CN111676020B - Composite soil remediation agent and preparation method and application thereof - Google Patents
Composite soil remediation agent and preparation method and application thereof Download PDFInfo
- Publication number
- CN111676020B CN111676020B CN202010638308.4A CN202010638308A CN111676020B CN 111676020 B CN111676020 B CN 111676020B CN 202010638308 A CN202010638308 A CN 202010638308A CN 111676020 B CN111676020 B CN 111676020B
- Authority
- CN
- China
- Prior art keywords
- montmorillonite
- magnesium
- dispersion liquid
- iron
- soil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
- C09K17/02—Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
- C09K17/08—Aluminium compounds, e.g. aluminium hydroxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
- B01J20/12—Naturally occurring clays or bleaching earth
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
-
- 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
-
- 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
- C09K17/02—Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
- C09K17/04—Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only applied in a physical form other than a solution or a grout, e.g. as granules or gases
-
- 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 discloses a composite soil repairing agent as well as a preparation method and application thereof, belonging to the technical field of heavy metal soil repair, wherein the composite soil repairing agent comprises the following components in parts by weight: magnesium/iron-montmorillonite and biochar. The magnesium/iron-montmorillonite can effectively adsorb and fix ionic heavy metals in soil, reduce the bioavailability of the heavy metals, and further reduce the toxic effect of the heavy metals on a biological chain. The repairing effects of zinc, copper, lead and cadmium can respectively reach 50.29-64.50%, 71.11-85.04%, 85.10-93.87% and 2.75-59.50%.
Description
Technical Field
The invention belongs to the technical field of heavy metal soil remediation, and particularly relates to a composite soil remediation agent and a preparation method and application thereof.
Background
The heavy metal pollution of soil is one of the most extensive and most harmful environmental problems in the current environmental pollution. Heavy metals in soil are of great concern due to their long-term, irreversible, covert, and other characteristics. At present, the polluted farmland in China is about 8.3 percent of the total farmland, about 10 ten thousand square kilometers of farmland is polluted, and about 90 percent of the polluted farmland is related to heavy metal pollution. According to the national soil pollution state survey bulletin published by the ministry of environmental protection and the ministry of national soil resources 2014: the number of the soil over-standard points accounts for 19.4% of the total number of the survey points, wherein the over-standard rates of the cadmium pollutant, the lead pollutant and the zinc pollutant are respectively 7.0%, 1.5% and 0.9%, and the over-standard rates are one of main heavy metal pollutants.
The repair technology of heavy metal contaminated soil is mainly divided into in-situ repair and ex-situ repair. The in-situ repair mode mainly comprises a physical technology, a chemical technology and a biological repair technology. The physical technology comprises a soil dressing and soil turning method, heat treatment separation, electrokinetic repair, isolation embedding and the like. Chemical techniques include chemical fixation, chemical leaching, chemical redox, and the like. Bioremediation techniques include phytoremediation, microbial remediation, animal remediation, and the like. The bioremediation method generally has the problems of low remediation efficiency, high treatment cost and the like. The traditional physical repair methods such as landfill, physical leaching, soil turning repair and the like have large engineering quantity and high cost, and often cause the damage of the soil structure and the loss of certain nutrient elements. Chemical fixation restores soil by adding a chemical restoring agent into soil, and is emphasized due to the characteristics of simple operation, low investment and the like, however, the conventional soil restoring agent such as lime, biochar, compost and the like has different problems, for example, biochar can reduce the biological effectiveness of heavy metal pollutants in soil through adsorption, and the restoring effect is realized. However, organic matters in the soil are easily mineralized, and the change of the pH value of the soil can also cause desorption, so that heavy metal pollutants can be released again, the repairing effect of the biochar is unstable, rebounding occurs, and in addition, the problems that the reduction efficiency of the existing other repairing agents is not obvious enough, the physicochemical property of the soil is adversely affected and the like exist.
Disclosure of Invention
The invention provides a soil remediation agent and a preparation method and application thereof, aiming at solving the problems of unstable remediation effect, poor remediation effect and the like of the existing single activated carbon/charcoal.
In order to solve the technical problems, the invention adopts the following technical scheme:
a composite soil remediation agent, comprising: magnesium/iron-montmorillonite and biochar.
The magnesium/iron compound is loaded on the surface and in the pores of the montmorillonite.
Preferably, the magnesium/iron-montmorillonite microstructure is: montmorillonite in the form of flakes and magnesium/iron compound in the form of spheres.
The magnesium/iron compound described herein is a mixture of iron oxide, magnesium silicate.
The mass ratio of the magnesium/iron-montmorillonite to the biochar is 1:9-10: 0;
preferably, the biochar is wheat-based biochar;
preferably, the mass ratio of the magnesium/iron-montmorillonite material to biochar is selected from: 1:9, 3:7, 4:6, or, 10: 0.
A preparation method of a composite soil remediation agent is characterized by comprising the following steps:
s1, dispersing montmorillonite, magnesium chloride and ferrous oxalate in water respectively to obtain montmorillonite dispersion liquid, magnesium chloride dispersion liquid and ferrous oxalate dispersion liquid;
s2, adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid for reaction to obtain a first-step dispersion liquid; adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid to react to obtain a second-step dispersion liquid;
s3, washing, drying and calcining the dispersion liquid in the second step after the hydro-thermal treatment is finished to obtain magnesium/iron-montmorillonite;
s4, mixing the magnesium/iron-montmorillonite material with biochar to obtain the soil remediation agent.
The magnesium/iron-montmorillonite material and the biochar are mixed according to the mass ratio of 1:9-10: 0;
preferably, the mass-to-volume ratio of montmorillonite to water in the montmorillonite dispersion is 10 g: 300mL-40 g: 300mL, preferably 25 g: 300 mL;
preferably, the magnesium chloride concentration in the magnesium chloride dispersion is 0-1mol/L, preferably 0.33 mol/L;
preferably, the concentration of the ferrous oxalate in the ferrous oxalate dispersion liquid is 0-1mol/L, preferably 0.33 mol/L;
preferably, the mass ratio of the magnesium/iron-montmorillonite material to biochar is selected from: 1:9, 3:7, 4:6, 10: 0.
The reaction time of adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid is 5-20 minutes, preferably 10 minutes;
preferably, the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid are added into the first-step dispersion liquid for reaction for 20-60 minutes, preferably 30 minutes;
preferably, the hydrothermal pretreatment is autoclave hydrothermal pretreatment; the reaction time of the autoclave hydrothermal treatment is 2-6h, preferably 5 h; the reaction temperature is 150-200 ℃, preferably 180 ℃;
preferably, the washing is deionized water and ethanol washing; the drying temperature is 50-80 ℃, and preferably 60 ℃;
more preferably, the reaction time of the calcination treatment is 2 to 5 hours, preferably 3 hours; the reaction temperature is 450 ℃ and 750 ℃, preferably 500 ℃.
The composite soil remediation agent and/or the application of the composite soil remediation agent prepared by the preparation method in the aspect of heavy metal soil remediation.
And mixing the composite soil remediation agent with the heavy metal contaminated soil to finish remediation of the heavy metal contaminated soil.
The addition amount of the heavy metal contaminated soil remediation agent is 1-5wt%, preferably 3wt% of the total mass of the heavy metal contaminated soil to be remedied.
The repairing time is 90-120 days, preferably 110 days;
preferably, the water content of the soil is maintained between 50% and 80% of the maximum water holding capacity during remediation;
preferably, the heavy metal is selected from cadmium, zinc, copper, and/or, lead.
A method for repairing composite heavy metal contaminated soil by adopting a composite soil repairing agent comprises the following steps:
fully mixing the composite soil remediation agent with the composite heavy metal contaminated soil to enable the composite soil remediation agent to react with heavy metals in the soil, so that the heavy metals form a stable chemical form to finish remediation of the heavy metal soil;
the composite soil remediation agent comprises magnesium/iron-montmorillonite and biochar in a mass ratio of 1:9, 3:7, 4:6 or 10: 0; the addition amount accounts for 1-5wt%, preferably 3wt% of the total soil mass of the soil to be repaired.
The method for repairing the soil polluted by the compound heavy metals by using the compound soil repairing agent is characterized in that the repairing time is 90-120 days, preferably 110 days; maintaining the water content of the soil at 50% -80% of the maximum water holding capacity during the restoration period; the heavy metals include cadmium, zinc, copper and lead.
The biochar is wheat-based biochar and is purchased from Wuhan Guanggu Gu blue flame new energy GmbH.
The preparation method of the compound soil remediation agent comprises the following steps:
s1, dispersing montmorillonite into water by ultrasonic wave to obtain dispersion liquid of montmorillonite;
ultrasonically dispersing magnesium chloride into water to obtain a dispersion liquid of the magnesium chloride;
dispersing ferrous oxalate into water under the conditions of ultrasound and/or stirring to obtain a dispersion liquid of the ferrous oxalate;
s2, adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid under the stirring condition, and reacting to obtain a first-step dispersion liquid; dropwise adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid under the stirring condition, reacting, and obtaining a second-step dispersion liquid after the reaction is finished;
s3, placing the dispersion liquid obtained in the second step into a high-pressure kettle for hydro-thermal treatment, washing with deionized water and ethanol after the hydro-thermal treatment is finished, and drying at 50-80 ℃, preferably 60 ℃ to obtain a primary magnesium/iron-montmorillonite material;
calcining the preliminary magnesium/iron-montmorillonite material in a muffle furnace to obtain a magnesium/iron-montmorillonite material;
and mixing the magnesium/iron-montmorillonite material and biochar according to a mass ratio of 1:9-10:0 to obtain the soil remediation agent.
The mass volume ratio of montmorillonite to water in the montmorillonite dispersion liquid is 10 g: 300mL-40 g: 300mL, preferably 25 g: 300 mL; the concentration of magnesium chloride in the magnesium chloride dispersion liquid is 0-1mol/L, preferably 0.33 mol/L; the concentration of the ferrous oxalate in the ferrous oxalate dispersion liquid is 0-1mol/L, preferably 0.33 mol/L; the mass ratio of the magnesium/iron-montmorillonite material to the biochar is selected from the following group: 1:9, 3:7, 4:6, 10: 0.
The reaction time of adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid is 5-20 minutes, preferably 10 minutes; the time for dropwise adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid to react is 20-60 minutes, and preferably 30 minutes.
The reaction time of the autoclave hydrothermal treatment is 2-6h, preferably 5h, the reaction temperature is 150-; the reaction time of the muffle furnace calcination treatment is 2-5h, preferably 3 h; the reaction temperature is 450 ℃ and 750 ℃, preferably 500 ℃.
Compared with the prior art, the invention has the advantages that:
1. the invention utilizes magnesium/iron-montmorillonite to repair heavy metal soil, the microstructure of the magnesium/iron-montmorillonite comprises flaky montmorillonite and spherical magnesium/iron compound, and the magnesium/iron compound is loaded on the surface and in the pores of the montmorillonite. The presence of montmorillonite effectively prevents agglomeration of the magnesium/iron compound particles, and the presence of the magnesium/iron compound increases the adsorption properties of montmorillonite. The method has the advantages of simplicity, high efficiency, environmental friendliness and the like, and has a good remediation effect on the soil polluted by the compound heavy metal. In addition, hydroxyl groups, carboxyl functional groups, magnesium ions and the like on the surface of the material can react with heavy metals such as cadmium, zinc, copper, lead and the like in soil through ion exchange, so that the heavy metals are formed into stable chemical forms and fixed on the surface of the material. Prevent the environmental migration and diffusion of the heavy metal and reduce the toxic degree of the heavy metal in the environment. Therefore, the magnesium/iron-montmorillonite can effectively adsorb and fix the ionic heavy metal in the soil, reduce the bioavailability of the heavy metal and further reduce the toxic action of the heavy metal on a biological chain.
Regarding "the presence of a magnesium/iron compound increases the adsorption properties of montmorillonite", the principle is that, first, the presence of a magnesium/iron compound increases the PH, the PH of the magnesium/iron compound is higher than that of montmorillonite, and, second, the electrostatic adsorption force of the magnesium/iron compound to heavy metals is greater than that of montmorillonite to heavy metals.
2. Besides strong heavy metal adsorption regulation capacity, the magnesium/iron-montmorillonite can also play a role in improving the physicochemical properties of soil after being applied to the soil, such as increasing the pH value of the soil, increasing the water-soluble carbon content of the soil and the like. This is because: the magnesium/iron-montmorillonite is alkaline, so that the acid value of part of soil can be neutralized after entering the soil, and meanwhile, Fe, Mg oxide and the like form insoluble complexes with heavy metals, so that the precipitation of the metals is effectively improved, and the pH value of the soil is increased. The material contains partial water-soluble carbon, and the partial water-soluble carbon is dissolved out after the material is applied into soil, so that the content of the water-soluble carbon is increased.
3. The components in the composite repairing agent are magnesium/iron-montmorillonite and biochar, wherein the biochar has wide sources and low synthesis and transportation cost, and the cost is greatly reduced; and secondly, as the biochar is rich in organic carbon, the biochar is added into the soil, so that the content of humus and organic matters in the soil can be improved to a certain degree, and the nutritional status of the soil can be indirectly improved by absorbing other nutrients. In addition, the magnesium/iron-montmorillonite and the biochar are all non-toxic, green and environment-friendly materials.
The principle of action of the present invention for remediating contaminants is different from the prior art. First, due to the difference in repair materials: in the invention, most of the materials are combined by magnesium/iron-montmorillonite and biochar, and the magnesium/iron-montmorillonite and biochar can interact with each other in the process of fixing heavy metals. Secondly, differences in the nature of the contaminant carrier, contaminant, and contaminant can mean differences in the principle of action of contaminant removal. For example: firstly, after the material is applied, the physicochemical properties of the soil (including the states of nutrients required by biological growth such as pH, WSOC, TOC, carbon and nitrogen) are improved, and certain physicochemical property improvements can be directly acted on the heavy metal to facilitate the fixation of the heavy metal; the improvement of certain physicochemical properties can indirectly act on the soil remediation of heavy metals by providing better living environment for microorganisms with the capability of biologically adsorbing or fixing the heavy metals; the "original composition and state" of the water and soil are different, and the influence of the material is different. Second, chromium may exist primarily at +3 and +6 valences, with the +6 valency toxicity being greater than +3 valency; the zinc, copper, lead and cadmium exist mainly in a valence of + 2; the two removal mechanisms are originally different. Third, competitive adsorption can exist in the co-remediation process of the composite pollutants, the removal of another heavy metal can be influenced by the existence of one heavy metal, and the competitive adsorption cannot exist or can be ignored in the removal process of single heavy metal pollution.
Drawings
FIG. 1 is a scanning electron micrograph of Mg/Fe-montmorillonite used in the examples of the present invention.
FIG. 2 is a Fourier infrared spectrum of magnesium/iron-montmorillonite used in the examples of the present invention.
FIG. 3 is an X-ray diffraction pattern of magnesium/iron-montmorillonite used in examples of the present invention.
FIG. 4 is a comparison graph of the content of heavy metals extracted from soil after remediation of heavy metal contaminated soil with magnesium/iron-montmorillonite in different addition amounts.
FIG. 5 is a graph showing the comparison of the pH value of soil after the soil contaminated by the composite heavy metal is repaired by magnesium/iron-montmorillonite with different addition amounts.
The labels in the figure are listed below: CK: blank control; M1H 9: the mass ratio of the magnesium/iron-montmorillonite to the biochar is 1: 9; M3H 7: the mass ratio of the magnesium/iron-montmorillonite to the biochar is 3: 7; M4H 6: the mass ratio of the magnesium/iron-montmorillonite to the biochar is 4: 6; M10H 0: the mass ratio of the magnesium/iron-montmorillonite to the biochar is 10: 0.
Detailed Description
The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.
The magnesium/iron-montmorillonite used in the following examples was prepared by the following method:
(a) adding 2.5g of montmorillonite into 30ml of water to obtain montmorillonite suspension; adding 0.01g of cetyltrimethylammonium bromide and 5ml of ammonia water (25 wt%) to the montmorillonite suspension, and stirring at 25 ℃ for 10min to obtain a mixed solution;
(b) dissolving 2.013g of magnesium chloride in 30ml of water to obtain a magnesium chloride solution; adding 1.781g of ferrous oxalate into 30ml of water to obtain a ferrous oxalate suspension; under the condition of stirring, dropwise adding a magnesium chloride solution and a ferrous oxalate suspension into the mixed solution obtained in the step (a) in sequence to prepare a new mixed solution;
(c) transferring the mixed solution obtained in the step (b) into a hydrothermal reaction kettle for hydrothermal synthesis reaction at 180 ℃ for 5 hours, washing the mixed solution for three times by using deionized water and ethanol after the reaction is finished, and drying the washed mixed solution at 60 ℃ to obtain dark green powder; and transferring the obtained dark green powder into a muffle furnace for calcination at 500 ℃ for 3h to obtain the magnesium/iron-montmorillonite material.
FIG. 1 is a scanning electron micrograph of Mg/Fe-montmorillonite used in the examples of the present invention. As can be seen from the figure, spherical or globular magnesium/iron compound nanoparticles are well immobilized on the surface of montmorillonite. In addition, the magnesium/iron compound nanoparticles are densely and uniformly coated on the surface of the montmorillonite, which shows that the montmorillonite effectively prevents the aggregation of the magnesium/iron compound nanoparticles.
FIG. 2 is a Fourier infrared spectrum of magnesium/iron-montmorillonite used in the examples of the present invention. 3627cm as can be seen-1And 3423cm-1The absorption band of (a) is from the structural water and interlayer water of montmorillonite; the magnesium/iron-montmorillonite material is 3697cm-1The ribbon at (a) is attributed to stretching and bending vibration of-OH; the polymerization was confirmed in magnesium/iron-montmorillonite, 1032cm-1Disappearance of Si-O stretching vibration, 1043cm-1A new band appears. At 600-540 and 450-400cm-1The additional absorption bands in the range correspond to tensile vibrations of the metal oxygen bonds at tetrahedral and octahedral sites, respectively.
FIG. 3 is an X-ray diffraction pattern of magnesium/iron-montmorillonite used in examples of the present invention. As can be seen, the magnesium/iron-montmorillonite composition is more complex than montmorillonite, and it is composed of minerals such as montmorillonite, iron oxide, magnesium silicate, and other iron and magnesium compounds. Among them, the diffraction peak at 29.77 ° is a characteristic diffraction peak for the magnesium silicate (JCPDS card No.99-0045) (221) crystal plane, and the diffraction peak at 35.41 ° 2 θ is a characteristic diffraction peak for the iron oxide (JCPDS card No.99-0060) (311) crystal plane.
Group 1 example, soil remediation Agents of the invention
The present group of embodiments provides a soil remediation agent, comprising: magnesium/iron-montmorillonite.
The magnesium/iron compound is loaded on the surface and in the pores of the montmorillonite.
Preferably, the magnesium/iron-montmorillonite microstructure is: montmorillonite in the form of flakes and magnesium/iron compound in the form of spheres.
Also comprises biochar; the mass ratio of the magnesium/iron-montmorillonite to the biochar is 1:9-10: 0;
preferably, the biochar is wheat-based biochar;
preferably, the mass ratio of the magnesium/iron-montmorillonite material to biochar is selected from: 1:9, 3:7, 4:6, or, 10: 0.
Group 2 example, method for preparing soil remediation agent of the present invention
The embodiment of the group provides a preparation method of a soil remediation agent, which is characterized by comprising the following steps:
s1, dispersing montmorillonite, magnesium chloride and ferrous oxalate in water respectively to obtain montmorillonite dispersion liquid, magnesium chloride dispersion liquid and ferrous oxalate dispersion liquid;
s2, adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid for reaction to obtain a first-step dispersion liquid; adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid to react to obtain a second-step dispersion liquid;
and S3, washing, drying and calcining the second-step dispersion liquid after the hydrothermal treatment is finished to obtain the magnesium/iron-montmorillonite.
Further comprising: s4, mixing the magnesium/iron-montmorillonite material and biochar according to a mass ratio of 1:9-10:0 to obtain the soil remediation agent;
preferably, the mass-to-volume ratio of montmorillonite to water in the montmorillonite dispersion is 10 g: 300mL-40 g: 300mL, preferably 25 g: 300 mL;
preferably, the magnesium chloride concentration in the magnesium chloride dispersion is 0-1mol/L, preferably 0.33 mol/L;
preferably, the concentration of the ferrous oxalate in the ferrous oxalate dispersion liquid is 0-1mol/L, preferably 0.33 mol/L;
preferably, the mass ratio of the magnesium/iron-montmorillonite material to biochar is selected from: 1:9, 3:7, 4:6, 10: 0.
The reaction time of adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid is 5-20 minutes, preferably 10 minutes;
preferably, the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid are added into the first-step dispersion liquid for reaction for 20-60 minutes, preferably 30 minutes;
preferably, the hydrothermal pretreatment is autoclave hydrothermal pretreatment; the reaction time of the autoclave hydrothermal treatment is 2-6h, preferably 5 h; the reaction temperature is 150-200 ℃, preferably 180 ℃;
preferably, the washing is deionized water and ethanol washing; the drying temperature is 50-80 ℃, and preferably 60 ℃;
more preferably, the reaction time of the calcination treatment is 2 to 5 hours, preferably 3 hours; the reaction temperature is 450 ℃ and 750 ℃, preferably 500 ℃.
The embodiment of the group provides the soil remediation agent of any one of the embodiment in the group 1, and/or the application of the composite soil remediation agent prepared by the preparation method of any one of the embodiment in the aspect of heavy metal soil remediation.
In a specific embodiment, the composite soil remediation agent is mixed with heavy metal contaminated soil to complete remediation of the heavy metal contaminated soil.
In some embodiments, the heavy metal contaminated soil remediation agent is added in an amount of 1-5wt%, preferably 3wt% of the total mass of the heavy metal contaminated soil to be remediated.
In other embodiments, the repair time is 90-120 days, preferably 110 days;
preferably, the water content of the soil is maintained between 50% and 80% of the maximum water holding capacity during remediation;
preferably, the heavy metal is selected from cadmium, zinc, copper, and/or, lead.
Experimental example 1:
the invention relates to a method for repairing composite heavy metal contaminated soil by using a magnesium/iron-montmorillonite and biochar composite material, which comprises the following steps:
(1) preparing the composite heavy metal contaminated soil: the test soil is collected from farmland in the Yuenu area of Changsha in Hunan, the composite heavy metal contaminated soil is prepared by a method of artificially adding zinc, copper, lead and cadmium solutions, and the composite heavy metal contaminated soil is cultured at a constant temperature of 25 ℃ for two months, so that the heavy metal form tends to be stable. The total zinc, copper, lead and cadmium contents in the soil measured by the graphite furnace digestion method are respectively 840mg/kg of 650-. Soil remediation experiments were subsequently performed.
(2) Repairing the composite heavy metal contaminated soil: preparing five groups of composite heavy metal contaminated soil with the same weight (CK) after the stabilization in the step (1), wherein the first group is not added with any repairing agent and is used as a blank control group; a second group is added with a compound soil remediation agent (magnesium/iron-montmorillonite: biochar ═ 0:10) (M0H10) which accounts for 3 percent of the weight of the compound heavy metal contaminated soil; adding composite soil repairing agent (magnesium/iron-montmorillonite: biochar ═ 1:9) (M1H9) 3% of the weight of the composite heavy metal contaminated soil into the third group, and uniformly mixing; adding composite soil repairing agent (magnesium/iron-montmorillonite: biochar ═ 3:7) (M3H7) 3wt% of the composite heavy metal contaminated soil into the fourth group, and mixing uniformly; adding a compound soil remediation agent (magnesium/iron-montmorillonite: biochar 4:6) (M4H6) in an amount of 3wt% of the compound heavy metal contaminated soil, and mixing uniformly; and adding a composite soil remediation agent (magnesium/iron-montmorillonite: biochar ═ 10:0) (M10H0) in an amount which is 3% of the weight of the composite heavy metal contaminated soil, and uniformly mixing. And (3) respectively supplementing water to the four groups of compound heavy metal contaminated soil by using tap water, so that the water content of the compound heavy metal contaminated soil is kept at about 60% of the maximum field water capacity. After 110 days of stabilization, acetic acid solution (pH 2.88) is used as an extracting agent to respectively extract heavy metals in four groups of soil polluted by the compound heavy metals, and the TCLP leaching method can better reflect the bioavailability of the heavy metals in the soil. And measuring the content of the composite heavy metals (zinc, copper, lead and cadmium) by using an inductively coupled plasma emission spectrometer (ICP-OES). The results are shown in FIG. 4, and the soil restoration effect is shown by the immobilization rate of heavy metals. The immobilization rate (heavy metal content of blank group-treated group)/heavy metal content of blank group, and the results are shown in table 1.
Table 1 comparison table of the fixing effect of the composite repairing agent with different addition ratios on heavy metals in soil after repairing
| Treatment method | CK | M0H10 | M1H9 | M3H7 | M4H6 | M10H0 |
| Fixation ratio (%) of Zinc | 50.29 | 53.04 | 52.89 | 53.85 | 55.03 | 64.50 |
| Fixation ratio (%) of copper | 71.11 | 78.86 | 78.88 | 76.85 | 76.27 | 98.04 |
| Fixation ratio of lead (%) | 85.10 | 90.67 | 93.21 | 92.37 | 93.23 | 93.87 |
| Fixation ratio (%) of cadmium | 2.75 | 21.00 | 9.25 | 14.75 | 26.50 | 59.50 |
As can be seen from FIG. 4, after 110 days of repair, the repair effects of zinc, copper, lead and cadmium respectively reach 50.29-64.50%, 71.11-85.04%, 85.10-93.87% and 2.75-59.50%. The fixation of zinc, copper and lead in the blank group may be mainly the cause of aging. The effect of the test group added with the repairing agent is obviously better than that of the blank control group. In addition, no matter the ratio of the magnesium/iron-montmorillonite to the biochar of the repairing agent, the content of heavy metals (zinc, copper, lead and cadmium) in the soil TCLP extracting solution in the test group added with the repairing agent is obviously reduced. The lowest immobilization rates of zinc, copper, lead and cadmium are 52.89%, 76.27%, 90.67% and 9.25% respectively, which shows that the combination of magnesium/iron-montmorillonite and biochar can effectively reduce the bioavailability of heavy metals in the composite contaminated soil, reduce the toxic action of heavy metals on animals and plants and improve the soil quality. Therefore, the composite material can be applied to the remediation and treatment of the soil polluted by the composite heavy metals (zinc, copper, lead and cadmium). In addition, it is worth noting that in order to repair the immobilization rate of four metals simultaneously, there may be adsorption competition and the like which affect the ion immobilization, and the immobilization performance of the repairing agent applied to the soil polluted by a single heavy metal is worth discussing.
Experimental example 2:
the research on the soil restoration physical and chemical properties of the composite material restoration agent comprises the following steps:
preparing five groups of the stabilized composite heavy metal contaminated soil of the example (1) with the same weight, wherein the first group is used as a blank control group (CK) without adding any repairing agent; a second group is added with a compound soil remediation agent (magnesium/iron-montmorillonite: biochar ═ 0:10) (M0H10) which accounts for 3 percent of the weight of the compound heavy metal contaminated soil; adding composite soil repairing agent (magnesium/iron-montmorillonite: biochar ═ 1:9) (M1H9) 3% of the weight of the composite heavy metal contaminated soil into the third group, and uniformly mixing; adding composite soil repairing agent (magnesium/iron-montmorillonite: biochar ═ 3:7) (M3H7) 3wt% of the composite heavy metal contaminated soil into the fourth group, and mixing uniformly; adding a compound soil remediation agent (magnesium/iron-montmorillonite: biochar 4:6) (M4H6) in an amount of 3wt% of the compound heavy metal contaminated soil, and mixing uniformly; and adding a composite soil remediation agent (magnesium/iron-montmorillonite: biochar ═ 10:0) (M10H0) in an amount which is 3% of the weight of the composite heavy metal contaminated soil, and uniformly mixing. And (3) respectively supplementing water to the four groups of compound heavy metal contaminated soil by using tap water, so that the water content of the compound heavy metal contaminated soil is kept at about 60% of the maximum field water capacity. After 110 days of stabilization, the water-soluble organic carbon content was extracted with water as a solvent and measured with a TOC instrument, and the results are shown in Table 2. The organic matter of the soil was measured by a combustion quantitative method, and the results are shown in table 2. The pH of the soil was measured by a pH meter, and the results are shown in fig. 5. And the condition of rice growth when the repairing agent is used for repairing heavy metal pollution is preliminarily examined (data not shown).
Table 2 water-soluble carbon content and organic matter content in composite heavy metal contaminated soil after adding composite material additive
As can be seen from FIG. 5, the pH value of the soil is changed after the composite repairing agent is added, the pH value of the acid soil is increased along with the increase of the addition amount of the magnesium/iron-montmorillonite, and the pH value of the pure biochar test group is also obviously higher than that of the blank control group. This is because both the magnesium/iron-montmorillonite and biochar are alkaline materials, which increase the pH of the soil, and the magnesium/iron-montmorillonite contains more alkalinity than the biochar used in the test, and therefore the pH of the soil is more affected by the magnesium/iron-montmorillonite. The increase of the pH value of the soil is beneficial to the fixation of heavy metal in the soil, and the content of heavy metal ions in a partially exchangeable state can be reduced. As can be seen from table 2, the addition of the material not only increases the pH of the soil, but also increases the content of water-soluble carbon and organic carbon in the soil, the content of water-soluble carbon is affected by the change of pH and the addition of biochar, and the content of organic carbon is significantly related to the addition of biochar, because biochar itself is rich in organic carbon material, and after the biochar is added into the soil, the organic carbon can be slowly released into the soil, so that the content of organic carbon in the soil can be increased, and the nutritional status of the soil can also be improved. The composite material additive composed of the magnesium/iron-montmorillonite and the biochar has certain improvement on the physicochemical property of soil, can improve the soil quality, and is beneficial to pollution treatment and subsequent reutilization.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. All technical schemes belonging to the idea of the invention belong to the protection scope of the invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention, and such modifications and embellishments should also be considered as within the scope of the invention.
Claims (26)
1. A composite soil remediation agent, comprising: magnesium/iron-montmorillonite and biochar;
the magnesium/iron-montmorillonite microstructure is as follows: flaky montmorillonite and spherical magnesium/iron compound;
the magnesium/iron compound is a mixture of ferric oxide and magnesium silicate;
the mass ratio of the magnesium/iron-montmorillonite to the biochar is 1:9-4: 6;
the preparation method of the composite soil remediation agent comprises the following steps:
s1, dispersing montmorillonite, magnesium chloride and ferrous oxalate in water respectively to obtain montmorillonite dispersion liquid, magnesium chloride dispersion liquid and ferrous oxalate dispersion liquid;
s2, adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid for reaction to obtain a first-step dispersion liquid; adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid to react to obtain a second-step dispersion liquid;
s3, washing, drying and calcining the dispersion liquid in the second step after the hydro-thermal treatment is finished to obtain magnesium/iron-montmorillonite;
s4, mixing the magnesium/iron-montmorillonite material with biochar to obtain the composite soil remediation agent;
the hydrothermal treatment is high-pressure kettle hydrothermal treatment; the reaction time of the high-pressure autoclave hydrothermal treatment is 2-6h, and the reaction temperature is 150-200 ℃;
the reaction time of the calcination is 2-5h, and the reaction temperature is 450-750 ℃.
2. The composite soil remediation agent of claim 1 wherein said magnesium/iron compound is loaded onto the surface and into the pores of montmorillonite.
3. The compound soil remediation agent of claim 1, wherein,
the biochar is wheat-based biochar.
4. The composite soil remediation agent of claim 1, wherein the mass ratio of magnesium/iron-montmorillonite material to biochar is selected from the group consisting of: 1:9, 3:7 or 4: 6.
5. The method of preparing a composite soil remediation agent of any one of claims 1 to 4 including the steps of:
s1, dispersing montmorillonite, magnesium chloride and ferrous oxalate in water respectively to obtain montmorillonite dispersion liquid, magnesium chloride dispersion liquid and ferrous oxalate dispersion liquid;
s2, adding cetyl trimethyl ammonium bromide and ammonia water into the montmorillonite dispersion liquid for reaction to obtain a first-step dispersion liquid; adding the magnesium chloride dispersion liquid and the ferrous oxalate dispersion liquid into the first-step dispersion liquid to react to obtain a second-step dispersion liquid;
s3, washing, drying and calcining the dispersion liquid in the second step after the hydro-thermal treatment is finished to obtain magnesium/iron-montmorillonite;
s4, mixing the magnesium/iron-montmorillonite material with biochar to obtain the composite soil remediation agent;
the hydrothermal treatment is high-pressure kettle hydrothermal treatment; the reaction time of the high-pressure autoclave hydrothermal treatment is 2-6h, and the reaction temperature is 150-200 ℃;
the reaction time of the calcination is 2-5h, and the reaction temperature is 450-750 ℃.
6. The method of claim 5, wherein said compound soil remediation agent is further prepared,
the mass volume ratio of montmorillonite to water in the montmorillonite dispersion liquid is 10 g: 300mL-40 g: 300 mL.
7. The method of claim 6 wherein the mass to volume ratio of montmorillonite to water in the montmorillonite dispersion is 25 g: 300 mL.
8. The method of claim 5 wherein said magnesium chloride dispersion has a magnesium chloride concentration of 0-1 mol/L.
9. The method of claim 8 wherein said magnesium chloride dispersion has a magnesium chloride concentration of 0.33 mol/L.
10. The method of claim 5 wherein said ferrous oxalate dispersion has a ferrous oxalate concentration of 0-1 mol/L.
11. The method of claim 10 wherein said ferrous oxalate dispersion has a ferrous oxalate concentration of 0.33 mol/L.
12. The method of claim 5 wherein said reaction is carried out by adding cetyl trimethyl ammonium bromide and ammonia water into said montmorillonite dispersion for 5-20 min.
13. The method of claim 12 wherein said adding cetyltrimethylammonium bromide and ammonia water into said montmorillonite dispersion for reaction time of 10 minutes.
14. The method of claim 5 wherein said magnesium chloride dispersion and ferrous oxalate dispersion are added to said first step dispersion for 20-60 minutes.
15. The method of claim 14 wherein said magnesium chloride dispersion and ferrous oxalate dispersion are added to said first step dispersion for 30 minutes.
16. The method of claim 5 wherein said autoclave hydrothermal treatment is carried out for 5 hours at a temperature of 180 ℃.
17. The method of claim 5 wherein said washing is deionized water and ethanol; the drying temperature was 60 ℃.
18. The method of claim 5 wherein said calcining is carried out for a reaction time of 3 hours at a reaction temperature of 500 ℃.
19. The use of the compound soil remediation agent of any one of claims 1 to 4, or the compound soil remediation agent prepared by the preparation method of any one of claims 5 to 18 for remediation of heavy metal soils.
20. The use of claim 19, wherein the remediation of heavy metal contaminated soil is accomplished by mixing the composite soil remediation agent with heavy metal contaminated soil.
21. The use of claim 20, wherein said composite soil remediation agent is added in an amount of 1 to 5wt% of the total mass of heavy metal contaminated soil to be remediated.
22. The use of claim 21, wherein said composite soil remediation agent is added in an amount of 3wt% of the total mass of heavy metal contaminated soil to be remediated.
23. Use according to claim 19, wherein the repair time is 90-120 days.
24. The use of claim 23, wherein the repair time is 110 days.
25. Use according to claim 19, wherein the soil moisture content is maintained during remediation between 50% and 80% of the maximum water capacity.
26. Use according to claim 19, wherein the heavy metal is selected from cadmium, zinc, copper, and/or lead.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010638308.4A CN111676020B (en) | 2020-07-03 | 2020-07-03 | Composite soil remediation agent and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010638308.4A CN111676020B (en) | 2020-07-03 | 2020-07-03 | Composite soil remediation agent and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111676020A CN111676020A (en) | 2020-09-18 |
| CN111676020B true CN111676020B (en) | 2021-05-25 |
Family
ID=72457296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010638308.4A Active CN111676020B (en) | 2020-07-03 | 2020-07-03 | Composite soil remediation agent and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111676020B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112934947B (en) * | 2021-03-31 | 2022-06-14 | 郑州大学 | Ecological restoration method for mining wasteland |
| CN114316993A (en) * | 2022-01-13 | 2022-04-12 | 刘金梅 | Soil pollution repairing agent and repairing method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106190158A (en) * | 2016-07-26 | 2016-12-07 | 湖北都兴隆农业技术有限公司 | A kind of soil-repairing agent for administering heavy metal pollution and production method thereof |
| WO2016191802A1 (en) * | 2015-05-29 | 2016-12-08 | Adelaide Research & Innovation Pty Ltd | Composite graphene-based material |
| CN107469765A (en) * | 2017-08-25 | 2017-12-15 | 北京工业大学 | A kind of preparation method of diatomite/ferrous acid magnesium base composite material |
| CN109174065A (en) * | 2018-10-22 | 2019-01-11 | 管敏富 | The preparation and the application in processing waste water from dyestuff that iron magnesium compound coats bentonite composite granule adsorbent |
| CN110003913A (en) * | 2019-05-06 | 2019-07-12 | 湖南大学 | It is a kind of based on magnesia-montmorillonite composite material mixed biologic charcoal heavy metal soil-repairing agent and restorative procedure |
| CN111234827A (en) * | 2020-01-17 | 2020-06-05 | 湖南大学 | Heavy metal contaminated soil remediation agent and preparation method and application thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6386796B1 (en) * | 2000-03-06 | 2002-05-14 | John H. Hull | Composite particles and methods for their application and implementation |
| CN107486141B (en) * | 2017-08-25 | 2020-08-18 | 北京工业大学 | Preparation method of magnesium oxide chemically modified diatomite with high adsorption capacity |
| CN107754757B (en) * | 2017-10-16 | 2020-08-18 | 北京工业大学 | Nano Fe3O4Composite material for modifying diatomite and preparation method thereof |
| CN108358290B (en) * | 2018-03-15 | 2021-05-04 | 湖南隆洲驰宇科技有限公司 | Preparation method of iron-based arsenic passivation material, iron-based arsenic passivation material prepared by method and application of iron-based arsenic passivation material |
-
2020
- 2020-07-03 CN CN202010638308.4A patent/CN111676020B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016191802A1 (en) * | 2015-05-29 | 2016-12-08 | Adelaide Research & Innovation Pty Ltd | Composite graphene-based material |
| CN106190158A (en) * | 2016-07-26 | 2016-12-07 | 湖北都兴隆农业技术有限公司 | A kind of soil-repairing agent for administering heavy metal pollution and production method thereof |
| CN107469765A (en) * | 2017-08-25 | 2017-12-15 | 北京工业大学 | A kind of preparation method of diatomite/ferrous acid magnesium base composite material |
| CN109174065A (en) * | 2018-10-22 | 2019-01-11 | 管敏富 | The preparation and the application in processing waste water from dyestuff that iron magnesium compound coats bentonite composite granule adsorbent |
| CN110003913A (en) * | 2019-05-06 | 2019-07-12 | 湖南大学 | It is a kind of based on magnesia-montmorillonite composite material mixed biologic charcoal heavy metal soil-repairing agent and restorative procedure |
| CN111234827A (en) * | 2020-01-17 | 2020-06-05 | 湖南大学 | Heavy metal contaminated soil remediation agent and preparation method and application thereof |
Non-Patent Citations (2)
| Title |
|---|
| "Efficient removal of hazardous lead, cadmium, and arsenic from aqueous environment by iron oxide modified clay-activated carbon composite beads";Radheshyam R. Pawar et al;《Applied Clay Science》;20180612;第162卷;第339-350页 * |
| "硅藻土基硅酸镁及铁酸镁原位生长制备及其吸附性能研究";王学凯;《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》;20190515(第5期);B014-504 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111676020A (en) | 2020-09-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109504398B (en) | Humic acid nano zero-valent iron soil Cr pollution remediation agent and preparation method thereof | |
| Ji et al. | Mixed bacteria-loaded biochar for the immobilization of arsenic, lead, and cadmium in a polluted soil system: Effects and mechanisms | |
| CN110560473B (en) | Method for stabilizing soil fluoride and arsenic | |
| CN111234827B (en) | Heavy metal contaminated soil remediation agent and preparation method and application thereof | |
| CN111085537B (en) | Method for restoring heavy metal contaminated soil by using organic phosphorus and inorganic phosphorus materials | |
| CN111676020B (en) | Composite soil remediation agent and preparation method and application thereof | |
| CN104531156B (en) | One kind repairs lead cadmium pollution soil fixative and its methods for making and using same | |
| CN111575011B (en) | Heavy metal contaminated soil composite remediation agent and application method thereof | |
| CN114160100B (en) | Preparation method and application of ferrous sulfide-loaded nitrogen-doped biochar based on multi-step ball milling | |
| CN111014275A (en) | Heavy metal soil remediation agent and application thereof | |
| CN110484276B (en) | Method and reagent for repairing chromium-contaminated soil by coupling nano iron-based composite material with hexavalent chromium reducing bacteria | |
| CN105733593A (en) | Microbe-assembly-synthesis-based arsenic polluted soil restoring and fixing agent, and preparation and application methods thereof | |
| CN113058983A (en) | Method for restoring chromium-polluted soil by biochar-loaded hematite-shewanella photovoltaic complex | |
| Bao et al. | Effect of fulvic acid co-precipitation on biosynthesis of Fe (III) hydroxysulfate and its adsorption of lead | |
| CN108929693A (en) | A kind of soil heavy metal combined passivator and its application method | |
| CN114832778A (en) | Shaddock peel biochar for adsorbing arsenic as well as preparation method and application thereof | |
| CN110484275B (en) | Method and reagent for repairing mercury and chromium deep polluted soil by using anaerobic sulfate reducing bacteria in cooperation with iron-based material | |
| CN110724535B (en) | Novel ecological garden greening soil remediation treatment agent and preparation method thereof | |
| CN110016345B (en) | Cadmium-reducing arsenic-stabilizing soil passivator and use method thereof | |
| CN111250052B (en) | Multi-group chelating magnetic hypha water purifying agent and preparation method and application thereof | |
| CN110643370B (en) | Heavy metal contaminated soil remediation agent | |
| CN107350283B (en) | Method for repairing heavy metal soil by using magnesium silicate-hydrothermal carbon composite material | |
| CN111548803B (en) | Soil conditioner and preparation method and application thereof | |
| CN112375575A (en) | Repairing agent for copper-cadmium polluted acid soil and preparation method thereof | |
| CN111253947A (en) | Passivator for repairing cadmium, lead and arsenic polluted soil of saline-alkali soil and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |