CN-121988736-A - Zero-valent iron particle with shell and preparation method and application thereof

CN121988736ACN 121988736 ACN121988736 ACN 121988736ACN-121988736-A

Abstract

The invention relates to the technical field of radioactive pollution treatment, solves the problem of low pertechnetate fixing efficiency caused by easy agglomeration, passivation and weak anti-interference capability of traditional nano zero-valent iron in the prior art, and provides a zero-valent iron particle with a shell, a preparation method and application thereof. The method is applied to the treatment of water-soluble pertechnetate, on one hand, pertechnetate can be reduced to water-insoluble technetium dioxide, the removal rate of pertechnetate exceeds 98% in the pH range of 5.0-8.0, on the other hand, good reduction performance is still maintained in the interference environment of high organic matters, and on the other hand, the stability of reduction and fixation of the pertechnetate under the anoxic condition is over 150 days, so that the problems in the prior art are effectively solved.

Inventors

JI HAODONG
MA HAORAN
YU KAI
ZHU LIMIN
ZHANG KUO
ZHU MINGYE

Assignees

南燕生态环境研究实验室(深圳)有限公司
中交一公局集团有限公司
北京大学深圳研究生院

Dates

Publication Date: 20260508
Application Date: 20260205

Claims (10)

1. The zero-valent iron particle with the shell is characterized by being applied to reduction and fixation of pertechnetate, and comprises zero-valent iron particles and a stabilizer shell coated on the surface of the zero-valent iron particles, wherein the weight percentage of the stabilizer shell is 0.1% -0.5%, the particle size of the zero-valent iron particles is 10 nm-100 nm, and the stabilizer shell comprises carboxymethyl cellulose and/or water-soluble starch.
2. A method of preparing zero-valent iron particles with a shell according to claim 1, comprising: Pre-preparing a stabilizer solution based on a target mass percentage, and purging the stabilizer solution with an inert gas to remove dissolved oxygen, wherein the stabilizer solution comprises an aqueous carboxymethyl cellulose solution and/or an aqueous water-soluble starch solution; mixing and stirring the stabilizer solution and the precursor ferric salt solution in an inert gas filled environment to obtain a mixed solution; and (3) dropwise adding a reducing agent into the mixed solution for reduction reaction, and oscillating and standing the mixed solution to obtain a suspension containing the zero-valent iron particles with the shells.
3. The method for preparing zero-valent iron particles with shell according to claim 2, wherein the pre-formulating a stabilizer solution based on a target mass percentage and purging the stabilizer solution with an inert gas to remove dissolved oxygen comprises: Pre-preparing the stabilizer solution, and purging the stabilizer solution by using inert gas until the dissolved oxygen in the stabilizer solution is within a preset content range.
4. The method of preparing zero-valent iron particles with shell of claim 3, wherein pre-configuring the stabilizer solution comprises adding carboxymethyl cellulose and/or water-soluble starch to deionized water to form the stabilizer solution, wherein the target mass percentage is in the range of 0.1-0.5%.
5. The method for producing zero-valent iron particles with shell according to claim 2, wherein the mixing and stirring the stabilizer solution and the precursor iron salt solution in an atmosphere filled with inert gas to obtain a mixed solution, comprises: and mixing the stabilizer solution and the precursor ferric salt solution in an inert gas filling environment, wherein the temperature range of the mixing reaction is controlled to be 20-25 ℃, the stirring speed range is 400-800 rpm, and the concentration range of the precursor ferric salt solution is 10-30 millimoles per liter.
6. The method for producing the zero-valent iron particles with shell according to claim 2, wherein the step of dropping a reducing agent into the mixed solution to perform a reduction reaction, and oscillating and standing the suspension to obtain a suspension containing the zero-valent iron particles with shell, comprises: Determining the reducing agent amount for reducing the precursor ferric salt solution, and adding the reducing agent into the mixed solution based on the reducing agent amount to perform a reduction reaction, wherein the reduction reaction is performed under the oscillating condition, and the dripping time of the reducing agent does not exceed a preset time threshold; Oscillating the suspension based on a preset oscillation time period, and standing the suspension based on a preset standing time period.
7. The method for producing zero-valent iron particles with shell according to claim 6, wherein the determining the amount of the reducing agent for reducing the precursor iron salt solution and adding the reducing agent to the mixed solution based on the amount of the reducing agent to perform a reduction reaction comprises: and controlling the molar ratio of the precursor ferric salt solution to the sodium borohydride to be 1-2, and determining the reduction metering of the sodium borohydride based on the volume of the precursor ferric salt solution.
8. The method for producing zero-valent iron particles with shells according to any one of claims 2-7, characterized in that the inert gas comprises nitrogen, the precursor iron salt comprises a ferrous and/or a ferric salt, and the reducing agent comprises sodium borohydride.
9. The use of the coated zero-valent iron particles of claim 1, comprising configuring the coated zero-valent iron particles as a target suspension and adding the target suspension to a pertechnetate-containing liquid to be treated for reaction at a reaction temperature in the range of 20-25 ℃ and a pH in the range of 5.0-8.0.
10. The use of the zero-valent iron particles with shell according to claim 9, wherein the configuring the zero-valent iron particles with shell into a target suspension comprises: When the stabilizer shell is carboxymethyl cellulose, adding the zero-valent iron particles with the shell, wherein the mass concentration range of the zero-valent iron particles is 10-100mg/L, preparing the target suspension, when the stabilizer shell is water-soluble starch, adding the zero-valent iron particles with the shell, wherein the mass concentration range of the zero-valent iron particles with the shell is 60-100mg/L, preparing the target suspension, and when the stabilizer shell is carboxymethyl cellulose and water-soluble starch, adding the zero-valent iron particles with the shell, the mass concentration range of which is 10-100mg/L, preparing the target suspension.

Description

Zero-valent iron particle with shell and preparation method and application thereof Technical Field The invention relates to the field of radioactive pollution treatment, in particular to zero-valent iron particles with shells, and a preparation method and application thereof. Background Technetium-99 is a key radionuclide produced by the fission of uranium-235 or plutonium-239, technetium-99 being produced in large quantities mainly by atmospheric nuclear tests and spent fuel post-treatment and entering the environment. The nuclide has a half life as long as 2.14X10 5 years, has extremely strong environmental durability and forms a long-term potential threat to the ecosystem and human health. In the natural environment, technetium-99 mainly exists in the form of pertechnetate, and the form has high water solubility and strong migration, is extremely easy to diffuse and migrate in groundwater, and causes the pollution range to be continuously enlarged. In the prior art, nano zero-valent iron is widely used for reduction fixation of pertechnetate due to strong reducibility, and the core principle is that water-soluble pertechnetate is reduced to insoluble technetium dioxide, for example, chinese patent CN115228432A discloses that konjak glucomannan-derived carbon three-dimensional network is used for wrapping zero-valent iron, three-dimensional carbon network is used for adsorbing radioactive uranium, and zero-valent iron is used for reducing radioactive uranium and other nuclides. However, the traditional nano zero-valent iron has two technical bottlenecks in practical application, namely, the nano zero-valent iron is easily influenced by chemical conditions of underground water, such as pH value fluctuation, existence of bicarbonate, organic matter interference of humic acid and the like, so that the reaction activity is reduced, and the nano particles are easily agglomerated and the surface of the nano zero-valent iron is easily passivated, so that the reaction activity is quickly attenuated, and high-efficiency long-acting fixation of pertechnetate is difficult to realize. Disclosure of Invention In view of the above, the embodiment of the invention provides a zero-valent iron particle with a shell, and a preparation method and application thereof, which are used for solving the problems of easy agglomeration, passivation and weak anti-interference capability when nano zero-valent iron is used for pertechnetate reduction fixation in the prior art, so that the pertechnetate fixation efficiency is low. In a first aspect, the embodiment of the invention provides zero-valent iron particles with shells, which are applied to reduction and fixation of pertechnetate, wherein the zero-valent iron particles with shells comprise zero-valent iron particles and stabilizer shells coated on the surfaces of the zero-valent iron particles, the mass percentage range of the stabilizer shells is 0.1-0.5%, the particle size range of the zero-valent iron particles is 10-100 nm, and the stabilizer shells comprise carboxymethyl cellulose and/or water-soluble starch. In a second aspect, the embodiment of the invention provides the preparation method of the zero-valent iron particles with the shell, which comprises the steps of preparing a stabilizer solution in advance based on a target mass percentage, purging the stabilizer solution with inert gas to remove dissolved oxygen, wherein the stabilizer solution comprises carboxymethyl cellulose water solution and/or water-soluble starch water solution, mixing and stirring the stabilizer solution and a precursor ferric salt solution in an environment filled with the inert gas to obtain a mixed solution, dropwise adding a reducing agent into the mixed solution to perform a reduction reaction, and oscillating and standing the mixed solution to obtain a suspension containing the zero-valent iron particles with the shell. As an alternative embodiment, the pre-preparing the stabilizer solution based on the target mass percentage and purging the stabilizer solution with an inert gas to remove dissolved oxygen includes pre-preparing the stabilizer solution and purging the stabilizer solution with an inert gas until the dissolved oxygen in the stabilizer solution is within a preset content range. As an alternative embodiment, the pre-configuring the stabilizer solution comprises adding carboxymethyl cellulose and/or water-soluble starch into deionized water to form the stabilizer solution, wherein the target mass percent range is 0.8-1.2%. As an alternative implementation mode, the stabilizer solution and the precursor ferric salt solution are mixed and stirred in an inert gas filling environment to obtain a mixed solution, wherein the stabilizer solution and the precursor ferric salt solution are mixed in the inert gas filling environment, the temperature range of the mixing reaction is controlled to be 20-25 ℃ during the mixing process, the stirring rotating speed is controlled to be 400-