobic and light-protected conditions, the spontaneous degradation rate of PEX was 12.7%. Raw ferrimagnesia showed almost no removal effect on PEX; the PEX removal rate in the system was essentially equal to the PEX self-degradation rate. As the S / Fe molar ratio increased from 0.1 to 1, the removal rate of PEX by ferrimagnesia sulfide showed a trend of first increasing and then decreasing. At an S / Fe molar ratio of 0.1, the removal efficiency of PEX by ferrimagnesia sulfide after 10 hours of reaction was 60.9%.

[0109] Combination Figure 6 c indicates that under the optimal S / Fe molar ratio (0.5), the amount of H2O2 generated in the reaction system is significantly higher than that in other groups, further confirming the mechanism by which sulfide ferroore improves the degradation efficiency of PEX by promoting the generation of H2O2.

[0110] Comparative Example 2

[0111] 40 mg of raw fibrous iron ore was dispersed in 200 mL of 15 mg / L As(III) solution. The initial ionic strength of the suspension was adjusted using 0.1 M NaCl solution, and the pH of the system was maintained at 6.0 using 20 mM MES buffer solution.

[0112] The mouth of the glass bottle was wrapped with aluminum foil, with only a few small holes made at the top to allow the solution to circulate with the atmosphere. All experiments were conducted in 250 mL brown glass bottles with magnetic stirring at room temperature.

[0113] Under aerobic and light-protected conditions, the original fibrous ore showed a certain degree of adsorption capacity for As, and after 10 hours of reaction, 21.6% of the total As was removed.

[0114] Example 6

[0115] The other steps were the same as in Comparative Example 2, except that the S / Fe molar ratio was 0.1. After 10 hours of reaction, the total As removal rate of sulfide ferroore was calculated to be 25.7%.

[0116] Example 7

[0117] The other steps were the same as in Comparative Example 2, except that the S / Fe molar ratio was 0.5. After 10 hours of reaction, the total As removal rate of sulfide ferroore was calculated to be 39.4%.

[0118] Example 8

[0119] The other steps were the same as in Comparative Example 2, except that the S / Fe molar ratio was 1. After 2 hours of reaction, the total As removal rate of sulfide ferroore was calculated to be 51.8%.

[0120] Example 9

[0121] The other steps were the same as in Comparative Example 2, except that the S / Fe molar ratio was 1. After 6 hours of reaction, the total As removal rate of sulfide ferroore was calculated to be 78.6%.

[0122] Example 10

[0123] The other steps are the same as those in Comparative Example 2, except that the S / Fe molar ratio is 1. After 10 hours of reaction, the total As removal rate of sulfide ferroore was calculated to be 89.2%.

[0124] Samples from Comparative Example 2 and Examples 6-10 were collected at 5, 10, 20, 30, 45, 60, 120, 180, 240, 360, and 600 min and filtered through a 0.22 μm polyethersulfone aqueous filter membrane for quantification of As (As(III), As(V), and total As) during the reaction.

[0125] The results of Comparative Example 2 and Examples 6-10 show that the removal efficiency of As by sulfide ferrisulfide ore significantly improves with increasing S / Fe molar ratio and reaction time. When the S / Fe molar ratio is 1 and the reaction time is 10 h, the total As removal rate reaches 89.2%, far exceeding the adsorption and removal efficiency of the original ferrisulfide ore (21.6%). This result, combined with As speciation analysis data (…), further demonstrates the effectiveness of sulfide ore in removing As. Figure 7 This indicates that sulfide ferroore not only removes As through adsorption, but more importantly, it converts As(III) into As(V) through oxidation, forming a more stable precipitate, thereby achieving efficient removal and immobilization.

[0126] The reaction products after the reaction is complete are handled as follows:

[0127] Centrifugation separates the solid and liquid phases; the supernatant is discharged after meeting emission standards or undergoes further treatment to meet emission standards; the solid phase is freeze-dried and can be recovered and reused through Shuanghuangyao extraction and arsenic stabilization.

[0128] Extraction of Shuanghuangyao: Shuanghuangyao in the solid phase is extracted with n-hexane, and the solvent is evaporated for recovery; Arsenic stabilization: The arsenic-containing solid phase can be safely landfilled after solidification treatment.

[0129] Example 11:

[0130] This embodiment is used to verify the feasibility of the lower limit (0.5 g / L) of the concentration range of the ferrihydrite suspension described in step S1 of claim 4. Except for the following modifications, the remaining steps are the same as the synthesis method of sulfided ferrihydrite in Example 1: 0.25 g of ferrihydrite is added to 500 mL of deionized water containing 0.75 M NaCl to obtain a ferrihydrite suspension with a concentration of 0.5 g / L. Na2S·9H2O is added to the above suspension, the S / Fe molar ratio is controlled at 0.5, the pH is adjusted to 6.0 ± 0.2, and a sulfidation reaction is carried out for 48 hours.

[0131] Characterization of the obtained ferrosulfide powder showed that its phase composition was similar to that of the material with S / Fe = 0.5 in Example 1. Its application in PEX and As removal experiments (using the same methods as in Examples 3 and 7) showed that it achieved a PEX removal rate of over 95% after 2 hours and an As removal rate of over 35% after 10 hours, confirming that ferrosulfide powder prepared even at low suspension concentrations still possesses highly efficient pollutant removal capabilities.

[0132] Example 12:

[0133] This embodiment is used to verify the feasibility of the upper limit (4.0 g / L) of the concentration range of the ferrihydrite suspension described in step S1 of claim 4. Except for the following modifications, the remaining steps are the same as in Example 1: 2.0 g of ferrihydrite is added to 500 mL of deionized water containing 0.75 M NaCl to obtain a ferrihydrite suspension with a concentration of 4.0 g / L. Na2S·9H2O is added to the above suspension, the S / Fe molar ratio is controlled at 0.5, the pH is adjusted to 6.0 ± 0.2, and a sulfidation reaction is carried out for 48 hours.

[0134] The viscosity of the high-concentration suspension increased after the sulfidation reaction, but sulfided ferrimagnesia powder could still be successfully obtained through subsequent processing. This material performed well in pollutant removal experiments, proving that the upper limit of this concentration is feasible.

[0135] Example 13:

[0136] This embodiment is used to verify the feasibility of the lower limit (24 hours) of the vulcanization reaction time range described in step S2 of claim 4. Except for the following modification, the remaining steps are the same as in Example 1 (S / Fe = 0.5): the vulcanization reaction time is shortened to 24 hours.

[0137] Pollutant removal experiments showed that the material achieved a PEX removal rate of approximately 90% after 2 hours. Although this was slightly lower than that of the sample treated with 48 hours of sulfidation, it was still far higher than that of the original fibrous ore, confirming that a 24-hour sulfidation time was sufficient to form an active and effective material.

[0138] Example 14:

[0139] This embodiment is used to verify the feasibility of the upper limit (72 hours) of the vulcanization reaction time range described in step S2 of claim 4. Except for the following modification, the remaining steps are the same as in Example 1 (S / Fe = 0.5): the vulcanization reaction time is extended to 72 hours.

[0140] Extending the sulfidation time further improves the crystallinity of the minerals. This material exhibits particularly outstanding arsenic fixation effects, with a significantly higher removal rate after 10 hours compared to the 48-hour sample, indicating that a longer reaction time is beneficial for forming more stable arsenic fixation sites.

[0141] Example 15:

[0142] This embodiment is used to verify the feasibility of the lower limit of the centrifugation speed and time range (6000 r / min, 5 minutes) described in step S3 of claim 4. Except for the following modification, the remaining steps are the same as in Example 1: the sulfide ferroore suspension is centrifuged at 6000 r / min for 5 minutes.

[0143] The solid-liquid separation was good after centrifugation, and the supernatant was clear. After washing and drying, the contaminant removal performance of the obtained solid was not significantly different from that of the sample centrifuged at 8000 r / min for 10 minutes, proving that this lower limit parameter can be used for effective product separation.

[0144] Example 16:

[0145] This embodiment is used to verify the feasibility of the upper limit of centrifugation parameters (8000 r / min, 20 minutes) and the range of sieve mesh (100-400 mesh) described in step S3 of claim 4.

[0146] The sulfide ferroore suspension with S / Fe = 0.5 from Example 1 was centrifuged at 8000 r / min for 20 minutes. The results showed that higher speed and longer centrifugation ensured complete sedimentation of fine particles, and the yield of the product was slightly improved, but the main properties were consistent with the sample centrifuged for 10 minutes.

[0147] The freeze-dried block product was passed through 100-mesh and 400-mesh standard sieves, respectively. Passing through the 100-mesh sieve yielded a powder with a larger particle size and good flowability; passing through the 400-mesh sieve yielded a finer powder with a larger specific surface area. Both powder specifications are effective for water treatment, and the appropriate particle size can be flexibly selected based on the specific application requirements.

[0148] The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore provided by this invention has the following operation flow: Figure 8 As shown.

[0149] In summary, the method provided by this invention has the following beneficial effects:

[0150] Utilizing the inherent redox properties of minerals eliminates the need for external oxidants and avoids secondary pollution;

[0151] It maintains high efficiency over a wide pH range of 3.0 to 8.0, and is particularly suitable for acidic wastewater from mining areas;

[0152] The degradation product, Shuanghuang pills, can be recycled and reused, and the arsenic-containing solid phase can be stabilized and disposed of.

[0153] The preparation process of sulfurized iron ore is simple and the cost is significantly lower than that of traditional adsorbents / catalysts, combining economic benefits with environmental sustainability.

[0154] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for removing ethyl xanthate and arsenic from water using ferrosulfide ore, characterized in that, Includes the following steps: A certain S / Fe molar ratio of ferrosulfide is dispersed in water containing ethyl xanthate (PEX) and / or arsenic (As) to form a mixed reaction system. The system is stirred and kept in contact with the atmosphere to achieve the removal of ethyl xanthate and arsenic.

2. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, The sulfide S 2- With iron (Fe) in ferrimagnesia 3+ The molar ratio ranges from 0.1 to 1.

3. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, After the reaction is completed, the reaction products are processed as follows: Centrifugation separates the solid and liquid phases, and the supernatant is discharged after meeting the standards or undergoes further treatment; After freeze-drying, the solid phase can be recycled in the following ways: Extraction of Shuanghuangyao: Shuanghuangyao in the solid phase was extracted with n-hexane, and the solvent was evaporated for recovery; Arsenic stabilization: Arsenic-containing solid phases can be safely landfilled after solidification treatment.

4. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, The preparation of the sulfide ferroore includes the following steps: S1. In the presence of a solvent, ferrihydrite is added to obtain a ferrihydrite suspension with a concentration of 0.5 g / L to 4.0 g / L; S2. In the presence of a solvent, add Na2S·9H2O to the ferrihydrite suspension, control the molar ratio of sulfide to iron in ferrihydrite (S / Fe) to be 0.1-1.0, mix and stir, adjust the pH to 6.0±0.2, and carry out the sulfidation reaction for 24-72 hours to obtain a sulfided ferrihydrite suspension. S3. Centrifuge the sulfide ferroore suspension at 6000-8000 r / min for 5-20 min, wash with deionized water; freeze-dry the resulting precipitate and pass it through a 100-400 mesh sieve to obtain sulfide ferroore powder.

5. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 2, characterized in that, In steps S1 and S2, the solvent is deionized water containing 0.5–1.0 M NaCl; in step S2, 0.5–1.0 M NaOH is used to adjust the pH.

6. The method for removing ethyl xanthate and arsenic from water bodies using sulfide ferroore according to claims 3 and 4, wherein the deionized water needs to be pre-aerated with N2 to remove oxygen.

7. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, The pathways for the degradation of PEX by the sulfide ferroore include: reactive oxygen species (ROS) oxidation and electrochemical oxidation; the pathways for fixing As(III) include: adsorption and co-precipitation and surface oxidation.

8. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, By controlling the S / Fe molar ratio of sulfide ferrophosphate and combining it with the mechanism of reactive oxygen species (ROS) generation and electron transfer, the efficient degradation of ethyl xanthate and the fixation of arsenic are achieved.

9. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, The phase composition of the sulfide ferrisite includes one or more of ferrisite, goethite, magnetite, pyrite, and sulfide, and its specific surface area and surface charge decrease with increasing S / Fe molar ratio.

10. The method for removing ethyl xanthate and arsenic from water using ferrosulfide ore according to claim 1, characterized in that, The method is applicable to the treatment of mine wastewater, mineral processing wastewater, and arsenic-contaminated water bodies.

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