Iron-sulfur-based supported environmental remediation material, and preparation method and application thereof

Abstract

The application provides an iron-sulfur-based load-type environmental remediation material, a preparation method and application thereof. The iron-sulfur-based load-type environmental remediation material comprises a carrier and an iron-sulfur-based material dispersed on the surface and skeleton structure of the carrier. The particle size of the iron-sulfur-based material is 100-300 nm, and the specific surface area is 50-100 m 2 / g. The particle size of the iron-sulfur-based load-type environmental remediation material is 0.5-50 μm. The preparation method is simple in operation and low in production cost. The iron-sulfur-based material is directly and uniformly distributed on the surface and skeleton structure of the carrier material through a high-temperature reduction reaction, so that the aggregation of the iron-sulfur-based material is inhibited. The iron-sulfur-based load-type environmental remediation material can be used as a heavy metal and / or organic contaminated soil and groundwater permeation reaction wall remediation material, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of environmental remediation technology, and in particular to an iron-sulfur-based supported environmental remediation material, its preparation method, and its application. Background Technology

[0002] With the continuous development of industrialization and urbanization, pollutant emissions have become a serious environmental problem, posing a severe threat to human health and ecosystems. Pollutants in the atmosphere, water bodies, and soil not only affect the natural ecological balance but also pose a serious challenge to the sustainable development of human society. The environmental remediation industry has shifted from simply pursuing efficiency to emphasizing both low-carbon emission reduction and efficient remediation. Implementing green and low-carbon risk management and remediation is an urgent need for the industry's transformation and development. Developing and applying environmentally friendly risk management and remediation materials, improving their long-term effectiveness, efficiency, and safety, and promoting environmental remediation work towards a more sustainable direction are the main development requirements.

[0003] Iron-sulfur based materials, due to their combination of the advantages of single matrix materials such as iron-based and sulfur-based materials, can simultaneously provide Fe(0), Fe(II) and S(-II) as electron donors, thus exhibiting high reactivity and having a wide range of applications in soil and groundwater remediation.

[0004] CN115432828A discloses an in-situ remediation agent for chlorinated organic matter in soil and groundwater, comprising nano-micron-sized ZVI, organic carbon source, biological nutrients, and binder. The mass percentages of each component are: 30-50% nano-micron-sized ZVI, 40-60% organic carbon source, 9-20% nutrients, and 1-5% binder. In this in-situ remediation agent for chlorinated organic matter in soil and groundwater, the nano-micron-sized ZVI is a surface-treated material. The sulfide reacts with some iron on the surface of the zero-valent iron ZVI to form ferrous sulfide, which prevents the zero-valent iron ZVI from being oxidized and passivated by water. Furthermore, the ferrous sulfide can undergo a reductive dechlorination reaction with chlorinated organic matter in groundwater. The organic carbon source and nutrients can effectively control the release of the organic carbon source and the rate of its degradation by microorganisms, providing electron donors for microorganisms with reductive dechlorination capabilities for a long period, extending the effectiveness to more than two years. This reduces the frequency and dosage of the agent.

[0005] CN110302746A discloses a composite material for the remediation of hexavalent chromium-contaminated water or soil and its preparation method. The main components and their contents of the composite material are montmorillonite as the framework material, nano-ferrous sulfide as the reducing agent, and sodium carboxymethyl cellulose as a stabilizer for the nano-ferrous sulfide. The preparation method of the composite material involves pretreating a certain amount of montmorillonite, and then loading nano-ferrous sulfide onto the interlayer and surface of montmorillonite through co-precipitation under reducing conditions and the action of the stabilizer. The composite material is obtained by centrifugation or filtration. This composite material has been proven to have a high efficiency in removing hexavalent chromium.

[0006] CN116212721A discloses a method for preparing and applying a modified nano-ferrous sulfide slurry. The method involves grinding sulfur powder and ferrocene as raw materials, pressing them into tablets, vacuuming, and pyrolyzing them to prepare flake-shaped nano-ferrous sulfide. The flake-shaped nano-ferrous sulfide is then ultrasonically mixed with an anionic surfactant in water to prepare the modified ferrous sulfide slurry.

[0007] However, the aforementioned iron-sulfur based materials still suffer from problems such as easy oxidation, agglomeration, and deactivation in practical applications. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides an iron-sulfur-based supported environmental remediation material, its preparation method and application. The iron-sulfur-based supported environmental remediation material has a small particle size, and the iron-sulfur-based material is uniformly distributed on the surface and in the skeleton structure of the carrier, which avoids the agglomeration and deactivation of the iron-sulfur-based material. At the same time, the iron-sulfur-based material has a smaller particle size, a larger specific surface area, more reaction sites, and a larger adsorption capacity, and has good application prospects in the field of soil and groundwater infiltration reactive barrier remediation.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an iron-sulfur-based supported environmental remediation material, the iron-sulfur-based supported environmental remediation material comprising a carrier and an iron-sulfur-based material dispersed on the surface of the carrier and in its framework structure; the iron-sulfur-based material having a particle size of 100–300 nm and a specific surface area of ​​50–100 m². 2 / g; the particle size of the iron-sulfur-based supported environmental remediation material is 0.5-50μm.

[0011] In the iron-sulfur-based supported environmental remediation material of this invention, the iron-sulfur-based material plays a major role in the removal of heavy metals and / or organic matter. It can provide Fe(O), Fe(II), and S(-II), all of which are strong reducing substances, and can remove pollutants through adsorption, reduction, and co-precipitation. The iron-sulfur-based material in this environmental remediation material has a small particle size, a large specific surface area, and is uniformly dispersed on the carrier surface and in the framework structure. This avoids the rapid oxidation of the iron-sulfur-based material by air, increases the number of active sites, and significantly improves the removal efficiency of heavy metals and / or organic matter per unit time, showing broad application prospects.

[0012] The particle size of the iron-sulfur based material described in this invention is 100-300 nm, for example, it can be 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, 220 nm, 240 nm, 260 nm, 280 nm or 300 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] Specific surface area is 50-100 m² 2 / g, for example, could be 50m 2 / g、55m 2 / g, 60m 2 / g, 65m 2 / g, 70m 2 / g, 75m 2 / g, 80m 2 / g, 90m 2 / g, 95m 2 / g or 100m 2 / g, but not limited to the listed values, other unlisted values ​​within the range also apply.

[0014] The particle size of the iron-sulfur-based supported environmental remediation material is 0.5–50 μm, for example, it can be 0.5 μm, 0.55 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm, 10.0 μm, 11.0 μm, 20 μm, 30 μm, 40 μm, 45 μm or 50 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the carrier comprises any one or a combination of at least two of aluminosilicates, activated carbon, or chitosan, wherein typical but non-limiting combinations include a combination of aluminosilicates and activated carbon, a combination of chitosan and aluminosilicates, or a combination of activated carbon and chitosan.

[0016] The carrier described in this invention has a large specific surface area and stable chemical and mechanical properties. It can be used as a nucleation site in the synthesis of iron-sulfur-based supported environmental remediation materials to reduce the aggregation of iron-sulfur-based material particles.

[0017] Preferably, the iron-sulfur-based material comprises ferrous sulfide and / or elemental iron.

[0018] Secondly, the present invention also provides a method for preparing an iron-sulfur-based supported environmental remediation material as described in the first aspect, the method comprising the following steps:

[0019] (1) After mixing ferrous sulfate solution and carrier, solid-liquid separation and drying were performed sequentially to obtain the reduction precursor;

[0020] (2) The reduction precursor is subjected to a reduction reaction at a temperature of 400-900℃ in a reducing atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0021] The preparation method of the iron-sulfur-based supported environmental remediation material of this invention involves directly and uniformly distributing the iron-sulfur-based material onto the surface of a carrier material through a high-temperature reduction method. This direct high-temperature reduction method ensures strong and uniform contact between the iron-sulfur-based material and the carrier, increasing the specific surface area of ​​the iron-sulfur-based material. Furthermore, the carrier itself possesses a certain adsorption capacity, enhancing the reduction treatment effect. By controlling the temperature and time of the reduction reaction, iron-sulfur-based supported environmental remediation materials with different iron-sulfur contents can be obtained. The preparation method of the iron-sulfur-based supported environmental remediation material of this invention is simple, uses inexpensive raw materials, allows for controllable material composition, has low requirements for production equipment, low energy consumption, low production cost, and is easy to scale up for mass production.

[0022] The temperature of the reduction reaction described in this invention is 400 to 900°C, for example, it can be 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] If the temperature of the reduction reaction described in this invention is too low, ferrous sulfate will not be able to be reduced to obtain iron-sulfur-based materials; if the temperature of the reduction reaction is too high, the structure of the carrier will be destroyed or the composition of the carrier will change.

[0024] Preferably, the raw materials for the ferrous sulfate solution in step (1) include any one or a combination of at least two of analytical grade ferrous sulfate, industrial ferrous sulfate, or industrial ferrous sulfate waste salt, a combination of industrial ferrous sulfate waste salt and analytical grade ferrous sulfate, or a combination of industrial ferrous sulfate and industrial ferrous sulfate waste salt, preferably analytical grade ferrous sulfate.

[0025] Preferably, the concentration of the ferrous sulfate solution in step (1) is 10 to 30 wt.%, for example, it can be 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, or 30 wt.%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 20 to 30 wt.%.

[0026] The preferred concentration of the ferrous sulfate solution in this invention is 10-30 wt.%. If the concentration of the ferrous sulfate solution is too low, the amount of iron-sulfur groups in the iron-sulfur-based environmental remediation material will be low, resulting in a decrease in the pollutant removal efficiency of the iron-sulfur-based environmental remediation material. If the concentration of the ferrous sulfate solution is too high, the iron-sulfur-based material will be unevenly dispersed, leading to a waste of the ferrous sulfate solution.

[0027] Preferably, the carrier comprises any one or a combination of at least two of aluminosilicates, activated carbon, or chitosan, wherein typical but non-limiting combinations include a combination of aluminosilicates and activated carbon, a combination of chitosan and aluminosilicates, or a combination of activated carbon and chitosan.

[0028] Preferably, the liquid-solid ratio of the ferrous sulfate solution to the carrier in step (1) is (50-500):1mL / g, for example, it can be 50:1, 100:1, 200:1, 400:1, 400:1 or 500:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably (100-250):1mL / g.

[0029] In this invention, the liquid-to-solid ratio of the ferrous sulfate solution to the carrier is preferably (50-500):1 mL / g. If the liquid-to-solid ratio of the ferrous sulfate solution to the carrier is too low, the loading of iron-sulfur-based materials in the final iron-sulfur-based supported environmental remediation material will be small, resulting in reduced pollutant removal performance. If the liquid-to-solid ratio of the ferrous sulfate solution to the carrier is too high, the final iron-sulfur-based supported environmental remediation material will have higher strength, reduced porosity, and reduced loading and dispersion performance of the iron-sulfur-based materials.

[0030] Preferably, the mixing in step (1) includes any one or a combination of at least two of mechanical stirring, ultrasonic dispersion or oscillatory dispersion, wherein typical but not limited combinations include a combination of mechanical stirring and ultrasonic dispersion, a combination of oscillatory dispersion and mechanical stirring, or a combination of ultrasonic dispersion and oscillatory dispersion, preferably mechanical stirring.

[0031] Preferably, the mechanical stirring speed is 100 to 400 r / min, for example, it can be 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min or 400 r / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 200 to 300 r / min.

[0032] Preferably, the mixing time in step (1) is 24 to 120 hours, for example, it can be 24 hours, 48 ​​hours, 72 hours, 96 hours or 120 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 48 to 72 hours.

[0033] The preferred method of mixing in this invention is mechanical stirring, with a stirring speed of 100–400 r / min and a mixing time of 24–120 h. If the mechanical stirring speed is too low or the stirring time is too short, the carrier will not be able to fully impregnate with ferrous sulfate, resulting in a low loading of iron-sulfur-based materials in the final iron-sulfur-based supported environmental remediation material and weakened reducibility. If the mechanical stirring speed is too high or the stirring time is too long, additional energy consumption will be added after the carrier has reached saturation of ferrous sulfate adsorption, increasing both time and energy costs.

[0034] Preferably, the drying process in step (1) includes any one or a combination of at least two of vacuum drying, freeze drying or oven drying, wherein typical but not limited combinations include a combination of vacuum drying and freeze drying, a combination of oven drying and vacuum drying or a combination of freeze drying and oven drying, preferably freeze drying.

[0035] Preferably, before the reduction reaction in step (2), the temperature is raised to 400-900°C under a first inert atmosphere. For example, it can be 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400-500°C.

[0036] Preferably, the first inert atmosphere includes any one or a combination of at least two of nitrogen atmosphere, argon atmosphere or helium atmosphere, wherein typical but non-limiting combinations include a combination of nitrogen atmosphere and argon atmosphere, a combination of helium atmosphere and nitrogen atmosphere or a combination of argon atmosphere and helium atmosphere.

[0037] Preferably, in step (1), the first inert atmosphere is achieved by continuously introducing an inert gas.

[0038] Preferably, the flow rate of the inert gas is 5 to 800 mL / min, for example, it can be 5 mL / min, 100 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min or 800 mL / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 100 to 400 mL / min.

[0039] In this invention, an inert atmosphere is preferably introduced during the heating process to eliminate the presence of oxidizing gases. If the flow rate of the inert gas is too low, the oxidizing gases cannot be completely eliminated, and they will oxidize ferrous iron to ferric iron, thus preventing the iron-based material from having a reducing effect. If the flow rate of the inert gas is too high, it will result in waste of inert gas and increase the preparation cost of iron-sulfur-based supported environmental remediation materials.

[0040] Preferably, the reducing atmosphere in step (2) includes a hydrogen atmosphere or a carbon monoxide atmosphere, preferably a hydrogen atmosphere.

[0041] Preferably, the reducing atmosphere in step (2) is achieved by continuously introducing a reducing gas.

[0042] Preferably, the flow rate of the reducing gas in step (2) is 5 to 400 mL / min, for example, it can be 5 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min or 400 mL / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 100 to 200 mL / min.

[0043] The preferred flow rate of the reducing gas in this invention is 5-400 mL / min. If the flow rate of the reducing gas is too low, the amount of hydrogen gas introduced within the reduction time range will be too small, making it impossible to fully reduce ferrous sulfate to iron-sulfur-based materials. If the flow rate of the reducing gas is too high, it will lead to an increase in the percentage of iron content and a decrease in the percentage of sulfur content in the reduction product, affecting the application effect of the final iron-sulfur-based supported environmental remediation material, and will also cause waste of reducing gas and increase costs.

[0044] Preferably, the temperature of the reduction reaction in step (2) is 400 to 900°C, for example, it can be 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400 to 500°C.

[0045] Preferably, the reduction reaction time in step (2) is 0.5 to 5 hours, for example, it can be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.5 to 2.5 hours.

[0046] The preferred reduction reaction time of this invention is 0.5 to 5 hours. If the reduction reaction time is too short, the ferrous sulfate will be incompletely reduced, and the appropriate content of iron-sulfur-based material cannot be obtained. If the reduction reaction time is too long, the percentage of iron content in the reduction product will increase and the percentage of sulfur content will decrease, affecting the application effect of iron-sulfur-based supported environmental remediation materials.

[0047] Preferably, after the reduction reaction described in step (2), the temperature is lowered to 20-30°C in a second inert atmosphere. For example, it can be 20°C, 22°C, 24°C, 25°C, 27°C, 29°C, or 30°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] Preferably, the second inert atmosphere includes any one or a combination of at least two of nitrogen atmosphere, argon atmosphere or helium atmosphere, wherein typical but non-limiting combinations include a combination of nitrogen atmosphere and argon atmosphere, a combination of helium atmosphere and nitrogen atmosphere or a combination of argon atmosphere and helium atmosphere.

[0049] Preferably, in step (2), the second inert atmosphere is achieved by continuously introducing an inert gas.

[0050] Preferably, the flow rate of the inert gas is 5 to 800 mL / min, for example, it can be 5 mL / min, 100 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min or 800 mL / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 100 to 400 mL / min.

[0051] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0052] (1) After mixing ferrous sulfate solution and carrier at a liquid-to-solid ratio of (50-500):1 mL / g for 24-120 h, the mixture is then subjected to solid-liquid separation and drying to obtain the reduction precursor.

[0053] The raw materials for the ferrous sulfate solution include any one or a combination of at least two of analytical grade ferrous sulfate, industrial ferrous sulfate, or industrial ferrous sulfate waste salt; the concentration of the ferrous sulfate solution is 10–30 wt.%; the carrier includes any one or a combination of at least two of aluminosilicate, activated carbon, or chitosan; the mixing includes any one or a combination of at least two of mechanical stirring, ultrasonic dispersion, or oscillating dispersion; the drying process includes any one or a combination of at least two of vacuum drying, freeze drying, or oven drying.

[0054] (2) The reduction precursor is heated to 400-900°C in the first inert atmosphere and then subjected to a reduction reaction at 400-900°C for 0.5-5 hours in the reducing atmosphere. After that, it is cooled to 20-30°C in the second inert atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0055] The first inert atmosphere includes any one or a combination of at least two of nitrogen, argon, or helium atmospheres; the first inert atmosphere is achieved by continuously introducing an inert gas; the flow rate of the inert gas is 5–800 mL / min.

[0056] The reducing atmosphere includes a hydrogen atmosphere or a carbon monoxide atmosphere; the reducing atmosphere is achieved by continuously introducing a reducing gas; the flow rate of the reducing gas is 5–400 mL / min.

[0057] The second inert atmosphere includes any one or a combination of at least two of nitrogen, argon, or helium atmospheres; the second inert atmosphere is achieved by continuously introducing an inert gas; the flow rate of the inert gas is 5 to 800 mL / min.

[0058] Thirdly, the present invention also provides the use of the iron-sulfur-based loaded environmental remediation material as described in the first aspect, wherein the iron-sulfur-based loaded environmental remediation material is applied to the permeable reactive barrier of soil and groundwater contaminated with heavy metals and / or organic matter.

[0059] The iron-sulfur-based supported environmental remediation material of this invention has good stability, high specific surface area, good water resistance, high compressive strength, and a particle size of 0.5-50 μm. The supported iron-sulfur-based material has high reactivity and can adsorb and / or precipitate heavy metals and organic matter under anaerobic conditions. The carrier also has adsorption properties, further promoting the removal of pollutants. It is suitable for use in permeable reactive walls for soil and groundwater contaminated with heavy metals and / or organic matter.

[0060] Compared with the prior art, the present invention has at least the following beneficial effects:

[0061] (1) The iron-sulfur-based supported environmental remediation material provided by the present invention has a small particle size and a large specific surface area. The iron-sulfur-based material is dispersed on the surface of the carrier and in the skeleton structure, and the structure is stable.

[0062] (2) The preparation method of the iron-sulfur-based loaded environmental remediation material provided by the present invention is a one-step high-temperature reduction method to directly distribute the iron-sulfur-based material evenly on the surface of the carrier material. Compared with the existing technology, the process is simple, the production cost is low, and it is easy to scale up production.

[0063] (3) The iron-sulfur-based loaded environmental remediation material provided by the present invention can be used as an adsorbent and reducing agent for the remediation of soil and groundwater permeable reactive walls contaminated with heavy metals and / or organic matter. It can prevent the reducing material from caking and clogging during water treatment and increase the contact area between the effective reducing component iron-sulfur-based and the aqueous phase. Attached Figure Description

[0064] Figure 1 These are XRD phase diagrams of the iron-sulfur-based supported environmental remediation materials prepared in Examples 1, 9, and 12 of this invention.

[0065] Figure 2 This is a morphological image of the iron-sulfur-based supported environmental remediation material prepared in Example 1 of the present invention.

[0066] Figure 3 This is the EDS spectrum of the iron-sulfur-based supported environmental remediation material prepared in Example 1 of this invention.

[0067] Figure 4 This is a comparison chart showing the effect of iron-sulfur-based supported environmental remediation materials prepared in Examples 1, 9 and 12 of this invention in removing antimony. Detailed Implementation

[0068] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0069] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0070] Example 1

[0071] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0072] (1) A 20 wt.% ferrous sulfate solution and a carrier kaolin were mixed at a liquid-to-solid ratio of 100:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0073] (2) The reduction precursor is heated to 400°C in a nitrogen atmosphere and then subjected to a reduction reaction at 400°C for 2.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0074] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0075] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0076] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0077] Example 2

[0078] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0079] (1) A 20 wt.% ferrous sulfate solution and a carrier kaolin were mixed at a liquid-to-solid ratio of 100:2 mL / g and mechanically stirred for 50 h to form a paste. The paste was then collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0080] (2) The reduction precursor is heated to 400°C in a nitrogen atmosphere and then subjected to a reduction reaction at 400°C for 2.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0081] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0082] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0083] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0084] Example 3

[0085] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0086] (1) A 20 wt.% ferrous sulfate solution and a carrier kaolin were mixed at a liquid-to-solid ratio of 200:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was then collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0087] (2) The reduction precursor is heated to 400°C in a nitrogen atmosphere and then subjected to a reduction reaction at 400°C for 2.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in a nitrogen atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0088] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0089] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0090] The nitrogen atmosphere is achieved by continuously introducing argon gas; the flow rate of the nitrogen gas is 200 mL / min.

[0091] Example 4

[0092] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0093] (1) A 20 wt.% ferrous sulfate solution and a carrier kaolin were mixed at a liquid-to-solid ratio of 100:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0094] (2) The reduction precursor is heated to 500°C in a nitrogen atmosphere and then subjected to a reduction reaction at 500°C for 0.5 h in a hydrogen atmosphere. After that, it is cooled to 30°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0095] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0096] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0097] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0098] Example 5

[0099] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0100] (1) A ferrous sulfate solution with a concentration of 20 wt.% and a carrier mica were mixed at a liquid-to-solid ratio of 100:2 mL / g and mechanically stirred for 50 h to form a paste. The paste was then collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0101] (2) The reduction precursor is heated to 500°C in a nitrogen atmosphere and then subjected to a reduction reaction at 500°C for 0.5 h in a hydrogen atmosphere. After that, it is cooled to 22°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0102] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0103] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0104] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0105] Example 6

[0106] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0107] (1) A ferrous sulfate solution with a concentration of 20 wt.% and a carrier mica were mixed at a liquid-to-solid ratio of 200:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0108] (2) The reduction precursor is heated to 500°C in an argon atmosphere and then subjected to a reduction reaction at 500°C for 0.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0109] The argon atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the argon gas is 200 mL / min.

[0110] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0111] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0112] Example 7

[0113] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0114] (1) A ferrous sulfate solution with a concentration of 20 wt.% and a carrier activated carbon were mixed at a liquid-to-solid ratio of 200:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was then collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0115] (2) The reduction precursor is heated to 500°C in a nitrogen atmosphere and then subjected to a reduction reaction at 500°C for 0.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0116] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0117] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0118] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0119] Example 8

[0120] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material, the method comprising the following steps:

[0121] (1) A ferrous sulfate solution with a concentration of 20 wt.% and a carrier chitosan were mixed at a liquid-to-solid ratio of 200:1 mL / g and mechanically stirred for 50 h to form a paste. The paste was collected by filtration with a filter cloth. The collected solid was freeze-dried to obtain a reduction precursor. The raw material for the ferrous sulfate solution was analytical grade ferrous sulfate.

[0122] (2) The reduction precursor is heated to 500°C in a nitrogen atmosphere and then subjected to a reduction reaction at 500°C for 0.5 h in a hydrogen atmosphere. After that, it is cooled to 20°C in an argon atmosphere to obtain the iron-sulfur-based supported environmental remediation material.

[0123] The nitrogen atmosphere is achieved by continuously introducing nitrogen gas; the flow rate of the nitrogen gas is 200 mL / min.

[0124] The hydrogen atmosphere is achieved by continuously introducing hydrogen gas; the flow rate of the hydrogen gas is 100 mL / min.

[0125] The argon atmosphere is achieved by continuously introducing argon gas; the flow rate of the argon gas is 200 mL / min.

[0126] Example 9

[0127] This embodiment provides a method for preparing an environmental remediation material. The preparation method is the same as in Example 1 except that step (1) is omitted and the reducing precursor in step (2) is replaced with solid ferrous sulfate.

[0128] Example 10

[0129] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material. Except for the mechanical stirring time of 40h in step (1), the preparation method is the same as that in Example 1.

[0130] Example 11

[0131] This embodiment provides a method for preparing an iron-sulfur-based supported environmental remediation material. Except for the hydrogen flow rate of 200 mL / min in step (2), the preparation method is the same as in Example 1.

[0132] Example 12

[0133] This embodiment provides a method for preparing an environmental remediation material. The preparation method is the same as in Example 1 except that step (1) is omitted and the reduction precursor in step (2) is replaced with kaolin.

[0134] Example 13

[0135] This embodiment provides a method for preparing an environmental remediation material. The preparation method is the same as in Example 4 except that step (1) is omitted and the reduction precursor in step (2) is replaced with kaolin.

[0136] The XRD phase diagrams of the iron-sulfur-based supported environmental remediation materials prepared in Examples 1, 9, and 12 of this invention are shown below. Figure 1 As shown, from Figure 1 It can be seen that the main phase of Example 12 is kaolin, indicating that the composition of the kaolin carrier itself did not change under the conditions of Example 12; the main phase of Example 9 is FeS, indicating that iron-sulfur based materials were successfully obtained under the conditions of Example 9; the main phases of Example 1 are kaolin and FeS, indicating that iron-sulfur based supported environmental remediation materials were successfully obtained under the conditions of Example 1.

[0137] The morphology of the iron-sulfur-based supported environmental remediation material prepared in Example 1 of this invention is shown in the figure below. Figure 2 As shown, from Figure 2 It can be seen that the iron-sulfur-based particles are uniformly distributed in the lamellar structure of the kaolin carrier.

[0138] The EDS spectrum of the iron-sulfur-based supported environmental remediation material prepared in Example 1 of this invention is shown below. Figure 3 As shown, from Figure 3 It can be seen that the main elemental composition of the obtained material is Si, Al, O, Fe and S, which further proves that the carrier kaolin successfully loaded iron-sulfur-based particles and successfully prepared iron-sulfur-based loaded environmental remediation materials.

[0139] The comparison diagrams of the antimony removal effects of the iron-sulfur-based supported environmental remediation materials prepared in Examples 1, 9, and 12 of this invention are shown below. Figure 4 As shown, from Figure 4 It can be seen that in Example 12, the kaolin itself, the carrier, has a certain removal effect on antimony even without iron-sulfur-based particles; the material obtained in Example 9 only has iron-sulfur-based particles that have a good removal effect on antimony; the iron-sulfur-based loaded environmental remediation material obtained in Example 1 combines the removal effects of the carrier material and iron-sulfur-based particles on antimony, and significantly improves the reactivity of the effective iron-sulfur-based components, achieving a 1+1>2 effect.

[0140] The loading of iron and sulfur in the iron-sulfur-based supported environmental remediation materials obtained in the above embodiments was determined, as well as their removal effects on heavy metals such as arsenic and antimony and organic compounds such as dibromoethane.

[0141] The method for determining iron content is as follows: Weigh 10 mg of the composite material into a 20 mL centrifuge tube, add 10 mL of HCl, react on a shaker for 5 hours, then transfer the suspension to a 25 mL volumetric flask and dilute to the mark with deoxygenated water. Take 2 mL of the diluted suspension, filter it through a 0.22 μm filter membrane, and transfer it to a colorimetric tube using a pipette. Determine the Fe content according to HJ / T345-2007. 2+ content;

[0142] The method for determining sulfur content is as follows: the sulfur content in the composite material is determined using a carbon-sulfur analyzer;

[0143] Test method for antimony removal effect in water: Weigh 10mg of the prepared repair material and place it in a plastic bottle containing 100mL of 20mg / L Sb(III) solution. Shake at 25℃ and 200rpm for 24h. Then, determine the total antimony content before and after the reaction using inductively coupled plasma atomic emission spectrometry (ICP).

[0144] Test method for arsenic removal effect in water: Wastewater with arsenic content of 2 mg / L provided by the enterprise was collected. 100 mL of arsenic-containing wastewater was measured into a plastic bottle, and 10 mg of the prepared remediation material was added. The shaking temperature was 25℃ and the rotation speed was 200 rpm. After 24 h of reaction, the total arsenic content before and after the reaction was determined by inductively coupled plasma atomic emission spectrometry (ICP).

[0145] Test method for the removal effect of dibromoethane in soil: Soil contaminated with 100 mg / kg dibromoethane was placed in a reactor. The remediation material and contaminated soil were mixed evenly at a mass ratio of 1:10. The moisture content was adjusted to 10%. After 7 days of incubation and passivation in a ventilated outdoor area, the moisture content in the soil was measured. The change in organic matter concentration before and after the reaction was measured by gas chromatography-mass spectrometry.

[0146] The test results are shown in Table 1:

[0147] Table 1

[0148]

[0149]

[0150] As can be seen from Table 1:

[0151] (1) As can be seen from Examples 1 to 8, the preparation method of the iron-sulfur-based supported environmental remediation material provided by the present invention can obtain an iron-sulfur-based supported environmental remediation material with an iron content of 5.99 to 17.52 wt.% and a sulfur content of 1.94 to 7.77 wt.% by controlling the raw material ratio and the conditions of the reduction reaction, and has high removal efficiency for antimony, arsenic and dibromoethane.

[0152] (2) Combining Examples 1 and 9, it can be seen that in Example 9, solid ferrous sulfate was directly reduced without a carrier. Compared with Example 1, under the same material addition conditions, its iron-sulfur content was much higher than that of the material obtained in Example 1. Comparing the effective iron-sulfur component content and the removal efficiency of antimony, arsenic, and dibromoethane in Examples 1 and 9, the iron-sulfur-based supported environmental remediation material obtained in Example 1 showed better removal effect per unit of iron-sulfur-based component. This indicates that the carrier played a dispersing role on the iron-sulfur-based particles, improving their reactivity.

[0153] (3) It can be seen from the combined results of Example 1 and Example 10 that the mechanical stirring time in Example 10 is 40h, which is shorter than the 50h time in Example 1. This will result in the carrier not being able to fully impregnate ferrous sulfate, resulting in a low loading of iron-sulfur-based materials in the final iron-sulfur-based supported environmental remediation material. The iron content is only 0.73wt.% and the sulfur content is only 0.417wt.%. The reducing power of the iron-sulfur-based supported environmental remediation material is weakened, and the removal efficiency of antimony, arsenic and dibromoethane is greatly reduced.

[0154] (4) It can be seen from the combined results of Example 1 and Example 11 that the hydrogen flow rate in Example 11 is 200 mL / min, which is higher than the 100 mL / min in Example 1. The percentage of iron content in the iron-sulfur-based supported environmental remediation material increases to 13.42 wt.%, while the percentage of sulfur content decreases to only 0.11 wt.%. The removal efficiency of the iron-sulfur-based supported environmental remediation material for antimony, arsenic and dibromoethane is greatly reduced, and hydrogen is wasted, increasing the cost.

[0155] (5) It can be seen from the combined examples 1 and 12, and examples 4 and 13 that examples 12 and 13 only use aluminosilicates as a carrier for the reduction reaction. Since there is no iron-sulfur based material to provide strong reducing substances such as Fe(0), Fe(II) and S(-II), the removal efficiency of this environmental remediation material for antimony, arsenic and dibromoethane is greatly reduced.

[0156] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing an iron-sulfur-based supported environmental remediation material, characterized in that, The preparation method includes the following steps: (1) After mixing ferrous sulfate solution and carrier, the mixture is subjected to solid-liquid separation and drying to obtain the reduction precursor; (2) The reduction precursor is subjected to a reduction reaction at a temperature of 400~900℃ in a reducing atmosphere to obtain the iron-sulfur-based supported environmental remediation material. The mixing time in step (1) is 48~72h; The flow rate of the reducing gas in step (2) is 100~150 mL / min; The iron-sulfur-based supported environmental remediation material comprises a carrier and iron-sulfur-based materials dispersed on the surface and in the framework structure of the carrier; the iron-sulfur-based materials have a particle size of 100-300 nm and a specific surface area of ​​50-100 m². 2 / g; the particle size of the iron-sulfur-based supported environmental remediation material is 0.5~50μm; The carrier includes any one or a combination of at least two of aluminosilicates, activated carbon, or chitosan; The iron-sulfur based materials include ferrous sulfide and elemental iron.

2. The preparation method according to claim 1, characterized in that, The raw materials for the ferrous sulfate solution in step (1) include any one or a combination of at least two of analytical grade ferrous sulfate, industrial ferrous sulfate, or industrial ferrous sulfate waste salt.

3. The preparation method according to claim 2, characterized in that, The raw material for the ferrous sulfate solution in step (1) is analytical grade ferrous sulfate.

4. The preparation method according to claim 1, characterized in that, The concentration of the ferrous sulfate solution in step (1) is 10~30 wt.%.

5. The preparation method according to claim 4, characterized in that, The concentration of the ferrous sulfate solution in step (1) is 20~30 wt.%.

6. The preparation method according to claim 1, characterized in that, The liquid-to-solid ratio of the ferrous sulfate solution to the carrier in step (1) is (50~500):1mL / g.

7. The preparation method according to claim 6, characterized in that, The liquid-to-solid ratio of the ferrous sulfate solution to the carrier in step (1) is (100~250):1mL / g.

8. The preparation method according to claim 1, characterized in that, The mixing in step (1) includes any one or a combination of at least two of mechanical stirring, ultrasonic dispersion or oscillatory dispersion.

9. The preparation method according to claim 8, characterized in that, The mixing in step (1) is mechanical stirring.

10. The preparation method according to claim 9, characterized in that, The mechanical stirring speed is 100~400 r / min.

11. The preparation method according to claim 10, characterized in that, The mechanical stirring speed is 200~300 r / min.

12. The preparation method according to claim 1, characterized in that, The drying process in step (1) includes any one or a combination of at least two of vacuum drying, freeze drying, or oven drying.

13. The preparation method according to claim 12, characterized in that, The drying process described in step (1) is freeze drying.

14. The preparation method according to claim 1, characterized in that, Before the reduction reaction described in step (2), the temperature is raised to 400~900℃ under a first inert atmosphere.

15. The preparation method according to claim 14, characterized in that, Before the reduction reaction described in step (2), the temperature is raised to 400~500℃ under a first inert atmosphere.

16. The preparation method according to claim 15, characterized in that, The first inert atmosphere includes any one or a combination of at least two of nitrogen atmosphere, argon atmosphere, or helium atmosphere.

17. The preparation method according to claim 16, characterized in that, Step (2) The first inert atmosphere is achieved by continuously introducing inert gas.

18. The preparation method according to claim 17, characterized in that, The flow rate of the inert gas is 5~800 mL / min.

19. The preparation method according to claim 18, characterized in that, The flow rate of the inert gas is 100~400 mL / min.

20. The preparation method according to claim 1, characterized in that, The reducing atmosphere in step (2) includes a hydrogen atmosphere or a carbon monoxide atmosphere.

21. The preparation method according to claim 20, characterized in that, The reducing atmosphere in step (2) is a hydrogen atmosphere.

22. The preparation method according to claim 1, characterized in that, The reducing atmosphere in step (2) is achieved by continuously introducing a reducing gas.

23. The preparation method according to claim 1, characterized in that, The temperature of the reduction reaction in step (2) is 400~500℃.

24. The preparation method according to claim 1, characterized in that, The reduction reaction in step (2) takes 0.5 to 5 hours.

25. The preparation method according to claim 24, characterized in that, The reduction reaction in step (2) takes 0.5 to 2.5 hours.

26. The preparation method according to claim 1, characterized in that, After the reduction reaction described in step (2), the temperature is lowered to 20~30℃ in a second inert atmosphere.

27. The preparation method according to claim 26, characterized in that, The second inert atmosphere includes any one or a combination of at least two of nitrogen, argon, or helium atmospheres.

28. The preparation method according to claim 26, characterized in that, Step (2) The second inert atmosphere is achieved by continuously introducing inert gas.

29. The preparation method according to claim 28, characterized in that, The flow rate of the inert gas is 5~800 mL / min.

30. The preparation method according to claim 29, characterized in that, The flow rate of the inert gas is 100~400 mL / min.

31. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) After mixing ferrous sulfate solution and carrier at a liquid-to-solid ratio of (50~500):1mL / g for 24~120h, the mixture is subjected to solid-liquid separation and drying to obtain the reduction precursor. The raw materials for the ferrous sulfate solution include any one or a combination of at least two of analytical grade ferrous sulfate, industrial ferrous sulfate, or industrial ferrous sulfate waste salt; the concentration of the ferrous sulfate solution is 10~30 wt.%; the carrier includes any one or a combination of at least two of aluminosilicate, activated carbon, or chitosan; the mixing includes any one or a combination of at least two of mechanical stirring, ultrasonic dispersion, or oscillating dispersion; the drying treatment includes any one or a combination of at least two of vacuum drying, freeze drying, or oven drying. (2) The reduction precursor is heated to 400~900℃ in the first inert atmosphere and then subjected to a reduction reaction at 400~900℃ for 0.5~5h in the reducing atmosphere. After that, it is cooled to 20~30℃ in the second inert atmosphere to obtain the iron-sulfur-based supported environmental remediation material. The first inert atmosphere includes any one or a combination of at least two of nitrogen, argon, or helium atmospheres; the first inert atmosphere is achieved by continuously introducing an inert gas; the flow rate of the inert gas is 5~800 mL / min; The reducing atmosphere includes a hydrogen atmosphere or a carbon monoxide atmosphere; the reducing atmosphere is achieved by continuously introducing a reducing gas; the flow rate of the reducing gas is 5~400 mL / min; The second inert atmosphere includes any one or a combination of at least two of nitrogen, argon, or helium atmospheres; the second inert atmosphere is achieved by continuously introducing an inert gas; the flow rate of the inert gas is 5~800 mL / min.

32. The use of an iron-sulfur-based supported environmental remediation material prepared by the method described in claim 1, characterized in that, The iron-sulfur-based loaded environmental remediation material is applied to permeable reactive walls for soil and groundwater contaminated with heavy metals and / or organic matter.

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