CN118106336B - Treatment method for heavy metal contaminated soil - Google Patents
Treatment method for heavy metal contaminated soil Download PDFInfo
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- CN118106336B CN118106336B CN202410226018.7A CN202410226018A CN118106336B CN 118106336 B CN118106336 B CN 118106336B CN 202410226018 A CN202410226018 A CN 202410226018A CN 118106336 B CN118106336 B CN 118106336B
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- 239000002689 soil Substances 0.000 title claims abstract description 107
- 229910001385 heavy metal Inorganic materials 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000003756 stirring Methods 0.000 claims abstract description 57
- 238000002386 leaching Methods 0.000 claims abstract description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000002253 acid Substances 0.000 claims abstract description 22
- 239000002738 chelating agent Substances 0.000 claims abstract description 22
- 238000002156 mixing Methods 0.000 claims abstract description 13
- 230000000813 microbial effect Effects 0.000 claims abstract description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 42
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 40
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 32
- 229910052757 nitrogen Inorganic materials 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 19
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 16
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 16
- 238000010992 reflux Methods 0.000 claims description 16
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 15
- 150000001263 acyl chlorides Chemical class 0.000 claims description 15
- 238000001816 cooling Methods 0.000 claims description 15
- 229910052698 phosphorus Inorganic materials 0.000 claims description 15
- 239000011574 phosphorus Substances 0.000 claims description 15
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 14
- 238000001354 calcination Methods 0.000 claims description 13
- 239000001963 growth medium Substances 0.000 claims description 13
- 239000007795 chemical reaction product Substances 0.000 claims description 12
- 239000008367 deionised water Substances 0.000 claims description 12
- 229910021641 deionized water Inorganic materials 0.000 claims description 12
- 239000012065 filter cake Substances 0.000 claims description 12
- 239000010902 straw Substances 0.000 claims description 12
- 241000894006 Bacteria Species 0.000 claims description 11
- 238000001914 filtration Methods 0.000 claims description 9
- VLDPXPPHXDGHEW-UHFFFAOYSA-N 1-chloro-2-dichlorophosphoryloxybenzene Chemical compound ClC1=CC=CC=C1OP(Cl)(Cl)=O VLDPXPPHXDGHEW-UHFFFAOYSA-N 0.000 claims description 8
- 239000001888 Peptone Substances 0.000 claims description 8
- 108010080698 Peptones Proteins 0.000 claims description 8
- 235000015278 beef Nutrition 0.000 claims description 8
- PXEDJBXQKAGXNJ-QTNFYWBSSA-L disodium L-glutamate Chemical compound [Na+].[Na+].[O-]C(=O)[C@@H](N)CCC([O-])=O PXEDJBXQKAGXNJ-QTNFYWBSSA-L 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 8
- 239000000284 extract Substances 0.000 claims description 8
- 229910052588 hydroxylapatite Inorganic materials 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 235000013923 monosodium glutamate Nutrition 0.000 claims description 8
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical compound [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 claims description 8
- 235000019319 peptone Nutrition 0.000 claims description 8
- 239000011780 sodium chloride Substances 0.000 claims description 8
- 229940073490 sodium glutamate Drugs 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- 238000001291 vacuum drying Methods 0.000 claims description 8
- 235000007164 Oryza sativa Nutrition 0.000 claims description 7
- 240000008042 Zea mays Species 0.000 claims description 7
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 claims description 7
- 235000002017 Zea mays subsp mays Nutrition 0.000 claims description 7
- 235000005822 corn Nutrition 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 7
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 7
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 7
- UHZYTMXLRWXGPK-UHFFFAOYSA-N phosphorus pentachloride Chemical compound ClP(Cl)(Cl)(Cl)Cl UHZYTMXLRWXGPK-UHFFFAOYSA-N 0.000 claims description 7
- 235000009566 rice Nutrition 0.000 claims description 7
- 238000002390 rotary evaporation Methods 0.000 claims description 5
- 241000193755 Bacillus cereus Species 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 4
- 241000589517 Pseudomonas aeruginosa Species 0.000 claims description 4
- 241000191973 Staphylococcus xylosus Species 0.000 claims description 4
- 241001607911 Stenotrophomonas rhizophila Species 0.000 claims description 4
- 238000004090 dissolution Methods 0.000 claims description 4
- 239000012153 distilled water Substances 0.000 claims description 4
- 238000004108 freeze drying Methods 0.000 claims description 4
- 239000002054 inoculum Substances 0.000 claims description 4
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 claims description 4
- 238000007873 sieving Methods 0.000 claims description 4
- 230000001954 sterilising effect Effects 0.000 claims description 4
- 238000007605 air drying Methods 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 240000007594 Oryza sativa Species 0.000 claims 2
- 239000002609 medium Substances 0.000 claims 1
- 244000005700 microbiome Species 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 7
- 230000009920 chelation Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 42
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 229910052586 apatite Inorganic materials 0.000 description 7
- 150000002500 ions Chemical class 0.000 description 7
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical compound [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 7
- 241000209094 Oryza Species 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 239000003480 eluent Substances 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 3
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 description 3
- LWIHDJKSTIGBAC-UHFFFAOYSA-K potassium phosphate Substances [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 description 3
- 238000005067 remediation Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000000967 suction filtration Methods 0.000 description 3
- XIEPJMXMMWZAAV-UHFFFAOYSA-N cadmium nitrate Chemical compound [Cd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XIEPJMXMMWZAAV-UHFFFAOYSA-N 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 2
- RLJMLMKIBZAXJO-UHFFFAOYSA-N lead nitrate Chemical compound [O-][N+](=O)O[Pb]O[N+]([O-])=O RLJMLMKIBZAXJO-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical group [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 2
- 108010078791 Carrier Proteins Proteins 0.000 description 1
- 102000014914 Carrier Proteins Human genes 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 150000008064 anhydrides Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000001506 calcium phosphate Substances 0.000 description 1
- 229910000389 calcium phosphate Inorganic materials 0.000 description 1
- 235000011010 calcium phosphates Nutrition 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 230000004060 metabolic process Effects 0.000 description 1
- 239000002207 metabolite Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000008635 plant growth Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
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- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/10—Reclamation of contaminated soil microbiologically, biologically or by using enzymes
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Soil Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Biotechnology (AREA)
- General Health & Medical Sciences (AREA)
- Microbiology (AREA)
- Molecular Biology (AREA)
- Mycology (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to the technical field of soil treatment, in particular to a treatment method for heavy metal contaminated soil, which is used for solving the problem that the existing repair method for heavy metal contaminated soil has an unsatisfactory repair effect on contaminated soil with various heavy metals; adding a polycarboxylic acid chelating agent into clear water to prepare a leaching solution, adding crushed polluted soil into the leaching solution, stirring for reaction, centrifuging to remove the leaching solution to obtain leached soil, and uniformly mixing the leached soil and microbial doped biochar to obtain treated heavy metal polluted soil; the treatment method provided by the invention can effectively remove heavy metals in soil through the combination of various means such as chelation, leaching, microorganism restoration, plant restoration and the like, and meanwhile, the method can not cause secondary pollution to the environment, and has the advantages of simplicity and convenience in operation, obvious effect, low cost and the like, and has a good application prospect.
Description
Technical Field
The invention relates to the technical field of soil treatment, in particular to a treatment method for heavy metal contaminated soil.
Background
At present, the repair method of heavy metal contaminated soil mainly comprises physical repair, chemical repair, biological repair and other methods, and compared with other repair methods, the chemical repair method has the advantages of stable and thorough treatment effect and the like, and the soil leaching can rapidly remove pollutants from the soil, so that the treatment of high-concentration contaminated soil can be completed in a short time, and the treatment cost is relatively low, thereby being particularly suitable for the treatment of severe and small-area contaminated soil. In the prior art, citric acid is generally used as eluent for leaching soil, but the restoration effect of the soil polluted by the coexistence of various heavy metals is not ideal, so how to comprehensively remove the heavy metals in the soil polluted by the coexistence of various heavy metals is a technical problem to be solved. Therefore, the development of a treatment method for heavy metal contaminated soil has great practical significance.
Disclosure of Invention
In order to overcome the technical problems, the invention aims to provide a treatment method for heavy metal contaminated soil, which comprises the following steps: the method comprises the steps of adding a polycarboxylic acid chelating agent into clear water to prepare a leaching solution, air-drying heavy metal contaminated soil, crushing, sieving to obtain crushed contaminated soil, adding the crushed contaminated soil into the leaching solution, stirring for reaction, centrifuging to remove the leaching solution to obtain leached soil, uniformly mixing the leached soil with microbial doped biochar to obtain treated heavy metal contaminated soil, and solving the problem that the existing heavy metal contaminated soil remediation method is unsatisfactory in remediation effect on contaminated soil coexisting with various heavy metals.
The aim of the invention can be achieved by the following technical scheme:
the treatment method for the heavy metal contaminated soil comprises the following steps:
Step one: adding a polycarboxylic acid chelating agent into clear water to prepare leaching solution with the molar concentration of 0.15-1.5 mol/L;
Step two: air-drying and crushing the heavy metal contaminated soil, and sieving the crushed heavy metal contaminated soil with a 100-200-mesh sieve to obtain crushed contaminated soil;
step three: crushing polluted soil according to a solid-to-liquid ratio of 1:3-10, adding the mixture into the leaching solution, stirring and reacting for 3-4 hours at the temperature of 25-30 ℃ and the stirring speed of 350-400r/min, and centrifuging to remove the leaching solution to obtain leaching soil;
Step four: leaching soil and microbial doped biochar according to the mass ratio of 15-30:1, uniformly mixing to obtain treated heavy metal contaminated soil.
As a further scheme of the invention: the polycarboxylic acid chelating agent is prepared by the following steps:
Step A1: adding pyromellitic dianhydride, phosphorus pentachloride and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring and reacting for 20-30min under the conditions of 25-30 ℃ and stirring speed of 350-400r/min, heating to reflux, continuing stirring and reacting for 40-50h, cooling the reaction product to room temperature after the reaction, and removing the solvent by rotary evaporation to obtain an acyl chloride intermediate;
Step A2: adding sodium glutamate, deionized water and methylene dichloride into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring and reacting for 20-30min under the conditions of the temperature of-5-0 ℃ and the stirring speed of 350-400r/min, adding an acyl chloride intermediate, continuously stirring and reacting for 5-10min, adding a sodium hydroxide solution to adjust the pH value to 9-10, heating to reflux, continuously stirring and reacting for 4-5h, cooling the reaction product to room temperature after the reaction is finished, rotationally evaporating to remove the solvent, washing with absolute ethyl alcohol for 2-3 times, adding into a hydrochloric acid solution, continuously stirring and reacting for 1-2h, vacuum filtering, placing a filter cake into a vacuum drying box, and drying for 6-8h under the conditions of the temperature of 55-60 ℃ to obtain the polycarboxylic acid chelating agent.
As a further scheme of the invention: the dosage ratio of the pyromellitic dianhydride, the phosphorus pentachloride and the N, N-dimethylformamide in the step A1 is 10 mmol: 22-25 mmol: 50-60mL.
As a further scheme of the invention: the dosage ratio of the sodium glutamate, deionized water, dichloromethane, acyl chloride intermediate and hydrochloric acid solution in the step A2 is 42-45 mmol: 10-12mL:65-70mL:10 mmol: 35-40mL, wherein the mass fraction of the sodium hydroxide solution is 10-15%, and the molar concentration of the hydrochloric acid solution is 1.0-1.5 mol/L.
As a further scheme of the invention: the microbial doped biochar is prepared by the following steps:
Step B1: mixing corn straw and rice straw, crushing, adding hydroxyapatite, placing in a muffle furnace, introducing nitrogen for protection, calcining for 20-30min at 300-320 ℃, heating to 500-520 ℃ for calcining for 1-1.5h, heating to 700-750 ℃ for calcining for 2-2.5h, and cooling with the furnace to obtain apatite-doped biochar;
Step B2: adding apatite-doped biochar, potassium dihydrogen phosphate and deionized water into a three-neck flask with a stirrer and a thermometer, stirring at 25-30 ℃ and stirring speed of 350-400r/min for reaction for 20-30min, heating to 60-65 ℃ for continuous stirring for reaction for 2-3h, cooling the reaction product to room temperature after the reaction, vacuum filtering, placing the filter cake into a vacuum drying oven, and drying at 55-60 ℃ for 3-5h to obtain apatite-doped phosphorus-based biochar;
Step B3: adding apatite-doped phosphorus-based biochar into a culture medium, sterilizing at 121 ℃ for 20-30min, inoculating mixed bacteria with 10% of inoculum size, placing the mixed bacteria at 25-30 ℃ for shake culture at 150-200r/min for 18-20h, vacuum-filtering, and freeze-drying a filter cake to obtain the microorganism-doped biochar.
As a further scheme of the invention: the dosage ratio of the corn straw to the rice straw to the hydroxyapatite in the step B1 is 20-50g:10g:0.2-1g.
As a further scheme of the invention: the dosage ratio of the apatite doped biochar, the monopotassium phosphate and the deionized water in the step B2 is 10g:2-5g:60-70mL.
As a further scheme of the invention: the usage ratio of the apatite doped phosphorus-based biochar and the culture medium in the step B3 is 0.3-0.5g:100mL.
As a further scheme of the invention: the preparation method of the culture medium in the step B3 comprises the following steps:
adding beef extract, peptone and sodium chloride into a beaker, adding distilled water for dissolution, and then adjusting the pH to 7-7.5 with hydrochloric acid solution or sodium hydroxide solution.
As a further scheme of the invention: the 1L culture medium contains 3g of beef extract, 10g of peptone and 5g of sodium chloride, and the molar concentration of the hydrochloric acid solution or the sodium hydroxide solution is1 mol/L.
As a further scheme of the invention: the mixed bacteria in the step B3 are a mixture of stenotrophomonas rhizophila, bacillus cereus, pseudomonas aeruginosa and staphylococcus xylosus according to any proportion.
The invention has the beneficial effects that:
According to the treatment method for the heavy metal contaminated soil, the polycarboxylic acid chelating agent is added into clear water to prepare the leacheate, the heavy metal contaminated soil is crushed after being air-dried, then the crushed contaminated soil is sieved, the crushed contaminated soil is added into the leacheate to be stirred and reacted, the leacheate is centrifugally removed to obtain the leacheate, and the leacheate and the microbial doped biochar are uniformly mixed to obtain treated heavy metal contaminated soil; the treatment method provided by the invention can effectively remove heavy metals in soil through the combination of various means such as chelation, leaching, microorganism restoration, plant restoration and the like, and meanwhile, the method can not cause secondary pollution to the environment, and has the advantages of simplicity and convenience in operation, obvious effect, low cost and the like, and has a good application prospect.
In the process of treating heavy metal contaminated soil, firstly preparing a polycarboxylic acid chelating agent, firstly utilizing pyromellitic dianhydride and phosphorus pentachloride to react, thereby converting two anhydride groups on the pyromellitic dianhydride into four acyl chloride groups to obtain an acyl chloride intermediate, then utilizing the acyl chloride intermediate and sodium glutamate to react, reacting the acyl chloride groups on the acyl chloride intermediate with amino groups on the sodium glutamate, and then acidizing to form eight carboxyl groups to obtain the polycarboxylic acid chelating agent; the molecular structure of the polycarboxylic acid chelating agent contains a large number of carboxyl groups so that the polycarboxylic acid chelating agent can carry out chelating reaction with heavy metal ions, and the reaction effect is sufficient, so that the heavy metal ions in soil can be fully reacted to form a large number of stable heavy metal chelates, and the heavy metal chelates are removed along with leacheate; the polycarboxylic acid chelating agent is used for effectively removing heavy metals in soil based on chelating and leaching means;
In the process of treating heavy metal contaminated soil, preparing microorganism doped biochar, firstly calcining corn straw, rice straw and hydroxyapatite serving as raw materials to form apatite doped biochar, then treating the apatite doped biochar by potassium dihydrogen phosphate to enable a large amount of phosphorus elements to be doped in the apatite doped biochar, obtaining apatite doped phosphorus based biochar, and finally loading mixed bacteria into the apatite doped phosphorus based biochar to obtain microorganism doped biochar; after the microbial doped biochar is mixed with heavy metal contaminated soil, a large number of micropores are formed on the biochar to form gas channels, so that sufficient oxygen can be provided for microorganisms, the microorganisms are promoted to reproduce and grow, and the microorganisms and metabolites thereof are as follows: the products such as polysaccharide, cellulose, protein, DNA and the like can react with heavy metal ions to enable the heavy metal ions to be adsorbed, the hydroxyapatite is rich in hydroxyl and calcium phosphate groups, calcium phosphate ions can be exchanged with the heavy metal ions to form a complex, the complex has higher adsorption capacity on the heavy metal ions, a large amount of phosphorus elements can be provided for plants together with the doped phosphorus elements to promote plant growth, and the heavy metal ions can be transported into tissues and organs by the plants through related transport proteins and then converted into gaseous substances through metabolic processes to be diffused into the atmosphere; the microorganism doped biochar is used for effectively removing heavy metals in soil based on adsorption treatment and bioremediation technology.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1:
This embodiment is a method for preparing a polycarboxylic acid chelating agent, comprising the steps of:
Step A1: adding 10 mmol of pyromellitic dianhydride, 22 mmol of phosphorus pentachloride and 50mLN, N-dimethylformamide into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring at 25 ℃ and stirring speed of 350r/min for reaction for 20min, heating to reflux, continuing stirring for reaction for 40h, cooling the reaction product to room temperature after the reaction, and removing the solvent by rotary evaporation to obtain an acyl chloride intermediate;
Step A2: adding 42mmo L of sodium glutamate, 10mL of deionized water and 65mL of dichloromethane into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser, introducing nitrogen for protection, stirring and reacting for 20min under the condition that the temperature is-5 ℃ and the stirring speed is 350r/min, adding 10mmo L of acyl chloride intermediate, continuously stirring and reacting for 5min, adding 10% sodium hydroxide solution for regulating the pH to 9, heating to reflux, continuously stirring and reacting for 4h, cooling the reaction product to room temperature after the reaction, rotationally evaporating to remove the solvent, washing for 2 times with absolute ethyl alcohol, continuously stirring and reacting for 1h in 35mL of hydrochloric acid solution with the molar concentration of 1.0 mol/L, vacuum filtering, placing the filter cake in a vacuum drying box, and drying for 6h under the condition that the temperature is 55 ℃ to obtain the polycarboxylic acid chelating agent.
Example 2:
This embodiment is a method for preparing a polycarboxylic acid chelating agent, comprising the steps of:
Step A1: adding 10 mmol of pyromellitic dianhydride, 25 mmol of phosphorus pentachloride and 60mLN, N-dimethylformamide into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring at the temperature of 30 ℃ and the stirring speed of 400r/min for reaction for 30min, heating to reflux, continuing stirring for reaction for 50h, cooling the reaction product to room temperature after the reaction is finished, and removing the solvent by rotary evaporation to obtain an acyl chloride intermediate;
Step A2: 45mmo of sodium glutamate, 12mL of deionized water and 70mL of dichloromethane are added into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser, nitrogen is introduced for protection, stirring is carried out for 30min under the condition of the temperature of 0 ℃ and the stirring rate of 400r/min, then 10mmo of acyl chloride intermediate is added for continuous stirring for reaction for 10min, then 15% sodium hydroxide solution with the mass fraction of 15% is added for regulating the pH value to be 10, then the temperature is increased to the condition of reflux for continuous stirring for reaction for 5h, the reaction product is cooled to room temperature after the reaction is ended, then the solvent is removed by rotary evaporation, the solution is washed for 3 times by absolute ethyl alcohol, then the solution is added into 40mL of hydrochloric acid solution with the molar concentration of 1.5 mol/L for continuous stirring for 2h, then vacuum suction filtration is carried out, the filter cake is placed in a vacuum drying box for 8h under the condition of the temperature of 60 ℃ to obtain the polycarboxylic acid chelating agent.
Example 3:
the embodiment is a preparation method of microorganism doped biochar, comprising the following steps:
Step B1: mixing 20g of corn straw and 10g of rice straw, crushing, adding 0.2g of hydroxyapatite, placing in a muffle furnace, introducing nitrogen for protection, calcining for 20min at 300 ℃, heating to 500 ℃, calcining for 1h, heating to 700 ℃ and calcining for 2h, and cooling with the furnace to obtain the apatite-doped biochar;
Step B2: adding 10g of apatite-doped biochar, 2g of monopotassium phosphate and 60mL of deionized water into a three-neck flask provided with a stirrer and a thermometer, stirring and reacting for 20min at the temperature of 25 ℃ and the stirring speed of 350r/min, then heating to 60 ℃ and continuously stirring and reacting for 2h, cooling the reaction product to room temperature after the reaction is finished, then carrying out vacuum suction filtration, placing a filter cake into a vacuum drying box, and drying for 3h at the temperature of 55 ℃ to obtain apatite-doped phosphorus-based biochar;
Step B3: adding 0.3g of apatite-doped phosphorus-based biochar into 100mL of culture medium, sterilizing at 121 ℃ for 20min, inoculating mixed bacteria with 10% of inoculum size, placing at 25 ℃ for shake culture for 18h at 150r/min, vacuum-filtering, and freeze-drying a filter cake to obtain microorganism-doped biochar;
the preparation method of the culture medium comprises the following steps:
Adding beef extract, peptone and sodium chloride into a beaker, adding distilled water for dissolution, and then adjusting the pH to 7 by using hydrochloric acid solution or sodium hydroxide solution.
The 1L culture medium contains 3g of beef extract, 10g of peptone and 5g of sodium chloride, and the molar concentration of the hydrochloric acid solution or the sodium hydroxide solution is 1 mol/L.
The mixed bacteria are a mixture of stenotrophomonas rhizophila, bacillus cereus, pseudomonas aeruginosa and staphylococcus xylosus according to any proportion.
Example 4:
the embodiment is a preparation method of microorganism doped biochar, comprising the following steps:
Step B1: mixing 50g of corn straw and 10g of rice straw, crushing, adding 1g of hydroxyapatite, placing in a muffle furnace, introducing nitrogen for protection, calcining for 30min at 320 ℃, heating to 520 ℃, calcining for 1.5h, heating to 750 ℃, calcining for 2.5h, and cooling with the furnace to obtain the apatite-doped biochar;
Step B2: adding 10g of apatite-doped biochar, 5g of monopotassium phosphate and 70mL of deionized water into a three-neck flask with a stirrer and a thermometer, stirring and reacting for 30min at the temperature of 30 ℃ and the stirring speed of 400r/min, then heating to 65 ℃ and continuously stirring and reacting for 3h, cooling the reaction product to room temperature after the reaction is finished, then carrying out vacuum suction filtration, placing a filter cake into a vacuum drying box, and drying for 5h at the temperature of 60 ℃ to obtain apatite-doped phosphorus-based biochar;
step B3: adding 0.5g of apatite-doped phosphorus-based biochar into 100mL of culture medium, sterilizing at 121 ℃ for 30min, inoculating mixed bacteria with 10% of inoculum size, placing at 30 ℃ for shake culture for 20h at 200r/min, vacuum-filtering, and freeze-drying a filter cake to obtain microorganism-doped biochar;
the preparation method of the culture medium comprises the following steps:
Adding beef extract, peptone and sodium chloride into a beaker, adding distilled water for dissolution, and then adjusting the pH to 7 by using hydrochloric acid solution or sodium hydroxide solution.
The 1L culture medium contains 3g of beef extract, 10g of peptone and 5g of sodium chloride, and the molar concentration of the hydrochloric acid solution or the sodium hydroxide solution is 1 mol/L.
The mixed bacteria are a mixture of stenotrophomonas rhizophila, bacillus cereus, pseudomonas aeruginosa and staphylococcus xylosus according to any proportion.
Example 5:
The embodiment is a treatment method for heavy metal contaminated soil, comprising the following steps:
Step one: adding the polycarboxylic acid chelating agent from example 1 to clear water to prepare an eluent with the molar concentration of 0.15 mol/L;
step two: drying and crushing the heavy metal polluted soil, and sieving the crushed heavy metal polluted soil with a 100-mesh sieve to obtain crushed polluted soil;
Step three: crushing polluted soil according to a solid-to-liquid ratio of 1:3 adding the mixture into the leaching solution, stirring and reacting for 3 hours at the temperature of 25 ℃ and the stirring speed of 350r/min, and centrifuging to remove the leaching solution to obtain leaching soil;
Step four: leaching soil and microbial doped biochar from the example 3 according to a mass ratio of 30:1, uniformly mixing to obtain treated heavy metal contaminated soil.
Example 6:
The embodiment is a treatment method for heavy metal contaminated soil, comprising the following steps:
Step one: adding the polycarboxylic acid chelating agent from example 2 to clear water to prepare an eluent with the molar concentration of 1.5 mol/L;
step two: the heavy metal polluted soil is crushed after being air-dried, and then is sieved by a 200-mesh sieve, so that crushed polluted soil is obtained;
Step three: crushing polluted soil according to a solid-to-liquid ratio of 1:10 is added into the leaching solution, stirred and reacted for 4 hours under the conditions that the temperature is 30 ℃ and the stirring speed is 400r/min, and then the leaching solution is centrifugally removed to obtain leaching soil;
Step four: leaching soil and microbial doped biochar from the example 4 according to a mass ratio of 15:1, uniformly mixing to obtain treated heavy metal contaminated soil.
Comparative example 1:
the comparative example is a treatment method for heavy metal contaminated soil, comprising the following steps:
step one: adding citric acid into clear water to prepare leaching solution with the molar concentration of 1.5 mol/L;
step two: the heavy metal polluted soil is crushed after being air-dried, and then is sieved by a 200-mesh sieve, so that crushed polluted soil is obtained;
Step three: crushing polluted soil according to a solid-to-liquid ratio of 1:10 is added into the leaching solution, stirred and reacted for 4 hours under the conditions of the temperature of 30 ℃ and the stirring speed of 400r/min, and then the leaching solution is centrifugally removed, so that the treated heavy metal contaminated soil is obtained.
Comparative example 2:
the comparative example is a treatment method for heavy metal contaminated soil, comprising the following steps:
step one: adding citric acid into clear water to prepare leaching solution with the molar concentration of 1.5 mol/L;
step two: the heavy metal polluted soil is crushed after being air-dried, and then is sieved by a 200-mesh sieve, so that crushed polluted soil is obtained;
Step three: crushing polluted soil according to a solid-to-liquid ratio of 1:10 is added into the leaching solution, stirred and reacted for 4 hours under the conditions that the temperature is 30 ℃ and the stirring speed is 400r/min, and then the leaching solution is centrifugally removed to obtain leaching soil;
Step four: leaching soil and microbial doped biochar from the example 4 according to a mass ratio of 15:1, uniformly mixing to obtain treated heavy metal contaminated soil.
Comparative example 3:
the comparative example is a treatment method for heavy metal contaminated soil, comprising the following steps:
Step one: adding the polycarboxylic acid chelating agent from example 2 to clear water to prepare an eluent with the molar concentration of 1.5 mol/L;
step two: the heavy metal polluted soil is crushed after being air-dried, and then is sieved by a 200-mesh sieve, so that crushed polluted soil is obtained;
Step three: crushing polluted soil according to a solid-to-liquid ratio of 1:10 is added into the leaching solution, stirred and reacted for 4 hours under the conditions that the temperature is 30 ℃ and the stirring speed is 400r/min, and then the leaching solution is centrifugally removed to obtain leaching soil;
Step four: leaching soil and apatite-doped biochar from example 4 according to a mass ratio of 15:1, uniformly mixing to obtain treated heavy metal contaminated soil.
Wherein, heavy metal contaminated soil is homemade in the performance test process:
Preparing 1L of mixed solution containing Cu(NO3)2、N i(NO3)2、Pb(NO3)2、Cd(NO3)2 and ZnC L 2, wherein the theoretical concentration of Cu, N i, pb, cd and Zn is 2000mg/L, 1000mg/L and 1000mg/L respectively, mixing the mixed solution with 1kg of clean soil, placing the mixture in a ventilation place for natural aging for 2 months after manual stirring, and obtaining self-made heavy metal contaminated soil, and detecting the physicochemical properties of heavy metals in the self-made heavy metal contaminated soil, wherein the detection results are shown as follows:
the treatment in examples 5 to 6 and comparative examples 1 to 3 was completed to naturally age the heavy metal contaminated soil for 30d, and then the physicochemical properties of the heavy metal in the self-made heavy metal contaminated soil were examined, and the examination results are shown below:
referring to the data in the table above, according to the comparison between examples 5-6 and comparative examples 1-3, it can be known that the use of the polycarboxylic acid chelating agent and the microbial doped biochar can effectively remove heavy metals in heavy metal contaminated soil, and realize soil remediation of the heavy metal contaminated soil.
In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing is merely illustrative and explanatory of the invention, as various modifications and additions may be made to the particular embodiments described, or in a similar manner, by those skilled in the art, without departing from the scope of the invention or exceeding the scope of the invention as defined in the claims.
Claims (6)
1. The treatment method for the heavy metal contaminated soil is characterized by comprising the following steps of:
Step one: adding a polycarboxylic acid chelating agent into clear water to prepare leaching solution with the molar concentration of 0.15-1.5 mol/L;
Step two: air-drying and crushing the heavy metal contaminated soil, and sieving the crushed heavy metal contaminated soil with a 100-200-mesh sieve to obtain crushed contaminated soil;
step three: crushing polluted soil according to a solid-to-liquid ratio of 1:3-10, adding the mixture into the leaching solution, stirring and reacting for 3-4 hours at the temperature of 25-30 ℃ and the stirring speed of 350-400r/min, and centrifuging to remove the leaching solution to obtain leaching soil;
Step four: leaching soil and microbial doped biochar according to the mass ratio of 15-30:1, uniformly mixing to obtain treated heavy metal contaminated soil;
Wherein the polycarboxylic acid chelating agent is prepared by the following steps:
step A1: adding pyromellitic dianhydride, phosphorus pentachloride and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring and reacting for 20-30min under the conditions of 25-30 ℃ and stirring speed of 350-400r/min, heating to reflux, continuing stirring and reacting for 40-50h, cooling the reaction product to room temperature after the reaction, and removing the solvent by rotary evaporation to obtain an acyl chloride intermediate; the dosage ratio of the pyromellitic dianhydride to the phosphorus pentachloride to the N, N-dimethylformamide is 10mmol:22-25mmol:50-60mL;
Step A2: adding sodium glutamate, deionized water and methylene dichloride into a three-neck flask provided with a stirrer, a thermometer, a nitrogen inlet pipe and a reflux condenser pipe, introducing nitrogen for protection, stirring and reacting for 20-30min under the conditions of the temperature of-5-0 ℃ and the stirring speed of 350-400r/min, adding an acyl chloride intermediate, continuously stirring and reacting for 5-10min, adding a sodium hydroxide solution to adjust the pH value to 9-10, heating to reflux, continuously stirring and reacting for 4-5h, cooling the reaction product to room temperature after the reaction is finished, rotationally evaporating to remove the solvent, washing with absolute ethyl alcohol for 2-3 times, adding into a hydrochloric acid solution, continuously stirring and reacting for 1-2h, vacuum filtering, placing a filter cake into a vacuum drying box, and drying for 6-8h under the conditions of the temperature of 55-60 ℃ to obtain a polycarboxylic acid chelating agent; the dosage ratio of the sodium glutamate, deionized water, dichloromethane, acyl chloride intermediate and hydrochloric acid solution is 42-45mmol:10-12mL:65-70mL:10mmol:35-40mL, wherein the mass fraction of the sodium hydroxide solution is 10-15%, and the molar concentration of the hydrochloric acid solution is 1.0-1.5mol/L;
The microbial doped biochar is prepared by the following steps:
Step B1: mixing corn straw and rice straw, crushing, adding hydroxyapatite, placing in a muffle furnace, introducing nitrogen for protection, calcining for 20-30min at 300-320 ℃, heating to 500-520 ℃ for calcining for 1-1.5h, heating to 700-750 ℃ for calcining for 2-2.5h, and cooling with the furnace to obtain apatite-doped biochar;
Step B2: adding apatite-doped biochar, potassium dihydrogen phosphate and deionized water into a three-neck flask with a stirrer and a thermometer, stirring at 25-30 ℃ and stirring speed of 350-400r/min for reaction for 20-30min, heating to 60-65 ℃ for continuous stirring for reaction for 2-3h, cooling the reaction product to room temperature after the reaction, vacuum filtering, placing the filter cake into a vacuum drying oven, and drying at 55-60 ℃ for 3-5h to obtain apatite-doped phosphorus-based biochar;
step B3: adding apatite-doped phosphorus-based biochar into a culture medium, sterilizing at 121 ℃ for 20-30min, inoculating mixed bacteria with 10% of inoculum size, placing the mixed bacteria at 25-30 ℃ for shake culture at 150-200r/min for 18-20h, vacuum-filtering, and freeze-drying a filter cake to obtain microorganism-doped biochar; the mixed bacteria are a mixture of stenotrophomonas rhizophila, bacillus cereus, pseudomonas aeruginosa and staphylococcus xylosus according to any proportion.
2. The method for treating heavy metal contaminated soil according to claim 1, wherein the dosage ratio of the corn stalk, the rice stalk and the hydroxyapatite in the step B1 is 20-50g:10g:0.2-1g.
3. The method for treating heavy metal contaminated soil according to claim 1, wherein the apatite-doped biochar, potassium dihydrogen phosphate and deionized water in the step B2 are used in an amount ratio of 10g:2-5g:60-70mL.
4. The method for treating heavy metal contaminated soil according to claim 1, wherein the apatite-doped phosphorus-based biochar and the culture medium in the step B3 are used in an amount ratio of 0.3-0.5g:100mL.
5. The method for treating heavy metal contaminated soil according to claim 1, wherein said medium in step B3 is prepared by:
adding beef extract, peptone and sodium chloride into a beaker, adding distilled water for dissolution, and then adjusting the pH to 7-7.5 with hydrochloric acid solution or sodium hydroxide solution.
6. The method for treating heavy metal contaminated soil according to claim 5, wherein 1L of the culture medium contains 3g of beef extract, 10g of peptone and 5g of sodium chloride, and the molar concentration of the hydrochloric acid solution or the sodium hydroxide solution is 1mol/L.
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| CN109772868A (en) * | 2019-03-07 | 2019-05-21 | 新昌县以琳环保科技有限公司 | The ecological environment of soil restorative procedure for preventing and treating heavy metal pollution |
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