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CN-118788301-B - Zeolite adsorption film and preparation method thereof, combined sensor and synchronous test method for rhizosphere ammonia nitrogen and oxygen of aquatic plants

CN118788301BCN 118788301 BCN118788301 BCN 118788301BCN-118788301-B

Abstract

The invention belongs to the technical field of in-situ analysis of water environment interface elements and environmental parameters, and particularly relates to a zeolite adsorption film and a preparation method thereof, a combined sensor and a synchronous test method of aquatic plant rhizosphere ammonia nitrogen and oxygen. The zeolite adsorption film provided by the invention comprises agar hydrogel and zeolite particles dispersed in the agar hydrogel, wherein the particle size of the zeolite particles is less than or equal to1 mu m. The method can avoid ammonia nitrogen analysis interference caused by using the acrylamide material as a membrane matrix material, and can realize sub-millimeter-level high spatial resolution two-dimensional test of ammonia nitrogen by adopting a micro-cutting and micro-spectrophotometry analysis method of the zeolite adsorption membrane based on the zeolite particles with the particle size less than or equal to1 mu m. The zeolite adsorption film and the oxygen fluorescence sensing film are combined, so that synchronous testing of sub-millimeter two-dimensional distribution of ammonia nitrogen and oxygen at the rhizosphere environment interface of the aquatic plant is realized for the first time, sub-millimeter two-dimensional distribution images of the ammonia nitrogen and the oxygen at the same position of the rhizosphere are obtained, and an important basis is provided for revealing a response mechanism of the dynamic migration-absorption process of the rhizosphere ammonia nitrogen and the oxygen distribution.

Inventors

  • WU ZHIHAO
  • WANG SHUHANG
  • JIANG XIA
  • WANG KUN
  • CAI QING

Assignees

  • 中国环境科学研究院

Dates

Publication Date
20260508
Application Date
20240705

Claims (6)

  1. 1. The synchronous test method for the rhizosphere ammonia nitrogen and oxygen of the aquatic plant is characterized by comprising the following steps of: (1) Filling sediment, aquatic plants and overlying water in a root box, wherein the root box is provided with a detachable transparent side wall, stems and leaves of the aquatic plants are positioned in the overlying water, roots of the aquatic plants are positioned in the sediment, the aquatic plants are then cultivated in an experiment water tank, after the aquatic plants are cultivated successfully, a sensor is arranged on the inner surface of the detachable transparent side wall of the root box and in a region close to the roots of the aquatic plants, the sensor is a combined sensor, the combined sensor comprises a filter membrane, a zeolite adsorption membrane and an oxygen fluorescence sensing membrane which are arranged in a stacked manner, the zeolite adsorption membrane comprises agar hydrogel and zeolite particles dispersed in the agar hydrogel, the particle size of the zeolite particles is 1 mu m, and the oxygen fluorescence sensing membrane of the combined sensor is in contact with the detachable transparent side wall of the root box; (2) Testing the root box provided with the sensor in an experimental water tank; (3) Performing planar photoelectrode analysis on the oxygen fluorescence sensing film in the combined sensor obtained after the test to obtain a two-dimensional distribution image of the rhizosphere oxygen concentration of the aquatic plant, wherein the spatial resolution of the two-dimensional distribution image of the rhizosphere oxygen concentration of the aquatic plant is 62 mu m multiplied by 62 mu m; (4) Analyzing the ammonia nitrogen adsorption by using a zeolite adsorption film in the combined sensor after the planar photoelectrode detection to obtain a high-spatial-resolution two-dimensional distribution image of the ammonia nitrogen diffusion flux of the rhizosphere of the aquatic plant, wherein the ammonia nitrogen adsorption analysis comprises the following steps: Subjecting the zeolite adsorption film to cleavage of a spatial resolution of 200 μm×200 μm; Immersing the cut zeolite adsorption film slice in sodium chloride eluent for ammonia nitrogen elution, wherein the spatial resolution of the zeolite adsorption film slice is 200 mu m multiplied by 200 mu m, so as to obtain ammonia nitrogen eluent; and measuring the ammonia nitrogen concentration of the ammonia nitrogen eluent by adopting a sodium-based colorimetric method and a micro spectrophotometer of the ammonia nitrogen, and calculating the ammonia nitrogen concentration to obtain the diffusion flux of the ammonia nitrogen in the rhizosphere sediment.
  2. 2. The method for synchronously testing rhizosphere ammonia nitrogen and oxygen of aquatic plants according to claim 1, wherein the mass ratio of agar in the agar hydrogel to the zeolite particles is 1 (7-8).
  3. 3. The method for synchronously testing the rhizosphere ammonia nitrogen and the oxygen of the aquatic plants according to claim 1 or 2, wherein the ratio of the mass of agar in the agar hydrogel to the volume of water is 1g (42-50) mL.
  4. 4. The method for simultaneous testing of rhizosphere ammonia nitrogen and oxygen in aquatic plants according to claim 1, wherein the thickness of the zeolite adsorption film is 0.01-0.04 cm.
  5. 5. The method for simultaneous testing of rhizosphere ammonia nitrogen and oxygen in aquatic plants according to claim 1, wherein the method for preparing the zeolite adsorption membrane comprises the steps of: heating and mixing zeolite granule powder, agar and pure water to obtain a hot mixed solution; pouring the hot mixed solution into a mould for cooling, and demoulding to obtain the zeolite adsorption film.
  6. 6. The method for simultaneous testing of ammonia nitrogen and oxygen in rhizosphere of aquatic plants according to claim 5, wherein said initial gel film is obtained after said demolding, further comprising immersing and washing said initial gel film four times with ultrapure water to obtain said zeolite adsorption film.

Description

Zeolite adsorption film and preparation method thereof, combined sensor and synchronous test method for rhizosphere ammonia nitrogen and oxygen of aquatic plants Technical Field The invention belongs to the technical field of in-situ analysis of water environment interface elements and environmental parameters, and particularly relates to a zeolite adsorption film and a preparation method thereof, a combined sensor and a synchronous test method of aquatic plant rhizosphere ammonia nitrogen and oxygen. Background Aquatic plant rhizosphere of lake or other water body can absorb elements such as sediment nitrogen and phosphorus, thereby controlling sediment nitrogen endogenous load, and aquatic plants are applied to lake water body nutrition restoration engineering in a large number. Oxygen is generated by photosynthetic leaves and then is transported to leaves, stems and roots by aeration tissues, so that the rhizosphere of the aquatic plant can secrete oxygen to rhizosphere sediments, and the root oxidation zone is a protective layer of the root from toxin invasion and can influence geochemical reactions (nitrification and denitrification) of ammonia nitrogen. The anaerobic microenvironment is favorable for denitrification and reduction of dissimilated nitrate into ammonium reaction, and the nitrification reaction is inhibited. Thus, the rhizosphere redox environment affects the root zone sediment nitrogen geochemical reaction and the absorption of ammonia nitrogen by the rhizosphere. The two-dimensional high-spatial distribution of the ammonia nitrogen diffusion flux and the oxygen concentration of the rhizosphere micro-area is synchronously obtained, and the method has great significance in revealing the response relation between the ammonia nitrogen distribution and the oxygen of the rhizosphere micro-area and the migration-absorption dynamic process of the rhizosphere ammonia nitrogen. The current advanced method for testing the rhizosphere element and oxygen synchronous high spatial resolution of the aquatic plants is a combined test of a gradient diffusion film (DGT) technology and a planar Photopolar (PO) technology, namely, a DGT adsorption film, an oxygen fluorescence sensing film and a filter film are combined into one sensor, the sensor is placed in the rhizosphere test for 4-8 hours, a root box for cultivating the aquatic plants is placed in a planar photopolar test device, the two-dimensional distribution of the oxygen concentration of the rhizosphere is analyzed, then the sensor in the root box is taken out, the DGT adsorption film is taken out, and the two-dimensional analysis of the fixed element of the adsorption film is carried out. Finally, a two-dimensional image of the elemental diffusion flux and oxygen concentration distribution of the rhizosphere deposit is drawn. The current DGT adsorption film/oxygen fluorescent film combined sensor is mainly used for two-dimensional space analysis of rhizosphere inorganic phosphorus, metal elements and oxygen, such as a ZrO adsorption film/oxygen fluorescent film (used for analyzing two-dimensional distribution of inorganic phosphorus and oxygen), an SPR-IDA adsorption film/oxygen fluorescent film (used for analyzing two-dimensional distribution of metal elements and oxygen), and a ZrO-AT adsorption film/oxygen fluorescent film used for analyzing one-dimensional section of ammonia nitrogen/nitrate nitrogen/phosphorus and two-dimensional distribution of oxygen. Only one sensor, namely the ZrO-AT adsorption film/oxygen fluorescent film sensor described above, can test ammonia nitrogen and oxygen simultaneously. The ZrO-AT mixed adsorption film used consisted of three bonding agents, zrO, A-62MP and T-42H, and T-42H was used to test ammonia nitrogen. because the T-42H cation exchange resin particle diameter is >100 μm, T-42H or ZrO-AT adsorption membranes cannot be used for sub-millimeter two-dimensional spatial determination of ammonia nitrogen. DGT adsorbent membrane materials reported in the literature to date to be capable of measuring aquatic plant rhizosphere, sediment or water ammonia nitrogen include PrCH cation exchange resins, CMI-7000 cation exchange resins, and zeolites. The bonding reagent of the DGT adsorption film for testing ammonia nitrogen with two-dimensional high spatial resolution has the requirement that the particle diameter is less than or equal to 1 mu m, so that the subsequent two-dimensional ammonia nitrogen analysis with sub-millimeter resolution (100 mu m) can be performed. However, the particle sizes of the ammonia nitrogen adsorbing agents (T-42H, prCH and CMI-7000) are all larger than 100 μm. The zeolite adsorption film which has been developed successfully at present is prepared by mixing zeolite powder (particle diameter: 1 μm) with acrylamide glue and polymerizing, and the zeolite adsorption film is prepared by the method that the diameter of zeolite particles is qualified, but the amino in the adsorption film