CN109570220B

CN109570220B - A method for bacteria-induced active iron-manganese oxides to remediate arsenic-contaminated soil under aerobic/micro-aerobic conditions

Info

Publication number: CN109570220B
Application number: CN201811435766.7A
Authority: CN
Inventors: 王华伟; 王亚楠; 孙英杰; 高莹
Original assignee: Qingdao University of Technology
Current assignee: Qingdao University of Technology
Priority date: 2018-11-28
Filing date: 2018-11-28
Publication date: 2021-08-03
Anticipated expiration: 2038-11-28
Also published as: CN109570220A; WO2020108214A1

Abstract

The invention relates to a method for bacteria-induced active iron and manganese oxides to repair arsenic-contaminated soil under aerobic/micro-aerobic conditions. The method selects Pseudomonas putida strain MnB1 (ATCC 23483), adds the strain Cultured in a medium containing manganese carbonate for 3-10 days until bacteria induced to produce brown-black flocculent products, and then the metabolites were added to arsenic-contaminated soil, and cultured under aerobic/micro-aerobic conditions for 3-21 days. Under the action of bacterial metabolites, exchangeable arsenic in soil can be converted into residual arsenic, which reduces the migration and bioavailability of arsenic in soil and effectively fixes arsenic in soil. The process is simple in operation, low in processing cost, wide in scope and free from secondary pollution.

Description

Method for restoring arsenic-polluted soil by bacteria-induced active iron manganese oxide under aerobic/microaerobic conditions

Technical Field

The invention belongs to the technical field of environment-friendly soil remediation treatment; relates to a method for restoring arsenic contaminated soil by bacteria induced active iron manganese oxide under aerobic/microaerobic conditions.

Technical Field

Arsenic (As) is a highly toxic metal that causes skin cancer, bladder cancer, and kidney disease, and poses serious threats to human health. Due to the large use of sewage irrigation, industrial sludge, arsenic-containing pesticides and the like in agricultural production, the soil is seriously polluted by arsenic. Research shows that the arsenic-polluted soil mainly contains inorganic trivalent arsenic and pentavalent arsenic, and in the soil environment, the toxic migration of the trivalent arsenic is higher than that of the pentavalent arsenic.

The arsenic contaminated soil remediation technology mainly comprises a physical-chemical remediation method, a plant remediation method and a microbial remediation method. The traditional physical-chemical remediation technology is usually large in dosage, high in cost, easy to generate secondary pollution and not suitable for remediation of large-area arsenic-polluted soil.

The phytoremediation technology is the most environment-friendly soil remediation technology, the remediation process is closer to natural ecology, the phytoremediation technology has the greatest advantage of purifying and beautifying the environment, and soil organic matters and fertility can be increased. The phytoremediation technology is suitable for the soil with large polluted area and slight pollution. And the investment of the plant restoration technology is low, the restoration period is short and no secondary pollution is caused. Research shows that most arsenic-enriched plants like yin and moisture, and the safe and practical dominant plants cannot be popularized in northern areas.

The microbial remediation effect of the arsenic-polluted soil is to change the biological effectiveness of arsenic through the biochemical reactions of oxidation reduction, adsorption, methylation, precipitation and the like of the arsenic by microbes, so as to achieve the purpose of remedying the arsenic-polluted soil. The microbial remediation technology of the arsenic-polluted soil mainly comprises two technologies: one is a bio-adsorption technique and the other is a bio-redox technique. The bioremediation technology is that the cell walls of various microorganisms such as bacteria, algae, fungi and the like have the capacity of combining with metal ions through the fixation of the cell walls of the microorganisms; even some microorganisms absorb arsenic, and the arsenic is used as a necessary nutrient element for growth and development. The biological oxidation-reduction technology is characterized in that microorganisms are utilized to change the ionic valence and activity of arsenic in the arsenic-polluted soil, so that the arsenic-polluted soil forms incompatible compounds, and therefore the purposes of reducing the toxicity of the arsenic in the soil and lightening the soil pollution are achieved. The main problems of the microbial remediation technology are that the arsenic remediation capability is very limited, and the arsenic is easy to migrate.

Disclosure of Invention

The invention aims to provide a method for restoring arsenic-polluted soil by bacteria-induced active iron-manganese oxides under aerobic/microaerobic conditions; the method comprises the following steps:

1) enrichment culture of bacterial strains:

pseudomonas putida is treatedP. putida Inoculating strain MnB1 into a Pseudomonas putida enrichment medium A according to the transfer amount of 5-10% of the volume ratio, and then performing aerobic enrichment culture for 1-5 days under the horizontal oscillation of 15-35 ℃ (100-; the components of the culture medium A comprise 0.3-0.8g of yeast extract powder, 0.2-0.8g of hydrolyzed casein, 0.3-0.8g of glucose, 0.1-0.4 g of calcium chloride, 0.1-0.6g of magnesium sulfate, 1-5 mL of trace elements and 1 liter of deionized water;

the selected bacterial strain is from American type bacteria Collection, and has a deposit number of ATCC 23483;

2) preparing active iron manganese oxide:

adding the pseudomonas putida bacterial liquid obtained by enrichment in the step 1) into a pseudomonas putida culture medium B with the pH of 6.5-7.5 according to the inoculation amount of 5-10% by volume ratio, simultaneously adding 0.2-1.8 g/L of manganese carbonate, and then culturing for 3-10 days at 15-35 ℃ under aerobic condition, wherein brownish black floccules appear in the culture medium, thus obtaining a bacterial metabolite;

the components of the culture medium B are 0.05-0.45 g of ammonium ferrous sulfate, 0.1-0.5g of sodium citrate, 0.01-0.3g of yeast extract powder, 0.01-0.05g of sodium pyrophosphate and 1 liter of deionized water;

3) repair process

Adding 20-80 mL of the bioactive iron-manganese oxide prepared in the step (2) into 50 g of arsenic-polluted soil, stirring for 5-30 minutes by using a stirrer, then placing the soil at room temperature (20-40 ℃), maintaining the soil at an aerobic/microaerobic condition, culturing for 3-21 days, allowing the bioactive iron-manganese oxide and trivalent arsenic or pentavalent arsenic in the soil to perform chemical reaction, and converting exchangeable arsenic into a residue state to be fixed in the soil so as to achieve a remediation effect.

Has the advantages that:

the invention relates to pseudomonas putida purchased by American mode strain collection centerP. putida strain MnB1, mixing with Pseudomonas putida culture medium B containing manganese carbonate according to the inoculum size of 5-10%, adjusting pH to 6.5-7.5, and culturing at 15-35 deg.C for 3-10 days to obtain active iron manganese oxide, which is a good soil remediation agent. The bioactive iron-manganese oxides are added into arsenic-polluted soil, and cultured for 3-21 days under aerobic/microaerobic conditions, so that exchangeable arsenic in the soil can be converted into residue, and the remediation effect is achieved.

The method selects pseudomonas putida capable of dissimilatorily oxidizing ferrous iron and manganesePseudomonas putida And (2) strain MnB1, carrying out enrichment culture on the strain in an enrichment culture medium, then inoculating the strain into a culture medium containing ferrous iron and manganese to culture to obtain metabolites, wherein the metabolites are mainly bioactive oxides rich in iron and manganese, then adding the bioactive iron and manganese oxides into arsenic-polluted soil, and terminating the experiment after culturing for several days under aerobic/microaerobic conditions. TheseThe biological active iron manganese oxide can effectively convert exchangeable arsenic into a residue state, thereby effectively fixing arsenic in soil and repairing arsenic pollution of the soil. The method has the advantages of simple process, convenient operation, low treatment cost, wide treatment range and no secondary pollution.

Drawings

FIG. 1: example 1 scanning electron microscopy of bacterially induced active iron manganese oxide;

FIG. 2: example 1 schematic representation of the change in water soluble arsenic content before and after remediation of active iron manganese oxides;

FIG. 3: example 1 a schematic diagram of the morphological change of arsenic before and after arsenic repair by active fe — mn oxide;

FIG. 4: example 2 schematic representation of water soluble arsenic content change before and after active iron manganese oxide repair;

FIG. 5: example 2 a schematic diagram of the morphological change of arsenic before and after arsenic repair by active iron manganese oxides;

FIG. 6: example 3 schematic representation of water soluble arsenic content change before and after active iron manganese oxide repair;

FIG. 7: example 3 a schematic diagram of the morphological changes of arsenic before and after arsenic repair by activated fe — mn oxide.

Detailed Description

The invention is further illustrated by the following experimental examples, without limiting the invention thereto.

Example 1

1) Enrichment culture of bacteria

The pseudomonas putida is treatedP. putida Inoculating strain MnB1 into a Pseudomonas putida enrichment medium A according to the transfer amount of 5% by volume, and then performing aerobic enrichment culture for 2 days under horizontal shaking (150 rpm) at 25 ℃;

the component of the culture medium A is yeast extract powder 0.5g, hydrolyzed casein 0.5g, glucose 0.5g, calcium chloride 0.29 g, magnesium sulfate0.5g, 1 mL of trace elements and 1 liter of deionized water;

the selected bacterial strain is from American type bacteria Collection ATCC with accession number ATCC 23483;

2) preparation of active metabolite:

adding the pseudomonas putida bacterial liquid enriched in the step 1) into a pseudomonas putida culture medium B containing manganese carbonate with the initial concentration of 1 g/L and the pH of 6.8 according to the inoculation amount of 6% of the volume ratio, and then culturing for 4 days at 25 ℃ under an aerobic condition, wherein the culture medium is brownish black, so that a bacterial metabolite is prepared;

the components of the culture medium B are 0.15g of ammonium ferrous sulfate, 0.15g of sodium citrate, 0.075g of yeast extract powder, 0.05g of sodium pyrophosphate and 1 liter of deionized water,

3) repair process

And (3) adding 50 mL of the active iron-manganese oxide prepared in the step (2) into 50 g of arsenic-polluted soil, stirring for 30 minutes by using a stirrer, then placing the mixture in a room temperature condition (25 ℃) for 15 days, allowing the active iron-manganese oxide and arsenic to perform chemical reaction, and converting exchangeable arsenic into a residue state so as to be fixed in the soil, thereby achieving a remediation effect.

The microstructure of the active ferromanganese oxide induced by bacteria is observed (figure 1), and the active ferromanganese oxide is mainly prepared by unreacted bacterial strains, manganese carbonate and amorphous or weak crystal form ferromanganese oxide mixture. As shown in the attached figure 2, when the ferro-manganese oxides are added into arsenic soil, the content of water-soluble arsenic is obviously reduced, and is reduced from 2.197 mg/kg when the iron-manganese oxides are not repaired to 0.715 mg/kg, and the repairing efficiency is 67.51 percent. Furthermore, the presence of arsenic in the soil was analyzed (FIG. 3), and the results showed that the percentage of exchangeable arsenic was 4.4% when unrepaired, and after remediation, the percentage of exchangeable arsenic was reduced to 0.94%, and the percentage of exchangeable arsenic in the residue was increased from 69.69% when unrepaired to 77.88%.

Example 2

1) Enrichment culture of bacterial strains:

pseudomonas putida is treatedP. putida Inoculating strain MnB1 into a Pseudomonas putida enrichment medium A according to the transfer amount of 10% of the volume ratio, and then performing aerobic enrichment culture for 5 days under horizontal shaking (150 rpm) at 25 ℃;

the components of the culture medium A comprise 0.5g of yeast extract powder, 0.5g of hydrolyzed casein, 0.5g of glucose, 0.2 g of calcium chloride, 0.3g of magnesium sulfate, 4mL of trace elements and 1 liter of deionized water;

2) preparing active iron manganese oxide:

adding the pseudomonas putida bacterial liquid obtained by enrichment in the step 1) into a pseudomonas putida culture medium B containing manganese carbonate with the initial concentration of 1.0g/L and the pH of 6.8 according to the inoculation amount of 10% of the volume ratio, and then culturing for 7 days at 30 ℃ under an aerobic condition to obtain brownish black floccules in the culture medium, thereby obtaining a bacterial metabolite;

the components of the culture medium B are 0.35g of ammonium ferrous sulfate, 0.25g of sodium citrate, 0.07g of yeast extract powder, 0.025g of sodium pyrophosphate and 1 liter of deionized water;

3) repair process

And (3) adding 20 mL of the bioactive iron-manganese oxide prepared in the step (2) into 50 g of arsenic-polluted soil, stirring for 10 minutes by using a stirrer, and then placing the mixture at room temperature (30 ℃) to culture the soil for 15 days under aerobic/microaerobic conditions. The content of water-soluble arsenic is obviously reduced from 2.197 mg/kg to 0.715 mg/kg when not repaired, and the repair efficiency is 67.51 percent (shown in figure 4). The morphological analysis of the presence of arsenic in the soil showed that the percentage of exchangeable arsenic was 4.4% when not remediated, decreased to 1.14% after remediation, and increased from 69.69% when not remediated to 75.88% when the residue was found (FIG. 5).

Embodiment 3

1) Enrichment culture of bacterial strains:

pseudomonas putida is treatedP. putida Inoculating strain MnB1 into a Pseudomonas putida enrichment medium A according to the transfer amount of 8% of the volume ratio, and then performing aerobic enrichment culture for 5 days under horizontal shaking (120 rpm) at 20 ℃;

the components of the culture medium B are 0.35g of yeast extract powder, 0.35g of hydrolyzed casein, 0.35g of glucose, 0.2 g of calcium chloride, 0.5g of magnesium sulfate, 2mL of trace elements and 1 liter of deionized water;

2) preparing active iron manganese oxide:

adding the pseudomonas putida bacterial liquid obtained by enrichment in the step 1) into a pseudomonas putida culture medium B containing manganese carbonate with the initial concentration of 1.0g/L and the pH of 7.0 according to the inoculation amount of 7% by volume, wherein the components of the culture medium are 0.25g of ammonium ferrous sulfate, 0.25g of sodium citrate, 0.23g of yeast extract powder, 0.02g of sodium pyrophosphate and 1 liter of deionized water, and then culturing for 4 days at 30 ℃ under an aerobic condition to obtain brownish black floccules in the culture medium, thereby obtaining a bacterial metabolite;

3) repair process

And (3) adding 40 mL of the bioactive iron-manganese oxide prepared in the step (2) into 50 g of arsenic-polluted soil, stirring for 10 minutes by using a stirrer, and then placing the mixture at room temperature (30 ℃) to culture the soil for 7 days under aerobic/microaerobic conditions.

The content of water-soluble arsenic is obviously reduced from 2.197 mg/kg to 0.60 mg/kg when not repaired, and the repair efficiency is 72.69 percent (figure 6). The analysis of the existing form of arsenic shows that the percentage of exchangeable arsenic is 4.4% when not repaired, and after repair, the percentage of exchangeable arsenic is reduced to 1.00%, and the percentage of exchangeable arsenic in the residue is increased from 69.69% when not repaired to 76.52% (FIG. 7).

As can be seen from the above embodiments: the method can achieve the effect of repairing the arsenic-polluted soil. Under aerobic conditions, pseudomonas putidaP. putida Strain MnB1 converts ferrous manganese in the medium into mixed metabolites of bacterial-ferro-manganese oxides, which are good soil remediation agents. When the metabolites are added into arsenic pollution, the migration and bioavailability of arsenic in soil can be effectively reduced, so that the arsenic in the soil can be fixed. The method has simple process and convenient operation. The treatment cost is low, no secondary pollution is caused, and the remediation of the arsenic-polluted soil can be realized.

Claims

1. under aerobic/micro-aerobic conditions, bacteria induces active iron manganese oxide to repair the method for arsenic-contaminated soil, it is characterized in that, in described arsenic-contaminated soil, be mainly based on inorganic trivalent arsenic and pentavalent arsenic, Proceed through the following steps:

1) Enrichment culture of bacterial strains:

The Pseudomonas putida strain MnB1 was inoculated into Pseudomonas putida enrichment medium A at a volume ratio of 5-10%, and then the aerobic enrichment culture was carried out under horizontal shaking at 15-35 degrees Celsius. For 1-5 days, the components of the medium A are yeast extract powder 0.3-0.8g, hydrolyzed casein 0.2-0.8g, glucose 0.3-0.8g, calcium chloride 0.1-0.4g, magnesium sulfate 0.1-0.6g, trace 1-5 mL of elements, 1 liter of deionized water;

2) Preparation of active iron manganese oxide:

Put the Pseudomonas putida bacterial solution enriched in step 1) into Pseudomonas putida culture medium B with an inoculum of 5-10% by volume with a pH of 6.5-7.5, and add 0.2-1.8 g/L at the same time The manganese carbonate is then cultivated at 15-35 degrees Celsius under aerobic conditions for 3-10 days, brown-black flocs are produced in the medium, that is, active iron and manganese oxides are obtained, and the composition of the medium B is sulfite Ferric ammonium 0.05-0.45g, sodium citrate 0.1-0.5g, yeast extract 0.01-0.3g, sodium pyrophosphate 0.01-0.05g, deionized water 1 liter;

3) Repair process

Add 20-80 mL of bioactive iron-manganese oxide prepared in step 2) to 50 g of arsenic-contaminated soil, stir with agitator for 5-30 minutes, and then place at room temperature to keep the soil aerobic/micro-aerobic Under conditions for 3-12 days, these active iron and manganese oxides will chemically react with trivalent arsenic or pentavalent arsenic in the soil, and the exchangeable arsenic in the soil will be changed into residual arsenic.

2. The method for bacteria-induced active iron-manganese oxides to repair arsenic-contaminated soil under aerobic/micro-aerobic conditions as claimed in claim 1, wherein the bacterial strain selected in step 1) comes from the American Model Bacteria Collection Center , deposit number ATCC23483.