CN109231408B - Method for in-situ construction of nano-iron reaction zone - Google Patents
Method for in-situ construction of nano-iron reaction zone Download PDFInfo
- Publication number
- CN109231408B CN109231408B CN201811145314.5A CN201811145314A CN109231408B CN 109231408 B CN109231408 B CN 109231408B CN 201811145314 A CN201811145314 A CN 201811145314A CN 109231408 B CN109231408 B CN 109231408B
- Authority
- CN
- China
- Prior art keywords
- injection
- iron
- nano
- reaction zone
- well
- 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
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/70—Treatment of water, waste water, or sewage by reduction
- C02F1/705—Reduction by metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/002—Reclamation of contaminated soil involving in-situ ground water treatment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/06—Contaminated groundwater or leachate
Abstract
The invention relates to a method for forming a nano-iron reaction zone in situ, which comprises the following steps: in the polluted groundwater area, more than one pair of injection well pairs, namely an injection well A and an injection well B, are drilled near a pollution source along the groundwater flow direction, more than one observation well is drilled at the downstream of the pollution plume injection well, reducing reagent solution and iron source reagent solution are injected into the injection well A and the injection well B intermittently at equal time intervals, the change of iron content is monitored through the observation well after injection, and the injection is stopped when the expected effect is achieved. The two injection agent solutions have certain mobility underground, can perform oxidation-reduction reaction underground to form a reductive iron mineral environment taking nano zero-valent iron as a main product.
Description
Technical Field
The invention particularly relates to a method for constructing a reaction zone in situ, and particularly relates to a method for constructing a nano-iron reaction zone in situ.
Background
In situ reaction zone remediation is based on the artificial creation of a "zone" in the subterranean environment in which migrating contaminants are intercepted, fixed or degraded into harmless materials. A permeable contaminant treatment zone is formed underground by injecting a chemical reactant, in which the contaminants in the underground environment are intercepted and permanently fixed in the zone in one manner, and in which groundwater contaminants are chemically reacted with the injected chemical to effect removal in another manner.
The nano iron particles have the characteristics of small particle size (1-100nm), large specific surface area, strong reactivity and reduction capability and capability of releasing electrons in the oxidation process. The prior art shows that the material can effectively remove organic pollutants and inorganic pollutants in the environment, for example, Chinese patent CN108246795A discloses a preparation method of glassy state network nano iron powder for soil remediation, namely, mixed gel prepared from glass fiber and silica gel is used for coating nano iron particles for modification, so that the reduction efficiency of the material on chromium-polluted soil is improved. The nano-iron has the characteristics of high removal rate, low preparation cost, no secondary pollution and the like.
However, the nano iron has higher surface energy and is very easy to agglomerate in the preparation and migration processes, so that the nano iron is easily adsorbed in an underground medium in the actual soil and underground water remediation process and cannot effectively play a role, the underground medium is blocked, and the permeability coefficient is influenced. At present, the main modification methods aiming at the agglomeration problem comprise a carrier loading method and a dispersant coating method, namely, a material with better dispersibility is added in a loading or coating mode to increase the electrostatic repulsive force and the steric hindrance of the material so as to achieve the purpose of dispersion. In the prior art, a method for realizing remediation of a polluted site by adopting an in-situ injection mode of modified nano-iron is adopted, for example, Chinese patent CN101898823A discloses a method for in-situ remediation of nitrobenzene-polluted underground water by using a nano-iron slurry reaction zone. The method comprises the steps of injecting prepared nano iron slurry or starch modified nano iron slurry into an injection well which is drilled in underground water in advance, and monitoring target pollutants in the well in real time through a monitoring well. When the expected treatment effect is achieved, the pouring is stopped, the starch modified nano iron is used, so that the specific surface area of the material is increased, and the problem of easy agglomeration of the material is improved to a certain extent. However, a method for forming the nano-iron reaction zone in situ is not found so far, which indicates that the in situ injection of the reducing agent has certain significance for site remediation.
Disclosure of Invention
The invention aims to provide a method for constructing a nano-iron reaction zone in situ, aiming at the defects of the technology. Meanwhile, a method for preparing nano iron in situ is provided.
The purpose of the invention is realized by the following technical scheme:
a method for constructing a nano-iron reaction zone in situ is characterized by comprising the following steps:
a. in the polluted groundwater region, groundwater near a pollution source flows to an upstream position, at least one pair of reagent injection wells 1 is vertically drilled along the groundwater flow direction, the distance between an injection well A and an injection well B in each pair of injection wells 1 is 1-2m, at least one observation well 3 is drilled at a position 3-5m downstream of the pollution plume injection well 1, and the depths of the injection well 1 and the observation well 3 reach the bottom of an aquifer;
b. firstly, injecting a prepared reducing reagent solution into an injection well A, and injecting a prepared iron source reagent solution into an injection well B when the reducing reagent solution migrates to the position of the injection well B; injecting a reducing reagent solution and an iron source reagent solution intermittently and circularly at equal time intervals in the injection sequence of injecting into an injection well A and then injecting into an injection well B, wherein pulse type injection is adopted during injection; under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process;
c. and monitoring the iron content change through the observation well 3 in the filling process, monitoring the formation condition of the reaction zone in real time, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Step a, an aeration zone section and a bottom section of the injection well 1 are closed, and water outlet meshes are arranged in a water-containing layer section of the injection well 1.
Step b, the reducing reagent is tea extract, tea polyphenol or sodium borohydride, and the reducing reagent solution is prepared according to the following steps: according to the mass percentage, 90-98 percent of reducing agent is dissolved in 1-10 percent of deionized water to prepare reducing agent solution.
Preferably, 20-200g of reducing agent is dissolved in 2L of deionized water to prepare a reducing agent solution.
Step b, the iron source reagent is ferric chloride, ferric nitrate, ferrous chloride or ferrous sulfate, and the iron source reagent solution is prepared according to the following steps: according to the mass percentage, 1-6% of iron source reagent is dissolved in 94-98% of deionized water to prepare iron source solution.
Preferably, 20-100g of the iron source reagent is dissolved in 2L of deionized water to prepare an iron source reagent solution.
The upper limit of the concentration of the prepared nano-iron in the final reaction zone is 20 g/L.
Compared with the prior art, the invention has the beneficial effects that:
1. the method for constructing the nano-iron reaction zone in situ effectively solves the problems that nano-iron is easy to agglomerate after in-situ injection, blocks an injection well and an underground medium, is poor in mobility and the like. Tests show that when simulation is carried out in granular media with different sizes, namely coarse sand, medium sand and fine sand, the nano iron synthesized in situ by the method can achieve a good migration effect in the flowing process of underground water.
2. According to the method for constructing the nano-iron reaction zone in situ, after the solvent is injected, the solvent is diffused and migrated in underground pores due to the action of concentration difference and underground water flow, the size of the formed nano-iron particles is in a corresponding relation with the size of the pores, so that the nano-iron particles pass through the pores under the wrapping action of the water flow, namely, the nano-iron particles formed by the method can migrate in the pores with coarse sand, medium sand and fine sand as media under the hydrodynamic action.
3. The in-situ constructed nano-iron is obtained by directly pouring the solution into the underground and then carrying out redox reaction on the solution in the underground environment, is more convenient to operate compared with the method of directly injecting the prepared nano-iron particles, reduces the mechanical cost in the process of preparing the nano-iron by stirring to a certain extent, has low maintenance cost, can effectively reduce the cost and reduce the harm to the environment by adopting the plant extract as the reducing agent, and provides the possibility of large-scale in-situ preparation and use.
Drawings
FIG. 1 is a profile view of an injection well and an observation well of a method of constructing a nanoiron reaction zone in situ;
FIGS. 2a to 2d are schematic diagrams of a nano-iron reaction zone formed at different times in a tank simulation experiment using fine sand as a medium;
fig. 3 a-3 d are schematic diagrams of nano-iron reaction bands formed at different times in a tank simulation experiment with coarse sand as a medium.
In the figure, 1 is an injection well 2, 3 is underground water flow direction, 4 is an observation well and 4 is underground water level.
Detailed Description
The following detailed description is made with reference to the accompanying drawings and examples.
a. In the polluted groundwater region, groundwater near a pollution source flows to an upstream position, at least one pair of reagent injection wells 1 is vertically drilled along the groundwater flow direction, the distance between an injection well A and an injection well B in each pair of injection wells 1 is 1-2m, at least one observation well 3 is drilled at a position 3-5m downstream of the pollution plume injection well 1, and the depths of the injection well 1 and the observation well 3 reach the bottom of an aquifer;
b. firstly, injecting a prepared reducing reagent solution into an injection well A, and injecting a prepared iron source reagent solution into an injection well B when the reducing reagent migrates to the position of the injection well B; injecting reducing reagent solution and iron source reagent solution intermittently and circularly at equal time intervals in the injection sequence of injecting into the injection well A first and then injecting into the injection well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process;
c. and monitoring the iron content change through the observation well 3 in the filling process, monitoring the formation condition of the reaction zone in real time, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
The aeration zone section and the bottom section of the injection well are closed, and water outlet meshes are arranged on the water-containing layer section.
The reducing reagent is tea extract, tea polyphenol or sodium borohydride; the reducing agent solution was prepared as follows: dissolving a reducing reagent in deionized water to prepare a reducing agent solution, wherein the reducing agent solution comprises the following components in percentage by mass: 90% -98% of deionized water and 1% -10% of reducing reagent, and specifically comprises the following components: 20-200g of reducing agent is dissolved in 2L of deionized water to prepare a reducing agent solution.
The iron source reagent is ferric chloride, ferric nitrate, ferrous chloride or ferrous sulfate; the iron source reagent solution is prepared by the following steps: dissolving an iron source reagent in deionized water to prepare an iron source solution; the iron source reagent solution comprises the following components in percentage by mass: 94% -98% of deionized water and 1% -6% of iron source reagent, and specifically comprises the following components: 20-100g of iron source reagent is dissolved in 2L of deionized water to prepare iron source reagent solution.
The upper limit of the concentration of the prepared nano-iron in the final reaction zone is 20 g/L.
Example 1
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of folium Camelliae sinensis extract in 2L of deionized water to obtain folium Camelliae sinensis extract solution; 20-100g of ferric chloride is dissolved in 2L of deionized water to prepare ferric chloride solution.
Injecting the prepared tea extract solution into injection well A, and injecting the prepared ferric chloride solution into injection well B after 1 min; injecting tea extract solution and ferric chloride solution intermittently and circularly at equal time intervals in the sequence of injecting well A and then injecting well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
As shown in fig. 2 a-2 d, for the simulation migration experiment performed in the small simulation tank, the black part in the figure is the formation and migration of nano-iron with time, at the initial stage of injection, the reducing reagent solution starts to generate black nano-iron when moving to the injection well B, and under the combined action of the intermittent injection of the reagent solution and the transverse groundwater flow, the nano-iron continuously migrates along the direction of the groundwater flow, and it can be seen that the nano-iron formed in the system can well migrate in the fine sand medium.
Example 2
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g tea polyphenols in 2L deionized water to obtain tea polyphenols solution; 20-100g of ferric chloride is dissolved in 2L of deionized water to prepare ferric chloride solution.
Injecting the prepared tea polyphenol solution into an injection well A, and injecting the prepared ferric chloride solution into an injection well B after 1 min; injecting tea polyphenol solution and ferric chloride solution intermittently and circularly at equal time intervals in the sequence of injecting the well A first and then injecting the well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 3
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of folium Camelliae sinensis extract in 2L of deionized water to obtain folium Camelliae sinensis extract solution; iron nitrate solution was prepared by dissolving 20-100g of iron nitrate in 2L of deionized water.
Injecting the prepared tea extract solution into injection well A, and injecting the prepared ferric nitrate solution into injection well B after 1 min; intermittently and circularly injecting the tea extract solution and the ferric nitrate solution at equal time intervals in the injection sequence of injecting the well A first and then injecting the well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 4
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g tea polyphenols in 2L deionized water to obtain tea polyphenols solution; iron nitrate solution was prepared by dissolving 20-100g of iron nitrate in 2L of deionized water.
Injecting the prepared tea polyphenol solution into an injection well A, and injecting the prepared ferric nitrate into an injection well B after 1 min; injecting tea polyphenol solution and ferric nitrate intermittently and circularly at equal time intervals in the sequence of injecting the well A first and then injecting the well B, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 5
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of sodium borohydride in 2L of deionized water to prepare a sodium borohydride solution; 20-100g of ferrous sulfate is dissolved in 2L of deionized water to prepare a ferrous sulfate solution.
Firstly, injecting the prepared sodium borohydride solution into an injection well A, and after 1min, injecting the prepared ferrous sulfate solution into an injection well B; and (3) intermittently and circularly injecting the reducing agent and the iron source agent at equal time intervals in the injection sequence of the injection well A firstly and the injection well B secondly, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 6
In a transparent simulation groove filled with fine sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size is 500X 330X 30(mm), and the fine sand size is 0.09-0.15 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of sodium borohydride in 2L of deionized water to prepare a sodium borohydride solution; dissolving 20-100g of ferrous chloride reagent in 2L of deionized water to prepare a ferrous chloride solution.
Firstly, injecting the prepared sodium borohydride solution into an injection well A, and after 1min, injecting the prepared ferrous chloride solution into an injection well B; and (3) intermittently and circularly injecting the reducing agent and the iron source agent at equal time intervals in the injection sequence of the injection well A firstly and the injection well B secondly, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 7
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of folium Camelliae sinensis extract in 2L of deionized water to obtain folium Camelliae sinensis extract solution; 20-100g of ferric chloride is dissolved in 2L of deionized water to prepare ferric chloride solution.
Injecting the prepared tea extract solution into injection well A, and injecting the prepared ferric chloride solution into injection well B after 1 min; injecting tea extract solution and ferric chloride solution intermittently and circularly at equal time intervals in the sequence of injecting well A and then injecting well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
As shown in fig. 3 a-3 d, for the simulation migration experiment performed in the small simulation tank, the black part in the figure is the formation and migration of nano-iron with time, at the initial stage of injection, the reducing reagent solution starts to generate black nano-iron when moving to the injection well B, and under the combined action of the intermittent injection of the reagent solution and the transverse groundwater flow, the nano-iron continuously migrates along the direction of the groundwater flow, and it can be seen that the nano-iron formed in the system can well migrate in the coarse sand medium.
Example 8
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g tea polyphenols in 2L deionized water to obtain tea polyphenols solution; 20-100g of ferric chloride is dissolved in 2L of deionized water to prepare ferric chloride solution.
Injecting the prepared tea polyphenol solution into an injection well A, and injecting the prepared ferric chloride solution into an injection well B after 1 min; injecting tea polyphenol solution and ferric chloride solution intermittently and circularly at equal time intervals in the sequence of injecting the well A first and then injecting the well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 9
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of folium Camelliae sinensis extract in 2L of deionized water to obtain folium Camelliae sinensis extract solution; iron nitrate solution was prepared by dissolving 20-100g of iron nitrate in 2L of deionized water.
Injecting the prepared tea extract solution into injection well A, and injecting the prepared ferric nitrate solution into injection well B after 1 min; intermittently and circularly injecting the tea extract solution and the ferric nitrate solution at equal time intervals in the injection sequence of injecting the well A first and then injecting the well B, and adopting pulse type injection during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 10
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g tea polyphenols in 2L deionized water to obtain tea polyphenols solution; iron nitrate solution was prepared by dissolving 20-100g of iron nitrate in 2L of deionized water.
Injecting the prepared tea polyphenol solution into an injection well A, and injecting the prepared ferric nitrate into an injection well B after 1 min; injecting tea polyphenol solution and ferric nitrate intermittently and circularly at equal time intervals in the sequence of injecting the well A first and then injecting the well B, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 11
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of sodium borohydride in 2L of deionized water to prepare a sodium borohydride solution; 20-100g of ferrous sulfate is dissolved in 2L of deionized water to prepare a ferrous sulfate solution.
Firstly, injecting the prepared sodium borohydride solution into an injection well A, and after 1min, injecting the prepared ferrous sulfate solution into an injection well B; and (3) intermittently and circularly injecting the reducing agent and the iron source agent at equal time intervals in the injection sequence of the injection well A firstly and the injection well B secondly, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Example 12
In a transparent simulation groove filled with coarse sand medium, two reagent injection wells (A, B) are vertically drilled along the flow direction of underground water, the distance between the two reagent injection wells is 0.3m, and the injection wells are deep to an aquifer. The simulated slot size was 500X 330X 30(mm) and the grit size was 0.4-0.8 mm.
Preparing a reducing agent and an iron source agent:
dissolving 20-200g of sodium borohydride in 2L of deionized water to prepare a sodium borohydride solution; dissolving 20-100g of ferrous chloride reagent in 2L of deionized water to prepare a ferrous chloride solution.
Firstly, injecting the prepared sodium borohydride solution into an injection well A, and after 1min, injecting the prepared ferrous chloride solution into an injection well B; and (3) intermittently and circularly injecting the reducing agent and the iron source agent at equal time intervals in the injection sequence of the injection well A firstly and the injection well B secondly, wherein pulse type injection is adopted during injection. Under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process.
And observing the formation condition of the reaction zone through the transparent simulation tank in real time in the filling process, stopping filling until the nano-iron reaction zone reaches an expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone.
Claims (2)
1. A method for forming a nano-iron reaction zone in situ is characterized by comprising the following steps:
a. in the polluted groundwater region, groundwater near a pollution source flows to an upstream position, more than one pair of reagent injection wells (1) are vertically drilled along the groundwater flow direction, the distance between an injection well A and an injection well B in each pair of injection wells (1) is 1-2m, more than one observation well (3) is drilled at a position 3-5m downstream of a pollution plume injection well, and the well depths of the injection wells (1) and the observation wells (3) reach the bottom of an aquifer;
b. firstly, injecting a prepared reducing reagent solution into an injection well A, and injecting a prepared iron source reagent solution into an injection well B when the reducing reagent solution migrates to the position of the injection well B; injecting the reducing agent solution and the iron source agent solution into an injection well A and then injecting the reducing agent solution and the iron source agent solution into an injection well B at equal time intervals in an intermittent and cyclic mode, wherein pulse type injection is adopted during injection; under the mode of intermittent injection, the injection agent reacts in situ to form a plurality of connected small annular reaction zones, and under the action of concentration difference and underground water flow, the small annular reaction zones form a continuous nano iron reaction zone in the migration process;
the reducing agent solution is prepared by the following steps: dissolving 20-200g of reducing reagent in 2L of deionized water to prepare a reducing reagent solution, wherein the reducing reagent is a tea extract, tea polyphenol or sodium borohydride; the iron source reagent solution is prepared by the following steps: dissolving 20-100g of an iron source reagent in 2L of deionized water to prepare an iron source reagent solution, wherein the iron source reagent is ferric chloride, ferric nitrate, ferrous chloride or ferrous sulfate;
c. monitoring the iron content change through the observation well (3) in the filling process, monitoring the formation condition of the reaction zone in real time, stopping filling until the nano-iron reaction zone reaches the expected diffusion range, continuing monitoring after filling is stopped, and observing the stability of the nano-iron reaction zone;
the upper limit of the concentration of the prepared nano-iron in the final reaction zone is 20 g/L.
2. The method of claim 1, wherein the reaction zone comprises: step a, an aeration zone section and a bottom section of the injection well are closed, and water outlet meshes are arranged in a water-containing layer section of the injection well.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811145314.5A CN109231408B (en) | 2018-09-29 | 2018-09-29 | Method for in-situ construction of nano-iron reaction zone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811145314.5A CN109231408B (en) | 2018-09-29 | 2018-09-29 | Method for in-situ construction of nano-iron reaction zone |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109231408A CN109231408A (en) | 2019-01-18 |
| CN109231408B true CN109231408B (en) | 2021-10-01 |
Family
ID=65054529
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811145314.5A Active CN109231408B (en) | 2018-09-29 | 2018-09-29 | Method for in-situ construction of nano-iron reaction zone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109231408B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3870334A1 (en) * | 2018-10-26 | 2021-09-01 | Politecnico Di Torino | Method for producing zero-valent metals in filtering media |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101898823A (en) * | 2010-07-09 | 2010-12-01 | 吉林大学 | Method for in-situ restoration of nitrobenzene-polluted underground water through nano-iron slurry reaction zone |
| CN102807280A (en) * | 2012-08-30 | 2012-12-05 | 吉林大学 | Method for repairing polluted underground water based on Fenton class reagent of in situ iron |
| CN104857934A (en) * | 2015-05-21 | 2015-08-26 | 中国地质科学院水文地质环境地质研究所 | Method for preparing NZVI (nano-scale zero-valent iron) suspension from green tea as well as application of suspension |
| CN106145335A (en) * | 2015-04-08 | 2016-11-23 | 北京建工环境修复股份有限公司 | A kind of discontinuous permeable reactive wall repairs the system and method for polluted underground water |
| CN106966481A (en) * | 2017-05-17 | 2017-07-21 | 吉林大学 | The method that in-situ reducing repairs Polluted Groundwater |
| CN108046404A (en) * | 2017-12-20 | 2018-05-18 | 浙江省环境保护科学设计研究院 | A kind of in situ chemical oxidation restorative procedure of organic pollution underground water |
-
2018
- 2018-09-29 CN CN201811145314.5A patent/CN109231408B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101898823A (en) * | 2010-07-09 | 2010-12-01 | 吉林大学 | Method for in-situ restoration of nitrobenzene-polluted underground water through nano-iron slurry reaction zone |
| CN102807280A (en) * | 2012-08-30 | 2012-12-05 | 吉林大学 | Method for repairing polluted underground water based on Fenton class reagent of in situ iron |
| CN106145335A (en) * | 2015-04-08 | 2016-11-23 | 北京建工环境修复股份有限公司 | A kind of discontinuous permeable reactive wall repairs the system and method for polluted underground water |
| CN104857934A (en) * | 2015-05-21 | 2015-08-26 | 中国地质科学院水文地质环境地质研究所 | Method for preparing NZVI (nano-scale zero-valent iron) suspension from green tea as well as application of suspension |
| CN106966481A (en) * | 2017-05-17 | 2017-07-21 | 吉林大学 | The method that in-situ reducing repairs Polluted Groundwater |
| CN108046404A (en) * | 2017-12-20 | 2018-05-18 | 浙江省环境保护科学设计研究院 | A kind of in situ chemical oxidation restorative procedure of organic pollution underground water |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109231408A (en) | 2019-01-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109290350B (en) | Method for in-situ construction of nano ferrous sulfide reaction zone to restore polluted underground water | |
| Kocur et al. | Characterization of nZVI mobility in a field scale test | |
| CN110454132B (en) | Nano magnetofluid fracturing fluid imbibition oil increasing method for tight reservoir and modified nano magnetic particles | |
| Mohammadian et al. | Field-scale demonstration of in situ immobilization of heavy metals by injecting iron oxide nanoparticle adsorption barriers in groundwater | |
| CN113480284B (en) | Cement-based pollutant blocking grouting material and preparation method thereof | |
| CN113233570A (en) | Preparation method of sodium bentonite loaded zero-valent iron and application of sodium bentonite loaded zero-valent iron in treatment of composite polluted underground water | |
| CN104324938A (en) | Horizontal permeable reaction layer for soil remediation and soil remediating method | |
| CN109013678B (en) | Preparation method of porous silicon-coated zero-valent iron material for in-situ remediation of groundwater pollution | |
| CN109231408B (en) | Method for in-situ construction of nano-iron reaction zone | |
| Krok et al. | Remediation of zinc-contaminated groundwater by iron oxide in situ adsorption barriers–From lab to the field | |
| Lyon-Marion et al. | Simulation of magnetite nanoparticle mobility in a heterogeneous flow cell | |
| Bai et al. | Effect of pore size distribution and colloidal fines of porous media on the transport behavior of micro-nano-bubbles | |
| Hou et al. | Co-transport of uranyl carbonate and silica colloids in saturated quartz sand under different hydrochemical conditions | |
| Kaplan et al. | Retention of zero‐valent iron colloids by sand columns: Application to chemical barrier formation | |
| Muller et al. | Methods for delivery and distribution of amendments for subsurface remediation: a critical review | |
| US20090308816A1 (en) | In-situ precipitation through microbially mediated iron distribution and iron oxyhydroxide formation | |
| CN106745659A (en) | A kind of method of organo-chlorine pollutant in removal underground water | |
| US20220033283A1 (en) | Method for producing zero-valent metals in filtering media | |
| Nwachukwu | Prospective techniques for in-situ treatment and protection of aquifers: A sustainable hydrology review | |
| Reddy et al. | Transport and reactivity of lactate-modified nanoscale iron particles in PCP-contaminated soils | |
| Bai et al. | The seepage transport of heavy metal Pb through sand column in the presence of silicon powders | |
| WO2002040410A1 (en) | A remediation method of contaminated ground by injecting reactive material | |
| Bai et al. | The transport of solid particle suspension at different alkalinities in saturated porous media | |
| Yuesuo et al. | Co-transport of colloids and facilitated contaminants in subsurface environment | |
| CN111115785A (en) | Method for repairing mercury-polluted underground water |
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 |