Microbial purification and remediation method for petroleum hydrocarbon contaminated soil

Abstract

The invention is applicable to the technical field of soil remediation methods, and provides a microbial purification remediation method for petroleum hydrocarbon contaminated soil, which comprises the following steps: drying and crushing the petroleum hydrocarbon contaminated soil; fully mixing the crushed polluted soil with a soil remediation agent; the soil remediation agent is prepared from the following raw materials: modified cellulose aerogel, modified tourmaline, modified vermiculite, a microbial complex microbial inoculant, carbon powder, iron ore powder and humic acid, the microbial complex microbial inoculant is added, petroleum hydrocarbon is degraded by utilizing microorganisms, and the soil remediation agent has a good soil remediation effect and environmental friendliness and is suitable for being used for soil remediation. By adding the modified cellulose aerogel, a three-dimensional network repairing and purifying system is formed, and the purifying and repairing efficiency is improved; by adding the modified tourmaline, the PH value of the soil can be adjusted, microbial reproduction can be promoted, and the microbial activity can be improved; and by adding the modified vermiculite, the remediation and purification effects are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of soil remediation methods, and in particular relates to a microbial purification and remediation method for petroleum hydrocarbon-contaminated soil. Background Art

[0002] As an important energy source, oil is the blood of the modern economy. The consumption of oil is increasing year by year. At the same time, various leakage accidents during oil processing, transportation, storage and utilization have also caused petroleum hydrocarbon pollution in the soil. The recovery period of petroleum hydrocarbon contaminated soil is long and the impact range is wide, which has a significant impact on human living environment and human safety.

[0003] Soil pollution caused by petroleum hydrocarbons has attracted more and more attention. In addition to physical and chemical methods, microbial treatment methods have been developed in recent years. They have the advantages of good treatment effect, low cost, small impact on the environment, and no secondary pollution. However, the existing microbial treatment methods have a long repair cycle and poor stability. Summary of the invention

[0004] The present invention provides a microbial purification and restoration method for petroleum hydrocarbon contaminated soil, aiming to solve the above-mentioned problems.

[0005] The present invention is achieved by a microbial purification and remediation method for petroleum hydrocarbon contaminated soil, comprising the following steps: The petroleum hydrocarbon contaminated soil is dried and crushed to obtain contaminated soil with a particle size of 3-8 cm; Thoroughly mix the crushed contaminated soil with 2-4% of its mass of soil remediation agent; Regularly water, till and supplement nutrients to keep the soil moisture content at 25-35% at room temperature; Until the petroleum hydrocarbon content in the contaminated soil is lower than the permitted value, the restoration of the petroleum hydrocarbon contaminated soil is completed; The soil remediation agent comprises the following raw materials in parts by weight: 10-15 parts of modified cellulose aerogel, 5-20 parts of modified tourmaline, 5-15 parts of modified vermiculite, 80-100 parts of microbial composite agent, 3-7 parts of carbon powder, 4-9 parts of iron ore powder and 2-8 parts of humic acid.

[0006] Preferably, the soil remediation agent comprises the following raw materials in parts by weight: 11-14 parts of modified cellulose aerogel, 10-15 parts of modified tourmaline, 8-12 parts of modified vermiculite, 85-95 parts of microbial composite agent, 4-6 parts of carbon powder, 5-8 parts of iron ore powder, and 4-6 parts of humic acid.

[0007] Preferably, the soil remediation agent comprises the following raw materials in parts by weight: 12.5 parts of modified cellulose aerogel, 12.5 parts of modified tourmaline, 10 parts of modified vermiculite, 90 parts of microbial composite agent, 4 parts of carbon powder, 6.5 parts of iron ore powder, and 5 parts of humic acid.

[0008] Preferably, the preparation method of the modified cellulose aerogel is as follows: by weight, 6-12 parts of NaOH and 20-30 parts of urea are added to 80-100 parts of deionized water, stirred and mixed, and placed at -15 to -10°C for 10-15 minutes, then 10-15 parts of cellulose are added, stirred until the cellulose is completely dissolved, and then 2-5 parts of aspartic acid are added. After stirring evenly, the mixture is poured into a mold, allowed to stand, washed, and freeze-dried to obtain a modified cellulose aerogel. The modified cellulose aerogel has a three-dimensional network structure, low density, high specific surface area, and large porosity, provides more binding sites, and can adsorb a large amount of petroleum hydrocarbons and microbial composite agents. The two carboxyl groups of aspartic acid undergo esterification reaction with the hydroxyl groups of cellulose, chemically cross-linking the cellulose, and combining with other components to form a three-dimensional network repair and purification system to improve the purification and repair efficiency.

[0009] Preferably, the preparation method of the modified tourmaline is as follows: by weight, 8-15 parts of tourmaline, 1-3 parts of sodium chloride, and 4-8 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 125-145°C for 2-3h, filtered and washed with deionized water for 3 times, the filtered product was vacuum dried at 70-80°C and -0.06MPa for 5-10min, then mixed with 1-2 parts of sodium stearate, ground and sieved through 200-300 mesh to obtain modified tourmaline.

[0010] Tourmaline can automatically and permanently release negative ions. Negative ions have strong oxidizing properties and can adjust the pH value of the liquid in the soil to neutral to adjust the pH value of the soil. Tourmaline can continuously generate DC static electricity, release minerals and trace elements, promote the growth and reproduction of microorganisms, and improve the activity of microorganisms. First, sodium chloride and hydrochloric acid are used to increase the specific surface area and porosity of tourmaline and improve its adsorption performance. Then, sodium stearate is ground together with the tourmaline to allow the sodium stearate to fully enter the gaps in the tourmaline, thereby improving the dispersibility of the tourmaline. This allows the tourmaline to fully combine with the microbial composite agent and other components and be fully and evenly mixed with the soil, thereby improving the repair and purification effect.

[0011] Preferably, the preparation method of the modified vermiculite is as follows: 10-20 parts by weight of vermiculite are washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a concentration of 2-3 mol / L and stirred at 75-85° C. for 60-80 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves, and then 60-70 parts of a sodium carbonate solution with a concentration of 0.1-0.3 mmol / L octadecyltrimethylammonium chloride solution, heated to 70-90℃ for reaction for 1-2h, filtered and washed 3 times with distilled water, and dried at 90-100℃ to obtain modified vermiculite; firstly, the vermiculite is sodiumized with sodium carbonate to increase the cation exchange capacity of the vermiculite, and then microwaved to further activate the vermiculite, and finally octadecyltrimethylammonium chloride is added to cover the surface of the vermiculite with organic groups or insert them into the interlayers for cation exchange reaction, so as to obtain vermiculite with large interlayer spacing, better adsorption and improved repair and purification effect.

[0012] Preferably, the microwave power of the microwave treatment is 600-800 W, and the time is 3-5 min.

[0013] Preferably, the microbial composite bacterial agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorans, and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial solution is 120-125 cfu / ml.

[0014] Preferably, the crushed contaminated soil is pretreated and then fully mixed with the soil remediation agent, and the pretreatment method is as follows: half of the crushed contaminated soil is spread on the culture medium, and then the bacterial cellulose fermentation liquid is sprayed on the surface, and then the other half of the contaminated soil is spread and covered, and cultured at 28-36°C in a culture environment for 3-5 days to obtain pretreated contaminated soil; by spraying the bacterial cellulose fermentation liquid, during the culture process, the bacterial cellulose grows into the soil, interweaves with each other to form a developed ultra-fine network structure, improves the air permeability of the soil, fully transports the soil remediation agent into the soil, and is conducive to the growth and reproduction of microorganisms, thereby improving the purification and remediation efficiency.

[0015] Preferably, the bacterial cellulose fermentation liquid is Gluconacetobacter cellulose fermentation liquid, and the mass ratio of the bacterial cellulose fermentation liquid to the contaminated soil is 1:50-80.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects: The microbial purification and remediation method for petroleum hydrocarbon contaminated soil provided by the present invention has good soil remediation effect and environmental friendliness by adding microbial composite bacterial agents and utilizing microorganisms to degrade petroleum hydrocarbons. The modified cellulose aerogel is added to have a three-dimensional network structure and can adsorb a large amount of petroleum hydrocarbons and microbial composite bacterial agents to form a three-dimensional network remediation and purification system, thereby improving the purification and remediation efficiency. The modified tourmaline is added to adjust the soil pH value, promote microbial reproduction, and improve microbial activity. The modified vermiculite is added to further improve the remediation and purification effect. The carbon powder and iron ore powder are added to increase the soil fertility, improve the soil air permeability and water retention, and the iron ore powder and the carbon powder form a primary battery reaction in the soil to degrade and remediate the petroleum hydrocarbon contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of a microbial purification and remediation method for petroleum hydrocarbon contaminated soil provided in Examples 1-5 of the present invention.

[0018] Figure 2 This is a flow chart of a microbial purification and remediation method for petroleum hydrocarbon contaminated soil provided in Example 6 of the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0020] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0021] Example 1 The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 1 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 3 cm; The crushed contaminated soil is fully mixed with a soil remediation agent that accounts for 2% of its mass; Regularly water, till and supplement nutrients to keep the soil moisture content at 25% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0022] The soil remediation agent comprises the following raw materials in parts by weight: 10 parts of modified cellulose aerogel, 5 parts of modified tourmaline, 5 parts of modified vermiculite, 80 parts of microbial composite agent, 3 parts of carbon powder, 4 parts of iron ore powder, and 2 parts of humic acid.

[0023] The microbial composite bacterial agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorans, and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial solution is 120 cfu / ml.

[0024] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: by weight, 6 parts of NaOH and 20 parts of urea are added to 80 parts of deionized water, stirred and mixed, and then placed at -15°C for 10 minutes, and then 10 parts of cellulose are added, stirred until the cellulose is completely dissolved, and then 2 parts of aspartic acid are added. After stirring evenly, the mixture is poured into a mold, left to stand, washed, and freeze-dried to obtain a modified cellulose aerogel.

[0025] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 8 parts of tourmaline, 1 part of sodium chloride, and 4 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 125°C for 2 hours, filtered and washed with deionized water 3 times, the filtered product was vacuum dried at 70°C and -0.06MPa for 5 minutes, and then mixed with 1 part of sodium stearate, ground and sieved through a 200-mesh sieve to obtain modified tourmaline.

[0026] Furthermore, the preparation method of the modified vermiculite is as follows: 10 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a concentration of 2 mol / L and stirred at 75° C. for 60 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves at a microwave power of 600 W for 3 min, and then 60 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.1 mmol / L is added, the temperature is raised to 70° C. for reaction for 1 h, filtered, washed with distilled water for 3 times, and dried at 90° C. to obtain the modified vermiculite.

[0027] Example 2 The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 1 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 3 cm; The crushed contaminated soil is fully mixed with a soil remediation agent that accounts for 2% of its mass; Regularly water, till and supplement nutrients to keep the soil moisture content at 25% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0028] The soil remediation agent includes the following raw materials in parts by weight: 11 parts of modified cellulose aerogel, 10 parts of modified tourmaline, 8 parts of modified vermiculite, 85 parts of microbial composite agent, 4 parts of carbon powder, 5 parts of iron ore powder, and 4 parts of humic acid.

[0029] The microbial composite bacterial agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorans, and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial solution is 120 cfu / ml.

[0030] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: by weight, 6 parts of NaOH and 20 parts of urea are added to 80 parts of deionized water, stirred and mixed, and then placed at -15°C for 10 minutes, and then 10 parts of cellulose are added, stirred until the cellulose is completely dissolved, and then 2 parts of aspartic acid are added. After stirring evenly, the mixture is poured into a mold, left to stand, washed, and freeze-dried to obtain a modified cellulose aerogel.

[0031] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 8 parts of tourmaline, 1 part of sodium chloride, and 4 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 125°C for 2 hours, filtered and washed with deionized water 3 times, the filtered product was vacuum dried at 70°C and -0.06MPa for 5 minutes, and then mixed with 1 part of sodium stearate, ground and sieved through a 200-mesh sieve to obtain modified tourmaline.

[0032] Furthermore, the preparation method of the modified vermiculite is as follows: 10 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a concentration of 2 mol / L and stirred at 75° C. for 60 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves at a microwave power of 600 W for 3 min, and then 60 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.1 mmol / L is added, the temperature is raised to 70° C. for reaction for 1 h, filtered, washed with distilled water for 3 times, and dried at 90° C. to obtain the modified vermiculite.

[0033] Example 3 The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 1 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 5 cm; The crushed contaminated soil is fully mixed with a soil remediation agent that accounts for 3% of its mass; Regularly water, till and supplement nutrients to keep the soil moisture content at 30% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0034] The soil remediation agent includes the following raw materials in parts by weight: 12.5 parts of modified cellulose aerogel, 12.5 parts of modified tourmaline, 10 parts of modified vermiculite, 90 parts of microbial composite agent, 4 parts of carbon powder, 6.5 parts of iron ore powder, and 5 parts of humic acid.

[0035] The microbial composite agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorax, and Rhodococcus erythrocytes, and the concentration of the mixed bacterial solution is 122 cfu / ml.

[0036] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: 9 parts of NaOH and 25 parts of urea are added to 90 parts of deionized water by weight, the mixture is stirred and placed at -12°C for 13 minutes, 12.5 parts of cellulose are added, the mixture is stirred until the cellulose is completely dissolved, 3.5 parts of aspartic acid are added, the mixture is stirred evenly, poured into a mold, left to stand, washed and freeze-dried to obtain a modified cellulose aerogel.

[0037] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 11.5 parts of tourmaline, 2 parts of sodium chloride, and 6 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 135°C for 2.5 hours, filtered and washed with deionized water three times, the filtered product was vacuum dried at 75°C and -0.06MPa for 8 minutes, and then mixed with 1.5 parts of sodium stearate, ground and sieved through a 250-mesh sieve to obtain modified tourmaline.

[0038] Furthermore, the preparation method of the modified vermiculite is as follows: 15 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a concentration of 2.5 mol / L and stirred at 80° C. for 70 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves at a microwave power of 700 W for 4 min, and then 65 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.2 mmol / L is added, the temperature is raised to 80° C. for reaction for 1.5 h, filtered, washed with distilled water for 3 times, and dried at 95° C. to obtain the modified vermiculite.

[0039] Example 4 The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 1 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 8 cm; The crushed contaminated soil is fully mixed with a soil remediation agent that accounts for 4% of its mass; Regularly water, till and supplement nutrients to keep the soil moisture content at 35% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0040] The soil remediation agent includes the following raw materials in parts by weight: 14 parts of modified cellulose aerogel, 15 parts of modified tourmaline, 12 parts of modified vermiculite, 95 parts of microbial composite agent, 6 parts of carbon powder, 8 parts of iron ore powder, and 6 parts of humic acid.

[0041] The microbial composite agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorans, and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial solution is 125 cfu / ml.

[0042] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: by weight, 12 parts of NaOH and 30 parts of urea are added to 100 parts of deionized water, the mixture is stirred and placed at -10°C for 15 minutes, and then 15 parts of cellulose are added and stirred until the cellulose is completely dissolved, and then 5 parts of aspartic acid are added, stirred evenly and poured into a mold, left to stand, washed and freeze-dried to obtain a modified cellulose aerogel.

[0043] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 15 parts of tourmaline, 3 parts of sodium chloride, and 8 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 145°C for 3 hours, filtered and washed with deionized water 3 times, the filtered product was vacuum dried at 80°C and -0.06MPa for 10 minutes, then ground with 2 parts of sodium stearate and passed through a 300-mesh sieve to obtain modified tourmaline.

[0044] Furthermore, the preparation method of the modified vermiculite is as follows: 20 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a weight of 12 times and a concentration of 3 mol / L, stirred at 85° C. for 80 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves with a microwave power of 800 W for 5 min, and then 70 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.3 mmol / L is added, the temperature is raised to 90° C. for reaction for 2 h, filtered, washed with distilled water for 3 times, and dried at 100° C. to obtain the modified vermiculite.

[0045] Example 5 The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 1 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 8 cm; The crushed contaminated soil is fully mixed with a soil remediation agent that accounts for 4% of its mass; Regularly water, till and supplement nutrients to keep the soil moisture content at 35% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0046] The soil remediation agent includes the following raw materials in parts by weight: 15 parts of modified cellulose aerogel, 20 parts of modified tourmaline, 15 parts of modified vermiculite, 100 parts of microbial composite agent, 7 parts of carbon powder, 9 parts of iron ore powder, and 8 parts of humic acid.

[0047] The microbial composite agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorans, and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial solution is 125 cfu / ml.

[0048] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: by weight, 12 parts of NaOH and 30 parts of urea are added to 100 parts of deionized water, the mixture is stirred and placed at -10°C for 15 minutes, and then 15 parts of cellulose are added and stirred until the cellulose is completely dissolved, and then 5 parts of aspartic acid are added, stirred evenly and poured into a mold, left to stand, washed and freeze-dried to obtain a modified cellulose aerogel.

[0049] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 15 parts of tourmaline, 3 parts of sodium chloride, and 8 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 145°C for 3 hours, filtered and washed with deionized water 3 times, the filtered product was vacuum dried at 80°C and -0.06MPa for 10 minutes, then ground with 2 parts of sodium stearate and passed through a 300-mesh sieve to obtain modified tourmaline.

[0050] Furthermore, the preparation method of the modified vermiculite is as follows: 20 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a weight of 12 times and a concentration of 3 mol / L, stirred at 85° C. for 80 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves with a microwave power of 800 W for 5 min, and then 70 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.3 mmol / L is added, the temperature is raised to 90° C. for reaction for 2 h, filtered, washed with distilled water for 3 times, and dried at 100° C. to obtain the modified vermiculite.

[0051] Example 6 (Based on Example 3, the crushed contaminated soil is pre-treated) The present invention provides a method for microbial purification and remediation of petroleum hydrocarbon contaminated soil. Figure 2 As shown, the following steps are included: The petroleum hydrocarbon contaminated soil was dried and crushed to obtain contaminated soil with a particle size of 5 cm; Spread half of the crushed contaminated soil on the culture medium, then spray the bacterial cellulose fermentation liquid on the surface, and then spread the other half of the contaminated soil on the culture medium, and culture it at 28-36°C in a culture environment for 3-5 days to obtain pretreated contaminated soil; Thoroughly mix the pretreated contaminated soil with 3% of its mass of soil remediation agent; Regularly water, till and supplement nutrients to keep the soil moisture content at 30% at room temperature; The remediation of petroleum hydrocarbon contaminated soil is completed until the petroleum hydrocarbon content in the contaminated soil is lower than the allowable value.

[0052] The soil remediation agent includes the following raw materials in parts by weight: 12.5 parts of modified cellulose aerogel, 12.5 parts of modified tourmaline, 10 parts of modified vermiculite, 90 parts of microbial composite agent, 4 parts of carbon powder, 6.5 parts of iron ore powder, and 5 parts of humic acid.

[0053] The microbial composite agent includes Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanovorax, and Rhodococcus erythrocytes, and the concentration of the mixed bacterial solution is 122 cfu / ml.

[0054] In this embodiment, the preparation method of the modified cellulose aerogel is as follows: 9 parts of NaOH and 25 parts of urea are added to 90 parts of deionized water by weight, the mixture is stirred and placed at -12°C for 13 minutes, 12.5 parts of cellulose are added, the mixture is stirred until the cellulose is completely dissolved, 3.5 parts of aspartic acid are added, the mixture is stirred evenly, poured into a mold, left to stand, washed and freeze-dried to obtain a modified cellulose aerogel.

[0055] Furthermore, the preparation method of the modified tourmaline is as follows: by weight, 11.5 parts of tourmaline, 2 parts of sodium chloride, and 6 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 135°C for 2.5 hours, filtered and washed with deionized water three times, the filtered product was vacuum dried at 75°C and -0.06MPa for 8 minutes, and then mixed with 1.5 parts of sodium stearate, ground and sieved through a 250-mesh sieve to obtain modified tourmaline.

[0056] Furthermore, the preparation method of the modified vermiculite is as follows: 15 parts of vermiculite are taken by weight, washed, dried, and then crushed through a 400-mesh sieve to obtain vermiculite powder; the vermiculite powder is added to a sodium carbonate solution with a concentration of 2.5 mol / L and stirred at 80° C. for 70 min, ultrasonically dispersed while stirring, filtered, and washed with deionized water for 3 times to obtain an intermediate product; the intermediate product is treated with microwaves at a microwave power of 700 W for 4 min, and then 65 parts of octadecyltrimethylammonium chloride solution with a concentration of 0.2 mmol / L is added, the temperature is raised to 80° C. for reaction for 1.5 h, filtered, washed with distilled water for 3 times, and dried at 95° C. to obtain the modified vermiculite.

[0057] In this embodiment, the bacterial cellulose fermentation liquid is a Gluconacetobacter cellulose fermentation liquid, and the mass ratio of the bacterial cellulose fermentation liquid to the contaminated soil is 1:50-80. Comparative Example 1: Compared with Example 3, the modified cellulose aerogel in the soil remediation agent is replaced by ordinary cellulose aerogel.

[0058] Comparative Example 2: Compared with Example 3, the modified tourmaline in the soil remediation agent is replaced with ordinary tourmaline.

[0059] Comparative Example 3: Compared with Example 3, the modified vermiculite in the soil remediation agent is replaced with ordinary vermiculite.

[0060] Comparative Example 4: Compared with Example 3, the modified cellulose aerogel in the soil remediation agent is replaced by ordinary cellulose aerogel, the modified tourmaline is replaced by ordinary tourmaline, and the modified vermiculite is replaced by ordinary vermiculite.

[0061] Comparative Example 5: A commercially available soil remediation agent containing microbial agents was used.

[0062] experiment Contaminated soil near gas stations in three different regions and with different pollution degrees was collected as samples, which were divided into sample A, sample B and sample C. As three parallel experiments, the above samples A, B and C were treated according to the remediation methods of Examples 1-6 and Comparative Examples 1-5, respectively, and the amount of oil reduction in the contaminated soil on the 30th day of remediation was measured. The test results are shown in Table 1 below: Group A sample oil reduction / % B sample oil reduction / % C sample oil reduction / % Example 1 86.1 85.2 86.2 Example 2 86.3 85.6 86.3 Example 3 86.7 85.9 86.5 Example 4 86.5 85.8 86.4 Example 5 86.2 85.4 86.2 Example 6 93.8 92.5 93.5 Comparative Example 1 65.8 65.1 65.5 Comparative Example 2 66.4 65.5 66.1 Comparative Example 3 64.6 63.2 64.3 Comparative Example 4 38.2 36.9 37.8 Comparative Example 5 36.9 33.5 34.4 It can be seen from the above results that the repair and purification method of the present invention has a good repair effect, especially by adding modified cellulose aerogel, modified tourmaline and modified vermiculite to the soil remediation agent. The three have a synergistic effect and can be combined with the microbial composite agent to improve the repair efficiency.

[0063] It should be noted that, for the above embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A microbial purification and remediation method for petroleum hydrocarbon contaminated soil, characterized in that: include: The petroleum hydrocarbon contaminated soil is dried and crushed to obtain contaminated soil with a particle size of 3-8 cm; Thoroughly mix the crushed contaminated soil with 2-4% of its mass of soil remediation agent; Regularly water, till and supplement nutrients to keep the soil moisture content at 25-35% at room temperature; Until the petroleum hydrocarbon content in the contaminated soil is lower than the permitted value, the restoration of the petroleum hydrocarbon contaminated soil is completed; The soil remediation agent comprises the following raw materials in parts by weight: 10-15 parts of modified cellulose aerogel, 5-20 parts of modified tourmaline, 5-15 parts of modified vermiculite, 80-100 parts of microbial composite agent, 3-7 parts of carbon powder, 4-9 parts of iron ore powder and 2-8 parts of humic acid.

2. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The soil remediation agent comprises the following raw materials in parts by weight: 11-14 parts of modified cellulose aerogel, 10-15 parts of modified tourmaline, 8-12 parts of modified vermiculite, 85-95 parts of microbial composite agent, 4-6 parts of carbon powder, 5-8 parts of iron ore powder and 4-6 parts of humic acid.

3. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 2, characterized in that: The soil remediation agent includes the following raw materials in parts by weight: 12.5 parts of modified cellulose aerogel, 12.5 parts of modified tourmaline, 10 parts of modified vermiculite, 90 parts of microbial composite agent, 4 parts of carbon powder, 6.5 parts of iron ore powder, and 5 parts of humic acid.

4. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The preparation method of the modified cellulose aerogel is as follows: by weight, 6-12 parts of NaOH and 20-30 parts of urea are added to 80-100 parts of deionized water, the mixture is stirred and placed at -15 to -10°C for 10-15 minutes, 10-15 parts of cellulose are added, the mixture is stirred until the cellulose is completely dissolved, 2-5 parts of aspartic acid are added, the mixture is stirred evenly, the mixture is poured into a mold, the mixture is allowed to stand, washed and freeze-dried to obtain the modified cellulose aerogel.

5. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The preparation method of the modified tourmaline is as follows: by weight, 8-15 parts of tourmaline, 1-3 parts of sodium chloride and 4-8 parts of hydrochloric acid are added to a hydrothermal reactor, reacted at 125-145° C. for 2-3 hours, filtered and washed with deionized water for 3 times, the filtered product is vacuum dried at 70-80° C. and -0.06 MPa for 5-10 minutes, then mixed with 1-2 parts of sodium stearate, ground and sieved through a 200-300 mesh sieve to obtain the modified tourmaline.

6. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The preparation method of the modified vermiculite is as follows: taking 10-20 parts of vermiculite by weight, washing, drying, and then crushing through a 400-mesh sieve to obtain vermiculite powder; adding the vermiculite powder to a sodium carbonate solution with a weight of 8-12 times and a concentration of 2-3 mol / L, stirring at 75-85° C. for 60-80 minutes, using ultrasonic dispersion while stirring, filtering and washing with deionized water for 3 times to obtain an intermediate product; treating the intermediate product with microwaves, then adding 60-70 parts of an octadecyltrimethylammonium chloride solution with a concentration of 0.1-0.3 mmol / L, heating to 70-90° C. for reaction for 1-2 hours, filtering, washing with distilled water for 3 times, and drying at 90-100° C. to obtain the modified vermiculite.

7. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 6, characterized in that: The microwave power of the microwave treatment is 600-800W, and the time is 3-5min.

8. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The microbial composite bacterial agent comprises Pseudomonas aeruginosa, Bacillus, Flavobacterium, Gordonia alkanevorans and Rhodococcus erythrorhizium, and the concentration of the mixed bacterial liquid is 120-125 cfu / ml.

9. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 6, characterized in that: The crushed contaminated soil is pretreated and then fully mixed with the soil remediation agent. The pretreatment method is as follows: half of the crushed contaminated soil is spread on the culture medium, and then bacterial cellulose fermentation liquid is sprayed on the surface, and then the other half of the contaminated soil is spread and covered, and statically cultured at 28-36° C. in a culture environment for 3-5 days to obtain pretreated contaminated soil.

10. The microbial purification and remediation method for petroleum hydrocarbon contaminated soil according to claim 9, characterized in that: The bacterial cellulose fermentation liquid is a Gluconacetobacter cellulose fermentation liquid, and the mass ratio of the bacterial cellulose fermentation liquid to the contaminated soil is 1:50-80.

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