WO2022222392A1

WO2022222392A1 - Diatomite-loaded biogenic iron-manganese oxide material, preparation method therefor, and application thereof

Info

Publication number: WO2022222392A1
Application number: PCT/CN2021/124213
Authority: WO
Inventors: 王华伟; 王亚楠; 孙英杰; 张艳茹; 刘梁丰
Original assignee: 青岛理工大学
Priority date: 2021-04-19
Filing date: 2021-10-15
Publication date: 2022-10-27
Also published as: CN113122530A; CN113122530B; AU2021441781A1

Abstract

A diatomite-loaded biogenic iron-manganese oxide material, a preparation method therefor, and an application thereof. The preparation method comprises: inoculating a strain into a culture medium containing divalent iron, divalent manganese, and diatomite to obtain a diatomite-loaded biogenic iron-manganese oxide material. The strain is a strain capable of converting the divalent iron and the divalent manganese into an iron-manganese oxide. According to the present invention, the diatomite is used as a carrier, the divalent iron and the divalent manganese are closely adsorbed on the diatomite in the form of an iron-manganese oxide under the action of the strain, and finally, the diatomite-loaded biogenic iron-manganese oxide material can be applied to remediation of arsenic-contaminated soil.

Description

A kind of diatomite-supported biological iron manganese oxide material and its preparation method and application

technical field

The invention belongs to soil remediation treatment technology, in particular to a diatomite-supported biological iron-manganese oxide material and a preparation method and application thereof.

Background technique

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Arsenic (As) is a highly toxic metal with strong teratogenic and carcinogenic effects, and its carcinogenicity is classified as Level 1 by the International Agency for Research on Cancer. Humans are exposed to arsenic through drinking water and the food chain, where arsenic accumulates in large amounts in the body's liver and kidney organs. Relevant pathological studies have found that long-term intake of drinking water or food with excessive arsenic content will cause chronic poisoning, that is, arsenic poisoning. Long-term exposure to high arsenic environment will make the human body susceptible to cancer. If the human body is exposed to a large amount of arsenic at one time, the conduction of the central nervous system will be blocked and the body will be numb, the respiratory tract and digestive tract will be diseased, and even death in severe cases of arsenic poisoning.

Arsenic-contaminated soil remediation technologies mainly include solidification/stabilization, soil leaching, heat treatment, phytoremediation and microbial remediation. Soil leaching is usually the addition of leaching agents (such as organic or inorganic acids, alkalis, salts and chelating agents) to the soil, which will not only destroy the soil microaggregate structure, but also lead to the leaching and precipitation of nutrients. And it is easy to cause secondary pollution problems such as groundwater pollution, which is suitable for soil treatment with small area and heavy pollution. Thermal treatment of arsenic-contaminated soil also damages soil structure, and also faces high treatment and operating costs. There are many cases of curing/stabilization applied to arsenic-contaminated soil, such as cement curing, chelating agent stabilization, iron and manganese oxides and other inorganic materials. Above 5%, it also faces problems such as high cost and easy generation of secondary pollution. Phytoremediation and microbial remediation have the advantages of low cost, no soil damage, and no secondary pollution, but they also have disadvantages such as low remediation efficiency and long remediation time.

The iron-manganese oxide has a loose structure, high surface charge, large specific surface area, abundant surface hydroxyl groups—OH, and has dual functions of oxidation and adsorption. The adsorption of arsenic on the iron oxide surface mainly belongs to the inner layer obligate adsorption. During the adsorption process, the hydroxyl group on the iron oxide surface undergoes ligand exchange and complexation reaction at the solid/liquid interface with arsenic(Ⅲ). However, since iron oxides cannot directly participate in the oxidation, their adsorption capacity is limited. Manganese oxides have certain oxidation and adsorption capacity for arsenic, arsenic (III) is adsorbed on the surface of manganese oxide, arsenic (III) on the surface can be oxidized to arsenic (V), and arsenic (V) is coordinated on the surface of manganese oxides reaction to form an arsenic(V)-MnO ₂ bidentate binuclear bridged complex. Compared with inorganic iron-manganese oxides, biological iron-manganese oxides have higher specific surface area and higher adsorption efficiency for arsenic.

Although the prior art has reported a method for remediating arsenic-contaminated soil with biological iron and manganese oxides, under the action of strain metabolites, the exchangeable arsenic in the soil can be converted into residual arsenic, thereby reducing the migration of arsenic in the soil. and bioavailability, effectively fixing arsenic in soil, but the inventors found that in the process of preparing biological iron and manganese oxides, bacterial growth is in a free state, and its oxidizing ability to divalent iron and manganese is limited, and the reaction products In a free state in an aqueous solution, it is difficult to collect naturally by precipitation. Therefore, its subsequent large-scale engineering application is limited.

SUMMARY OF THE INVENTION

In order to solve the deficiencies of the prior art, the present invention provides a diatomite-supported biological iron-manganese oxide material and a preparation method and application thereof. In the present invention, diatomite is used as a carrier, and divalent iron and divalent manganese are tightly adsorbed on the diatomite in the form of iron and manganese oxides through the action of strains, and the adsorption of diatomite as a carrier can effectively inhibit the reaction product. When the final diatomite-loaded biological iron-manganese oxide material is applied to the remediation of arsenic-contaminated soil, it can effectively convert the arsenic in the soil into a residual state, and achieve a significantly improved remediation effect.

In order to achieve the above purpose, a first aspect of the present invention provides a method for preparing a diatomite-loaded biological iron-manganese oxide material, specifically: inoculating a bacterial strain into a culture medium containing ferrous iron, divalent manganese and diatomite Culturing to obtain diatomite-loaded biological iron-manganese oxide material;

The strain is a strain capable of converting divalent iron and divalent manganese into iron and manganese oxides.

The second aspect of the present invention provides a diatomite-supported biological iron-manganese oxide material prepared by the above method.

A third aspect of the present invention provides a method for remediating arsenic-contaminated soil using the above-mentioned materials, specifically:

The diatomite-loaded biological iron-manganese oxide material is added to the arsenic-contaminated soil, and a series of physical-chemical reactions occur between the diatomite-loaded biological iron-manganese oxide material and trivalent arsenic or pentavalent arsenic in the soil, reducing The mobility of arsenic in soil can achieve the purpose of arsenic remediation.

One or more embodiments of the present invention have at least the following beneficial effects:

(1) The present invention uses diatomite as a carrier, and divalent iron and divalent manganese are tightly adsorbed on the diatomite in the form of iron-manganese oxide through the action of the bacterial strain, and the strong adsorption effect of the diatomite is utilized, and the bacteria can It can be fixed on diatomite to grow, improve the oxidation ability of bacteria to ferrous and manganese, and can effectively adsorb the reaction products on the surface of diatomite, prevent the reaction products from existing in free form, and accelerate the biological iron and manganese oxides. The efficiency of preparation and collection can effectively improve the remediation effect of arsenic-contaminated soil.

(2) The method has the advantages of simple process, short repair time, convenient operation, low treatment cost, large treatment range, and no secondary pollution.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

1 is a schematic diagram of the repairing effect of arsenic in Example 1;

2 is a schematic diagram of the repairing effect of arsenic in Example 2;

3 is a schematic diagram of the repairing effect of arsenic in Example 3;

4 is a schematic diagram of the repairing effect of arsenic in Example 4;

5 is a schematic diagram of the repairing effect of arsenic in Example 5;

6 is a schematic diagram of the repairing effect of arsenic in Example 6;

7 is a schematic diagram of the repairing effect of arsenic in Example 7;

8 is a schematic diagram of the repairing effect of arsenic in Example 8;

9 is a schematic diagram of the repairing effect of arsenic in Example 9;

10 is a schematic diagram of the repairing effect of arsenic in Example 10;

11 is a schematic diagram of the repairing effect of arsenic in Example 11;

12 is a schematic diagram of the repairing effect of arsenic in Example 12;

13 is a schematic diagram of the repairing effect of arsenic in Example 13;

14 is a schematic diagram of the repairing effect of arsenic in Example 14;

15 is a schematic diagram of the repairing effect of arsenic in Example 15;

16 is a schematic diagram of the repairing effect of arsenic in Example 16;

17 is a schematic diagram of the repairing effect of arsenic in Example 17;

18 is a schematic diagram of the repairing effect of arsenic in Example 18;

19 is a schematic diagram of the repairing effect of arsenic in Example 19;

20 is a schematic diagram of the repairing effect of arsenic in Example 20;

Figure 21 is a schematic diagram of the repairing effect of arsenic in Example 21;

22 is a schematic diagram of the repairing effect of arsenic in Example 22;

23 is a schematic diagram of the repairing effect of arsenic in Example 23;

Figure 24 is a schematic diagram of the repairing effect of arsenic in Example 24;

Figure 25 is a schematic diagram of the repairing effect of arsenic in Example 25;

Figure 26 is a schematic diagram of the repairing effect of arsenic in Example 26;

Figure 27 is a schematic diagram of the repairing effect of arsenic in Example 27;

Figure 28 is a schematic diagram of the repairing effect of arsenic in Example 28;

Figure 29 is a schematic diagram of the repairing effect of arsenic in Example 29;

30 is a schematic diagram of the repairing effect of arsenic in Example 30;

31 is a schematic diagram of the repairing effect of arsenic in Example 31;

32 is a schematic diagram of the repairing effect of arsenic in Example 32;

33 is a schematic diagram of the repairing effect of arsenic in Example 33;

34 is a schematic diagram of the repairing effect of arsenic in Example 34;

35 is a schematic diagram of the repairing effect of arsenic in Example 35;

FIG. 36 is a schematic diagram of the repairing effect of arsenic in Example 36. FIG.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

As described in the background art, in the prior art, only biological iron and manganese oxides are used to remediate arsenic-contaminated soil, although the migration and bioavailability of arsenic in soil can be reduced to a certain extent, and the arsenic in soil can be fixed. It is not significant, the main reason is: in the process of preparing biological iron and manganese oxides, the bacterial growth is in a free state, and its oxidizing ability to divalent iron and manganese is limited, and the reaction product is in a free state in an aqueous solution, which is difficult to naturally Precipitation collection, limit it for subsequent large-scale engineering applications.

In order to solve the above technical problems, a first aspect of the present invention provides a method for preparing a diatomite-loaded biological iron-manganese oxide material, specifically: inoculating a strain into a culture containing ferrous iron, divalent manganese and diatomite Cultivated in the base to obtain diatomite-loaded biological iron-manganese oxide material;

The bacterial strain is a bacterial strain capable of converting divalent iron and divalent manganese into iron-manganese oxides, preferably Pseudomonas putida strain MnB1.

Among them, the present invention introduces diatomite into the system because diatomite has a natural "molecular sieve"-like pore structure, a high specific surface area, which is 5000-6000 times that of activated carbon, and has strong adsorption performance. Soil as a carrier, bacteria can be fixed on diatomite to grow, improve the oxidation ability of bacteria to divalent iron and manganese, and in the process of bacterial iron and manganese oxidation, iron and manganese oxides can be adsorbed and fixed on the surface of diatomite, preventing iron and manganese. Manganese oxides exist in free form, which accelerates the preparation and collection efficiency of biological iron-manganese oxides, thereby effectively improving the arsenic restoration effect.

The reason why the present invention adopts the biological method of bacterial culture to convert diatomite, divalent iron and divalent manganese into iron-manganese oxide composite materials loaded on diatomite, rather than simply preparing by chemical oxidation The iron-manganese oxide composite material supported by diatomite is because the biological method has the following advantages compared with the conventional chemical reaction process: (1) The reaction conditions are milder, the environment is close to neutral, and a large amount of acid and alkaline reagents are avoided and the use of toxic and harmful reagents, the whole preparation process is more green and environmentally friendly; (2) Compared with inorganic iron-manganese oxides, biological iron-manganese oxides have higher specific surface area and higher adsorption efficiency for arsenic; (3) When the diatomite-loaded biological iron-manganese oxide material is used to treat arsenic-containing soil, it can realize the cyclic transformation of ferrous iron to ferric iron, and ferrous manganese to tetravalent manganese by means of the metabolic process of the strain, so that the material can be cyclically realized Remediation of Arsenic-Containing Soils.

In one or more embodiments of the present invention, the preparation method of the diatomite-supported biological iron-manganese oxide material specifically includes the following steps:

1) inoculate the bacterial strain in the medium for enrichment culture;

2) preparing a culture medium containing manganese;

3) adding ferrous iron, diatomite and enriched strains to the medium, shaking culture, centrifugal suction filtration to obtain diatomite-loaded biological iron-manganese oxide material.

Among them, ferrous manganese and ferrous iron were added to the medium in two steps, considering the characteristics of ferrous iron being easily oxidized, in order to avoid the change of its valence state, ferrous iron was added to the culture medium afterward.

In one or more embodiments of the present invention, the strain is Pseudomonas putida strain MnB1.

Specifically, the strain enrichment medium is a medium capable of enriching strains in the art, and the components of the medium can be adaptively adjusted for different types of strains; taking Pseudomonas putida as an example, as In a preferred embodiment, the culture medium is composed of: yeast extract powder 0.5-0.6g/L; acid hydrolyzed casein 0.5-0.6g/L; glucose 1-1.2g/L; calcium chloride dihydrate 0.29-0.3g/L ; Magnesium sulfate 0.82-0.84g/L; Ferric chloride 1-1.5ml/L; Trace elements 1-1.2ml/L; PH=7; 1.8-1.9g agar/100ml.

Further, the conditions of the enrichment culture are: at 15-35°C, under horizontal shaking (100-180rpm), aerobic enrichment culture for 1-5 days, under the culture conditions, the strains grow well.

Further, in the enrichment culture process, the transfer amount of the strain is 2-10%.

In one or more embodiments of the present invention, the medium containing divalent manganese is any medium supplemented with divalent manganese that can maintain the normal metabolism of the strain. As a preferred embodiment, the preparation method of the medium is as follows: : Take ferrous ammonium sulfate 0.15-0.18g/L, yeast extract powder 0.075-0.080g/L, sodium citrate 0.15-0.16g/L, sodium pyrophosphate 0.05g-0.08/L and manganese carbonate 1-1.2g/ L was prepared into a medium, 300 mL of medium was added to a 500 mL conical flask, pH was adjusted to 7, and 0.2 g/L of manganese carbonate was added at the same time.

Further, in order to avoid other strains from affecting the activity of the strains to be inoculated, and also to avoid by-products produced by the metabolism of other strains, sterilization treatment is performed after the configuration of the divalent manganese medium is completed, and then subsequent strains are inoculated, and the sterilization treatment time is: 30-40min, preferably 30min. The conditions of shaking culture are as follows: placing in a shaking incubator at 30-35° C. and 180-200 r·min ⁻¹ for shaking culture for 3-4 days.

Since ferrous iron, divalent manganese, strains, and diatomite have different effects and influence each other, the addition ratio has an important impact on the effect of arsenic-contaminated soil remediation. Among them, the conversion of ferrous iron to iron oxides, the adsorption of arsenic on its surface mainly belongs to the obligate adsorption of the inner layer. During the adsorption process, the hydroxyl groups on the surface of iron oxides form ligands at the solid/liquid interface with arsenic (III). Exchange and complexation reactions. The manganese oxide converted from divalent manganese has the ability to oxidize arsenic, arsenic (III) is adsorbed on the surface of manganese oxide, and the arsenic (III) on the surface can be oxidized to arsenic (V), and arsenic (V) occurs on the surface of manganese oxide. The coordination reaction results in the formation of an arsenic(V)-MnO ₂ bidentate binuclear bridged complex. If the addition amount of divalent iron is too high, the prepared materials will be mainly adsorbed on the surface, and the adsorption capacity will be unsatisfactory. However, if the addition amount of divalent manganese is too high, the whole process will be dominated by oxidation, the adsorption capacity will be reduced, and the arsenic will be reduced. It cannot be enriched on the surface of iron-manganese oxides, and it is also an efficient restoration without using arsenic-containing soil; therefore, as a preferred embodiment, the added mass ratio of divalent iron to divalent manganese is: 5:6;

Excessive addition of diatomite will reduce the proportion of active materials and weaken the arsenic soil remediation ability of diatomite-supported biological iron-manganese oxide materials, while too low addition of diatomite will lead to some tetravalent manganese. It cannot be adsorbed on the surface of diatomite, resulting in the release of tetravalent manganese, which will also reduce the repair effect. Preferably, the mass addition ratio of diatomite to divalent iron and divalent manganese is: 60-160:5:6. ;

The second aspect of the present invention provides a diatomite-loaded biological iron-manganese oxide material prepared by the above-mentioned method, the material includes strains and strains cultured in a medium containing divalent iron, divalent manganese and diatomite metabolite.

The diatomite-loaded biological iron-manganese oxide material is added to the arsenic-contaminated soil, and a series of physical-chemical reactions occur between the diatomite-loaded biological iron-manganese oxide material and trivalent arsenic or pentavalent arsenic in the soil, reducing The mobility of arsenic in soil to achieve the purpose of arsenic remediation;

Further, the diatomite-loaded biological iron-manganese oxide material is added to the arsenic-contaminated soil at a mass ratio of 1-5%, and the restoration effect is the best under this application amount;

Further, after the diatomite-loaded biological iron-manganese oxide material is added to the soil, the soil moisture content is adjusted to 20-60%, stirred with a mixer for 10-30 minutes, and then cultured at room temperature for 2-6 weeks; more Preferably, culturing for 2-6 weeks under aerobic/micro-aerobic conditions can better maintain the metabolic activity of the strain.

In order to enable those skilled in the art to understand the technical solutions of the present invention more clearly, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

Example 1

1) Enrichment culture of bacterial strains:

The selected bacterial strain was Pseudomonas putida strain MnB1, which was purchased from the American Type Culture Collection (ATCC). The bacteria were inoculated into Pseudomonas putida enrichment medium (yeast extract powder 0.5g/L; acid hydrolyzed casein 0.5g/L; glucose 1g/L; dihydrate Calcium chloride 0.29g/L; magnesium sulfate 0.82g/L; ferric chloride 1ml/L; trace elements 1ml/L; PH=7; -180rpm), aerobic enrichment culture for 1-5 days;

2) Preparation of diatomite-loaded biological iron-manganese oxide:

Preparation medium: ferrous ammonium sulfate (0.15g/L); yeast extract powder (0.075g/L); sodium citrate (0.15g/L); sodium pyrophosphate (0.05g/L) and manganese carbonate (1g/L) L), add 300 mL of culture medium to a 500 mL conical flask, and adjust pH=7. At the same time, 0.2g/L manganese carbonate was added. Sterilize for 30 minutes after configuration.

Prepare 500 mL of 500 mg/L FeCl ₂ solution, respectively add FeCl ₂ solution, diatomaceous earth (3 g) and strain to the sterilized medium. It was placed in a shaking incubator for 3 days with shaking at 180 r·min ^-1 (30°C). After the shaking is completed, the solid powder is obtained by centrifugal suction filtration, that is, the diatomite-supported biological iron-manganese oxide material.

3) Restoration process: adding the diatomite-loaded biological iron-manganese oxide material obtained in step (2) into the arsenic-contaminated soil for restoration work;

The diatomite-loaded biological iron-manganese oxide material prepared in step (2) was added to 30 grams of arsenic-contaminated soil according to the dosage ratio of 1% (0.3g), the soil moisture content was adjusted to 40%, and the mixer was stirred. The experiment was terminated after 20 minutes of incubation at room temperature (25°C) for 1 week.

As can be seen from accompanying drawing 1, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.258mg/L by 0.372mg/L when not repaired, The restoration efficiency was 30.6%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.386mg/L without restoration, and the restoration efficiency was 11.5%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.456mg/L, and its repair efficiency was 48.2%.

Example 2

On the basis of Example 1, the diatomite-loaded biological iron-manganese oxide material was set to 3% according to the dosage ratio;

As can be seen from accompanying drawing 2, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.211 mg/L from 0.372 mg/L when not repaired after water extraction, The restoration efficiency was 43.3%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.366mg/L without restoration, and the restoration efficiency was 16.1%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.491mg/L, and its repair efficiency was 44.2%.

Example 3

On the basis of Example 1, the diatomite-supported biological iron-manganese oxide material was set to 5% according to the dosage ratio;

As can be seen from accompanying drawing 3, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.228mg/L from 0.372mg/L when not repaired, The restoration efficiency was 38.7%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.342mg/L without restoration, and the restoration efficiency was 21.6%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.498mg/L, and its repair efficiency was 43.4%.

Example 4

On the basis of Example 1, the addition of diatomite was replaced by 5g;

As can be seen from accompanying drawing 4, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.258mg/L from 0.372mg/L when not repaired, The restoration efficiency was 30.6%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.384mg/L without restoration, and the restoration efficiency was 11.9%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.541mg/L, and its repair efficiency was 38.5%.

Example 5

On the basis of Example 4, the diatomite-loaded biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 5, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.255mg/L from 0.372mg/L when not repaired, The restoration efficiency was 31.5%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.373mg/L without restoration, and the restoration efficiency was 14.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.493mg/L, and its repair efficiency was 44.0%.

Example 6

On the basis of Example 4, the diatomite-loaded biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 6, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.239mg/L from 0.372mg/L when not repaired, The restoration efficiency was 35.6%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.336mg/L without restoration, and the restoration efficiency was 22.9%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.489mg/L, and its repair efficiency was 44.4%.

Example 7

On the basis of Example 1, the addition of diatomite was replaced by 8g;

As can be seen from accompanying drawing 7, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.255mg/L from 0.372mg/L when not repaired, The restoration efficiency was 31.5%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.345mg/L without restoration, and the restoration efficiency was 20.9%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.488mg/L, and its repair efficiency was 44.5%.

Example 8

On the basis of Example 7, the diatomite-loaded biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 8, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.241 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 35.2%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.360mg/L without restoration, and the restoration efficiency was 17.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.469mg/L, and its repair efficiency was 46.7%.

Example 9

On the basis of Example 7, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 9, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.239mg/L from 0.372mg/L when not repaired, The restoration efficiency was 35.6%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.347mg/L without restoration, and the restoration efficiency was 20.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.468mg/L, and its repair efficiency was 46.8%.

Example 10

On the basis of Example 1, the cultivation time in the soil remediation process was replaced by 2 weeks;

As can be seen from accompanying drawing 10, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.260 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 30.1%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.382mg/L without restoration, and the restoration efficiency was 12.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.435mg/L, and its repair efficiency was 50.6%.

Example 11

On the basis of Example 10, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 11, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.226 mg/L from 0.372 mg/L when not repaired, The repair efficiency was 39.2%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.354mg/L, and the repair efficiency was 18.8%; after sodium bicarbonate leaching, the arsenic content decreased significantly, from 0.880mg/L unrepaired L decreased to 0.435mg/L, and its repair efficiency was 50.6%.

Example 12

On the basis of Example 10, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 12, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.262 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 29.6%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.325mg/L without restoration, and the restoration efficiency was 25.5%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.469mg/L, and its repair efficiency was 46.7%.

Example 13

On the basis of Example 4, the cultivation time in the soil remediation process was replaced by 2 weeks;

As can be seen from accompanying drawing 13, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.274 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 26.3%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.351mg/L without restoration, and the restoration efficiency was 19.5%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.520mg/L, and its repair efficiency was 40.9%.

Example 14

On the basis of Example 13, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

It can be seen from accompanying drawing 14 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.260 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 30.1%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.321mg/L without restoration, and the restoration efficiency was 26.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.494mg/L, and its repair efficiency was 43.7%.

Example 15

On the basis of Example 13, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 15, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.259 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 30.4%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.327mg/L without restoration, and the restoration efficiency was 25.0%; the arsenic content decreased significantly after sodium bicarbonate leaching, from 0.880mg/L without restoration. L decreased to 0.515mg/L, and its repair efficiency was 41.5%.

Example 16

On the basis of Example 13, the addition of diatomaceous earth was replaced by 8g;

As can be seen from accompanying drawing 16, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.259 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 30.4%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.346mg/L without restoration, and the restoration efficiency was 20.6%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.514mg/L, and its repair efficiency was 41.6%.

Example 17

On the basis of Example 16, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 17, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.257mg/L from 0.372mg/L when not repaired, The restoration efficiency was 30.9%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.338mg/L without restoration, and the restoration efficiency was 22.5%; the arsenic content decreased significantly after sodium bicarbonate leaching, from 0.880mg/L without restoration. L decreased to 0.543mg/L, and its repair efficiency was 38.3%.

Example 18

On the basis of Example 16, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 18, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.257mg/L from 0.372mg/L when not repaired, The restoration efficiency was 30.9%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.337mg/L without restoration, and the restoration efficiency was 22.7%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.548mg/L, and its repair efficiency was 37.7%.

Example 19

On the basis of Example 1, the cultivation time in the soil remediation process was replaced by 3 weeks;

As can be seen from accompanying drawing 19, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and after water leaching, it is reduced to 0.235mg/L from 0.372mg/L when not repaired, The restoration efficiency was 36.8%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.321mg/L without restoration, and the restoration efficiency was 26.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.547mg/L, and its repair efficiency was 37.8%.

Example 20

On the basis of Example 19, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

It can be seen from accompanying drawing 20 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.225mg/L, the restoration efficiency was 39.5%; after TCLP leaching, it was reduced from 0.436mg/L unrepaired to 0.302mg/L, and the restoration efficiency was 30.7%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.542mg/L, and its repair efficiency was 38.4%.

Example 21

On the basis of Example 19, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 21, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and after water leaching, it is reduced to 0.229 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 38.4%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.296mg/L without restoration, and the restoration efficiency was 30.4%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.517mg/L, and its repair efficiency was 41.25%.

Example 22

On the basis of Example 13, the cultivation time in the soil remediation process was replaced by 3 weeks;

As can be seen from accompanying drawing 22, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.255mg/L from 0.372mg/L when not repaired, The restoration efficiency was 31.5%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.323mg/L without restoration, and the restoration efficiency was 25.9%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.537mg/L, and its repair efficiency was 39.0%.

Example 23

On the basis of Example 22, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 23, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.232mg/L from 0.372mg/L when not repaired, The restoration efficiency was 37.6%; after TCLP leaching, it decreased from 0.436mg/L to 0.294mg/L without restoration, and the restoration efficiency was 32.6%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.514mg/L, and its repair efficiency was 41.6%.

Example 24

On the basis of Example 22, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 24, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and after water extraction, it is reduced to 0.238 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 36.0%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.287mg/L without restoration, and the restoration efficiency was 34.2%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.487mg/L, and its repair efficiency was 44.7%.

Example 25

On the basis of Example 22, the addition of diatomaceous earth was replaced by 8g;

As can be seen from accompanying drawing 25, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and after water leaching, it is reduced to 0.251mg/L from 0.372mg/L when not repaired, The restoration efficiency was 32.5%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.311mg/L without restoration, and the restoration efficiency was 28.7%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.554mg/L, and its repair efficiency was 37.0%.

Example 26

On the basis of Example 25, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 26, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction, and the water extraction is reduced to 0.242 mg/L from 0.372 mg/L when not repaired, The restoration efficiency was 34.9%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.348mg/L without restoration, and the restoration efficiency was 20.2%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.553mg/L, and its repair efficiency was 37.2%.

Example 27

On the basis of Example 25, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 27, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.229mg/L, the repair efficiency was 38.4%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.288mg/L, and the repair efficiency was 33.9%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.557mg/L, and its repair efficiency was 36.7%.

Example 28

On the basis of Example 1, the cultivation time in the soil remediation process was replaced by 4 weeks;

As can be seen from accompanying drawing 28, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.237mg/L, the restoration efficiency was 36.3%; after TCLP leaching, the unrepaired 0.436mg/L decreased to 0.316mg/L, and the restoration efficiency was 27.5%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.605mg/L, and its repair efficiency was 31.25%.

Example 29

On the basis of Example 28, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

As can be seen from accompanying drawing 29, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.220mg/L, the restoration efficiency was 40.9%; after TCLP leaching, it was reduced from 0.436mg/L to 0.302mg/L without restoration, and the restoration efficiency was 30.7%; L decreased to 0.571mg/L, and its repair efficiency was 35.1%.

Example 30

On the basis of Example 28, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 30, the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.212mg/L, the restoration efficiency was 43.0%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.288mg/L, and the restoration efficiency was 33.9%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.557mg/L, and its repair efficiency was 36.7%.

Example 31

On the basis of Example 22, the cultivation time in the soil remediation process was replaced by 4 weeks;

It can be seen from accompanying drawing 21 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.226mg/L, the repairing efficiency was 39.2%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.311mg/L, and the repairing efficiency was 28.7%; L decreased to 0.551mg/L, and its repair efficiency was 37.4%.

Example 32

On the basis of Example 31, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

It can be seen from accompanying drawing 32 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.226mg/L, the restoration efficiency was 39.2%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.302mg/L, and the restoration efficiency was 30.7%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.563mg/L, and its repair efficiency was 36.0%.

Example 33

On the basis of Example 31, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

It can be seen from accompanying drawing 33 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.214mg/L, the repairing efficiency was 42.5%; after TCLP leaching, it decreased from 0.436mg/L unrepaired to 0.286mg/L, and the repairing efficiency was 34.4%; L decreased to 0.527mg/L, and its repair efficiency was 40.1%.

Example 34

On the basis of Example 25, the cultivation time in the soil remediation process was replaced by 4 weeks;

As can be seen from accompanying drawing 34, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.242mg/L from 0.372mg/L when not repaired, The restoration efficiency was 34.9%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.289mg/L without restoration, and the restoration efficiency was 33.7%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.561mg/L, and its repair efficiency was 36.25%.

Example 35

On the basis of Example 34, the diatomite-supported biological iron-manganese oxide material was replaced by 3% according to the dosage ratio;

It can be seen from accompanying drawing 35 that the arsenic content in the present embodiment is reduced by water extraction, TCLP extraction and sodium bicarbonate extraction. 0.221mg/L, the repair efficiency was 40.6%; after TCLP leaching, it decreased from unrepaired 0.436mg/L to 0.282mg/L, and the repair efficiency was 35.3%; after sodium bicarbonate leaching, the unrepaired 0.880mg/L L decreased to 0.540mg/L, and its repair efficiency was 38.6%.

Example 36

On the basis of Example 34, the diatomite-supported biological iron-manganese oxide material was replaced by 5% according to the dosage ratio;

As can be seen from accompanying drawing 36, the arsenic content in the present embodiment is reduced by water leaching, TCLP leaching and sodium bicarbonate leaching, and the water leaching is reduced to 0.224mg/L from 0.372mg/L when not repaired, The restoration efficiency was 39.8%; after TCLP leaching, the restoration efficiency decreased from 0.436mg/L to 0.268mg/L without restoration, and the restoration efficiency was 38.5%; the arsenic content decreased significantly after leaching with sodium bicarbonate, from 0.880mg/L without restoration. L decreased to 0.596mg/L, and its repair efficiency was 32.3%.

Comparative Example 1

On the basis of Example 11, no diatomaceous earth was added, and other conditions remained unchanged to obtain biological iron-manganese oxide.

Effectiveness analysis:

It can be seen from the above examples 1-36 that: using the diatomite-loaded biological iron-manganese oxide material provided by the present invention to treat the arsenic-containing soil, whether it is water leaching, TCLP leaching or sodium bicarbonate leaching, the arsenic The content of arsenic-contaminated soil is significantly reduced, which shows that the material can achieve excellent effect of remediation of arsenic-contaminated soil.

The arsenic stabilization efficiency of the biological iron-manganese oxide prepared in Comparative Example 1 and the diatomite-supported biological iron-manganese oxide prepared in Example 11 in water leaching and sodium bicarbonate leaching, respectively, is shown in Table 1. It can be seen that , the introduction of diatomite did lead to a better arsenic repair effect, mainly because the strong adsorption of diatomite enabled bacteria to grow on diatomite, and the reaction product could be effectively adsorbed on diatomite. On the surface, the reaction products are prevented from existing in a free state, and the preparation and collection efficiency of biological iron-manganese oxides are accelerated, thereby improving the arsenic restoration effect.

Table 1 Comparison of stabilization efficiency of arsenic

类型type	水浸提时(％)During water extraction (%)	碳酸氢钠浸提时(％)When leaching with sodium bicarbonate (%)
生物铁锰氧化物Biological iron manganese oxide	37.1837.18	43.2043.20
硅藻土负载型生物铁锰氧化物Diatomite-supported biological iron and manganese oxides	39.2039.20	50.6050.60

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

A method for preparing a diatomite-loaded biological iron-manganese oxide material, characterized in that: inoculating a bacterial strain into a culture medium containing ferrous iron, divalent manganese and diatomite to obtain diatomite-loaded biological iron-manganese oxide material;

The strain is a strain capable of converting divalent iron and divalent manganese into iron and manganese oxides.
preparation method as claimed in claim 1, is characterized in that: specifically comprises the following steps:

1) inoculate the bacterial strain in the medium for enrichment culture;

2) preparing a culture medium containing manganese;

3) adding ferrous iron, diatomite and enriched strains to the medium, shaking culture, centrifugal suction filtration to obtain diatomite-loaded biological iron-manganese oxide material.
The preparation method of claim 2, wherein the bacterial strain is Pseudomonas putidastrain MnB1.
The preparation method according to claim 2, characterized in that: the strain enrichment medium is composed of: yeast extract powder 0.5-0.6g/L; acid hydrolyzed casein 0.5-0.6g/L; glucose 1-1.2g/L ; calcium chloride dihydrate 0.29-0.3g/L; magnesium sulfate 0.82-0.84g/L; ferric chloride 1-1.5ml/L; trace elements 1-1.2ml/L; PH=7; 1.8-1.9g agar /100ml.
The preparation method of claim 2, wherein the enrichment culture conditions are: aerobic enrichment culture for 1-5 days at 15-35°C and horizontal shaking at 100-180rpm;

Preferably, in the enrichment culture process, the transfer amount of the strain is 2-10%.
The preparation method according to claim 2, characterized in that: the preparation method of the medium containing divalent manganese is as follows: taking 0.15-0.18g/L of ferrous ammonium sulfate, 0.075-0.080g/L of yeast extract, lemon Sodium 0.15-0.16g/L, sodium pyrophosphate 0.05g-0.08/L and manganese carbonate 1-1.2g/L were prepared into medium, 300mL medium was added to 500mL conical flask, pH=7 was adjusted, and the Add 0.2g/L manganese carbonate;

Preferably, the manganese medium is sterilized for 30-40 minutes after the preparation of the medium, and then inoculated with subsequent strains, more preferably 30 minutes.
The preparation method of claim 2, wherein the mass addition ratio of divalent iron, divalent manganese and diatomite is 60-160:5:6.
The preparation method of claim 2, wherein the shaking culture conditions are: shaking culture in a shaking incubator at 30-35°C and 180-200 r·min -1 for 3-4 days.
The diatomite-supported biological iron-manganese oxide material prepared by the method of any one of claims 1-8.
A method for repairing arsenic-contaminated soil using the material according to claim 9, specifically:

The diatomite-loaded biological iron-manganese oxide material is added to the arsenic-contaminated soil, and the diatomite-loaded biological iron-manganese oxide material has a physical-chemical reaction with trivalent arsenic or pentavalent arsenic in the soil;

Preferably, the diatomite-loaded biological iron-manganese oxide material is added to the arsenic-contaminated soil in a mass ratio of 1-5%;

Preferably, after the diatomite-loaded biological iron-manganese oxide material is added to the soil, the soil moisture content is adjusted to 20-60%, stirred with a mixer for 10-30 minutes, and then cultured at room temperature for 2-6 weeks;

More preferably, the culture is carried out under aerobic/microaerobic conditions for 2-6 weeks.