CN106583431A - Bioremediation method for soil polluted by heavy metal lead cadmium and base on kosteletzkya virginica - Google Patents

Abstract

The invention discloses a bioremediation method for heavy metal lead and cadmium polluted soil based on seashore mallow, comprising the following steps: preparing mixed soil, preparing nutrient soil, preparing a nutrient bowl, pretreating seeds, sowing, transplanting, fertilizing and harvesting. The heavy metal lead and cadmium contaminated soil bioremediation method based on seashore mallow of the present invention can improve the survival rate of seashore mallow, and the seashore mallow grown is more robust, can efficiently absorb heavy metal lead and cadmium in the soil, and its effect on heavy metals The absorption rate of lead and cadmium is more than 70% higher than that of common cultivated seaside mallow.

Description

A bioremediation method for heavy metal lead and cadmium contaminated soil based on seashore mallow

technical field

The invention belongs to the technical field of heavy metal pollution restoration, and in particular relates to a bioremediation method for heavy metal lead and cadmium contaminated soil based on seaside mallow.

Background technique

Soil is an important resource for the survival and development of human society. However, with the rapid development of industrialization and the acceleration of urbanization, heavy metal pollution in my country's soil is becoming more and more serious. At present, lead and cadmium pollution is the most common type of soil heavy metal pollution, and its contaminated soil remediation is a difficult problem. The incubation period of heavy metal lead and cadmium pollution is long, and the harm is chronic accumulation, which is not easy to be noticed by people, and once the environment is polluted, the residual time is long, and it is not easy to remove from the environment.

Some physical or chemical methods currently used have a better remediation effect on soil with a small polluted area and a heavily polluted degree. However, physical or chemical remediation technologies are expensive, difficult to promote on a large scale, and are likely to damage the soil structure of the site, change the physical and chemical properties of the soil, and may cause secondary pollution. In addition, phytoremediation has attracted widespread attention due to its low cost, environmental friendliness, and effectiveness. However, the plants currently used for remediation of heavy metal-contaminated soils are short and slow-growing, and cannot form sufficient biomass in a short period of time, resulting in remediation cycles. Long, which limits the large-scale application of phytoremediation technology.

Seashore mallow (Kosteletzkya virginica) is a perennial herbaceous salt-tolerant economic plant, belonging to Malvaceae Seashore mallow, mainly distributed in subtropical, temperate and cold temperate saline swamps in North America. At present, there is no report on the application of seaside mallow and the remediation of heavy metal-contaminated soil, but compared with other plants used for the remediation of heavy metal-contaminated soil, seaside mallow is tall and has a short growth cycle, and can form larger plants in a short period of time. biomass, and exhibits strong resistance to salt and alkali, waterlogging, and heavy metal pollution. Therefore, try to apply it to the remediation of heavy metal-contaminated soil.

Contents of the invention

The present invention provides a bioremediation method for heavy metal lead and cadmium contaminated soil based on seaside mallow, which solves the problems of expensive, long repair period, easy damage to site structure, change of soil physical and chemical properties and problems caused by the existing heavy metal lead and cadmium contaminated soil repair technology. Bring the problem of secondary pollution.

The invention provides a method for bioremediation of heavy metal lead and cadmium contaminated soil based on seashore mallow, comprising the steps of:

Step 1, preparing mixed soil: crush river sand, humus soil and garden soil respectively, mix them evenly according to the mass ratio of 3:3:4, pass through a sieve with a mesh diameter of 2mm, and obtain mixed soil;

Step 2, preparing nutrient soil: add 25g of mycorrhizal agent and 20ml of phosphate solubilizing agent to every kilogram of mixed soil, and mix well to obtain nutrient soil;

Step 3, prepare the nutrient bowl: put the nutrient soil into a seedling raising pot with an outer diameter of 9cm and a height of 9cm to obtain a nutrient bowl;

Step 4, seed pretreatment: select seashore mallow seeds with plump grains and good seed coat color, soak them in water for two days, take them out, and set aside;

Step 5, sowing: sow the seaside mallow seeds soaked in step 4 in the nutrient bowl of step 3, cover with soil after sowing, and pour enough water, and when seaside mallow emerges and expands 2 true leaves, every 5 days Spray the EDTA solution with a concentration of 0.5mmol/L to the leaves once, and spray 3 times continuously;

Step 6, transplanting: when the height of seaside mallow seedlings reaches 15-20cm, take the seedlings together with the soil mass out of the nutrient pot, and transplant them into the soil polluted by lead and cadmium;

Step 7, fertilization: when seashore mallow seedlings are transplanted, apply mycorrhizal agent to the root soil of seashore mallow seedlings, and the application amount is 10-20g/plant, and then apply fertilizer to the seashore mallow roots once every 20-30 days, The application amount is 100-200g/plant, applied continuously for 3 times;

Wherein, the fertilizer is composed of the following components in parts by weight: 40-50 parts of ammonium nitrate, 10-20 parts of potassium dihydrogen phosphate, 10-20 parts of potassium lignosulfonate, 1-5 parts of seaweed element, 1-3 parts of EDTA-metal chelate, 1-3 parts of fulvic acid, 0.5-1 part of carboxymethyl cellulose, 0.5-1 part of sodium dodecylbenzenesulfonate, 0.5-1 Part of alkyl polyglucoside, 0.05-0.1 part of growth regulator;

Step 8, Harvesting: Harvest the part on the ground after the seaside mallow grows for 5-6 months;

Step 9, repeat steps 1 to 8, and continue to plant seaside mallow for bioremediation of heavy metal lead and cadmium contaminated soil.

Preferably, the mycorrhizal fungal agent is one or both of Glomus juveniles or Glomus moses.

Preferably, the phosphate-solubilizing bacteria agent is one or more of Bacillus megaterium, Pseudomonas and Rhizobium.

Preferably, the number of effective viable bacteria in the mycorrhizal agent is 1×10 ⁸ -2×10 ⁸ /g, and the effective number of viable bacteria in the phosphate-solubilizing agent is 3×10 ⁸ -4×10 ⁸ /mL.

Preferably, the covering soil thickness in step 5 is 0.5-1 cm.

Preferably, the EDTA-metal chelate is one or more of EDTA-Fe, EDTA-Ca, EDTA-Mg, and EDTA-Zn.

Preferably, the growth regulator is one or more of brassinolide, gibberellin, and naphthaleneacetic acid.

Compared with prior art, the beneficial effect of the present invention is:

1) The present invention sows seashore mallow by disposing nutrient soil in the nutrient bowl, improves the survival rate of seashore mallow on the one hand, makes seashore mallow grow more vigorously on the other hand, is conducive to absorbing heavy metal lead and cadmium.

2) the present invention is transplanted in the soil polluted by lead and cadmium after the seaside mallow is fertilized repeatedly to the root, and the ammonium nitrate, potassium dihydrogen phosphate, and potassium lignosulfonate contained in the fertilizer can provide the seaside mallow with its The nutrient elements nitrogen, phosphorus, and potassium required for growth, mycorrhizal agents can form symbiotic mycorrhizae with seaside mallow, enhance its ability to absorb lead and cadmium, and EDTA-metal chelates can reduce the stability of heavy metals in the soil. In order to enhance the absorption capacity of seaside mallow to heavy metals, fulvic acid can promote the absorption of nutrients by seaside mallow on the one hand, and keep the soil acidic on the other hand, which is beneficial to strengthen the absorption of lead and cadmium by seaside mallow.

detailed description

In order to enable those skilled in the art to better understand that the technical solutions of the present invention can be implemented, the present invention will be further described below in conjunction with specific examples, but the given examples are not intended to limit the present invention.

The strains used in the present invention were all purchased from the China Agricultural Microorganism Strain Preservation Management Center. The experimental methods described in the various embodiments of the present invention, unless otherwise specified, are conventional methods.

Example 1

A method for bioremediation of heavy metal lead and cadmium contaminated soil based on seaside mallow, comprising the steps of:

Step 1, preparing mixed soil: crush river sand, humus soil and garden soil respectively, mix them evenly according to the mass ratio of 3:3:4, pass through a sieve with a mesh diameter of 2mm, and obtain mixed soil;

Step 2, preparation of nutrient soil: add 25 g of young tunos mycotics with an effective viable count of 1×10 ⁸ /g and giant spores with an effective viable count of 3×10 ⁸ /mL to each kilogram of mixed soil Bacteria agent 20ml, mix evenly to get nutrient soil;

Step 3, prepare the nutrient bowl: put the nutrient soil into a seedling raising pot with an outer diameter of 9cm and a height of 9cm to obtain a nutrient bowl;

Step 4, seed pretreatment: select seashore mallow seeds with plump grains and good seed coat color, soak them in water for two days, take them out, and set aside;

Step 5, sowing: sow the seaside mallow seeds soaked in step 4 in the nutrient bowl of step 3, cover with soil 0.5cm after sowing, pour enough water, and when seaside mallow emerges and unfolds 2 true leaves, Spray the EDTA solution with a concentration of 0.5mmol/L to the leaves once every 5 days, and spray 3 times continuously;

Step 6, transplanting: when seaside mallow seedlings reach 15cm in height, take out the seedlings together with the soil mass from the nutrient pot, and transplant them into the soil polluted by lead and cadmium;

Step 7, fertilization: when seashore mallow seedlings are transplanted, apply effective viable count in the root soil of seashore mallow mallow seedlings and be 1 * ¹⁰ The young capsular mycotic agent of /g, application amount is 20g/ strain, then every Apply fertilizer once to the seaside mallow root in 20 days, the application amount is 200g/plant, apply continuously 3 times;

Wherein, the fertilizer is composed of the following components in parts by weight: 50 parts of ammonium nitrate, 15 parts of potassium dihydrogen phosphate, 10 parts of potassium lignosulfonate, 3 parts of seaweed, 2 parts of EDTA-Fe , 1 part of fulvic acid, 0.5 part of carboxymethylcellulose, 1 part of sodium dodecylbenzenesulfonate, 0.5 part of alkyl polyglucoside, 0.05 part of brassinolide;

Step 8, Harvesting: Harvest the part on the ground after the seaside mallow grows for 5 months;

Step 9, repeat steps 1 to 8, and continue to plant seaside mallow for bioremediation of heavy metal lead and cadmium contaminated soil.

Example 2

A method for bioremediation of heavy metal lead and cadmium contaminated soil based on seaside mallow, comprising the steps of:

Step 1, preparing mixed soil: crush river sand, humus soil and garden soil respectively, mix them evenly according to the mass ratio of 3:3:4, pass through a sieve with a mesh diameter of 2mm, and obtain mixed soil;

Step 2, preparation of nutrient soil: add 25g of young capsular mycotic agent with an effective viable count of 1.5× ¹⁰⁸ /g to each kilogram of mixed soil, and a fake form with an effective viable count of 3.5× ¹⁰⁸ /mL Bacteria agent 20ml, mix well to get nutrient soil;

Step 3, prepare the nutrient bowl: put the nutrient soil into a seedling raising pot with an outer diameter of 9cm and a height of 9cm to obtain a nutrient bowl;

Step 4, seed pretreatment: select seashore mallow seeds with plump grains and good seed coat color, soak them in water for two days, take them out, and set aside;

Step 5, sowing: Sow the seaside mallow seeds soaked in step 4 in the nutrient bowl of step 3, cover with soil 1cm after sowing, and pour enough water. Spray the EDTA solution with a concentration of 0.5mmol/L once a day to the leaves, and spray 3 times continuously;

Step 6, transplanting: when seaside mallow seedlings reach 18cm in height, take out the seedlings together with the soil mass from the nutrient pot, and transplant them into the soil polluted by lead and cadmium;

Step 7, fertilization: when the seaside mallow seedlings are transplanted, apply the young capsule mycotic agent to the soil of the seaside mallow seedlings' roots, the application amount is 15g/plant, and then apply the fertilizer to the seaside mallow roots once every 25 days, and the application amount 150g/plant, applied 3 times continuously;

Wherein, the fertilizer is composed of the following components in parts by weight: 45 parts of ammonium nitrate, 20 parts of potassium dihydrogen phosphate, 15 parts of potassium lignosulfonate, 5 parts of seaweed, 3 parts of EDTA-Ca , 3 parts of fulvic acid, 1 part of carboxymethyl cellulose, 0.5 part of sodium dodecylbenzenesulfonate, 1 part of alkyl polyglucoside, 0.1 part of gibberellin;

Step 8, Harvesting: Harvest the part on the ground when the seaside mallow grows for 6 months;

Step 9, repeat steps 1 to 8, and continue to plant seaside mallow for bioremediation of heavy metal lead and cadmium contaminated soil.

Example 3

A method for bioremediation of heavy metal lead and cadmium contaminated soil based on seaside mallow, comprising the steps of:

Step 1, preparing mixed soil: crush river sand, humus soil and garden soil respectively, mix them evenly according to the mass ratio of 3:3:4, pass through a sieve with a mesh diameter of 2mm, and obtain mixed soil;

Step 2, preparation of nutrient soil: Add ²⁵ g of Moses Globulus mycotic agent with an effective viable count of 2×108/g and a rhizobium agent with an effective viable count of ⁴ ×108/mL to each kilogram of mixed soil 20ml, mix well to get nutrient soil;

Step 3, prepare the nutrient bowl: put the nutrient soil into a seedling raising pot with an outer diameter of 9cm and a height of 9cm to obtain a nutrient bowl;

Step 4, seed pretreatment: select seashore mallow seeds with plump grains and good seed coat color, soak them in water for two days, take them out, and set aside;

Step 5, sowing: Sow the seaside mallow seeds soaked in step 4 in the nutrient bowl of step 3, cover with soil 0.8cm after sowing, pour enough water, and when seaside mallow emerges and expands 2 true leaves, Spray the EDTA solution with a concentration of 0.5mmol/L to the leaves once every 5 days, and spray 3 times continuously;

Step 6, transplanting: when seaside mallow seedlings reach 20cm in height, take out the seedlings together with the soil mass from the nutrient pot, and transplant them into the soil polluted by lead and cadmium;

Step 7, fertilization: when the seaside mallow seedlings are transplanted, apply the Moses balloon fungal agent to the seashore mallow seedling root soil, and the application amount is 10g/plant, and then apply fertilizer once to the seaside mallow roots every 30 days, and the application amount is 100g/plant, applied 3 times continuously;

Wherein, the fertilizer is composed of the following components in parts by weight: 40 parts of ammonium nitrate, 20 parts of potassium dihydrogen phosphate, 20 parts of potassium lignosulfonate, 1 part of seaweed, 1 part of EDTA-Mg , 2 parts of fulvic acid, 1 part of carboxymethyl cellulose, 1 part of sodium dodecylbenzenesulfonate, 1 part of alkyl polyglucoside, 0.08 part of naphthaleneacetic acid;

Step 8, Harvesting: Harvest the part on the ground when the seaside mallow grows for 6 months;

Step 9, repeat steps 1 to 8, and continue to plant seaside mallow for bioremediation of heavy metal lead and cadmium contaminated soil.

The seashore mallow that the method that embodiment 1-3 adopts is planted all can carry out good absorption to heavy metal lead, cadmium in the soil, detects lead, cadmium concentration in the seashore mallow that harvests after planting and harvesting for the first time, The specific experimental results are as follows:

Table 1 Concentrations of lead and cadmium absorbed in seaside mallow

Cadmium content in seaside mallow (mg/kg) Lead content in seaside mallow (mg/kg) Example 1 163.36 630.93 Example 2 175.44 658.32 Example 3 181.52 703.13

Embodiment 1-3 all is after seashore mallow harvests, cuts the ground part along the soil surface, weighs dry weight after drying at 105 ℃, digests with nitric acid-perchloric acid method then, adopts ICP to measure lead, concentration of cadmium. As can be seen from Table 1, the seashore mallow planted by the inventive method all has good absorption to the heavy metal lead and cadmium in the polluted soil, and after the growth period of 5-6 months, the seashore mallow has good absorption to the heavy metal lead and cadmium in the soil. The absorption of cadmium can reach more than 160mg/kg, and the absorption of lead can reach more than 630mg/kg. Compared with the prior art, the absorption rate is increased by more than 70%.

The present invention configures nutrient soil and puts the nutrient soil into a seedling pot to form a nutrient bowl to sow seaside mallow, so that the survival rate of seaside mallow reaches 100%, which is far superior to the traditional method of directly sowing seaside mallow on polluted land The survival rate of sunflower (about 70%), and because seashore mallow has provided enough nutrition at the seed stage and seedling stage, seashore mallow grows more vigorously, and has the ability to absorb heavy metal lead and cadmium.

In the present invention, after the seaside mallow is transplanted into the soil polluted by lead and cadmium, fertilization is applied to the roots for many times, and the ammonium nitrate, potassium dihydrogen phosphate, and potassium lignosulfonate contained in the fertilizer can provide seaside mallow with the necessary nutrients for its growth. The nutrients needed are nitrogen, phosphorus, and potassium. At the same time, potassium lignosulfonate can also improve soil structure, loosen soil, improve soil fertility, adjust pH, reduce heavy metal content in soil, and reduce the impact of salt ions on seashore mallow seedlings. harm; mycorrhizal agents can form symbiotic mycorrhizae with seaside mallow, enhance their ability to absorb lead and cadmium, and EDTA-metal chelates can reduce the stability of heavy metals in soil, thereby enhancing seaside mallow’s ability to absorb heavy metals On the one hand, fulvic acid can promote the absorption of nutrient elements by seaside mallow, on the other hand, it can keep the soil acidic, which is beneficial to strengthen the absorption of lead and cadmium by seaside mallow; , to maintain the acidity of the soil, on the other hand, it can promote plant cell division and increase the growth of seaside mallow rhizomes; sodium dodecylbenzenesulfonate is an anionic surface active group, and alkyl polyglucoside is a nonionic surface active group The active group, the two can act synergistically to reduce the surface tension of the soil, so that heavy metals are more conducive to complexation or to be absorbed by the root system of sea mallow. Cluster interaction, thereby changing the structure and permeability of cell membranes, and promoting the absorption of heavy metals by plants.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, it is also intended to include these modifications and variations.

Claims (7)

1. a kind of heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica, it is characterised in that including following step Suddenly：

Step 1, prepares composite soil：According to 3 after river sand, peat, garden mould are smashed to pieces respectively：3：4 quality is than mix homogeneously, mistake Mesh diameter is the sieve of 2mm, obtains composite soil；

Step 2, prepares Nutrition Soil：Add 25g bush mycorrhiza agents, 20ml phosphorus decomposing microbial inoculums toward every kilogram of composite soil, mix homogeneously is obtained To Nutrition Soil；

Step 3, prepares nutritive cube：Nutrition Soil is loaded into external diameter 9cm, in the pot for growing seedlings of high 9cm, nutritive cube is obtained；

Step 4, Seeds preprocess：The good Kosteletzkya virginica seed of full seed, Seed colour is selected, it is soaked two days in water After take out, it is standby；

Step 5, sowing：Kosteletzkya virginica seed after soaking in step 4 is seeded in the nutritive cube of step 3, after sowing is finished Earthing, drenches sufficient moisture, when Kosteletzkya virginica is emerged and launches 2 true leaves, per 5 days toward leaf surface spraying concentration for 0.5mmol/L's EDTA solution once, continuously sprays 3 times；

Step 6, transplants：When Kosteletzkya virginica seedling height of seedling reaches 15-20cm, the related mass of soil of seedling is taken out from nutritive cube, It is transplanted to by lead, the soil of cadmium pollution；

Step 7, fertilising：Apply bush mycorrhiza agent, applied amount toward in Kosteletzkya virginica seedling root soil during Kosteletzkya virginica seedling replanting For 10-20g/ strains, then applied fertilizer once toward Kosteletzkya virginica root per 20-30 days, applied amount is 100-200g/ strains, continuously Apply 3 times；

Wherein, the fertilizer is made up of the component of following parts by weight：The ammonium nitrate of 40-50 parts, the biphosphate of 10-20 parts Potassium, the lignin sulfonic acid potassium of 10-20 parts, the seaweeds of 1-5 parts, the EDTA- metallo-chelates of 1-3 parts, the fulvic acid of 1-3 parts, The carboxymethyl cellulose of 0.5-1 parts, the dodecylbenzene sodium sulfonate of 0.5-1 parts, the alkyl polyglucoside of 0.5-1 parts, 0.05- 0.1 part of growth regulator；

Step 8, harvesting：After Kosteletzkya virginica grows 5-6 month, the part on ground is gathered in；

Step 9,1～step 8 of repeat step, continuing plantation Kosteletzkya virginica heavy metal lead cadmium pollution soil carries out biological restoration.

2. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature It is that the bush mycorrhiza agent is Glomus etunicatum bacterium (Glomus etunicatum) or Glomus mosseae bacterium (Glomus Mosseae one or two in).

3. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature It is that the phosphorus decomposing microbial inoculum is bacillus megaterium (Bacillus megaterium), Pseudomonas alba (Pseudomonadaceae), one or more in root nodule bacteria (Root nodule bacteria).

4. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature It is that living bacteria count is 1 × 10 in the bush mycorrhiza agent⁸-2×10⁸Individual/g, in the phosphorus decomposing microbial inoculum living bacteria count be 3 × 10⁸-4×10⁸Individual/mL.

5. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature It is that thickness of earth covering is 0.5-1cm in the step 5.

6. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature Be, the EDTA- metallo-chelates be EDTA-Fe, EDTA-Ca, EDTA-Mg, one or more in EDTA-Zn.

7. the heavy metal lead cadmium pollution soil biological renovation method based on Kosteletzkya virginica according to claim 1, its feature It is that the growth regulator is one or more in brassin lactones, gibberellins, naphthalene acetic acid.