Method for detecting content of peroxydisulfate in copper acid etching solution

Abstract

The invention provides a method for detecting the content of peroxydisulfate in a copper acid etching solution, which comprises the following steps: sequentially adding an acid solution and a ferrite solution into the copper acid etching solution, uniformly mixing, titrating by using a potassium permanganate standard titration solution, and measuring the consumption volume V1; taking the acid solution and the ferrite solution with the same specification and volume as blank control, uniformly mixing, titrating by using the potassium permanganate standard titration solution, and measuring the consumption volume V0; the content of peroxydisulfate in the copper acid etching liquid can be calculated according to the difference value of V0 and V1. The method has the advantages that the reagent is simple and easy to obtain, the price is economical and practical, the test method is simple, the peroxydisulfate raw material is considered, the data stability and repeatability are high, the required instrument is simple and the cost is low, and the rapid and accurate detection of the peroxydisulfate content in the copper acid etching liquid can be realized.

Description

Technical Field

[0001] This invention relates to the field of chemical analysis technology, and in particular to a method for detecting the persulfate content in copper acid etching solution. Background Technology

[0002] The copper acid etching solution system is complex, containing high concentrations of copper ions, hydrogen ions, and various halide ions as impurities. Existing detection methods are easily affected by interference in this complex system, making it difficult to simultaneously ensure accuracy, ease of operation, and environmental friendliness. Therefore, developing a persulfate content detection method that is simple to obtain, easy to operate, low in detection cost, environmentally friendly, and applicable to the complex copper acid etching solution system has become an urgent technical problem to be solved in current industrial production. Since persulfate is a key oxidant for maintaining etching rate and uniformity, fluctuations in its concentration directly affect the etching quality and production yield of printed circuit boards (PCBs) or precision parts. Therefore, achieving rapid and accurate online or on-site monitoring of persulfate is of vital practical significance for optimizing process control, stabilizing product quality, reducing chemical consumption, and reducing pollution emissions.

[0003] Currently, the main methods for detecting disulfate content include ion chromatography, high performance liquid chromatography, iodometric titration, and fluorescence spectrometry. However, these methods have significant limitations when applied to complex etching solution systems.

[0004] While ion chromatography and high-performance liquid chromatography (HPLC) offer strong separation capabilities and high detection accuracy, the required instruments (such as HPLC systems) are expensive, typically costing hundreds of thousands of yuan per unit, and their daily operation and maintenance costs are also substantial. Furthermore, these methods involve cumbersome pretreatment, long analysis cycles, and require highly skilled operators; the large instruments are also difficult to move and deploy. Therefore, they are more suitable for offline precision analysis in laboratories and cannot meet the real-time, rapid, and convenient on-site detection needs of industrial production lines.

[0005] II. Iodometric titration is a commonly used traditional method in industrial settings. Its principle is based on the strong oxidizing property of persulfate to oxidize iodide ions to elemental iodine under acidic conditions. The resulting elemental iodine is then titrated with a standard sodium thiosulfate solution, thus indirectly calculating the persulfate content. However, this method has significant drawbacks: First, it requires multiple chemical reagents such as potassium iodide, starch indicator, and sodium thiosulfate, making the process complex. Second, the determination of the titration endpoint (fading of the blue color) relies on the operator's subjective experience and visual perception, making it prone to human error and resulting in poor reproducibility. Third, a small amount of toxic iodine vapor may be released during the reaction, posing a potential threat to the operator's health and potentially causing secondary pollution of the working environment, which is inconsistent with the development concept of green chemistry.

[0006] III. Fluorescence spectrophotometry quantifies fluorescence based on changes in fluorescence signals induced by the reaction of specific fluorescent probes with persulfate, theoretically offering the advantage of high sensitivity. However, this method faces significant challenges in practical applications: on the one hand, stable and specific fluorescent reagents are often difficult to synthesize, expensive, and may suffer from poor storage stability; on the other hand, and most critically, the high concentrations of copper ions (which have a fluorescence quenching effect) and complex matrix components such as chloride ions in the copper acid etching solution generate severe fluorescence interference, leading to decreased probe selectivity, distorted detection signals, and consequently, severely affecting the accuracy and reliability of the analytical results.

[0007] Therefore, this invention develops a detection strategy that aims to overcome the interference barriers of complex matrices and integrates multiple advantages such as speed, simplicity, low cost, and environmental friendliness, becoming a key technological breakthrough direction for promoting the refined control and green development of etching processes. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a method for detecting the persulfate content in copper acid etching solution, which solves the defects of existing persulfate detection methods such as expensive instruments, complicated operation, high reagent cost, easy generation of secondary pollution and poor anti-interference ability.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a method for detecting the persulfate content in a copper acid etching solution, the method comprising the following steps:

[0011] Add acid and ferrous salt solution to copper acid etching solution in sequence, mix well, and then titrate with potassium permanganate standard titration solution to determine the volume consumed as V1.

[0012] As a blank control, the same specifications and volumes of acid solution and ferrous salt solution were taken, mixed evenly, and titrated with the potassium permanganate standard titration solution to determine the volume consumed as V0.

[0013] The formula for calculating the persulfate content in the copper acid etching solution is as follows:

[0014]

[0015] C: Molar concentration;

[0016] M: Molecular weight;

[0017] m: Mass of copper acid etching solution.

[0018] This invention utilizes potentiometric titration to determine the persulfate content in copper acid etching solution. In an acidic solution, excess ferrous ammonium sulfate reacts with the persulfate in a redox reaction, reducing the Fe... 2+ Oxidized to Fe 3+ Excess ferrous ammonium sulfate reacts with potassium permanganate solution, while a blank is prepared simultaneously. This method has the advantages of readily available and inexpensive reagents, simple testing method that accommodates persulfate raw materials, high data stability and repeatability, and simple and low-cost instruments. It can achieve rapid and accurate detection of persulfate content in copper acid etching solution.

[0019] As a preferred embodiment of the present invention, the acid solution includes dilute sulfuric acid.

[0020] As a preferred technical solution of the present invention, the mass concentration of the acid solution is 1-5%, for example, it can be 1%, 2%, 3%, 4% or 5%, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] As a preferred technical solution of the present invention, the pH of the acid solution added to the endpoint is 0-3, for example, it can be 0, 1, 2 or 3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] As a preferred embodiment of the present invention, the ferrous salt solution includes ferrous ammonium sulfate solution.

[0023] As a preferred embodiment of the present invention, the concentration of the ferrous salt solution is 0.05-0.5 mol / L, for example, it can be 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] As a preferred technical solution of the present invention, the concentration of the potassium permanganate standard titration solution is 0.3-0.7 mol / L, for example, it can be 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L or 0.7 mol / L, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] As a preferred embodiment of the present invention, the molar ratio of ferrous ions in the ferrous salt solution to persulfate ions in the copper acid etching solution is greater than 2.

[0026] As a preferred technical solution of the present invention, the detected temperature is 15-30℃, for example, it can be 15℃, 17℃, 19℃, 21℃, 23℃, 25℃, 27℃, 29℃ or 30℃, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0027] As a preferred technical solution of the present invention, the detection shall be performed in parallel at least twice.

[0028] All reagents used in this invention are of superior purity.

[0029] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0030] (1) The reagents are simple and readily available, economical and affordable, and do not cause secondary environmental pollution;

[0031] (2) The test method is simple, and the data is stable and highly repeatable;

[0032] (3) The required instrument is a common automatic potentiometric titrator, which is simple and convenient to operate and has a wide range of applications;

[0033] (4) This method can also be used for the titration of persulfate raw materials. KMnO4 titration solution can also be used as a reagent for determining the hydrogen peroxide content in copper acid etching solution in hydrogen peroxide system and for determining persulfate raw materials. This unifies experimental reagents and reduces the time for switching solutions. Detailed Implementation

[0034] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0035] In one specific embodiment, the present invention provides a method for detecting the persulfate content in a copper acid etching solution, the method comprising the following steps:

[0036] Add dilute sulfuric acid (1-5% by mass) to the copper acid etching solution until the pH of the solution is 0-3, then add ferrous ammonium sulfate standard solution, mix well, and titrate with potassium permanganate standard titration solution, and record the volume consumed V1.

[0037] As a blank control, take the same specifications and volume of acid solution and ferrous ammonium sulfate solution as described above, mix them evenly, and titrate them with the potassium permanganate standard titration solution, and determine the volume consumed as V0.

[0038] The formula for calculating the persulfate content in the copper acid etching solution is as follows:

[0039]

[0040] C: Molar concentration;

[0041] M: Molecular weight;

[0042] m: Mass of copper acid etching solution.

[0043] It should be clarified that any use of the process provided in the embodiments of the present invention or any substitution or change of conventional data falls within the protection and disclosure scope of the present invention.

[0044] Example 1

[0045] This embodiment provides a method for detecting the persulfate content in a copper acid etching solution, the method comprising the following steps:

[0046] Add dilute sulfuric acid (3% by mass) to the copper acid etching solution until the solution pH < 1, then add 20 mL of 0.1 mol / L ferrous ammonium sulfate standard solution, mix well, pre-stir for 60 s, and titrate with 0.5 mol / L potassium permanganate standard titration solution. The stirring speed is 300 r / min and the titration speed is 2 mL / min. The volume consumed is V1.

[0047] As a blank control, take the same specifications and volume of acid solution and ferrous ammonium sulfate solution as described above, mix them evenly, and titrate them with the potassium permanganate standard titration solution, and determine the volume consumed as V0; perform three parallel experiments in the same way, and use ammonium persulfate standard solution as a sample to perform three tests in the same way.

[0048] The formula for calculating the persulfate content in the copper acid etching solution is as follows:

[0049]

[0050] C: Molar concentration;

[0051] M: Molecular weight;

[0052] m: Mass of copper acid etching solution.

[0053] Example 2

[0054] This embodiment provides a method for detecting the persulfate content in a copper acid etching solution, the method comprising the following steps:

[0055] Add dilute sulfuric acid (1% by mass) to the copper acid etching solution until the solution pH < 1, then add 20 mL of 0.1 mol / L ferrous ammonium sulfate standard solution, mix well, pre-stir for 30 s, and titrate with 0.5 mol / L potassium permanganate standard titration solution. The stirring speed is 300 r / min and the titration speed is 2 mL / min. The volume consumed is V1.

[0056] As a blank control, take the same specifications and volume of acid solution and ferrous salt solution as described above, mix them evenly, and titrate them with the potassium permanganate standard titration solution, and determine the volume consumed as V0; perform three parallel experiments in the same way, and use 99.5% sodium persulfate standard solution as a sample to perform three tests in the same way.

[0057] The formula for calculating the persulfate content in the copper acid etching solution is as follows:

[0058]

[0059] C: Molar concentration;

[0060] M: Molecular weight;

[0061] m: Mass of copper acid etching solution.

[0062] Example 3

[0063] This embodiment provides a method for detecting the persulfate content in a copper acid etching solution, the method comprising the following steps:

[0064] Add dilute sulfuric acid (5% by mass) to the copper acid etching solution until the solution pH < 1, then add 20 mL of 0.1 mol / L ferrous ammonium sulfate standard solution, mix well, pre-stir for 60 s, and titrate with 0.5 mol / L potassium permanganate standard titration solution. The stirring speed is 300 r / min and the titration speed is 1 mL / min. The volume consumed is measured as V1.

[0065] As a blank control, take the same specifications and volume of acid solution and ferrous ammonium sulfate solution as described above, mix them evenly, and titrate them with the potassium permanganate standard titration solution to determine the volume consumed as V0; perform three parallel experiments in the same way, and take a new set of copper acid etching solution as a sample to perform three tests in the same way.

[0066] The formula for calculating the persulfate content in the copper acid etching solution is as follows:

[0067]

[0068] C: Molar concentration;

[0069] M: Molecular weight;

[0070] m: Mass of copper acid etching solution.

[0071] Comparative Example 1

[0072] This comparative example provides a method for detecting the persulfate content in a copper acid etching solution. The difference between this method and Example 1 is that: after adding dilute sulfuric acid to the copper acid etching solution and mixing it evenly, the solution is directly titrated with a standard ferrous sulfate solution, and the volume consumed is recorded as V1. Titration with potassium permanganate standard solution and control test are not performed. All other aspects are the same as in Example 1.

[0073] Performance testing

[0074] The detection results of persulfate in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0075] Table 1

[0076]

[0077] In Table 1, " / " indicates that there is no relevant data.

[0078] As can be seen from Table 1, the present invention utilizes potentiometric titration to determine the content of persulfate in copper acid etching solution. The test method is simple, and the data is stable and highly repeatable.

[0079] A comprehensive comparison of Example 1 and Comparative Example 1 shows that the direct titration method of ferrous ammonium sulfate, due to its inherent defects, cannot accurately quantify the content of persulfate and can only be used as a theoretical research reference. In contrast, the back titration method of ferrous ammonium sulfate-potassium permanganate overcomes many shortcomings of the direct titration method, combining accuracy, practicality, and operability. It can efficiently and accurately determine the content of persulfate, providing a reliable and feasible technical solution for persulfate-related detection work, and has important practical application value and promotion significance.

[0080] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for detecting the persulfate content in a copper acid etching solution, characterized in that, The detection method includes the following steps: Add acid and ferrous salt solution to copper acid etching solution in sequence, mix well, and then titrate with potassium permanganate standard titration solution to determine the volume consumed as V1. As a blank control, the same specifications and volumes of acid solution and ferrous salt solution were taken, mixed evenly, and titrated with the potassium permanganate standard titration solution to determine the volume consumed as V0. The formula for calculating the persulfate content in the copper acid etching solution is as follows: C: Molar concentration; M: Molecular weight; m: Mass of copper acid etching solution.

2. The detection method according to claim 1, characterized in that, The acid solution includes dilute sulfuric acid.

3. The detection method according to claim 1 or 2, characterized in that, The mass concentration of the acid solution is 1-5%.

4. The detection method according to any one of claims 1 to 3, characterized in that, The acid solution is added until the final pH is 0-3.

5. The detection method according to any one of claims 1 to 4, characterized in that, The ferrous salt solution includes ferrous ammonium sulfate solution.

6. The detection method according to any one of claims 1 to 5, characterized in that, The concentration of the ferrous salt solution is 0.05-0.5 mol / L.

7. The detection method according to any one of claims 1 to 6, characterized in that, The concentration of the potassium permanganate standard titration solution is 0.3-0.7 mol / L.

8. The detection method according to any one of claims 1 to 7, characterized in that, The molar ratio of ferrous ions in the ferrous salt solution to persulfate ions in the copper acid etching solution is greater than 2.

9. The detection method according to any one of claims 1 to 8, characterized in that, The temperature to be detected is 15-30℃.

10. The detection method according to any one of claims 1 to 9, characterized in that, The test must be performed in parallel at least twice.

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