Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a combined remediation method of copper-polluted soil, which aims to convert insoluble or weak acid salt combined state in the polluted soil into exchangeable copper ions which are easy to absorb by plants by utilizing the activation effect of microorganisms, enrich heavy metals in the plants through the growth and propagation of the plants, remove the heavy metals, remarkably reduce the content of the heavy metals in the copper-polluted soil and be used for remediation of copper-polluted soil areas with different degrees.
In order to achieve the purpose, the invention provides the following technical scheme:
a combined remediation method of copper-contaminated soil comprises the following steps:
adding the microbial inoculum into copper-polluted soil according to the application amount of 25-45 kg/mu and uniformly turning;
planting the arthrodia grassland in the soil polluted by the copper containing the microbial agent, and removing the copper in the soil by utilizing the activation effect of the microbial agent and the absorption and enrichment of the arthrodia grassland on the copper;
wherein the microbial agent is mixed spore powder of penicillium oxalicum and yellow-blue fungi.
Preferably, the preparation method of the penicillium oxalicum and yellow blueish mixed spore powder comprises the following steps:
1) slant culture
Respectively inoculating original strains of penicillium oxalicum and yellow bluefungus on a slant culture medium under the aseptic condition, and culturing for 48-72 hours at the temperature of 26-28 ℃;
2) shaking table cultivation
Adding sterile water to the slant of the strain cultured in the step 1), scraping spores, and diluting to obtain the product with spore content of 1 × 106-1×107cfu/mL spore suspension is respectively inoculated in a seed culture medium under aseptic condition and cultured for 18-24 hours in a shaking table at 140-160r/min under the conditions of pH6.0-6.5 and temperature of 26-28 ℃;
3) cultivation in fermenter
Inoculating the strain cultured in the step 2) into a liquid fermentation culture medium in an inoculation amount of 15-18% by volume under aseptic conditions, and stopping fermentation when the produced mycelium accounts for 20% of the total volume after culturing for 72-96 hours under the conditions of pH6.0-7.0, tank pressure of 0.05-0.06 MPa, temperature of 26-28 ℃ and ventilation amount of 1: 0.6-0.8 vvm;
4) solid fermentation spore production
Inoculating the mycelium cultured in the step 3) to a solid fermentation culture medium, culturing for 168-180 hours, and stopping fermentation to obtain a mixed solid fermentation product;
5) drying and crushing the solid fermentation product obtained in the step 4) to prepare the mixed spore powder of the penicillium oxalicum and the yellow blueness bacteria.
Further, the formula of the slant culture medium is as follows: 20g/L of glucose, 200g/L of potato juice and 20g/L of agar.
Preferably, the formulation of the seed culture medium is 20-25g/L of sucrose, 5-7g/L of peptone, 0.2-0.3g/L of monopotassium phosphate, 0.2-0.3g/L of magnesium sulfate and 2-4g/L of sodium chloride.
Preferably, the formula of the liquid fermentation medium is as follows: 20-25g/L of starch, 5-6g/L of corn flour, 2-3g/L of bean cake powder, 20-25g/L of cane sugar, 5-6g/L of peptone, 0.2-0.3g/L of magnesium sulfate, 20-25g/L of sodium chloride and 0.05-0.08% of defoaming agent (v/v).
Preferably, the solid fermentation medium formula is as follows: mixing rice straw, corn flour and chaff according to the weight ratio of 7:2:1 to form a solid material, and adding water into the solid material for mixing to obtain a solid fermentation culture medium; wherein the weight ratio of the solid material to the water is 1: 0.6-0.65.
Preferably, the method also comprises the step of carrying out periodic harvesting after the planting of the Equisetum ramosissimum; the harvesting occurs when the Equisetum ramosissimum grows for 18-22 knots, and the harvesting method comprises the following steps: harvesting 5-10cm away from the root of the Equisetum ramosissimum, and separating and extracting heavy metal copper enriched in the plant body by adopting a hydrothermal liquefaction method.
The scheme of the invention has the following beneficial effects:
the invention provides a combined remediation method for copper-contaminated soil, which jointly removes copper in the soil by utilizing the activation of a microbial agent and the absorption and enrichment of the herba arthrodii for the copper, has simple operation mode and low cost, and is suitable for remediation of copper-contaminated areas.
In the combined remediation method for the copper-contaminated soil, the adopted strains of penicillium oxalicum and ceruleus flavus can tolerate heavy metal copper and have acid production characteristics, weak acid binding state copper in the contaminated soil is further activated through the synergy of the acid production functions of the two strains, so that the weak acid binding state copper is converted into an ionic state or an exchangeable state, copper is enriched through the growth and propagation of the arthrodia, and plants are further harvested for post-treatment to achieve the purpose of removing the heavy metal copper; in addition, a mixed solid fermentation method is adopted in the preparation process of the spore powder, so that the operation steps are simplified, and the time resource is saved.
Thirdly, in the combined remediation method for the copper-contaminated soil, the Equisetum ramosissimum is a perennial plant, and the effect of gradually removing the heavy metal copper can be achieved by planting once and periodically harvesting for many years, so that resources are saved; the microorganism-plant combined remediation method is simple and easy to operate, environment-friendly and low in consumption, can remarkably reduce the content of heavy metals in copper-polluted soil, and can be used for remediation of copper-polluted soil areas with different degrees.
Detailed Description
In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following detailed description is given with reference to specific embodiments.
Example 1
The method specifically comprises the following steps:
step one, adding the microbial inoculum to copper-polluted soil according to the application amount of 35 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial inoculum in a polluted area;
the preparation method of the microbial agent comprises the following specific steps:
1) slant culture: respectively selecting 1 ring of original strains of penicillium oxalicum and yellow bluefungi under the aseptic condition, respectively inoculating the strains on a slant culture medium, and culturing for 72 hours at the temperature of 28 ℃; wherein, the formula of the slant culture medium is as follows: 20g/L of glucose, 200g/L of potato juice and 20g/L of agar, and the pH is natural;
2) shake cultivation: adding sterile water to the slant of the strain cultured in the step 1), scraping spores, and diluting to obtain the product with spore content of 1 × 107cfu/mL spore suspension is respectively inoculated in a seed culture medium under aseptic condition and cultured for 24 hours at 140r/min by a shaking table under the conditions of pH6.0-6.5 and 28 ℃; wherein, the formula of the seed culture medium is as follows: 20g/L of sucrose, 5g/L of peptone, 0.2g/L of monopotassium phosphate, 0.2g/L of magnesium sulfate and 2g/L of sodium chloride;
3) culturing in a fermentation tank: inoculating the strain cultured in the step (2) into a liquid fermentation culture medium in an inoculation amount of 15% by volume under aseptic conditions, and stopping fermentation when the produced mycelium accounts for 20% of the total volume after culturing for 72 hours under the conditions of pH6.0, tank pressure of 0.05MPa, temperature of 28 ℃ and ventilation quantity of 1:0.6 vvm; wherein the formula of the liquid fermentation medium is as follows: 20g/L of starch, 6g/L of corn flour, 2g/L of bean cake powder, 20g/L of cane sugar, 6g/L of peptone, 0.2g/L of magnesium sulfate, 25g/L of sodium chloride and 0.08% of defoaming agent.
4) Solid fermentation spore production: inoculating the mycelium cultured in the fermentation tank in the step 3) to a solid fermentation culture medium, culturing for 168 hours, and stopping fermentation; wherein the formula of the solid fermentation medium is as follows: adding water into a solid material formed by mixing rice straws, corn flour and chaff according to the weight ratio of 7:2:1 to obtain a solid fermentation culture medium, wherein the weight ratio of the solid material to the water is 1: 0.6;
5) drying and crushing the mixed solid fermentation product obtained in the step 4) to prepare penicillium oxalicum and yellow blueness bacterium mixed spore powder;
planting a plant with copper enrichment capacity, namely the Equisetum ramosissimum in the copper polluted area, and performing plant division propagation in a propagation mode, wherein the planting density is 12 plants/m2。
Harvesting 18-22 knots of the arthrolicus to remove heavy metal copper at a position 5-10cm away from the root of the plant, and separating and extracting the heavy metal copper enriched in the plant body by adopting a hydrothermal liquefaction method;
in the implementation process of the method, the content change of heavy metal copper in the polluted soil is determined after the Equisetum ramosissimum is harvested.
Example 2
The method specifically comprises the following steps:
step one, adding the microbial inoculum to copper-polluted soil according to the application amount of 35 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial inoculum in a polluted area;
the preparation method of the microbial agent comprises the following specific steps:
1) slant culture: respectively selecting 1 ring of original strains of penicillium oxalicum and yellow bluefungi under the aseptic condition, respectively inoculating the strains on a slant culture medium, and culturing for 48 hours at the temperature of 26 ℃; wherein, the formula of the slant culture medium is as follows: 20g/L of glucose, 200g/L of potato juice and 20g/L of agar, and the pH is natural;
2) shake cultivation: adding sterile water to the slant of the strain cultured in the step 1) to scrape spores, and diluting the spores to 1 x 106cfu/mL spore suspension is respectively inoculated in a seed culture medium under aseptic condition and cultured for 18 hours in a shaking table at 160r/min under the conditions of pH6.0-6.5 and 26 ℃; wherein the formula (g/L) of the seed culture medium is as follows: 25g/L of sucrose, 7g/L of peptone, 0.3g/L of monopotassium phosphate, 0.3g/L of magnesium sulfate and 4g/L of sodium chloride;
3) culturing in a fermentation tank: inoculating the strain cultured in the step (2) into a liquid fermentation culture medium in an inoculation amount of 18% by volume under aseptic conditions, and stopping fermentation when the produced mycelium accounts for 20% of the total volume after 96 hours of culture under the conditions of pH7.0, tank pressure of 0.06MPa, temperature of 26 ℃ and ventilation quantity of 1:0.8 vvm; wherein the formula of the liquid fermentation medium is as follows: 25g/L of starch, 5g/L of corn flour, 3g/L of bean cake powder, 25g/L of cane sugar, 5g/L of peptone, 0.3g/L of magnesium sulfate, 20g/L of sodium chloride and 0.05% of defoaming agent (v/v).
4) Solid fermentation spore production: inoculating the mycelium cultured in the fermentation tank in the step 3) to a solid fermentation culture medium, culturing for 180 hours, and stopping fermentation; wherein the formula of the solid fermentation medium is as follows: adding water into a solid material formed by mixing rice straws, corn flour and chaff according to the weight ratio of 7:2:1 to obtain a solid fermentation culture medium, wherein the weight ratio of the solid material to the water is 1: 0.65;
5) drying and crushing the mixed solid fermentation product obtained in the step 4) to prepare penicillium oxalicum and yellow blueness bacterium mixed spore powder;
the rest of the procedure was the same as in example 1.
In the implementation process of the method, the content change of heavy metal copper in the polluted soil is determined after the Equisetum ramosissimum is harvested.
Example 3
The method specifically comprises the following steps:
step one, adding the microbial inoculum to copper-polluted soil according to the application amount of 30 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial inoculum in a polluted area;
the rest of the procedure was the same as in example 1.
Example 4
The method specifically comprises the following steps:
step one, adding the microbial inoculum to copper-polluted soil according to the application amount of 40 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial inoculum in a polluted area;
the rest of the procedure was the same as in example 1.
Example 5
The method specifically comprises the following steps:
step one, adding the microbial inoculum to copper-polluted soil according to the application amount of 45 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial inoculum in a polluted area;
the rest of the procedure was the same as in example 1.
Example 6
The method specifically comprises the following steps:
the planting density of the Equisetum ramosissimum in the second step in example 1 was adjusted to 9 plants/m2。
The rest of the procedure was the same as in example 1.
Example 7
The method specifically comprises the following steps:
the planting density of the arthroncus nodiflora in the second step in the example 1 is adjusted to 15 plants/m2。
The rest of the procedure was the same as in example 1.
Example 8
The method specifically comprises the following steps:
step one, adding single-bacterium agent penicillium oxalicum spore powder to copper-polluted soil according to the application amount of 35 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial agent in a polluted area;
the rest of the procedure was the same as in example 1.
Example 9
The method specifically comprises the following steps:
step one, adding single microbial agent of bluish yellow spore powder to copper-polluted soil according to the application amount of 35 kg/mu, and uniformly turning by using mechanical equipment such as a turning machine and the like to uniformly distribute the microbial agent in a polluted area;
the rest of the procedure was the same as in example 1.
The results of remediation of soil contaminated with copper according to the methods described in examples 1 to 9 were shown in the following table, with only the treatment of Arthropoda japonica planted without any remediation treatment (control 1) and without any microbial agent (control 2).
Processing groups
|
Initial effective copper content (mg/kg)
|
Post harvest effective copper content (mg/kg)
|
Control group 1
|
412.23
|
412.12
|
Control group 2
|
413.01
|
401.26
|
Example 1
|
413.25
|
375.59
|
Example 2
|
414.03
|
376.23
|
Example 3
|
413.21
|
391.21
|
Example 4
|
414.37
|
381.56
|
Example 5
|
412.98
|
394.48
|
Example 6
|
413.13
|
377.27
|
Example 7
|
413.45
|
378.11
|
Example 8
|
412.99
|
394.34
|
Example 9
|
413.00
|
395.19 |
As can be seen from the data analysis in the table, the effective copper content in the contaminated soil can be reduced to different degrees by adopting the methods described in the examples 1 to 9, and the combined remediation effect of the microbial agent and the arthroncus is better than that of the control group 2;
the comparison of the tables 1, 2 and examples 1-2 shows that the experimental results of example 1 are better than those of example 2 under different fermentation conditions by the method of the present invention, and both can remove the available copper content in the contaminated soil to different degrees, and preferably, the fermentation conditions of the microbial inoculum are selected from those described in example 1.
The control groups 1, 2 and examples 1, 3, 4, 5 in the table illustrate the healing effect of the method of the invention at different microbial agent application rates; preferably, the application amount of the microbial agent in the invention is 35 kg/mu.
In the table, comparison groups 1 and 2 and examples 1, 6 and 7 illustrate the repairing effect of the method of the invention under different planting densities of the Equisetum ramosissimum; preferably, the planting density of the Equisetum ramosissimum in the invention is 10 plants/m2。
In the table, comparison groups 1 and 2 and examples 1, 8 and 9 show that the application effects of the microbial mixed spore powder fungicide, the single penicillium oxalicum spore powder fungicide and the single bluish yellow fungus spore powder fungicide in combined remediation with the saxifraga stolonifera respectively are achieved, the examples 8 and 9 can reduce the content of effective copper in the polluted soil, but compared with the example 1, the effects are more different, and the mixed spore powder of the two strains can synergistically activate copper in the soil, so that the saxifraga stolonifera plants are enriched with more heavy metal copper.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.