Test paper for detecting alum in water as well as preparation and application of test paper

Abstract

The invention discloses water quality alum detection test paper and preparation and application thereof.The detection test paper is prepared through a two-step drying method and comprises the steps that firstly, filter paper is soaked in a first solution and dried after soaking is completed, and prepared test paper A is obtained; the first solution is a mixed solution of 1, 2-cyclohexanediamine tetraacetic acid, citric acid, thiourea, ethylenediamine tetraacetic acid and sodium dihydrogen phosphate, and the solvent is pure water; then immersing the prepared test paper A into a second solution for soaking, and drying after soaking to obtain test paper B; the second solution is a mixed solution of 5-sulfo-4 '-diethylamino-2, 2'-dihydroxyazobenzene and polyoxyethylene lauryl ether, and the solvent is absolute ethyl alcohol; and finally, cutting the dried test paper B into a preset size, pasting the cut test paper B on a PVC strip with a preset size to obtain the test paper, and hermetically storing the test paper in a dark place. When the detection test paper is used for detecting alum in water, the operation is simple and convenient, and the anti-interference capability is strong.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality detection, and in particular to a water quality alum detection test paper and a preparation and application thereof. Background Art

[0002] The vanadium content in natural water is very low, about 1~10μg / L, and generally does not cause toxic effects on humans, animals and plants. When the vanadium concentration is 0.8mg / L, the water has a peculiar smell; 10mg / L can inhibit ammoniation and nitrification, and reduce the self-purification capacity of sewage; when the concentration is 10~20mg / L, it can inhibit the growth of crops such as soybeans. The toxicity of metallic vanadium is very low, but its compounds are moderately toxic to humans and animals, and the toxicity of vanadium compounds increases with the increase of their valence. Pentavalent vanadium has the greatest toxicity and stronger mobility.

[0003] The mining, smelting and use of vanadium ore will cause a large amount of vanadium to enter the environment; vanadium in the atmosphere enters the soil through its own sedimentation or rainwater leaching; vanadium in wastewater enters the soil through the adhesion of minerals or organic matter; the stacking and landfill of vanadium-containing waste will also increase the vanadium content in the soil; geological weathering and dissolution of underground vanadium-containing minerals will cause metallic vanadium to accumulate in groundwater; vanadium in the soil will also migrate to groundwater with the leaching of rainwater.

[0004] Alum is also often used as an additive for alloy steel and a catalyst in the chemical industry, and is used in aerospace, chemistry, batteries, pigments, glass, optics, medicine, etc. Therefore, industrial wastewater in these fields often contains alum, causing environmental pollution.

[0005] Existing alum detection methods include atomic absorption, tantalum reagent extraction photometry and catalytic polarography. The atomic absorption method requires expensive instruments and professional operators, and must be carried out in the laboratory, and cannot be detected in the field. The copper-iron reagent required for catalytic polarography needs to be stored away from light and is sensitive to air and light. It is very easy to change color and is very unstable after being configured into a solution, so it needs to be prepared and used immediately, which is not convenient for real-time detection on site. Tantalum reagent extraction photometry requires chloroform as an extraction reagent. Although some interfering ions are shielded, the reagent is not environmentally friendly, toxic, irritating and anesthetic, has the potential to cause cancer, and is harmful to organs. Summary of the invention

[0006] The present application provides a test paper for detecting alum in water quality, and its preparation and application. A test paper for detecting alum in water quality is prepared by using 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene as a color developer, and the alum detection test paper with anti-interference ability can be used to directly visually semi-quantitatively determine the degree of alum contamination in the field, avoiding the use of chloroform.

[0007] A method for preparing a water quality alum detection test paper comprises: (1) soaking the filter paper in a first solution, and drying after soaking to obtain a preliminary test paper A; the first solution is a mixed solution of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate, and the solvent is pure water; wherein the concentrations of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate are 5-100 g / L, 1-10 g / L, 50-100 g / L, 5-25 g / L and 10-50 g / L, respectively; (2) immersing the prepared test paper A in a second solution, and drying the solution after immersion to obtain a test paper B; the second solution is a mixed solution of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether, and the solvent is anhydrous ethanol; wherein the concentrations of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether are 2-10 g / L and 5-15 g / L, respectively; (3) Cut the dried test paper B into a preset size and stick it on a PVC strip of preset size to obtain the test paper, which is then stored in a sealed container away from light.

[0008] Optionally, the drying temperature in step (1) is 90-95°C; the drying temperature in step (2) is 50-60°C.

[0009] The preparation of the test paper of the present application, on the one hand, uses 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene as a color developer, 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene forms a yellow complex with pentavalent alum in wastewater, and alum detection test paper with anti-interference ability is prepared, which can directly visually semi-quantitatively judge the degree of alum pollution in the field, avoiding the use of chloroform; on the other hand, a two-step drying method is adopted, the effectiveness of the baked test paper is improved, and the paper is not prone to background color. The first reagent is soluble in water and can be dried at high temperature to shorten the preparation time. The second reagent is sensitive to temperature, and the second drying adopts a low-temperature drying method.

[0010] Optionally, the filter paper is medium-speed qualitative filter paper.

[0011] Optionally, the soaking time in steps (1) and (2) is 10 to 20 seconds.

[0012] Optionally, in steps (1) and (2), filter paper with a diameter of 7 cm is soaked in 10-15 mL of the corresponding solution.

[0013] Optionally, in the first solution, the concentrations of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate are 5~20 g / L, 3~6 g / L, 50~60 g / L, 15~25 g / L and 10~20 g / L, respectively; in the second solution, the concentrations of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether are 8~10 g / L and 8~12 g / L, respectively.

[0014] Most preferably, in the first solution, the concentrations of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate are 10 g / L, 5 g / L, 50 g / L, 20 g / L and 10 g / L, respectively; in the second solution, the concentrations of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether are 10 g / L and 10 g / L, respectively.

[0015] Optionally, cut the test paper B into small pieces of 0.5CM*0.5CM and stick them on a 0.5CM*10CM PVC strip.

[0016] The present application also provides a test paper prepared by the preparation method.

[0017] The present application also provides a colorimetric card prepared from the test paper.

[0018] The present application also provides a water quality alum detection kit, comprising the detection test paper and the colorimetric card.

[0019] Optionally, the alum ion concentration gradient of the colorimetric card is 0-1-3-10-30-50-70-100 mg / L.

[0020] The present application also provides a method for detecting alum in water using the detection kit, comprising: Take a water sample to be tested, insert the test paper into the water sample for 2-3 seconds, take it out and lay it flat for color development for 50-70 seconds, compare it with the colorimetric card after color development, and measure the concentration of alum ions in the water sample to be tested.

[0021] Optionally, the water sample to be tested is a standard solution containing vanadium and a water sample actually contaminated by vanadium.

[0022] Optionally, the concentration of alum ions in the water sample to be tested is 0-100 mg / L.

[0023] Optionally, the color development reaction time is 60s.

[0024] Compared with the prior art, the present invention has at least one of the following beneficial effects: (1) The test paper of the present application can be used to directly visually semi-quantitatively determine the degree of alum contamination in the field, avoiding the use of chloroform.

[0025] (2) The test paper of the present application is prepared by a two-step drying method, the effectiveness of the baked test paper is improved, and the paper is not prone to background color.

[0026] (3) The test paper detection method of the present application is simple and has strong anti-interference ability.

[0027] (4) This test paper is easy to carry and suitable for field use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the test paper diagram prepared in Example 1 (the gradient of the test paper for detecting vanadium ions is: 0-1-3-10-30-50-70-100 mg / L).

[0029] Figure 2 It is the color development result of the standard solution in Example 3.

[0030] Figure 3 These are the color development results of water samples contaminated with vanadium at different concentrations in Example 3.

[0031] Figure 4 This is the color development result when the vanadium pollution concentration in the water sample in Example 3 exceeds 100 mg / L.

[0032] Figure 5 This is the color development result of Comparative Example 1. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] This application uses a two-step drying method to prepare the test strips: (1) Add 0.5-10g of 1,2-cyclohexanediaminetetraacetic acid (CyDTA), 0.1-1g of citric acid, 5-10g of thiourea, 0.5-2.5g of ethylenediaminetetraacetic acid, and 1-5g of sodium dihydrogen phosphate to 100mL of pure water. After stirring to dissolve, take a medium-speed qualitative filter paper and immerse it. For every 10mL, immerse about one piece of qualitative filter paper with a diameter of 7CM. The immersion time should be more than 10 seconds. Then place the qualitative filter paper in a drying oven and dry it at 95℃ to obtain the preliminary test paper A.

[0036] (2) Add 0.2-1g of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and 0.5-1.5g of polyoxyethylene lauryl ether to 100mL of anhydrous ethanol, stir to dissolve, and then immerse the dried test paper A in it. For every 10mL, immerse about one sheet of qualitative filter paper with a diameter of 7CM. The immersion time should be more than 10 seconds. Then put the qualitative filter paper in a drying oven and dry it at 60℃ to obtain test paper B.

[0037] (3) Cut the dried test paper B into small pieces of 0.5CM*0.5CM, stick them onto a 0.5CM*10CM PVC strip, place them in a test paper bucket, and keep them airtight away from light.

[0038] All reagents used are commercially available.

[0039] The following is described with specific examples: Example 1 Two-step drying method to prepare test paper: (1) Add 1g of 1,2-cyclohexanediaminetetraacetic acid (CyDTA), 0.5g of citric acid, 5g of thiourea, 2g of ethylenediaminetetraacetic acid, and 1g of sodium dihydrogen phosphate to 100mL of pure water. After stirring to dissolve, take a medium-speed qualitative filter paper and immerse it. For every 10mL, immerse about one piece of qualitative filter paper with a diameter of 7CM. The immersion time should be more than 10 seconds. Then place the qualitative filter paper in a drying oven and dry it at 95℃ to obtain the preliminary test paper A.

[0040] (2) Add 1g of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and 1g of polyoxyethylene lauryl ether to 100mL of anhydrous ethanol, stir to dissolve, and then immerse the dried test paper A in it. For every 10mL, immerse about one sheet of qualitative filter paper with a diameter of 7CM. The immersion time should be more than 10 seconds. Then put the qualitative filter paper in a drying oven and dry it at 60℃ to obtain test paper B.

[0041] (3) Cut the dried test paper B into small pieces of 0.5CM*0.5CM, stick them onto a 0.5CM*10CM PVC strip, place them in a test paper bucket, and keep them airtight away from light.

[0042] Example 2 Preparation of colorimetric card: (1) Prepare standard solutions of vanadium ion with concentrations of 0-1-3-10-30-50-70-100 mg / L. The preparation process is as follows: Vanadium standard solution was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a concentration of 1000 mg / L.

[0043] Vanadium standard working solution: Pipette 0 mL, 0.1 mL, 0.3 mL, 1 mL, 3 mL, 5 mL, 7 mL, and 10 mL of vanadium standard stock solution into a 100 mL volumetric flask, respectively, and dilute to the scale with pure water. The vanadium concentrations are 0, 1 mg / L, 3 mg / L, 10 mg / L, 30 mg / L, 50 mg / L, 70 mg / L, and 100 mg / L, respectively. (2) The test paper prepared in Example 1 was inserted into a standard solution of alum ions of different concentrations (immersion time was 3 seconds), taken out and laid flat, and color development was carried out for 60 seconds. After the color development was completed, a colorimetric card was prepared according to the color development of the test paper. The results were as follows: Figure 1 shown.

[0044] Example 3 Take 0.5 mL of the standard solution prepared in Example 2, and then insert the test strip prepared in Example 1 into the standard solution for 2-3 seconds, then take it out and lay it flat, let it react for 1 minute, and compare the colors of the reaction area of ​​the test strip. The results are as follows: Figure 2 As shown, the concentration was determined by visual colorimetry, and the colorimetric result was basically consistent with the concentration of the standard solution.

[0045] Randomly draw water samples with different concentrations of vanadium pollution (the vanadium concentrations of water samples determined by tantalum reagent (BPHA) extraction spectrophotometry (HZ-HJ-SZ-0088) are 5mg / L, 10mg / L, 30mg / L, 60mg / L and 100mg / L respectively), and after determination with test paper, the color development results are as follows Figure 3 , and Figure 1 Compare with the color chart shown. Figure 3 The alum concentrations of the water samples from left to right are 3-10 mg / L, 10 mg / L, 30 mg / L, 50-70 mg / L and 100 mg / L respectively. The results of colorimetric judgment are basically consistent with the results of tantalum reagent (BPHA) extraction spectrophotometry (HZ-HJ-SZ-0088).

[0046] When the vanadium pollution concentration in the water sample exceeds 100 mg / L, the colorimetric results are as follows: Figure 4 , its color is darker than the 100 mg / L in the color card. Figure 4 The vanadium concentrations of the water samples from left to right are 120 mg / L, 200 mg / L and 300 mg / L respectively.

[0047] Comparative Example 1 One-step drying method to prepare test paper: (1) Add 1 g of 1,2-cyclohexanediaminetetraacetic acid (CyDTA), 0.5 g of citric acid, 5 g of thiourea, 2 g of ethylenediaminetetraacetic acid, and 1 g of sodium dihydrogen phosphate to 100 mL of pure water and stir to dissolve to obtain test solution A.

[0048] Add 1 g of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and 1 g of polyoxyethylene lauryl ether to 100 mL of anhydrous ethanol and stir to dissolve to obtain test solution B.

[0049] After mixing test solution A and test solution B, take a medium-speed qualitative filter paper and immerse it in the mixture. For every 10 mL, immerse one piece of qualitative filter paper with a diameter of 7 cm. The immersion time should be more than 10 seconds. Then dry the qualitative filter paper in a drying oven at 95°C to obtain the test paper.

[0050] Cut the dried test paper into small pieces of 0.5CM*0.5CM, stick them onto a 0.5CM*10CM PVC strip, place them in a test paper bucket, and keep them airtight away from light.

[0051] The prepared test paper was inserted into the different concentrations of vanadium ion standard solutions configured in Example 2 (immersion time was 3 seconds), taken out and laid flat, and the color reaction was carried out for 60 seconds. The color development was as follows: Figure 5 ,Depend on Figure 5 The results show that the test paper obtained by one-step drying has an impure base color. At the same time, the color development is uneven during colorimetry and the color development is not ideal.

[0052] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A preparation method for a water quality alum test paper, characterized in that, include: (1) soaking the filter paper in the first solution, and drying it after soaking to obtain the prepared test paper A; The first solution is a mixed solution of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate, and the solvent is pure water; wherein the concentrations of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate are 5-100 g / L, 1-10 g / L, 50-100 g / L, 5-25 g / L and 10-50 g / L, respectively; (2) immersing the prepared test paper A in a second solution, and drying the solution after immersion to obtain a test paper B; the second solution is a mixed solution of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether, and the solvent is anhydrous ethanol or methanol; wherein the concentrations of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether are 2-10 g / L and 5-15 g / L, respectively; (3) Cut the dried test paper B into a preset size and stick it on a PVC strip of preset size to obtain the test paper, which is then stored in a sealed container away from light.

2. The preparation method according to claim 1, characterized in that: The drying temperature in step (1) is 90-95°C; the drying temperature in step (2) is 50-60°C.

3. The preparation method according to claim 1, characterized in that: The filter paper is a medium-speed qualitative filter paper; the soaking time in steps (1) and (2) is 10 to 20 seconds.

4. The preparation method according to claim 1, characterized in that: In steps (1) and (2), filter paper with a diameter of 7 cm is soaked in 10-15 mL of the corresponding solution.

5. The preparation method according to claim 1, characterized in that: In the first solution, the concentrations of 1,2-cyclohexanediaminetetraacetic acid, citric acid, thiourea, ethylenediaminetetraacetic acid and sodium dihydrogen phosphate are 5~20 g / L, 3~6 g / L, 50~60 g / L, 15~25 g / L and 10~20 g / L, respectively; in the second solution, the concentrations of 5-sulfo-4'-diethylamino-2,2'-dihydroxyazobenzene and polyoxyethylene lauryl ether are 8~10 g / L and 8~12 g / L, respectively.

6. A test paper prepared by the preparation method according to any one of claims 1 to 5.

7. A colorimetric card prepared from the test paper according to claim 6.

8. A water quality alum detection kit, characterized in that, It comprises the test paper as claimed in claim 6 and the colorimetric card as claimed in claim 7.

9. The detection kit according to claim 8, characterized in that The alum ion concentration gradient of the colorimetric card is 0-1-3-10-30-50-70-100 mg / L.

10. A method for detecting alum in water quality using the detection kit according to claim 8 or 9, characterized in that: include: Take a water sample to be tested, insert the test paper into the water sample for 2-3 seconds, take it out and lay it flat for color development for 50-70 seconds, compare it with the colorimetric card after color development, and measure the concentration of alum ions in the water sample to be tested.

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