CN111534305A - In-situ repair medicament and preparation method and application thereof - Google Patents
In-situ repair medicament and preparation method and application thereof Download PDFInfo
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- CN111534305A CN111534305A CN202010389791.7A CN202010389791A CN111534305A CN 111534305 A CN111534305 A CN 111534305A CN 202010389791 A CN202010389791 A CN 202010389791A CN 111534305 A CN111534305 A CN 111534305A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/40—Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C2101/00—In situ
Abstract
The invention provides an in-situ remediation medicament and a preparation method and application thereof, and relates to the technical field of environmental pollution remediation. The in-situ repairing medicament provided by the invention comprises modified biotite loaded nano zero-valent zinc, modified hectorite loaded nano zero-valent zinc, starch and edible oil; the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is loaded on the middle layer of the modified biotite; the modified biotite is obtained by modifying biotite with alkyl-substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol; the nanometer zero-valent zinc in the modified hectorite-loaded nanometer zero-valent zinc is loaded on the middle layer of the modified hectorite; the modified hectorite is obtained by modifying hectorite by alkyl-substituted ammonium bromide, azodiisobutyronitrile, acrylic acid-2-ethylhexyl ester and n-octanol. The in-situ remediation agent provided by the invention has good dispersibility, realizes high-efficiency degradation of the halogenated organic pollutants in the adsorption state and the free state, and also provides nutrient elements for microbial reaction in soil.
Description
Technical Field
The invention relates to the technical field of environmental pollution remediation, in particular to an in-situ remediation medicament and a preparation method and application thereof.
Background
Halogenated organic pollutants are a common soil pollutant, and generally comprise organic chlorine solvents, petroleum hydrocarbons and derivatives thereof, and the like, which are easy to leak into soil during transportation, storage and use of chemical products. Besides being not easy to dissolve in water, the water-soluble organic fertilizer can be maintained in the underground environment for decades due to the characteristic of difficult biodegradation, and causes continuous potential harm to human health and ecological environment.
An aeration zone is a zone below the ground above the submergible surface, the soil voids not being filled with water, containing air, wherein water is predominantly present in the form of gaseous water, adsorbed water, and capillary water. The first time the pollutant enters the underground environment is the aeration zone, so the pollutant plays an important role in the whole soil environment including the underground water pollution process. Under the influence of geological features, halogenated organic pollutants in the aeration zone mainly take a soil adsorption state as a main component, and exist in multiphase forms of a volatile state, a residual state, a free state and the like, and the halogenated saturation degrees of the pollutants are different, so that the halogenated organic pollutants are difficult to be perfectly treated by common repair technologies such as advanced oxidation, soil vapor extraction, plant/microorganism repair and the like.
The nano material is a material which has at least one dimension in a nano scale range in three dimensions or is formed by taking the nano material as a basic unit. Because of its intermediate mesoscopic region between macroscopic conventional fines and microscopic clusters of atoms, it exhibits several unique properties, one of which is a surface effect. The surface effect refers to the property change caused by the sharp increase of the ratio of the surface atoms to the total number of atoms of the nanoparticle as the particle diameter becomes smaller. Studies have shown that as particle diameter decreases, the percentage of surface atoms to total atoms increases dramatically; at the same time, the surface area and surface energy of the nanoparticles are also rapidly increased. Therefore, the nano zero-valent zinc-based repair material has great potential in the field of pollution control.
However, the main problems of the nano materials in the process of treating the pollutants are: the enormous surface energy causes agglomeration between particles, which affects its reducing ability, service life and migration ability in porous media (see T.Phenrat, T.C.Long, G.V.Lowry, B.Veronsi.partial oxidation (imaging) and surface modification of the reactivity of nano-sized regulated iron. environmental science and Technology,2009,43: 195-200.). Therefore, the preparation of the supported nano-material with stable performance and high reactivity by adopting a proper carrier material and a supporting method is one of the development directions for solving the problem. For example, the removal capacity of the nitrobenzene is far stronger than that of the nitrobenzene of the nano zero-valent iron and the organic bentonite with the same content when the nano zero-valent iron is loaded on the modified organic bentonite (see: Hu Liu Jiang, Li Yi Min. organic bentonite loaded with nano iron for removing nitrobenzene in wastewater. environmental science bulletin, 2008,28(6): 1107-1112.). However, the existing supported nano zero-valent iron cannot realize the degradation of halogenated organic pollutants in both an adsorption state and a free state.
Disclosure of Invention
In view of the above, the present invention provides an in-situ remediation agent, and a preparation method and an application thereof, and the in-situ remediation agent provided by the present invention can simultaneously achieve efficient degradation of adsorbed-state and free-state halogenated organic pollutants.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides an in-situ repairing medicament, which comprises modified biotite loaded nano zero-valent zinc, modified hectorite loaded nano zero-valent zinc, starch and edible oil;
the ratio of the total mass of the modified biotite loaded nanometer zero-valent zinc, the modified hectorite loaded nanometer zero-valent zinc and the starch to the volume of the edible oil is 400-600 g: 1L;
the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is loaded on the middle layer of the modified biotite; the modified biotite is obtained by modifying biotite with a first organic modifier, wherein the first organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol;
the nanometer zero-valent zinc in the modified hectorite-loaded nanometer zero-valent zinc is loaded on the middle layer of the modified hectorite; the modified hectorite is obtained by modifying hectorite with a second organic modifier, wherein the second organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, 2-ethylhexyl acrylate and n-octanol.
Preferably, the mass ratio of the modified biotite loaded nanometer zero-valent zinc to the modified hectorite loaded nanometer zero-valent zinc to the starch is (5-7): (10-12): (1-5).
Preferably, the particle size of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc and the particle size of the nano zero-valent zinc in the modified hectorite-loaded nano zero-valent zinc are 0.5-2 nm independently.
Preferably, the loading amounts of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc and the nano zero-valent zinc in the modified hectorite-loaded nano zero-valent zinc are independently 2-4 wt%.
Preferably, the preparation method of the modified biotite loaded nano zero-valent zinc comprises the following steps:
mixing biotite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated biotite;
mixing the zinc ion saturated biotite and a first organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated biotite; the first organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol;
saturating the modified zinc ion with biotite and Ce (BH) in protective atmosphere4)3Mixing, and carrying out reduction reaction to obtain the modified biotite loaded nano zero-valent zinc.
Preferably, the ratio of the mass of the alkyl-substituted ammonium bromide to the mass of the azobisisobutyronitrile to the volume of the methyl methacrylate to the volume of the n-octanol is (5 to 10) g: (0.5-1) g: 10mL of: (25-40) mL.
Preferably, the preparation method of the modified hectorite loaded nano zero-valent zinc comprises the following steps:
mixing hectorite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated hectorite;
mixing the zinc ion saturated hectorite and a second organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated hectorite; the second organic modifier comprises alkyl substituted ammonium bromide, azobisisobutyronitrile, 2-ethylhexyl acrylate and n-octanol;
in a protective atmosphere, the modified zinc ion saturated hectorite and NaBH4Mixing, and carrying out reduction reaction to obtain the modified hectorite loaded nano zero-valent zinc.
Preferably, the ratio of the mass of the alkyl-substituted ammonium bromide, the mass of the azobisisobutyronitrile, the volume of the 2-ethylhexyl acrylate and the volume of the n-octanol is (5 to 10) g: (0.5-1) g: 30mL of: (25-40) mL.
The invention provides a preparation method of the in-situ repair medicament in the technical scheme, which comprises the following steps:
mixing the modified biotite loaded nano zero-valent zinc, the modified hectorite loaded nano zero-valent zinc, starch and edible oil to obtain the in-situ repairing medicament.
The invention also provides the application of the in-situ remediation medicament in the technical scheme or the in-situ remediation medicament prepared by the preparation method in the technical scheme in-situ remediation of halogenated organic pollutants.
The invention provides an in-situ repairing medicament, which comprises a solid component and edible oil; the concentration of the solid component is 400-600 g/L; the solid component comprises modified biotite loaded nano zero-valent zinc, modified hectorite loaded nano zero-valent zinc and starch. The invention takes the modified biotite or the modified hectorite as the carrier of the nano zero-valent zinc, avoids the agglomeration of nano zero-valent zinc functional material units, and improves the dispersibility and the degradation capability to organic pollutants. The modified biotite loaded nano zero-valent zinc and the modified hectorite loaded nano zero-valent zinc are used as functional components, so that the high-efficiency degradation of adsorption-state and free-state halogenated organic pollutants which are difficult to degrade is realized, wherein the modified biotite loaded nano zero-valent zinc mainly degrades the free-state halogenated organic pollutants, the interlayer charge ratio of the biotite is higher (generally 1 unit of chemical formula charge) so that the layers of the biotite are not easy to separate, the free-state halogenated organic pollutants do not contain water, and the modified biotite loaded nano zero-valent zinc contains water in the middle layer of the modified biotite (the water is positioned around the nano zero-valent zinc), so that the water requirement for degrading the free-state halogenated organic pollutants can be met, the nano zero-valent zinc can be fully contacted with the free-state halogenated organic pollutants, and the high-efficiency degradation of the free-state halogenated organic pollutants is realized; the modified hectorite loaded nano zero-valent zinc mainly degrades adsorbed halogenated organic pollutants, the interlayer charge ratio of the hectorite is low (generally 0.2-0.5 unit of chemical formula charge), so that layers of the hectorite are easy to separate, the interlayer distance is large, the nano zero-valent zinc in the middle layer of the modified hectorite loaded nano zero-valent zinc is in full contact with the adsorbed halogenated organic pollutants entering the interlayer of the modified hectorite loaded nano zero-valent zinc, and the efficient degradation of the adsorbed halogenated organic pollutants is realized. The nano zero-valent zinc loaded on the biotite or the hectorite has high activity, and the functional material can be quickly inactivated when the nano zero-valent zinc is stored in water; the starch and the edible oil can ensure that the modified biotite loaded with the nano zero-valent zinc and the modified hectorite loaded with the nano zero-valent zinc are better compatible with the environment of the soil-enveloped gas zone, and the halogenated organic pollutants in two forms of a free state and an adsorption state are synchronously degraded; meanwhile, the fertilizer can also provide nutrient elements for the microbial reaction in soil. Compared with the dissolved halogenated organic pollutants, the adsorbed and free halogenated organic pollutants have lower contact probability with the solid in-situ remediation medicament and are difficult to degrade.
The preparation method provided by the invention is simple to operate and suitable for industrial production.
Detailed Description
The invention provides an in-situ repairing medicament, which comprises modified biotite loaded nano zero-valent zinc, modified hectorite loaded nano zero-valent zinc, starch and edible oil;
the ratio of the total mass of the modified biotite loaded nanometer zero-valent zinc, the modified hectorite loaded nanometer zero-valent zinc and the starch to the volume of the edible oil is 400-600 g: 1L;
the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is loaded on the middle layer of the modified biotite; the modified biotite is obtained by modifying biotite with a first organic modifier, wherein the first organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol;
the nanometer zero-valent zinc in the modified hectorite-loaded nanometer zero-valent zinc is loaded on the middle layer of the modified hectorite; the modified hectorite is obtained by modifying hectorite with a second organic modifier, wherein the second organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, 2-ethylhexyl acrylate and n-octanol.
In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.
In the invention, the ratio of the total mass of the modified biotite loaded nanometer zero-valent zinc, the modified hectorite loaded nanometer zero-valent zinc and the starch to the volume of the edible oil is 450-580 g: 1L, more preferably 500-550 g: 1L of the compound.
In the invention, the mass ratio of the modified biotite loaded nanometer zero-valent zinc to the modified hectorite loaded nanometer zero-valent zinc to the starch is preferably (5-7): (10-12): (1-5), more preferably (5.5-6.5): (10.5-11.5): (1.5-4.5), most preferably (5.5-6): (11-11.5): (2-4).
In the invention, the loading amount of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is preferably 2-4 wt%, and more preferably 2.5-3.5 wt%. In the invention, the particle size of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is preferably 0.5-2 nm, and more preferably 1-1.5 nm. The high interlayer charge ratio (generally 1 unit of chemical formula charge) of the biotite makes the layers difficult to separate; the free-state halogenated organic pollutant does not contain water, the first organic modifier can inhibit the lamella separation of the biotite, wherein the molecular chain of methyl methacrylate is short, the moisture contained between the biotite layers cannot be extruded out in the cross-linking reaction process, the channel inlet of the biotite lamella cannot be blocked, the pollutant can enter the layers to be in contact reaction with the zero-valent zinc, and the first organic modifier can also ensure that the modified biotite loaded with the nano zero-valent zinc can be suspended in a system containing edible oil and starch without agglomeration. The modified biotite loaded nano zero-valent zinc in the modified biotite loaded nano zero-valent zinc has water in the modified biotite intermediate layer, so that the modified biotite loaded nano zero-valent zinc can be brought into the free halogenated organic pollutants, the water requirement for degradation of the free halogenated organic pollutants is met, the nano zero-valent zinc is fully contacted with the free halogenated organic pollutants, and efficient degradation of the free halogenated organic pollutants is realized.
In the invention, the preparation method of the modified biotite loaded nano zero-valent zinc preferably comprises the following steps:
mixing biotite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated biotite;
mixing the zinc ion saturated biotite and a first organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated biotite; the first organic modifier preferably comprises alkyl-substituted ammonium bromide, azobisisobutyronitrile, methyl methacrylate, and n-octanol;
saturating the modified zinc ion with biotite and Ce (BH) in protective atmosphere4)3Mixing, and carrying out reduction reaction to obtain the modified biotite loaded nano zero-valent zinc.
According to the invention, biotite, soluble zinc salt and water are mixed, the pH value of the obtained mixed solution is adjusted to 3-4, and ion exchange reaction is carried out to obtain zinc ion saturated biotite.
In the invention, the soluble zinc salt is preferably one or more of zinc nitrate, zinc sulfate and zinc chloride, and is more preferably zinc chloride. In the present invention, when the soluble zinc salt is a different kind of zinc salt, the mass ratio of the different kind of zinc salt is not particularly limited, and any ratio may be used. In the present invention, the water is preferably deionized water.
The biotite is not particularly limited in the present invention, and any biotite known to those skilled in the art may be used. In the present invention, the ratio of the mass of biotite to the amount of soluble zinc salt substance is preferably (10 to 100) g: 0.1mol, more preferably (12 to 20) g: 0.1mol, most preferably (14 to 18) g: 0.1 mol. In the present invention, the mass-to-water volume ratio of the biotite is preferably (10 to 100) g: 500mL, more preferably (10 to 20) g: 500mL, most preferably (12-18) g: 500 mL.
In the present invention, the mixing order of the biotite, the soluble zinc salt and water is preferably a first mixing of the biotite and water followed by a second mixing with addition of the soluble zinc salt. In the present invention, the first mixing and the second mixing are preferably stirring mixing, and the stirring mixing speed in the present invention is not particularly limited, and a stirring speed known to those skilled in the art may be used. In the invention, the time for the first mixing is preferably 5-10 min; the time for the second mixing is not particularly limited, and the raw materials can be uniformly mixed.
In the present invention, the pH of the mixed solution is more preferably 3 to 3.5, and still more preferably 3.2. The acid used for adjusting the pH of the mixed solution obtained in the present invention is preferably an inorganic acid, and the kind of the inorganic acid is not particularly limited in the present invention, and inorganic acids known to those skilled in the art may be used, specifically, hydrochloric acid or sulfuric acid; the concentration of the acid is not particularly limited, and the pH value can be adjusted to 3-4. The pH value is adjusted to 3-4 so as to ensure that zinc ions exist in a free state.
In the invention, the temperature of the ion exchange reaction is preferably 15-30 ℃, and more preferably 18-25 ℃; the time of the ion exchange reaction is preferably 15-20 h, and more preferably 18 h. In the invention, zinc ions are adsorbed on the negative potential in the biotite in the ion exchange reaction process, and metal cations such as potassium, calcium, sodium, magnesium and the like in the biotite are exchanged.
After the ion exchange reaction is completed, the invention preferably further comprises the step of carrying out solid-liquid separation on the system of the ion exchange reaction. The solid-liquid separation mode is not particularly limited, and a solid-liquid separation mode known to those skilled in the art can be adopted, specifically centrifugal separation; the conditions for the centrifugal separation are not particularly limited in the present invention, and the solid product and the liquid component can be separated.
After the solid-liquid separation, the present invention preferably repeats the ion exchange reaction of the obtained solid product. In the present invention, the number of the ion exchange reactions is preferably 3. In the invention, zinc ions are adsorbed on the negative potential in the biotite in the ion exchange reaction process, and all the negative potential in the biotite is saturated by the zinc ions after 3 times of ion exchange reaction.
After zinc ion saturated biotite is obtained, mixing the zinc ion saturated biotite and a first organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated biotite; the first organic modifier preferably comprises alkyl-substituted ammonium bromide, azobisisobutyronitrile, methyl methacrylate, and n-octanol.
The protective atmosphere in the present invention is not particularly limited, and those known to those skilled in the art may be used, specifically, nitrogen or argon.
In the invention, the mass-to-volume ratio of the alkyl-substituted ammonium bromide, the azobisisobutyronitrile, the methyl methacrylate and the n-octanol is preferably (5-10) g: (0.5-1) g: 10mL of: (25-40) mL, more preferably (6-9) g: (0.6-0.9) g: 10mL of: (28-38) mL, most preferably (7-8) g: (0.7-0.8) g: 10mL of: (30-35) mL. In the present invention, the alkyl-substituted ammonium bromide preferably comprises tetramethylammonium bromide and/or phenyltrimethylammonium bromide; when the alkyl substituted ammonium bromide is tetramethyl ammonium bromide and phenyl trimethyl ammonium bromide, the mass ratio of the tetramethyl ammonium bromide to the phenyl trimethyl ammonium bromide is not particularly limited, and any ratio can be adopted. In the present invention, the first organic modifier functions as: (1) the biotite is ensured to be capable of suspending in a system containing edible oil and starch without agglomeration; (2) can inhibit lamellar separation of biotite; (3) the methyl methacrylate has a short molecular chain, so that moisture contained in the biotite layers cannot be extruded in the crosslinking reaction process, and the channel inlet of the biotite layers cannot be blocked, so that the pollutants cannot enter the contact reaction between the layers and the zero-valent zinc.
The biotite has higher interlayer charge ratio (generally 1 unit of chemical formula charge), so that the layers are not easy to separate; the free-state halogenated organic pollutants do not contain water, and the water in the modified biotite intermediate layer in the modified biotite loaded nanometer zero-valent zinc can be brought into the free-state halogenated organic pollutants, so that the water requirement of the free-state halogenated organic pollutants is met, and the efficient degradation of the free-state halogenated organic pollutants is realized.
In the invention, the temperature of the crosslinking reaction is 60-70 ℃, more preferably 62-68 ℃, and most preferably 65 ℃; the time of the crosslinking reaction is preferably 10-15 h, and more preferably 12 h. During the crosslinking reaction, methyl methacrylate is crosslinked to the surface of the zinc ion saturated biotite.
In the invention, the reaction system after the crosslinking reaction is directly subjected to the subsequent reduction reaction without post-treatment.
After the modified zinc ion saturated biotite is obtained, the modified zinc ion saturated biotite and Ce (BH) are added4)3Mixing, and carrying out reduction reaction to obtain the modified biotite loaded nano zero-valent zinc.
The protective atmosphere in the present invention is not particularly limited, and those known to those skilled in the art may be used, specifically, nitrogen or argon.
For Ce (BH) in the invention4)3The amount of the modified zinc ion saturated biotite is not particularly limited, and the modified zinc ion saturated biotite can be completely reduced into part zinc4)3The ratio of the amounts of substances is preferably 10 g: (0.25-0.4) mol. The invention uses Ce (BH)4)3As a reducing agent, reducing zinc ions among the modified zinc ion saturated biotite layers into zero-valent zinc, balancing negative charges among the biotite layers by Ce ions, and further strengthening the acting force of the Ce ions and the biotite layers because the hydrated layers are very thin and are close to the biotite layers, thereby inhibiting the lamella separation of the modified biotite loaded with nano zero-valent zinc; the free-state halogenated organic pollutants do not contain water, and the modified biotite intermediate layer in the modified biotite loaded nanometer zero-valent zinc contains water, so that the water requirement for degrading the free-state halogenated organic pollutants can be met, the nanometer zero-valent zinc can be fully contacted with the free-state halogenated organic pollutants, and the efficient degradation of the free-state halogenated organic pollutants is realized.
In the invention, the temperature of the reduction reaction is preferably room temperature, and the temperature of the reduction reaction is preferably 4-8 min, and more preferably 5 min. In the invention, in the reduction reaction process, zinc ions among the modified zinc ion saturated biotite layers are reduced to zero-valent zinc.
After the reduction reaction is finished, the invention preferably further comprises the steps of carrying out solid-liquid separation on the system of the reduction reaction, and sequentially carrying out water washing, alcohol washing and drying on the obtained solid components to obtain the modified biotite loaded nano zero-valent zinc. The solid-liquid separation mode is not particularly limited, and a solid-liquid separation mode known to those skilled in the art can be adopted, specifically, filtration or centrifugal separation; in the present invention, the conditions for the filtration or the centrifugal separation are not particularly limited, and the separation of the solid component and the liquid component can be achieved. In the invention, the washing is preferably deionized water washing, and the amount of water used for washing and the number of times of washing are not particularly limited, so that hydrophilic substances can be removed completely. In the present invention, the alcohol used for the alcohol washing is preferably methanol or ethanol, and the amount of the alcohol used for the alcohol washing and the number of times of the alcohol washing are not particularly limited, and it is sufficient to remove the substances dissolved in the alcohol. The drying temperature and time are not particularly limited, and water and alcohol in the modified biotite loaded nano zero-valent zinc can be completely removed.
In the invention, the loading amount of the nano zero-valent zinc in the modified hectorite-loaded nano zero-valent zinc is preferably 2-4 wt%, and more preferably 2.5-3.5%. In the invention, the particle size of the nanometer zero-valent zinc in the modified hectorite-loaded nanometer zero-valent zinc is preferably 0.5-2 nm, and more preferably 1-1.5 nm. The interlayer charge ratio of the hectorite is lower (generally 0.2-0.5 unit chemical formula charge), so that layers of the hectorite are easy to separate, and the interlayer spacing is large; the second organic modifier can promote lamella separation of hectorite, wherein the molecular chain of 2-ethylhexyl acrylate is longer and is crosslinked to the surface of the hectorite in the crosslinking reaction process, so that the modified hectorite loaded with nano zero-valent zinc can be better contacted with soil, the contact probability of the microscopically modified hectorite loaded with nano zero-valent zinc and the adsorbed halogenated organic pollutants in the soil is increased, and the efficient degradation of the adsorbed halogenated organic pollutants is realized; and after the second organic modifier modifies the hectorite, the modified hectorite loaded with the nano zero-valent zinc can be suspended in a system containing edible oil and starch without agglomeration. The nanometer zero-valent zinc positioned in the middle layer of the modified hectorite loaded nanometer zero-valent zinc is fully contacted with the adsorption-state halogenated organic pollutants entering the middle layer of the modified hectorite loaded nanometer zero-valent zinc, so that the high-efficiency degradation of the adsorption-state halogenated organic pollutants is realized.
In the invention, the preparation method of the modified hectorite loaded nano zero-valent zinc comprises the following steps:
mixing hectorite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated hectorite;
mixing the zinc ion saturated hectorite and a second organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated hectorite; the second organic modifier preferably comprises alkyl-substituted ammonium bromide, azobisisobutyronitrile, 2-ethylhexyl acrylate, and n-octanol;
mixing the modified zinc ion saturated hectorite and NaBH4Mixing, and carrying out reduction reaction to obtain the modified hectorite loaded nano zero-valent zinc.
According to the invention, hectorite, soluble zinc salt and water are mixed, the pH value of the obtained mixed solution is adjusted to 3-4, and ion exchange reaction is carried out to obtain zinc ion saturated hectorite.
In the invention, the soluble zinc salt is preferably one or more of zinc nitrate, zinc sulfate and zinc chloride, and is more preferably zinc chloride. In the present invention, when the soluble zinc salt is a different kind of zinc salt, the mass ratio of the different kind of zinc salt is not particularly limited, and any ratio may be used. In the present invention, the water is preferably deionized water. In the present invention, the ratio of the mass of the hectorite to the amount of the soluble zinc salt substance is preferably (10 to 100) g: 0.2mol, more preferably (12 to 20) g: 0.2mol, most preferably (14 to 18) g: 0.2 mol. In the invention, the ratio of the mass of the hectorite to the volume of water is preferably (10-100) g: 500mL, more preferably (10 to 20) g: 500mL, most preferably (12-18) g: 500 mL.
In the present invention, the order of mixing the hectorite, the soluble zinc salt and water is preferably that the hectorite and water are mixed for the third time and then the soluble zinc salt is added for the fourth time. In the present invention, the third mixing and the fourth mixing are preferably stirring mixing, and the stirring mixing speed in the present invention is not particularly limited, and a stirring speed known to those skilled in the art may be used. In the invention, the time for the third mixing is preferably 5-10 min; in the present invention, the time for the fourth mixing is not particularly limited, and the raw materials may be mixed uniformly.
In the present invention, the pH of the mixed solution is more preferably 3.4 to 3.6, and still more preferably 3.5. The acid used for adjusting the pH of the mixed solution obtained in the present invention is preferably an inorganic acid, and the kind of the inorganic acid is not particularly limited in the present invention, and inorganic acids known to those skilled in the art may be used, specifically, hydrochloric acid or sulfuric acid; the concentration of the acid is not particularly limited, and the pH value can be adjusted to 3-4. The pH value is adjusted to 3-4 so as to ensure that zinc ions exist in a free state.
In the invention, the temperature of the ion exchange reaction is preferably 15-30 ℃, and more preferably 18-25 ℃; the time of the ion exchange reaction is preferably 15-20 h, and more preferably 18 h. In the present invention, zinc ions are adsorbed at a negative potential in the hectorite during the ion exchange reaction.
After the ion exchange reaction, the present invention preferably further comprises performing solid-liquid separation on the system of the ion exchange reaction. The solid-liquid separation mode is not particularly limited, and a solid-liquid separation mode known to those skilled in the art can be adopted, specifically centrifugal separation; the conditions for the centrifugal separation are not particularly limited in the present invention, and the solid product and the liquid component can be separated.
After the solid-liquid separation, the present invention preferably repeats the ion exchange reaction of the obtained solid product. In the present invention, the number of the ion exchange reactions is preferably 3. In the invention, zinc ions are adsorbed on the negative potential in the hectorite in the ion exchange reaction process, and all the negative potential in the hectorite is saturated by the zinc ions after 3 times of ion exchange reaction.
After obtaining the zinc ion saturated hectorite, mixing the zinc ion saturated hectorite with a second organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated hectorite; the second organic modifier preferably comprises alkyl-substituted ammonium bromide, azobisisobutyronitrile, 2-ethylhexyl acrylate, and n-octanol.
In the present invention, the first and second of the first organic modifier and the second organic modifier are not particularly limited in order to distinguish the two organic modifiers.
The protective atmosphere in the present invention is not particularly limited, and those known to those skilled in the art may be used, specifically, nitrogen or argon.
In the invention, the mass-to-volume ratio of the alkyl-substituted ammonium bromide, the azobisisobutyronitrile, the 2-ethylhexyl acrylate and the n-octanol is preferably (5-10) g: (0.5-1) g: 30mL of: (25-40) mL, more preferably (6-9) g: (0.6-0.9) g: 10mL of: (28-38) mL, most preferably (7-8) g: (0.7-0.8) g: 10mL of: (30-35) mL. In the present invention, the alkyl-substituted ammonium bromide preferably comprises tetramethylammonium bromide and/or phenyltrimethylammonium bromide; when the alkyl substituted ammonium bromide is tetramethyl ammonium bromide and phenyl trimethyl ammonium bromide, the mass ratio of the tetramethyl ammonium bromide to the phenyl trimethyl ammonium bromide is not particularly limited, and any ratio can be adopted. In the present invention, the second organic modifier functions as: (1) the hectorite can be suspended in a system containing edible oil and starch, and is not agglomerated; (2) can promote lamella separation of hectorite; (3) the molecular chain of the acrylic acid-2-ethylhexyl ester is longer, and the acrylic acid-2-ethylhexyl ester is crosslinked to the surface of the hectorite in the crosslinking reaction process, so that the modified hectorite loaded with the nano zero-valent zinc can be better contacted with soil, the contact probability of the microcosmically modified hectorite loaded with the nano zero-valent zinc and the adsorbed halogenated organic pollutants in the soil is increased, and the high-efficiency degradation of the adsorbed halogenated organic pollutants is realized.
In the invention, the temperature of the crosslinking reaction is 60-70 ℃, more preferably 62-68 ℃, and most preferably 65 ℃; the time of the crosslinking reaction is preferably 10-15 h, and more preferably 12 h. During the crosslinking reaction, 2-ethylhexyl acrylate is crosslinked to the surface of zinc ion saturated hectorite.
In the invention, the reaction system after the crosslinking reaction is directly subjected to the subsequent reduction reaction without post-treatment.
After obtaining the modified zinc ion saturated hectorite, the invention leads the modified zinc ion saturated hectorite and NaBH4Mixing, and carrying out reduction reaction to obtain the modified hectorite loaded nano zero-valent zinc.
The protective atmosphere in the present invention is not particularly limited, and those known to those skilled in the art may be used, specifically, nitrogen or argon.
For NaBH in the present invention4The dosage of the modified zinc ion saturated hectorite is not particularly limited, and the zinc ion in the modified zinc ion saturated hectorite can be completely reduced into part zinc4The ratio of the amounts of substances is preferably 10 g: (0.25-0.4) mol. The invention uses NaBH4As a reducing agent, zinc ions among modified zinc ion saturated hectorite layers are reduced to zero-valent zinc, negative charges among the hectorite layers are balanced by Na ions, the lamella separation of the modified hectorite loaded with nano zero-valent zinc is promoted, the interlayer spacing is large, the nano zero-valent zinc in the modified hectorite loaded nano zero-valent zinc interlayer is in full contact with adsorbed halogenated organic pollutants entering the modified hectorite loaded nano zero-valent zinc layers, and the efficient degradation of the adsorbed halogenated organic pollutants is realized.
In the invention, the temperature of the reduction reaction is preferably room temperature, and the temperature of the reduction reaction is preferably 4-8 min, and more preferably 5 min. In the invention, in the reduction reaction process, zinc ions between the modified zinc ion saturated hectorite layers are reduced to zero-valent zinc.
After the reduction reaction, the invention preferably further comprises the steps of carrying out solid-liquid separation on the system of the reduction reaction, and sequentially carrying out water washing, alcohol washing and drying on the obtained solid components to obtain the modified hectorite loaded nano zero-valent zinc. The solid-liquid separation mode is not particularly limited, and a solid-liquid separation mode known to those skilled in the art can be adopted, specifically, filtration or centrifugal separation; in the present invention, the conditions for the filtration or the centrifugal separation are not particularly limited, and the separation of the solid component and the liquid component can be achieved. In the invention, the washing is preferably deionized water washing, and the amount of water used for washing and the number of times of washing are not particularly limited, so that hydrophilic substances can be removed completely. In the present invention, the alcohol used for the alcohol washing is preferably methanol or ethanol, and the amount of the alcohol used for the alcohol washing and the number of times of the alcohol washing are not particularly limited, and it is sufficient to remove the substances dissolved in the alcohol. The drying temperature and time are not particularly limited, and water and alcohol in the modified hectorite loaded nano zero-valent zinc can be completely removed.
In the invention, the preparation of the modified biotite loaded nano zero-valent zinc and the preparation of the modified hectorite loaded nano zero-valent zinc are not in sequence.
The starch is not particularly limited, and may be starch known to those skilled in the art, such as one or more of mung bean starch, tapioca starch, sweet potato starch, wheat starch, water chestnut starch, lotus root starch and corn starch. The starch can ensure that the modified biotite loaded nano zero-valent zinc and the modified hectorite loaded nano zero-valent zinc are better compatible with the environment of the soil-enclosed air zone, and halogenated organic pollutants in two forms of a free state and an adsorption state are synchronously degraded; meanwhile, the fertilizer can also provide nutrient elements for the microbial reaction in soil.
The in-situ repairing medicament provided by the invention comprises edible oil. The type of the edible oil is not particularly limited, and the edible oil known to those skilled in the art may be used, specifically, one or more of rapeseed oil, peanut oil, hemp seed oil, corn oil, olive oil, camellia oil, palm oil, sunflower seed oil, soybean oil, sesame oil, linseed oil (also called linseed oil), grape seed oil, walnut oil and peony seed oil. In the invention, the activity of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc and the modified hectorite-loaded nano zero-valent zinc is very high, and the functional material can be quickly inactivated when the modified biotite-loaded nano zero-valent zinc and the modified hectorite-loaded nano zero-valent zinc are stored in water; the starch and the edible oil can ensure that the modified biotite loaded with the nano zero-valent zinc and the modified hectorite loaded with the nano zero-valent zinc are better compatible with the environment of the soil-enveloped gas zone, and the halogenated organic pollutants in two forms of a free state and an adsorption state are synchronously degraded; meanwhile, the fertilizer can also provide nutrient elements for the microbial reaction in soil. Compared with the dissolved halogenated organic pollutants, the adsorbed and free halogenated organic pollutants have lower contact probability with the solid in-situ remediation medicament and are difficult to degrade.
The invention provides a preparation method of the in-situ repair medicament in the technical scheme, which comprises the following steps:
mixing the modified biotite loaded nano zero-valent zinc, the modified hectorite loaded nano zero-valent zinc, starch and edible oil to obtain the in-situ repairing medicament.
The mixing method of the invention is not particularly limited, and the raw materials can be uniformly mixed. The order of mixing is not particularly limited, and the raw materials can be uniformly mixed. In the present invention, the mixing is preferably performed at room temperature.
The invention also provides the application of the in-situ remediation medicament in the technical scheme or the in-situ remediation medicament prepared by the preparation method in the technical scheme in-situ remediation of halogenated organic pollutants.
In the present invention, the halogenated organic contaminant is preferably a halogenated organic contaminant present in the aeration zone of the soil; the halogenated organic contaminants preferably comprise free-state halogenated organic contaminants and/or adsorbed-state halogenated organic contaminants. In the invention, the halogenated organic pollutant preferably comprises one or more of decachlorobiphenyl, decabromodiphenyl ether, tetrabromobisphenol A, tetrachloroethylene and pentachlorophenol.
In the invention, in order to simulate the degradation effect of the in-situ remediation agent on free-state and adsorption-state halogenated organic pollutants in the aeration zone polluted soil, the simulated aeration zone polluted soil is prepared, the in-situ remediation agent is added into the simulated aeration zone polluted soil, and the concentration of the halogenated organic pollutants in the simulated aeration zone polluted soil before and after degradation is tested, wherein the degradation rate of the halogenated organic pollutants is equal to the initial concentration of the halogenated organic pollutants/the final concentration of the halogenated organic pollutants multiplied by 100%.
In the invention, the preparation method of the simulated aeration zone contaminated soil comprises the following steps: adding the free-state halogenated organic pollutants and/or the adsorption-state halogenated organic pollutants into the soil, and uniformly mixing to obtain the simulated aeration zone polluted soil.
The dosage ratio of the halogenated organic pollutant to the in-situ remediation agent is not particularly limited, and is preferably adjusted according to actual conditions.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) Preparation of modified biotite loaded nano zero-valent zinc
Mixing 50g of biotite and 2.5L of deionized water under stirring for 5min, and adding 1mol of ZnCl2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated biotite;
stirring and mixing 1.8L of n-octanol, 360g of tetramethylammonium bromide, 36g of azobisisobutyronitrile and 720mL of methyl methacrylate for 30min to obtain a first organic modifier; stirring and mixing 50g of zinc ion saturated biotite 2.5L of first organic modifier uniformly, and carrying out modification reaction for 12h at 60 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated biotite;
50g of the modified zinc ion-saturated biotite and 1.25mol of Ce (BH) were added under a nitrogen atmosphere4)3Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain the modified biotite loaded nano zero-valent zinc.
(2) Preparation of modified hectorite loaded nano zero-valent zinc
120g of hectorite and 6L of deionized water are stirred and mixed for 5min, and 2.4mol of ZnCl is added2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3.5, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated hectorite;
stirring and mixing 2.75L of n-octanol, 550g of tetramethylammonium bromide, 55g of azobisisobutyronitrile and 3.3L of 2-ethylhexyl acrylate for 45min to obtain a second organic modifier; stirring and mixing 120g of zinc ion saturated hectorite and 6L of second organic modifier uniformly, and carrying out modification reaction for 12 hours at 60 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated hectorite;
120g of the modified zinc ion saturated hectorite and 30mol of NaBH in a nitrogen atmosphere4Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain modified hectorite loaded nano zero-valent zinc;
the step (1) and the step (2) have no sequence.
(3) Preparation of in-situ repairing medicament
And (3) uniformly mixing 50g of modified biotite loaded nano zero-valent zinc, 120g of modified hectorite loaded nano zero-valent zinc, 30g of starch and 500mL of edible oil to obtain the in-situ repairing medicament.
(4) Applications of
Placing the decachlorobiphenyl and the decabromodiphenyl ether in soil, and uniformly mixing to obtain simulated aeration-contaminated soil, wherein the initial concentration of the decachlorobiphenyl is 20ppm, and the initial concentration of the decabromodiphenyl ether is 40 ppm. Injecting 100mL of in-situ remediation agent at the positions of 0.25m, 0.5m and 0.75m of the depth of the simulated aeration zone contaminated soil, and performing degradation reaction for one week to obtain a detection result: the final concentration of the decachlorobiphenyl is 17ppm, and the degradation rate of the decachlorobiphenyl is 85 percent; the final concentration of the decabromodiphenyl oxide is 11.2ppm, and the degradation rate of the decabromodiphenyl oxide is 72 percent, which shows that the in-situ remediation agent provided by the invention has high degradation rate on decachlorodiphenyl and decabromodiphenyl oxide.
Example 2
(1) Preparation of modified biotite loaded nano zero-valent zinc
420g of biotite and 10.5L of deionized water are stirred and mixed for 5min, and 4.2mol of ZnCl are added2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated biotite;
stirring and mixing 16.8L of n-octanol, 4.2kg of tetramethylammonium bromide, 420g of azobisisobutyronitrile and 4.2L of methyl methacrylate for 30min to obtain a first organic modifier; uniformly stirring and mixing 420g of zinc ion saturated biotite and 21L of first organic modifier, and carrying out modification reaction for 12 hours at 70 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated biotite;
420g of the modified zinc ion-saturated biotite and 16.8mol of Ce (BH) in a nitrogen atmosphere4)3Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain the modified biotite loaded nano zero-valent zinc.
(2) Preparation of modified hectorite loaded nano zero-valent zinc
600g of hectorite and 15L of deionized water are stirred and mixed for 5min, and 6mol of ZnCl is added2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3.5, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated hectorite;
stirring and mixing 17.2L of n-octanol, 4.3kg of tetramethylammonium bromide, 430g of azobisisobutyronitrile and 12.9L of 2-ethylhexyl acrylate for 45min to obtain a second organic modifier; uniformly stirring and mixing 600g of zinc ion saturated hectorite and 30L of second organic modifier, and carrying out modification reaction for 12 hours at 70 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated hectorite;
600g of the modified zinc ion saturated hectorite and 24mol of NaBH are added in a nitrogen atmosphere4Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain the modified lithium soapStone-loaded nano zero-valent zinc;
the step (1) and the step (2) have no sequence.
(3) Preparation of in-situ repairing medicament
420g of modified biotite loaded nano zero-valent zinc, 600g of modified hectorite loaded nano zero-valent zinc, 180g of starch and 2L of edible oil are mixed uniformly to obtain the in-situ repairing medicament.
(4) Applications of
Placing tetrabromobisphenol A and tetrachloroethylene in soil, and uniformly mixing to obtain simulated aeration-contaminated soil, wherein the initial concentration of tetrabromobisphenol A is 30ppm, and the initial concentration of tetrachloroethylene is 10 ppm. Injecting 600mL of in-situ remediation agent at the positions of the simulated aeration zone contaminated soil with the depths of 0.25m, 0.5m and 0.75m respectively, and detecting the result after 5 days of degradation reaction: the final concentration of tetrabromobisphenol A is 2.1ppm, and the degradation rate is 93 percent; the final concentration of the ethylene tetrachloride is 3.2ppm, and the degradation rate of the ethylene tetrachloride is 68%, which shows that the in-situ repair medicament provided by the invention has high degradation rate to tetrabromobisphenol A and ethylene tetrachloride.
Example 3
(1) Preparation of modified biotite loaded nano zero-valent zinc
Mixing 4.5kg of biotite and 150L of deionized water under stirring for 5min, and adding 60mol of ZnCl2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated biotite;
stirring and mixing 169L of n-octanol, 39.4kg of phenyltrimethylammonium bromide, 3.94g of azobisisobutyronitrile and 57L of methyl methacrylate for 30min to obtain a first organic modifier; uniformly stirring and mixing 4.5kg of zinc ion saturated biotite and 225L of first organic modifier, and carrying out modification reaction for 12 hours at 65 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated biotite;
4.5kg of the modified zinc ion saturated biotite and 135mol of Ce (BH) in a nitrogen atmosphere4)3Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially carrying out separation on the obtained solid componentsWashing the mica with water, washing with ethanol and drying to obtain the modified biotite loaded nano zero-valent zinc.
(2) Preparation of modified hectorite loaded nano zero-valent zinc
Stirring 8.7kg of hectorite and 290L of deionized water, mixing for 5min, and adding 116mol of ZnCl2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3.5, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated hectorite;
stirring and mixing 254L n-octanol, 50.75kg phenyl trimethyl ammonium bromide, 5.075kg azobisisobutyronitrile and 217.5L 2-ethylhexyl acrylate for 45min to obtain a second organic modifier; stirring and mixing 8.7kg of zinc ion saturated hectorite and 435L of second organic modifier uniformly, and carrying out modification reaction for 12 hours at 60 ℃ in a nitrogen atmosphere under the stirring condition to obtain modified zinc ion saturated hectorite;
8.7kg of the modified zinc ion saturated hectorite and 261mol NaBH in a nitrogen atmosphere4Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain modified hectorite loaded nano zero-valent zinc;
the step (1) and the step (2) have no sequence.
(3) Preparation of in-situ repairing medicament
4.05kg of modified biotite loaded nano zero-valent zinc, 8.7kg of modified hectorite loaded nano zero-valent zinc, 2.25kg of starch and 30L of edible oil are mixed uniformly to obtain the in-situ repairing medicament.
(4) Applications of
Placing pentachlorophenol and tetrachloroethylene in soil, and uniformly mixing to obtain the simulated aeration zone contaminated soil, wherein the initial concentration of the pentachlorophenol is 82ppm, and the initial concentration of the tetrachloroethylene is 171 ppm. Injecting 500mL of in-situ remediation agent at the positions of the simulated aeration zone contaminated soil with the depths of 0.25m, 0.5m and 0.75m respectively, and performing degradation reaction for 19 days to obtain a detection result: the final concentration of the ethylene tetrachloride is 25.6ppm, and the degradation rate is 85%; the final concentration of the pentachlorophenol is 7.3ppm, and the degradation rate of the pentachlorophenol is 91%, which shows that the in-situ repair medicament provided by the invention has high degradation rate to the pentachlorophenol and the tetrachloroethylene.
Comparative example 1
An in situ healing formulation was prepared according to the method of example 1, differing from example 1 in that:
in the step (1), zinc ion saturated biotite is not modified, but is directly subjected to reduction reaction to obtain biotite loaded nano zero-valent zinc;
in the step (2), zinc ion saturated hectorite is not modified, but is directly subjected to reduction reaction to obtain the hectorite loaded with nano zero-valent zinc;
the in-situ repairing agent in the step (3) consists of: 50g of biotite loaded nano zero-valent zinc, 120g of hectorite loaded nano zero-valent zinc, 30g of starch and 500mL of edible oil.
By adopting the application method of the step (4) in the embodiment 1, the detection result is as follows: it can be seen from example 1 and comparative example 1 that compared with the in-situ remediation agent prepared in comparative example 1, the in-situ remediation agent prepared in example 1 has a 1.9-fold degradation rate on decachlorobiphenyl and a 1.3-fold degradation rate on decabromodiphenyl ether. Compared with unmodified biotite loaded nanometer zero-valent zinc and hectorite loaded nanometer zero-valent zinc, the zinc ion saturated biotite modified organic repairing agent has the advantages that zinc ion saturated biotite is modified by the first organic modifier, zinc ion saturated hectorite is modified by the second organic modifier, and the degradation effect of the in-situ repairing agent on halogenated organic pollutants can be improved.
Comparative example 2
Modified biotite-supported nano zero-valent iron and modified hectorite-supported nano zero-valent iron were prepared according to the method of example 1, which is different from example 1 in that:
FeCl in step (1)3Replacing ZnCl2Obtaining modified biotite loaded nano zero-valent iron;
FeCl in step (2)3Replacing ZnCl2Obtaining modified hectorite loaded nano zero-valent iron;
the application comprises the following steps: after 0.2g of the modified biotite loaded nano zero-valent zinc and the modified hectorite loaded nano zero-valent zinc prepared in example 1 and the modified biotite loaded nano zero-valent iron and the modified hectorite loaded nano zero-valent iron prepared in comparative example 1 are respectively placed in 20mL of decabromodiphenyl ether aqueous solution with the concentration of 0.05mol/L and degraded for 1.5h, the degradation rate of decabromodiphenyl ether is compared and found: the degradation rate of the decabromodiphenyl oxide by the modified biotite loaded nano zero-valent zinc is improved by 1.4 times compared with that by the modified biotite loaded nano zero-valent iron, and the degradation rate of the decabromodiphenyl oxide by the modified hectorite loaded nano zero-valent zinc is improved by 1.2 times compared with that by the modified hectorite loaded nano zero-valent iron. The invention has higher activity of loading the nano zero-valent zinc on the modified biotite or the modified hectorite than the activity of loading the nano zero-valent iron on degrading halogenated organic pollutants.
Example 4
(1) Preparation of biotite loaded nano zero-valent zinc
10g of biotite and 50mL of deionized water are stirred and mixed for 5min, and 0.02mol of ZnCl is added2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated biotite;
stirring and mixing 10g of zinc ion saturated biotite and 500mL of deionized water uniformly for 10min, adjusting the pH value to 3, and adding 0.25mol of Ce (BH) into the obtained slurry under the conditions of nitrogen atmosphere and room temperature4)3Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain the biotite loaded nano zero-valent zinc.
(2) Preparation of hectorite loaded nano zero-valent zinc
10g of hectorite and 50mL of deionized water are stirred and mixed for 5min, and 0.02mol of ZnCl is added2Stirring and mixing uniformly, adjusting the pH value of the obtained mixed solution to 3.5, carrying out ion exchange reaction for 18h at room temperature under the stirring condition, centrifuging to remove supernatant, and repeating the ion exchange reaction for 3 times to obtain zinc ion saturated hectorite;
stirring and mixing 10g of zinc ion saturated hectorite and 500mL of deionized water uniformly for 10min, adjusting the pH value to 3, and obtaining slurry under the conditions of nitrogen atmosphere and room temperatureAdding 0.25mol of NaBH into the solution4Stirring and mixing, carrying out reduction reaction for 5min, then carrying out solid-liquid separation, and sequentially washing the obtained solid component with deionized water, ethanol and drying to obtain the hectorite loaded nano zero-valent zinc.
Comparative example 3
(1) Preparation of Ce (BH)4)3Reduced nano zero-valent zinc
Under the conditions of protective atmosphere and stirring, Ce (BH)4)3Aqueous solution (2mol/L, 200mL) was added dropwise to ZnCl2After the completion of the dropwise addition, a third reduction reaction was carried out for 5min in an aqueous solution (200mL, 0.1mol/L, pH 3), followed by solid-liquid separation, and the obtained solid component was washed with deionized water to obtain Ce (BH)4)3Reduced nano zero-valent zinc.
(2) Preparation of NaBH4Reduced nano zero-valent zinc
Under the condition of protective atmosphere and stirring, NaBH is added4Aqueous solution (2mol/L, 200mL) was added dropwise to ZnCl2After the completion of the dropwise addition, the reaction mixture was subjected to a fourth reduction reaction for 5min in an aqueous solution (200mL, 0.1mol/L, pH 3), followed by solid-liquid separation, and the obtained solid component was washed with deionized water to obtain NaBH4Reduced nano zero-valent zinc.
The biotite prepared in example 4 supported nano zero valent zinc (5g, wherein nano zero valent zinc is 0.16g), the hectorite supported nano zero valent zinc (5g, wherein nano zero valent zinc is 0.16g), and Ce (BH) prepared in comparative example 34)3Reduced nano zero valent zinc (0.16g) and NaBH4Reduced nanometer zero-valent zinc (0.16g) is respectively added into 1L decabromodiphenyl ether aqueous solution with the concentration of 0.05mol/L, and after the degradation reaction lasts for 2 hours, the degradation rate of the decabromodiphenyl ether is compared to find that: biotite loaded nano zero-valent zinc ratio Ce (BH)4)3The degradation rate of the reduced nano zero-valent zinc to the decabromodiphenyl oxide is improved by 3.1 times, and the ratio of the nano zero-valent zinc loaded on the laponite to NaBH4The degradation rate of the reduced nano zero-valent zinc to the decabromodiphenyl oxide is improved by 4.5 times. It is shown that under the condition of the same quality of the nano zero-valent zinc, the loading of both biotite and hectorite can greatly improve the halogenated organic of the nano zero-valent zincDegradation activity of contaminants.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. An in-situ repairing medicament comprises modified biotite loaded nano zero-valent zinc, modified hectorite loaded nano zero-valent zinc, starch and edible oil;
the ratio of the total mass of the modified biotite loaded nanometer zero-valent zinc, the modified hectorite loaded nanometer zero-valent zinc and the starch to the volume of the edible oil is 400-600 g: 1L;
the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc is loaded on the middle layer of the modified biotite; the modified biotite is obtained by modifying biotite with a first organic modifier, wherein the first organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol;
the nanometer zero-valent zinc in the modified hectorite-loaded nanometer zero-valent zinc is loaded on the middle layer of the modified hectorite; the modified hectorite is obtained by modifying hectorite with a second organic modifier, wherein the second organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, 2-ethylhexyl acrylate and n-octanol.
2. The in-situ remediation agent of claim 1, wherein the mass ratio of the nano zero-valent zinc loaded on the modified biotite, the nano zero-valent zinc loaded on the modified hectorite and the starch is (5-7): (10-12): (1-5).
3. The in-situ remediation agent of claim 1 or 2, wherein the particle size of the nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc and the particle size of the nano zero-valent zinc in the modified hectorite-loaded nano zero-valent zinc are independently 0.5-2 nm.
4. The in-situ remediation agent of claim 3, wherein the loading of nano zero-valent zinc in the modified biotite-loaded nano zero-valent zinc and the loading of nano zero-valent zinc in the modified hectorite-loaded nano zero-valent zinc are independently 2 to 4 wt%.
5. The in-situ remediation agent of claim 1, 2 or 4, wherein the preparation method of the modified biotite loaded with nano zero-valent zinc comprises the following steps:
mixing biotite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated biotite;
mixing the zinc ion saturated biotite and a first organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated biotite; the first organic modifier comprises alkyl substituted ammonium bromide, azodiisobutyronitrile, methyl methacrylate and n-octanol;
saturating the modified zinc ion with biotite and Ce (BH) in protective atmosphere4)3Mixing, and carrying out reduction reaction to obtain the modified biotite loaded nano zero-valent zinc.
6. The in situ remediation agent of claim 5, wherein the ratio of the mass of alkyl-substituted ammonium bromide, the mass of azobisisobutyronitrile, the volume of methyl methacrylate, and the volume of n-octanol is (5 to 10) g: (0.5-1) g: 10mL of: (25-40) mL.
7. The in-situ remediation agent of claim 1, 2 or 4, wherein the preparation method of the modified hectorite loaded nano zero-valent zinc comprises the following steps:
mixing hectorite, soluble zinc salt and water, adjusting the pH value of the obtained mixed solution to 3-4, and carrying out ion exchange reaction to obtain zinc ion saturated hectorite;
mixing the zinc ion saturated hectorite and a second organic modifier in a protective atmosphere, and carrying out a crosslinking reaction to obtain modified zinc ion saturated hectorite; the second organic modifier comprises alkyl substituted ammonium bromide, azobisisobutyronitrile, 2-ethylhexyl acrylate and n-octanol;
in a protective atmosphere, the modified zinc ion saturated hectorite and NaBH4Mixing, and carrying out reduction reaction to obtain the modified hectorite loaded nano zero-valent zinc.
8. The in situ remediation agent of claim 7, wherein the ratio of the mass of alkyl-substituted ammonium bromide, the mass of azobisisobutyronitrile, the volume of 2-ethylhexyl acrylate, and the volume of n-octanol is (5-10) g: (0.5-1) g: 30mL of: (25-40) mL.
9. The method for preparing the in-situ repairing medicament of any one of claims 1 to 8, comprising the following steps:
mixing the modified biotite loaded nano zero-valent zinc, the modified hectorite loaded nano zero-valent zinc, starch and edible oil to obtain the in-situ repairing medicament.
10. The use of the in-situ remediation agent of any one of claims 1 to 8 or the in-situ remediation agent prepared by the preparation method of claim 9 for in-situ remediation of halogenated organic pollutants.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010389791.7A CN111534305B (en) | 2020-05-11 | 2020-05-11 | In-situ repair medicament and preparation method and application thereof |
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