Synchronous test paper for Fe < 3 + > and Fe < 2 + > as well as preparation method and application of synchronous test paper

Abstract

The invention discloses synchronous test paper for Fe < 3 + > and Fe < 2 + > as well as a preparation method and application of the synchronous test paper, and effectively solves the problem that high-concentration Fe < 3 + > and Fe < 2 + > in a boiler chemical cleaning solution are difficult to rapidly, accurately and simultaneously detect. The detection test paper is provided with isolated first and second color developing regions, provides an independent space for Fe < 3 + > and total iron detection, and is anti-interference and accurate. A potassium thiocyanate-hydrochloric acid color developing agent is specially used for measuring Fe < 3 + > in the first color developing area, a phenanthroline-ascorbic acid color developing agent is used for measuring total iron in the second color developing area, and the concentration of Fe < 2 + > is calculated in a combined mode. A standard colorimetric card is matched, color blocks accurately correspond to the concentration range (0-5000 mg / L), the common iron ion concentration is covered, and a comparison basis is provided for detection. During detection, information can be rapidly and visually obtained by comparing the color of the color developing area with the color chart, operation is easy and convenient, complex equipment and professionals are not needed, and field requirements are met. And the scheme is resistant to interference of high-concentration and complex components, and the result is real and reliable.

Description

Technical Field

[0001] This invention belongs to the field of industrial chemical cleaning technology, and relates to a Fe 3+ and Fe 2+ Synchronous test strips, their preparation methods, and applications. Background Technology

[0002] In the chemical cleaning process of boilers, chemical cleaning solutions (such as hydrochloric acid, citric acid, and various complex organic acids) play a crucial role, effectively removing rust, scale, and other impurities from the boiler's inner walls, ensuring efficient boiler operation. Accurate detection of iron ion concentration in the cleaning solution is of paramount importance. It not only precisely determines the cleaning endpoint and evaluates the cleaning agent's performance to ensure cleaning effectiveness, but also prevents boiler corrosion and secondary deposits, maintaining its operational safety. Furthermore, it helps optimize the amount of cleaning solution used, reduce equipment wear to control costs, and provides a basis for wastewater treatment to protect the environment. In particular, simultaneous detection of Fe in the cleaning solution is crucial. 3+ and Fe 2+ Even more crucially, Fe 3+ Mostly derived from oxidation products such as rust, Fe 2+ These are metal corrosion products. The content and ratio of these two substances can comprehensively reflect the cleaning process, effect, and corrosion status of the boiler metal, providing a key basis for adjusting the cleaning plan.

[0003] However, the iron ion concentration in boiler chemical cleaning fluids is typically at a high level, ranging from hundreds to tens of thousands of mg / L, which makes the detection of iron ion concentration, especially Fe, difficult. 3+ and Fe 2+ Simultaneous detection presents significant challenges. Currently common detection methods have many limitations.

[0004] Spectrophotometry determines the concentration of iron ions based on the absorption characteristics of substances to light of different wavelengths. Theoretically, it can detect Fe... 3+ and Fe 2+ However, this requires sophisticated optical instruments, such as spectrophotometers. These instruments are expensive, bulky, complex to operate, and have high environmental requirements. At project sites, there is often a lack of the necessary supporting facilities and professional operators, making it difficult to meet the required testing conditions, achieve convenient on-site testing, and quickly and simultaneously obtain Fe... 3+ and Fe 2+ Concentration information.

[0005] The potassium thiocyanate colorimetric titration method is a typical traditional titration method. Although it can be used to detect iron ion concentration, it also has limitations in simultaneously detecting Fe. 3+ and Fe 2+This method has significant drawbacks. Firstly, the operation is cumbersome, requiring strict control over multiple steps, including the order of reagent addition, reaction time, and titration rate. Deviations in any step can affect the accuracy of the test results. In situations with limited time and resources at the project site, it's difficult to guarantee standardized and precise operation, failing to meet the need for rapid on-site guidance of cleaning processes. Secondly, in high-concentration iron ion ranges, this method is prone to saturation. When the iron ion concentration is too high, the colorimetric reaction reaches its limit, failing to accurately reflect the actual iron ion content, leading to distorted test results. Furthermore, this method is susceptible to interference from the pH of the cleaning solution and the oxidizing / reducing agent. Different pH values ​​affect the progress of the colorimetric reaction and color stability. The oxidizing / reducing agent may undergo other chemical reactions with iron ions, interfering with the normal reaction between iron ions and reagents, further reducing the reliability of the test results and hindering the accurate detection of Fe. 3+ and Fe 2+ It became extremely difficult. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides an Fe 3+ and Fe 2+ This invention relates to a synchronous test strip, its preparation method, and its application, thereby solving the problem of the inability of existing technologies to quickly and accurately test high-concentration Fe in boiler chemical cleaning fluids simultaneously. 3+ and Fe 2+ Technical issues.

[0007] This invention is achieved through the following technical solution: A Fe 3+ and Fe 2+ The synchronous test strips include test strips and standard colorimetric cards; The test strip includes a first color development area and a second color development area that are isolated from each other. The first color development area is a filter paper that has adsorbed potassium thiocyanate-hydrochloric acid color developer, and the second color development area is a filter paper that has adsorbed phenanthrene-ascorbic acid color developer. The standard colorimetric card includes a first colorimetric area and a second colorimetric area; the first colorimetric area consists of several color patches, from light to dark, corresponding to Fe. 3+ The concentration gradually increases from 0 to 5000 mg / L; the second colorimetric zone consists of several color patches, which, from light to dark, correspond to the total iron concentration gradually increasing from 0 to 5000 mg / L.

[0008] Preferably, the thickness of the first color development area and the second color development area is 0.3~0.7mm.

[0009] Preferably, an isolation zone is provided between the first color development zone and the second color development zone; the surface of the isolation zone is coated with hydrophobic wax.

[0010] Preferably, the width of the isolation zone is 2-3 mm.

[0011] Preferably, an isolation layer is provided on one side of both the first color development area and the second color development area.

[0012] Preferably, the first colorimetric area consists of six color blocks, with colors from light to dark precisely corresponding to Fe. 3+ The concentrations are 500, 1000, 2000, 3000, 4000, and 5000 mg / L.

[0013] Preferably, the second colorimetric zone consists of six color blocks, corresponding to total iron concentrations of 500, 1000, 2000, 3000, 4000, and 5000 mg / L.

[0014] The above-mentioned Fe 3+ and Fe 2+ The method for preparing a synchronous test strip involves dissolving potassium thiocyanate and a surfactant in hydrochloric acid solution to obtain a first colorimetric solution. A portion of the test strip substrate is immersed in the first colorimetric solution and then vacuum dried to form a first colorimetric area on the test strip substrate. A second colorimetric solution is prepared by dissolving phenanthrene, ascorbic acid, and polyvinylpyrrolidone in acetate buffer solution. Another portion of the test strip substrate is immersed in the second colorimetric solution and then vacuum dried to form a second colorimetric area on the test strip substrate, thus obtaining the Fe... 3+ and Fe 2+ Synchronous test strips.

[0015] Preferably, an isolation layer is provided on one side of the first color development area and the second color development area by hot pressing.

[0016] The above-mentioned Fe 3+ and Fe 2+ Synchronous test strips for Fe in boiler chemical cleaning 3+ and Fe 2+ Applications in detection.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a Fe 3+ and Fe 2+ This synchronous test strip, through its unique design, effectively solves the problem that existing technologies cannot quickly and accurately test high-concentration Fe in boiler chemical cleaning fluids simultaneously. 3+ and Fe 2+ The challenge lies in setting up isolated first and second color development zones on the test strip, for Fe... 3+ The total iron detection provides independent reaction spaces to avoid mutual interference and ensure detection accuracy. The first colorimetric zone is loaded with a potassium thiocyanate-hydrochloric acid colorimetric reagent, which can react with Fe... 3+A specific colorimetric reaction occurs to form a blood-red complex, which is specifically used to detect Fe. 3+ Concentration; the second chromogenic region is loaded with a phenanthroxazine-ascorbic acid chromogenic agent, which can react with Fe... 2+ A colorimetric reaction occurs, producing a purple-red substance, which is used to detect the total iron concentration. The Fe concentration is then calculated by combining these two methods. 2+ Concentration, enabling simultaneous detection. The standard colorimetric card is included; the first colorimetric zone shows color blocks ranging from light to dark corresponding to Fe. 3+ The concentration gradually increases from 0 to 5000 mg / L. The second colorimetric zone corresponds to the same range of total iron concentration, covering the common iron ion concentration range in boiler chemical cleaning fluids, providing an accurate basis for detection. Testing personnel can quickly and intuitively obtain the Fe concentration by comparing the color of the developing zone with the standard colorimetric card. 3+ This method provides information on total iron concentration, is simple and convenient to operate, requires no complex instruments or professional personnel, and meets the need for rapid on-site guidance of cleaning processes. Simultaneously, it overcomes the interference of high concentrations and complex components in the cleaning solution, and detects Fe in the first colorimetric zone. 3+ Unaffected by Fe 2+ Interference: The detection of total iron in the second colorimetric region is not affected by common ions, ensuring the accuracy and reliability of the detection results and effectively solving the problems existing in the current technology.

[0018] Furthermore, the thickness of the first and second colorimetric regions is 0.3~0.7 mm. From the perspective of the colorimetric reaction, this thickness range ensures that the colorimetric reagent has a sufficient amount to react with the Fe to be measured. 3+ The reagent must react fully with the total iron. If the strip is too thin, the amount of reagent will be insufficient, leading to incomplete color development, weak color change, and affecting the accuracy of the test. Conversely, if the strip is too thick, it will prolong the color development time and reduce the efficiency of the test. At the same time, an appropriate thickness allows the test strip to maintain good flexibility and mechanical strength, facilitating handling during the testing process, such as soaking and removing the strip, and reducing the possibility of damage.

[0019] Furthermore, an isolation zone is provided between the first and second colorimetric zones; the surface of the isolation zone is coated with hydrophobic wax, which can effectively prevent mutual interference between the two colorimetric zones. In the detection of boiler chemical cleaning fluids, the colorimetric reaction may be affected by the surrounding environment and other substances. The presence of the isolation zone can prevent the interpenetration of the colorimetric agent or reaction products, ensuring the Fe... 3+ The independence and accuracy of total iron testing.

[0020] Furthermore, the width of the isolation zone is 2-3mm, which provides sufficient isolation space to ensure the isolation effect without excessively occupying the effective area of ​​the test strip, allowing the color development area to have enough space for color development reaction and observation.

[0021] Furthermore, an isolation layer is provided on one side of both the first and second color development areas, which further enhances the test strip's anti-interference ability. It can prevent external substances from contaminating the color development areas, and also avoid indirect interference between color development areas, ensuring that the color development reaction takes place in a stable environment and improving the reliability of the test results.

[0022] Furthermore, the first colorimetric area consists of six color blocks, with colors ranging from light to dark precisely corresponding to Fe. 3+ The concentrations of Fe were 500, 1000, 2000, 3000, 4000, and 5000 mg / L. The second colorimetric area consisted of six color patches, corresponding to total iron concentrations of 500, 1000, 2000, 3000, 4000, and 5000 mg / L. This precise correspondence allowed testing personnel to more accurately interpret the results during colorimetric analysis, reducing human error. By comparing with the standard color patches, the Fe concentration could be quickly and intuitively determined. 3+ And the total iron concentration information, and then calculate Fe 2+ The concentration range corresponding to the color blocks can cover the common concentration range of iron ions in boiler chemical cleaning fluids, meeting the needs of actual detection and making the test strip widely applicable.

[0023] In addition, the present invention also discloses the above-mentioned Fe 3+ and Fe 2+ The method for preparing a synchronous test strip involves dissolving potassium thiocyanate and a surfactant in hydrochloric acid solution to obtain a first colorimetric solution. A portion of the test strip substrate is immersed in the first colorimetric solution and then vacuum dried to form a first colorimetric area on the test strip substrate. A second colorimetric solution is prepared by dissolving phenanthrene, ascorbic acid, and polyvinylpyrrolidone in acetate buffer solution. Another portion of the test strip substrate is immersed in the second colorimetric solution and then vacuum dried to form a second colorimetric area on the test strip substrate, thus obtaining the Fe... 3+ and Fe 2+ The method involves synchronous testing of test strips. It is simple to operate and easy to mass-produce.

[0024] Furthermore, by hot-pressing, an isolation layer is applied to one side of both the first and second colorimetric areas. This allows the isolation layer to bond tightly with the colorimetric areas, improving its adhesion and isolation effect, and further ensuring the test strip's detection performance. Simultaneously, the hot-pressing process is mature and can guarantee production consistency and stability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of the test strip in this invention; Figure 2 This is a schematic diagram of the structure of the standard colorimetric card in this invention.

[0027] Among them: 1. First color development area, 2. Second color development area, 3. First colorimetric area, 4. Second colorimetric area, 5. Isolation area. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0034] The present invention will now be described in further detail with reference to the accompanying drawings: like Figures 1-2 As shown, this invention provides a method for simultaneously detecting Fe in boiler chemical cleaning fluid. 3+ and Fe 2+ The synchronous test strips include test strips and standard colorimetric cards; The test strip includes a first colorimetric area 1 and a second colorimetric area 2, which are isolated from each other. The first colorimetric area 1 is filter paper adsorbed with potassium thiocyanate-hydrochloric acid colorimetric agent, and the second colorimetric area 2 is filter paper adsorbed with phenanthrene-ascorbic acid colorimetric agent. The first colorimetric area 1 is Fe 3+ The detection area, specifically the second color development area 2, is the total iron detection area; The standard colorimetric card includes a first colorimetric area 3 and a second colorimetric area 4; the first colorimetric area 3 consists of several color patches, which correspond to Fe from light to dark. 3+ The concentration gradually increases from 500 to 5000 mg / L; the second colorimetric zone 4 consists of several color blocks, which, from light to dark, correspond to the total iron concentration gradually increasing from 500 to 5000 mg / L.

[0035] The synchronous test strip in this invention mainly comprises two parts: the test strip and the standard colorimetric card. The test strip, as the core detection component, has a unique design structure. It includes an isolated first colorimetric zone 1, namely... Figure 1 Area A in the text, and the second colorimetric area 2, namely Figure 1 Region B is shown in the image. The first colorimetric region 1 contains a potassium thiocyanate-hydrochloric acid colorimetric reagent, designed based on the reaction of potassium thiocyanate with Fe... 3+ The principle behind the ability to produce a specific colorimetric reaction. When Fe... 3+ When present, it forms a blood-red complex with potassium thiocyanate; the intensity of the color visually reflects the presence of Fe. 3+The concentration. The second colorimetric region 2 is filter paper adsorbed with phenanthrene-ascorbic acid colorimetric agent, which can react with Fe. 2+ (Ascorbic acid will reduce Fe) 3+ Reduced to Fe 2+ A color reaction occurs, producing a purple-red substance, which is then used to detect the concentration of total iron.

[0036] The standard colorimetric card is an important tool used in conjunction with the test strips. It includes a first colorimetric area 3 and a second colorimetric area 4. The first colorimetric area 3 consists of several color patches, whose colors, from light to dark, correspond to Fe. 3+ The concentration gradually increases from 500 to 5000 mg / L. In one specific embodiment, the first colorimetric zone 3 consists of six color blocks, with colors from light to dark precisely corresponding to Fe. 3+ The concentrations are 500, 1000, 2000, 3000, 4000, and 5000 mg / L. Similarly, the second colorimetric zone 4 also consists of several color patches, with the color gradually increasing from light to dark, corresponding to a total iron concentration of 500-5000 mg / L. In a specific embodiment, it also consists of six color patches, corresponding to total iron concentrations of 500, 1000, 2000, 3000, 4000, and 5000 mg / L. This standard colorimetric card design allows testing personnel to quickly and accurately obtain the Fe concentration through simple comparison. 3+ Information on total iron concentration.

[0037] The first color development area 1 measures 2cm × 5cm, and the second color development area 2 measures 2cm × 5cm. This size design ensures sufficient color development area for easy observation and color comparison, while also making the overall structure of the test strip compact, easy to carry and use.

[0038] In a preferred embodiment, such as Figure 1 As shown, an isolation zone 5 is provided between the first colorimetric zone 1 and the second colorimetric zone 2. The width of the isolation zone 5 is 2-3 mm, preferably 2 mm, and its surface is coated with hydrophobic wax with a melting point of 60℃. The isolation zone effectively prevents mutual interference between the two colorimetric zones, ensuring the accuracy of the test results. The presence of the hydrophobic wax further enhances the isolation effect, preventing the cross-penetration of colorimetric reagents.

[0039] In a preferred embodiment, both the first colorimetric zone 1 and the second colorimetric zone 2 are made of glass fiber paper as the base material. Glass fiber paper possesses many characteristics suitable for use as a colorimetric zone material. It exhibits good chemical stability, maintaining its performance under certain acidic or alkaline environments and chemical substances, and is not prone to chemical reactions with colorimetric agents or other substances it may come into contact with, thus providing a stable foundation for the colorimetric reaction. Simultaneously, glass fiber paper also possesses a certain degree of mechanical strength, allowing it to withstand certain external forces during the use of the test paper, such as soaking, drying, and comparison, without easily breaking, ensuring the integrity and usability of the test paper.

[0040] Specific color developers were deposited on glass fiber paper to create color development areas. For the first color development area 1, a potassium thiocyanate-hydrochloric acid color developer was deposited. The combination of potassium thiocyanate and hydrochloric acid is based on its reaction with Fe... 3+ The principle behind the characteristic colorimetric reaction. When Fe... 3+ When present, it forms a blood-red complex with potassium thiocyanate; the color variation visually reflects the presence of Fe. 3+ The concentration of [unspecified substance]. The second chromogenic region 2 is deposited with phenanthroxazine-ascorbic acid chromogenic agent, which can react with Fe [unspecified substance]. 2+ (Ascorbic acid will reduce Fe) 3+ Reduced to Fe 2+ A color reaction occurs, producing a purple-red substance, which is used to detect the concentration of total iron.

[0041] To ensure that the colorimetric zones have adequate reaction space and material capacity, the thickness of both the first colorimetric zone 1 and the second colorimetric zone 2 is precisely controlled within the range of 0.3~0.7mm, preferably 0.5mm. This thickness ensures that the colorimetric reagent has sufficient quantity to react fully with the analyte ions, while also preventing the test strip from becoming too thick and heavy, thus affecting its ease of use and operation.

[0042] In a more preferred embodiment, to further improve the performance and accuracy of the test strip, an isolation layer is provided on one side of both the first colorimetric area 1 and the second colorimetric area 2. The isolation layer plays a crucial role in isolation and protection; it employs a hydrophobic design and is made of polypropylene film. The polypropylene film has excellent hydrophobicity, effectively preventing unintended penetration of moisture and other substances. During the use of the test strip, it may come into contact with cleaning solutions or other liquids. The hydrophobic properties of the isolation layer prevent these liquids from diffusing and interfering with each other between the colorimetric areas, ensuring that the colorimetric reactions of the first colorimetric area 1 and the second colorimetric area 2 can proceed independently and accurately. For example, it prevents liquid from the second colorimetric area 2 from penetrating into the first colorimetric area 1 and affecting Fe... 3+ The test results.

[0043] The isolation layer is 0.1 mm thick. This thickness design provides sufficient isolation without negatively impacting the overall structure and performance of the test strip. It is thin enough not to significantly increase the thickness and weight of the test strip, ensuring its flexibility and portability; at the same time, it is thick enough to effectively perform its hydrophobic isolation function, enabling accurate detection of Fe. 3+ The total iron concentration provides a reliable guarantee.

[0044] The first color-developing region 1 and the second color-developing region 2 are bonded and fixed to the isolation layer by heating and pressurization. During heating, the surface molecules of the isolation layer and the color-developing regions diffuse and permeate into each other, thereby achieving bonding between the two. During the heating process, the polypropylene film reaches a certain softening point. Applying pressure at this point allows the film to better adhere to the glass fiber paper, and after cooling, a firm fixed structure is formed.

[0045] In addition, the present invention also discloses a method for simultaneously detecting Fe in boiler chemical cleaning fluid. 3+ and Fe 2+ The preparation method of the synchronous test strip: dissolve potassium thiocyanate and surfactant in hydrochloric acid solution to prepare the first colorimetric solution, immerse a part of the test strip substrate in the first colorimetric solution, and then vacuum dry to form the first colorimetric area 1 on the test strip substrate; The surfactant was chosen to optimize the wetting and dispersibility of the colorimetric solution, thereby improving the sensitivity and uniformity of the colorimetric reaction. The surfactant used was Triton X-100, a polyoxyethylene ether nonionic surfactant whose molecular structure contains a polyoxyethylene group and a hydrophobic group. This structure gives it both hydrophilic and lipophilic properties.

[0046] Preferably, the concentration of the hydrochloric acid solution is 0.5~1 mol / L.

[0047] In a preferred embodiment, the above process is as follows: 10g of potassium thiocyanate and 1g of surfactant are dissolved in 100 mL of 1mol / L hydrochloric acid solution to prepare a first colorimetric solution; a portion of the test paper substrate is immersed in the first colorimetric solution for 10 min; and then vacuum dried at 45~55℃ to form a first colorimetric area 1 on the test paper substrate. Next, a second colorimetric solution is prepared by dissolving phenanthridine, ascorbic acid, and polyvinylpyrrolidone in an acetate buffer solution. Another part of the test paper substrate is immersed in the second colorimetric solution and then vacuum dried to form a second colorimetric area 2 on the test paper substrate. After being cut to a suitable size, it is sealed in an aluminum foil bag to complete the preparation of the synchronous test paper.

[0048] Preferably, the pH value of the acetate buffer solution is 3 to 5.

[0049] In a preferred embodiment, 3g phenanthridine, 1g ascorbic acid and 5g polyvinylpyrrolidone are dissolved in 100mL of acetate buffer with pH 4 to prepare a second colorimetric solution. Another part of the test paper substrate is immersed in the second colorimetric solution for 10min and then vacuum dried at 45~55℃ to form a second colorimetric area 2 on the test paper substrate. Furthermore, the present invention also provides an isolation layer on one side of the first colorimetric area 1 and the second colorimetric area 2. Specifically, a specially designed hot press can be used to place the isolation layer and the colorimetric area in a predetermined position, and then set appropriate temperature and pressure parameters. Generally, the temperature should be controlled within the softening temperature range of the polypropylene film, and the pressure should be adjusted according to the size and thickness of the test paper. For example, for this combination of 0.5mm thick glass fiber paper and 0.1mm thick polypropylene film, the temperature can be set at 120~150℃, and the pressure controlled at 0.5~1MPa. After continuous pressurization and heating for a period of time, the paper is removed and allowed to cool naturally.

[0050] This invention provides a method for simultaneously detecting Fe in boiler chemical cleaning fluid. 3+ and Fe 2+ Instructions for using the synchronous test strip: The operation of this synchronous test strip is relatively simple. Simply immerse the strip in the boiler cleaning solution for 1 second, then remove it and read the color depth of the developing area within the specified time. Specifically, read the blood-red depth of the first developing area 1 within 10 seconds, and compare it with the first colorimetric area 3 of the standard colorimetric card to determine the Fe content. 3+ The concentration was determined. After 30 seconds, the depth of the purplish-red color in the second colorimetric area 2 was read and compared with the second colorimetric area 4 of the standard colorimetric card to obtain the total iron concentration. Fe... 2+ The concentration can be obtained by subtracting Fe from the total iron concentration. 3+ The concentration was calculated. When the iron ion concentration in the cleaning solution is high, it needs to be diluted before comparison with the colorimetric card to ensure the accuracy of the test results.

[0051] This invention provides a method for simultaneously detecting Fe in boiler chemical cleaning fluid. 3+ and Fe 2+ The synchronous test strip, judging from the colorimetric range, has Fe... 3+ The colorimetric range for both total iron and iron is 0–5000 mg / L, which covers the common concentration range of iron ions in boiler chemical cleaning fluids, providing a basic range basis for detection. Regarding anti-interference performance, the first colorimetric region 1Fe… 3+ The detection is unaffected by Fe 2+ The interference makes it possible for Fe to coexist. 3+ and Fe 2+ In complex cleaning fluid environments, Fe can be measured relatively accurately and individually.3+ The content of Cu. However, the detection of total iron in the second colorimetric region 2 is not affected by Cu. 2+ Zn 2+ Ca 2+ The detection of common ions, such as iron ions, ensures the accuracy of total iron content test results and avoids interference from other common ions. High-temperature stability is also an important indicator in the detection process. The first colorimetric region 1 is stable at 80℃, meeting the detection requirements under certain high-temperature environments. However, the second colorimetric region 2 is stable below 60℃, requiring more stringent temperature control. In actual boiler chemical cleaning operations, the cleaning solution temperature may be high, necessitating closer attention to temperature control when detecting total iron content to ensure the reliability of the results.

[0052] Overall, the synchronous test strip in this invention has excellent color development range, high anti-interference ability and high temperature stability, which is of great significance for accurately detecting the iron ion content in boiler chemical cleaning fluid and guiding the adjustment and optimization of cleaning process.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A Fe 3+ and Fe 2+ The synchronous test strip is characterized by, This includes test strips and standard colorimetric cards; The test strip includes a first color development area (1) and a second color development area (2) that are isolated from each other. The first color development area (1) is a filter paper adsorbed with potassium thiocyanate-hydrochloric acid color developer, and the second color development area (2) is a filter paper adsorbed with phenanthrene-ascorbic acid color developer. The standard colorimetric card includes a first colorimetric area (3) and a second colorimetric area (4); the first colorimetric area (3) consists of several color blocks, which correspond to Fe from light to dark. 3+ The concentration gradually increases from 0 to 5000 mg / L; the second colorimetric zone (4) consists of several color blocks, which correspond to the total iron concentration gradually increasing from 0 to 5000 mg / L from light to dark.

2. The Fe according to claim 1 3+ and Fe 2+ The synchronous test strip is characterized by, The thickness of the first color development area (1) and the second color development area (2) is 0.3~0.7mm.

3. The Fe according to claim 1 3+ and Fe 2+ The synchronous test strip is characterized by, An isolation zone (5) is provided between the first color development zone (1) and the second color development zone (2); the surface of the isolation zone (5) is coated with hydrophobic wax.

4. The Fe according to claim 3 3+ and Fe 2+ The synchronous test strip is characterized by, The width of the isolation zone (5) is 2~3mm.

5. The Fe according to claim 1 3+ and Fe 2+ The synchronous test strip is characterized by, An isolation layer is provided on one side of both the first color development area (1) and the second color development area (2).

6. The Fe according to claim 1 3+ and Fe 2+ The synchronous test strip is characterized by, The first colorimetric area (3) consists of six color blocks, with colors from light to dark precisely corresponding to Fe. 3+ The concentrations are 500, 1000, 2000, 3000, 4000, and 5000 mg / L.

7. The Fe according to claim 1 3+ and Fe 2+ The synchronous test strip is characterized by, The second colorimetric area (4) consists of six color patches, corresponding to total iron concentrations of 500, 1000, 2000, 3000, 4000, and 5000 mg / L.

8. A Fe according to any one of claims 1 to 7 3+ and Fe 2+ The method for preparing synchronous test strips is characterized by, Potassium thiocyanate and a surfactant were dissolved in hydrochloric acid solution to prepare a first colorimetric solution. A portion of the test paper substrate was immersed in the first colorimetric solution and then vacuum dried to form a first colorimetric area (1) on the test paper substrate. Phenocyanide, ascorbic acid, and polyvinylpyrrolidone were dissolved in acetate buffer solution to prepare a second colorimetric solution. Another portion of the test paper substrate was immersed in the second colorimetric solution and then vacuum dried to form a second colorimetric area (2) on the test paper substrate, thus obtaining the Fe... 3+ and Fe 2+ Synchronous test strips.

9. A Fe according to claim 8 3+ and Fe 2+ The method for preparing synchronous test strips is characterized by, An isolation layer is provided on one side of the first color development area (1) and the second color development area (2) by hot pressing.

10. A Fe according to any one of claims 1 to 7 3+ and Fe 2+ Synchronous test strips for Fe in boiler chemical cleaning 3+ and Fe 2+ Applications in detection.

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