CN-121990806-A - Preparation method of self-corrosion permeable pollutant blocking material for groundwater treatment

CN121990806ACN 121990806 ACN121990806 ACN 121990806ACN-121990806-A

Abstract

The invention provides a self-corrosion permeable pollutant blocking material for groundwater treatment and a preparation method thereof, belonging to the technical field of groundwater remediation. The self-corrosion permeable pollutant blocking material for groundwater treatment comprises, by mass, 25-35% of cement, 12-18% of 2CaSO 4 ·H 2 O, 8-15% of fly ash, 25-30% of graded pore-forming aggregate, 14-18% of nano pore-forming aggregate, 1-1.5% of viscosity modifier, 0.5-1% of early strength agent and 3-4.5% of modified biomass fiber, wherein a pore matrix is built by the graded pore-forming aggregate, the nano pore-forming aggregate and the modified biomass fiber together, the graded pore-forming aggregate and the nano pore-forming aggregate have self-corrosion shells, the pore-forming aggregate is inactive substances and does not participate in the reaction of silicate cement before grouting and in a hardening stage, and after the material is completely hardened, the graded aggregate and the nano pore-forming aggregate are converted into permeable pores containing active substances. The material has the advantages of good penetrability, strong supporting property, wide pollutant treatment capability, high pollutant treatment efficiency, strong continuous treatment time and the like, has anti-blocking capability, and can be pumped.

Inventors

WANG TIANQI
ZHANG XIAO
TIAN DONG
MA CHAOQUN
ZHOU XUEBIN
XU HANWEN
SUN SHASHA

Assignees

潍坊水动能科技产业研究院

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (8)

1. A self-corrosion permeable pollutant blocking material for groundwater treatment is characterized by comprising, by mass, 25-35% of cement, 12-18% of 2CaSO 4 ·H 2 O, 8-15% of fly ash, 25-30% of graded pore-forming aggregate, 14-18% of nano pore-forming aggregate, 1-1.5% of viscosity modifier, 0.5-1% of early strength agent and 3-4.5% of modified biomass fiber, wherein the sum of the contents of the raw materials is 100%; The graded pore aggregate is starch compound coated zero-valent iron particles, and the particle size of the zero-valent iron particles is 100-1500 microns; The nano pore-forming aggregate is pectin coated nZVI particles; the modified biomass fiber is prepared by softening, washing, drying and soaking biomass fiber in sodium hydroxide solution, washing and drying, calcining at a high temperature of 500-650 ℃ under the protection of inert gas, and crushing; The modified biomass fiber is prepared by mixing one or more of loofah sponge fiber, corn straw fiber, ox horn melon fiber and coconut shell fiber according to any proportion.
2. The self-dissolving permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the starch-based compound is G50 amylose 21%, G70 amylose 17%, G80 amylose 30%, glycerol 31%, sodium chloride 1%.
3. The self-dissolving permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the cement is one or more of PO52.5R type portland cement, PC52.5R type portland cement, SAC725R sulphoaluminate cement, mixed in any ratio.
4. A self-dissolving permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the 2CaSO 4 ·H 2 O is 200 ℃ calcined beta hemihydrate gypsum with a mesh size of 300 mesh.
5. The self-dissolving permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the fly ash is class C fly ash with a mesh size of 300 mesh.
6. The self-dissolved permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the viscosity modifier is one or more of ethylene-ethyl acetate copolymer, sodium silicate and polycarboxylate water reducer mixed in any proportion.
7. The self-corrosion permeable pollutant blocking material for groundwater treatment according to claim 1, wherein the early strength agent is one or more of lithium carbonate, calcium hydroxide, calcium formate, calcium chloride and aluminum chloride mixed in any proportion.
8. A method of preparing a self-eroding permeable contaminant blocking material for groundwater treatment according to claims 1-6, comprising the steps of: (1) The preparation method comprises the steps of cement, 2CaSO 4 ·H 2 O, fly ash, viscosity regulator and early strength agent; (2) The preparation of the graded pore-forming aggregate comprises the steps of coating zero-valent iron particles with starch compounds, preparing particles with the particle size of 100-1500 microns by the zero-valent iron in a vacuum negative pressure state, and freeze-drying in a nitrogen atmosphere at-40 ℃ to obtain the graded pore-forming aggregate; (3) Preparing nano pore-forming aggregate, namely preparing pectin coated nZVI particles into particles by water bath under the protection of nitrogen, and freeze-drying the particles in the nitrogen atmosphere at the temperature of-40 ℃ to obtain the nano pore-forming aggregate; (4) The modified biomass fiber material is prepared by softening one or more of loofah sponge fibers, corn straw fibers, ox horn melon fibers and coconut fibers for 8-24 hours, washing and drying, soaking in sodium hydroxide solution for 3-4 hours, washing with absolute ethyl alcohol and distilled water for 3-5 times, transferring into a tubular furnace, introducing nitrogen for protection, raising the temperature in the furnace to 500-650 ℃ at a temperature raising speed of 5-8 ℃ per minute, preserving heat for 2 hours, calcining at high temperature, and cooling to room temperature and crushing to obtain the modified biomass fiber material; (5) Cement, 2CaSO 4 ·H 2 O, fly ash, a viscosity regulator, an early strength agent, graded pore-forming aggregate and nano pore-forming aggregate are weighed, added with 0.32-0.35 of water of total mass and stirred to prepare slurry. And adding the modified biomass fibers into the slurry, uniformly stirring, and injection molding to obtain the self-corrosion permeable pollutant blocking material for groundwater treatment.

Description

Preparation method of self-corrosion permeable pollutant blocking material for groundwater treatment The invention relates to a preparation method of a self-corrosion permeable porous grouting material for groundwater treatment, belonging to the technical field of water pollution restoration. Background Multilayer goafs with complex structures appear in cities, a large number of mine roadways are abandoned, and pollutants remain. How to prevent and treat the diffusion of pollutants in the underground water and prevent the pollution of the underground water is an important subject to be solved in the present and future. The Permeable Reactive Barrier (PRB) is used as a common dyeing in-situ treatment technology in water pollution treatment, and is mainly formed by pre-screening or preparing materials for adsorbing and degrading water pollutant components, so that a wall type pollutant adsorption barrier is constructed, and pollution plumes permeate through a reaction medium under a natural hydraulic gradient. In recent years, water source pollution has shown a trend of complexity and diversity. Solving a plurality of complex pollutants is a focus of attention. And the continuous and sustainable reactive wall materials become the main development trend of in-situ repair technology. Patent CN116639851a discloses a multistage permeable reactive barrier, wherein the first-stage filling material is activated carbon for primary adsorption and oxidation treatment of pollutants, the second-stage filling material is O 3、KMnO4 and sodium persulfate for oxidation treatment of pollutants, and the third-stage filling material is lactic acid and pseudomonas B50D for treatment of pollutants by microorganisms. The three-stage treatment has better removal effect on various pollutants in the groundwater, but also has the problems of short service life and higher cost, and the three-stage treatment is mostly an open reaction wall, so that the treatment capability on the deep pollutants of the groundwater is limited. Patent CN113480284a discloses a cement-based pollutant blocking grouting material, which utilizes the delayed gas generation effect of modified aluminum-based gas generation particles in the cement material, so that the material can ensure grouting into deep groundwater pollution feather to form a porous material, thereby achieving the effect of purifying water body. It is easy to see that the cement pollutant blocking grouting material belongs to a post-gas-generating pore-forming material, the pore diameter, the morphology and the penetrability of pore-forming are affected by deep underground water pressure, temperature and pollutant types, and the inner pore diameter of the material is difficult to ensure to be the ideal morphology. Furthermore, the connectivity is difficult to ensure, and the pollutant treatment efficiency is low. In addition, the reaction wall blocking material based on the gas-generating porous cement-based skeleton has the problem of low material strength, and cannot guarantee the supporting effect of the pollution feather mine tunnel, so that the risk of mine collapse is increased. The pollutant treatment material can solve the problem of polluted water purification in experiments, but the treatment capacity of the pollutant treatment material is about to catch the forepart and break the elbow in the face of the problems of actual deep goafs, roadways with complex structures and easy collapse and superposition of multiple pollutants. In order to solve the above problems, a new grouting blocking material is needed, which has the advantages of good material penetrability, strong supporting property, wide pollutant treatment capability, high pollutant treatment efficiency, long continuous treatment time, certain blocking prevention capability and pumpability, so that the material can inhibit the diffusion of deep pollution sources at the source. Disclosure of Invention Aiming at the defects of the materials and combining with the needs of the practical engineering field, the invention provides a self-corrosion permeable pollutant blocking material for groundwater treatment, the material is injected into a low-pollution water channel through a concrete grouting or grouting technology, and when the slurry material reaches a designated plugging place, the material rapidly stones and develops strength, the scouring risk of the material is reduced, and the plugging support is carried out on the whole pollution feather tunnel and the cracks. Over time, the strength of the material is higher and higher, the interior is continuously washed, so that the surface of the pore-forming particles is eroded, the pores are exposed, size-communicated graded pores are formed, and active substances exist in the pores, so that sewage is purified. In order to achieve the technical purpose, the invention adopts the following technical scheme: The invention provides a self-corrosion permeable pollutant blocking mater