Composition with dispersing function and reducing material and preparation method and application thereof

Abstract

The invention relates to the field of reducing materials, and discloses a composition with a dispersing function, a reducing material, a preparation method and an application thereof, wherein the composition comprises polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic minerals. The reducing material prepared by the composition with a dispersing function has good stability, a particle size distribution D90 of 1000nm, very good stability and a large specific surface area, good reaction activity, and can effectively remove pollutants such as heavy metals and chlorinated organic matter in soils with different pH values, with a removal rate of more than 99.5%.

Description

Technical Field

[0001] The invention relates to the field of reducing materials, and in particular to a composition and reducing material with a dispersing function, and a preparation method and application thereof. Background Art

[0002] Heavy metals in the soil, such as Pb, Hg, Cd, Zn, As, Cr, Cu, Ni, etc., are hidden, long-term, and irreversible. Due to their toxicity, bioaccumulation effects, and environmental persistence, they harm animals and plants through the food chain and even human health, thus creating ecological risks. It is a common method of soil heavy metal remediation to reduce the mobility and bioavailability of heavy metal substances in the environment by using chemical agents to produce adsorption, precipitation, and complexation with heavy metals in the soil.

[0003] In addition to common organic and inorganic passivators, nano-iron-based material passivators have also attracted much attention. Nanomaterials have large specific surface area, high reactivity, are easy to obtain and inexpensive. Ferrous sulfide (FeS) can effectively reduce heavy metal ions because it can provide Fe(II) and S(-II), both of which are strong reducing substances. Compared with FeS minerals, FeS nanoparticles have a higher reduction effect on heavy metal cations due to their small particle size and large specific surface area. However, FeS nanoparticles are prone to agglomeration, which reduces the reactive sites and reduces the reduction efficiency of heavy metal cations, thus resulting in certain restrictions on the use of nano-ferrous sulfide. At present, some research has been conducted on the problem of easy agglomeration of FeS nanomaterials.

[0004] CN202110991278.X discloses a composite material for efficiently treating hexavalent chromium pollution in the environment, and its preparation method and application, wherein the composite material is an ascorbic acid-modified nano-ferrous sulfide composite material. The preparation method is as follows: in a nitrogen environment, a certain amount of ascorbic acid is evenly dispersed in deoxygenated water, and ferrous sulfate solution and sodium sulfide solution are added in sequence, and an ascorbic acid-modified nano-ferrous sulfide suspension is obtained by coprecipitation reaction. After standing, the obtained solid phase is vacuum freeze-dried to obtain an ascorbic acid-modified nano-ferrous sulfate composite material.

[0005] CN201911178224.0 discloses the preparation and application of a chitosan-stabilized ferrous sulfide composite biochar material. Highland barley crop straw in plateau areas is used as the biochar raw material, and chitosan is used as a stabilizer for ferrous sulfide. The stability of ferrous sulfide is improved, and the ferrous sulfide is more evenly loaded on the biochar, thereby enhancing the treatment effect on hexavalent chromium.

[0006] However, these existing studies all use the solution precipitation reaction modification method to prepare nano-scale ferrous sulfide solid materials. It is difficult to completely homogenize the solid material and clay reaction, resulting in poor results. The prepared nano-scale ferrous sulfide sol product has a low concentration and low yield. Therefore, for the remediation of clay pollution, how to prepare materials with high permeability in large quantities has become the main problem that needs to be solved in current engineering remediation. Summary of the invention

[0007] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a composition and reducing material with dispersing function and a preparation method and application thereof.

[0008] In order to achieve the above object, the present invention provides a composition with dispersing function in a first aspect, wherein the composition comprises polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral.

[0009] A second aspect of the present invention provides a reducing material containing ferrous sulfide, characterized in that the reducing material comprises the above composition and ferrous sulfide.

[0010] The third aspect of the present invention provides a method for preparing a reducing material, characterized in that the method comprises: in the presence of water and the above-mentioned composition, 2+ and S 2- Contact to react.

[0011] A fourth aspect of the present invention provides a reducing material prepared by the above method.

[0012] A fifth aspect of the present invention provides an application of the above-mentioned material in the reduction and remediation of heavy metals and / or organic pollutants in soil.

[0013] Through the above technical solution, the present invention has at least the following beneficial effects:

[0014] (1) By combining polyethylene glycol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral composition, the four components work synergistically and none of them can be missing, which can make ferrous sulfide form a high-concentration and high-permeability reducing material with good stability, an average diameter of 50 to 500 nm, very good stability and a large specific surface area, and good reaction activity. It can effectively remove heavy metals, chlorinated organic matter and other pollutants in soils with different pH values, with a removal rate of more than 99.5%;

[0015] (2) The preparation method provided, ferrous sulfide (FeS) can effectively reduce heavy metal ions, it can provide Fe(II) and S(-II), both of which are strong reducing substances. Nano-sized FeS particles have a strong reducing effect on heavy metal cations, chlorinated organic matter, etc. due to their small particle size and large specific surface area;

[0016] (3) The high-concentration and high-permeability reducing material provided has FeS nanoparticles uniformly dispersed in the solution, which solves the problem of easy agglomeration and reduced reactive sites. At the same time, it exists in the solution in the form of a sol and has high permeability characteristics. It has good application prospects in the remediation of sticky contaminated soils. The FeS concentration is high but it is not easy to agglomerate, so it has a strong reducing effect while ensuring high permeability.

[0017] (4) The raw materials used to prepare high-concentration and high-permeability reducing materials are widely available and low in cost. The technical process is safe, green and energy-saving. There are no high requirements for equipment during the preparation process. It has high economic utilization and can treat pollution such as heavy metals and chlorinated organic matter in soil and groundwater in situ or ex situ. It has the advantages of low cost, short processing time and simple and easy operation. DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] One aspect of the present invention provides a composition with dispersing function, wherein the composition comprises polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral.

[0020] Preferably, the content of the polyether polyol is 50-80% by weight of the total weight of the composition, for example, it may be 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the polyether polyol is polyethylene glycol, and the weight average molecular weight of the polyethylene glycol is 200-8000.

[0022] Preferably, the content of diethylene glycol monobutyl ether is 10-20% by weight of the total weight of the composition, for example, 10%, 15% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the content of the polyacrylate is 5-20% by weight of the total weight of the composition, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18% or 20%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the weight average molecular weight of the polyacrylate is 1,000,000-30,000,000.

[0025] Preferably, the polyacrylate is at least one of sodium polyacrylate and potassium polyacrylate.

[0026] Preferably, the content of the inorganic mineral is 5-10% by weight of the total weight of the composition, for example, it can be 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the inorganic mineral is at least one of albite, potassium feldspar and calcium feldspar, a typical but non-limiting combination is a combination of albite and calcium feldspar, and the weight ratio of albite to calcium feldspar is preferably 1.15-2.75:1.

[0028] Preferably, the inorganic mineral particle size is 10~100nm, for example, it can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, and more preferably 40~80nm.

[0029] Preferably, the weight ratio of polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral is 10:1~4:0.6~4:0.6~2.

[0030] A second aspect of the present invention provides a reducing material containing ferrous sulfide, characterized in that the reducing material comprises the above composition and ferrous sulfide.

[0031] Preferably, the content of ferrous sulfide is 5-1250 g per gram of the composition.

[0032] Preferably, the particle size distribution D90 of the ferrous sulfide is 1000 nm, that is, 90% of the particle size of the ferrous sulfide is less than or equal to 1000 nm. In the present invention, the particle size of the material will affect its distribution uniformity and activity.

[0033] Preferably, the reducing material also includes water, and the concentration of ferrous sulfide in the reducing material is 1-250 g / L, for example, 1 g / L, 5 g / L, 10 g / L, 50 g / L, 100 g / L, 150 g / L, 200 g / L or 250 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, more preferably 50-200 g / L.

[0034] In the present invention, the concentration of the composition is 0.01 to 0.5% by weight, for example, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35% or 4% by weight, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, more preferably 0.05 to 0.25% by weight. In the present invention, controlling the concentration of the composition within the above preferred range can more effectively avoid the aggregation and precipitation of ferrous sulfide and promote the uniform dispersion of ferrous sulfide at a lower cost.

[0035] The third aspect of the present invention provides a method for preparing a reducing material, characterized in that the method comprises: in the presence of water and the above-mentioned composition, 2+ and S 2- Contact to react.

[0036] In the present invention, Fe 2+ and S 2- It can be provided by materials commonly used in the art. Preferably, the Fe 2+ Provided by FeSO4. Preferably, the S 2- Provided by Na2S.

[0037] In the present invention, Fe 2+ and S 2- The amount used is sufficient to generate ferrous sulfide. Preferably, the Fe 2+ and S 2- The molar ratio is 0.5-1.5:1, for example, 0.5:1, 0.75:1, 1:1, 1.25:1 or 1.5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, more preferably 0.8-1.2:1.

[0038] Preferably, relative to each gram of the composition, Fe 2+ The dosage is 3~800g.

[0039] In the present invention, the amount of water used is preferably 4000-8000 mL per gram of the composition.

[0040] In the present invention, the contact conditions may include: an oxygen-free atmosphere, a temperature of 20-80° C., and a time of 20-180 min.

[0041] Preferably, the method further comprises: performing solid-liquid separation after the reaction, mixing the solid phase with water, and performing wet ball milling to obtain a sol-like material. Wherein, the amount of water used can be 4 to 1000 mL relative to each gram of solid phase. Preferably, the wet ball milling time is 5 to 30 min, for example, it can be 5 min, 10 min 15 min, 20 min, 25 min, or 30 min, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, more preferably 10 to 20 min, the ball milling medium is zirconium oxide, the particle size is 0.3 to 0.4 mm, and the ball-to-material weight ratio is 1: 0.25 to 10. In the present invention, controlling the ball milling time can achieve the grinding effect without causing the material to re-agglomerate.

[0042] In the present invention, in order to avoid the addition of additional ions affecting the reaction process and the reduction of the materials, the water used in the above method is preferably distilled water.

[0043] Preferably, the solid-liquid separation method is filtration, more preferably vacuum filtration or plate and frame filter press.

[0044] Preferably, the vacuum filtration condition is: 0.1MPa≤working pressure≤0.5MPa. The working pressure of vacuum filtration refers to the positive pressure value generated by the oil pump.

[0045] Preferably, the conditions for the plate and frame filtration are: 0.1 MPa≤working pressure≤1.6 MPa.

[0046] In the present invention, the method specifically comprises:

[0047] (1) The composition is dispersed in water;

[0048] (2) The product obtained in step (1) is mixed with Fe 2+ Solution mixing;

[0049] (3) The product obtained in step (2) is mixed with S 2- Solution mixing;

[0050] (4) performing solid-liquid separation on the product obtained in step (3);

[0051] (5) The solid phase obtained in step (4) is mixed with water and subjected to wet ball milling to obtain a sol-like material.

[0052] In the present invention, the composition in step (1) is dispersed in water by heating and stirring, and the heating temperature is 40-90°C, for example, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable, and it is more preferably 50-80°C. The heating temperature will affect the dispersion effect. The stirring rate is 200-450r / min, for example, it can be 200r / min, 250r / min, 300r / min, 350r / min, 400r / min or 450r / min, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable, and it is more preferably 250-350 r / min.

[0053] Preferably, the mixing conditions in step (2) include: an oxygen-free atmosphere.

[0054] In the present invention, the temperature in step (2) is 20-50° C. and the time is 5-30 min.

[0055] In the present invention, the mixing conditions in step (3) include: an oxygen-free atmosphere, a temperature of 40-80° C., and a time of 20-120 min, for example, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, etc., but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, and more preferably 50-90 min.

[0056] Preferably, the oxygen-free atmosphere is formed by introducing an oxygen-free gas. In the present invention, the oxygen-free gas refers to a gas that does not contain oxygen and does not react with raw materials in the system, and is more preferably at least one of nitrogen, a rare gas and hydrogen.

[0057] The preparation method provided by the present invention is that the organic component in the organic-inorganic mixed dispersant can change the double electric layer electrical properties of the FeS surface, generate a hydrophilic hydration film, and increase the steric hindrance of the FeS particle surface, which increases the stability of the FeS particle system in the solution. At the same time, the zero electric point of the inorganic component is close to the zero electric point of the FeS nanoparticles, so that in the same solution, the FeS nanoparticles and the mineral surface will have the same electrical properties, and the two will repel each other, which can also enhance the purpose of FeS particle dispersion.

[0058] In the present invention, for the convenience of transportation and application of the material, the salt generated in the reaction process is separated by filtration to reduce the secondary contamination of the salt in the product, and then distilled water is added to adjust the concentration and grind to obtain a high-concentration and high-osmotic reducing material.

[0059] The starting materials within the scope of the present invention can be almost completely reacted into the products.

[0060] A fourth aspect of the present invention provides a reducing material prepared by the above method.

[0061] A fifth aspect of the present invention provides an application of the above-mentioned material in the reduction and remediation of heavy metals and / or organic pollutants in soil.

[0062] The mass ratio of heavy metals and / or organic pollutants to FeS is 1:1~12.

[0063] The present invention will be described in detail below through examples. In the following examples, the weight average molecular weight of polyethylene glycol is 600, the weight average molecular weight of sodium polyacrylate is 30,000,000, and the weight average molecular weight of potassium polyacrylate is 10,000,000.

[0064] The particle size of ferrous sulfide was measured and analyzed by Malvern MASTERSIZER 2000 particle size analyzer.

[0065] Example 1

[0066] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0067] (1) Polyethylene glycol, diethylene glycol monobutyl ether, sodium polyacrylate, and albite (particle size 10 nm) were mixed in a weight ratio of 5:2:2:1, heated at 60°C, and stirred at 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0068] (2) 65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under a nitrogen atmosphere at 30°C, and stirring was continued for 20 min;

[0069] (3) 65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under a nitrogen atmosphere and a heating and stirring environment at 60°C, and the stirring was continued for 30 min to obtain a high-concentration and high-permeability reduced material initial product;

[0070] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.5 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0071] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.3 mm. The ball-to-material weight ratio was 1:10 to obtain a reducing material with a ferrous sulfide concentration of 100 g / L.

[0072] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0073] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0074] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 5:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality - Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 100%.

[0075] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 4:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 99% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0076] Example 2

[0077] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0078] (1) Polyethylene glycol, diethylene glycol monobutyl ether, sodium polyacrylate, and albite (particle size 100 nm) were mixed in a weight ratio of 5:2:2:1, heated at 80°C, and stirred at 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0079] (2) 65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under a nitrogen atmosphere at 50°C, and stirring was continued for 30 min;

[0080] (3) 65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under a nitrogen atmosphere and a heating and stirring environment at 80°C, and the stirring was continued for 30 min to obtain a high-concentration and high-permeability reduced material initial product;

[0081] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.3 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0082] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.4 mm and a ball-to-material weight ratio of 1:5 to obtain a reducing material with a ferrous sulfide concentration of 100 g / L.

[0083] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0084] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 10:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0085] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 5:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality - Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 100%.

[0086] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 8:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 98% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0087] Example 3

[0088] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0089] (1) Polyethylene glycol, diethylene glycol monobutyl ether, potassium polyacrylate, and albite (particle size 50 nm) were mixed in a weight ratio of 5:2:2:1, heated to 80°C, and stirred at 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0090] (2) 65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under an argon atmosphere at 20°C, and stirring was continued for 30 min;

[0091] (3) 65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under an argon atmosphere and a heating and stirring environment at 40°C, and the stirring was continued for 30 min to obtain a high-concentration and high-permeability reduced material initial product;

[0092] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.1 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0093] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.4 mm. The ball-to-material weight ratio was 1:3 to obtain a reducing material with a ferrous sulfide concentration of 100 g / L.

[0094] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0095] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0096] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 3:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality - Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 100%.

[0097] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 98% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0098] Example 4

[0099] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0100] (1) Polyethylene glycol, diethylene glycol monobutyl ether, sodium polyacrylate, and albite (particle size 50 nm) were mixed in a weight ratio of 16:2:1:1, heated at 60°C, and stirred at 300 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0101] (2) 0.65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under an argon atmosphere at 20°C, and stirring was continued for 20 min;

[0102] (3) 0.65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under an argon atmosphere and a heating and stirring environment at 40°C, and the stirring was continued for 20 minutes to obtain a high-concentration and high-permeability reduction material initial product;

[0103] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.1 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0104] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.4 mm. The ball-to-material weight ratio was 1:10 to obtain a reducing material with a ferrous sulfide concentration of 1 g / L.

[0105] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0106] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0107] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 3:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality - Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 100%.

[0108] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 98% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0109] Example 5

[0110] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0111] (1) Polyethylene glycol, diethylene glycol monobutyl ether, potassium polyacrylate, and albite (particle size 10 nm) were mixed in a weight ratio of 5:2:2:1, heated at 80°C, and stirred at 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0112] (2) 32.5 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under a nitrogen atmosphere at 20°C, and stirring was continued for 30 min;

[0113] (3) 32.5 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under a nitrogen atmosphere at 40°C, and the stirring was continued for 60 min to obtain a high-concentration and high-permeability reduced material initial product;

[0114] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.4 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0115] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.4 mm. The ball-to-material weight ratio was 1:5 to obtain a reducing material with a ferrous sulfide concentration of 50 g / L.

[0116] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0117] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0118] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 3:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality - Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 100%.

[0119] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 5:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 98% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0120] Example 6

[0121] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0122] (1) Polyethylene glycol, diethylene glycol monobutyl ether, potassium polyacrylate, and potassium feldspar (particle size 50 nm) were mixed in a weight ratio of 5:2:2:1, heated to 80°C, and stirred at 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0123] (2) 65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under a nitrogen atmosphere at 40°C, and stirring was continued for 30 min;

[0124] (3) 65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was added dropwise to the solution obtained in step (2) under a nitrogen atmosphere at 60°C, and the stirring was continued for 30 min to obtain a high-concentration and high-permeability reduced material initial product;

[0125] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.3 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0126] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.3 mm. The ball-to-material weight ratio was 1:10 to obtain a reducing material with a ferrous sulfide concentration of 100 g / L.

[0127] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D90 is 1000 nm.

[0128] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 6:1. After reacting for 72 hours, the removal rate of Cr(VI) was 100% according to the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019).

[0129] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 6:1. After 72 hours of reaction, the soil quality of lead and cadmium was determined by graphite furnace atomic absorption spectrophotometry (GB / T 17141-1997). 2+ The removal rate is 100%.

[0130] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 4:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 98% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0131] Example 7

[0132] This embodiment provides a method for preparing a high-concentration and high-permeability reducing material, and the specific preparation method is as follows:

[0133] (1) Polyethylene glycol, diethylene glycol monobutyl ether, potassium polyacrylate, and potassium feldspar (particle size 10 nm) were mixed in a weight ratio of 5:2:2:1, heated to 80°C, and stirred at a rate of 250 r / min to prepare 40 mL of a 0.1 wt% composition having a dispersing function;

[0134] (2) 65 g of FeSO4·7H2O was dissolved in 100 mL of distilled water to prepare a FeSO4 solution, and then 40 mL of the 0.1 wt% aqueous solution of the composition obtained in step (1) was added to the FeSO4 solution under a nitrogen atmosphere at 20°C, and the stirring was continued for 10 min;

[0135] (3) 65 g of Na2S·9H2O was dissolved in 60 mL of distilled water to prepare a Na2S solution, and the Na2S solution was slowly added dropwise to the solution obtained in step (2) under a nitrogen atmosphere at 40°C, and stirring was continued for 30 min to obtain a high-concentration and high-permeability reduced material initial product;

[0136] (4) vacuum filtering the high-concentration and high-permeability reduced material product obtained in step (3) at a working pressure of 0.2 MPa to obtain a high-concentration and high-permeability reduced material crude product dry material;

[0137] (5) The high-concentration and high-permeability reducing material obtained in step (4) was added to 200 mL of distilled water and ground for 15 min. The grinding medium was made of zirconium oxide with a diameter of 0.3 mm. The ball-to-material weight ratio was 1:20 to obtain a reducing material with a concentration of 100 g / L ferrous sulfide.

[0138] The high-concentration and high-permeability reducing material prepared in this embodiment is in a sol state, and its particle size distribution D50 is 1000 nm and D90 is 5 μm.

[0139] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in Cr(VI) were mixed in a mass ratio of 2:1. After reacting for 72 hours, the removal rate of Cr(VI) was tested by the national standard test method of "Determination of Hexavalent Chromium in Soil and Sediment" (HJ 1082-2019), and the result was 90%.

[0140] The high concentration and high permeability reducing material based on FeS and Cd 2+ The soil was mixed with the calculated mass ratio of 2.5:1. After 72 hours of reaction, the soil was tested for Cd using the method of “Determination of lead and cadmium in soil quality-Graphite furnace atomic absorption spectrophotometry” (GB / T 17141-1997). 2+ The removal rate is 95%.

[0141] The high-concentration and high-permeability reducing material measured in FeS and the soil measured in vinyl chloride were mixed in a mass ratio of 2:1. After reacting for 72 hours, the removal rate of vinyl chloride was detected to be 92% using the "Determination of Volatile Organic Compounds in Soil and Sediment Headspace / Gas Chromatography-Mass Spectrometry" (HJ642).

[0142] Example 8

[0143] The method of Example 1 is followed, except that the grinding time in step (5) is 60 min;

[0144] The result was a material that was somewhat sedimentary, with agglomerates settling to the bottom after a few days.

[0145] Under the same operating conditions, the obtained material has a removal rate of 85% for hexavalent chromium, 83% for cadmium ions, and 85% for vinyl chloride.

[0146] Example 9

[0147] The method of Example 1 is followed, except that in step (1), the weight ratio of polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral is 10:6:6:10;

[0148] The result was a material that was somewhat sedimentary, with agglomerates settling to the bottom after a few days.

[0149] Under the same operating conditions, the obtained material has a removal rate of 80% for hexavalent chromium, 80% for cadmium ions, and 85% for vinyl chloride.

[0150] Comparative Example 1

[0151] The method of Example 1 is followed, except that in step (1), only albite inorganic dispersant is used.

[0152] The result was a material that was slightly more sedimentable, with agglomerates settling to the bottom after a few days.

[0153] Under the same operating conditions, the obtained material has a removal rate of 86% for hexavalent chromium, 88% for cadmium ions, and 90% for vinyl chloride.

[0154] Comparative Example 2

[0155] The method of Example 1 is followed, except that in step (1), only polyethylene glycol is used as an organic dispersant.

[0156] The result was a material that was slightly more sedimentable, with agglomerates settling to the bottom after a few days.

[0157] Under the same operating conditions, the obtained material has a removal rate of 65% for hexavalent chromium, 60% for cadmium ions, and 50% for vinyl chloride.

[0158] Comparative Example 3

[0159] The method of Example 1 is followed, except that in step (1), only diethylene glycol monobutyl ether is used as the organic dispersant.

[0160] The result was a material that was somewhat sedimentary, with agglomerates settling to the bottom after a few days.

[0161] Under the same operating conditions, the removal rate of hexavalent chromium, cadmium ions and vinyl chloride by the obtained material was 72%, 67% and 58%, respectively.

[0162] Comparative Example 4

[0163] The method of Example 1 is followed, except that in step (1), only sodium polyacrylate organic dispersant is used.

[0164] The result was a material that was somewhat sedimentary, with agglomerates settling to the bottom after a few days.

[0165] Under the same operating conditions, the obtained material has a removal rate of 65% for hexavalent chromium, 60% for cadmium ions, and 85% for vinyl chloride.

[0166] Comparative Example 5

[0167] The method of Example 1 is followed, except that in step (1), only albite and potassium feldspar inorganic dispersants are used.

[0168] The result was a material that was slightly more sedimentable, with agglomerates settling to the bottom after a few days.

[0169] Under the same operating conditions, the obtained material has a removal rate of 62% for hexavalent chromium, 70% for cadmium ions, and 50% for vinyl chloride.

[0170] The following points can be seen from the examples and comparative examples:

[0171] (1) It can be seen from Example 1 and Comparative Examples 1 to 4 that the organic and inorganic dispersants play a common dispersing role, and the materials can be mixed uniformly and stably;

[0172] (2) It can be seen from Example 1 and Example 8 that the obtained material cannot be completely nanoscale. This is because the material preparation concentration is high, the grinding time is too long, and the material agglomerates during the grinding process, resulting in an increase in particle size. It cannot form a sol state, and the permeability in the soil decreases.

[0173] In summary, the present invention provides a method for preparing a high-concentration and high-permeability reducing material. Through the combination of raw materials and the action of a dispersant, the high-concentration and high-permeability reducing material of the present invention is obtained. This material has a reducing ferrous sulfide sol material with a smaller particle size, a larger specific surface area, stronger permeability and stronger reaction efficiency. The reducing sol material can significantly improve the repair ability of clay pollution and has good application prospects.

[0174] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a reducing material, characterized in that: The method includes: (1) dispersing the composition in water; (2) The product obtained in step (1) is mixed with Fe 2+ Solution mixing; (3) The product obtained in step (2) is mixed with S 2- The solutions are mixed to react; (4) performing solid-liquid separation on the product obtained in step (3); (5) mixing the solid phase obtained in step (4) with water and performing wet ball milling to obtain a reduced material containing ferrous sulfide; Wherein, the mixing conditions in steps (2) and (3) include: an oxygen-free atmosphere; The ball milling time is 5 to 30 minutes; The ball milling medium is zirconium oxide, with a particle size of 0.3-0.4 mm and a ball-to-material weight ratio of 1:0.25-10; The composition comprises polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral; The weight ratio of polyether polyol, diethylene glycol monobutyl ether, polyacrylate and inorganic mineral is 10:1-4:0.6-4:0.6-2; the content of the polyether polyol accounts for 50-80% by weight of the total weight of the composition; Wherein, the polyether polyol is polyethylene glycol, and the weight average molecular weight of the polyethylene glycol is 200-8000; The weight average molecular weight of the polyacrylate is 1,000,000 to 30,000,000; The polyacrylate is at least one of sodium polyacrylate and potassium polyacrylate; The inorganic mineral is at least one of albite, potassium feldspar and calcium feldspar; The particle size of the inorganic mineral is 10-100 nm; Wherein, the concentration of ferrous sulfide in the reducing material is 1-250 g / L; The content of ferrous sulfide is 5-1250 g per gram of the composition.

2. The method according to claim 1, wherein: The content of diethylene glycol monobutyl ether accounts for 10-20% by weight of the total weight of the composition; and / or, the content of the polyacrylate is 5-20% by weight of the total weight of the composition; And / or, the content of the inorganic mineral is 5-10 weight % of the total weight of the composition.

3. The method according to claim 1 or 2, wherein: The inorganic minerals are albite and anorthite, and the weight ratio of albite to anorthite is 1.15-2.75:

1.

4. The method according to claim 3, wherein: The particle size of the inorganic mineral is 40-80 nm.

5. The method according to claim 1 or 2, wherein: The Fe 2+ Provided by FeSO4; and / or, the S 2- Provided by Na2S; And / or, the Fe 2+ and S 2- The molar ratio is 0.5~1.5:1; And / or, the amount of water used is 4000-8000 mL per gram of the composition.

6. The method according to claim 5, wherein: The Fe 2+ and S 2- The molar ratio is 0.8~1.2:

1.

7. The method according to claim 1 or 2, wherein: The ball milling time is 10 to 20 minutes; And / or, the water is distilled water; And / or, the solid-liquid separation method is filtration.

8. The method according to claim 7, wherein: The filtration is vacuum filtration, and the conditions of vacuum filtration are: 0.1MPa≤working pressure≤0.5MPa.

9. The method according to claim 7, wherein: The filtration is plate and frame filter pressing, and the conditions of the plate and frame filter pressing are: 0.1MPa≤working pressure≤1.6MPa.

10. The method according to claim 1 or 2, wherein: The oxygen-free atmosphere is provided by introducing an oxygen-free gas, wherein the oxygen-free gas is at least one of nitrogen, a rare gas and hydrogen.

11. The reduced material prepared by the method according to any one of claims 1 to 10.

12. Use of the reducing material according to claim 11 in the reduction and remediation of heavy metals and / or organic pollutants in soil.