Device and method for measuring ion exchange capacity of ion exchange membrane

Abstract

A device for measuring the ion exchange capacity of an ion exchange membrane, according to one embodiment, comprises: an ionic conductivity change calculation unit which derives a first trend line and a second trend line for changes in ionic conductivity according to the reaction time of a titration solution formed by adding a titrant to a solution containing anions eluted from an ion exchange membrane, and which calculates each of a first boundary point at which the slope of the first trend line changes and a second boundary point at which the slope of the second trend line changes; a color information extraction unit for extracting color information of the titration solution at each fixed reaction time from an image showing changes in the color of the titration solution according to the reaction time; a color conversion point determination unit for extracting at least one conversion point on the basis of the extracted color information, and selecting, from the at least one conversion point, a conversion point between the first boundary point and the second boundary point on the basis of the reaction time and determining same as a color conversion point; and an ion exchange capacity calculation unit for calculating the ion exchange capacity of the ion exchange membrane at the color conversion point on the basis of the titration solution.

Description

Device and method for measuring ion exchange capacity of ion exchange membrane

[0001] The present invention relates to a device and method for measuring the ion exchange capacity of an ion exchange membrane, and more particularly, to a device and method for measuring the ion exchange capacity of an ion exchange membrane that measures objective ion exchange capacity by combining changes in ion conductivity and color changes.

[0002] Most existing methods for measuring ion exchange capacity rely solely on the silver titration method. Because the silver titration method is subjective and relies on human intuition, it's difficult to apply the measurement method across membrane manufacturers universally. In particular, when used in electrodialysis processes, a stable supply chain is essential through diversified membrane suppliers. However, the silver titration method suffers from the problem of being unable to be objectively and universally applied to calculate ion exchange membrane performance indicators.

[0003] One embodiment of the present invention provides an apparatus and method for measuring the ion exchange capacity of an ion exchange membrane, which calculates a final endpoint by combining the color transformation points generated by storing and digitizing the color change of an appropriate solution and an endpoint candidate group determined through an ion conductivity gradient as an image, and then measures the ion exchange capacity based on the image.

[0004] Among the embodiments, the device for measuring the ion exchange capacity of an ion exchange membrane includes: an ion conductivity change calculation unit that derives a first trend line and a second trend line for a change in ion conductivity according to a reaction time of a titration solution in which a titrant is added to a solution containing anions eluted from an ion exchange membrane, and calculates a first boundary point where a slope of the first trend line changes and a second boundary point where a slope of the second trend line changes, respectively; a color information extraction unit that extracts color information of the titration solution at regular reaction times from an image showing a color change of the titration solution according to the reaction time; a color change point determination unit that extracts at least one change point based on the extracted color information, and determines a change point between the first boundary point and the second boundary point based on the reaction time among the at least one change point as a color change point; and an ion exchange capacity calculation unit that calculates the ion exchange capacity of the ion exchange membrane based on the titration solution at the color change point.

[0005] The above ion conductivity change calculation unit may select, among a plurality of trend lines showing the ion conductivity change with respect to the reaction time, the one in which the reaction time of the first boundary point is calculated as the smallest value as the first trend line, and the one in which the reaction time of the second boundary point is calculated as the largest value as the second trend line.

[0006] The above ion conductivity change calculation unit determines the region between the first reaction time of the first boundary point and the second reaction time of the second boundary point as an endpoint region, and can extract a plurality of candidate endpoints having different reaction times within the endpoint region.

[0007] The above color information extraction unit can extract the color information including the converted RGB value for the color extracted from the image.

[0008] The above color information extraction unit can generate a graph representing the RGB values ​​for the above-described response time.

[0009] The above color transformation point determining unit can determine the point where the sign of the slope of the tangent line generated from the RGB values ​​of the predetermined reaction time in the graph changes as at least one transformation point.

[0010] The above color transformation point determining unit can determine a specific transformation point among the at least one transformation point that has the same reaction time as any one of the reaction times for each of the plurality of candidate endpoints as the color transformation point.

[0011] The above ion exchange capacity calculation unit can detect the ion conductivity and the capacity of the titrant at the reaction time corresponding to the color transformation point.

[0012] The above ion exchange capacity calculation unit can measure the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant at the reaction time corresponding to the color transformation point.

[0013] The above ion exchange capacity calculation unit can calculate the ion exchange capacity according to the mathematical formula below.

[0014] [Mathematical formula]

[0015] IEC = (C xfxa) / D

[0016] Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

[0017] Among the embodiments, a method for measuring the ion exchange capacity of an ion exchange membrane includes the steps of adding a titrant to a solution containing anions eluted from an ion exchange membrane and deriving a first trend line and a second trend line for a change in ionic conductivity of the titrant solution according to a reaction time, calculating a first boundary point where the slope of the first trend line changes and a second boundary point where the slope of the second trend line changes, respectively, extracting color information of the titrant solution at regular reaction times from an image showing a color change of the titrant solution according to the reaction time, extracting at least one transition point where the color of the titrant solution changes based on the extracted color information, selecting a transition point between the first boundary point and the second boundary point based on the reaction time from among the at least one transition point and determining it as a color transition point, and calculating the ion exchange capacity of the ion exchange membrane using the titrant solution at the color transition point.

[0018] The step of deriving the first trend line and the second trend line may further include the step of selecting, among a plurality of trend lines showing the change in the ionic conductivity with respect to the reaction time, the one in which the reaction time of the first boundary point is calculated as the smallest value as the first trend line, and selecting, as the second trend line, the one in which the reaction time of the second boundary point is calculated as the largest value as the second trend line.

[0019] The step of calculating the first boundary point and the second boundary point, respectively, may further include a step of determining an area between a first reaction time of the first boundary point and a second reaction time of the second boundary point as an endpoint area, and extracting a plurality of candidate endpoints having different reaction times within the endpoint area.

[0020] The step of extracting color information of the above-mentioned titration solution may further include a step of extracting the color information including converted RGB values ​​for the color extracted from the image.

[0021] The step of extracting color information of the above titration solution may further include a step of generating a graph representing the RGB values ​​for the above predetermined reaction time.

[0022] The step of extracting at least one transformation point may further include a step of determining a point where the sign of the slope of the tangent line generated from the RGB values ​​of the predetermined reaction time in the graph changes as the at least one transformation point.

[0023] The step of determining the color transition point may further include a step of determining a specific transition point having a reaction time equal to any one of the reaction times for each of the plurality of candidate endpoints among the at least one transition point as the color transition point.

[0024] The step of calculating the ion exchange capacity may further include a step of detecting the ionic conductivity of the titration solution and the capacity of the added titrant at the reaction time corresponding to the color transformation point.

[0025] The step of calculating the ion exchange capacity may further include a step in which the ion exchange capacity calculating unit measures the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant at a reaction time corresponding to the color change point.

[0026] The step of calculating the ion exchange capacity may further include a step of calculating the ion exchange capacity according to the following mathematical formula.

[0027] [Mathematical formula]

[0028] IEC = (C xfx A) / D

[0029] Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

[0030] The device and method for measuring the ion exchange capacity of an ion exchange membrane according to one embodiment of the present invention is objective and universally applicable because it combines the color transformation points generated by storing and digitizing the color change of the appropriate solution and the endpoint candidate group determined through the ion conductivity gradient as an image and calculates the final endpoint and measures the ion exchange capacity based on this.

[0031] The device and method for measuring the ion exchange capacity of an ion exchange membrane according to one embodiment of the present invention can accurately measure the ion exchange capacity of an anion exchange membrane by storing the color change of an appropriate solution as a video image, converting each image into an average color value, cross-combining it with images within a group of endpoint candidates, and calculating the final endpoint.

[0032] Figure 1 is a block diagram of an ion exchange capacity measuring device of an ion exchange membrane according to one embodiment of the present invention.

[0033] FIG. 2 is a flowchart showing steps for generating candidate endpoints of an endpoint region according to one embodiment of the present invention.

[0034] FIG. 3 is a flowchart showing steps for extracting color transformation points from an image according to one embodiment of the present invention.

[0035] FIG. 4 is a flowchart showing steps for calculating ion exchange capacity based on candidate endpoints and color transition points according to one embodiment of the present invention.

[0036] Figure 5 is a table showing changes in reaction time, amount of titrant added, and ionic conductivity according to one embodiment of the present invention.

[0037] Figure 6 is a graph showing the change in ionic conductivity of a titration solution according to reaction time according to one embodiment of the present invention.

[0038] Figure 7 is a graph of color information extracted from an image showing the color change of a titration solution according to reaction time according to one embodiment of the present invention.

[0039] FIG. 8 is a drawing for explaining a step of detecting a final endpoint according to one embodiment of the present invention.

[0040] FIG. 9 is a drawing for explaining a computing device according to one embodiment of the present invention.

[0041] The ion exchange capacity measuring device of an ion exchange membrane can measure the ion exchange capacity of the ion exchange membrane by using the capacity of the titrant added for the corresponding reaction time when any one of the candidate end points obtained based on the change in ion conductivity based on the reaction time overlaps with the color change point obtained based on the color change of the titrant solution.

[0042] Below, with reference to the attached drawings, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted for clarity of description, and similar parts are designated with similar reference numerals throughout the specification.

[0043] Throughout the specification and claims, whenever a part is referred to as "comprising" a component, this does not exclude other components, but rather includes other components, unless otherwise stated. Terms including ordinal numbers, such as "first," "second," etc., may be used to describe various components, but these components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0044] Terms such as “part,” “unit,” and “module” described in the specification may mean a unit capable of processing at least one function or operation described in the specification, which may be implemented by hardware or a circuit, software, or a combination of hardware or a circuit and software.

[0045] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0046] Figure 1 is a block diagram of an ion exchange capacity measuring device of an ion exchange membrane according to one embodiment of the present invention.

[0047] The ion exchange capacity measuring device (100) of an ion exchange membrane can measure the ion exchange capacity of the ion exchange membrane by using the capacity of the titrant added to the reaction time when one of the candidate end points obtained based on the change in ion conductivity based on the reaction time overlaps with the color change point obtained based on the color change of the titrant solution.

[0048] Referring to FIG. 1, an ion exchange capacity measuring device (100) of an ion exchange membrane may include an ion conductivity change calculation unit (110), a color information extraction unit (120), a color conversion point determination unit (130), and an ion exchange capacity calculation unit (140).

[0049] The ion conductivity change calculation unit (110) can derive a first trend line and a second trend line for the ion conductivity change according to the reaction time of a titration solution in which a titrant is added to a solution containing anions eluted from an ion exchange membrane.

[0050] For example, the titrant may be silver nitrate (AgNO3). The titrant solution may be a reaction solution in which the titrant is added to a solution containing an anion, which is the target solution, at regular reaction times.

[0051] Ionic conductivity can change each time a titrant is added to the titration solution. That is, ionic conductivity can vary over time.

[0052] The trend lines for the change in ionic conductivity according to the reaction time can be provided as multiple trend lines, including a first trend line and a second trend line. Various methods can be used to derive the trend lines, including the method of least squares, linear regression, polynomial regression, exponential smoothing, and moving average.

[0053] The ion conductivity change calculation unit (110) can calculate the first boundary point where the slope of the first trend line changes and the second boundary point where the slope of the second trend line changes.

[0054] The ion conductivity change calculation unit (110) can select, among a plurality of trend lines showing the ion conductivity change with respect to the reaction time, the one in which the reaction time of the first boundary point is calculated as the smallest value as the first trend line, and the one in which the reaction time of the second boundary point is calculated as the largest value as the second trend line.

[0055] The ion conductivity change calculation unit (110) can determine the region between the first reaction time of the first boundary point and the second reaction time of the second boundary point as the end point region.

[0056] The ionic conductivity change calculation unit (110) can extract multiple candidate endpoints having different reaction times within an endpoint region. Each of the multiple candidate endpoints can have different ionic conductivities and corresponding reaction times.

[0057] The color information extraction unit (120) can extract color information of the titration solution at regular reaction times from an image showing the color change of the titration solution according to the reaction time.

[0058] The color information extraction unit (120) can extract color information including converted RGB values ​​for colors extracted from an image.

[0059] The color information extraction unit (120) can generate a graph representing RGB values ​​for a certain reaction time.

[0060] The color conversion point determination unit (130) can extract at least one conversion point based on the extracted color information.

[0061] The color transformation point determination unit (130) can determine at least one transformation point as the point where the sign of the slope of the tangent line generated from each RGB value of a certain reaction time in the graph changes.

[0062] The color transformation point determination unit (130) can select a transformation point between the first boundary point and the second boundary point based on the reaction time from among at least one transformation point and determine it as a color transformation point.

[0063] The color transformation point determination unit (130) can determine a specific transformation point that has the same reaction time as any one of the reaction times for each of a plurality of candidate endpoints among at least one transformation point as the color transformation point.

[0064] The ion exchange capacity calculation unit (140) can calculate the ion exchange capacity of the ion exchange membrane based on the titration solution at the color change point. The ion exchange capacity calculation unit (140) can detect the ion conductivity and the titrant capacity at the reaction time corresponding to the color change point.

[0065] The ion exchange capacity calculation unit (140) can measure the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant at the reaction time corresponding to the color change point.

[0066] The ion exchange capacity calculation unit (140) can calculate the ion exchange capacity according to the mathematical formula below.

[0067] [Mathematical formula]

[0068] IEC = (C xfxa) / D

[0069] Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

[0070] FIG. 2 is a flowchart illustrating a step for calculating candidate endpoints in an endpoint region according to one embodiment of the present invention. The step for calculating candidate endpoints in an endpoint region of FIG. 2 may be performed using an ion exchange capacity measuring device (100) of an ion exchange membrane.

[0071] The ion exchange capacity measuring device (100) of an ion exchange membrane can add a titrant to a solution containing anions eluted from an ion exchange membrane and generate a graph of the change in ion conductivity of the titrant solution according to the reaction time (step S210).

[0072] The ion exchange capacity measuring device (100) of the ion exchange membrane can derive a first trend line and a second trend line for the change in ion conductivity according to the reaction time from the graph (step S220).

[0073] The ion exchange capacity measuring device (100) of the ion exchange membrane can calculate the first boundary point where the slope of the first trend line changes and the second boundary point where the slope of the second trend line changes (step S230).

[0074] The ion exchange capacity measuring device (100) of the ion exchange membrane can select, among a plurality of trend lines showing the change in ion conductivity with respect to the reaction time, the one in which the reaction time of the first boundary point is calculated as the smallest value as the first trend line, and the one in which the reaction time of the second boundary point is calculated as the largest value as the second trend line.

[0075] The ion exchange capacity measuring device (100) of an ion exchange membrane determines the region between the first reaction time corresponding to the first boundary point and the second reaction time corresponding to the second boundary point as an endpoint region, and can extract a plurality of candidate endpoints, each having a different reaction time, within the endpoint region (step S240).

[0076] FIG. 3 is a flowchart illustrating a step of extracting a color transition point from an image according to one embodiment of the present invention. The step of extracting a color transition point from the image of FIG. 3 may be performed using an ion exchange capacity measuring device (100) of an ion exchange membrane.

[0077] The ion exchange capacity measuring device (100) of an ion exchange membrane can add a titrant to a solution containing anions eluted from the ion exchange membrane and generate an image showing the color change of the titrant solution according to the reaction time (step S310).

[0078] For example, the ion exchange capacity measuring device (100) of the ion exchange membrane can generate a video image that captures the color change of the titration solution during the reaction time.

[0079] The ion exchange capacity measuring device (100) of the ion exchange membrane can convert the color extracted from the image into RGB values ​​(step S320).

[0080] For example, the ion exchange capacity measuring device (100) of the ion exchange membrane can extract a certain portion of an image, extract a color, and convert the extracted color into an RGB value.

[0081] The ion exchange capacity measuring device (100) of the ion exchange membrane can generate a graph showing RGB values ​​for the reaction time (step S330).

[0082] For example, the ion exchange capacity measuring device (100) of the ion exchange membrane can generate a graph representing RGB values ​​of an image of a titration solution according to a reaction time as coordinates.

[0083] The ion exchange capacity measuring device (100) of the ion exchange membrane can extract at least one conversion point where the color of the titration solution changes based on the RGB value for the reaction time (step S340).

[0084] For example, the ion exchange capacity measuring device (100) of an ion exchange membrane can extract at least one transformation point where the RGB value changes rapidly based on a graph generated as coordinates for the RGB value.

[0085] The ion exchange capacity measuring device (100) of an ion exchange membrane can extract a tangent line of a graph from RGB values ​​for a certain reaction time and determine the point where the sign of the slope of the extracted tangent line changes as a transformation point.

[0086] The ion exchange capacity measuring device (100) of the ion exchange membrane can select a conversion point between the first boundary point and the second boundary point based on the reaction time among at least one conversion point and determine it as a color conversion point (step S350).

[0087] The ion exchange capacity measuring device (100) of the ion exchange membrane can determine a specific conversion point having the same reaction time as any one of the reaction times for each of a plurality of candidate end points among at least one conversion point as a color conversion point.

[0088] Figure 4 is a flowchart illustrating steps for calculating ion exchange capacity based on candidate endpoints and color transition points according to one embodiment of the present invention. The step of calculating ion exchange capacity in Figure 4 can be performed using an ion exchange capacity measuring device (100) of an ion exchange membrane.

[0089] The ion exchange capacity measuring device (100) of the ion exchange membrane can extract the reaction time for each of a plurality of candidate endpoints within the endpoint region (step S410).

[0090] The ion exchange capacity measuring device (100) of the ion exchange membrane can extract the reaction time of the color change point (step S420).

[0091] The ion exchange capacity measuring device (100) of the ion exchange membrane can determine a specific candidate endpoint among a plurality of candidate endpoints whose reaction time is the same as the reaction time of the color change point as the final endpoint (step S430).

[0092] The ion exchange capacity measuring device (100) of the ion exchange membrane can calculate the ion exchange capacity based on the capacity of the titrant added to the titration solution at the final endpoint (step S440).

[0093] The ion exchange capacity measuring device (100) of the ion exchange membrane can detect the ion conductivity of the titrant solution and the capacity of the added titrant at the reaction time corresponding to the color change point.

[0094] The ion exchange capacity measuring device (100) of an ion exchange membrane can measure the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant (AgNO3) at the reaction time corresponding to the color change point.

[0095] The ion exchange capacity measuring device (100) of the ion exchange membrane can calculate the ion exchange capacity according to the mathematical formula below.

[0096] [Mathematical formula]

[0097] IEC = (C xfx A) / D

[0098] Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

[0099] Figure 5 is a table showing changes in reaction time, amount of titrant added, and ionic conductivity according to one embodiment of the present invention.

[0100] Referring to the table in Figure 5, the titration solution may include 0.1 M sodium hydroxide (NaOH) and 5% potassium chromate (K2CrO4) initially added. The sodium hydroxide may be included for ion elution, and the potassium chromate may be included as an indicator.

[0101] After this, 0.1 M silver nitrate (AgNO3) can be added to the titration solution in a volume of 0.1 mol to 0.4 mol at regular intervals. For example, silver nitrate can be added to the titration solution at a volume of about 0.2 mol every 2 minutes from the 16th to the 28th minute of the reaction time. Silver nitrate can be added to the titration solution at a volume of about 0.1 mol every minute from the 29th to the 43rd minute of the reaction time.

[0102] Referring to the table in Figure 5, the ionic conductivity of the titration solution can be determined according to the additional amount of silver nitrate added at each reaction time. The ionic conductivity can gradually change with each reaction time, from 19.01 at the beginning to 18.52 at 43 minutes of reaction time.

[0103] For example, at 32 minutes of reaction time, the additional amount of silver nitrate is 4.2 ml and the ionic conductivity is 18.58. At 34 minutes of reaction time, the additional amount of silver nitrate is 4.4 ml and the ionic conductivity is 18.55.

[0104] Figure 6 is a graph showing the change in ionic conductivity of a titration solution according to reaction time according to one embodiment of the present invention.

[0105] In Fig. 6, the graph shows a first trend line (TL1, trend line 1) and a second trend line (TL2, trend line 2) showing changes in ionic conductivity according to reaction time. The first trend line (TL1) includes the first boundary point (BP1) of the first reaction time (RT1). The second trend line (TL2) includes the second boundary point (BP2) of the second reaction time (RT2).

[0106] The first boundary point (BP1, boundary point1) can define the boundary between the first region and the endpoint region. The second boundary point (BP2, boundary point2) can define the boundary between the second region and the endpoint region.

[0107] The first region is the region for the reaction time for the anions eluted from the ion exchange membrane to react with silver nitrate. The second region is the region for the reaction time for the silver nitrate to react with the indicator. The endpoint region is the region that includes the endpoint at which the reaction between the eluted anions and silver nitrate is completed. The endpoint region is defined as the reaction time interval between the first reaction time (RT1) and the second reaction time (RT2) and may include multiple candidate endpoints (CEPs).

[0108] For example, in the table of FIG. 6, the ionic conductivity of the first boundary point (BP1) may be 18.64, the first reaction time (RT1, reaction time1) may be 26 minutes, and the volume of the added titrant, silver nitrate, may be 3.6 ml. The ionic conductivity of the second boundary point (BP2) may be 18.55, the second reaction time (RT2, reaction time2) may be 35 minutes, and the volume of the added titrant, silver nitrate, may be 4.5 ml.

[0109] The endpoint region may correspond to a reaction time between 26 and 35 minutes. Therefore, there may be nine candidate endpoints (CEPs), including the first boundary point (BP1) and the second boundary point (BP2). The candidate endpoints (CEPs) shown in the graph in Figure 6 are just one example.

[0110] Figure 7 is a graph of color information extracted from an image showing the color change of a titration solution according to reaction time according to one embodiment of the present invention.

[0111] The ion exchange capacity measuring device (100) of the ion exchange membrane can detect color from an image of a titration solution whose color changes during a reaction time and extract color information including RGB values ​​from the detected color.

[0112] The photos in Figure 7 show the titration solutions at each of the reaction times T1, T2, T3, and T4. The color of the titration solutions changes slightly at each of T1, T2, T3, and T4, but it is difficult to distinguish them with the naked eye. For example, T1 may correspond to 31 minutes, T2 to 32 minutes, T3 to 34 minutes, and T4 to 35 minutes.

[0113] For example, the ion exchange capacity measuring device (100) of an ion exchange membrane can detect a color by extracting a specific area (AA) of the image of the titration solution from each of T1, T2, T3, and T4. The ion exchange capacity measuring device (100) of an ion exchange membrane can convert the detected color into an RGB value. The RGB value can be expressed as a coordinate. The ion exchange capacity measuring device (100) of an ion exchange membrane can generate a graph using the RGB coordinates. The graph is generated using the RGB coordinate values ​​according to the reaction time.

[0114] In the graph (GRP), the reaction time can be defined as T0 to Tn. There are two points where the sign of the slope of the tangent line in the graph (GRP) changes: Tx and Tz. The points where the sign of the slope of the tangent line in the graph (GRP) changes can correspond to the turning points.

[0115] Both Tx and Tz correspond to transition points. For example, Tx could be the RGB coordinates corresponding to the 33-minute reaction time between T2 and T3. Tz could correspond to the reaction time 26 minutes prior.

[0116] Either Tx or Tz can ultimately be determined as the color transition point (CTP). The color transition point (CTP), where the color of the titrant solution changes, can correspond to the end point where the reaction between the titrant and the anion in the solution is completed.

[0117] FIG. 8 is a diagram illustrating a step of detecting a final endpoint according to one embodiment of the present invention. This is described with reference to FIGS. 6 and 7.

[0118] In Fig. 8, the first area (AR1, area1) and the end point area (EAR, end point area) can be distinguished through the first boundary point (BP1). The first area (AR1) shows the ionic conductivity during the reaction time during which the titrant and the anions in the solution eluted from the ion exchange membrane react.

[0119] The second area (AR2, area2) and the end point area (EAR) can be distinguished by the second boundary point (BP2). The second area (AR2) represents the ionic conductivity during the reaction time during which the titrant and indicator react.

[0120] The endpoint area (EAR) is a region encompassing multiple candidate endpoints where the reaction between an anion and an indicator in a solution is complete. The endpoint area (EAR) corresponds to the reaction time between the first threshold point (BP1) and the second threshold point (BP2). Each of the multiple candidate endpoints can correspond to a reaction time between 26 and 35 minutes. In other words, each of the multiple candidate endpoints can be determined by an additional titrant amount between 3.6 and 4.5 ml.

[0121] The first boundary point (BP1) and the second boundary point (BP2) were obtained from the trend lines of the change in ionic conductivity according to the reaction time in Fig. 6.

[0122] In Fig. 7, any one of the transformation points of Tx and Tz obtained from the graph (GRP) for RGB coordinates according to reaction time may correspond to the color transformation point (CTP) at which the color of the titration solution changes.

[0123] The ion exchange capacity measuring device (100) of the ion exchange membrane can determine one of a plurality of candidate endpoints in the endpoint area (EAR) as the final endpoint (EP).

[0124] The ion exchange capacity measuring device (100) of an ion exchange membrane can determine one conversion point that overlaps with a plurality of candidate endpoints among a plurality of conversion points (Tx, Tz) as a color conversion point (CTP). The ion exchange capacity measuring device (100) of an ion exchange membrane can determine the color conversion point (CTP) as a final endpoint (EP).

[0125] The reaction time of Tx is 33 minutes, and the reaction time coincides with one of the candidate endpoints between the first boundary point (BP1) and the second boundary point (BP2). Therefore, the ion exchange capacity measuring device (100) of the ion exchange membrane can determine Tx as the color transformation point (CTP) and judge it as the final endpoint (EP).

[0126] The ion exchange capacity measuring device (100) of an ion exchange membrane can measure the ion exchange capacity of an ion exchange membrane with 4.3 ml, which is the additional amount of titrant for the final end point (EP).

[0127] The ion exchange capacity measuring device (100) of the ion exchange membrane can measure the ion exchange capacity according to the mathematical formula below.

[0128] [Mathematical formula]

[0129] IEC = (C xfxa) / D

[0130] Here, IEC is the ion exchange capacity of the ion exchange membrane (mmol / g), C is the concentration of the titrant (mol / L), f is a factor indicating the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

[0131] For example, when C is 0.1 mol / L, f is 1, and D is 0.236 g, and the volume of the final endpoint titrant is 4.3 ml, the ion exchange capacity of the ion exchange membrane can be 1.82 mmol / g.

[0132] The ion exchange capacity measuring device (100) of an ion exchange membrane can check the ion exchange capacity calculation range for candidate endpoints within the endpoint region between the first boundary point (BP1) and the second boundary point (BP2). At the first boundary point (BP1), the titrant volume is 3.6 ml and the ion exchange capacity is 1.52 mmol / g. At the second boundary point (BP2), the titrant volume is 4.5 ml and the ion exchange capacity is 1.91 mmol / g. That is, the final ion exchange capacity according to the final endpoint determination can be determined within the range of 1.52 mmol / g to 1.91 mmol / g.

[0133] The ion exchange capacity measuring device (100) of the ion exchange membrane determines the final end point (EP) when the color change point (CTP) is detected through the graph of FIG. 6 and the graphs (GRP) of FIG. 7 and FIG. 8, and based on this, calculates 1.82 mmol / g as the optimal ion exchange capacity within the range of 1.52 mmol / g to 1.91 mmol / g, thereby increasing the degree of consistency.

[0134] Referring to FIG. 9, the device and method for measuring the ion exchange capacity of an ion exchange membrane according to embodiments can be implemented using a computing device (900).

[0135] The computing device (900) may include at least one of a processor (910), a memory (930), a user interface input device (940), a user interface output device (950), and a storage device (560) that communicate via a bus (920). The computing device (900) may also include a network interface (970) electrically connected to a network (90). The network interface (970) may transmit or receive signals to or from other entities via the network (90).

[0136] The processor (910) may be implemented in various types such as an MCU (Micro Controller Unit), an AP (Application Processor), a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an NPU (Neural Processing Unit), etc., and may be any semiconductor device that executes instructions stored in a memory (930) or a storage device (960). The processor (910) may be configured to implement the functions and methods described above with respect to FIGS. 1 to 8.

[0137] The memory (930) and storage device (960) may include various types of volatile or non-volatile storage media. For example, the memory may include read-only memory (ROM) (931) and random access memory (RAM) (932). In the present embodiment, the memory (930) may be located inside or outside the processor (910), and the memory (930) may be connected to the processor (910) via various known means.

[0138] In some embodiments, at least some of the components or functions of the ion exchange capacity measuring device and method of the ion exchange membrane according to the embodiments may be implemented as a program or software running on a computing device (900), and the program or software may be stored on a computer-readable medium.

[0139] In some embodiments, at least some of the components or functions of the ion exchange capacity measuring device and method of the ion exchange membrane according to the embodiments may be implemented using hardware or circuitry of the computing device (900), or may be implemented as separate hardware or circuitry that can be electrically connected to the computing device (900).

[0140] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by a person of ordinary skill in the art to which the present invention pertains using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0141] The device and method for measuring the ion exchange capacity of an ion exchange membrane according to one embodiment of the present invention combines the color transformation points generated by storing and digitizing the color change of the appropriate solution and the endpoint candidate group determined through the ion conductivity gradient as an image, and calculates the final endpoint, and measures the ion exchange capacity based on this, so that it has industrial applicability.

Claims

1. An ion conductivity change calculating unit that derives a first trend line and a second trend line for the change in ion conductivity according to the reaction time of a titration solution in which a titrant is added to a solution containing anions eluted from an ion exchange membrane, and calculates a first boundary point where the slope of the first trend line changes and a second boundary point where the slope of the second trend line changes, respectively; A color information extraction unit that extracts color information of the titration solution at regular reaction times from an image showing the color change of the titration solution according to the reaction time; A color conversion point determination unit that extracts at least one conversion point based on the extracted color information, and selects a conversion point between the first boundary point and the second boundary point based on the reaction time among the at least one conversion point and determines it as a color conversion point; and An ion exchange capacity measuring device of an ion exchange membrane, comprising an ion exchange capacity calculating unit for calculating the ion exchange capacity of the ion exchange membrane based on an appropriate solution at the color transformation point.

2. In paragraph 1, The above ion conductivity change calculation unit is one of a plurality of trend lines showing the ion conductivity change with respect to the reaction time. The first trend line is selected as the one for which the reaction time of the first boundary point is calculated to be the smallest value, An ion exchange capacity measuring device of an ion exchange membrane, wherein the reaction time of the second boundary point is calculated as the largest value, and is selected as the second trend line.

3. In paragraph 1, The above ion conductivity change calculating unit determines the region between the first reaction time of the first boundary point and the second reaction time of the second boundary point as an endpoint region, and extracts a plurality of candidate endpoints having different reaction times within the endpoint region. An ion exchange capacity measuring device of an ion exchange membrane.

4. In paragraph 1, The above color information extraction unit is an ion exchange capacity measuring device of an ion exchange membrane that extracts the color information including the converted RGB values ​​for the color extracted from the image.

5. In paragraph 4, The above color information extraction unit is an ion exchange capacity measuring device of an ion exchange membrane that generates a graph representing the RGB values ​​for the above predetermined reaction time.

6. In paragraph 5, The above color conversion point determining unit is an ion exchange capacity measuring device of an ion exchange membrane, wherein the point where the sign of the slope of the tangent line generated from the RGB values ​​of the predetermined reaction time in the graph changes is determined as at least one conversion point.

7. In paragraph 3, The above color conversion point determining unit is an ion exchange capacity measuring device of an ion exchange membrane, which determines a specific conversion point having a reaction time equal to any one of the reaction times for each of the plurality of candidate endpoints among the at least one conversion point as the color conversion point.

8. In paragraph 1, The above ion exchange capacity calculation unit is an ion exchange capacity measuring device of an ion exchange membrane that detects the ion conductivity and the capacity of the titrant at the reaction time corresponding to the color transformation point.

9. In paragraph 8, The above ion exchange capacity calculation unit is an ion exchange capacity measuring device of an ion exchange membrane that measures the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant at the reaction time corresponding to the color transformation point.

10. In paragraph 9, The above ion exchange capacity calculation unit is an ion exchange capacity measuring device of an ion exchange membrane that calculates the ion exchange capacity according to the following mathematical formula: [Mathematical formula] IEC = (C x f x a) / D Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

11. A step of adding a titrant to a solution containing anions eluted from an ion exchange membrane and deriving a first trend line and a second trend line for changes in the ion conductivity of the titrant solution according to the reaction time; A step of calculating a first boundary point at which the slope of the first trend line changes and a second boundary point at which the slope of the second trend line changes, respectively; A step of extracting color information of the titration solution at regular reaction times from an image showing the color change of the titration solution according to the reaction time; A step of extracting at least one transformation point at which the color of the titration solution is transformed based on the extracted color information; A step of selecting a transition point between the first boundary point and the second boundary point based on the reaction time among at least one transition point and determining it as a color transition point; and A method for measuring the ion exchange capacity of an ion exchange membrane, comprising the step of calculating the ion exchange capacity of the ion exchange membrane using a titration solution at the color transformation point.

12. In paragraph 11, The steps for deriving the first and second trend lines are as follows: Among the multiple trend lines showing the change in ionic conductivity with respect to the above reaction time, The first trend line is selected as the one for which the reaction time of the first boundary point is calculated to be the smallest value, A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising the step of selecting, as the second trend line, the value at which the reaction time of the second boundary point is calculated to have the largest value.

13. In paragraph 11, The step of calculating the first boundary point and the second boundary point, respectively, is as follows: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising the step of determining a region between a first reaction time of the first boundary point and a second reaction time of the second boundary point as an endpoint region, and extracting a plurality of candidate endpoints having different reaction times within the endpoint region.

14. In paragraph 11, The step of extracting the color information of the above titration solution is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising a step of extracting color information including converted RGB values ​​for colors extracted from the image.

15. In paragraph 14, The step of extracting the color information of the above titration solution is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising the step of generating a graph representing the RGB values ​​for the above-mentioned predetermined reaction time.

16. In paragraph 15, The step of extracting at least one transformation point is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising the step of determining a point at which the sign of the slope of the tangent line generated from the RGB values ​​of the predetermined reaction time in the graph changes as at least one conversion point.

17. In paragraph 13, The step of determining the color conversion point above is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising the step of determining a specific conversion point having a reaction time equal to any one of the reaction times for each of the plurality of candidate endpoints among the at least one conversion point as the color conversion point.

18. In paragraph 11, The step of calculating the above ion exchange capacity is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising a step of detecting the ion conductivity of the titration solution and the capacity of the added titrant at a reaction time corresponding to the color transformation point.

19. In Article 18, The step of calculating the above ion exchange capacity is: A method for measuring the ion exchange capacity of an ion exchange membrane, wherein the ion exchange capacity calculation unit further includes a step of measuring the ion exchange capacity of the ion exchange membrane based on the capacity of the titrant at a reaction time corresponding to the color transformation point.

20. In paragraph 19, The step of calculating the above ion exchange capacity is: A method for measuring the ion exchange capacity of an ion exchange membrane, further comprising a step of calculating the ion exchange capacity according to the following mathematical formula: [Mathematical formula] IEC = (C xfx A) / D Here, IEC is the ion exchange capacity of the ion exchange membrane, C is the concentration of the titrant (mol / L), f is a factor representing the total number of exchangeable anions for 1 mol of ions of the titrant, A is the volume of the titrant (ml), and D is the dry weight of the ion exchange membrane (g).

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