CN111819944B

CN111819944B - Desalting method for repairing saline soil by combining plant bionic and salt crystallization inhibitor

Info

Publication number: CN111819944B
Application number: CN202010702817.9A
Authority: CN
Inventors: 赵英; 赵惠丽
Original assignee: Ludong University
Current assignee: Ludong University
Priority date: 2020-07-21
Filing date: 2020-07-21
Publication date: 2023-06-06
Anticipated expiration: 2040-07-21
Also published as: CN111819944A

Abstract

The invention relates to a desalination method for repairing saline soil by combining plant bionic and salt crystallization inhibitors. The desalination method comprises the following steps: taking out soil from top to bottom by utilizing an earth auger until the earth auger contacts groundwater, determining that the soil water interface is reached, and then driving a core straw into the interface of the soil to the groundwater from top to bottom; adding crystallization inhibitor iron ferricyanide solution at the surface. Effectively lighten the underground salt water and solve the problem of too high mineralization degree of the underground water.

Description

Desalting method for repairing saline soil by combining plant bionic and salt crystallization inhibitor

Technical Field

The invention relates to a desalination method for repairing saline soil by combining plant bionic and salt crystallization inhibitors.

Background

At present, the soil water and salt regulation measures are various, including various soil improvement, irrigation, hydraulic engineering and the like with the characteristics of water saving and salt control and green synergistic effect, and the core is to realize regulation and control by reducing evaporation to inhibit salt ascending (such as coverage), improving a soil structure to promote salt leaching (such as an improver), creating a barrier to block salt ascending (such as a barrier), or increasing soil drainage to accelerate soil salt drainage (such as a buried pipe) and the like. The physical improvement measures are to create a loose interlayer to inhibit salt from ascending through cultivation, powder ridge, straw interlayer and other methods. Under-film drip irrigation measures promote salt to be leached to the outer edge of the infiltration body along with water, so that a low-salt area is formed in the soil of the main root system layer, and salt avoidance of crops is facilitated. Hydraulic engineering measures such as concealed pipe drainage accelerate the drainage of soil salt at the lower boundary by increasing a net infiltration mode, and effectively reduce the salt content of the soil. In general, the current regulation methods need to combine different crop salinity thresholds and local soil types, so that the applicability of the regulation methods in saline-alkali agricultural production is clear, and the regulation methods have certain limitations.

In recent years, unexpected leakage of brine due to oil and gas development has become frequent. Oilfield brine consists essentially of sodium chloride with a conductivity exceeding 200dS m ^-1 Total dissolved solids exceeding 250g L ^-1 . Current in situ remediation strategies involve the incorporation of divalent cation-rich conditioning agents to displace monovalent sodium ions, which are then leached from the soil profile by rainfall and irrigation. However, in semiarid climates where the evaporation exceeds the precipitation, these methods generally have only limited results.

Current methods of treating salty soil rely on a combination of soil washing and phytoremediation, leaching in soil washing studies typically requires large amounts of water, and the texture is coarser, low clay content or potash fertilizer clay may promote leaching than potash anorthite clay which is less dispersible than smectic clay. The beneficial results of soil washing and phytoremediation may only be transient in fine-textured soil, as salt is still present below the rooting depth and salt re-encroachment into the rooting zone may occur due to capillary rise of salt-containing pore water.

Typically, straw capillary barriers are applied in strips to the soil (e.g., at a depth of 2/3 of the surface layer and maximum root depth) prior to crop planting, followed by conventional field management. The method has the problems of large field operation engineering quantity and higher cost, and the salt-blocking effect is invalid along with straw decomposition, so that the use effect and the cost are increased.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a desalting method for repairing saline soil by combining plant bionic and a salt crystallization inhibitor. The method can effectively lighten the underground salt water and solve the problem of too high mineralization degree of the underground water.

A desalination method for repairing salty soil by combining plant bionics and a salt crystallization inhibitor, wherein the steps of the desalination method comprise:

(1) Taking out soil from top to bottom by utilizing an earth auger until the earth auger contacts groundwater, and determining that the soil water interface is reached; then the core suction pipe is driven into the interface between the soil and the groundwater from top to bottom;

(2) Then adding crystallization inhibitor iron ferricyanide solution on the surface of the earth for desalting treatment.

Furthermore, the bionic material core straw is of a capillary structure and comprises a main core and a nylon net which is positioned at the periphery of the main core and used for packaging the main core.

Further, the main core is made of graphene material, ink stick or carbon-based material and super absorbent resin according to the weight ratio of 8:2 are mixed according to the proportion

Further, the bionic material core straw also comprises a semicircular glass material buckled at the top of the main core.

Further, the concentration of the ferric ferrocyanide solution is 0.00001 to 0.01M.

The beneficial effects are that:

1. the invention designs and prepares the soil desalting and wicking material by utilizing peat substances (graphene materials, ink sticks and carbon-based materials) to simulate a vascular bundle plant water absorption mechanism, and the material is directly driven into the ground water interface from top to bottom, so that groundwater and soil profile water salt are sucked into the soil surface layer, the ground water is continuously sucked into the soil through the bionic material by virtue of natural evaporation, the salt in the soil is effectively brought out of the ground surface through the water migration process, and the desalting effect is better. Compared with other water-salt regulation and control technologies, the plant bionic desalination method is a technology which can truly remove salt in soil and groundwater, and the salt still remains in the soil and groundwater by using other soil improvement technologies.

2. In order to prevent salt from crusting on the surface of soil and limiting the evaporation process, a crystallization inhibitor iron (III) ferrocyanide is added on the surface of the soil to promote the formation of dendritic crystal structures, ensure that underground salt can be continuously separated out from the surface of the soil, and improve the salt discharging capability.

3. The bionic desalting material not only can help to control salt in soil, but also is beneficial to improving soil fertility because the material is rich in soil nutrient components.

4. The bionic material is buried to penetrate through soil from top to bottom, and is also beneficial to improving soil structure, soil layer, soil hydrothermal distribution and pore condition.

5. Because the bionic material can absorb a large amount of water, the shape and the rigidity of the bionic material can be kept when the bionic material is wet, the bionic material also can meet the problem that salt which has been crystallized before is leached again due to the fact that the salt cannot be removed in time because rainfall or irrigation water enters a field occurs in the crop growth process, and mechanical desalting before, during or after crop planting can be facilitated.

6. Effectively lighten the underground salt water and solve the problem of too high mineralization degree of the underground water.

Drawings

FIG. 1 is a desalting flow chart, wherein (1) is a schematic diagram of the working principle of a bionic material core straw; (2) Schematic diagram of a mechanism of evaporating salt migration induced by a bionic material; (3) a bionic material actual effect diagram; (4) a structural schematic diagram of a single bionic material core straw.

Detailed Description

Example 1:

as shown in fig. 1, a desalination method for repairing salty soil by combining plant bionics and a salt crystallization inhibitor comprises the following steps:

(1) Taking out soil from top to bottom by utilizing an earth auger until the earth auger contacts groundwater, and determining that the soil water interface is reached; driving the bionic material core suction pipe into the interface between the soil and the underground water from top to bottom; the bionic material core straw comprises a main core, a nylon net (0.053 μm) positioned at the periphery of the main core and used for packaging the main core; the thinner bionic material core straw (diameter is 15 cm) is inserted into the water absorption device, and in the first stage, the water absorption is slower, and the water absorption is realized through the capillary absorption and dispersion effects; in the second stage, water molecules act on hydrophilic groups of the resin through hydrogen bonds, the hydrophilic groups are dissociated, an electrostatic repulsive force type resin network between ions expands, osmotic pressure is generated inside and outside the network, water is further infiltrated, core straw water is guided above the soil surface, and salt crystallization can be caused by evaporation on the surface.

The bionic material core straw can absorb a large amount of water by combining a bionic principle, keeps shape and rigidity when being wet, is biodegradable, and is not easy to degrade in a short period of time; the black color of the carbon-based material used by the core straw is beneficial to absorbing sunlight heat, improving heat and promoting evaporation; in addition, the bionic material core suction pipe also comprises a semicircular glass material buckled at the top of the main core, so that the condensation is further carried out, the evaporation degree of surface water is improved, and the fluidity of salt-water flow is further improved.

The main core material of the bionic material core straw adopts a carbon-based material and a super absorbent resin (Super Absorbent Polymer, SAP) according to the weight ratio of 8:2, and mixing the materials in proportion. The super absorbent resin is a novel functional polymer material, the components are mainly starch grafted acrylate, and the super absorbent resin is a water-retaining agent widely used in dry land water-saving agriculture and is directly purchased from chemical industry companies.

(2) The application of 0.00001 to 0.01M ferric ferrocyanide solution to the surface of a salinized soil, the crystallization inhibitor added to the system causes the soluble salts to bloom, thereby completely removing them from the soil, and mechanically desalting before, during, or after crop planting. Crystal inhibitors such as ferrocyanide affect the crystallization kinetics of sodium chloride, resulting in delayed efflorescence outside the soil and formation of dendritic crystal structures. Unlike salt crusting of the surface, the dendrites continue to interact with the water film in the soil pores to form capillary pumps, which can move rapidly upward as long as capillary connectivity is maintained, water and dissolved salt in the soil.

As shown in FIG. 1, the inventive wicking tube, like the fine porous vascular tissue of the plant root, draws saline from the reservoir into the saline contaminated soil macropores. Water is then drawn into the core, which forms a fine pore interface with the atmosphere above. When water molecules are attracted through the contaminated soil, their dipole character attracts free Na in the pore water ⁺ ，Cl ^- And a crystallization inhibitor applied to the surface. Solute and water are drawn into the surface core where the water is lost due to evaporation, resulting in concentration of the solute. The presence of inhibitors in the evaporation zone disrupts the crystallization behaviour of pure sodium chloride, leading to dendrite formation and growth, and thus continuing the evaporation process, rather than closing the evaporation surface.

According to the desalination method for repairing the salted soil by combining the plant bionic and the salt crystallization inhibitor, the bionic desalination material is distributed in the soil, the crystallization inhibitor ferric ferrocyanide is applied to the surface of the soil, the salt in the soil and the groundwater is removed by means of natural evaporation, the groundwater level is reduced, and a novel technology is provided for controlling the salt in the soil of a shallow buried region of the groundwater. The desalination and wicking peat material is manufactured by simulating a vascular bundle plant water absorption mechanism, is directly injected into a soil-underground water interface from top to bottom, continuously absorbs underground water into soil through natural evaporation, not only brings salt in the soil out of the ground surface through a water migration process, but also lightens underground salt water, solves the problem of overhigh mineralization of the underground water, has better desalination effect, and meets the actual condition and the requirement of improvement of saline farmland soil in an underground salt water area. Meanwhile, in order to prevent salt from crusting on the surface layer of the soil and limit the evaporation process, a crystallization inhibitor iron (III) ferrocyanide is added on the surface of the soil, so that the formation of a dendritic crystal structure is promoted, the underground salt can be continuously separated out from the surface of the soil, and the salt discharging capability is improved. In addition, because the bionic material can absorb a large amount of water, the shape and the rigidity of the bionic material can be kept when the bionic material is wet, the bionic material also satisfies the problem that salt which has been crystallized before is leached again due to the fact that the salt cannot be removed in time when rainfall occurs or irrigation water enters a field in the crop growth process, and can be used for mechanically desalting before crop planting, during the growth period or after harvesting.

The present invention may be summarized in other specific forms without departing from the spirit or essential characteristics thereof. The above-described embodiments of the invention are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. The desalting method for repairing the salty soil by combining the plant bionics and the salt crystallization inhibitor is characterized by comprising the following steps of:

(1) Taking out soil from top to bottom by utilizing an earth auger until the earth auger contacts groundwater, and determining that the soil water interface is reached;

driving the bionic material core suction pipe into the interface between the soil and the underground water from top to bottom;

the bionic material core suction pipe is of a capillary structure and has the diameter of 15 and cm, and comprises a main core, a nylon net positioned at the periphery of the main core and used for packaging the main core, and a semicircular glass material buckled at the top of the main core; the main core is made of graphene materials, ink sticks or carbon-based materials and super absorbent resin according to the weight ratio of 8:2, mixing and preparing the materials in proportion;

(2) Then adding a crystallization inhibitor ferrocyanide solution on the surface of the earth for desalting treatment;

the soil conductivity: 120 mS/cm, g NaCl/g oil 8%.

2. The desalination method of claim 1, wherein the concentration of the ferric ferrocyanide solution is 0.00001 to 0.01M.