阅读说明：本技术 一种铁基土壤修复材料及其制备方法、装置和应用 (Iron-based soil remediation material and preparation method, device and application thereof ) 是由 罗章 向猛 李耀辉 杜鹏 尹交英 于 2019-09-10 设计创作，主要内容包括：本发明提供了一种铁基土壤修复材料及其制备方法、装置和应用。该制备方法包括将零价铁与强酸溶液混合,在50-70℃之间,反应1-4h,再将零价铁与硫化钠和柠檬酸溶液混合,继续反应0.5-1h后得到所述铁基土壤修复材料。该制备方法能够将零价铁原有铁氧化物壳层转变成柠檬酸改性的硫铁矿壳层,强化零价铁的腐蚀能力和迁移能力,提升污染物的去除效果,将得到的铁基土壤修复材料投入重金属土壤中,修复效果显著。(The invention provides an iron-based soil remediation material, and a preparation method, a device and application thereof. The preparation method comprises the steps of mixing zero-valent iron and a strong acid solution, reacting for 1-4 hours at 50-70 ℃, mixing the zero-valent iron with sodium sulfide and a citric acid solution, and continuously reacting for 0.5-1 hour to obtain the iron-based soil remediation material. The preparation method can convert the original iron oxide shell of the zero-valent iron into the citric acid modified pyrite shell, strengthen the corrosion capability and the migration capability of the zero-valent iron, improve the removal effect of pollutants, and has remarkable repair effect when the obtained iron-based soil repair material is thrown into heavy metal soil.)

1. A preparation method of an iron-based soil remediation material is characterized by comprising the following steps: the iron-based soil remediation material is prepared by mixing zero-valent iron and a strong acid solution, reacting for 1-4 hours at 50-70 ℃, mixing the zero-valent iron with sodium sulfide and a citric acid solution, and continuing to react for 0.5-1 hour.

2. The method of claim 1, wherein: the strong acid solution comprises any one of hydrochloric acid, sulfuric acid and nitric acid, and the concentration of the strong acid solution is 1-5 mol/L.

3. The method of claim 1, wherein: the grain size of the zero-valent iron is higher than 70 um.

4. The method of claim 1, wherein: the concentration of the sodium sulfide solution is 0.1-0.3mol/L, and the concentration of the citric acid solution is 0.01-0.05 mol/L.

5. The method of claim 1, wherein: the method specifically comprises the steps of mixing zero-valent iron and a strong acid solution, reacting for 3-4 hours at 55-60 ℃, then carrying out solid-liquid separation, mixing the zero-valent iron with sodium sulfide and a citric acid solution, continuing to react for 0.5-0.8 hour, and then carrying out solid-liquid separation to obtain the iron-based soil remediation material.

6. An iron-based soil remediation material produced by the method of any one of claims 1 to 5.

7. An apparatus for preparing an iron-based soil remediation material as claimed in claim 6, wherein: the device comprises a reaction device, wherein two sides of the reaction device are respectively connected with a solution storage device and an acid liquor storage device; and a heating electrode is arranged in the reaction device.

8. The manufacturing apparatus according to claim 7, characterized in that: the reaction device, the solution storage device and the acid liquor storage device are communicated through a circulating pipeline, and the circulating pipeline is provided with a circulating pump.

9. Use of the iron-based soil remediation material of claim 6 for soil heavy metal remediation.

10. Use according to claim 9, characterized in that: the mass ratio of the iron-based soil remediation material to the heavy metal soil is 0.5-3: 100.

Technical Field

The invention relates to the technical field of soil pollution remediation, in particular to an iron-based soil remediation material, and a preparation method, a device and application thereof.

Background

With the rapid development of industry and agriculture, the heavy metal pollution of soil becomes more serious and is concerned widely. The causes of heavy metal pollution of soil mainly include natural sources and man-made interference input. Compared with organic pollutants, the heavy metals are not easily decomposed by soil microorganisms in the soil, but are enriched through a food chain, so that the heavy metals have important influence on the health of a human body. Therefore, the remediation of heavy metal contaminated soil is imminent.

The current soil heavy metal pollution remediation technology mainly comprises: soil-bearing method, solidification and stabilization, leaching technology, plant restoration and the like. The curing and stabilizing technology has become a hotspot for research and development and application due to the advantages of simple operation, economy, high efficiency and the like. The key to the success or failure of the repair effect of the solidification and stabilization technology lies in the performance of the medicament. The zero-valent iron has the characteristics of wide sources, multiple pollutant removal types, no secondary pollution and the like, and is considered to be an excellent stabilizing agent for repairing environmental pollution, particularly soil and underground water pollution. Although zero-valent iron has been used for environmental pollution remediation, there are some difficulties such as corrosion of zero-valent iron due to the presence of a passivation layer on the surface of zero-valent iron, and further increase of the surface passivation layer as the reaction proceeds to hinder removal of pollutants, and weak migration ability.

In order to solve the above problems, the prior art adopts the following common technical means: a. the weak magnetic field is used for strengthening zero-valent iron corrosion, and the formation of a passivation layer can be slowed down to promote the removal of pollutants; b. mechanically ball-milling zero-valent iron and sulfur-containing substances by using a high-energy ball mill to prepare sulfurized zero-valent iron so as to improve the pollutant removal capability of the zero-valent iron; c. the capacity of removing heavy metals from zero-valent iron is enhanced by using a liquid nitrogen pretreatment mode. Although the scheme can better strengthen the decontamination capability of the zero-valent iron, the iron oxide shell layer on the surface of the zero-valent iron is not changed substantially.

Disclosure of Invention

The invention aims to provide an iron-based soil remediation material, and a preparation method, a device and an application thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

A preparation method of an iron-based soil remediation material comprises the steps of mixing zero-valent iron and a strong acid solution, reacting for 1-4 hours at 50-70 ℃, mixing the zero-valent iron with a sodium sulfide and citric acid solution, and continuing to react for 0.5-1 hour to obtain the iron-based soil remediation material.

In a preferred embodiment, the strong acid solution includes any one of hydrochloric acid, sulfuric acid, and nitric acid, but is not limited thereto, and has a concentration of 1 to 5 mol/L.

In a preferred embodiment, the zero valent iron has a particle size of greater than 70 um.

In a preferred embodiment, the concentration of the sodium sulfide solution is 0.1-0.3mol/L, and the concentration of the citric acid solution is 0.01-0.05 mol/L.

In a better embodiment, the iron-based soil remediation material specifically comprises the steps of mixing zero-valent iron with a strong acid solution, reacting at 55-60 ℃ for 3-4 hours, then carrying out solid-liquid separation, mixing the zero-valent iron with sodium sulfide and a citric acid solution, continuing to react for 0.5-0.8 hour, and then carrying out solid-liquid separation to obtain the iron-based soil remediation material.

The invention also provides the iron-based soil remediation material prepared by the preparation method.

The invention also provides a preparation device using the preparation method, which comprises a reaction device, wherein two sides of the reaction device are respectively connected with a solution storage device and an acid liquor storage device; and a heating electrode is arranged in the reaction device.

The invention also provides a method for preparing the acid liquor, which is characterized in that the reaction device, the solution storage device and the acid liquor storage device are communicated through circulating pipelines, and the circulating pipelines are provided with circulating pumps.

The invention also provides an application of the iron-based soil remediation material in soil heavy metal remediation.

in a preferred embodiment, the mass ratio of the iron-based soil remediation material to the heavy metal soil is 0.5-3: 100.

The preparation method of the iron-based soil remediation material provides a novel zero-valent iron modification technology, firstly, a strong acid solution is used for treating and passivating zero-valent iron, then, sodium sulfide and a citric acid solution are added for modifying the zero-valent iron, and finally, solid-liquid separation is carried out to obtain the novel zero-valent iron N-L-Fe. The iron-based soil remediation material is characterized in that an original iron oxide shell of zero-valent iron is converted into a citric acid modified pyrite shell, the corrosion capability and the migration capability of the zero-valent iron are enhanced by regulating and controlling the hydrophilic property of the material shell, the iron-based soil remediation material is added into heavy metal soil according to a certain mass proportion, the heavy metal chromium contaminated soil can be effectively remedied, the remediation effect is as high as 99%, and the soil heavy metal remediation effect is excellent.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of the structure of a production apparatus of the present invention;

FIG. 2 is a graph showing the repairing efficiency of hexavalent chromium in example 1 of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In a preferred embodiment of the invention, the preparation method of the iron-based soil remediation material comprises the steps of mixing zero-valent iron with the particle size of more than 70um with a strong acid solution, reacting for 1-4h at 50-70 ℃, and then carrying out solid-liquid separation, wherein the zero-valent iron is derived from various iron-containing wastes, such as iron slag, industrial waste iron blocks, scrap iron and the like. The strong acid solution comprises any one of hydrochloric acid, sulfuric acid and nitric acid, and the concentration of the strong acid solution is 1-5 mol/L; and then mixing zero-valent iron with sodium sulfide with the concentration of 0.1-0.3mol/L and citric acid solution with the concentration of 0.01-0.05mol/L, continuously reacting for 0.5-1h, and performing solid-liquid separation to obtain the iron-based soil remediation material. The iron-based soil remediation material is mixed with heavy metal soil according to the mass ratio of 0.5-3:100, so that the heavy metal chromium-polluted soil can be effectively remedied, and the remediation effect is as high as 99%.

According to the illustration in fig. 1, in a preferred embodiment of the present invention, the device for preparing the iron-based soil remediation material by using the preparation method comprises a reaction device 1, wherein a solution storage device 2 and an acid storage device 3 are respectively connected to two sides of the reaction device 1; a heating electrode 4 is arranged in the reaction device 1. The reaction device 1, the solution storage device 2 and the acid liquor storage device 3 are communicated through a circulating pipeline 5, and the circulating pipeline 5 is provided with a circulating pump.

The reaction device 1 is provided with a feed inlet, a water inlet and a water outlet, and a heating electrode 4 is arranged inside the reaction device; the acid liquor storage device 3 and the solution storage device 2 are provided with water inlets and water outlets for connecting a circulating pipeline 5, and the solution is recycled through a circulating pump. The acid liquor storage device 3 is mainly used for the configuration of strong acid solution and the recycling of residual acid wastewater after the reaction is finished, and the top end of the acid liquor storage device 3 is opened and used for adding strong acid, measuring the pH value of the acid liquor and determining the amount of supplemented strong acid according to the pH value. The solution storage device 2 is mainly used for recycling the unreacted sulfur-containing and citric acid solution, and is similar to the acid solution storage device 3, and the upper end of the solution storage device is opened for supplementing the sodium sulfide and citric acid solution. During the reaction, the acid solution, the sodium sulfide and the citric acid solution respectively flow into the reaction device 1 through the circulating pipeline 5, and after the reaction is finished, the acid solution flows back to the corresponding storage device through the circulating pipeline 5, and newly prepared N-L-Fe is left in the reaction device 1 and is removed through the material outlet of the reaction device 1.

The technical solution of the present invention is further explained below with reference to several embodiments and corresponding diagrams.