CN-122010240-A - Mechanical energy driving integrated uranium extraction system and method based on piezoelectric porous medium

CN122010240ACN 122010240 ACN122010240 ACN 122010240ACN-122010240-A

Abstract

The invention discloses a mechanical energy driven uranium extraction system and method based on a piezoelectric porous medium, and belongs to the technical field of functional materials and water treatment. The invention uses a porous medium (such as polyvinylidene fluoride porous membrane) with intrinsic piezoelectric activity as a core functional unit, and no adsorption functional group or catalytic active component is required to be added. When a water body containing uranyl ions (U (VI)) passes through the medium in a dynamic flow mode such as pulse, the fluid kinetic energy can excite the medium to generate a strong built-in electric field, and the flowing U (VI) can be directly reduced into insoluble uranium dioxide in situ. The invention also provides a preparation method of the piezoelectric porous medium, which is characterized in that the material has a porous structure and high-voltage electricity simultaneously by combining a phase conversion process with a crystalline phase regulator to induce self-polarization or by post-polarization treatment. The technology has the advantages of high efficiency, simplicity, large-scale preparation and application, and the like, and is particularly suitable for efficiently recycling uranium from seawater or uranium-containing wastewater.

Inventors

KONG XIAO
WANG YEFEI
CHANG YANJIAO
WANG CHENGLONG
WU PING
ZHOU DANDAN

Assignees

江苏海洋大学

Dates

Publication Date: 20260512
Application Date: 20260116

Claims (14)

1. A method for extracting and fixing uranium from a uranium-containing water body, comprising the steps of: Passing a body of water containing uranyl ions (U (VI)) through a piezoelectric porous body in a dynamic flow manner; wherein the dynamic flow forms dynamic mechanical stimulation on the piezoelectric porous body to generate a bulk built-in electric field inside the piezoelectric porous body; the uranyl ions (U (VI)) in the water body are directly reduced into insoluble U (IV) compounds by the built-in electric field of the bulk phase when flowing through the piezoelectric porous body and deposited in the piezoelectric porous body.
2. The method of claim 1, wherein the piezoelectric porous body is a piezoelectric porous membrane.
3. A piezoelectric porous membrane for extracting target metal ions from a fluid, characterized by being composed of a piezoelectric polymer, the membrane having a perforated porous structure; The membrane is configured to generate a built-in electric field inside its membrane body for directly reducing target metal ions flowing therethrough when subjected to dynamic mechanical stimulus.
4. The piezoelectric porous membrane of claim 3, wherein the piezoelectric polymer comprises at least one of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-tetrafluoroethylene, polylactic acid.
5. The piezoelectric porous membrane of claim 4, wherein the piezoelectric polymer is PVDF.
6. The piezoelectric porous membrane of claim 5, wherein the PVDF has a β crystal phase as a main crystal phase.
7. The piezoelectric porous film according to claim 6, wherein the relative content of the β crystal phase in the film is not less than 60%.
8. The piezoelectric porous membrane according to any one of claims 3 to 7, wherein the membrane has self-polarizing properties.
9. A method of preparing the piezoelectric porous membrane of claim 3, comprising the steps of: s1, providing a casting solution, wherein the casting solution comprises a piezoelectric polymer and a solvent; S2, subjecting the casting film liquid to a phase inversion process to form a gel film with a porous structure; and S3, performing post-treatment on the gel membrane to obtain the piezoelectric porous membrane.
10. The method of claim 9, wherein the casting solution further comprises a crystalline phase modulator capable of inducing the piezoelectric polymer to form a beta-phase based crystalline structure.
11. The method according to claim 10, wherein the crystallization phase regulator is at least one selected from the group consisting of an ionic surfactant and a hydrogen bond regulator.
12. The method according to claim 9, wherein in step S3 the post-treatment comprises drying the gel film, optionally before or after drying, further comprising the step of polarizing the film.
13. A uranium extraction system, comprising: The piezoelectric porous membrane of any one of claims 3 to 8; A fluid drive device configured to dynamically flow a uranium-containing water body through the piezoelectric porous membrane and to cause dynamic mechanical stimulation of the membrane.
14. The uranium extraction system of claim 13, wherein the dynamic flow regime is such that the uranium containing water body passes through the membrane in the form of pulsed flow, oscillatory flow or controlled turbulence.

Description

Mechanical energy driving integrated uranium extraction system and method based on piezoelectric porous medium Technical Field The invention belongs to the technical field of functional materials and water treatment, and particularly relates to a piezoelectric material for extracting and fixing uranium from a water body, a preparation method and an application system thereof. In particular, the present invention relates to a porous polymer medium with piezoelectric activity that can drive efficient reduction and deposition of uranyl ions using only fluid mechanical energy. Background Uranium is an important strategic resource and has important application in various fields such as clean energy, nuclear weapons and the like. Because of limited reserves of uranium in land, extraction of uranium resources from various water bodies is a current research hotspot. Adsorption, photo/electro-catalytic reduction, etc. are currently the main methods for extracting uranium from aqueous solutions, but the above methods face the dilemma of being difficult to combine in terms of scale-up application and uranium extraction performance. The fiber and membrane based adsorption material has the problems of low adsorption efficiency, poor selectivity and the like although the fiber and membrane based adsorption material can be prepared and applied in a large scale, and the photoelectric/electro-catalysis method has the problems of difficult preparation and application in a large scale, poor selectivity and the like of a core material although the uranium extraction efficiency is high. The separation membrane has the advantages of high specific surface area, adjustable pore structure and the like, and if the separation membrane can be made of a material with catalytic reduction characteristics, separation mass transfer and uranium reduction are coupled together, so that the separation membrane can be promoted to be applied to the field of uranium extraction in a large scale. Through retrieval, chinese patent document CN119455910A discloses a preparation method of an anti-fouling high-voltage catalytic activity polyvinylidene fluoride (PVDF) uranium adsorption material, which uses PVDF as a base material, blends amidoxime (PAO) functionalized polyacrylonitrile and Bi 4Ti3O12/SnO2 piezoelectric heterojunction in casting solution, prepares a PVDF membrane through a freezing phase inversion technology, and is applied to removal of uranium in water. The Bi 4Ti3O12/SnO2 piezoelectric heterojunction is subjected to external vibration to generate piezoelectric electrons, so that U (VI) subjected to reduction adsorption can be obtained into insoluble U (IV), and uranyl ions are separated from the solution and have excellent antibacterial performance. The technology has the remarkable limitations that firstly, the design thought is still in a 'functional grafting' model, PVDF is only used as a mechanical support body and does not have an active uranium extraction function, secondly, uranium must be captured in advance by relying on external chemisorption sites such as PAO and the like, the process is still limited by adsorption dynamics, thirdly, the piezoelectricity catalytic activity of the technology completely depends on external heterojunction particles, the piezoelectricity performance of a PVDF body is not effectively utilized, and the structure is complex and the cost is high. The comparative example of this patent also demonstrates that pure PVDF membranes without PAO added with piezoelectric heterojunction do not possess significant uranium extraction properties, reflecting the cognitive limitations of the prior art on PVDF-just considering it as an inert substrate. In summary, the existing uranium extraction technology generally falls into a dilemma that either chemical adsorption is relied on but in-situ solidification (such as a chemical adsorption method) is not possible, or the preparation cost of a catalytic reduction material is high, and large-scale preparation and application are difficult. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a uranium extraction solution which is subverted in principle, simple in structure, low in cost and truly integrated. The invention abandons the traditional concept of 'inert substrate + function grafting', discovers and utilizes the intrinsic characteristics of the pure polymer material with specific structural morphology, which are not recognized, for the first time, and realizes 'through-the-reduction' uranium extraction driven by mechanical energy only. The invention has the core concept that a piezoelectric film with self-polarization property, high beta crystal phase content and graded through porous structure is prepared by precisely regulating and controlling the microstructure and crystal phase of a polymer film, when uranium-containing fluid flows through the film in a dynamic mode (such as pulse flow), microscopic deformation