A goethite-supported anion exchange resin, its preparation method, and its application in passive monitoring of arsenic pollution in water bodies.

Abstract

This invention discloses a goethite-loaded anion exchange resin, its preparation method, and its application in passive monitoring of arsenic pollution in water bodies. A commercially available anion exchange resin is modified and then heat-treated to enhance its arsenic adsorption capacity and stability. The response of the arsenic adsorption capacity of the goethite-loaded anion exchange resin to the environmental arsenic concentration under flowing conditions is obtained using a flow permeation device. The goethite-loaded anion exchange resin is then used as the adsorption medium and placed into the water body to be monitored. After a period of time, it is recovered, and the accumulated arsenic is desorbed and detected, thus obtaining the time-weighted average concentration of arsenic in the water body over the monitoring period. Compared to the instantaneous concentration obtained from a single manual water sample collection, this invention better reflects the overall pollution status over the monitoring period. The goethite-loaded anion exchange resin of this invention can be recycled after recovery and arsenic desorption. After five cycles, the arsenic adsorption rate does not change significantly, and the adsorption capacity still reaches more than 95% of the original, effectively reducing the operating cost.

Description

Technical Field

[0001] This invention relates to the field of arsenic content monitoring technology in polluted water bodies, specifically to a goethite-supported anion exchange resin, its preparation method, and its application in passive monitoring of arsenic pollution in water bodies. Background Technology

[0002] Arsenic (As) is a toxic metallic element. Long-term exposure to arsenic can exacerbate health problems such as diabetes and cardiovascular disease, and cause cancers such as skin cancer and bladder cancer. Arsenic is used in industrial and agricultural fields such as herbicides, pesticides, semiconductors, and alloy production, and is widely present in soil and water bodies. In addition, with the mining of arsenic-containing minerals, the release of arsenic during coal combustion, and the existence of high-arsenic groundwater in some areas, arsenic has become one of the most common and concerning pollutants.

[0003] Arsenic exists primarily in inorganic forms in environmental water bodies, and inorganic arsenic is generally considered more toxic than organic arsenic. Various methods exist for monitoring pollutants in water, including arsenate. Common methods include on-site determination of water samples using colorimetric reagent kits based on the Guizet method, molybdenum blue method, or fluorescence method, but these on-site methods have relatively low sensitivity and accuracy. Manually collecting water samples and bringing them back to the laboratory for detection using methods such as inductively coupled plasma mass spectrometry, hydride generation atomic absorption spectrometry, and graphite furnace atomic absorption spectrometry can achieve high sensitivity. However, the effectiveness of this monitoring is highly dependent on the sampling frequency, often facing manpower shortages in large-scale applications. Furthermore, the resulting discrete monitoring data may miss specific pollution events, such as intermittent industrial pollutant emissions or arsenic release from farmland soil due to heavy rainfall. Using on-site online monitoring devices can avoid the above-mentioned drawbacks, such as the C310 total arsenic water quality online monitor developed by ZTE Instruments Co., Ltd. (Shenzhen) and the PhotoTek 6000 total arsenic water quality automatic online analyzer developed by Langshi Scientific Instruments Co., Ltd. (Shenzhen). However, the required equipment cost and maintenance cost are relatively high, and they are more suitable for real-time monitoring of point pollution sources such as industrial wastewater discharge outlets, but difficult to apply in scenarios that require large-scale monitoring, such as water source protection and agricultural water environment.

[0004] Because arsenic concentrations in natural water bodies are typically low, often at the microgram per liter level, the accuracy of monitoring methods is crucial. While existing technologies offer numerous methods for arsenic detection, their accuracy is relatively low. For example, on-site monitoring using colorimetric reagent kits has relatively low sensitivity and is highly subjective, while high-precision laboratory analysis relies on frequent manual sampling and transportation. Therefore, a method that is relatively inexpensive in terms of both manpower and equipment costs and is suitable for monitoring arsenic levels in large-scale natural water bodies is lacking. Summary of the Invention

[0005] Arsenic in oxygenated surface waters primarily exists as arsenate ions. Anion exchange resins can adsorb arsenate ions in water, but due to their non-specific adsorption principle based on ion exchange reactions, the fixation effect on arsenate ions is difficult to guarantee under the interference of other anions in the environment. To address the shortcomings of existing technologies, this invention aims to provide a goethite-supported anion exchange resin, its preparation method, and its application in passive monitoring of arsenic pollution in water bodies. The exchange resin used is based on commercially available anion exchange resin, modified to be inexpensive and readily available. The synthesized goethite-supported anion exchange resin can be recycled after recovery and arsenic desorption, meeting the needs of arsenic enrichment media in water bodies and showing promising application prospects.

[0006] To overcome the shortcomings of the existing technology, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a goethite-supported anion exchange resin includes the following steps:

[0008] Step 1: Weigh 30g of commercial anion exchange resin as the substrate material, add it to a 500mL polypropylene plastic bottle, add 250mL of 1mol / L nitric acid, and shake to incubate.

[0009] Step 2: After the shaking culture is completed, pour out the nitric acid solution, add 250 ml of deionized water, shake for 10 minutes, pour out the solution, wash twice with deionized water, add 100 mL of 0.5 mol / L ferric nitrate, shake evenly, add 100 mL of 4 mol / L sodium hydroxide, and make up to a total volume of 500 mL with deionized water. Heat the solution to complete the loading and conversion of iron ions on the resin.

[0010] Step 3: Wash the composite resin twice with deionized water, then add 250 mL of 1 mol / L sodium chloride, shake to react and exchange hydroxide ions on the resin surface, then wash with deionized water until neutral to obtain goethite-supported anion exchange resin.

[0011] As an improvement, the basic skeleton of the anion exchange resin in step 1 is polypropylene, and the functional group is quaternary ammonium.

[0012] As an improvement, the shaking incubation speed in steps 1 and 2 is 100 rpm, and the shaking time is 1 hour.

[0013] As an improvement, the heating temperature in step 2 is 70°C, and the heating time is 60 hours.

[0014] As an improvement, the shaking incubation speed in step 3 is 100 rpm, and the shaking time is 1 hour.

[0015] The composite resin material prepared by the above preparation method is a reddish-brown spherical particle with a particle size of 0.65-0.8 mm; the iron content in the goethite-supported anion exchange resin is 19.8 mg / g, and it is in the form of goethite, which is stably loaded on the resin.

[0016] Application of the goethite-supported anion exchange resin prepared by the above method in passive monitoring of arsenic pollution in water bodies.

[0017] The application of the above-mentioned goethite-supported anion exchange resin in passive monitoring of arsenic pollution in water includes the following steps:

[0018] Step 1: A flow permeation apparatus was used to confirm the relationship between the adsorption capacity of the goethite-supported anion exchange resin for arsenate and the response of arsenate in the environment.

[0019] Sodium arsenate was dissolved in 0.01 mol / L sodium chloride to prepare a 0.2 mg / L arsenic stock solution. 2 g of goethite-supported anion exchange resin was weighed and placed in the reaction chamber of a flow permeation apparatus. A peristaltic pump was turned on to allow the arsenic solution to flow through the reaction chamber at a uniform rate. After running for 1-12 hours, the goethite-supported anion exchange resin was recovered into a 50 mL centrifuge tube. 20 mL of a mixed solution of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate was added, and the mixture was shaken at 50 rpm for 16 hours to desorb and extract the arsenic adsorbed by the goethite-supported anion exchange resin. The solution was then filtered through a 0.45 μM filter membrane, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS) and converted into the amount of arsenic adsorbed. The response coefficient of the goethite-supported anion exchange resin to arsenate was then obtained through linear fitting.

[0020] Step 2: 2g of goethite-loaded anion exchange resin was packed into a 100-mesh polyester fiber mesh bag, sealed, and placed into the water body to be monitored. The deployment time was determined according to the actual situation. The adsorption bag containing the goethite-loaded anion exchange resin was periodically removed and replaced. The recovered goethite-loaded anion exchange resin was washed with deionized water, transferred to a 50mL centrifuge tube, and then desorbed and extracted for arsenic using a mixed solution of 20mL of 0.5mol / L sodium hydroxide and 0.5mol / L sodium sulfate. Afterward, the solution was filtered through a 0.45μM filter membrane, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry. The time-weighted average concentration of arsenic in the water body during the monitoring period was calculated by converting the response coefficient.

[0021] As an improvement, the goethite-supported anion exchange resin exhibits a stable adsorption rate for arsenic during passive monitoring of arsenic pollution in water bodies. After five adsorption-desorption cycles, the adsorption capacity still reaches more than 95% of the initial adsorption capacity.

[0022] Beneficial effects

[0023] Compared with existing technologies, the goethite-supported anion exchange resin and its preparation method disclosed in this invention, along with its application in passive monitoring of arsenic pollution in water bodies, have the following advantages:

[0024] 1. After modification and heat aging treatment of commercial anion exchange resins, the iron loading in the goethite-loaded anion exchange resin is firm, and the arsenic adsorption performance is stable. After 5 adsorption and desorption cycles, the adsorption capacity of the composite resin for arsenic can still reach more than 95% of the original value, and the adsorption rate remains stable.

[0025] 2. The monitoring method proposed in this invention obtains the response relationship between the arsenic adsorption capacity of goethite-supported anion exchange resin and the environmental arsenic concentration through indoor experiments. Then, the goethite-supported anion exchange resin is used as the adsorption medium and placed in the water body to be monitored. After a period of time, it is recovered, and the arsenic enriched in the material is desorbed and detected, thereby obtaining the time-weighted average concentration of arsenic in the water body during the monitoring period. Compared with the instantaneous concentration obtained from a single manual water sample collection, this method better reflects the overall pollution status during the monitoring period.

[0026] 3. Due to the enrichment of arsenic in the adsorption medium, this method also has good monitoring effects on natural water bodies with low arsenic concentrations. Specifically, when using inductively coupled plasma mass spectrometry (ICP-MS) with a detection limit of 0.2 μg / L to determine the arsenic desorbed from the composite resin, the corresponding arsenic concentration in the water body was 0.021 μg / L with a monitoring period of 7 days, effectively extending the detection limit of arsenic in water bodies.

[0027] 4. The materials required for the monitoring method of the present invention are inexpensive and readily available, and the goethite-loaded anion exchange resin can be recycled and reused after recovery and arsenic desorption, which is green and environmentally friendly and further reduces the cost of use in practical applications. Attached Figure Description

[0028] Figure 1 X-ray diffraction pattern of the goethite-supported anion exchange resin HD730 prepared in Example 1;

[0029] Figure 2 (a) shows the adsorption kinetics curves of arsenic by different anion exchange resins;

[0030] Figure 2 (b) shows the pseudo-second-order kinetic model fitting curves for different anion exchange resins, where k is the adsorption rate constant obtained from the fitting.

[0031] Figure 3 (a) is the isothermal adsorption curves of arsenic by different anion exchange resins;

[0032] Figure 3 (b) are the Langmuir fitting curves for different anion exchange resins, where Q is the arsenic adsorption capacity obtained from the fitting.

[0033] Figure 4 The iron content (a), arsenic adsorption rate constant (b), and arsenic adsorption capacity (c) of the goethite-supported anion exchange resin prepared in Example 1 after multiple adsorption-elution cycles are shown.

[0034] Figure 5 This is a schematic diagram of the flow permeation device used in the present invention, wherein 1-Marsh flask, 2-reaction chamber, 3-peristaltic pump;

[0035] Figure 6 In the experiment to obtain the response coefficient, the cumulative adsorption amount of arsenic in the goethite-supported anion exchange resin prepared in Example 1 was measured at different running times.

[0036] Figure 7 To verify the effectiveness of the water arsenic monitoring method;

[0037] Figure 8 The iron content (a), arsenic adsorption rate constant (b), and arsenic adsorption capacity (c) of the iron-supported anion exchange resin prepared for Comparative Example 1 after multiple adsorption-elution cycles. Detailed Implementation

[0038] Example 1: A method for preparing a goethite-supported anion exchange resin

[0039] A method for preparing goethite-supported anion exchange resin, using commercially available anion exchange resin (D730, Hydrolite) TM (Zhejiang) was used as the substrate material. Specifically, 30g of commercial anion exchange resin was weighed into a 500mL polypropylene plastic bottle, 250mL of 1mol / L nitric acid was added, and the mixture was shaken at 100rpm for 1 hour in a shaking incubator. After washing twice with deionized water, 100mL of 0.5mol / L ferric nitrate was added, and the mixture was shaken at 100rpm for 1 hour. Then, 100mL of 4mol / L sodium hydroxide was added, and deionized water was added to a total volume of 500mL. The mixture was then placed in a 70℃ oven and heated for 60 hours to complete the loading and conversion of iron ions on the resin. Finally, the composite resin was washed twice with deionized water, and then 250mL of 1mol / L sodium chloride was added, and the mixture was shaken at 100rpm for 1 hour to exchange hydroxide ions on the resin surface. After washing again with deionized water, goethite-supported anion exchange resin HD730 was obtained.

[0040] To characterize the iron loading of the synthesized resin, 0.1 g of HD730 was weighed and added to 100 mL of a mixed solution of 5% hydroxylamine hydrochloride and 5 mol / L hydrochloric acid. The solution was ultrasonically heated in a water bath at 40 kHz and 120 W for 10 minutes, then shaken at 100 rpm for 24 hours. The supernatant was then filtered through a 0.45 μm filter, and the iron concentration in the solution was determined using an inductively coupled plasma mass spectrometer (Agilent 7900, USA) and converted to the iron content in HD730. The result was 19.8 mg / g. Furthermore, X-ray diffraction (XRD) analysis was used to analyze the morphology of the loaded iron. The spectrum showed that the peak shape of the material perfectly matched the characteristic peaks of goethite, proving that all the iron loaded in the composite resin HD730 prepared in this embodiment was in the goethite morphology. Figure 1 Compared to other forms such as amorphous arsenic, goethite is more stable, which helps to maintain constant adsorption characteristics for arsenic (as shown in the adsorption-desorption cycle test below), thus meeting the requirements for use as an adsorption medium for arsenic monitoring in water bodies.

[0041] The kinetics of arsenic adsorption on goethite-supported anion exchange resin were studied using batch experiments. 0.1 g of resins D730 and HD730 were weighed into 50 mL centrifuge tubes, and 30 mL of 10 mg / L sodium arsenate solution was added. The tubes were incubated at 25 °C with shaking at 100 rpm. Samples were taken at different time points and filtered through a 0.45 μm filter. The arsenic content in the solution was determined using inductively coupled plasma mass spectrometry (ICP-MS) (Agilent 7900, USA) according to the national standard HJ700-2014. The results are as follows: Figure 2 As shown in the figure, the solid line represents HD730 and the dashed line represents D730. The figure shows that the adsorption of arsenic by both resins conforms to a pseudo-second-order kinetic model. The adsorption rate of arsenic by the resin after loading with goethite is significantly improved, with a rate constant reaching 0.04 g / mg / min.

[0042] The arsenic adsorption capacity of goethite-supported anion exchange resin was determined using isothermal adsorption experiments. 0.1 g of resins D730 and HD730 were weighed into 50 mL centrifuge tubes, and 30 mL of sodium arsenate solution with concentrations ranging from 3-50 mg / L was added to each. The tubes were incubated at 25 °C with shaking at 100 rpm for 1 hour. The supernatant was then filtered through a 0.45 μm filter, and the arsenic content in the solution was measured. The arsenic adsorption capacity was fitted to the arsenic equilibrium concentration, and the results are shown below. Figure 3 As shown in the diagram, the solid line represents HD730, and the dashed line represents D730. From Figure 3 (a) and Figure 3As can be seen from (b), the adsorption of arsenate by the goethite-supported anion exchange resin HD730 prepared in this invention is significantly higher than that by D730. The adsorption curve conforms to the Langmuir model. Under the condition of initial arsenic concentration of 3-50 mg / L, the maximum adsorption capacity is 11.2 mg / g, which meets the requirements as an adsorption medium for arsenic monitoring in water.

[0043] Arsenic desorption was performed by adding 20 mL of a mixed solution of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate to the goethite-supported anion exchange resin after the isothermal adsorption test. After shaking at 100 rpm for 24 hours, the resin was washed with deionized water until neutral and then shaken at 100 rpm for 48 hours. The iron content in the resin was then determined according to the above method, and adsorption kinetics and isothermal adsorption tests were performed again. Arsenic desorption was then performed again. After five cycles, the iron content and arsenic adsorption capacity of each resin were as follows: Figure 4 As shown in the figure, the solid line represents HD730 and the dashed line represents D730. It can be seen that after 5 adsorption-elution cycles, the iron content of the composite resin HD730 still reaches 94.7% of the original value, the adsorption rate constant does not change significantly, and the arsenic adsorption capacity still reaches 95.6% of the original value.

[0044] Example 2: Obtaining the Response Coefficient

[0045] To achieve effective monitoring of the target analyte, the amount of analyte adsorbed by the adsorption medium must be linearly related to the exposure level (proportional to concentration and time). This can be achieved by employing methods such as... Figure 5 The flow permeation apparatus shown was used to confirm the relationship between the adsorption capacity of goethite-supported anion exchange resin HD730 for arsenate and the response of arsenate in the environment. The flow permeation apparatus consists of a Marvin flask 1, a reaction chamber 2, and a peristaltic pump 3. The Marvin flask 1 is connected to the upper part of the reaction chamber 2 by a 5mm hose, and the lower part of the reaction chamber 2 is connected to the peristaltic pump 3 by a 5mm hose. After passing through the peristaltic pump, the sample solution is collected in a plastic bottle.

[0046] Specifically, sodium arsenate was dissolved in 0.01 mol / L sodium chloride to prepare a 0.2 mg / L arsenic stock solution, which was then poured into a Marvin flask. 2 g of goethite-supported anion exchange resin HD730 was weighed and placed in the reaction chamber of a flow permeation apparatus. A peristaltic pump was turned on to allow the arsenic solution to flow through the reaction chamber at a uniform rate. After running for different times (1-12 hours), the resin was recovered into a 50 mL centrifuge tube. 20 mL of a mixed solution of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate was added, and the mixture was shaken at 50 rpm for 16 hours to desorb and extract the arsenic adsorbed by the resin (by preparing a resin with a known arsenic adsorption capacity, performing desorption and extraction, and calculating the extraction rate, the extraction rate of the leaching method of this invention was 99.2%). The solution was then filtered through a 0.45 μM filter membrane, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS) and converted to the arsenic adsorption capacity of the goethite-supported anion exchange resin HD730.

[0047] Fit the device operating time with the arsenic adsorption amount (e.g.) Figure 6 The two are confirmed to have a linear relationship within the test range, described by the following formula:

[0048] m t =R s ·c·t

[0049] The response coefficient Rs obtained through the above linear fitting is 0.0023 (hours / liter). Where t is the running time, m... t denoted as arsenic adsorption amount, and c is the concentration of arsenic in the solution.

[0050] Example 3: Verification of the passive monitoring effect of arsenic in water based on goethite-supported anion exchange resin

[0051] Two g of goethite-loaded anion exchange resin HD730 was packed into a 100-mesh polyester fiber mesh bag, sealed, and then placed into the water body to be monitored. The deployment time was determined according to the actual situation, and the bag was periodically removed and replaced with a new HD730 adsorption bag.

[0052] The recovered goethite-supported anion exchange resin HD730 was washed with deionized water and transferred to a 50 mL centrifuge tube. Arsenic was then desorbed and extracted using a mixed solution of 20 mL of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate. The solution was then filtered through a 0.45 μM filter, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS) according to the national standard HJ700-2014. The time-weighted average concentration C of arsenic in the water during the monitoring period was calculated using the following formula. TWA :

[0053]

[0054] From March to April 2024, a tributary of the Baima River in Zoucheng City, Shandong Province (35.43°N, 116.85°E) was selected to verify the monitoring effect according to the above testing method. According to the situation of this embodiment, the period was set to 7 days.

[0055] To evaluate the monitoring results of arsenic concentration in water using the above method, water samples were collected manually every 3-4 days during the monitoring period, and the arsenic concentration level was determined by inductively coupled plasma mass spectrometry.

[0056] The results are as follows Figure 7 As shown in the figure, the solid line represents the time-weighted average concentration of arsenic in the water body during different monitoring periods using HD730, and the scatter points represent the arsenic content measured by manually collected water samples during the same period. The results in the figure show that the arsenic concentrations in the water body obtained by the two monitoring methods are basically consistent, which further verifies that the novel monitoring method based on goethite-supported anion exchange resin of this invention can effectively monitor the arsenic concentration in the water body.

[0057] Furthermore, due to the enrichment of arsenic in goethite-supported anion exchange resin, this invention can reflect the overall arsenic pollution level during two sampling periods and effectively expands the detection limit for arsenic in water. Specifically, when using inductively coupled plasma mass spectrometry (ICP-MS) with a detection limit of 0.2 μg / L to determine the arsenic desorbed from the composite resin, the corresponding arsenic concentration in the water is 0.021 μg / L over a 7-day monitoring period.

[0058] Example 4: Passive monitoring of arsenic in water based on goethite-supported anion exchange resin under different ion conditions

[0059] To examine whether different ion conditions interfere with the water arsenic monitoring method of the present invention, the following tests were conducted.

[0060] Arsenic stock solutions of 0.1, 1, and 10 mg / L were prepared using sodium arsenate, and the pH of the solutions was adjusted using sodium hydroxide or hydrochloric acid, or sodium chloride, sodium nitrate, sodium carbonate, and sodium hydrogen phosphate were added at different concentrations. The prepared solutions were poured into Marvin flasks of a flow permeation apparatus. 2 g of goethite-supported anion exchange resin was weighed and placed in the reaction chamber. A peristaltic pump was turned on to allow the arsenic solution to flow through the reaction chamber at a uniform rate. After 24 hours of operation, the resin was collected into a 50 mL centrifuge tube, and 20 mL of a mixed solution of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate was added. The mixture was shaken at 50 rpm for 16 hours to desorb and extract the arsenic adsorbed by the resin. The solution was then filtered through a 0.45 μM filter, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS). The results were converted to the arsenic adsorption capacity of the resin and the corresponding arsenic concentration in the stock solution. The results are shown in Table 1.

[0061] Table 1. Arsenic concentrations measured using the monitoring method of this invention under different ion conditions.

[0062]

[0063] Note: * indicates a significant difference between the measured arsenate concentration and the result measured under interference-free ion conditions (p<0.05).

[0064] As can be seen from the table, except for the highest concentration of phosphate ions, the arsenic concentrations measured under other ion conditions were not significantly different from those measured under the interference-free ion environment.

[0065] Comparative Example 1

[0066] Except for the absence of the "heating in a 70°C oven for 60 hours" operation, the rest is the same as in Example 1.

[0067] The iron content, adsorption kinetics, and isothermal adsorption of the material prepared in Comparative Example 1 were tested after adsorption-elution cycles, following the method described in Example 1. The results are as follows: Figure 8 As shown, without heat treatment, the iron loading on the anion exchange resin is not robust, and the iron content decreases significantly after multiple adsorption-elution cycles. The adsorption rate constant and adsorption capacity for arsenic also decrease significantly, making it impossible to obtain a stable response coefficient. Therefore, it is not suitable for passive monitoring of arsenic in water.

[0068] Furthermore, the commercially available anion exchange resin D730 used in this invention costs 0.16 yuan / gram, and the prepared goethite-supported anion exchange resin costs 0.25 yuan / gram. Compared to manual single-sample detection, the additional cost required by the monitoring method proposed in this invention is less than 0.5 yuan.

Claims

1. An application of a goethite-supported anion exchange resin in passive monitoring of arsenic pollution in water bodies, characterized in that, The application Includes the following steps: A. A flow permeation apparatus was used to determine the relationship between the adsorption capacity of goethite-supported anion exchange resin for arsenate and the response of arsenate in the environment. A 0.2 mg / L arsenic stock solution was prepared by dissolving sodium arsenate in 0.01 mol / L sodium chloride. 2 g of goethite-supported anion exchange resin was weighed and placed in the reaction chamber of a flow permeation apparatus. A peristaltic pump was turned on to allow the arsenic solution to flow uniformly through the reaction chamber. After running for 1-12 hours, the goethite-supported anion exchange resin was recovered into a 50 mL centrifuge tube. A mixed solution of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate was added, and the mixture was shaken at 50 rpm for 16 hours to desorb and extract the arsenic adsorbed by the goethite-supported anion exchange resin. The solution was then filtered through a 0.45 µM filter membrane, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS) and converted into the amount of arsenic adsorbed. The response coefficient of the goethite-supported anion exchange resin to arsenate was then obtained through linear fitting. B. Use a 100-mesh polyester fiber mesh bag to fill 2 g of goethite-loaded anion exchange resin, seal it and place it in the water body to be monitored. Determine the deployment time according to the actual situation, and periodically remove and replace the adsorption bag containing goethite-loaded anion exchange resin. The recovered goethite-supported anion exchange resin was washed with deionized water and transferred to a 50 mL centrifuge tube. Arsenic was then desorbed and extracted using a mixed solution of 20 mL of 0.5 mol / L sodium hydroxide and 0.5 mol / L sodium sulfate. The solution was then filtered through a 0.45 µM filter, and the arsenic content in the filtrate was determined by inductively coupled plasma mass spectrometry (ICP-MS). The time-weighted average concentration of arsenic in the water over the monitoring period was calculated using the response coefficient. The preparation method of the goethite-supported anion exchange resin includes the following steps: Step 1: Weigh 30 g of commercial anion exchange resin as the substrate material, add it to a 500 mL polypropylene plastic bottle, add 250 mL of 1 mol / L nitric acid, and shake and incubate; the basic skeleton of the anion exchange resin is polypropylene group, and the functional group is quaternary ammonium group; Step 2: After the shaking culture is completed, pour out the nitric acid solution, add 250 ml of deionized water, shake for 10 minutes, pour out the solution, wash twice with deionized water, add 100 mL of 0.5 mol / L ferric nitrate, shake evenly, add 100 mL of 4 mol / L sodium hydroxide, and make up to a total volume of 500 mL with deionized water. Heat at 70℃ for 60 hours to complete the loading and conversion of iron ions on the resin. Step 3: Wash the composite resin twice with deionized water, then add 250 mL of 1 mol / L sodium chloride, shake to react, and exchange hydroxide ions on the resin surface. Then wash with deionized water until neutral to obtain goethite-supported anion exchange resin.

2. The application according to claim 1, characterized in that, In steps 1 and 2, the shaking incubation speed is 100 rpm and the shaking time is 1 hour.

3. The application according to claim 1, characterized in that, In step 3, the shaking incubation speed is 100 rpm and the shaking time is 1 hour.

4. The application according to claim 1, characterized in that, The composite resin material is reddish-brown spherical particles with a particle size of 0.65-0.8 mm; the iron content in the goethite-supported anion exchange resin is 19.8 mg / g, and it is in the form of goethite, which is stably loaded on the resin.

5. The application according to claim 1, characterized in that, The goethite-supported anion exchange resin exhibits a stable adsorption rate for arsenic during passive monitoring of arsenic pollution in water bodies. After five adsorption-desorption cycles, the adsorption capacity still reaches over 95% of the initial adsorption capacity.

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