TWM496760U - Chemical oxygen demand inspection device - Google Patents

Description

Chemical oxygen demand detecting device 【0001】

This creation is about a chemical oxygen demand detection device, in particular, a detection device for detecting chemical oxygen demand using a photocatalytic reaction of a titanium dioxide nanotube array.

【0002】

The commonly used test standards for detecting water pollution are chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Generally, the chemical oxygen demand value can be used to estimate the biochemical oxygen demand. In short, the two principles It is used to detect the dissolved oxygen consumed by the oxidant or microorganisms to decompose the substances in the water to indicate the degree of organic pollution in the water. Traditionally, methods for detecting chemical oxygen demand include reflux method, titration method, potassium permanganate method, etc., and the above method is operated by adding an excessive amount of potassium dichromate or potassium permanganate to the sample for oxidation reaction, and then counter-titrating. The remaining potassium dichromate or potassium permanganate reverts to the oxygen demand equivalent to the oxidation reaction. Although the results are highly accurate, the method still has many unresolved disadvantages, such as:

[0003]

(1) The reaction and operation time is long, about 3~4 hours.

[0004]

(2) Mercury sulphate is added during the testing process, which will produce mercury-containing waste liquid, causing secondary pollution.

[0005]

(3) There are many disturbances during the test, such as sample pH, chloride ion, cyanide ion, hexavalent chromium ion, hydrogen peroxide, heavy metal and other toxic chemicals.

[0006]

(4) If the dissolved oxygen in the water sample is supersaturated, it will cause an error. Therefore, the temperature must be adjusted or moderately diluted before testing.

【0007】

Therefore, the traditional method cannot meet the requirements of industrial process production and environmental protection, so there is a need to develop a stable and reliable chemical oxygen demand rapid detection technology.

[0008]

In the prior art, a photoactive working electrode which is induced by photocatalytic reaction can be applied to sewage detection, and the principle is to irradiate an electrode having semiconductor characteristics by an ultraviolet light source, and to raise the semiconductor surface electron from a valence band to a valence band. The conduction band is such that it generates electrons and holes. Because the holes have a strong oxidation effect, the organic matter reacts chemically to generate a current flowing to the auxiliary electrode. Here, the steady current at a specific time during the reaction is measured, or the total current at the end of the reaction time is calculated to obtain a total charge number, and the total charge is measured as the quantitative data of oxygen in the compound decomposition water, and the analysis results are as follows:

【0009】

Q =∫idt = nFN = nFVC

[0010]

Where N = analyte Moiré,

[0011]

n = number of electrons transferred during photoelectrochemical degradation,

[0012]

F = Faraday constant,

[0013]

V = sample volume,

[0014]

C = analyte concentration.

[0015]

Assume that the oxidation of O ₂ is expressed as:

[0016]

That is, an oxygen molecule is equal to four electrons, and the above formula can be derived to be converted into:

[0017]

Equivalent oxygen concentration (mole/L) = Q/4FV

[0018]

The equivalent oxygen concentration of the sample can be expressed as

[0019]

COD (mg/L of O ₂ ) = (Q/4FV) x 32000

[0020]

The above detection device implies the nature of the working electrode, and the degree of electron and hole recombination, which determines the efficiency of the reaction rate. Among them, titanium dioxide has advantages such as strong oxidation ability, good chemical stability, light corrosion resistance, non-toxicity, and low cost. It is widely used in the fields of sewage treatment, water quality monitoring, air purification, etc. In the art of knowing, there are also different forms of titanium dioxide, which are used as reaction catalysts for detecting chemical oxygen content.

[0021]

However, the conventional detecting device uses a xenon lamp as an ultraviolet light source. In order to prevent the sample solution from being heated by infrared rays, an infrared filter and a light shutter are required for use, and the light source must be preheated before being operated, and then the light source is used to cover the light source. When the shutter is opened, the experimental operation is completed, which is inconvenient in a large number of detection processes, and the structure of the detecting device is complicated. Therefore, in practical use, there is an urgent need for a detection device that is easier to operate, has a more simplified structure, has a shorter detection time, and has a large detection limit.

[0022]

In view of the above-mentioned problems, the present invention proposes a chemical oxygen demand detecting device, which provides a device with a large detection limit, a short detection time, a simplified device structure, and a simple operation.

[0023]

Based on the above purposes, the present invention provides a chemical oxygen demand detecting device comprising a three-electrode module, a light source module, a sample tank, a fixed seat, an electrochemical control and measurement module, and an analysis module. The three-electrode module may comprise a titanium dioxide nanotube array electrode, an auxiliary electrode and a reference electrode, and the nanotube tube of the titanium dioxide nanotube array electrode has a length of between 1000 nm and 2500 nm. The light source module has a fixed separation distance from the titanium dioxide nanotube array electrode, and provides a single wavelength of light to excite the photocatalytic reaction of the titanium dioxide nanotube array electrode. The sample tank is used to hold the sample. The fixing seat is disposed around the sample slot for fixing the three-electrode module and the light source module to be immersed in the sample. The electrochemical control and measurement module can be electrically connected to the three-electrode module for applying a stable voltage to the electrode of the titanium dioxide nanotube array to cooperate with the working electrode of the light source module to generate photocatalysis, and to receive the three-electrode module. The current signal corresponding to the unit time. The analysis module integrates the current signal according to the time of the current signal to obtain the total charge amount, and estimates the chemical oxygen demand measurement result according to the total charge amount.

[0024]

Preferably, the nanotube diameter of the titanium dioxide nanotube array electrode may be about 1800 nm to 2300 nm.

[0025]

Preferably, the light source module may comprise an ultraviolet light emitting diode.

[0026]

Preferably, the single wavelength of the light source module is between 340 nm and 380 nm.

[0027]

Preferably, the light intensity of the light emitting module is between 10 mW/cm ² and 30 mW/cm ² .

[0028]

Preferably, the distance between the light source module and the titanium dioxide nanotube array electrode is between 0.5 cm and 2 cm.

[0029]

Preferably, the chemical oxygen demand detecting device of the present invention further comprises means for applying a stable voltage to the electrode of the titanium dioxide nanotube array, the voltage system being between 0V and 1V.

[0030]

Preferably, the chemical oxygen demand detecting device of the present invention further comprises a power source control and adjusting device for controlling the light intensity value of the light source module.

[0031]

Preferably, the titanium dioxide nanotube array electrode may be prepared by anodizing the titanium metal, and the electrolyte used in the anodizing method may comprise ammonium fluoride, hydrogen fluoride, glycerin or ethylene glycol.

[0032]

Preferably, the glycerol concentration is between 30% and 70% by weight.

[0033]

Preferably, the sample tank can comprise a batch reactor or a continuous flow reactor.

[0034]

The feature of this creation is superior to the prior art in that the detection device does not need a light shutter, a filter, and the time for turning on the ultraviolet light source is short, the detection device is cheaper, and the operation is relatively simple. Compared with the traditional detection method, chloride ion is well tolerated. Overcoming the traditional method, it is necessary to add mercury sulfate to inhibit chloride ions and reduce secondary pollution to the environment. Moreover, the detection result of the real sewage shows that no additional background value detection is needed in use, that is, the detection result is compared with the concentration of the calibration line, that is, the chemical oxygen demand.

[0085]

10‧‧‧Three-electrode module
11‧‧‧Titanium dioxide nanotube array electrode
12‧‧‧ reference electrode
13‧‧‧Auxiliary electrode
20‧‧‧UV light-emitting diode
30‧‧‧ Fixed seat
40‧‧‧ sample slot
50‧‧‧Electrochemical Control and Measurement Module
60‧‧‧Analysis module

[0035]

The first picture is a schematic diagram of the chemical oxygen demand detecting device of the present invention.

[0036]

Fig. 2 is a graph showing the concentration effect of the theoretical chemical oxygen demand of potassium hydrogen phthalate in the first experimental example of the present invention.

[0037]

Figure 3 is a concentration effect diagram of the theoretical chemical oxygen demand determination of oxalic acid in the second experimental example of the present invention.

[0038]

Figure 4 is a graph showing the time effect of the detection of theoretical chemical oxygen demand in the third experimental example of the creation of potassium phthalate.

[0039]

Fig. 5 is a time-effect diagram for detecting the theoretical chemical oxygen demand of the oxalic acid in the fourth experimental example of the present invention.

[0040]

Fig. 6 is a diagram showing the chloride effect of the theoretical chemical oxygen demand of the potassium hydrogen phthalate in the fifth experimental example of the present invention.

[0041]

Figure 7 is a diagram showing the chloride effect of the theoretical chemical oxygen demand for the determination of oxalic acid in the sixth experimental example of the present invention.

[0042]

Figure 8 is a comparison of the chemical oxygen demand rapid detection system and the closed potassium dichromate detection method in the seventh experimental example of the creation.

[0043]

In order to understand the characteristics, content and advantages of this creation and the effects that can be achieved by the examiner, the author will use the drawings in detail and explain the following in the form of the examples, and the schematics used therein are the subject of It is only for the purpose of illustration and supplementary instructions. It is not necessarily the true proportion and precise configuration after the implementation of the creation. Therefore, the proportions and configuration relationships of the attached drawings should not be interpreted or limited in the actual implementation scope.

[0044]

The preparation conditions of the titanium dioxide nanotube array electrode of the present invention are as follows: the titanium titanium plate is washed in an ultrasonic oscillator by acetone, isopropyl alcohol and deionized water for 10 minutes, and the titanium dioxide nanoparticle is produced by electrochemical anodization. The tube film, the cleaned titanium plate is used as the anode, the platinum plate is used as the cathode, and the immersion electrolyte is glycerin to water in a weight ratio of 6:4 to 8:2 and contains 0.3% to 1% by weight of ammonium fluoride. The electrolysis voltage is 10V~50V, the solution temperature is 10°C~50°C, the electrolysis time is 1 hour~4 hours, and then sintered at 600°C for 2 hours to 6 hours to obtain an array of titanium dioxide nanotubes with a tube length of about 1000 nm to 2500 nm. The ammonium fluoride of the electrolyte may be replaced by hydrogen fluoride, and the glycerin may be substituted with ethylene glycol, but the implementation is not limited thereto.

[0045]

Preferably, the immersion electrolyte has a weight ratio of glycerin to water of 6:4 and comprises 0.5% by weight of ammonium fluoride, an electrolytic voltage of 30 V, a solution temperature of 20 ° C, a plating time of 2 hours, and then sintering at 600 ° C. In an hour, an array of titanium dioxide nanotubes having a tube length of about 2100 nm was obtained.

[0046]

It has been confirmed by experiments that a structurally complete titanium dioxide nanotube array film can be produced when the weight ratio of glycerin to water is about 6:4 to 8:2. When the weight ratio of glycerol to water is 1:9, 2:8, 4:6, no structurally intact nanotubes are produced, because the ratio of glycerol to water affects the ion exchange rate and the chemical etching of fluoride ions The rate, which means controlling the current density during electroplating, is an important factor affecting the length of the nanotube tube. Therefore, when the water content is higher, the tube length is shorter or the structure is incomplete; when the water content is lower than a certain value, Then the nanotubes cannot be formed.

[0047]

Therefore, the TiO2 concentration of the inventive titanium dioxide nanotube array electrode can be from 30% to 70% by weight, and can be 40%, 50% or 60% by weight.

[0048]

The nanotube tube length of the titanium dioxide nanotube array electrode formed through the above preparation conditions may be from 1000 nm to 2500 nm, preferably from 1800 nm to 2300 nm. That is, the nanotube length formed using the above preparation conditions may be about 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, 2000 nm, 2100 nm, 2200 nm, 2300 nm, 2400 nm or 2500 nm.

[0049]

Please refer to Fig. 1, which is a schematic diagram of the chemical oxygen demand detecting device of the present invention. In the figure, a chemical oxygen demand detecting device may include a three-electrode module 10, an ultraviolet light emitting diode 20, a fixing base 30, a sample tank 40, an electrochemical control and measurement module 50, and an analysis module 60. The three-electrode module 10 can include a titanium dioxide nanotube array electrode 11, a reference electrode 12, and an auxiliary electrode 13, and the nanotube tube array electrode of the titanium dioxide nanotube array electrode 11 is between 1800 and 2500 nm.

[0050]

The titanium dioxide nanotube array electrode 11 can be made to generate stable electron and hole patterns by the ultraviolet light emitting diode 20 and the electrochemical control and measurement module 50. The ultraviolet light-emitting diode 20 used in the present invention is a single-wavelength light-emitting diode, and provides a light source having a wavelength of 365 nm. The ultraviolet light emitting diode 20 can be a miniature ultraviolet light emitting diode for providing stable light intensity, and the fixed distance from the titanium dioxide nanotube array electrode 11 is 0.8 cm to 1.5 cm, and the area of the irradiated titanium dioxide nanotube array electrode 11 is 0.785. The area of cm ² . The electrochemical control and measurement module 50 is electrically connected to the titanium dioxide nanotube array electrode 11 for applying a voltage to the titanium dioxide nanotube array electrode 11 to suppress recombination of electrons and holes.

[0051]

Compared with the xenon lamp, the use of the light-emitting diode light source has the advantages of quick start, full intensity output after opening, short opening time, no need to cover with a light shutter; small lamp, only a few watts of energy saving, and a single wavelength is not Filters are required to filter infrared light, which reduces the concern of infrared heating when detecting samples, and reduces the price of the detection device, which is relatively simple to operate.

[0052]

Titanium dioxide can be excited by a light source in the ultraviolet wavelength range to generate a stable electron and hole pattern, so that the wavelength of the single-wavelength ultraviolet light-emitting diode 20 can be in the linear range of 340 nm to 380 nm. The implementation may be a single wavelength of 340 nm, 345 nm, 350 nm, 355 nm, 360 nm, 365 nm, 370 nm, 375 nm or 380 nm.

[0053]

The ultraviolet light-emitting diode 20 used in the present invention provides that the light intensity of the light source is too strong or too weak to affect the detection efficiency, so the light intensity of the ultraviolet light-emitting diode 20 can be between 10 mW/cm ² and 30 mW. inner / cm ² of the linear range, may be ^{10mW / cm 2, 15mW / cm} 2, 20mW / cm 2, 25mW / cm 2 or 30mW / cm ² on the embodiment.

[0054]

Since the tube length or the tube diameter of the titanium dioxide nanotube array electrode 11 is different, and the distance between the light-emitting module and the titanium dioxide nanotube array electrode 11 is different, the photocurrent amount generated eventually is affected. In the experimental example of the present invention, the distance between the ultraviolet light emitting diode 20 and the titanium dioxide nanotube array electrode 11 may be in a linear range of 0.5 cm to 2 cm, and may be 0.5 cm, 0.8 cm, 0.9 cm, 1.0 cm, 1.2 cm, 1.5 cm or 2 cm.

[0055]

The electrochemical control and measurement module 50 provides a stable voltage to the titanium dioxide nanotube array electrode 11 to suppress the recombination of electrons and holes, and the voltage value can be between 0V and 1V, and can be implemented within the above voltage range. Within the linear range, it may include 0.1V, 0.2V, 0.3V, 0.4V, 0.5V, 0.6V, 0.7V, 0.8V, 0.9V or 1V.

[0056]

In practice, the light intensity of the light-emitting module, the distance between the light source module and the titanium dioxide nanotube array electrode 11 and the stable voltage supplied by the electrochemical control and measurement module 50 to the titanium dioxide nanotube array electrode 11 can be obtained according to The calibration curve in the good linear range is adjusted.

[0057]

The fixing base 30 can be an acid-resistant material, such as polypropylene or Teflon, and the fixing base 30 can fix the three-electrode module 10 and the ultraviolet light-emitting diode 20. The electrode for detecting the reaction is an immersion detecting device. The three-electrode module 10 is electrically connected to the electrochemical control and measuring module 50, and can receive the current signal corresponding to the three-electrode module for 10 unit time. The analysis module 60 integrates the current signal according to the time of the current signal to obtain the total charge amount, and estimates the chemical oxygen demand data according to the total charge amount.

[0058]

In practice, the sample tank 40 of the present chemical oxygen demand detecting device can be changed to a batch reactor or a continuous flow reactor as needed.

[0059]

Please refer to Fig. 2 and Fig. 3 for the determination of the theoretical chemical oxygen demand concentration of potassium phthalate in the first experimental example of this creation and the determination of oxalic acid in the second experimental example. The concentration effect diagram of the quantity. In the figure, potassium hydrogen phthalate and oxalic acid are used as standards, and the detection condition is that the titanium dioxide nanotube array electrode 11 and the ultraviolet light emitting diode 20 have a fixed distance of 1 cm and a light intensity of 20 mW/cm ² . The time is 50 seconds, the applied bias voltage is 0.1 V, the ordinate is the electric quantity (mAs), and the abscissa is the theoretical chemical oxygen demand concentration (mg/L) of the standard. The results showed that the theoretical COD concentration of potassium hydrogen phthalate and oxalic acid was 0.93 and 0.988 from 10 to 300 mg/L.

[0060]

The conditions for preparing the titanium dioxide nanotube array by anodizing method, in addition to the application of electrolytic voltage, electrolyte temperature, and electrolysis time, must simultaneously control the pH value and fluoride ion concentration of the electrolyte, and the titanium dioxide nanotube array of the present invention. The nanotube tube length is about 2100 nm and the tube diameter is about 180 nm. When titanium dioxide is used as a photocatalytic catalyst, it means that the titanium dioxide nanotube array has a longer tube length and can provide a larger reaction area, which helps Increase the detection range of chemical oxygen demand.

[0061]

Please refer to Fig. 4 and Fig. 5 for the determination of the theoretical chemical oxygen demand of the third experimental example of the present invention. The time effect diagram of the chemical oxygen demand and the theoretical chemistry of the determination of oxalic acid in the fourth experimental example. Time-effect map of the detection of oxygen demand. In the figure, potassium hydrogen phthalate and oxalic acid are used as standards, and the detection condition is that the titanium dioxide nanotube array electrode 11 and the ultraviolet light emitting diode 20 have a fixed distance of 1 cm and a light intensity of 20 mW/cm ² . The pressure is 0.4 V, the ordinate is the amount of electricity (mAs), and the abscissa is the theoretical chemical oxygen demand concentration (mg/L) of the standard. The results showed that the detection time of potassium hydrogen phthalate and oxalic acid was 10~50 seconds, and the linear relationship was between 0.991 and 0.995. This is because the rate of organic matter consumption and the original chemical oxygen demand were measured by photoelectrocatalysis at 10 seconds. The concentration is proportional, so the detection time can be 10 seconds in photoelectrocatalysis.

[0062]

The conventional detecting device uses a xenon lamp as an ultraviolet light source, and an ultraviolet filter and a light shutter are required for use. When the operation is performed, the light source must be turned on to preheat, and then the light shutter is used to cover the light source, and then the shutter is opened to complete the experimental operation. The operation flow is measured during the detection time, and the surface of the working electrode causes the reactant to oxidize, and the electrons originally separated from the working electrode are forced to move to the auxiliary electrode to generate a current, and the working electrode can be subjected to different photocatalytic reaction time. The total charge of the different total amounts is determined to be a better reaction completion time of about 45 seconds.

[0063]

The detection result of the creation shows that the balance can be reached within 10 seconds, and the total amount of electricity detected in the next 50 seconds increases with the unit time, which means that the sample can be uniformly contacted when reacting on the titanium dioxide nanotube array electrode 11. The surface of the electrode, and the reaction rate is proportional to the concentration of the original chemical oxygen demand, the proportional linearity of the different detection time between 10 and 50 seconds, and the proportional linearity of the samples with different oxidation rates of potassium hydrogen phthalate and oxalic acid It is not affected by the detection time, so providing a reaction time of 10 seconds can represent the concentration of chemical oxygen demand. The shorter detection time can also reduce the heating of the solution by the light source during sample detection, or other concerns about temperature changes.

[0064]

Please refer to Fig. 6 and Fig. 7 for the determination of potassium hydroxide phthalate in the fifth experimental example of the creation. The chloride effect diagram of the theoretical chemical oxygen demand and the theoretical chemical requirement for the determination of oxalic acid in the sixth experimental example. Chloride effect diagram of oxygen content. In the figure, potassium hydrogen phthalate and oxalic acid were used as standards. The theoretical COD concentration of the standard was 200 mg/L. After adjusting to pH 6, sodium chloride was added to the standard to adjust the chloride concentration. In the range of 400~800 mg/L, the detection condition is that the titanium dioxide nanotube array electrode 11 and the ultraviolet light emitting diode 20 have a fixed distance of 1 cm, a light intensity of 20 mW/cm ² , and a bias voltage of 0.4 V. The measurement time is 10 seconds, the abscissa is the chloride ion concentration (mg/L), and the ordinate is the electricity amount (mAs). The result shows that the detection of potassium hydrogen phthalate and the chloride ion concentration of oxalic acid is 800 mg/L. The values are 18.2% and 45.2%, while the error value of 600 mg/L is 4.5% and 5.5%. Regardless of potassium hydrogen phthalate or oxalic acid, in the case of chloride ions below 600 mg/L. Not easily interfered by chloride ions.

[0065]

Chloride ion is the largest interfering substance in traditional chemical oxygen demand detection by potassium dichromate. The traditional method is to add mercury sulfate to inhibit chloride ion, but mercury sulfate is easy to cause environmental pollution and has low chemical oxygen demand and chloride ion concentration. High water samples have a poor inhibitory effect. The test result of the chemical oxygen demand detecting device of the present invention shows that the chlorine ion tolerance is good compared with the conventional detection method, and the secondary pollution to the environment can be reduced.

[0066]

Please refer to Figure 8 for the comparison of the chemical oxygen demand rapid detection system of the seventh experimental example and the closed potassium dichromate method. The actual wastewater used in 8 different industries (steel industry, surface treatment) 15 samples of industry, paint factory, electroplating industry, chemical industry, paper mill, pharmaceutical factory, food industry), the detection conditions are titanium dioxide nanotube array electrode 11 and ultraviolet light emitting diode 20 fixed spacing of 1 cm, light The intensity is 20 mW/cm ² , the applied bias voltage is 0.4 V, the detection time is 10 seconds, the ordinate is the amount of electricity (mAs) detected by each sample, and the abscissa is the chemical oxygen demand detection concentration of the theoretical closed potassium dichromate method. (mg/L). The detection range of the chemical oxygen demand detection device of this creation is from the detection limit of 0.6 mg/L to the upper limit of correction of 300 mg/L.

[0067]

Table I

[0068]

Please also refer to Table 1 and Figure 8. The results show that when the real wastewater COD range is from 20 to 196 mg/L, the measured electricity can be measured by the chemical oxygen demand rapid detection system and the closed heavy chromium. The concentration measured by the potassium acid method is converted according to the following concentration correction formula to obtain the value of chemical oxygen demand:

[0069]

Electricity (mAs) = 0.03931 x potassium dichromate method (mg/L) + 9.12911

[0070]

Using the chemical oxygen demand rapid detection system of the present invention, the concentration calibration line can be estimated according to the above-mentioned detection of the chemical oxygen demand concentration of the real wastewater, and then the power of the blind sample water sample is converted to obtain the actual COD value, and the concentration is checked. The measuring line has a good linear relationship (R ² =0.997), so it is suitable for the detection of discharge water, process water and public water.

[0071]

In the traditional potassium dichromate method, an excessive amount of potassium dichromate is required to completely react with the organic matter, and then ammonium ferrous sulfate is added to reduce the remaining potassium dichromate to obtain COD data. The chemical oxygen demand detection device of this creation uses the pure water as the background value detection, and the current is less than 0.1%. The smaller background value can also reduce the noise signal, and the background value need not be considered in use. The effect, that is, the detection result can directly correspond to the concentration of chemical oxygen demand; furthermore, the detection signal is not affected by the background value, and the creation device can still detect the obvious current signal within a short detection time.

[0072]

Compared with the prior art, the detection result of the real waste water of the present invention is subtracted from the background value by the conventional technique, and the linear relationship between the data measured by the potassium dichromate method is 0.973. The scope of wastewater detection is also wide. It is inferred by the principle of photoelectrocatalysis detection that the result is a synergistic effect of adjusting the light intensity and voltage with the tube length of the titanium dioxide nanotube array electrode 11.

[0073]

In summary, the chemical oxygen demand rapid detection system of this creation has the following advantages compared with the prior art:

[0074]

In the prior art, the rapid detection method using the color of the drug package reaction often encounters incomplete reaction or interference of the hetero ions, which seriously affects the detection result.

[0075]

In the prior art, there is also a method of adding a chemical pack for heating reaction, and then using a spectrometer colorimetric detection method, but it is as time-consuming as the standard detection of potassium dichromate reflux heating method, and performing colorimetry after quantitatively adding the medicament. Compared with the final titration, the quantitative accuracy is low; compared with the creation, it takes hundreds of times and the accuracy is low.

[0076]

In the conventional technology, there is also a continuous monitoring method using multi-wavelength colorimetric, but it is susceptible to interference by impurities, and the lens and the optical path are easily damaged by the contamination of the waste material in the wastewater.

[0077]

In the prior art, there is also an automatic continuous monitoring device for the combined potassium dichromate method of the quantitative pump, the multi-directional switching valve and the photometer, but the quantitative pump and the multi-directional switching valve are easily blocked by the viscous material in the waste water, And it takes a long time to take the reflow heating.

[0078]

The surface of the photoelectrocatalytic electrode of the present invention is an oxidized organic substance with self-cleaning ability, and the substance in the waste water does not stick to the electrode, affecting the detection result, and the relative standard deviation of the detection of 900 standards for 30 consecutive days is 0.9%, and the surface structure of the electrode is not Change and damage.

[0079]

The photocatalytic technology used in this creation is an advanced oxidation method, and the reduction potential of the hydroxyl radical generated is as high as 2.80 volts, which is only after the 3.06 volts of fluoride ion, which is much higher than that of ozone, hydrogen peroxide, chlorine 2.07, 1.77, 1.36 volts. It has extremely high oxidizing power and can oxidize most of the organic matter in wastewater.

[0080]

In the prior art, the photocatalytic method is used to detect the photocurrent value of the wastewater sample corresponding to the chemical oxygen demand, but is affected by the photocatalytic generation of the electron hole pair, and the lower specific surface area of the photocatalyst nanoparticle is used. The diaphragm makes the photocatalytic photon efficiency low. If there is a component that is not easily oxidized in the wastewater, with the low, medium and high concentration wastewater, the oxidizing power of the hydroxyl radical is sufficient, but the concentration of the hydroxyl radical is insufficient, and the photocurrent value is easy to be at the medium and high chemical oxygen demand concentration. It tends to be fixed and cannot form a linear calibration curve.

[0081]

The photoelectrocatalysis used in this creation uses a low bias voltage to separate the electron hole generated by photocatalysis before compounding, and the high total surface area of the nanotube structure enables the hydrogen radical to be efficiently generated and maintain high oxidation capacity. With the amount of oxidation. Even if there are components in the wastewater that are not easily oxidized, the high concentration of hydroxyl radicals generated can still form a linear calibration curve with the photoelectric value of the low, medium and high chemical oxygen demand.

[0082]

This creation uses a light-emitting diode light source as a source of photocatalytic energy. The advantage is that it can be fully activated after being turned on and turned on. Because of its short opening time, it does not need to be covered by a light shutter when used; the lamp is small, only a few watts. It is energy-saving and has a single wavelength. It does not require filters to filter infrared light, which can reduce the concern of infrared heating when detecting samples, and reduce the price of the detection device. It is easy to operate.

[0083]

The advantages, features, and technical methods of the present invention will be more readily understood by referring to the exemplary embodiments and the accompanying drawings, and the present invention may be implemented in various forms and should not be construed as limited thereto. The embodiments set forth herein, and vice versa, will provide a more thorough and complete and complete disclosure of the scope of the present invention, and the present invention will only be The scope of the patent application is defined.

[0084]

The embodiments described above are only for explaining the technical idea and characteristics of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement them according to the scope of the patent. That is, the equivalent changes or modifications made by the people in accordance with the spirit revealed by this creation should still be covered by the scope of the patent of this creation.

10‧‧‧Three-electrode module

11‧‧‧Titanium dioxide nanotube array electrode

12‧‧‧ reference electrode

13‧‧‧Auxiliary electrode

20‧‧‧UV light-emitting diode

30‧‧‧ Fixed seat

40‧‧‧ sample slot

50‧‧‧Electrochemical Control and Measurement Module

60‧‧‧Analysis module

Claims (11)

[Item 1] A chemical oxygen demand detecting device comprising:
a three-electrode module comprising a titanium dioxide nanotube array electrode, an auxiliary electrode and a reference electrode, wherein the titanium nanotube array electrode has a length of between 1000 nm and 2500 nm;
a light source module is spaced apart from the electrode of the titanium dioxide nanotube array to provide a single wavelength light source for exciting the photocatalytic reaction of the titanium dioxide nanotube array electrode;
a sample tank for holding a sample;
a fixing seat is disposed around the sample slot, the fixing seat fixing the three-electrode module and the light source module to be immersed in the sample;
An electrochemical control and measurement module electrically connected to the three-electrode module for applying a voltage to the titanium dioxide nanotube array electrode to receive one of the unit time of the three-electrode module a current signal; and an analysis module electrically connected to the electrochemical control and measurement module, the current signal is integrated according to the current signal to obtain a total charge amount, and a total charge amount is calculated according to the total charge amount Chemical oxygen demand measurement results. [Item 2] The chemical oxygen demand detecting device of claim 1, wherein the light source module is an ultraviolet light emitting diode. [Item 3] The chemical oxygen demand detecting device of claim 1, wherein the single wavelength of the light source module is between 340 nm and 380 nm. [Item 4] For example, the chemical oxygen demand detecting device of claim 1 further includes a power source control and adjusting device for controlling the light intensity value of the light source module. [Item 5] The chemical oxygen demand detecting device according to claim 1, wherein the nanotube tube length is between 1800 nm and 2300 nm. [Item 6] The chemical oxygen demand detecting device of claim 1, wherein the voltage is between 0V and 1V. [Item 7] The chemical oxygen demand detecting device according to claim 1, wherein the light source module has a light intensity of 10 mW/cm ² to 30 mW/cm ² . [Item 8] For example, the chemical oxygen demand detecting device of claim 1 wherein the distance is between 0.5 cm and 2 cm. [Item 9] The chemical oxygen demand detecting device according to claim 1, wherein the titanium dioxide nanotube array electrode is made of titanium metal by anodization, and one of the anodizing methods comprises ammonium monofluoride. , hydrogen fluoride, monoglycerol or monoethylene glycol. [Item 10] The chemical oxygen demand detecting device of claim 9, wherein the glycerin concentration is between 40% and 60% by weight. [Item 11] The chemical oxygen demand detecting device of claim 1, wherein the sample tank comprises a batch reactor or a continuous flow reactor.