A method for preparing Fe2O3@ZnO composite material and enriching trace arsenic and mercury

Abstract

The application relates to the technical field of solid phase extraction, in particular to a method for preparing Fe2O3@ZnO composite materials and enriching trace arsenic and mercury, Fe2O3@ZnO composite materials are prepared by a hydrothermal method, and the Fe2O3@ZnO composite materials are applied to solid phase extraction pre-enrichment of As(III) and Hg(II) bimetallic ions. The analysis results of FT-IR, XRD and SEM show that under the conditions that the synthesis reaction pH is 5, the zinc-iron ratio is 3:1, the sodium citrate content is 6mmol, the reaction time is 16h, and the reaction temperature is 140 DEG C, the recovery rates of the solid phase extraction adsorbent for trace As(III) and Hg(II) can reach 97.99% and 98.43% respectively. The Fe2O3@ZnO composite materials prepared by the application have the advantages of simple synthesis method, high enrichment efficiency and wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of solid-phase extraction technology, specifically to a method for preparing Fe2O3@ZnO composite materials and enriching trace amounts of arsenic and mercury. Background Technology

[0002] Arsenic is widely distributed in nature in various forms, commonly including inorganic and organic arsenic. In aquatic environments, arsenic mostly exists in inorganic forms, such as As(III), As(V), and arsenite (AsO3). 3- ) and arsenate (AsO4) 3- Arsenic (As(III)) is a potent carcinogen, causing skin cancer, liver cancer, and vascular diseases. Long-term consumption of groundwater containing arsenic can cause irreversible damage to the human body.

[0003] Mercury exists in many forms, with inorganic mercury primarily existing as Hg. 2+ Hg + Hg 0 Existence, Hg 2+ It is mostly found in soil and aquatic environments, while Hg+ is unstable and mostly exists as Hg2. 2+ Hg exists in the form of 0 Inorganic mercury is mostly found in the atmosphere. Due to its low solubility in intestinal fluid, low permeability to biological membranes, and weak toxicity, inorganic mercury is more prevalent in the atmosphere. Organic mercury, on the other hand, is primarily in the form of methylmercury (CH3Hg). + ), ethylmercury ((CH3)2Hg), phenylmercury (PhHg) + It exists in forms such as methylmercury, among which methylmercury has a strong lipophilic ability, is more easily absorbed by organisms, and has the highest toxicity.

[0004] In the analysis and detection of arsenic and mercury, pre-concentration and enrichment are necessary due to low concentrations of the analytes and matrix interference. Common pre-enrichment methods include solvent extraction, solid-phase extraction (SPE), and supercritical fluid extraction. Solvent extraction is a traditional separation and enrichment method, but it suffers from the consumption of large amounts of high-purity reagents and emulsification issues. Supercritical fluid extraction effectively avoids the drawbacks of traditional solvent extraction for sample pre-enrichment. However, supercritical fluid extraction is mostly used for processing solid samples. It can extract and enrich methylmercury to obtain clean extracts, but this method can only process small sample volumes and cannot extract trace components from water samples. Solid-phase extraction utilizes the partitioning of the analyte between the mobile and stationary phases, retaining trace components in the sample matrix in the stationary phase, and then eluting the target ions with a suitable eluent to achieve separation and enrichment. Solid-phase extraction has a series of advantages, including high enrichment factor, low reagent consumption, high recovery rate, and simple operation. In solid-phase extraction research, adsorbents are particularly important; therefore, the synthesis of novel adsorbent materials is an important research topic.

[0005] Chinese invention application CN201510182800.4 discloses a method for enriching trace mercury in environmental water samples using dispersed solid-phase extraction. The method involves combining an adsorbent with Ag... + The adsorbent was added to a water sample for adsorption. The adsorbent was extracted by filtration in a vacuum filtration device consisting of an all-glass replaceable membrane filter and a vacuum pump. Continuous filtration followed, with eluent (a mixture of L-cysteine ​​and acetonitrile in water) eluted onto the filter membrane surface. The adsorbent containing the analyte was transferred along with the filter membrane to a needle-type replaceable membrane filter. The eluent was added to the needle-type replaceable membrane filter using a pipette, and then ejected from the filter using a syringe. This invention only enriched mercury ions in the water sample; it could not enrich or separate other metal ions.

[0006] Chinese invention patent CN201510416734.2 discloses a method for determining trace arsenic in rice using solid-phase extraction atomic fluorescence spectrometry (SPEF). This method utilizes chromatographic silica gel modified with pyrrolidine dithiocarbamate (APDC) as an adsorbent to separate and enrich arsenic, and thiourea ascorbic acid as a reducing agent and masking agent to establish an APDC SPEF method for determining arsenic in rice. The fluorescence intensity of arsenic in rice is measured using this method, and the arsenic content is calculated from a standard curve. This invention is applicable to the determination of arsenic content in rice, but it cannot determine arsenic ions in water.

[0007] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0008] The purpose of this invention is to solve the problem that when detecting heavy metal ions, due to the low content of the analyte element and the presence of matrix interference during the analysis process, it is necessary to pre-separate and enrich the sample. This invention provides a method for preparing Fe2O3@ZnO composite material and enriching trace amounts of arsenic and mercury.

[0009] To achieve the above objectives, this invention discloses a method for preparing Fe2O3@ZnO composite materials, comprising the following steps:

[0010] S1, Weigh out zinc acetate, urea, and sodium citrate and dissolve them in 150 mL of aqueous solution;

[0011] S2, add FeCl3·6H2O to the solution in step S1 and stir with a magnetic stirrer until completely dissolved to obtain a reddish-brown homogeneous solution;

[0012] S3, the solution from step S2 is transferred to a hydrothermal synthesis reactor with a 200 mL polytetrafluoroethylene liner, and reacted at 140 °C for 16 h.

[0013] S4. Cool the product obtained in step S3 to room temperature, wash the product three times with deionized water and edible alcohol respectively, and dry it in a vacuum drying oven at 70°C.

[0014] S5, collect and grind the dried Fe2O3@ZnO solid from step S4 to obtain the Fe2O3@ZnO composite material.

[0015] In step S1, the mass ratio of zinc acetate, urea, and sodium citrate is 22:75:11.

[0016] In step S2, the mass ratio of FeCl3·6H2O to zinc acetate in step S1 is 22:27.

[0017] In step S2, the zinc-to-iron ratio in the resulting solution is 2:1 to 3:1.

[0018] In step S3, the pH of the synthesis reaction is 5.

[0019] The present invention also discloses the Fe2O3@ZnO composite material prepared by the above preparation method.

[0020] This invention also discloses a method for enriching trace amounts of arsenic and mercury, comprising the following steps:

[0021] (1) Weigh the Fe2O3@ZnO composite material into a solid phase extraction column;

[0022] (2) Add deionized water to step (1) to activate the solid phase extraction column, control the flow rate by adjusting the vacuum degree, and wash the solid phase extraction column with 1 mL of deionized water.

[0023] (3) Add hydrochloric acid to the solution in step (2) for elution, and collect the eluent in a colorimetric tube;

[0024] (4) Add 0.6 mL of concentrated HCl to the colorimetric tube from step (3) and detect the concentrations of As(III) and Hg(II) by AFS.

[0025] The solid-phase extraction conditions were pH=5.

[0026] The mass of the Fe2O3@ZnO composite material in step (1) is 50 mg.

[0027] The hydrochloric acid used for elution in step (3) is 1.5 mol·L⁻¹. -1 .

[0028] In step (4), the concentrations of As(III) and Hg(II) bimetallic ions are 20 ppb and 5 ppb, respectively, and the volumes are 5 mL and 2 mL, respectively.

[0029] This invention provides a Fe2O3@ZnO composite material for enriching trace amounts of arsenic and mercury. Its porous surface allows for rapid and efficient adsorption of As(III) and Hg(II) bimetallic ions from solution. Furthermore, this composite material is used as an adsorbent in solid-phase extraction to separate As(III) and Hg(II) bimetallic ions from a pre-enriched solution. The metal ions are then eluted with a certain amount of hydrochloric acid, and the concentrations of As(III) and Hg(II) bimetallic ions after enrichment are indirectly calculated by comparing the results with a standard working curve using atomic fluorescence spectrometry.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. This invention utilizes Fe2O3@ZnO composite materials. Fe2O3 nanoparticles have strong adsorption capacity and low cost; however, they are easily oxidized and agglomerate when directly exposed to air. Nano-ZnO has good stability and is easy to prepare. By preparing a composite adsorbent of Fe2O3 and ZnO, both the antioxidant performance of Fe2O3 nanoparticles and their dispersibility can be improved. This allows for better enrichment of As(III) and Hg(II) bimetallic ions. In separation technology, solid-phase extraction has advantages such as high enrichment factor, low reagent consumption, high recovery rate, and simple operation. In detection technology, atomic fluorescence spectrometry has advantages such as high sensitivity, simple operation, and low detection limit, and can be used for the detection of arsenic and mercury content.

[0032] 2. This invention uses nano-Fe2O3@ZnO composite material as the adsorbent for solid-phase extraction enrichment of arsenic and mercury, and the synthesis method is simple. Combined with hydride generation-atomic fluorescence spectrometry detection, it achieves the enrichment of arsenic and mercury in different forms. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the solid-phase extraction process;

[0034] Figure 2 The images are scanning electron microscope (SEM) images of each material at low and high magnification. a is Fe2O3 at low magnification, b is Fe2O3 at high magnification, c is ZnO at low magnification, d is ZnO at high magnification, e is Fe2O3@ZnO at low magnification, and f is Fe2O3@ZnO at high magnification.

[0035] Figure 3 Infrared spectra of ZnO, Fe2O3, and Fe2O3@ZnO;

[0036] Figure 4 Infrared spectra of Fe2O3@ZnO synthesized under different zinc-iron ratios;

[0037] Figure 5Infrared spectra of Fe2O3@ZnO synthesized with different sodium citrate contents;

[0038] Figure 6 XRD patterns of Fe2O3, ZnO, and Fe2O3@ZnO;

[0039] Figure 7 Different types of composite materials prepared in Example 4 are effective against As. 3+ (A), Hg 2+ (B) The effect of enrichment;

[0040] Figure 8 The Fe2O3@ZnO composite materials with different pH values ​​prepared in Example 5 are effective against As 3+ (A), Hg 2+ (B) The effect of enrichment;

[0041] Figure 9 The Fe2O3@ZnO composite materials with different sodium citrate contents prepared in Example 6 are effective against As 3+ (A), Hg 2+ (B) The effect of enrichment;

[0042] Figure 10 The Fe2O3@ZnO composite materials with different zinc-to-iron ratios prepared in Example 7 are used to study the effects of As... 3+ (A), Hg 2+ (B) The effect of enrichment;

[0043] Figure 11 The Fe2O3@ZnO composite materials prepared in Example 8 with different reaction times for As 3+ (A), Hg 2+ (B) The effect of enrichment;

[0044] Figure 12 The Fe2O3@ZnO composite materials prepared in Example 9 at different reaction temperatures for As 3+ (A), Hg 2+ (B) The effect of enrichment; Detailed Implementation

[0045] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0046] The relevant characterization methods for the embodiments are as follows:

[0047] The microstructure of the material was observed using a scanning electron microscope (S4800), analyzed using a Fourier transform infrared spectrometer (VEC-TOR22), analyzed using X-ray diffraction (Ultima IV), and finally the enrichment properties of the material were analyzed.

[0048] Example 1

[0049] 1) Accurately weigh zinc acetate, urea, and sodium citrate and dissolve them in an aqueous solution;

[0050] 2) Add FeCl3·6H2O to the solution in step 1) and stir with a magnetic stirrer until completely dissolved to obtain a reddish-brown homogeneous solution;

[0051] 3) Pour the solution from step 2) into a hydrothermal synthesis reactor lined with polytetrafluoroethylene and react at 140°C for 16 hours;

[0052] 4) After the obtained product is cooled to room temperature, it is washed three times with deionized water and edible alcohol respectively, and then dried in a vacuum drying oven at 70℃.

[0053] 5) Collect and grind the dried Fe2O3@ZnO solid for later use;

[0054] The material was subjected to electron microscopy to observe its surface morphology. The results are as follows: Figure 2 As shown.

[0055] As can be seen from the scanning electron microscope image, the synthesized Fe2O3 particles have poor dispersibility. Figure 2 (b) is a high-magnification scanning electron microscope image, which shows that Fe2O3 is in the form of uniformly sized spheres. Figure 2 (c) is a scanning electron microscope image of ZnO at low magnification. As can be seen from the image, ZnO is a rough-surfaced spherical shape with a soft texture. Figure 2 (d) is a high-magnification scanning electron microscope image of ZnO. It can be seen more clearly that the diameter is approximately 15 μm and there are small gaps on the surface. Figure 2 (e) is an electron microscope image of Fe2O3-modified ZnO at low magnification. It can be seen that the surface of the synthesized composite material is loose and porous with large channels. Figure 2 (f) is a high-magnification scanning electron microscope image, which shows that the synthesized nanoparticles exhibit severe agglomeration and have an uneven surface.

[0056] Example 2

[0057] Infrared spectroscopy was performed on ZnO, Fe2O3, Fe2O3@ZnO, Fe2O3@ZnO synthesized with different zinc-iron ratios (3:1, 2:1, 1:1, 1:2), and Fe2O3@ZnO synthesized with different sodium citrate contents. The results are as follows: Figure 3 , Figure 4 and Figure 5 As shown.

[0058] As shown by the infrared spectrum, Figure 3 1623cm-1 and 3422cm -1 The peaks at the Fe2O3 surface hydroxyl groups are characteristic peaks of bending and stretching vibrations. Figure 4 These are the FT-IR absorption spectra of Fe2O3@ZnO synthesized under different zinc-to-iron ratios, with the 560 cm⁻¹ value being the most significant. -1 The strong peak at 400 cm⁻¹ is the stretching vibration peak of Fe-O. -1 The presence of a Zn-O peak indicates successful synthesis of Fe2O3@ZnO. The intensity of the Fe-O peak gradually decreases with increasing zinc-to-iron ratio. Figure 5 These are the FT-IR absorption spectra of Fe2O3@ZnO synthesized with different sodium citrate contents, where 3423 cm⁻¹ is the most significant. -1 and 1074cm -1 The peak at 1400 cm⁻¹ is the stretching vibration peak of the hydroxyl group. -1 and 1620cm -1 The peaks at the positions are the symmetric stretching vibration peak and the asymmetric stretching vibration peak of the carbonyl group of the carboxylate, respectively. As the sodium citrate content increases, the intensity of the characteristic absorption peaks of hydroxyl and carboxylate gradually increases, indicating that the content of hydroxyl and carboxyl groups on the surface of the composite material gradually increases.

[0059] Example 3

[0060] X-ray diffraction analysis was performed on the materials Fe2O3, Fe2O3@ZnO, and ZnO, and the results are as follows: Figure 6 As shown.

[0061] The XDR image shows that Fe2O3 exhibits diffraction peaks with 2θ values ​​of 24.18°, 33.2°, 35.72°, 41.02°, 49.54°, 53.98°, 62.48°, and 63.98°, which correspond to the diffraction peaks of Fe2O3 in the standard card (JCPDS No. 33-0664), proving that Fe2O3 was successfully synthesized. In the figure, 2θ = 31.38°, 34.66°, 36.32°, 47.68°, 55.62°, 62.94°, 67.22°, and 69.10° correspond to the (100), (002), (101), (102), (110), (103), (112), and (201) crystal planes of ZnO (JCPDS No. 79-0206), respectively. In the figure, the diffraction peaks at 2θ of 30.06°, 35.36°, 42.88°, and 53.16° belong to the (220), (311), (400), and (422) crystal planes of Fe2O3. The diffraction peaks at 56.88° and 62.24° are diffraction peaks of the (110) and (103) crystal planes of ZnO, indicating that ZnO was successfully loaded onto Fe2O3.

[0062] Example 4

[0063] The enrichment effects of six materials—Fe2O3@ZnO, Sn3O4@ZnO, Al2O3@ZnO, MnO2@ZnO, ZnO, and ZrO2@ZnO—on trivalent As (A) and divalent Hg (B) were compared. The results are as follows: Figure 7 As shown. (The synthesis methods of Sn3O4@ZnO, Al2O3@ZnO, MnO2@ZnO, ZnO, and ZrO2@ZnO are all the same as those of Fe2O3@ZnO, except that Fe2O3@ZnO is replaced with Sn3O4, Al2O3, MnO2, and ZrO2.) The curves show that Fe2O3@ZnO material has the best enrichment effect on trivalent As (A) and divalent Hg (B).

[0064] The specific steps of the method for enriching trace amounts of arsenic and mercury are as follows: Weigh 50 mg of the above composite material into a solid-phase extraction column. First, add deionized water to activate the solid-phase extraction column. Control the flow rate by adjusting the vacuum level during sample loading. Wash the solid-phase extraction column with 1 mL of deionized water. After sample loading, add 1.5 mol·L⁻¹ water. -1 The solution was eluted with hydrochloric acid, and the eluent was collected in a colorimetric tube. Finally, 0.6 mL of concentrated HCl was added to the colorimetric tube, and the concentrations of As(III) and Hg(II) were detected by AFS.

[0065] Example 5

[0066] The pH of the Fe2O3@ZnO synthesis reaction was varied (pH 3, 5, and 7; sodium citrate content 6 mmol / L; zinc-to-iron ratio 3:1; reaction time 16 h; reaction temperature 140 °C) to investigate the effect of vacuum degree on the recovery rate. The results are as follows: Figure 8 As shown.

[0067] The results showed that the recovery rate increased as the vacuum level decreased. With increasing synthesis pH, the recovery rate of the adsorbent for Hg(II) increased, while the recovery rate for As(III) decreased. The solid-phase extraction adsorbent synthesized at pH 7 showed the best enrichment effect for Hg(II), with a maximum recovery rate of 97.10%. However, at pH 7, the adsorbent had almost no effect on the enrichment of As(III). This may be because as the synthesis pH increased, the positive charge of the adsorbent material decreased, increasing the electrostatic attraction to Hg(II) in its positively charged cation form, while decreasing the electrostatic attraction to As(III) in its negatively charged anionic form ionized in water.

[0068] Example 6

[0069] The effect of varying the amount of sodium citrate in the Fe2O3@ZnO reaction (sodium citrate content of 1.5 mmol, 3 mmol, 6 mmol, and 15 mmol, with a synthesis reaction pH of 5, a zinc-to-iron ratio of 3:1, a reaction time of 16 h, and a reaction temperature of 140 °C) on the enrichment properties of the composite material was investigated. The results are as follows: Figure 9 As shown.

[0070] The results showed that the composite material obtained with a sodium citrate content of 6 mmol / L exhibited the best enrichment effect for As(III) (46.53%), while the recovery rate of Hg(II) reached 95.66%. Sodium citrate possesses excellent complexing and dispersing abilities for metal ions, acting as a ligand to guide crystal growth. With increasing sodium citrate content, the enrichment effect for As(III) and Hg(II) showed a trend of first increasing and then decreasing. This may be because, on the one hand, increasing the sodium citrate content increases the content of carboxyl groups that can complex with metal ions, promoting crystal growth and improving adsorption performance; on the other hand, excessively high sodium citrate content leads to a decrease in the specific surface area and total pore volume of the adsorbent, which is detrimental to adsorption. Therefore, considering all factors, a sodium citrate content of 6 mmol / L was selected as the optimal content for synthesis.

[0071] Example 7

[0072] The effect of vacuum degree on the enrichment effect of the adsorbent was investigated by changing the zinc-iron ratio (3:1, 2:1, 1:1, 1:2, pH=5, sodium citrate content 6 mmol / L, reaction time 16 h, and reaction temperature 140℃). The results are as follows: Figure 10 As shown.

[0073] The results showed that the recovery rate increased with decreasing vacuum level. Vacuum level affects the recovery rate by influencing the sample flow rate. The sample injection flow rate has a significant impact on enrichment performance; a faster flow rate shortens the enrichment time, but excessively fast flow rates reduce enrichment efficiency. Lower vacuum levels result in slower sample flow rates, allowing for more thorough contact between the sample solution and the adsorbent, thus improving enrichment performance. At a Zn-Fe ratio of 3:1, the composite material achieved the highest recovery rate of As(III) at 64.97%, demonstrating the best enrichment effect. Furthermore, at a Zn-Fe ratio of 3:1, the recovery rate of Hg(II) reached over 95%. Therefore, considering all factors, a Zn-Fe ratio of 3:1 was selected as the optimal ratio for synthesis.

[0074] Example 8

[0075] The reaction time of Fe2O3@ZnO was varied (reaction times were 10h, 12h, 14h, and 16h; the synthesis reaction pH was 5; the sodium citrate content was 6 mmol / L; the zinc-to-iron ratio was 3:1; and the reaction temperature was 140℃) to investigate the effect of the composite material on the enrichment performance of As(III) and Hg(II). The results are as follows: Figure 11 As shown.

[0076] The results showed that the composite material achieved the highest recovery rates of As(III) and Hg(II) (88.63% and 98.22%, respectively) at a reaction time of 16 h. Therefore, 16 h was selected as the optimal reaction time. The recovery rate increased with increasing reaction time, which may be due to the decrease in the size of the composite material as the reaction time increases, thereby increasing the specific surface area of ​​the synthesized material, which is beneficial for the enrichment of As(III) and Hg(II).

[0077] Example 9

[0078] The reaction temperature of Fe2O3@ZnO was varied (reaction temperatures were 140℃, 160℃, 180℃, and 200℃; the synthesis reaction pH was 5; the sodium citrate content was 6 mmol / L; the zinc-to-iron ratio was 3:1; and the reaction time was 16 h). The effect of the composite material on the enrichment performance of As(III) and Hg(II) was investigated. The results are as follows: Figure 12 As shown.

[0079] The results showed that the composite material achieved the highest recovery rates of As(III) and Hg(II), reaching 97.99% and 98.43%, respectively, at a reaction temperature of 140℃. Therefore, 140℃ was selected as the optimal reaction temperature. The recovery rate decreased with increasing temperature, which may be due to the increased solute convection and nucleation rate of crystals, leading to an increase in the diameter and decrease in the specific surface area of ​​the synthesized composite material.

[0080] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A method of enriching trace arsenic mercury, characterized by, The method comprises the following steps: (1) weighing Fe2O3@ZnO composite material in a solid phase extraction column; (2) adding deionized water to activate the solid phase extraction column in step (1), controlling the flow rate by adjusting the vacuum degree, and washing the solid phase extraction column with 1 mL of deionized water; (3) adding hydrochloric acid to step (2) for elution, and collecting the eluate in a colorimetric tube; (4) adding 0.6 mL of concentrated HCl to the colorimetric tube in step (3), and detecting the concentrations of As(III) and Hg(II) by AFS; The preparation method of the Fe2O3@ZnO composite material in step (1) comprises the following steps: S1, weighing zinc acetate, urea and sodium citrate and dissolving them in an aqueous solution; S2, adding FeCl3·6H2O to the solution in step S1 to the magnetic stirrer and stirring until completely dissolved to obtain a red-brown uniform solution; S3, transferring the solution in step S2 to a hydrothermal synthesis reaction kettle containing a polytetrafluoroethylene liner for reaction, and reacting at 140℃ for 16 h; S4, cooling the product obtained in step S3 to room temperature, washing the product with deionized water and edible alcohol three times respectively, and drying in a 70℃ vacuum drying box; S5, collecting and grinding the dried Fe2O3@ZnO solid in step S4 to obtain Fe2O3@ZnO composite material.

2. A method of enriching trace arsenic mercury as claimed in claim 1 wherein, In step S1, the mass ratio of zinc acetate, urea and sodium citrate is 22:75:

11.

3. A method of enriching trace arsenic mercury as claimed in claim 1 wherein, In step S2, the mass ratio of FeCl3·6H2O to zinc acetate in step S1 is 22:

27.

4. The method of claim 1, wherein the method is for enriching trace amounts of arsenic mercury. In step S2, the zinc-iron ratio in the obtained solution is 2:1-3:

1.

5. The method for enriching trace amounts of arsenic and mercury as described in claim 1, characterized in that, In step S3, the pH of the synthesis reaction is 5.

6. A method of concentrating trace arsine mercury as claimed in claim 1, wherein, The mass of the Fe2O3@ZnO composite material in step (1) is 50 mg.

7. A method of concentrating trace arsine mercury as claimed in claim 1, wherein, The hydrochloric acid used in the step (3) is 1.5 mol·L -1 .

8. The method of claim 1, wherein the method is for enriching trace amounts of arsine mercury. In step (4), the concentrations of As(III) and Hg(II) bimetallic ions are 20 ppb and 5 ppb respectively, and the volumes are 5 mL and 2 mL respectively.

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