Soil salt-isolating material taking volcanic ash as carrier as well as preparation method and application of soil salt-isolating material

Abstract

The invention is applicable to the technical field of soil remediation, and provides a soil salt-isolating material taking volcanic ash as a carrier and a preparation method and application thereof, and the preparation method comprises the following steps: grinding volcanic ash particles, sieving, and uniformly mixing with deionized water; carrying out centrifugal treatment on the mixture, discarding supernate, washing and drying; adding the dried volcanic ash powder into 1% o wt of a silane coupling agent solution, fully and uniformly mixing, separating, filtering and drying; adding 3.5 wt% of m-phenylenediamine aqueous solution into the dried volcanic ash powder, uniformly mixing, standing, and pouring out redundant solution; adding 0.2 wt% of a trimesoyl chloride n-hexane solution into the volcanic ash powder, uniformly mixing, forming a polyamide film on the surface of the volcanic ash powder through an interfacial polymerization reaction, standing, pouring out the redundant solution, washing with deionized water, and drying; and solid substances are taken out and ground into powder. The problem that the polyamide membrane is difficult to be independently used in the soil environment is solved; the improvement effect of the whole material on the soil performance is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, and particularly relates to a soil salt barrier material with volcanic ash as a carrier, its preparation method, and its application. Background Technology

[0002] Soil salinization is a complex ecological and environmental problem involving the combined effects of natural factors and human activities. Affected by climate change and human factors, the situation of soil salinization is becoming increasingly severe, seriously threatening the quality of arable land and food security.

[0003] To address soil salinization, various technologies have been implemented, including planting salt- and alkali-tolerant crops, applying soil conditioners, and flushing salts. While these methods have yielded some results, they also present several problems and potential risks: First, the treatment costs are too high. Soil conditioners require significant investment and long-term use to suppress the re-salinization process in saline-alkali areas. Second, water demand is substantial. Early flushing methods were widely used due to their low cost, quick results, and ease of operation, but they suffer from excessive water consumption, pollution of water systems and groundwater resources, and unsuitability for arid regions. Planting salt- and alkali-tolerant plants can effectively improve saline-alkali land, transforming it into a "granary," but it also involves long improvement cycles and significant human and material resource investment. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a soil salt barrier material using volcanic ash as a carrier, thereby addressing the problems mentioned in the background art.

[0005] The present invention is implemented as follows: a method for preparing a soil salt barrier material using volcanic ash as a carrier includes the following steps: Step 1: Grind the volcanic ash particles and pass them through a 200-mesh sieve. Mix the sieved volcanic ash powder with deionized water and stir until homogeneous to obtain a mixture. Step 2: Centrifuge the mixture, discard the supernatant, wash repeatedly, and then dry to obtain dry volcanic ash powder; Step 3: Add the dried volcanic ash powder to a 1‰wt silane coupling agent solution, shake to mix thoroughly, then separate, filter and dry. Step 4: Slowly add a 3.5%wt aqueous solution of m-phenylenediamine to the dried volcanic ash powder from Step 3, stir thoroughly to mix evenly, and pour off the excess solution after standing. Step 5: Slowly add 0.2%wt benzotrimethylol chloride n-hexane solution to the volcanic ash powder obtained in step 4, stir thoroughly to mix evenly, and form a polyamide film on the surface of the volcanic ash powder through interfacial polymerization reaction. After standing, pour off the excess solution, rinse repeatedly with deionized water, and dry to constant weight. Step 6: Take out the solid material obtained in Step 5 and grind it into powder to obtain the soil salt barrier material with volcanic ash as carrier.

[0006] Another objective of this invention is to provide a soil salt barrier material using volcanic ash as a carrier, which is prepared by the above-described preparation method.

[0007] Another objective of this invention is to provide an application of a soil salt barrier material with volcanic ash as a carrier in the improvement of saline soil.

[0008] This invention, by loading a polyamide membrane onto volcanic ash powder, allows it to be stably dispersed and fixed in the soil during application, significantly improving the problem of polyamide membranes being difficult to use alone in soil environments. Simultaneously, the volcanic ash itself, as a carrier, possesses excellent adsorption and pore structure, forming a synergistic effect with the polyamide membrane, further enhancing the overall material's improvement effect on soil properties. This combination not only overcomes the technical bottleneck of directly applying polyamide in soil but also exhibits synergistic effects superior to using them independently. Attached Figure Description

[0009] Figure 1 SEM image of the soil salt barrier material provided in the embodiments of the present invention; Figure 2 FTIR image of the soil salt barrier material provided in the embodiments of the present invention; Figure 3 Water-soluble Na provided in the embodiments of the present invention + and Ca 2+ Line graph showing the change in content with the number of rinsing cycles; Figure 4 This is a schematic diagram of the device provided in an embodiment of the present invention; Figure 5 A soil moisture content distribution heatmap provided for an embodiment of the present invention; Figure 6 The soil pH value variation curves over time and depth provided in this embodiment of the invention are shown in the figure, where a is 7D, b is 14D, c is 30D, d is 50D, e is 80D, and f is 100D. Figure 7 The bar chart shows the soil electrical conductivity of the upper brown soil under different experimental days and depths provided in this embodiment of the invention, where a is 7D, b is 14D, c is 30D, d is 50D, e is 80D, and f is 100D. Figure 8 The bar chart shows the soil electrical conductivity of the lower saline soil under different experimental days and depths provided in the embodiments of the present invention, where a is 7D, b is 14D, c is 30D, d is 50D, e is 80D, and f is 100D. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0011] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0012] Example 1: A soil salt barrier material using volcanic ash as a carrier, comprising the following components: volcanic ash and polyamide loading. The preparation method of this soil salt barrier material includes the following steps: Step 1: Place the volcanic ash particles into the crushing tray, filling it to no more than two-thirds of its volume. After filling, place the tray into the vibrating crusher and fix it in place. Grind for 120 seconds. Step 2: Pass the powder ground in Step 1 through a 200-mesh sieve. Place the sieved volcanic ash powder and deionized water in a beaker and mix them evenly at a mass ratio of 1:5. Stir evenly under a constant temperature of 25 ℃. Step 3: Centrifuge the mixture obtained in Step 2 at 4000 r / min for 10 min, discard the supernatant, wash the volcanic ash powder with anhydrous ethanol, wash it repeatedly with deionized water, and finally dry it. Step 4: Take 50.0 g of the dried volcanic ash powder obtained in Step 3 and put it into 150 mL of a 1‰wt silane coupling agent solution (the silane coupling agent solution is a 1:900:100 mixture of ethanol and water of 3-aminopropyltriethoxysilane) and shake it at 180 r / min for 4 h to mix it thoroughly. Step 5: Separate, filter, and dry the volcanic ash powder treated with the silane coupling agent in Step 4; Step 6: Slowly add 50 mL of the prepared 3.5%wt m-phenylenediamine aqueous solution to the dried volcanic ash powder from Step 5, stir thoroughly to mix evenly, let stand for 30 min, and then pour out the excess solution. Step 7: Slowly add 50 mL of 0.2%wt benzoyl chloride n-hexane solution to the volcanic ash powder from step 6 and stir thoroughly to mix evenly. At this time, a polyamide film is formed on the surface of the volcanic ash powder through interfacial polymerization reaction. After standing for 30 min, pour off the excess solution. Step 8: After repeatedly rinsing the powder from step 7 with deionized water, dry it in a 60 ℃ oven until constant weight; Step 9: Take out the solid material obtained in Step 8 and grind it into powder to obtain the soil salt barrier material with volcanic ash as carrier; In this embodiment of the invention, the volcanic rock is waste residue produced during mining.

[0013] Performance Analysis: I. The soil salt barrier material prepared in Example 1 can be characterized by the following methods: 1. The soil salt-barrier material was analyzed using a JSM-7900F scanning electron microscope (SEM) manufactured in Kyoto, Japan. The surface morphology of the volcanic ash after polyamide loading was obtained as follows: Figure 1 As shown, the surface of the volcanic ash mineral exhibits a smooth and flat morphology. The mineral exists in an irregular blocky form. Polyamide can be observed adhering to the surface of the mineral in a highly folded layered form. Its surface morphology is rough, and the edges are irregularly serrated. The surface of the multi-layered polyamide layer has hollow spherical films of different sizes due to water loss and folding, which significantly enhances its specific surface area.

[0014] 2. To evaluate the functional group loading of soil salt-barrier materials, Fourier transform infrared spectroscopy (FTIR) was used to compare and analyze the functional group composition of volcanic ash and polyamide-loaded volcanic ash powder: FTIR results characterization as follows Figure 2 As shown, the volcanic ash material supported on polyamide belongs to a typical aromatic polyamide film structure: amide characteristic region: at 1643 cm⁻¹ -1 The peak represents the C=O stretching vibration of amide I band, at 1534 cm⁻¹. -1 The peak exhibits coupled vibrational peaks of NH in-plane bending (δN-H) and CN stretching (νC-N), belonging to the amide II band. The sharpness of the peak reflects the regularity of the molecular chain, indicating moderate crystallinity and no obvious hydrolysis; Aromatic ring vibration region: 1267 cm⁻¹ -1 It is an aromatic CNC stretching vibration, belonging to the amide III band, and also in the fingerprint area (1000-500 cm). -1 The weak characteristic peak at 3300 cm⁻¹ was used to identify the aromatic polyamide structure. -1 The broad peaks in the vicinity represent NH stretching vibrations, possibly accompanied by OH stretching, 3000-2800 cm⁻¹. -1 The weak peaks in this range suggest the possible presence of a -CH2 structure; in contrast, no obvious characteristic peaks were observed in the volcanic ash, only at 1000-1100 cm⁻¹. -1 The characteristic peaks of Si-O-Si silicate minerals appear at the interface, while the Si-O-Si peaks in the volcanic ash-loaded polyamide originate from the loading of silane coupling agents at the volcanic ash interface.

[0015] II. The soil salt barrier material prepared in Example 1 was applied to the treatment of soil in saline-alkali areas to achieve the effect of blocking salt migration, as detailed below: 1. The salt-barrier performance of the soil salt-barrier material in Example 1 was tested by leaching experiment: A 5 cm thick layer of quartz sand was laid at the bottom of the rinsing tube, followed by a 5 mm thick layer of salt-barrier material, and finally another 5 cm thick layer of quartz sand. The tube was rinsed 10 times with a salt solution (0.5 g / L NaCl + 0.05 g / L CaCl2) prepared with ultrapure water at a rate of 25 mL / 10 min. The rinsing solution was collected and filtered, and the Na+ content was measured using an atomic absorption spectrophotometer. + Ca 2+ content; The results are as follows Figure 3 As shown, under conditions of increased leaching cycles, the salt-blocking performance of volcanic ash is poor, particularly regarding Na+. + Without a barrier function, and with residual soluble salts in the minerals dissolving during the leaching process, the sodium content in the leachate increases. + The concentration was slightly higher than the eluent concentration (0.197 g / L) for Ca. 2+ The decrease in concentration is due to the physical adsorption effect of the porous structure of volcanic ash, which reduces the concentration of Ca. 2+ The concentration decreased slightly; this indicates that the soil salt-barrier material effectively prevents Na from entering the environment. + and Ca 2+ All exhibited good barrier properties and continuously delayed Na+ leaching during multiple rinsing processes. + and Ca 2+ The migration rate further demonstrates the superior functionality and stability of the salt barrier material.

[0016] 2. Analysis of the actual improvement effect on saline soil: Saline soil samples were collected from the saline soil region in the central and western part of Inner Mongolia Autonomous Region. The sampling point was a wasteland area in Bayannur City. The soil in this area suffered from severe salinization and compaction, poor soil structure, and poor water retention and aeration. The soil pH value was between 10.18 and 10.35. Good soil samples were collected from the black soil region of Chaoyang City, Liaoning Province. The sampling point was a cultivated area in Chaoyang City. The soil type in this area was brown soil, which is a cultivated soil with good texture and excellent structure. The collected soil samples were air-dried in a cool place, and stones, branches and other debris were removed. The soil was mechanically broken up to break up the large compacted soil clods. The soil samples were then passed through a 60-mesh sieve (0.25 mm) and bagged for later use. The two types of soil, after being sieved, were placed in an acrylic column 40 cm high, 10 cm in diameter, and with a 30 cm graduation mark (each marked with a 1.5 cm diameter sampling port every 3 cm) with the saline soil at the bottom and the brown soil on top. Figure 4As shown in the figure, the soil column was filled with a 1:1 volume ratio of saline soil to brown soil, denoted as KB. Volcanic ash powder was laid at a depth of 15 cm at the junction of saline soil and brown soil, denoted as CG. In another group, the soil salt barrier material prepared in Example 1 was laid at a depth of 15 cm at the junction of saline soil and brown soil, denoted as EG. Finally, a water tank was set at the bottom of the soil column. 1‰ salt water was added to the water tank. The distance between the water surface and the lower end of the saline soil layer was 5 cm to simulate the evaporation of groundwater under natural conditions, while keeping the moisture of the lower soil layer stable. The two groups of soil columns were placed in a dark place indoors for cultivation. Based on the data that the average annual rainfall in the central and western regions of Jilin Province is 400-500 mm, the rainfall conditions during the soil column cultivation process were calculated, and a leaching volume of 200 mL per week was selected as the simulated rainfall parameter. The salt isolation effect of the material was tested at 7, 14, 30, 50, 80, and 100 D. The salt-isolation effect of the tested soil was evaluated through the following aspects: (1) Soil moisture content: Soil moisture content refers to the soil's ability to adsorb and retain water under certain conditions. It is a key indicator of soil's physicochemical properties and directly reflects its hydraulic characteristics. Studies have shown that an increase in soil salt content leads to sudden structural degradation, destroying the original aggregate structure, reducing the soil's water retention and aeration performance, and thus affecting the soil's water and salt transport processes. Therefore, detecting changes in soil moisture content can directly reflect the impact of soil salt-barrier materials on soil quality and indirectly indicate their salt-barrier effect. The formula for calculating soil moisture content is: ; Soil wet weight: The weight of moist soil under natural conditions; Soil dry weight: The weight of moist soil after it has been dried to constant weight in an oven at 105℃; At D values ​​of 7, 14, 30, 50, 80, and 100, 10.0 g (accurate to 0.1 g) of soil samples were weighed for moisture content testing. The results were obtained using the formula described above. Figure 5 As shown; Figure 5The heatmap results show the changes in the soil water content distribution of the KB, CG, and EG groups at different experimental times and depths. In the first 7 - 14 D, the influence of rainfall factors is weak, and the change in soil water content is mainly regulated by the water evaporation - capillary action migration process. Due to the high salt content and poor soil structure of the lower - layer saline soil, the osmotic pressure of the soil aqueous solution is large, and the activity of soil water is enhanced, resulting in an upward migration trend with the increase of time and temperature. The water content distribution characteristics of the lower - layer saline soil (18 - 30 cm) are EG < KB < CG, and the water content distribution characteristics of the upper - layer cinnamon soil (0 - 15 cm) are EG > KB > CG. Since the volcanic ash added in the CG group absorbs the external rainfall and part of the water evaporation, the water content of the upper - layer soil is relatively low; in 14 - 50 D, with the accumulation of rainfall, the soil water content is greatly increased. Under the drive of osmotic pressure, the water - salt movement in the lower - layer soil with high salt content is more intense, and the evaporation rate is higher. The water content distribution characteristics of the lower - layer saline soil (18 - 30 cm) are EG < CG < KB, and the water content distribution characteristics of the upper - layer cinnamon soil (0 - 15 cm) are EG ≈ KB > CG. The salt - isolation layer in the EG group acts as a water buffer zone, maintaining the relative stability of the water content of the upper - layer soil while absorbing the water migrating from the lower - layer saline soil; in 80 - 100 D, the overall water content of the soil column has reached near - saturation. At this time, the water - salt dynamics are the strongest. Under the drive of the osmotic pressure of the soil solution in the upper and lower layers, the salt migrates upward with the water. Since the polyamide loaded on the volcanic ash in EG has an isolation effect on salts, an obvious water "barrier" is formed in the shallow layer, making it difficult for water to rise to the evaporation surface layer, thus synergistically reducing the driving force for salt upward migration. The water content shows that EG is slightly lower than the CG and KB groups.

[0017] (2) Changes in soil pH: The pH value of the soil is an indicator to measure the acidity and alkalinity of the soil. Studying the change of the soil pH value can not only test the barrier ability of the soil salt - isolation material to the alkali migration, but also, due to the coupling effect between the pH value and salt ions in the medium - high salt environment, the activity of salt ions can be judged by the change of the pH value; according to the operation specification of HJ 962 - 2018 "Determination of Soil pH Value - Potentiometric Method", a soil - to - liquid ratio of 1:2.5 is used, and a calibrated conductivity electrode is used for measurement. The results are as Figure 6 shown; Figure 6 The results reflect the change process of the soil pH value at different profile depths at 7, 14, 30, 50, 80, and 100 D. During the whole experiment, with the continuous action of factors such as rainfall and time, an upward change process can be observed for the pH of both groups. However, due to the addition of the soil salt - isolation material, the EG group is significantly lower than the KB and CG groups overall; In the KB group, the pH of the upper brown soil layer (0-15 cm) increased rapidly, from 7.89-8.31 at 7 days to 7.98-8.85 at 100 days. The curve showed a "cliff-like" drop at 15 cm and 18 cm before 14 days. After 14 days, the significant pH difference at the interface due to the different soil properties gradually decreased, and the curve became more consistent. The upper brown soil layer was significantly eroded by the lower saline soil, reaching a maximum of 9.7 at 50 days. The soil pH value clearly increased gradually with depth. The pH of the upper brown soil (0-15 cm) in the CG group increased slowly, from 7.93-8.37 at 7 D to 7.12-8.54 at 100 D. This was attributed to the dissociation of silicon-oxygen tetrahedra or aluminum-oxygen octahedra on the surface of volcanic ash, which has a certain alkali-blocking ability, but the overall effect and stability are weaker than those of the EG group. In the EG group, the pH of the upper brown soil layer (0-15 cm) remained stable, or even decreased slightly, from 7.59-7.85 at 7 days to 7.01-8.10 at 100 days. The pH of the lower saline soil layer (15-30 cm) changed only slightly and remained basically stable. It is worth noting that the 15 cm soil layer in EG is the depth at which the salt barrier material was added. It effectively and persistently distinguishes the pH of the upper and lower soil layers on a spatial scale, indicating that the added soil salt barrier material can effectively inhibit the alkaline erosion effect of the lower saline soil in the long term and exert the soil alkalinity barrier performance.

[0018] (3) Soil electrical conductivity: Total salt content in soil refers to the total amount of salts contained in the soil. Since various salts in soil leachate generally exist in the form of ions, total salt content can also be expressed as the sum of the amounts of various cations and anions in the soil leachate. Soil electrical conductivity is an indicator that reflects the content of dissolved salts in the soil and the conductivity of the soil aqueous solution, and can directly reflect the content of mixed salts. Selecting soil electrical conductivity as an evaluation parameter can most effectively and directly test the salt-barrier performance of soil salt-barrier materials. According to the operating procedure in HJ 802-2016 "Determination of Soil Electrical Conductivity by Electrode Method", a soil-to-liquid ratio of 1:5 was used, and a calibrated conductivity electrode was employed for measurement. During the measurement process, three parallel data points were measured for each sample, and the average value was taken as the final result. The measurement results are as follows: Figure 7 , 8 As shown; During the 7-14 D stage, the changes in soil electrical conductivity are mainly concentrated in the lower layer of saline soil. The upper layer of soil has not yet been eroded by the base ions that migrate from the lower layer with water evaporation and capillary action, and the changes in electrical conductivity shown are still within the normal range. During the 14-50 D stage, with the continuous accumulation of time and rainfall, the water-salt dynamics in the soil intensified, leading to increased vertical salt migration and subsequent erosion of the upper brown soil. In the KB group, soil electrical conductivity significantly increased at a depth of 12 cm at 14 D, while decreasing at 15 cm, consistent with the capillary transport mechanism at the interface between the two soil types. The CG group, through the porous structure of volcanic ash adsorbing upward-moving salt ions, limited the salt migration rate, stabilizing the electrical conductivity of the 3-12 cm soil layer, but simultaneously exhibiting a salt accumulation zone at 15 cm. The EG group, while maintaining relatively small fluctuations in the electrical conductivity of the upper brown soil layer, still inhibited salt migration from the lower saline soil layer, indicating that the salt barrier layer began to function. During the 50-100 D stage, significant changes occurred in the soil electrical conductivity of each group. Firstly, the electrical conductivity of the lower layer of saline soil in all three groups decreased substantially. At this point, the electrical conductivity of the EG group was significantly higher than that of the KB and CG groups. This phenomenon became more pronounced with increasing depth. This is because the salt transport pathways in the EG and KB / CG soil groups differ. In the EG group, salt accumulates, crystallizes, and settles in the capillary channels of the lower layer of saline soil after being continuously blocked by salt-sealing materials. In the KB group, however, salt in the lower layer of saline soil is continuously transported to the upper brown soil layer through evaporation, leading to a decrease in the electrical conductivity of the lower layer of saline soil. The electrical conductivity of the lower soil layer decreased because the volcanic ash layer acted as an accumulation zone for salt ions, adsorbing the salt ions that moved upward from the lower layer. Secondly, the electrical conductivity of the upper soil layer in the KB group increased significantly due to continuous salt erosion, and showed a regular pattern of continuous accumulation in the shallow layer. As time accumulated, when the amount of salt ions moving upward in the CG group exceeded the maximum adsorption capacity of the volcanic ash, the salt ions continued to move upward, causing the upper soil to become salinized. In contrast, the upper brown soil layer in the EG group remained stable and was not significantly affected by salt erosion. Only the contact layer at a depth of 12-15 cm showed a small change in electrical conductivity, indicating that the salt barrier layer continued to function. The above results demonstrate that the soil salt barrier material prepared in Example 1 can form a salt barrier layer, inhibit the migration rate of salt in the vertical direction, protect the upper soil from salt erosion, and maintain the stability of the electrical conductivity of the upper soil. At the same time, the change pattern of electrical conductivity is consistent with the change pattern of pH and water content, proving the effectiveness of the material.

[0019] In summary, the soil salt barrier material prepared using volcanic ash as a carrier according to the embodiments of the present invention has the characteristics of blocking salt migration, maintaining stable soil pH, and not affecting soil moisture exchange, and has certain application potential for soil salinization control. The recycling and reuse of volcanic ash-containing waste residue generated from mining also reflects the green and environmentally friendly concept of turning waste into treasure and reusing resources, as well as the invention concept of sustainable development.

[0020] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a soil salt-barrier material using volcanic ash as a carrier, characterized in that, Includes the following steps: Step 1: Grind the volcanic ash particles and pass them through a 200-mesh sieve. Mix the sieved volcanic ash powder with deionized water and stir until homogeneous to obtain a mixture. Step 2: Centrifuge the mixture, discard the supernatant, wash repeatedly, and then dry to obtain dry volcanic ash powder; Step 3: Add the dried volcanic ash powder to a 1‰wt silane coupling agent solution, shake to mix thoroughly, then separate, filter and dry. Step 4: Slowly add a 3.5%wt aqueous solution of m-phenylenediamine to the dried volcanic ash powder from Step 3, stir thoroughly to mix evenly, and pour off the excess solution after standing. Step 5: Slowly add 0.2%wt benzotrimethylol chloride n-hexane solution to the volcanic ash powder obtained in step 4, stir thoroughly to mix evenly, and form a polyamide film on the surface of the volcanic ash powder through interfacial polymerization reaction. After standing, pour off the excess solution, rinse repeatedly with deionized water, and dry to constant weight. Step 6: Take out the solid material obtained in Step 5 and grind it into powder to obtain the soil salt barrier material with volcanic ash as carrier.

2. The method for preparing soil salt-barrier material using volcanic ash as a carrier according to claim 1, characterized in that, In step 1, the mass ratio of the volcanic ash powder to deionized water is 1:4-6.

3. The method for preparing soil salt-barrier material using volcanic ash as a carrier according to claim 1, characterized in that, In step 2, the centrifugation of the mixture specifically involves centrifuging at 4000 r / min for 10 min.

4. The method for preparing soil salt-barrier material using volcanic ash as a carrier according to claim 1, characterized in that, In step 3, the 1‰wt silane coupling agent solution is an ethanol-water mixed solution of 3-aminopropyltriethoxysilane, and the mass ratio of 3-aminopropyltriethoxysilane, ethanol and water is 1:900:

100.

5. The method for preparing soil salt-barrier material using volcanic ash as a carrier according to claim 1, characterized in that, In step 3, the operation of oscillating to ensure thorough mixing specifically involves oscillating at a speed of 180 r / min for 4 hours to ensure thorough mixing.

6. A soil salt barrier material using volcanic ash as a carrier, characterized in that, It is prepared using the preparation method described in any one of claims 1-5.

7. The application of a soil salt barrier material with volcanic ash as a carrier as described in claim 6 in the improvement of saline-alkali soil.

8. The application according to claim 7, characterized in that, Includes the following steps: The soil salt barrier material is added to the required salt barrier depth, and after aging, it achieves the effect of salt barrier.

Images