Method for realizing anti-interference detection of trivalent arsenic based on cooperative regulation and control of chemical bonds
By using aminolated Fe2O3 nanosheets to form a synergistic bond with trivalent arsenic, combined with electrochemical enrichment and XRF analysis, the problem of trivalent arsenic detection in water was solved, and a high sensitivity and low cost detection effect was achieved, meeting the WHO detection standards.
Patent Information
- Application Number
- CN202510201570.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2025-05-13
AI Technical Summary
The prior art is difficult to effectively detect and remove trivalent arsenic (As(III)) in water, especially in the face of highly toxic, highly mobility and difficult to deal with groundwater environments, traditional methods have problems such as high cost, requiring professional operation, insensitive detection limits, and susceptibility to interference.
Functional nanomaterial-aminolated Fe2O3 nanosheets are used to form a synergistic bond with the ions to be measured, and efficient detection of trivalent arsenic in water environments is achieved through electrochemical enrichment and quantitative analysis of X-ray fluorescence spectroscopy (XRF).
It improves the detection sensitivity and linear detection range of trivalent arsenic, meets the World Health Organization (WHO) requirements for the lower limit of 10 ppb detection, effectively avoids common interference problems in electrochemical methods, and is simple in process and low in cost.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of X-ray fluorescence spectrum detection and analysis, and specifically relates to a method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds. Background Art
[0002] With the continuous improvement of production and living standards, the hidden dangers of water pollution to the living environment have gradually attracted widespread attention. Detection is the basis of governance. At present, large-scale instrument detection methods such as atomic absorption spectroscopy and inductively coupled plasma mass spectrometry are still regarded as mainstream analytical methods. This kind of precise detection often faces difficulties such as high cost and the need for well-trained professionals to operate, and is not conducive to rapid on-site analysis. As one of the classic means of ion analysis, electrochemical technology is often used for pollution monitoring in the environmental field, but in most cases, it needs to rely on precious metals and strong acid electrolytes, which is also a disadvantage that cannot be ignored. In addition, X-ray fluorescence spectroscopy (XRF) is also used for the detection and analysis of environmental pollutants, but there is a problem of insensitive detection lower limit.
[0003] Arsenic in nature exists mainly in two forms: trivalent As(III) and pentavalent As(V). As(III) is more toxic, about 60 times more than As(V), and has stronger mobility and is more difficult to remove. Generally speaking, As(III) is the dominant form of arsenic in groundwater. Commonly used unit technologies such as ion exchange, precipitation, and adsorption are difficult to treat As(III) to drinking water safety control standards (<10 ppb). Although the oxidation-adsorption process recommended by the US Environmental Protection Agency and other agencies has a good effect, it also has problems such as excessive oxidants, high costs, and secondary pollution (such as disinfection by-products). The literature Simultaneous Oxidation and Sequestration of As(III) from Water by Using Redox Polymer-Based Fe(III) Oxide Nanocomposite. Environmental Science & Technology (DOI:10.1021 / acs.est.7b00724) mentions an oxidation-adsorption functional coupled nanocomposite HFO@PS-Cl. This material achieves efficient oxidation of As(III) by covalently bonding active chlorine to the polystyrene carrier skeleton; and by fixing iron oxide nanoparticles in the carrier nanopores, it achieves exclusive adsorption and removal of oxidized As(V), thereby achieving efficient treatment of As(III) in water. The literature Electroadsorption-Assisted Direct Determination of Trace Arsenic without Interference Using Transmission X-ray Fluorescence Spectroscopy. Analytical Chemistry 2015, 87, 8503-8509 proposes an analytical technique based on electrosorption and transmission X-ray fluorescence (XRF) for quantitative determination of arsenic in aqueous solution at the limit of detection (LOD) at the ppb level. This method uses electrosorption to enhance the sensitivity and LOD of the arsenic XRF response. Amino-functionalized carbonaceous microspheres (NH 2 –CMS) was found to be an ideal material for quantitative adsorption and XRF analysis of arsenic. In electrosorption X-ray fluorescence (EA-XRF), arsenic is pre-concentrated by a conventional three-electrode system with a positive electric field around the adsorbent. Then, quantification of arsenic on the adsorbent is achieved using XRF. Compared with direct determination of arsenic solution by XRF alone, electrosorption pre-concentration can achieve rapid transfer of arsenic from solution to adsorbent and improve the LOD of conventional XRF. In the determination of arsenic, 0.09 cnt ppb was obtained without interference from coexisting metal ions.–1 The sensitivity of the method was tested and the LOD was found to be 7 ppb, which is lower than the 10 ppb arsenic guideline value given by the World Health Organization (WHO). The document uses the adsorption function of the protonated amino groups of amino carbon spheres in the design of nanomaterials. Since the interaction between carbon spheres and arsenic mainly comes from the electrostatic adsorption of protonated amino groups, the effect under the electric field is not enough to ensure the presence of neutral molecules in the form of H 3 AsO 3 Completely oxidized to anionic form H 2 AsO 4 - , H that has not been oxidized to anions 3 AsO 3 They cannot be electrostatically attracted to the amino carbon spheres, leading to potential inaccuracies in the results. Summary of the invention
[0004] The purpose of the present invention is to provide a functional nanomaterial-amino Fe 2 O 3 The synergistic bonding between the nanosheet and the ion to be detected realizes the method of anti-interference detection of trivalent arsenic in water environment. The present application firstly ultrasonically synthesizes the amino Fe with uniform morphology. 2 O 3 Nanosheets for directional H 3 AsO 3 The analyte is fixed on the electrode surface under the regulation of positive induction and different bonding between the electrode material and the target ion, and then the quantitative analysis of X-ray fluorescence spectrum is performed. Specifically, the present invention adopts the following technical scheme:
[0005] A method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds, wherein trivalent arsenic H is quantitatively detected by XRF after electrochemical enrichment in a test solution. 3 AsO 3 ; The electrochemical enrichment uses Ti sheets modified with amino nano-iron oxide as working electrodes.
[0006] In the above-mentioned method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds, it can be preferred that the preparation method of the amino-containing nano-iron oxide is: take 20 mg Fe 2 O 3 Dissolved in a solution consisting of 30 mL of ethanol and 2 mL of deionized water, then added with 2 mL of ammonia and 200 μL of APTMS (aminopropyltrimethoxysilane), ultrasonically treated for 2 h, oscillated at 200 rpm at room temperature for 2 h, then ultrasonically treated for 2 h, oscillated at 200 rpm at room temperature for 2 h; washed with deionized water several times to obtain amino-containing nano-iron oxide NH 2 -Fe 2O 3 .
[0007] In the above-mentioned method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds, it can be preferred that the Ti sheet modified with the amino nano-iron oxide is obtained by taking an amino nano-iron oxide liquid with a concentration of 2-3 mg / ml and uniformly dispersed by ultrasound, evenly dripping it on the surface of the polished Ti sheet, and air-drying it. The inventors have found that when the concentration of the selected amino nano-iron oxide liquid is too high, such as 4 mg / mL or more, the modified layer will be too thick, resulting in stacking of nanomaterials and coverage of active sites; and when the concentration of the selected amino nano-iron oxide liquid is too low, such as 1 mg / mL, the modified layer will be too thin to provide abundant active sites.
[0008] In the above-mentioned method for achieving anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds, it can be preferred that the electrochemical enrichment uses Ti sheet modified with amino nano-iron oxide as the working electrode, Ag / AgCl as the reference electrode, Pt wire as the counter electrode, the enrichment voltage is +1.5 V, and the enrichment time is 600 s.
[0009] As a preferred implementation method, the method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds described in the present invention may include the following steps:
[0010] (1) Preparation of amino-containing nano-iron oxide:
[0011] Take 20 mg Fe 2 O 3 Dissolved in a solution consisting of 30 mL of ethanol and 2 mL of deionized water, then added with 2 mL of ammonia and 200 μL of APTMS, ultrasonically treated for 2 h, oscillated at 200 rpm at room temperature for 2 h, then ultrasonically treated for 2 h, oscillated at 200 rpm at room temperature for 2 h; washed with deionized water several times to obtain amino-containing nano-iron oxide NH 2 -Fe 2 O 3 ;
[0012] (2) Amination of Ti sheets with nano-iron oxide modification:
[0013] Take 20 microliters of 2 mg / ml amino iron oxide liquid dispersed evenly by ultrasound, evenly drop it on the surface of the pretreated Ti sheet, and air dry it;
[0014] (3) Quantitative detection of trivalent arsenic H by XRF after electrochemical enrichment 3 AsO 3The electrochemical enrichment conditions are: Ti sheet modified with amino nano-iron oxide as working electrode, Ag / AgCl as reference electrode, Pt wire as counter electrode, enrichment voltage +1.5 V, and enrichment time 600 s.
[0015] In weakly acidic buffer solution, Fe 2 O 3 -NH 3 + With trivalent arsenic H 3 AsO 3 The special interaction of H significantly optimizes the XRF response signal. 3 AsO has a good linear detection range, and the theoretical detection limit meets the 10 ppb requirement proposed by WHO (Environmental Science & Technology, 2019, 53(10): 5596-5604). The elemental analysis method based on X-ray fluorescence spectroscopy (XRF) can also effectively avoid the signal suppression of the target dissolution peak by different ions in electrochemistry, effectively solving the interference problem. Combined with the DFT theoretical calculation results, the significantly different adsorption energies are used to reveal the different effects of nano-substrates on trivalent arsenic before and after functionalization, and the orbital coupling of Fe atoms and N atoms in functionalized nanomaterials is demonstrated. 3 AsO 3 The As atoms in the sample form bonds with O atoms (Fe-As bonds and NO bonds), which greatly improves the enrichment effect of target ions and thus improves the response signal of XRF, broadening the application prospects of X-ray fluorescence spectroscopy in ion detection.
[0016] According to the present invention, NH 2 -Fe 2 O 3 Modified electrodes to construct sensitive interfaces for trivalent arsenic H 3 AsO 3 The pre-enrichment of functional materials and target ions is used to improve the problem of the unsatisfactory detection limit of traditional XRF. The spectral response of energy dispersive XRF to characteristic elements is used to realize H in water environment. 3 AsO 3 This elemental analysis method effectively avoids the common Cu 2+ Interference hinders the dissolution of As signal.
[0017] In the existing research, the chemical synergy of trivalent arsenic enrichment by electrode-modified nanomaterials, the analysis of the specific mechanism by combining the atomic orbital matching between the substrate material and the analyte, and the application of this method in the detection of the X-ray fluorescence spectroscopic performance of trivalent arsenic have not been reported. 3 AsO3 In the enrichment stage, the synergistic effect of hydrogen bonding in the amino group and chemical bonding guided by Fe in the substrate material is used to fix the target species H on the electrode surface, which effectively improves the XRF detection performance and gets rid of the strong acidic conditions and precious metal catalysis commonly used in traditional electrochemical tests. The relevant mechanism of action is discussed in combination with the analysis of DFT theoretical calculations and experimental results, and it is found that the substrate after amino treatment is more sensitive to the target species H than the original substrate. 3 AsO 3 Amination of iron oxide with H 3 AsO 3 The interaction between the two is mainly reflected in the joint regulation of chemical bonding (Fe-As, NO). The special interaction between N and Fe in the substrate material and the target ions has led to the XRF method for H 3 AsO 3 This new approach to atomic interaction angles facilitates XRF methods for sensitive detection of H at the ppb level. 3 AsO 3 The detection performance is improved. The experimental process of this work is simple, low-cost, and has a competitive application prospect in the market. It enriches the detection ideas of heavy metal ions in water environment and provides an atomic-level explanation. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 NH prepared in Example 1 2 -Fe 2 O 3 SEM images of different sizes.
[0019] Figure 2 DFT adsorption configuration diagram (with adsorption energy). (a) Fe 2 O 3 For H 3 AsO 3 Adsorption configuration and adsorption energy of protonated NH 2 -Fe 2 O 3 For H 3 AsO 3 adsorption configuration and adsorption energy.
[0020] Figure 3 NH in Example 1 3 + -Fe 2 O 3 For H 3 AsO 3 XRF signal response diagram, and the inset is the corresponding linear fitting diagram.
[0021] Figure 4 is the NH prepared in Example 13 + -Fe 2 O 3 Adsorption H 3 AsO 3 Comparison of DOS orbital coupling between Fe-As and NO.
[0022] Figure 5 This is an anti-interference experiment for trivalent arsenic detection of the present invention. DETAILED DESCRIPTION
[0023] The following embodiments are further descriptions of the content of the present invention as an explanation of the technical content of the present invention, but the essential content of the present invention is not limited to the following embodiments. Ordinary technicians in this field can and should know that any simple changes or replacements based on the essential spirit of the present invention should fall within the scope of protection required by the present invention.
[0024] Example 1
[0025] (1) Amination of iron oxide NH 2 -Fe 2 O 3 The preparation process is as follows: First, Fe 2 O 3 (20 mg) was dissolved in ethanol (30 mL) and deionized water (2 mL), and ammonia (2 mL) and APTMS (200 μL) were added. Ultrasonic treatment for 2 h and shaking at room temperature (200 rpm) for 2 h were performed twice alternately. After washing with deionized water several times, NH 2 -Fe 2 O 3 . Figure 1 The SEM image of the amino iron oxide prepared in the example is given. It can be seen that the material is a uniformly dispersed hexagonal nanosheet structure with no obvious agglomeration phenomenon. The nanosheet size is 100-150nm and the thickness is 10-20nm. The introduction of amino groups is beneficial to the material's H 3 AsO 3 enhanced adsorption effect. Figure 2 The comparison gives Fe 2 O 3 Base material and NH 2 -Fe 2 O 3 For trivalent arsenic H 3 AsO 3 Adsorption configuration and adsorption energy of NH 2 -Fe 2 O 3 For H 3 AsO 3 The adsorption energy is lower than that of Fe 2 O3 For H 3 AsO 3 The adsorption energy of NH 2 -Fe 2 O 3 More conducive to H 3 AsO 3 The adsorption of ammonia-modified nano-iron oxide NH 2 -Fe 2 O 3 The nanosheet structure can exhibit better adsorption and catalytic properties in the present invention.
[0026] (2) Amination of iron oxide NH 2 -Fe 2 O 3 As the substrate, 20 microliters of amino iron oxide liquid with a concentration of 2 mg / ml dispersed evenly by ultrasound was evenly dropped on the surface of the pretreated Ti sheet and air-dried to obtain the Ti sheet modified with amino nano-iron oxide.
[0027] (3) The Ti sheet modified with amino-containing nano-iron oxide was used as the working electrode, Ag / AgCl as the reference electrode, and Pt wire as the counter electrode. The test solution (trivalent arsenic standard solution prepared with HAc-NaAc buffer solution at pH = 6) was electrochemically enriched. The HAc-NaAc buffer solution at pH = 6 was used as the electrolyte. The enrichment voltage was +1.5 V and the enrichment time was 600 s. Then, XRF was used to quantitatively detect trivalent arsenic H. 3 AsO 3 ; H was realized based on XRF method 3 AsO 3 Quantitative analysis of NH 2 -Fe 2 O 3 Under weakly acidic conditions, it is protonated to form NH 3 + -Fe 2 O 3 Enrichment of H under mild conditions 3 AsO 3 The obtained detection limits all meet the WHO requirements for trace detection in the environment. Figure 3 The method for H 3 AsO 3 Spectral response diagram. It can be seen that significant spectral signals can be obtained at concentrations as low as 10 ppb. At the same time, within a certain range, as the target H 3 AsO 3 As the concentration increases, the XRF signal becomes stronger. 3AsO 3 The concentration has a linear relationship, and its theoretical detection limit is 1.64 ppb, which meets the WHO requirements (10 ppb). Compared with the traditional direct detection of X-ray fluorescence spectroscopy (Environ. Sci. Technol. 55(19) (2021)13113-13121, Spectrometer, J. Pharm. Biomed. Anal. 189 (2020), Physiol. Meas.37(1) (2016) 145-161), the theoretical detection limit is increased by 2 orders of magnitude.
[0028] (4) The adsorption configuration and DOS results of DFT reveal the synergistic mechanism of bonding between nanomaterials and target ions. Figure 4 The orbital coupling of functionalized iron oxide and trivalent arsenic after bonding is given. Near the Fermi level, the Fe atoms in the nanomaterials and the target species H 3 AsO 3 The As atoms in the target species are orbitally coupled, and the N atoms in the nanomaterials are orbitally coupled to the H atoms in the target species. 3 AsO 3 The O atomic orbitals in the ions are coupled, and this energy level matching also explains the interaction between the substrate material and the analyte. Figure 5 It is an anti-interference experiment. It can be seen that the experimental conditions of the present invention effectively inhibit the Cu common in electrochemical detection. 2+ Interference, and Pb commonly found in XRF testing 2+ Interference, because the application of positive electric field hinders the aggregation of cations on the electrode surface, weakening the competition for occupying the active sites on the surface of the electrode material. And it has a similar structure to the target species SiO 3 2- and PO 4 2- The interference of the anti-interference detection was investigated, and the signal drop range of the anti-interference detection was less than 15%. This method has good anti-interference performance.
[0029] The present invention is based on mild conditions of weak acidity and proposes a Fe-based nano-substrate and the object to be tested at the atomic angle bond-assisted X-ray fluorescence spectroscopy (XRF) to detect trivalent arsenic H in water. 3 AsO 3 The present invention proposes a novel method for the synthesis of trivalent arsenic H 3 AsO 3 With NH 2 -Fe 2 O 3The interaction has led to a new method for spectral detection at the ppb level. Compared with the direct detection of traditional X-ray fluorescence spectroscopy, the detection limit of this method has been improved by two orders of magnitude. It is further combined with DFT theory to analyze the orbital coupling results between the elements, which illustrates the important influence of the synergistic regulation generated by the interaction between the amino nanomaterial substrate and the species to be tested in sensitive detection. 3 AsO 3 In the enrichment stage, functionalized substrate NH 2 -Fe 2 O 3 For trivalent arsenic H 3 AsO 3 The adsorption of trivalent arsenic H is due to the joint regulation of hydrogen bonding and chemical bonding, which ultimately produces sensitive spectral signals during XRF detection. DFT theoretical calculations help explain the detection of trivalent arsenic H in this work from the perspective of bonding. 3 AsO 3 This invention further expands the research methods of combining electro-enrichment and spectroscopy for water pollutants and provides a new way for the spectral detection of trivalent arsenic.
[0030] It should be noted that the above-mentioned technical contents of the present invention are only for explanation and clarification to enable those skilled in the art to understand the technical essence of the present invention, so the technical contents are not used to limit the substantial protection scope of the present invention. The substantial protection scope of the present invention shall be subject to the claims. Those skilled in the art should know that any modification, equivalent substitution and improvement based on the substantial spirit of the present invention shall be within the substantial protection scope of the present invention.
Claims
1. A method for anti-interference detection of trivalent arsenic based on the coordinated regulation of chemical bonds, which is to electrochemically enrich the sample in the test solution and then perform XRF quantitative detection of trivalent arsenic H3AsO3; the electrochemical enrichment uses a Ti sheet modified with amino-containing nano-iron oxide as the working electrode.
2. The method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds as claimed in claim 1, characterized in that: The preparation method of the amino-type nano-iron oxide is as follows: 20 mg of Fe2O3 is dissolved in a solution consisting of 30 mL of ethanol and 2 mL of deionized water, 2 mL of ammonia water and 200 μL of APTMS are added, ultrasonic treatment is performed for 2 h, and vibration is performed at 200 rpm at room temperature for 2 h, and then ultrasonic treatment is performed for 2 h and vibration is performed at 200 rpm at room temperature for 2 h; after washing with deionized water for multiple times, the amino-type nano-iron oxide NH2-Fe2O3 is obtained.
3. The method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds according to claim 1, characterized in that: The Ti sheet modified with amino nano-iron oxide is obtained by uniformly dropping an amino nano-iron oxide liquid having a concentration of 2-3 mg / ml and uniformly dispersing the liquid on the surface of the polished Ti sheet and air-drying the liquid.
4. The method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds according to claim 1, characterized in that: The electrochemical enrichment uses Ti sheet modified with amino nano-iron oxide as working electrode, Ag / AgCl as reference electrode, Pt wire as counter electrode, supporting electrolyte is HAc-NaAc buffer solution with pH=6, enrichment voltage is +1.5 V, and enrichment time is 600 s.
5. The method for realizing anti-interference detection of trivalent arsenic based on coordinated regulation of chemical bonds according to any one of claims 1 to 4, characterized in that: The steps include: (1) Preparation of amino-containing nano-iron oxide: Take 20 mg of Fe2O3 and dissolve it in a solution consisting of 30 mL of ethanol and 2 mL of deionized water, then add 2 mL of ammonia water and 200 μL of APTMS, ultrasonically treat for 2 h, oscillate at 200 rpm at room temperature for 2 h, then ultrasonically treat for 2 h, oscillate at 200 rpm at room temperature for 2 h; after washing with deionized water several times, amino-containing nano-iron oxide NH2-Fe2O3 was obtained; (2) Amination of Ti sheets with nano-iron oxide modification: Take 20 microliters of 2 mg / ml amino iron oxide liquid dispersed evenly by ultrasound, evenly drop it on the surface of the pretreated Ti sheet, and air dry it; (3) Electrochemical enrichment was followed by XRF quantitative detection of trivalent arsenic H3AsO3; the electrochemical enrichment conditions were: Ti sheet modified with amino-containing nano-iron oxide as the working electrode, Ag / AgCl as the reference electrode, Pt wire as the counter electrode, HAc-NaAc buffer solution with a pH of 6 as the supporting electrolyte, and an enrichment voltage of +1.5 V. The enrichment time was 600 s.