Visual colorimetric sensor, preparation method thereof and application of visual colorimetric sensor in fluorine ion detection
Through the visual colorimetric sensor of the zirconium alizarin sulfonate immobilized cellulose membrane, the color change is caused by the reaction between zirconium and fluorine ions, which solves the problem of rapid and accurate detection of fluorine ion concentration in drinking water, and achieves low-cost, high selectivity and high sensitivity detection effects.
Patent Information
- Application Number
- CN202510462809.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2025-07-11
AI Technical Summary
The prior art is difficult to quickly, accurately and economically detect fluoride ion concentrations in drinking water, especially in the case of resource-constrained scenarios.
The immobilized cellulose film of zirconium alizarin sulfonate was used as a visual colorimetric sensor. The zirconium was bound to the cellulose film and the alizarin red S chromophore was introduced, and the color change was detected by the reaction of zirconium and fluorine ions.
It realizes low-cost, fast response (qualitative detection within 5 minutes) and high selectivity (strong anti-interference ability) fluoride ion detection, with a detection limit of 0.5mg/L, meeting the requirements of WHO and national standards.
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Figure CN120293959A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the cross - technical fields of new materials, sensors and ion detection, and particularly relates to a visual colorimetric sensor, a preparation method thereof, and an application in fluoride ion detection. Background Art
[0002] Groundwater in many regions of the earth contains high concentrations of fluorine elements, mostly in the form of ions (F - ). Drinking or coming into contact with such fluorine - containing water will expose people to a high - fluorine environment, which will in turn lead to serious health consequences, such as brittle bones, liver damage, endocrine disorders, abnormal calcium accumulation, and tooth discoloration. Therefore, the World Health Organization (WHO) and China have respectively strictly limited the maximum allowable content of F - in drinking water not to exceed 1.5 mg·L -1 and 1.0 mg·L -1 . How to accurately detect the concentration of F - in water has become an urgent matter.
[0003] Based on the principle of visual detection, visible colorimetric sensors have become an ideal tool for on - site rapid analysis and detection due to advantages such as easy operation and intuitive color response. Such sensors can be visually observed through color changes without relying on sophisticated instruments, and can achieve rapid identification and semi - quantitative detection of target analytes based on the transformation of characteristic colors, especially suitable for on - demand detection requirements in resource - constrained scenarios. Sensitive materials are the heart of visible colorimetric sensors. Such materials usually contain a center that has a strong interaction with the analyte and is closely coupled with the chromophore. According to different chemical environments, chemically responsive dyes can undergo color conversion in reflected or absorbed light. Zirconium (Zr) is a versatile transition metal that can effectively form stable complexes with fluoride ions and can be used as a strong interaction center for sensitive materials in visible colorimetric sensors.
[0004] The cellulose molecular chain has a regular structure and has no significant absorption in the visible light range. After dissolution and regeneration, it can be made into a film - based material with uniform, defect - free, and high optical transparency. The intermolecular hydrogen bonds and semi - crystalline structure of cellulose endow it with remarkable stability, enabling it to remain stable in various chemical environments and not easily undergo structural damage or property changes in strong acids, strong bases, water, and most organic solutions, providing an ideal substrate material for fields such as optoelectronic devices and biomedical materials. In addition, the results of scanning electron microscopy show that there are many through - pores on the surface of the cellulose membrane, providing sufficient microscopic reaction space for the interaction between the sensitive material and the analyte. Therefore, we believe that the cellulose membrane is an excellent colorimetric sensor substrate material and attempt to make it into a visual colorimetric sensor for detecting fluoride ions in water. Summary of the Invention
[0005] The present invention provides a visual colorimetric sensor based on alizarin sulfonate zirconium immobilized cellulose membrane. This sensor uses cellulose membrane as the substrate. After zirconium oxychloride octahydrate is hydrolyzed, it binds to the membrane through Zr-O bonds. Then, alizarin red S is introduced and the chromophore is immobilized on the cellulose membrane through Zr-O coordination bonds, thus obtaining the wine-red alizarin sulfonate zirconium immobilized cellulose membrane ASZ@CM. When fluoride ions exist in the sample to be detected, F - reacts with zirconium to form [ZrF6] 2- , the coordination bonds of the sensitive material are damaged, the complex disintegrates, resulting in the shedding of the chromophore, and the film shows a significant change from wine-red to colorless, thereby constructing a fluoride ion visualization detection system. The detection limit (LOD) of this sensor is as low as 0.5 mg / L, and it has extremely strong anti-interference ability, meeting the detection requirements of WHO and national standards for F - in drinking water. To achieve the above object, the technical solution adopted by the present invention is as follows:
[0006] A visual colorimetric sensor, which uses cellulose membrane as the substrate and loads alizarin sulfonate zirconium on the cellulose membrane substrate through hydrogen bonds.
[0007] Further, the content of alizarin sulfonate zirconium in the visual colorimetric sensor does not exceed 1.6 mg / g.
[0008] Further, the color of the visual colorimetric sensor will change significantly after contacting with F - from wine-red to colorless.
[0009] The present invention also provides a preparation method of the above visual colorimetric sensor, including: mixing a zirconium salt solution with a cellulose membrane for adsorption to obtain a zirconium-loaded cellulose membrane Zr@CM; under acidic conditions, mixing an alizarin sulfonate solution with the zirconium-loaded cellulose membrane Zr@CM for reaction to obtain an alizarin sulfonate zirconium-loaded cellulose membrane sensor ASZ@CM.
[0010] Further, the zirconium salt solution is specifically an aqueous solution of ZrOCl or an aqueous solution of its hydrate.
[0011] Furthermore, the concentration of the zirconium salt solution is 0.1 - 1.2 g / L.
[0012] Further, the mass ratio of the zirconium salt to the cellulose membrane during mixing is 0.6 - 1.0:4 - 6.
[0013] Further, when the zirconium salt solution is mixed with the cellulose membrane for adsorption, the temperature is 10 - 30 °C, the adsorption time is 3 - 5 h. After adsorption, solid-liquid separation is carried out and the wet membrane is washed thoroughly with water to obtain the zirconium-loaded cellulose membrane Zr@CM.
[0014] Furthermore, the preparation method of the cellulose membrane is as follows: Sodium hydroxide, urea, and short cotton lint are dissolved in water according to a mass ratio of 10-20:20-30:5-15 to form an alkaline cellulose sol. After defoaming treatment, a film is formed, and the wet film is placed in an acidic solution for curing to obtain a cellulose-based membrane.
[0015] Furthermore, the specific acidic condition is pH = 3.5-4.2. Only within this pH range can chemical chromogenic substances be generated to the maximum extent, endowing the visual colorimetric sensor with better detection effects.
[0016] Furthermore, the alizarin sulfonate solution is specifically an alizarin red S (ARS) solution with a concentration of 0.1-1.2 g / L.
[0017] Furthermore, the mass ratio of alizarin sulfonate to the zirconium-loaded cellulose membrane is 10:1-16.
[0018] The third objective of the present invention is to provide the application of the above visual colorimetric sensor in the detection of fluoride ions.
[0019] Furthermore, the detection object of the application is a solution or a solid or gas that can be formulated into a solution.
[0020] Furthermore, the detection site of the application is indoor or outdoor. This means that it can not only be used inside factories or laboratories but also be carried outdoors or to the wild for use.
[0021] Furthermore, the detection limit of the visual colorimetric sensor for fluoride ions is 0.5 mg / L.
[0022] Based on a cellulose membrane as the substrate, a zirconium salt is loaded and reacted with alizarin sulfonate to form an alizarin zirconium sulfonate-functionalized membrane ASZ@CM, and a visual colorimetric sensor for fluoride ion detection is successfully prepared. This sensor has the following advantages: (1) The preparation method is simple, easy to implement, and low in cost; (2) Fluoride ions are detected by using the significant color change during zirconium-fluorine coordination. When the sample to be tested contains fluoride ions, the color of the sensor changes from wine red to colorless, and this process realizes the visual semi-quantitative detection of fluoride ions; (3) The prepared sensor has the advantages of high selectivity (resistant to common ion interference), rapid response (qualitative detection within 5 minutes), and low detection limit (0.5 mg / L), etc. It is especially suitable for outdoor real-time detection, providing a portable and efficient solution for fluoride pollution monitoring and meeting the requirements of drinking water detection safety standards. Description of the Drawings
[0023] Figure 1 It is a graph of the selectivity test results of the ASZ@CM sensor prepared in Example 1.
[0024] Figure 2 Concentration response test result graph of the ASZ@CM sensor prepared in Example 1.
[0025] Figure 3 Time response test result graph of the ASZ@CM sensor prepared in Example 1.
[0026] Figure 4 Actual test result graph of the ASZ@CM sensor prepared in Example 1. Specific implementation manners
[0027] To enable those of ordinary skill in the art to fully understand the technical solutions and beneficial effects of the present invention, the following further description is made in conjunction with specific embodiments and the accompanying drawings. It should be emphasized that the following embodiments are only preferred embodiments of the present invention, and any simple improvements and substitutions made on this basis shall fall within the protection scope of the present invention.
[0028] Example 1
[0029] Dissolve 14 g of sodium hydroxide and 24 g of urea in 162 mL of water. After mixing evenly, freeze it to -12.5 °C, then add 8.3 g of cotton linters and stir rapidly for 10 min to obtain an alkaline cellulose sol. Since there are a large number of bubbles in the alkaline cellulose sol, it is necessary to centrifuge and defoam at a speed of 4000 rpm for 10 min. After the defoaming treatment, the alkaline cellulose sol is evenly dispersed on the glass surface by the delayed flow method, and then the glass is immersed in dilute sulfuric acid (concentration: 3 wt%) to solidify the sol into a film. After removing the film, rinse it with deionized water until neutral, and then cut it into a square with a side length of 1 cm to obtain a cellulose-based membrane.
[0030] Dissolve 0.08 g of ZrOCl2·8H2O in 200 mL of deionized water to obtain a zirconium salt solution with a concentration of 0.4 g / L. Immerse 5 g of the cellulose-based membrane in the above zirconium salt solution, and magnetically stir and adsorb the obtained mixture at room temperature for 4 h. Then, vacuum filter to remove the supernatant, and repeatedly wash the remaining wet membrane with deionized water until neutral to obtain a zirconium-loaded cellulose membrane Zr@CM.
[0031] Using deionized water as the solvent, prepare 200 mL of an alizarin red S (ARs) solution with a concentration of 0.4 g / L. Immerse the Zr@CM prepared in the previous step in the ARs solution, adjust the pH of the solution to 3.84 with dilute hydrochloric acid, and then let it stand and react at room temperature for 4 h. After the reaction, take out the wet membrane and wash it repeatedly with distilled water 3 times to obtain an alizarin sulfonic acid zircon-loaded cellulose membrane ASZ@CM sensor (the content of alizarin sulfonic acid zircon is about 0.16 mg / g). Keep the ASZ@CM sensor in distilled water for standby.
[0032] To fully understand the performance of the ASZ@CM sensor, the following tests were conducted on the samples:
[0033] 1. Selectivity test
[0034] To accurately evaluate the performance of the ASZ@CM sensor prepared by the present invention, a selectivity test was conducted by adding potential interfering substances to observe the color change of the sensor before and after detection, so as to effectively evaluate its performance and ensure its accurate and reliable execution of functions in practical applications.
[0035] When water was used as the solvent, the experiment investigated the selectivity of the ASZ@CM sensor for fluoride ions and its congeners (Cl - , Br - , I - ), other common anions (NO 3- , H2PO2 - , SCN - , IO4 - ), and cations (Cu 2+ , Fe 3+ , Ca 2+ , K + , Hg 2+ , Al 3+ , Cr 3+ ). The ion concentration of the solution to be tested was set at 100 mg / L and the volume was 20 mL. One ASZ@CM sensor was placed in each solution, and the color of the ASZ@CM sensor before and after the test was recorded with a camera. The results are shown in Figure 1 as shown in b. The G value in the three primary colors of each ASZ@CM sensor sample in Figure 1 was analyzed using ImageJ software. Taking the response color intensity to fluoride ions as the unit, the detection color response values of other ions were normalized, and finally the bar chart shown in Figure 1 was obtained. The relevant content is summarized in Table 1 as follows.
[0036] Table 1 Results of the response ability of the ASZ@CM sensor to different solutions
[0037] Sample Number Solution Type Sensor Color Change 1 <![CDATA[NaF2 at 100 mg / L]]> From Burgundy to Colorless 2 100 mg / L KCl Color Remains Unchanged 3 100 mg / L KBr Color Remains Unchanged 4 100 mg / L KI Color Remains Unchanged 5 <![CDATA[KNO3 at 100 mg / L]]> Color Remains Unchanged 6 <![CDATA[NaH2PO2 at 100 mg / L]]> Burgundy Fades 7 100 mg / L NaSCN Color Remains Unchanged 8 <![CDATA[NaIO4 at 100 mg / L]]> Burgundy Fades 9 <![CDATA[100mg / L of CuCl2]]> Color Remains Unchanged 10 100 mg / L FeCl3 Color Remains Unchanged 11 <![CDATA[CaCl2 at 100 mg / L]]> Color Remains Unchanged 12 100 mg / L KCl Color Remains Unchanged 13 100 mg / L HgCl Color Remains Unchanged 14 <![CDATA[AlNO3 at 100 mg / L]]> Color Remains Unchanged 15 100 mg / L CrCl Color Remains Unchanged
[0038] Table 1 Experimental results show that the ASZ@CM sensor prepared in Example 1 is not affected by other ions, and only undergoes a drastic and obvious color change in the presence of F - . This indicates that the ASZ@CM sensor exhibits excellent selectivity and anti-interference ability, demonstrating its potential value in practical applications.
[0039] 2. Standard solution test
[0040] The ASZ@CM sensors were immersed in 20 mL of standard aqueous NaF2 solutions with concentrations of 0 (pure water), 0.1, 0.5, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, and 35 mg / L respectively. After the reaction proceeded for 50 min, the ASZ@CM sensors were taken out and photographed with a camera. The results are as Figure 2 shown in Figure 2 Figure a. The color intensity of the ASZ@CM sensors at different concentrations was analyzed using ImageJ software. A bar chart as shown in - Figure b was plotted with the concentration as the abscissa and the color intensity as the ordinate. It was found that when the F Figure 2 concentration was in the ranges of 0 - 10 and 10 - 25 mg / L, the color intensity and the concentration showed a linear relationship. Based on this, linear graphs were plotted respectively, and the results are as
[0041] shown in Figures c and 2d. - Specifically, through the analysis of the color intensity, it was found that the G value showed a linear relationship in the ranges of 0.5 - 10 mg / L (R2 = 0.9894) and 10 - 25 mg / L (R2 = 0.9837). The reason for this phenomenon may be that at low concentrations of F Figure 2 only a small amount of ASZ can react, resulting in the dissolution of ARs from CM into the solution, and thus the color change is not obvious enough. Based on
[0042] Figure b, a standard digital colorimetric detection card was established, which can be used for the analysis of the G value in the detection of actual samples to complete quantitative analysis.
[0043] 3. Response time test - By controlling the contact time between the ASZ@CM sensor and the solution, the response rate of the ASZ@CM sensor to F Figure 3 was studied. The specific experimental process was as follows: Multiple ASZ@CM sensors of the same batch were put into 20 mL of an aqueous NaF2 solution with a concentration of 100 mg / L. Then, the ASZ@CM sensors were taken out and photographed with a camera at the 0th min, 2nd min, 5th min, 10th min, 15th min, 20th min, 30th min, 40th min, 50th min, 60th min, and 70th min. The results are as Figure 3 shown in Figure a. The color intensity at different response times was analyzed using ImageJ software. A line graph was plotted with the time as the abscissa and the color intensity as the ordinate, and the results are as Figure 3 shown in Figure b. It can be seen from the figure that in the range of 0 - 50 min, there is a good linear relationship between the color intensity and the response time. The specific simulation results are as
[0044] shown in Figure c. Figure 3The G value increased from 20 to 44 in the first 5 min, and an obvious color change was observed with the naked eye, indicating that the qualitative detection had been completed. At the 50th min, the reaction of the ASZ@CM sensor to F - had reached saturation, and the measured color intensity was 186. From the 5th min to the 50th min, the response of the ASZ@CM sensor to F - showed a good linear relationship (R 2 = 0.9980). All the above results indicate that the ASZ@CM sensor can complete the qualitative detection of F - within 5 min and the quantitative detection of F - within 50 min.
[0045] 4. Actual sample testing
[0046] Through the standard addition recovery experiment of actual samples, the performance of the ASZ@CM sensor product in actual application was analyzed and evaluated, providing important data support for its improvement and development under real application conditions.
[0047] Using lake water and tap water as solvents, solutions with F - concentrations of 1, 10, 20, and 25 mg / L were prepared respectively. 10 mL of each solution was taken and immersed in a piece of ASZ@CM sensor respectively. After 50 min, the color was recorded with a camera as shown in Figure 4 a - b. The detection value with the naked eye can be obtained using the standard colorimetric card in Figure 2 b. In addition, the ImageJ software was used to analyze the color intensity and combined it with the linear equation in Figure 2 c - d to calculate a more accurate value. The detection results were summarized, and the results are shown in Table 2.
[0048] Table 2 Detection results of F - in lake water and tap water by the ASZ@CM sensor
[0049]
[0050] As can be seen from Figure 4 , the ASZ@CM sensor responded effectively to F - , especially when the F - concentration was 10 mg / L and 20 mg / L, the recovery rate of the ASZ@CM sensor was close to 100%. This result indicates that the ASZ@CM sensor provided by the present invention has important practical value in the visual colorimetric detection of outdoor sewage.
[0051] Example 2
[0052] Dissolve 14 g of sodium hydroxide and 24 g of urea in 162 mL of water. After mixing evenly, freeze it to -12.5 °C, then add 8.3 g of cotton linter and stir rapidly for 10 min to obtain an alkaline cellulose sol. Centrifuge and defoam the alkaline cellulose sol at a speed of 4000 rpm for 10 min, then disperse it on the glass surface by the delayed flow method. Then immerse the glass in dilute sulfuric acid (concentration: 3 wt%) to solidify the sol into a film. After removing the film, rinse it with deionized water until neutral and cut it into a square with a side length of 1 cm to obtain a cellulose-based membrane.
[0053] Dissolve 0.08 g of ZrOCl₂·8H₂O in 200 mL of deionized water to prepare a zirconium salt solution with a concentration of 0.4 g / L. Immerse 5 g of the cellulose-based membrane in the above zirconium salt solution, and magnetically stir and adsorb the resulting mixture at room temperature for 4 h. Then vacuum filter to remove the supernatant, and repeatedly wash the remaining wet membrane with deionized water until neutral to obtain a zirconium-loaded cellulose membrane Zr@CM.
[0054] Using deionized water as the solvent, prepare 200 mL of an alizarin red S (ARs) solution with a concentration of 0.4 g / L. Immerse the Zr@CM prepared in the previous step in the ARs solution, adjust the pH of the solution to 3.5 with dilute hydrochloric acid, and mix and react at 10 °C for 4 h. After the reaction, take out the wet membrane and repeatedly wash it 3 times with distilled water to obtain an alizarin sulfonic acid zirconium-loaded cellulose membrane ASZ@CM sensor. Store the ASZ@CM sensor in distilled water for later use.
[0055] The product was tested according to the method in Reference Example 1, and the results were similar to those in Example 1.
[0056] Example 3
[0057] Dissolve 14 g of sodium hydroxide and 24 g of urea in 162 mL of water. After mixing evenly, freeze it to -12.5 °C, then add 8.3 g of cotton linter and stir rapidly for 10 min to obtain an alkaline cellulose sol. Centrifuge and defoam the alkaline cellulose sol at a speed of 4000 rpm for 10 min, then disperse it on the glass surface by the delayed flow method. Then immerse the glass in dilute sulfuric acid (concentration: 3 wt%) to solidify the sol into a film. After removing the film, rinse it with deionized water until neutral and cut it into a square with a side length of 1 cm to obtain a cellulose-based membrane.
[0058] Dissolve 0.08 g of ZrOCl₂·8H₂O in 200 mL of deionized water to prepare a zirconium salt solution with a concentration of 0.4 g / L. Immerse 5 g of the cellulose-based membrane in the above zirconium salt solution, and magnetically stir and adsorb the resulting mixture at room temperature for 4 h. Then vacuum filter to remove the supernatant, and repeatedly wash the remaining wet membrane with deionized water until neutral to obtain a zirconium-loaded cellulose membrane Zr@CM.
[0059] Using deionized water as the solvent, 200 mL of an alizarin red S (ARs) solution with a concentration of 0.4 g / L was prepared. The Zr@CM prepared in the previous step was immersed in the ARs solution, and the pH of the solution was adjusted to 4.2 with dilute hydrochloric acid. The mixture was reacted at 30 °C for 4 h. After the reaction, the wet membrane was taken out and washed repeatedly with distilled water 3 times to obtain an alizarin sulfonate zirconium-loaded cellulose membrane ASZ@CM sensor. The ASZ@CM sensor was stored in distilled water for later use.
[0060] The product was tested according to the method in Reference Example 1, and the results were similar to those in Example 1.
[0061] Example 4
[0062] 14 g of sodium hydroxide and 24 g of urea were dissolved in 162 mL of water. After mixing evenly, it was frozen to -12.5 °C. Then 8.3 g of cotton linters was added and stirred rapidly for 10 min to obtain an alkaline cellulose sol. The alkaline cellulose sol was centrifugally defoamed at a rotation speed of 4000 rpm for 10 min. Then it was dispersed on the glass surface by the delayed flow method. Then the glass was immersed in dilute sulfuric acid (concentration: 3 wt%) to solidify the sol into a film. After removing the film, it was rinsed with deionized water until neutral and cut into squares with a side length of 1 cm to obtain a cellulose-based membrane.
[0063] 0.08 g of ZrOCl2·8H2O was dissolved in 200 mL of deionized water to prepare a zirconium salt solution with a concentration of 0.4 g / L. 5 g of the cellulose-based membrane was immersed in the above zirconium salt solution. The resulting mixture was magnetically stirred and adsorbed at room temperature for 3 h. Then the supernatant was removed by vacuum filtration. The remaining wet membrane was repeatedly washed with deionized water until neutral to obtain a zirconium-loaded cellulose membrane Zr@CM.
[0064] Using deionized water as the solvent, 200 mL of an alizarin red S (ARs) solution with a concentration of 0.4 g / L was prepared. The Zr@CM prepared in the previous step was immersed in the ARs solution, and the pH of the solution was adjusted to 3.84 with dilute hydrochloric acid. The mixture was reacted at 10 °C for 4 h. After the reaction, the wet membrane was taken out and washed repeatedly with distilled water 3 times to obtain an alizarin sulfonate zirconium-loaded cellulose membrane ASZ@CM sensor. The ASZ@CM sensor was stored in distilled water for later use.
[0065] The product was tested according to the method in Reference Example 1, and the results were similar to those in Example 1.
[0066] Example 5
[0067] Dissolve 14 g of sodium hydroxide and 24 g of urea in 162 mL of water. After mixing evenly, freeze it to -12.5 °C. Then add 8.3 g of cotton linter and stir rapidly for 10 min to obtain an alkaline cellulose sol. Centrifuge and defoam the alkaline cellulose sol at a speed of 4000 rpm for 10 min. Then disperse it on the glass surface by the delayed flow method. Next, immerse the glass in dilute sulfuric acid (concentration: 3 wt%) to solidify the sol into a film. After removing the film, rinse it with deionized water until neutral and cut it into squares with a side length of 1 cm to obtain a cellulose-based membrane.
[0068] Dissolve 0.08 g of ZrOCl2·8H2O in 200 mL of deionized water to prepare a zirconium salt solution with a concentration of 0.4 g / L. Immerse 5 g of the cellulose-based membrane in the above zirconium salt solution. Magnetically stir and adsorb the resulting mixture at room temperature for 5 h. Then vacuum filter to remove the supernatant. Wash the remaining wet membrane repeatedly with deionized water until neutral to obtain a zirconium-loaded cellulose membrane Zr@CM.
[0069] Using deionized water as the solvent, prepare 200 mL of an alizarin red S (ARs) solution with a concentration of 0.4 g / L. Immerse the Zr@CM prepared in the previous step in the ARs solution, adjust the pH of the solution to 3.84 with dilute hydrochloric acid, and mix and react at 30 °C for 4 h. After the reaction, take out the wet membrane and wash it repeatedly with distilled water 3 times to obtain an alizarin sulfonate zirconium-loaded cellulose membrane ASZ@CM sensor. Store the ASZ@CM sensor in distilled water for later use.
[0070] The product was tested according to the method in Reference Example 1, and the results were similar to those in Example 1.
Claims
1. A visual colorimetric sensor, characterized in that: The sensor uses a cellulose membrane as the substrate, and zirconium alizarin sulfonate is loaded on the cellulose membrane substrate through hydrogen bonds.
2. The visual colorimetric sensor according to claim 1, characterized in that: The content of zirconium alizarin sulfonate in the visual colorimetric sensor does not exceed 1.6 mg / g.
3. The preparation method of the visual colorimetric sensor according to any one of claims 1-2, characterized in that The method includes: mixing a zirconium salt solution with a cellulose membrane for adsorption to obtain a zirconium-loaded cellulose membrane; under acidic conditions, mixing an alizarin sulfonate solution with the zirconium-loaded cellulose membrane for reaction to obtain a cellulose membrane sensor loaded with zirconium alizarin sulfonate.
4. The method according to claim 3, wherein: The zirconium salt solution is specifically an aqueous solution of ZrOCl or an aqueous solution of its hydrate, and the alizarin sulfonate solution is specifically an alizarin red S solution.
5. The method according to claim 3, wherein The preparation method of the cellulose membrane is as follows: sodium hydroxide, urea and short cotton lint are dissolved in water to form an alkaline cellulose sol in a mass ratio of 10-20:20-30:5-15, and after defoaming treatment, a film is formed. The wet film is placed in an acidic solution for curing to obtain a cellulose-based membrane.
6. The method according to claim 3, characterized in that: The concentrations of both the zirconium salt solution and the alizarin sulfonate solution are 0.1-1.2 g / L, and the mass ratio of the zirconium salt to the cellulose membrane during mixing is 0.6-1.0:4-6.
7. The method according to claim 3, wherein: When the zirconium salt solution is mixed with the cellulose membrane for adsorption, the temperature is 10-30 °C, the adsorption time is 3-5 h. After adsorption, solid-liquid separation is carried out and the wet membrane is washed thoroughly with water to obtain a zirconium-loaded cellulose membrane.
8. The method according to claim 3, characterized in that: The acidic condition is specifically pH = 3.5-4.2, and the mass ratio of the alizarin sulfonate to the zirconium-loaded cellulose membrane is 10:1-16.
9. Application of the visual colorimetric sensor according to any one of claims 1-2 in detecting fluoride ions.
10. The application according to claim 9, characterized in that: The detection object of the application is a solution or a solid or gas that can be formulated into a solution, the detection site is indoor or outdoor, and the detection limit of the visual colorimetric sensor for fluoride ions is 0.5 mg / L.