A method for remediation of chromium-contaminated soil using immobilized Acinetobacter venereum combined with electro-osmosis

Abstract

The application provides a method for repairing chromium-polluted soil by immobilized Acinetobacter venetianus combined with electro-osmosis. 600 S1: preparing double-pore-size structure glassy carbon particles; S2: preparing an Acinetobacter venetianus suspension with OD=0.8; S3: immobilizing the Acinetobacter venetianus; S4: soil repair test; and S5: sampling and determining the chromium ion removal effect. The double-pore-size structure glassy carbon particles have the advantages of high mechanical strength and stable chemical properties, and are convenient for repeated use. The pores distributed on the double-pore-size structure glassy carbon particles have a pore size of 4+ / -1 nm and 40+ / -3 nm. The double-pore-size structure can greatly reduce the mass transfer resistance, and has a large specific surface area and high porosity. After electro-osmosis, chromium ions are gathered at the cathode, and the structure can easily flow through the chromium ions and increase the adsorption of the chromium ions.

Description

Technical Field

[0001] This invention relates to the technical field of soil treatment, and specifically to a method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis. Background Technology

[0002] With the rapid development of industry and mining, soil heavy metal pollution has become increasingly serious, posing a global environmental problem. Chromium and its compounds are common raw materials used in metallurgy, electroplating, leather making, and pigment industries. These industries generate large amounts of chromium-containing wastewater and waste residue, which, if improperly disposed of, lead to soil pollution. When these lands are converted to residential or public use due to urbanization, severely contaminated sites typically require soil remediation. Currently, physical, chemical, and biological remediation methods are mainly used domestically and internationally to remediate heavy metal-contaminated soil through the following pathways: ① dilution, i.e., reducing the concentration of heavy metals in the soil; ② altering the form of heavy metals, fixing or passivating them to reduce their mobility and bioavailability in the environment; ③ removing heavy metals from the soil. Because single remediation technologies have significant limitations and are generally inefficient, while phytoremediation is time-consuming, researching combined remediation technologies for contaminated soil to improve the remediation effect of heavy metal-contaminated soil is a growing trend. Summary of the Invention

[0003] Technical Problem to be Solved: To address the aforementioned technical problems, the purpose of this invention is to provide a method for remediating chromium-contaminated soil using immobilized Acinetobacter ventricula combined with electro-osmosis. This method employs dual-pore structured vitreous carbon particles. Compared to ordinary carbon particles, vitreous carbon has outstanding characteristics such as high mechanical strength and good chemical stability, facilitating reuse. The pores distributed on the dual-pore structure of the vitreous carbon particles have diameters of 4±1 nm and 40±3 nm. This dual-pore structure can significantly reduce mass transfer resistance, and also has a large specific surface area and high porosity. During electro-osmosis, chromium ions accumulate in large quantities at the cathode. This structure facilitates the flow of chromium ions, increasing their adsorption.

[0004] Technical Solution: A method for remediating chromium-contaminated soil using immobilized Acinetobacter venereum combined with electro-osmosis, comprising the following steps (by weight):

[0005] S1: Prepare glassy carbon particles with a dual-pore structure, wherein the dual-pore structure is: the pores distributed on the glassy carbon particles have pore sizes of 4±1nm and 40±3nm;

[0006] S2: Preparation of OD 600 =0.8 Acinetobacter velifolia suspension;

[0007] S3: Immobilization of Acinetobacter venereum: Take 1 part of dual-pore structured vitreous carbon particles and add them to 100 parts of LB medium. Sterilize at 121℃ for 20 min, cool to room temperature, add Acinetobacter venereum suspension at a volume ratio of 2%, and incubate at 30℃ and 160 r / min for 24 h. Wash with physiological saline 2 to 3 times to obtain dual-pore structured vitreous carbon particles-Acinetobacter venereum immobilization carrier.

[0008] S4: Soil remediation experiment: A cathode and anode were set up, and the cathode and anode were respectively equipped with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte and allowed to stand for equilibration for 24 hours; a dual-pore structured vitreous carbon particle-Acinetobacter venereum immobilization carrier was placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm; S5: Sampling was carried out to determine the chromium ion removal effect.

[0009] Furthermore, the particle size of the dual-pore structured glassy carbon particles is 100-150 μm.

[0010] Furthermore, the preparation method of the dual-pore structured glassy carbon particles is as follows:

[0011] S11: Phenol, formaldehyde solution with a mass fraction of 37-40%, nano calcium carbonate, polyethylene glycol 1500 and ammonia are mixed, stirred and heated to the reaction temperature of 80°C. After reacting for 15 hours, hexamethylenetetramine is added, the temperature is raised to 95°C and the stirring rate is kept constant. The reaction ends after 4 hours.

[0012] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0013] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 200-250℃;

[0014] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0015] S15: Activated with CO2 at 500-700℃ to obtain glassy carbon with a pore size of 4±1nm;

[0016] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure.

[0017] Furthermore, the particle size of the nano-calcium carbonate in S11 is 40±1nm.

[0018] Furthermore, in S11, the mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:(1-3):2:2.5:8; the molar ratio of phenol to formaldehyde in a formaldehyde solution with a mass fraction of 37-40% is 1:1.3.

[0019] Furthermore, the stirring speed in S11 is 300-350 rpm.

[0020] Furthermore, the mass ratio of phenolic resin particles to hexamethylenetetramine in S13 is 10:(0.5-2).

[0021] Furthermore, the electrolyte in S4, consisting of 0.1M citric acid monohydrate and 0.01M disodium ethylenediaminetetraacetate, needs to be replaced every 24 hours.

[0022] Beneficial effects:

[0023] 1. Compared with ordinary carbon particles, the vitrified carbon used in this invention has outstanding characteristics of high mechanical strength and good chemical stability, making it easy to reuse. However, conventional vitrified carbon has ultra-micro closed pores, and activation can only form a porous structure on the surface, which cannot achieve overall activation. However, by using the method of this invention, a dual-pore structure can be obtained. The pores distributed on the vitrified carbon particles have a pore size of 4±1nm and 40±3nm. The dual-pore structure can greatly reduce mass transfer resistance, and has a large specific surface area and high porosity. When electro-osmosis occurs, chromium ions accumulate in large quantities at the cathode. This structure can facilitate the flow of chromium ions and increase the adsorption of chromium ions.

[0024] 2. In this invention, Acinetobacter veneris is fixed with glassy carbon, which facilitates repeated use and ensures uniform dispersion. Currently, Acinetobacter veneris is used for the degradation of diesel fuel. This invention creatively applies it to the further adsorption of chromium ions. Experiments show that the effect is very good, and its mechanism of action needs further research.

[0025] 3. This invention employs an electro-osmosis method, which uses an electric field to cause chromium ions to migrate towards the vicinity of the cathode. This invention uses a graded voltage gradient treatment method. In the initial stage of treatment, it is mainly used for the migration of chromium ions, and in the later stage of treatment, it is mainly used for the stabilization of chromium ions. This method is not only effective, but also saves energy and is suitable for large-scale use. Detailed Implementation

[0026] This invention proposes a method for remediating chromium-contaminated soil using immobilized Acinetobacter venereum combined with electro-osmosis. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following will provide a more detailed description of the invention with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0027] Example 1

[0028] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0029] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 300rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:1:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0030] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0031] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 200℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:1.5.

[0032] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0033] S15: Activated with CO2 at 500℃ to obtain glassy carbon with a pore size of 4±1nm;

[0034] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0035] The porosity was measured to be 76.5%.

[0036] Example 2

[0037] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0038] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 310rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:2:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0039] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0040] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 210℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:1.5.

[0041] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0042] S15: Activated with CO2 at 550℃ to obtain glassy carbon with a pore size of 4±1nm;

[0043] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0044] The porosity was measured to be 79.4%.

[0045] Example 3

[0046] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0047] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 320rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:3:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0048] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0049] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 220℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:1.5.

[0050] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0051] S15: Activated with CO2 at 600℃ to obtain glassy carbon with a pore size of 4±1nm;

[0052] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0053] The porosity was measured to be 81.7%.

[0054] Example 4

[0055] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0056] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 330rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:2:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0057] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0058] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 230℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:0.5.

[0059] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0060] S15: Activated with CO2 at 600℃ to obtain glassy carbon with a pore size of 4±1nm;

[0061] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0062] The porosity was measured to be 76.2%.

[0063] Example 5

[0064] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0065] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 340rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:2:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0066] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0067] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 240℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:1.

[0068] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0069] S15: Activated with CO2 at 650℃ to obtain glassy carbon with a pore size of 4±1nm;

[0070] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0071] The porosity was measured to be 78.1%.

[0072] Example 6

[0073] The preparation method of dual-pore structured glassy carbon particles is as follows:

[0074] S11: Phenol, a 40% formaldehyde solution, nano-calcium carbonate with a particle size of 40±1nm, polyethylene glycol 1500, and ammonia are mixed and heated to a reaction temperature of 80℃ at a stirring speed of 350rpm. After reacting for 15h, hexamethylenetetramine is added, the temperature is raised to 95℃, and the stirring speed is kept constant. The reaction ends after 4h. The mass ratio of phenol, nano-calcium carbonate, polyethylene glycol 1500, ammonia, and hexamethylenetetramine is 100:2:2:2.5:8. The molar ratio of phenol to formaldehyde in the 40% formaldehyde solution is 1:1.3.

[0075] S12: Wash with water until the upper filtrate is clear, then filter by suction and dry in an oven at 80°C to obtain phenolic resin particles;

[0076] S13: Add hexamethylenetetramine to phenolic resin particles, ball mill and solidify for 1 hour, and cure at 250℃; the mass ratio of phenolic resin particles to hexamethylenetetramine is 10:2.

[0077] S14: Carbonization is carried out in four stages: First stage: heating to 300℃ at a heating rate of 3℃ / min; Second stage: heating to 800℃ at a heating rate of 1℃ / min; Third stage: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; Fourth stage: natural cooling; The nitrogen flow rate during the entire carbonization process is 100 mL / min.

[0078] S15: Activated with CO2 at 700℃ to obtain glassy carbon with a pore size of 4±1nm;

[0079] S16: Wash the glassy carbon with a pore size of 4±1nm with dilute hydrochloric acid to obtain glassy carbon particles with a dual-pore structure of 4±1nm and 40±3nm.

[0080] The porosity was measured to be 80.0%.

[0081] Example 7

[0082] Preparation of OD 600 The steps for preparing a 0.8% Acinetobacter venereum suspension are as follows:

[0083] S21: Acinetobacter venereum was inoculated onto LB solid medium and cultured in an incubator at 30°C to obtain slant cells; the composition of LB solid medium was: 5 g / L yeast extract, 10 g / L NaCl, 10 g / L peptone, 15-20 g / L agar, and deionized water as the solvent;

[0084] S22: Inoculate the slant culture cells into LB liquid medium and incubate at 30℃ and 160rpm for 24h; LB liquid medium composition: 5g / L yeast extract, 10g / L NaCl, 10g / L peptone, solvent is deionized water;

[0085] S23: Transfer the inoculum to fresh LB liquid medium at a volume ratio of 1%, incubate for 12 hours, transfer the culture medium to a centrifuge tube, centrifuge at 6000 rpm for 5 minutes, discard the supernatant, rinse with sterile water and centrifuge again. Repeat this process 3 times, adjusting the OD value to [value missing]. 600 Acinetobacter veneris suspension with a concentration of 0.8.

[0086] The following experiments were conducted using the dual-pore structured glassy carbon particles prepared in Examples 2, 3, 5, and 6, respectively:

[0087] Example 8

[0088] Immobilization of Acinetobacter veneriense, by weight:

[0089] Take one part of the dual-pore structured vitreous carbon particles prepared in Example 2, add it to 100 parts of LB medium, sterilize at 121°C for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, incubate at 30°C and 160 r / min for 24 h, and wash three times with physiological saline to obtain the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier.

[0090] Example 9

[0091] Immobilization of Acinetobacter veneriense, by weight:

[0092] Take one part of the dual-pore structured vitreous carbon particles prepared in Example 3, add it to 100 parts of LB medium, sterilize at 121°C for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, incubate at 30°C and 160 r / min for 24 h, and wash three times with physiological saline to obtain the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier.

[0093] Example 10

[0094] Immobilization of Acinetobacter veneriense, by weight:

[0095] Take one part of the dual-pore structured vitreous carbon particles prepared in Example 5, add it to 100 parts of LB medium, sterilize at 121°C for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, incubate at 30°C and 160 r / min for 24 h, and wash three times with physiological saline to obtain the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier.

[0096] Example 11

[0097] Immobilization of Acinetobacter veneriense, by weight:

[0098] Take one part of the dual-pore structured vitreous carbon particles prepared in Example 6 and add it to 100 parts of LB medium. Sterilize at 121°C for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, and incubate at 30°C and 160 r / min for 24 h. After washing three times with physiological saline, the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier is obtained.

[0099]

[0100] The following experiments were conducted using the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carriers prepared in Examples 9 and 11, respectively. The chromium-contaminated soil was divided into high-concentration chromium-contaminated soil (chromium ion concentration of 100 mg / kg) and low-concentration chromium-contaminated soil (chromium ion concentration of 5 mg / kg). The amount of dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier was 0.5 g / kg of chromium-contaminated soil.

[0101] Example 12

[0102] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0103] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0104] S2: Take a sample and determine the chromium ion removal effect.

[0105] Example 13

[0106] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0107] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneritratus combined with electro-osmotic infiltration, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneritratus immobilization carrier prepared in Example 11 were placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0108] S2: Take a sample and determine the chromium ion removal effect.

[0109] Example 14

[0110] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0111] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0112] S2: Take a sample and determine the chromium ion removal effect.

[0113] Example 15

[0114] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0115] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneritratus combined with electro-osmotic infiltration, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneritratus immobilization carrier prepared in Example 11 were placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0116] S2: Take a sample and determine the chromium ion removal effect.

[0117] Comparative Example 1-1

[0118] The difference between this embodiment and Embodiment 12 is that conventional carbon particles are used, specifically:

[0119] S1: Preparation of carbon particles: The purchased phenolic resin particles were carbonized. The first stage was: heating to 300℃ at a heating rate of 3℃ / min; the second stage was: heating to 800℃ at a heating rate of 1℃ / min; the third stage was: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; the fourth stage was: natural cooling. The nitrogen flow rate was 100 mL / min throughout the carbonization process, resulting in conventional carbon particles.

[0120] S2: Immobilized Acinetobacter venereum, by weight:

[0121] Take one part of the prepared carbon particles and add them to 100 parts of LB medium. Sterilize at 121℃ for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, and incubate at 30℃ and 160 r / min for 24 h. Wash three times with physiological saline to obtain the carbon particle-Acinetobacter veneris immobilization vector.

[0122] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0123] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmotic remediation, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the prepared carbon particle-Acinetobacter veneris immobilization carrier was placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0124] S2: Take a sample and determine the chromium ion removal effect.

[0125] Comparative Examples 1-2

[0126] The difference between this embodiment and Embodiment 14 is that conventional carbon particles are used, specifically:

[0127] S1: Preparation of carbon particles: The purchased phenolic resin particles were carbonized. The first stage was: heating to 300℃ at a heating rate of 3℃ / min; the second stage was: heating to 800℃ at a heating rate of 1℃ / min; the third stage was: heating to 1000℃ at a heating rate of 5℃ / min and holding at that temperature for 30 min; the fourth stage was: natural cooling. The nitrogen flow rate was 100 mL / min throughout the carbonization process, resulting in conventional carbon particles.

[0128] S2: Immobilized Acinetobacter venereum, by weight:

[0129] Take one part of the prepared carbon particles and add them to 100 parts of LB medium. Sterilize at 121℃ for 20 min, cool to room temperature, add Acinetobacter veneris suspension at a volume ratio of 2%, and incubate at 30℃ and 160 r / min for 24 h. Wash three times with physiological saline to obtain the carbon particle-Acinetobacter veneris immobilization vector.

[0130] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0131] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmotic remediation, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the prepared carbon particle-Acinetobacter veneris immobilization carrier was placed at the cathode, and a graded voltage gradient was set: 0-1d: 4.0V / cm; 1-3d: 2.5V / cm; 3-4d: 2V / cm; 4-5d: 1V / cm;

[0132] S2: Take a sample and determine the chromium ion removal effect.

[0133] Comparative Example 2-1

[0134] The difference between this embodiment and Embodiment 12 is that it does not involve combined electro-osmosis, specifically:

[0135] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0136] A method for remediating chromium-contaminated soil using immobilized Acinetobacter venereum, comprising the following steps (parts by weight):

[0137] S1: Soil remediation test: Immobilized Acinetobacter veneris was spread as evenly as possible in chromium-contaminated soil;

[0138] S2: Samples were taken after 5 days to determine the chromium ion removal effect.

[0139] Comparative Example 2-2

[0140] The difference between this embodiment and embodiment 14 is that it does not involve combined electro-osmosis, specifically:

[0141] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0142] A method for remediating chromium-contaminated soil using immobilized Acinetobacter venereum, comprising the following steps (parts by weight):

[0143] S1: Soil remediation test: Immobilized Acinetobacter veneris was spread as evenly as possible in chromium-contaminated soil;

[0144] S2: Samples were taken after 5 days to determine the chromium ion removal effect.

[0145] Comparative Example 3-1

[0146] The difference between this embodiment and embodiment 12 is that it does not use a graded voltage gradient, specifically:

[0147] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0148] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 4.0V / cm;

[0149] S2: Take a sample and determine the chromium ion removal effect.

[0150] Comparative Example 3-2

[0151] The difference between this embodiment and embodiment 12 is that it does not use a graded voltage gradient, specifically:

[0152] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0153] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured glassy carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 2.5V / cm;

[0154] S2: Take a sample and determine the chromium ion removal effect.

[0155] Comparative Example 3-3

[0156] The difference between this embodiment and embodiment 14 is that a graded voltage gradient is not used. Specifically:

[0157] For soil contaminated with high concentrations of chromium: chromium ion concentration of 100 mg / kg:

[0158] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured glassy carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 1V / cm;

[0159] S2: Take a sample and determine the chromium ion removal effect.

[0160] Comparative Examples 3-4

[0161] The difference between this embodiment and embodiment 14 is that a graded voltage gradient is not used. Specifically:

[0162] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0163] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured vitreous carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 4.0V / cm;

[0164] S2: Take a sample and determine the chromium ion removal effect.

[0165] Comparative Examples 3-5

[0166] The difference between this embodiment and embodiment 14 is that a graded voltage gradient is not used. Specifically:

[0167] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0168] A method for remediating chromium-contaminated soil using immobilized Acinetobacter veneris combined with electro-osmosis, comprising the following steps by weight: S1: Soil remediation test: A cathode and an anode were set up, and the cathode and anode were respectively treated with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte, and allowed to stand for equilibration for 24 hours; the dual-pore structured glassy carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 2.5V / cm;

[0169] S2: Take a sample and determine the chromium ion removal effect.

[0170] Comparative Examples 3-6

[0171] The difference between this embodiment and embodiment 12 is that it does not use a graded voltage gradient, specifically:

[0172] For soil contaminated with low concentrations of chromium: chromium ion concentration of 5 mg / kg:

[0173] A method for remediating chromium-contaminated soil using immobilized Acinetobacter venereum combined with electro-osmosis, comprising the following steps (by weight):

[0174] S1: Soil remediation experiment: A cathode and an anode were set up, and the cathode and anode were respectively equipped with 0.1M citric acid monohydrate + 0.01M disodium ethylenediaminetetraacetate electrolyte and allowed to stand for equilibration for 24h; the dual-pore structured glassy carbon particles-Acinetobacter veneris immobilization carrier prepared in Example 9 were placed at the cathode, and a voltage gradient was set, 0-5d: 1V / cm;

[0175] S2: Take a sample and determine the chromium ion removal effect.

[0176] Calculate the chromium ion removal rate: Removal rate (%) = Chromium ion content in the soil after adsorption / Original chromium ion content in the soil.

[0177] Table 1. Remediation Effects of Chromium Ion Contaminated Soil

[0178] Chromium ion removal rate (%) Example 12 73.42 Example 13 70.68 Example 14 100 Example 15 100 Comparative Example 1-1 45.33 Comparative Examples 1-2 88.94 Comparative Example 2-1 59.57 Comparative Example 2-2 93.46 Comparative Example 3-1 72.17 Comparative Example 3-2 70.10 Comparative Example 3-3 63.48 Comparative Examples 3-4 100 Comparative Examples 3-5 97.33 Comparative Examples 3-6 95.24

[0179] As shown in Table 1, the method of immobilized Acinetobacter venereum combined with electro-osmosis for the remediation of chromium-contaminated soil of the present invention can achieve a 100% removal rate of chromium ions in soil with low concentrations of chromium ions, and a relatively high removal rate of 73.42% for soil with high concentrations of chromium ions. Comparative Example 1 shows that using conventional carbon particles to immobilize Acinetobacter venereum significantly reduces the removal effect of chromium ions compared to the examples. Comparative Example 3-1 shows that even without a graded voltage gradient, using 4V / cm throughout the process does not yield as good an effect as the graded voltage gradient treatment. This may be because using 4V / cm throughout the process causes unstable reflux of chromium ions in the later stages, thus reducing the removal rate.

Claims

1. A method for remediation of chromium contaminated soil by immobilized Acinetobacter venetianus combined electrokinetic permeation, characterized by, The steps are as follows in parts by weight: S1: prepare the dual-pore structure glassy carbon particles, the dual-pore structure being that the pore diameters of the pores distributed on the glassy carbon particles are 4±1 nm and 40±3 nm; S2: Preparation of OD 600 = 0.8 of A. venetianus S3: Acinetobacter venetianus immobilization: take 1 part of the dual-pore structure glassy carbon particles, add to 100 parts of LB medium, sterilize at 121℃ for 20 min, cool to room temperature, and add Acinetobacter venetianus bacterial suspension at 2% by volume, cultivate at 30℃ and 160 r / min for 24 h, and then rinse with normal saline for 2-3 times to obtain the dual-pore structure glassy carbon particle-Acinetobacter venetianus immobilized carrier; S4: soil remediation test: set the cathode and anode, and use 0.1 M citric acid monohydrate+0.01 M ethylenediaminetetraacetic acid disodium salt electrolyte for the cathode and anode respectively, and stand for balance for 24 h; place the dual-pore structure glassy carbon particle-Acinetobacter venetianus immobilized carrier at the cathode, and set a graded voltage gradient, 0-1d: 4.0 V / cm; 1-3d: 2.5 V / cm; 3-4d: 2 V / cm; 4-5d: 1 V / cm; S5: sampling and chromium ion removal effect determination; The preparation method of the dual-pore structure glassy carbon particles is as follows: S11: mix phenol, formaldehyde solution with a mass fraction of 37-40%, nano calcium carbonate, polyethylene glycol 1500 and ammonia water, stir and heat to a reaction temperature of 80℃, after reaction for 15 h, add hexamethylenetetramine, increase the temperature to 95℃ and keep the stirring rate unchanged, after 4 h, the reaction is completed; S12: after washing with water until the upper filtrate is clear, perform suction filtration, and dry in an oven at 80℃ to obtain phenolic resin particles; S13: add hexamethylenetetramine to the phenolic resin particles, and solid-mix for 1 h at ball milling, and then solidify at 200-250℃; S14: carbonization, first stage: increase the temperature to 300℃ at a temperature increasing rate of 3℃ / min; second stage: continue to increase the temperature to 800℃ at a temperature increasing rate of 1℃ / min; third stage: continue to increase the temperature to 1000℃ at a temperature increasing rate of 5℃ / min, and keep the temperature constant for 30 min; fourth stage: natural cooling; the nitrogen flow rate during the entire carbonization process is 100 mL / min; S15: activation with CO2 at 500-700℃ to obtain glassy carbon with a pore diameter of 4±1 nm; S16: wash the glassy carbon with a pore diameter of 4±1 nm with dilute hydrochloric acid to obtain the dual-pore structure glassy carbon particles. The particle size of the dual-pore structure glassy carbon particles is 100-150 μm.

2. A method for remediation of chromium contaminated soil by immobilized Acinetobacter venetianus in combination with electrokinetic permeation according to claim 1, characterized in that, The particle size of the nano calcium carbonate in S11 is 40±1 nm.

3. The method of claim 1, wherein the method is characterized by, The mass ratio of phenol, nano calcium carbonate, polyethylene glycol 1500, ammonia water and hexamethylenetetramine in S11 is: 100: (1-3): 2: 2.5: 8; the molar ratio of phenol to formaldehyde in formaldehyde solution with a mass fraction of 37-40% is 1:1.

3.

4. The method of claim 1, wherein the method is characterized by, The stirring speed in S11 is 300-350 rpm.

5. The method of remediation of chromium contaminated soil by immobilized Acinetobacter venetianus in combination with electro-osmosis according to claim 1, characterized in that, The mass ratio of phenolic resin particles to hexamethylenetetramine in S13 is 10: (0.5-2).

6. A method for remediation of chromium contaminated soil by immobilized Acinetobacter venetianus in combination with electrokinetic permeation according to claim 1, characterized in that, ​ 7. The method of claim 1, wherein the method is characterized by, The 0.1 M citric acid monohydrate + 0.01 M disodium ethylenediaminetetraacetate electrolyte in S4 needs to be replaced every 24 h.

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