WO2020248542A1 - 一种基于电化学原理的余氯传感器及其用途 - Google Patents

一种基于电化学原理的余氯传感器及其用途 Download PDF

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Publication number
WO2020248542A1
WO2020248542A1 PCT/CN2019/123324 CN2019123324W WO2020248542A1 WO 2020248542 A1 WO2020248542 A1 WO 2020248542A1 CN 2019123324 W CN2019123324 W CN 2019123324W WO 2020248542 A1 WO2020248542 A1 WO 2020248542A1
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Prior art keywords
electrode
residual chlorine
metal silicide
chlorine sensor
silicide
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PCT/CN2019/123324
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English (en)
French (fr)
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张志峰
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成都万众壹芯生物科技有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/30—Electrodes, e.g. test electrodes; Half-cells
    • G01N27/307—Disposable laminated or multilayered electrodes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/48—Systems using polarography, i.e. measuring changes in current under a slowly-varying voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/10—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using catalysis

Definitions

  • the invention belongs to the technical field of sensors, and specifically relates to a residual chlorine sensor based on electrochemical principles and its use.
  • DPD N.N-diethyl-p-phenylenediamine
  • the principle of DPD spectrophotometry is that DPD reacts rapidly with free residual chlorine in water to produce a red compound. At a wavelength of 515nm, the absorbance is measured by spectrophotometry to determine residual chlorine.
  • the spectrophotometric method is complicated in operation, poor real-time detection, and the presence of multiple substances (such as manganese oxide, bromine, potassium iodide, copper, etc.) in the water will interfere with the results of residual chlorine detection. In addition, the reagent itself is easily discolored. The residual chlorine measurement results are unstable and the accuracy is low.
  • the electrochemical method uses sensors based on electrochemical principles to detect residual chlorine.
  • the electrodes of the sensors used for residual chlorine detection are generally metal (such as platinum) or metal alloy electrodes.
  • the electrode is easy to age, and it cannot achieve long-term stable detection of residual chlorine.
  • the electrode must be replaced frequently, resulting in very high cost of use and use This caused a lot of inconvenience. Thirty years have passed since the problem was discovered, but related problems have not yet been effectively resolved. In addition, the existing electrodes are difficult to achieve mass production, and the raw material costs are also high.
  • the purpose of the present invention is to provide an improved residual chlorine sensor and its application in order to overcome the shortcomings of the residual chlorine sensor based on electrochemical principles in the prior art.
  • a residual chlorine sensor based on electrochemical principles includes a working circuit and a plurality of electrodes. At least one of the plurality of electrodes adopts an electrode material including metal silicide.
  • the electrode material used for the working electrode and/or the counter electrode includes metal silicide.
  • the electrode material used for at least one of the plurality of electrodes is a two-layer structure or a three-layer structure.
  • one of the electrodes is composed of the metal silicide, and the other The layer is composed of silicon;
  • the middle layer is composed of silicon, and the outer layers on both sides of the middle layer are composed of the metal silicide.
  • the thickness of the layer made of metal silicide is 10 to 500 nanometers, and the thickness of the layer made of silicon is 0.1 to 1.5 millimeters.
  • the two-layer structure or the three-layer structure is formed by using a silicon substrate as a substrate, depositing a metal layer, and then performing heat treatment.
  • the deposition method used for the deposition is thermal evaporation deposition, electron beam evaporation, magnetron sputtering deposition, electroless plating, electroplating deposition, etc.; the heat treatment method is the use of rapid annealing furnace (RTA, RTP) ), tube annealing furnace, hot plate or vacuum annealing furnace in the atmosphere of nitrogen or vacuum, heating to 100-600 degrees Celsius for heat treatment for 10-200 minutes.
  • RTA rapid annealing furnace
  • tube annealing furnace hot plate or vacuum annealing furnace in the atmosphere of nitrogen or vacuum, heating to 100-600 degrees Celsius for heat treatment for 10-200 minutes.
  • the thickness of the silicon substrate is 0.1 to 1.5 mm, and the thickness of the deposited metal layer is 10 to 500 nm.
  • the material of the silicon base substrate is polycrystalline silicon or doped monocrystalline silicon, and its resistivity is 0.01-10 ⁇ cm.
  • the thickness of the deposited metal layer is 30 to 150 nanometers.
  • the metal in the metal silicide is selected from transition metals.
  • the metal in the metal silicide is one or more selected from platinum, nickel, titanium, cobalt, palladium, and tungsten.
  • the metal silicide is a combination of one or more selected from platinum silicide, nickel silicide, titanium silicide, cobalt silicide, palladium silicide or tungsten silicide.
  • the silicon substrate can be a silicon wafer with a polishable or non-polable surface, or a silicon substrate with a micro-nano structure can be selected as the substrate.
  • the silicon substrate is prepared by the following method: a photoresist is applied to the surface of the silicon substrate to form a photoresist layer, and an ultraviolet light beam is used to pass and The mask corresponding to the micro-nano structure pattern exposes the photoresist layer, and after development, the photoresist layer obtains the same micro-nano geometric pattern as the mask pattern, and then plasma dry etching By etching, the required micro-structures are manufactured on the silicon substrate, and then a silicon substrate with micro-nano structure can be obtained.
  • the prepared metal silicide electrode also has a micro-nano structure.
  • the electrode materials used for one, two or three of the plurality of electrodes respectively include the metal silicide.
  • one of the plurality of electrodes is a reference electrode without metal silicide.
  • the reference electrode is a silver/silver chloride electrode.
  • the residual chlorine sensor further includes an auxiliary connection mechanism for connecting the electrode material containing the metal silicide to the working circuit.
  • the auxiliary connecting mechanism includes a housing, a circuit board located in the housing, and a wire for connecting the circuit board with the working circuit, and the electrode material includes a metal silicide electrode One end is electrically connected to the circuit board, and the other end is a free end, and the free end is located outside the housing.
  • the auxiliary connection mechanism further includes the auxiliary connection mechanism, which is arranged in the housing, and the two ends are respectively pressed on the circuit board and the electrode material containing metal silicide so that the circuit board and
  • the electrode material includes a metal spring sheet with which the electrode of metal silicide can be electrically conducted.
  • the residual chlorine sensor further includes a potting glue filled in the housing to ensure the waterproof of the internal circuit of the housing.
  • a circuit is provided on the circuit board in the housing, and the circuit not only conducts the electrode and the working circuit, but also has a detection purpose.
  • the above-mentioned residual chlorine sensor based on electrochemical principles is used to detect residual chlorine content, pH value, fluoride ion content, potassium ion content, and calcium ion content in the system.
  • system is an aqueous system or a battery electrolyte system.
  • the water system includes industrial production water, domestic water, sea water, sewage, swimming pool water and natural water.
  • the residual chlorine refers to free chlorine in the system. If the system is water, it means free chlorine in the water.
  • the present invention has the following advantages compared with the prior art:
  • a material composed of a suitable metal silicide is a very ideal residual chlorine detection electrode material.
  • the electrode made from it can not only be used for the detection of residual chlorine, and has high sensitivity, but also the electrode contains residual chlorine. After the electrochemical reaction occurs in a chlorine environment, it can still maintain a very stable electrochemical specificity, the electrical treatment performance is durable, and the electrode is not easy to age. Therefore, the sensor of the present invention can effectively solve the need for frequent electrochemical detection of residual chlorine. The problem of replacing electrodes and inconvenient use. Moreover, the cost of raw materials used in the sensor of the present invention is significantly lower and can be mass-produced.
  • FIG. 1 is a schematic diagram of the structure of the metal silicide electrode of Embodiment 1;
  • FIG. 2 is a schematic front sectional view of the electrode module based on metal silicide of Embodiment 2;
  • FIG. 3 is a schematic side sectional view of a metal silicide-based electrode module of Embodiment 2;
  • 4(a) and (b) are respectively a schematic diagram of a potentiostat circuit and a schematic diagram of an I-V conversion circuit of the residual chlorine sensor of embodiment 3;
  • Fig. 5 is a schematic diagram of the structure of the residual chlorine sensor of embodiment 3.
  • FIG. 6 is a schematic structural diagram of a self-made reference electrode module used in the residual chlorine sensor of Embodiment 3;
  • FIG. 7 is a schematic diagram of the measurement result of the open circuit voltage between the self-made reference electrode module used in the residual chlorine sensor of Example 3 and the commercial reference electrode;
  • Figure 9 shows the relationship between the sensor output signal and the calibration value of free chlorine when the residual chlorine sensor of embodiment 3 is tested in a water body with a pH of 6.86 in an environment of 23°C and a free chlorine content;
  • Figure 10 shows the results of the residual chlorine sensor of Example 3 tested once a day for five consecutive days in a water body with a pH of 6.86 and a free chlorine content of 2mg/L in an environment of 23°C;
  • Figure 11 is a test of free chlorine content in a water body with a pH of 6.86 using five residual chlorine sensors of Example 3 in an environment of 23°C, and the relationship between the sensor measurement value and the free chlorine calibration value;
  • Figure 12 shows the relationship between the sensor measurement value and the free chlorine calibration value of the residual chlorine sensor of embodiment 3 in different pH water bodies
  • FIG. 13 is the relationship between the residual chlorine measurement value of a specific water sample and the temperature measured by the residual chlorine sensor of embodiment 3;
  • Figure 14 is a drawing of (RC T -RC 23 )/RC 23 versus T-23 in Embodiment 3;
  • 15(a) and (b) are circuit diagrams of two voltage followers, U4A and U4B, of the residual chlorine sensor of embodiment 4;
  • 16 is a schematic diagram of the structure of the residual chlorine sensor of embodiment 4.
  • 17 is a schematic diagram of the relationship between the sensor output signal and the pH calibration value when the residual chlorine sensor of embodiment 4 is tested in a test solution of different pH values in an environment of 23°C;
  • 18 is a schematic diagram of the relationship between the measured value of the sensor and the calibration value of pH using three residual chlorine sensors of Example 4 in a 23°C environment to perform a pH test;
  • 19 is a schematic diagram of the relationship between the obtained sensor output signal and the ORP calibration value when the residual chlorine sensor of Example 4 is tested in a water body with different oxidation-reduction potentials in an environment of 23°C;
  • Figure 20 (a) and (b) are circuit diagrams of the I-V conversion circuit and the voltage follower of the residual chlorine sensor of embodiment 5;
  • 21 is a schematic diagram of the structure of the residual chlorine sensor of Embodiment 5.
  • Figure 22 shows the relationship between the obtained sensor output signal and the TDS calibration value when the residual chlorine sensor of Example 5 is tested in a water body with different TDS in an environment of 23°C.
  • metal silicide electrode 101, silicon substrate; 102, metal silicide layer; 2. housing; 3. circuit board; 4. metal spring sheet; 5. potting glue; 6. wire; 7 8. Shell; 8. Silver/silver chloride electrode; 9. Silver wire; 10. Agar gel containing saturated potassium chloride; 11. Porous material; 12. Waterproof glue; 13. Electrode module based on metal silicide; 14. Reference electrode module; 15. External circuit board; 16. Liquid to be tested.
  • the material of the electrode is usually metal or metal alloy, and the electrode is made of metal or metal alloy.
  • the cost is often relatively high.
  • the electrode is used in a residual chlorine sensor, the sensor is greatly improved.
  • the cost is not suitable for mass production.
  • the residual chlorine sensor prepared by the traditional electrochemical electrode electrode material is metal or metal alloy
  • the traditional electrochemical electrode will react with the residual chlorine chemically and affect
  • the durability of electrical treatment performance is weak, and stable detection is impossible. This is a technical problem that cannot be solved in the field for 20 to 30 years.
  • the inventor of the present application prepared a new type of silicide conductive ceramic from a semiconductor process through a cross-border process, and unexpectedly found that metal silicide has good electrode characteristics.
  • the metal silicide is used to prepare an electrode, and the electrode undergoes electrochemistry in a residual chlorine environment. After the reaction, it can still maintain a very stable electrochemical specificity, with strong electrical treatment performance and durability, and the electrode is not easy to age.
  • the metal silicide electrode is used for the residual chlorine sensor, which can stably detect residual chlorine, breaking through the traditional electrode that cannot stably detect residual Technical difficulties of chlorine.
  • the metal silicide electrode 1 has a two-layer structure, in which one layer is a silicon substrate 101, and the other layer is formed on the silicon substrate 101.
  • the metal silicide layer 102 is formed on the silicon substrate 101.
  • the thickness of the metal silicide layer is 10 to 500 nanometers, and the thickness of the silicon substrate is 0.1 to 1.5 mm.
  • the metal silicide is a combination of one or more selected from platinum silicide, nickel silicide, titanium silicide, cobalt silicide, palladium silicide or tungsten silicide.
  • the metal silicide electrode 1 is prepared by the following method:
  • step (2) The workpiece prepared in step (1) is placed in an oxygen-free environment for heat treatment so that silicon and metal react to form metal silicide;
  • step (3) Cutting the workpiece prepared in step (2) to form a metal silicide electrode.
  • step (1)
  • the material of the silicon base substrate is polycrystalline silicon or doped monocrystalline silicon, and its resistivity is 0.01-10 ⁇ cm.
  • the thickness of the silicon substrate is 0.2 mm to 1.5 mm, for example, 0.5 mm can be selected.
  • step (2)
  • the metal is selected from transition metals.
  • the metal is one or more selected from platinum, nickel, titanium, cobalt, palladium, and tungsten. Specifically, platinum and tungsten can be selected.
  • the thickness of the metal layer is 10-500 nanometers.
  • the thickness of the metal layer is 30 to 150 nm. Specifically, 50 nanometers and 100 nanometers.
  • the deposition method is thermal evaporation deposition method, electron beam evaporation deposition method, magnetron sputtering deposition method, electroless plating deposition method, electroplating deposition method, etc.
  • the heat treatment method is to use a rapid annealing furnace (RTA, RTP), a tubular annealing furnace, a hot plate or a vacuum annealing furnace in a nitrogen or vacuum atmosphere, and heat to 100-600 degrees Celsius for 10-200 minutes.
  • RTA rapid annealing furnace
  • tubular annealing furnace a hot plate or a vacuum annealing furnace in a nitrogen or vacuum atmosphere
  • heat 100-600 degrees Celsius for 10-200 minutes.
  • the metal silicide-based electrode module provided by this embodiment, see Figures 2 to 3, includes a metal silicide electrode 1, a casing 2, a circuit board 3 fixedly arranged in the casing 2 and a circuit board 3 for connecting the circuit board 3 to the outside world.
  • a metal silicide electrode 1 For the conductive wire 6 of the electrical circuit, one end of the metal silicide electrode 1 is in contact with the circuit board 3 and electrically conductive, and the other end is a free end, and the free end is located outside the housing 2.
  • the metal silicide-based electrode module also includes a metal spring sheet which is arranged in the housing 2 and whose two ends are respectively pressed on the circuit board 3 and the metal silicide electrode 1 so that the circuit board 3 and the metal silicide electrode 1 can be electrically connected. 4.
  • the potting glue 5 filled in the shell 2 to ensure the waterproof of the internal circuit of the shell 2.
  • the circuit board 3 in the housing 2 is provided with a circuit, which not only can connect the metal silicide electrode 1 with an external circuit, but also has a detection purpose. Or, the circuit provided on the circuit board 3 in the housing 2 is only used to connect the metal silicide electrode 1 with an external circuit.
  • the shell 2 is made of hard plastic, and the material includes but not limited to ABS engineering plastic, PE, PS, etc.;
  • the material of the metal spring 4 can be copper, glass copper, stainless steel, etc.;
  • the potting glue 5 can be AB epoxy resin or the like.
  • the structure of the metal silicide electrode 1 is the same as that of the first embodiment, and the metal spring sheet 4 is pressed on the metal silicide layer 102 of the metal silicide electrode 1.
  • the preparation of the metal silicide-based electrode module is as follows:
  • the upper end of the casing 2 is provided with a wire hole and a glue hole, and the lower end is provided with a metal silicide electrode 1 socket.
  • the other end of the wire 6 passes through the casing 2 from the wire hole and extends to the outside of the casing 2. According to further It needs to be connected to an external circuit, and its function is as an output signal and/or power supply wiring.
  • One end of the metal silicide electrode 1 enters the housing 2 through the insertion hole at the lower end of the housing 2.
  • This embodiment provides a residual chlorine sensor, which is designed according to the principle of amperometric measurement and adopts a three-electrode working mode to detect the content of certain substances to be detected in the water body that are prone to oxidation-reduction reactions.
  • the three electrodes are working electrode (WE), reference electrode (RE) and counter electrode (CE).
  • WE working electrode
  • RE reference electrode
  • CE counter electrode
  • the residual chlorine sensor is working, a constant voltage is applied across the working electrode and the reference electrode to keep the working electrode at a stable potential.
  • an electrocatalytic reaction of the object to be detected occurs on the working electrode, and the current passing through the working electrode is related to the concentration of the object to be detected. Therefore, the content of the object to be detected can be obtained by measuring the current on the working electrode.
  • the circuit design of the residual chlorine sensor is shown in Figure 4.
  • Working principle of the circuit The circuit is composed of a potentiostat circuit and an I-V conversion circuit.
  • U4D and the auxiliary circuit form a potentiostat circuit.
  • the potential of the reference electrode RE is applied through RC_REF_N to provide a stable working voltage to the working electrode WE.
  • U4C and the auxiliary circuit form an I-V conversion circuit, which performs ad sampling through the p2.2 port.
  • the role of RE is to provide a stable electrode potential during the measurement process to ensure that the potential of the working electrode remains stable during the measurement process.
  • the residual chlorine sensor includes a working circuit, two electrode modules 13 based on metal silicide, a reference electrode module 14 and an external circuit board 15.
  • the working circuit is integrated on the external circuit board 15, and two are based on The metal silicide electrode module 13 and a reference electrode module 14 are electrically connected to the external circuit board 15 respectively.
  • the circuit design shown in FIG. 4 is integrated on the external circuit board 15, and the circuit on the circuit board 3 of the metal silicide-based electrode module 13 is only used to connect the metal silicide electrode 1 and the working circuit.
  • the circuit on the circuit board 3 of the metal silicide-based electrode module 13 not only conducts the metal silicide electrode 1 and the working circuit, but also has a detection purpose.
  • the structure design of the electrode module 13 based on metal silicide is the same as that of the second embodiment.
  • one of the metal silicide electrodes of the two metal silicide-based electrode modules 13 is used as the working electrode (WE), the other is used as the counter electrode (CE), and the reference electrode module 14 is used as the reference electrode (RE). )use.
  • the reference electrode module can use a commercial reference electrode, such as a commercially available silver/silver chloride reference electrode. You can also use a self-made reference electrode module.
  • the self-made reference electrode module includes a housing 7 with a containing cavity, a silver/silver chloride electrode 8 arranged in the housing 7, a silver wire 9 extending from the silver/silver chloride electrode 8, and Inside the shell 7 and one end passes through one end of the shell 7 and extends out of the porous material piece 11 of the shell 7 and the agar gel 10 containing saturated potassium chloride filled in the shell 7, one end of the silver wire 9 passes through the other end of the shell 7 And extend to the outer shell 7.
  • the shell 7 is made of hard plastic, and the material includes but is not limited to ABS engineering plastics, PE, PS, etc.; the shape of the shell is not limited, and the volume is 1-50 cubic centimeters; the porous material piece 11 is fiber or porous ceramic.
  • the shell 7 can be composed of a shell and a matching upper cover.
  • the upper cover is provided with a wire hole and a liquid injection hole.
  • a silver/silver chloride electrode 8 made of silver wire is installed inside the shell.
  • the extended silver wire extends out of the shell through the wire hole on the upper cover.
  • the lower end of the shell is provided with a liquid connection communication hole, a section of porous material piece 11 of appropriate size is inserted into the communication hole, and one end of the porous material piece 11 extends into the inside of the shell, its function is to make the gel in the shell and the outside to be measured Ionic communication is formed between the solutions, and at the same time, the diffusion rate of chloride ions in the shell to the outside solution to be tested is restricted; in the shell, the silver/silver chloride electrode 8, the porous material 11 and the inner wall of the shell are filled with saturated chloride Potassium agar (1-5%) gel; the upper cover is also provided with a liquid injection hole through which hot liquid sol can be injected into the shell to fill the internal space. Between the shell and the upper cover, the wire hole and the liquid injection hole are sealed by the waterproof glue 12.
  • the production method of the silver/silver chloride electrode 8 use a winding machine to wind a silver wire with a diameter of 0.1-1.0 mm into a spiral shape with an inner diameter of 2.0-10 mm to increase the surface area per unit volume; at a concentration of 5% Soaked in sodium hypochlorite solution for 12 hours to obtain a silver/silver chloride electrode; this electrode was repeatedly pulled five times in 12 ml of tetrahydrofuran solution containing 0.01g sodium chloride and 0.4g polyvinyl chloride, and then dried at room temperature for 48 hours , And then repeated pulling five times in 5% Nafion solution, and then treated at 80 °C for 1 hour, and finally taken out and cooled to room temperature to obtain silver/silver chloride electrode.
  • ABS engineering plastic is used as the shell, the inner size of the shell is 50 ⁇ 20 ⁇ 10 mm, and the thickness of the shell is 2 mm; the diameter of the silver wire used is 0.2 mm, and the inner diameter of the spiral shape formed by winding is 2.5 mm; the porous material piece 11 is the fiber strip; the mass fraction of agar in the agar gel is 3%.
  • the two metal silicide-based electrode modules 13 used as the working electrode and the counter electrode are installed
  • the exposed metal silicide electrode and the fiber strips of the reference electrode module 14 are immersed in the test solution 16, and the test solution 16 is used as an electrolyte solution to conduct conduction to form a circuit loop.
  • the current passing through the working electrode can be converted into an output signal, and the acquisition frequency can be set. Since the circuit design has the function of potential correction, the working electrode can maintain a stable potential, so the signal of this module can maintain a good linear relationship with the content of the analyte in the water, and a linear fitting equation can be obtained accordingly.
  • the senor runs in the water to obtain the output signal, and calculates through the linear fitting equation to obtain the content of the analyte in the water.
  • the influence of temperature and pH needs to be considered, and correction should be made according to actual conditions.
  • the residual chlorine sensor provided in this embodiment can be used to detect the content of certain substances to be detected that are prone to oxidation-reduction reactions in water bodies, such as the residual chlorine content in water bodies such as tap water, sewage, swimming pool water, and natural water.
  • water bodies such as tap water, sewage, swimming pool water, and natural water.
  • Different test objects correspond to different concentration ranges of residual chlorine (Ministry of Health of the People’s Republic of China. Sanitary Standards for Drinking Water [S].
  • the content of free residual chlorine in the water should not be less than 0.3mg/L; the standard value of free residual chlorine in artificial swimming pool water is 0.3mg/L ⁇ 0.5mg/L; decontaminate with chlorine
  • the content of free residual chlorine on the surface of the tableware after disinfection by the agent should be less than 0.3mg/L; the measurement range of residual chlorine in industrial circulating cooling water is 0.03mg/L ⁇ 2.5mg/L.
  • the measuring range of residual chlorine is set to 0-8mg/L, which is only used as an example to illustrate the function of the sensor. In actual use, it is necessary to consider setting the detection range of the sensor according to the requirements of the specific detection object.
  • hypochlorous acid is a weak acid, which is partially decomposed into hydrogen ions and hypochlorite ions, and hypochlorous acid is oxidized on the electrode surface- Reduction reaction (formula (1) and formula (2)).
  • a constant voltage needs to be applied across the working electrode and the reference electrode to keep the potential of the working electrode constant.
  • HOCl and OCl - electrocatalytic reaction occurs on the PtSi working electrode.
  • the electrode signal has a linear relationship with the content of the test substance in the water.
  • the platinum silicide electrode is used as the working electrode and the counter electrode.
  • the preparation of the platinum silicide electrode is as follows: a single-side polished P-type silicon wafer with a thickness of 0.5 mm is used as the substrate, and the polished surface is plated with 50 nm platinum by electron beam evaporation deposition. , Then heat treatment in a tube annealing furnace in a nitrogen atmosphere to react silicon and platinum to generate platinum silicide, and then use a blade cutting to cut the silicon substrate with platinum silicide formed on the surface into 3 ⁇ 9.5 ⁇ 0.5 mm to obtain platinum silicide electrodes. , The heat treatment temperature is 400°C, and the heat treatment time is 60 minutes.
  • the area of platinum silicide electrode exposed to the outside of the module is 3 ⁇ 5 mm; the shell is ABS engineering plastic; the metal spring is copper; the potting glue is AB epoxy resin; The size of the electrode socket is 3.2 ⁇ 0.7 mm.
  • the exposed platinum silicide electrode and the fiber strips of the reference electrode module on the two metal silicide-based electrode modules serving as the working electrode and the counter electrode are immersed in the water to be measured.
  • apply a constant voltage across the working electrode and the reference electrode to keep the working electrode at +350mV potential (vs reference electrode, ie RC_REF_P-RC_REF_N 350mV), and then read the sensor output signal , Collection frequency can be set.
  • Residual chlorine calibration value (mg/L) Residual chlorine measurement value (mg/L) Absolute measurement deviation (mg/L) 0.05412 0 0.05412 1.66644 2 0.33356 0.04379 0 0.04379 5.75828 6 0.24172 0.04366 0 0.04366 2.21797 2 0.21797 0.03462 0 0.03462 1.95444 2 0.04556
  • the residual chlorine sensor responds to various interfering substances that may exist in the water body (the response value unit is mg/L, and the response current value is measured by The linear fitting equation of residual chlorine is converted into the corresponding residual chlorine content) as shown in Table 2.
  • Interfering substances concentration Response value (mg/L) MgCl 2 100mM 0.03914 CuSO 4 100 ⁇ M -0.02789 NH 4 Cl 100mM -0.02889 KCl 300mM 0.01 CaCl 2 100mM 0.07455 ZnCl 2 100mM 0.05481
  • the sensor output signal is related to the pH value of the water body to be measured.
  • the pH of the water to be measured is between 5 and 8, the measurement result is not affected by the pH.
  • the pH is in the range of 5-8, without compensation.
  • Chlorine measured value obtained when the current temperature T (°C), RC T is chlorine in the temperature measurements T, RC 23 is detected at the same density using the same 23 °C of sensors: temperature compensation can be performed according to the following method . Plotting (RC T -RC 23 )/RC 23 against T-23 and performing linear fitting, the fitting formula y kx can be obtained. Where k is the temperature correction coefficient. Then the temperature correction of the residual chlorine sensor can be performed with the following formula:
  • Perform linear fitting to obtain the fitting formula y kx.
  • Temperature correction coefficient k 0.03745°C -1 .
  • the respective temperature sensor measurement before correction values into the formula RC M RC C RC M / [1 + k (T-23)], to obtain a residual chlorine concentration after temperature correction.
  • This embodiment provides a residual chlorine sensor, which is designed according to the measurement principle of the potentiometric method, and uses the relationship between the electrode potential and the activity (or concentration, etc.) of a certain ion in the solution to determine the activity of the measured substance. Degree (or concentration). It is based on measuring the electromotive force of the battery.
  • Its chemical battery is composed of the liquid to be tested as the electrolyte solution, and two electrodes are inserted in it. One is an indicator electrode with a quantitative relationship between the electrode potential and the activity (or concentration, etc.) of the measured liquid.
  • the other is a reference electrode with a stable potential, and the content of the substance to be measured is determined by measuring the electromotive force of the battery.
  • the circuit design of the residual chlorine sensor is shown in Figure 15.
  • the working principle of the circuit is composed of two voltage followers, U4A and U4B.
  • U4B is used as the power supply module of the reference electrode, and the reference electrode is provided with voltage through OUT2.
  • OUT2 is 0V in ORP application. In pH applications, OUT2 is 1V).
  • U4A acts as a buffer to provide readings for the AD module.
  • OUT is connected with the indicator electrode and output to the AD module through p2.3.
  • the residual chlorine sensor includes a working circuit, an electrode module 13 based on metal silicide, a reference electrode module 14 and an external circuit board 15.
  • the working circuit is integrated on the external circuit board 15, and one based on metal silicide
  • the electrode module 13 and a reference electrode module 14 are electrically connected to the external circuit board 15 respectively.
  • the circuit design shown in FIG. 15 is integrated on the external circuit board 15, and the circuit on the circuit board 3 of the metal silicide-based electrode module 13 is only used to connect the metal silicide electrode 1 and the working circuit.
  • the circuit on the circuit board 3 of the metal silicide-based electrode module 13 not only conducts the metal silicide electrode 1 and the working circuit, but also has a detection purpose.
  • the structure design of the electrode module 13 based on metal silicide is the same as that of the second embodiment.
  • the metal silicide electrode of a metal silicide-based electrode module 13 is used as an indicator electrode
  • the reference electrode module 14 is used as a reference electrode.
  • the reference electrode module 14 used in the sensor is the same as that in the third embodiment.
  • the residual chlorine sensor of this embodiment When the residual chlorine sensor of this embodiment is used to detect the liquid to be tested, as shown in FIG. 16, the exposed metal silicide electrode and the fiber of the reference electrode module 14 on the metal silicide-based electrode module 13 used as the indicator electrode
  • the strip is immersed in the test liquid 16 (water to be tested), and the test liquid is used as the electrolyte solution.
  • the reference electrode module 14 can provide a stable and constant potential, and the electromotive force of the metal silicide-based electrode module as the indicator electrode is the same as There is a quantitative relationship between the content of the measured substance, and the potential difference between the metal silicide-based electrode module and the reference electrode module can be converted into an output signal by the sensor circuit. Therefore, the output signal of the residual chlorine sensor in the test solution 16 can be calculated by the fitting equation to obtain the content of the test substance. In actual application, the impact of the test environment needs to be considered, and corrections should be made according to the actual situation.
  • the residual chlorine sensor of this embodiment can be used to detect the content of a variety of ions, including but not limited to hydrogen ions (that is, pH), chloride ions, fluoride ions, potassium ions, calcium ions, and can also be used to detect the oxidation of the test liquid Reduction potential (ORP).
  • hydrogen ions that is, pH
  • chloride ions that is, fluoride ions
  • potassium ions calcium ions
  • ORP test liquid Reduction potential
  • the detection principle is as follows:
  • tungsten atoms on the surface of tungsten silicide are oxidized to form a tungsten oxide layer, and the solubility of tungsten oxide in water is very small.
  • a tungsten silicide electrode When a tungsten silicide electrode is immersed in water, the tungsten oxide on the electrode surface will be saturated with water and undergo the following hydrolysis reaction to generate tungsten ions:
  • the tungsten ions on the electrode surface have a tendency to obtain electrons and be reduced to tungsten atoms:
  • E 0 is the standard potential of the electrode
  • R is the gas constant
  • T is the temperature
  • F is the Faraday constant
  • T is the absolute temperature value
  • n is the number of electrons transferred
  • [M n+ ] is the concentration of ions.
  • the unit of potential in the formula is V.
  • the potential difference E can be obtained by measuring the open circuit voltage between the tungsten silicide electrode and the reference electrode, thereby obtaining the pH value of the solution.
  • a tungsten silicide electrode is used as an indicator electrode.
  • the preparation of the tungsten silicide electrode is as follows: a single-sided polished P-type silicon wafer with a thickness of 0.5 mm is used as a substrate, and 100 nm tungsten is plated on the polished surface by electron beam evaporation deposition. Then in a nitrogen atmosphere, a rapid annealing furnace (RTA) is used to heat the silicon and tungsten to react to generate tungsten silicide, and then use a blade cutting to cut the silicon substrate with tungsten silicide formed on the surface into 3 ⁇ 9.5 ⁇ 0.5 mm to obtain a tungsten silicide electrode.
  • the heat treatment temperature is 400°C
  • the heat treatment time is 10 minutes.
  • the area of the tungsten silicide electrode exposed outside the electrode module is 3 ⁇ 5 mm; the shell is ABS engineering plastic; the metal spring is copper; the potting glue is AB epoxy resin; on the shell The size of the electrode socket is 3.2 ⁇ 0.7 mm.
  • the metal silicide-based electrode module 13 equipped with tungsten silicide electrodes is used as the indicator electrode in the circuit, and the reference electrode module 14 is used as the reference electrode in the circuit, and is connected to the circuit designed as described in FIG. 15.
  • the tungsten silicide electrode and the fiber strips of the reference electrode module exposed on the metal silicide-based electrode module as the indicator electrode are immersed in the water to be measured.
  • the sensor output signal is collected through the circuit, and the collection frequency can be set.
  • the process of each sensor test is as follows: the sensor is powered on and works continuously for 10 seconds, collecting 10 data per second, and calculating the average value of the data as the final collected output signal of this test.
  • the residual chlorine sensor is used to test in the test solution with different pH values (all are calibrated with Mettler pH meter), and the relationship between the sensor output signal and the pH calibration value is obtained, as shown in Figure 17. Show.
  • pH calibration value pH measurement Absolute measurement deviation 5.07 5.06859 0.00141 5.07 4.96306 0.10694
  • Test the consistency of the residual chlorine sensor In an environment of 23°C, use three residual chlorine sensors for pH test. The relationship between the sensor measurement value and the pH calibration value is shown in Figure 18. The results show that the residual chlorine sensor has good consistency.
  • the ORP indicator electrode is an electrode that can absorb or release electrons on the surface for potential measurement. At the same time, it requires its chemical properties to be stable and resistant to chemical shocks.
  • Solution ORP can be obtained by measuring the potential difference between the ORP indicator electrode and the reference electrode.
  • the sensor output signal is an output signal, reflecting the open circuit voltage between the platinum silicide electrode and the reference electrode. Therefore, the output signal can have a good linear relationship with the ORP of the test liquid, and a linear fitting equation can be obtained based on this, and then the linear fitting equation can be calculated to obtain the ORP of the test liquid.
  • a platinum silicide electrode is used as an indicator electrode.
  • the preparation of the platinum silicide electrode is as follows: a single-side polished P-type silicon wafer with a thickness of 0.5 mm is used as a substrate, and the polished surface is plated with 50 nm platinum by the electron beam evaporation method. Heat treatment in a tube annealing furnace in a nitrogen atmosphere to react silicon and platinum to generate platinum silicide, and then use blade cutting to cut the platinum silicide into 3 ⁇ 9.5 ⁇ 0.5 mm to obtain a platinum silicide electrode. The heat treatment temperature is 400°C and the heat treatment time For 60 minutes.
  • the area of platinum silicide electrode exposed to the outside of the module is 3 ⁇ 5 mm; the shell is ABS engineering plastic; the metal spring is copper; the potting glue is AB epoxy resin; on the shell The size of the electrode socket is 3.2 ⁇ 0.7 mm.
  • the metal silicide-based electrode module equipped with platinum silicide electrodes is used as the ORP indicator electrode in the circuit, and the reference electrode module is used as the reference electrode in the circuit, connected to the circuit designed as shown in Figure 15.
  • the exposed platinum silicide electrode on the metal silicide-based electrode module as the ORP indicator electrode and the fiber strips of the reference electrode module are immersed in the water to be measured.
  • the sensor output signal is collected through the circuit, and the collection frequency can be set.
  • the process of each test of the residual chlorine sensor is: the sensor is powered on and runs for 10 seconds, collecting 10 data per second, and calculating the average value of the data as the final collected output signal of this test.
  • This embodiment provides a residual chlorine sensor.
  • the residual chlorine sensor is designed according to the resistance measurement method and adopts two conductivity electrodes. It can be used to measure the conductivity and dissolution of industrial production water, domestic water, sea water, battery electrolyte, etc. Total Sexual Solids (TDS).
  • TDS Total Sexual Solids
  • the metal silicide electrodes of two metal silicide-based electrode modules are used as conductivity electrodes to be immersed in the solution to be measured, and the conductivity of the intermediate solution is measured by the AC bridge method.
  • the relative position of the two metal silicide-based electrode modules as conductivity electrodes is fixed.
  • the two electrodes can be placed in parallel with the metal layers facing each other; the two electrodes can also be placed on the same plane.
  • the exposed metal silicide electrode on the metal silicide-based electrode module When in use, immerse the exposed metal silicide electrode on the metal silicide-based electrode module as a conductivity electrode in water, apply alternating current at both ends of the two electrode modules, and convert the current value flowing through the electrode into the output of the sensor circuit
  • the signal has a correlation with the conductivity of the water body, and a linear fitting equation can be obtained based on this.
  • the sensor runs in the test liquid to obtain the output signal, and calculates through the linear fitting equation to obtain the conductivity of the test liquid.
  • the influence of temperature and pH needs to be considered, and correction should be made according to actual conditions.
  • U1A is an I-V conversion circuit connected to the ADC module through P1.6, and U1B forms a voltage follower.
  • p2.7 is connected to the IDAC module, and a voltage signal of 0.5v—1v—0V—0.5V is applied to one side electrode through the IDAC module.
  • Two of the conductivity electrodes are connected to pins 2 and 7 respectively.
  • the residual chlorine sensor includes a working circuit, two electrode modules 13 based on metal silicide, and an external circuit board 15.
  • the working circuit is integrated on the external circuit board 15, and the two electrode modules 13 based on metal silicide are respectively It is electrically connected to the external circuit board 15.
  • the circuit shown in FIG. 20 is integrated on the external circuit board 15, and the circuit on the circuit board 3 of the metal silicide-based electrode module 13 is only used to connect the metal silicide electrode 1 and the working circuit.
  • the circuit on the circuit board 3 of the metal silicide-based electrode module 13 not only conducts the metal silicide electrode 1 and the working circuit, but also has a detection purpose.
  • the residual chlorine sensor of this embodiment is used to detect the total dissolved solids (TDS) of the aqueous solution
  • TDS total dissolved solids
  • the TDS of the solution can be calculated by the above formula ( ⁇ is an empirical value).
  • the platinum silicide electrode is used as the conductivity electrode.
  • the preparation of the platinum silicide electrode is as follows: a single-sided polished P-type silicon wafer with a thickness of 0.5 mm is used as a substrate, and the polished surface is plated with 50 nm platinum by electron beam evaporation deposition. , Then heat treatment in a tube annealing furnace in a nitrogen atmosphere to react silicon and platinum to generate platinum silicide, and then use a blade cutting to cut the silicon substrate with platinum silicide formed on the surface into 3 ⁇ 9.5 ⁇ 0.5 mm to obtain platinum silicide electrodes. , The heat treatment temperature is 400°C, and the heat treatment time is 60 minutes.
  • the area of the platinum silicide electrode exposed to the electrode module is 3 ⁇ 5 mm; the positions of the two electrodes are on the same plane, and the distance between the two electrodes is 3 mm; the shell is ABS engineering plastic; metal The spring piece is copper; the potting glue is AB epoxy resin; the size of the electrode socket on the shell is 3.2 ⁇ 0.7 mm.
  • a metal silicide-based electrode module equipped with platinum silicide electrodes was used as a conductivity electrode in the circuit and connected to the circuit designed as shown in FIG. 20.
  • the exposed platinum silicide electrode on the metal silicide-based electrode module as the conductivity electrode is immersed in the test liquid 16 (water to be tested), as shown in FIG. 21.
  • the sensor output signal is collected through the circuit, and the collection frequency can be set.
  • the process of each sensor test is as follows: the sensor is powered on and works continuously for 10 seconds, collecting 10 data per second, and calculating the average value of the data as the final collected output signal of this test.
  • the residual chlorine sensor is used to test in water bodies with different TDS, and the relationship between the sensor output signal and the TDS calibration value is shown in Figure 22.
  • TDS calibration value (ppm) TDS measurement value (ppm) Absolute measurement deviation (ppm) Relative error(%) 65 64.21697 0.78303 1.20466
  • two electrode modules based on metal silicide and one reference electrode module can be assembled into a residual chlorine sensor, and then the circuit can be designed to switch between different times at different times.
  • the working mode such as two electrode modules based on metal silicide and one reference electrode module working at the same time (such as the three-electrode working mode of Example 3), one electrode module based on metal silicide and one
  • the working mode of the reference electrode module working at the same time (the working mode of embodiment 4), the working mode of two metal silicide-based electrode modules working at the same time (the working mode of embodiment 5)
  • the sensor can monitor multiple indicators of the water body.
  • the above combination is only one combination of the present invention, and other combinations can also be used as needed.

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Abstract

一种基于电化学原理的余氯传感器及其用途，余氯传感器包括工作电路以及多个电极，多个电极中至少有一个所采用的电极材料包括金属硅化物。由金属硅化物材料制成的电极，不仅可以用于余氯的检测，灵敏度高，而且该电极在含有余氯的环境下发生电化学反应后仍然能够保持非常稳定的电化学特性，电处理性能耐久性强，电极不易老化，因而，本发明的传感器可以有效解决传统电化学检测余氯所存在的需要频繁更换电极、使用不便的难题。本发明的传感器采用的原料成本显著更低，且可以大规模生产。

Description

一种基于电化学原理的余氯传感器及其用途 技术领域
本发明属于传感器技术领域，具体涉及一种基于电化学原理的余氯传感器及其用途。
背景技术
现有技术中，在余氯传感器领域，余氯的测定方法常用的有N.N-二乙基对苯二胺(DPD)分光光度法和电化学法。
DPD分光光度法的测定原理是DPD与水中游离余氯迅速反应而生成红色化合物，在515nm波长下，采用分光光度法测定其吸光度，测定余氯。分光光度法操作复杂，实时检测性差，而且水中存在多种物质(如锰的氧化物、溴、碘化钾、铜等物质)时将干扰余氯检测结果，此外，还存在因试剂本身容易变色等导致余氯测量结果不稳定、准确率偏低的问题。
电化学法是利用基于电化学原理的传感器来进行余氯检测。现有技术中用于余氯检测的传感器的电极一般为金属(如铂)或金属合金电极。长期以来，人们在实践中发现采取该电极，电处理性能耐久性弱，电极易老化，无法实现长期稳定地检测余氯，必须经常性地进行更换电极，导致使用成本非常高，且给使用造成了诸多不便。自问题发现至今已有三十年，然而相关问题仍未得到有效解决。此外，现有的电极难以实现大规模生产，且原料成本亦很高。
发明内容
本发明目的是为了克服现有技术中基于电化学原理的余氯传感器的不足而提供一种改进的余氯传感器及其用途。
为达到上述目的，本发明所采用的技术方案为：
一种基于电化学原理的余氯传感器，包括工作电路以及多个电极，所述多个电极中至少有一个所采用的电极材料包括金属硅化物。
进一步地，所述多个电极中至少有工作电极和对电极，所述工作电极和/或对电极采用的电极材料包括金属硅化物。
进一步地，所述多个电极中至少有一个所采用的电极材料为二层结构或三层结构，当所述电极材料为二层结构时，其中一层由所述金属硅化物构成，另一层由硅构成；当所述电极材料为三层结构时，中间层由硅构成，位于中间层两侧的外层由所述金属硅化物构成。
更进一步地，所述的二层结构或三层结构中，由金属硅化物构成的层的厚度为10～500纳米，由硅构成的层的厚度为0.1～1.5毫米。
更进一步地，所述的二层结构或三层结构通过以硅基材为衬底，沉积金属层后，经热处理形成。
所述沉积采用的沉积方法为热蒸发沉积法、电子束蒸发沉积法、磁控溅射沉积法、化学镀沉积法、电镀沉积法等；所述热处理的方法为采用快速退火炉(RTA，RTP)、管式退火炉、热板或真空退火炉在气氛为氮气或真空条件下，加热至100-600摄氏度热处理10-200分钟。
优选地，所述的硅基材的厚度为0.1～1.5毫米，沉积的金属层的厚度为10～500纳米。
所述硅基材衬底的材质为多晶硅或掺杂单晶硅，其电阻率为0.01-10Ωcm。
更优选地，沉积的金属层的厚度为30～150纳米。
进一步地，所述的金属硅化物中的金属选自过渡金属。
优选地，所述的金属硅化物中的金属为选自铂、镍、钛、钴、钯、钨中的一种或多种。
进一步地，所述的金属硅化物为选自硅化铂、硅化镍、硅化钛、硅化钴、硅化钯或硅化钨中的一种或多种的组合。
在某些具体实施方面，所述硅基材衬底可选表面可抛光或不可抛光的硅片，也可选具有微纳结构的硅基材作为衬底。
当选择具有微纳结构的硅基材作为衬底时，硅衬底通过以下方法制备得到：将光致抗蚀剂涂于硅基材的表面形成光致抗蚀剂层，利用紫外光束通过与微纳结构图形对应的掩膜对所述光致抗蚀剂层进行曝光，经显影后在所述光致抗蚀剂层获得与掩膜图形相同的微纳几何图形，再经等离子干法刻蚀，在硅基材上制造出所需的微型结构，即可得到具有微纳结构的硅衬底。
若选择具有微纳结构的硅基材作为硅衬底，则制备出的金属硅化物电极也具有微纳结构。
进一步地，所述多个电极中有一个、二个或三个所采用的电极材料分别包括所述金属硅化物。
进一步地，所述多个电极中有一个为不含金属硅化物的参比电极。
优选地，所述参比电极为银/氯化银电极。
进一步地，所述余氯传感器还包括辅助连接机构，用于将所述电极材料包含金属硅化物的电极与所述工作电路导通。
更进一步地，所述的辅助连接机构包括壳体、位于所述壳体内的电路板、用于将所述电路板与所述工作电路导通的导线，所述电极材料包含金属硅化物的电极的一端与所述电路板接触电导通，另一端为自由端，且该自由端位于所述壳体之外。
在某些具体实施方面，所述的辅助连接机构还包括设置在所述壳体内且两端分别压设在所述电路板和所述电极材料包含金属硅化物的电极上使得所述电路板和所述电极材料包含金属硅化物的电极能够电导通的金属弹簧片。
在某些具体实施方面，所述余氯传感器还包括填充在所述壳体内的灌封胶，以保证所述 壳体内部电路的防水。
在某些具体实施方面，所述壳体内的电路板上设置有电路，所述电路除导通所述电极与所述工作电路外，还具有检测用途。
本发明采取的另一技术方案是：一种上述所述的基于电化学原理的余氯传感器用于检测体系中的余氯含量、pH值、氟离子含量、钾离子含量、钙离子含量，体系的氧化还原电位、体系的电导率或体系中溶解性固体总量的用途。
进一步地，所述体系为水系体系或电池电解液体系。
更进一步地，所述水系体系包括工业生产用水、生活用水、海水、污水、泳池水和天然水。
本发明中，所述余氯指的是体系中的游离氯。若体系为水，则指水中的游离氯。
由于上述技术方案运用，本发明与现有技术相比具有下列优点：
本发明人意外发现，由合适的金属硅化物构成的材料是非常理想的余氯检测电极材料，由其制成的电极，不仅可以用于余氯的检测，灵敏度高，而且该电极在含有余氯的环境下发生电化学反应后仍然能够保持非常稳定的电化学特定，电处理性能耐久性强，电极不易老化，因而，本发明的传感器可以有效解决传统电化学检测余氯所存在的需要频繁更换电极、使用不便的难题。而且，本发明的传感器采用的原料成本显著更低，且可以大规模生产。
附图说明
图1为实施例1的金属硅化物电极的结构示意图；
图2为实施例2的基于金属硅化物的电极模块的主视剖视示意图；
图3为实施例2的基于金属硅化物的电极模块的侧视剖视示意图；
图4(a)、(b)分别为实施例3的余氯传感器的恒电位仪电路示意图和I－V转换电路示意图；
图5为实施例3的余氯传感器的结构示意图；
图6为实施例3的余氯传感器使用的自制参比电极模块的结构示意图；
图7为实施例3的余氯传感器使用的自制参比电极模块与商业参比电极之间的开路电压的测量结果示意图；
图8为实施例3的余氯传感器在余氯检测时，传感器输出信号与运行时间的关系；
图9为实施例3的余氯传感器在23℃环境中，在pH为6.86的水体中进行游离氯含量测试，获得的传感器输出信号与游离氯标定值的关系；
图10为实施例3的余氯传感器在23℃环境中，在pH为6.86、游离氯含量为2mg/L的水体中，连续五天每天一次测试的结果；
图11为使用5个实施例3的余氯传感器在23℃环境中，在pH为6.86的水体中进行游离氯含量的测试，传感器测量值与游离氯标定值的关系；
图12为实施例3的余氯传感器在不同pH水体中，传感器测量值与游离氯标定值的关系；
图13为实施例3的余氯传感器在测量一个具体水样的余氯测量值与温度的关系；
图14为实施例3中(RC T-RC 23)/RC 23对T-23作图；
图15(a)、(b)分别为实施例4的余氯传感器的U4A和U4B两个电压跟随器的电路示意图；
图16为实施例4的余氯传感器的结构示意图；
图17为实施例4的余氯传感器在23℃环境中，在不同pH值的测试液中进行测试，获得的传感器输出信号与pH标定值的关系示意图；
图18为使用3个实施例4的余氯传感器在23℃环境中，进行pH测试，传感器测量值与pH标定值的关系示意图；
图19为实施例4的余氯传感器在23℃环境中，在具有不同氧化还原电位的水体中进行测试，获得的传感器输出信号与ORP标定值的关系示意图；
图20(a)、(b)分别为实施例5的余氯传感器的I-V转换电路和电压跟随器的电路示意图；
图21为实施例5的余氯传感器的结构示意图；
图22为实施例5的余氯传感器在23℃环境中，在具有不同TDS的水体中进行测试，获得的传感器输出信号与TDS标定值的关系。
图中：1、金属硅化物电极；101、硅基材；102、金属硅化物层；2、壳体；3、电路板；4、金属弹簧片；5、灌封胶；6、导线；7、外壳；8、银/氯化银电极；9、银导线；10、含有饱和氯化钾的琼脂凝胶；11、多孔材料件；12、防水胶；13、基于金属硅化物的电极模块；14、参比电极模块；15、外接电路板；16、待测液。
具体实施方式
正如背景技术中介绍的，现有技术中电极的材质采用常采用金属或金属合金，使用金属或金属合金制备的电极，成本往往比较高，将该电极用于余氯传感器时，大大提高了传感器的成本，也不适合大规模生产。而且采用传统的电化学电极(电极材料为金属或金属合金)制备的余氯传感器，由于余氯本身具有很强的腐蚀性作用，所以传统的电化学电极会与余氯反应发生化学反应，影响了传统电极的电化学特性，电处理性能耐久性弱，无法稳定检测，这是本领域二三十年来都无法解决的技术难题。本申请发明人通过跨界从半导体工艺中制备新型硅化物导电陶瓷，意外发现金属硅化物具有很好的电极特性，将该金属硅化物用于制备 电极，该电极在余氯环境下发生电化学反应后仍然能够保持非常稳定的电化学特定，电处理性能耐久性强，电极不易老化，将该金属硅化物电极用于余氯传感器，能够稳定的检测余氯，突破了传统电极不能稳定检测余氯的技术难题。
下面结合说明书附图及具体实施例对本发明做进一步地描述。
实施例1
本实施例提供一种金属硅化物电极1，参见图1所示，该金属硅化物电极1为二层结构，其中一层为硅基材101，另一层为形成在硅基材101上的金属硅化物层102。
其中，金属硅化物层的厚度为10～500纳米，硅基材的厚度为0.1～1.5毫米。
该金属硅化物为选自硅化铂、硅化镍、硅化钛、硅化钴、硅化钯或硅化钨中的一种或多种的组合。
该金属硅化物电极1通过以下方法制备：
(1)在硅基材衬底上沉积金属层；
(2)将步骤(1)制备的工件置于无氧环境下进行热处理使得硅与金属反应生成金属硅化物；
(3)将步骤(2)制备的工件进行切割，制成金属硅化物电极。
其中：
步骤(1)中，
硅基材衬底的材质为多晶硅或掺杂单晶硅，其电阻率为0.01-10Ωcm。
硅基材的厚度为0.2毫米～1.5毫米，具体如可选0.5毫米。
步骤(2)中，
金属选自过渡金属，优选地，该金属为选自铂、镍、钛、钴、钯、钨中的一种或多种。具体如可选铂、钨。
金属层的厚度为10-500纳米。优选金属层的厚度为30～150纳米。具体如50纳米、100纳米。
沉积的方法为热蒸发沉积法、电子束蒸发沉积法、磁控溅射沉积法、化学镀沉积法、电镀沉积法等。
热处理的方法为采用快速退火炉(RTA，RTP)、管式退火炉、热板或真空退火炉在气氛为氮气或真空条件下，加热至100-600摄氏度热处理10-200分钟。
实施例2
本实施例提供的基于金属硅化物的电极模块，参见图2～3，包括金属硅化物电极1、壳体2、固定设置在壳体2内的电路板3及用于将电路板3与外界电路电导通的导线6，金属硅化 物电极1的一端与电路板3接触电导通，另一端为自由端，且该自由端位于壳体2之外。
该基于金属硅化物的电极模块还包括设置在壳体2内且两端分别压设在电路板3和金属硅化物电极1上使得电路板3和金属硅化物电极1能够电导通的金属弹簧片4、及填充在壳体2内的灌封胶5，以保证壳体2内部电路的防水。
壳体2内的电路板3上设置有电路，该电路除能够导通金属硅化物电极1与外界电路外，还具有检测用途。或者壳体2内的电路板3上设置的电路仅用于导通金属硅化物电极1与外界电路。
其中，壳体2为硬质塑料，材质包括但不限于ABS工程塑料、PE、PS等；
金属弹簧片4的材质可以为铜、玻铜、不锈钢等；
灌封胶5可以为AB环氧树脂等。
本例中，金属硅化物电极1的结构同实施例1，金属弹簧片4压设在金属硅化物电极1的金属硅化物层102上。
该基于金属硅化物的电极模块的制备如下：
壳体2的上端部开设有导线孔和灌胶孔、下端部开设有金属硅化物电极1插口，导线6的另一端从导线孔穿出壳体2并延伸至壳体2外，根据进一步的需要与外部电路连接，其作用是作为输出信号和/或电源接线。金属硅化物电极1的一端通过壳体2下端部的插孔进入壳体2内，需保证金属硅化物电极1与金属弹簧片4接触，金属弹簧片4的弹性提供压力使金属硅化物电极1位置固定并保证金属硅化物电极1与电路板3之间的导电情况良好；在壳体2内部填充有灌封胶5以保证内部电路的防水。
实施例3
本实施例提供余氯传感器，该余氯传感器根据安培测定原理设计，采用三电极工作方式，用于检测水体中某些容易发生氧化还原反应的待检测物含量。三个电极分别为工作电极(WE)、参比电极(RE)和对电极(CE)。在余氯传感器工作时，在工作电极和参比电极两端施加恒定的电压，以使工作电极保持一个稳定的电位势。在电催化作用下，待检测物在工作电极上发生电催化反应，通过工作电极的电流与待检测物的浓度相关，因此通过测量工作电极上的电流可以得到待检测物的含量。
该余氯传感器的电路设计如图4所示。电路工作原理：电路由恒电位仪电路、I－V转换电路组成。U4D和附属电路组成恒电位仪电路，参比电极RE的电位通过RC_REF_N施加，提供给工作电极WE一个稳定的工作电压，U4C和附属电路组成I-V转化电路，通过p2.2口进行ad采样。RE的作用就是在测量过程中提供一个稳定的电极电位，来保证工作电极的电位在测量过程中保持稳定。
参见图5所示，余氯传感器包括工作电路、2个基于金属硅化物的电极模块13、1个参比电极模块14及外接电路板15，工作电路集成在外接电路板15上，2个基于金属硅化物的电极模块13和1个参比电极模块14分别与外接电路板15电连接。
本例中，图4所示的电路设计集成在外接电路板15上，而基于金属硅化物的电极模块13的电路板3上的电路仅用于导通金属硅化物电极1与工作电路。在其他实施例中，基于金属硅化物的电极模块13的电路板3上的电路除导通金属硅化物电极1与工作电路外，还具有检测用途。
本例中，基于金属硅化物的电极模块13的结构设计同实施例2。
本例中，2个基于金属硅化物的电极模块13的金属硅化物电极中一个作为工作电极(WE)使用、另一个作为对电极(CE)使用，参比电极模块14作为参比电极(RE)使用。
本例中，参比电极模块可以使用商业参比电极，如商购的银/氯化银参比电极。也可以使用自制的参比电极模块。
参见图6所示，自制参比电极模块包括具有容纳腔的外壳7、设置在外壳7内的银/氯化银电极8、由银/氯化银电极8延伸出的银导线9、设置在外壳7内且一端穿过外壳7一端并延伸出外壳7的多孔材料件11及填充在外壳7内的含有饱和氯化钾的琼脂凝胶10，银导线9的一端穿过外壳7的另一端并延伸至外壳7外。其中，外壳7为硬质塑料，材质包括但不限于ABS工程塑料、PE、PS等；外壳内形状不限，其容积为1-50立方厘米；多孔材料件11为纤维或多孔陶瓷。
其中，外壳7可以是一个壳体和与之匹配的上盖组成，上盖开设有导线孔和注液孔，一个由银丝制成的银/氯化银电极8安装在壳体内部，其延伸出的银丝通过上盖上的导线孔伸出壳体。壳体的下端开设有液接连通孔，连通孔内插入有一段尺寸合适的多孔材料件11并且多孔材料件11的一端延伸至壳体内部，其作用是使壳体内的凝胶与外部待测溶液之间构成离子连通，同时限制壳体内氯离子向外部待测溶液的扩散速度；在壳体内，在银/氯化银电极8、多孔材料件11和壳体内壁之间填充含有饱和氯化钾的琼脂(1-5％)凝胶；上盖还开设有注液孔，通过注液孔可将热的液态溶胶注入壳体内使其填满内部空间。壳体与上盖之间、导线孔、注液孔由防水胶12密封。
银/氯化银电极8的制作方法：使用绕线机将直径为0.1-1.0毫米的银丝缠绕成内径为2.0-10毫米的螺旋形状以增大单位体积的表面积；在浓度为5％的次氯酸钠溶液中浸泡12小时得到银/氯化银电极；将该电极在12毫升含有0.01g氯化钠和0.4g聚氯乙烯的四氢呋喃溶液之中重复提拉五次，再在室温下干燥48小时，然后在5％的Nafion溶液中重复提拉五次，然后在80℃中处理1小时，最后取出冷却至室温，即得到银/氯化银电极。
本例中，使用ABS工程塑料作为外壳，外壳内尺寸为50×20×10毫米，外壳厚度为2毫米；使用的银丝直径为0.2毫米，缠绕形成的螺旋形状内径为2.5毫米；多孔材料件11为纤维条；琼脂凝胶中琼脂的质量分数为3％。
将参比电极模块的纤维浸泡在自来水中，测量参比电极模块与商业参比电极(Ag/AgCl参比电极)之间的开路电压。测量结果对浸泡时间作图如图7所示。结果发现其190小时后电位漂移量为3.85mV(相对于商业Ag/AgCl参比电极)。说明自制的参比电极模块具有稳定的电位，可以作为参比电极使用。
使用本实施例提供的余氯传感器对待测液(如待测液为水)进行检测时，参见图5所示，将作为工作电极和对电极使用的两个基于金属硅化物的电极模块13上裸露在外的金属硅化物电极和参比电极模块14的纤维条浸泡在待测液16中，由待测液16作为电解质溶液，导通形成电路回路。通过工作电极的电流可以转化为输出信号，采集频率可设置。由于电路设计具有电势校正功能，工作电极可以保持一个稳定的电位势，因此这种模块的信号可以与水的待测物含量保持良好的线性关系，据此可以得到线性拟合方程。在测量操作时，传感器在水中运行得到输出信号，通过线性拟合方程进行计算，即可得到水中的待测物含量。实际应用时还需考虑温度、pH的影响，根据实际情况进行校正。
本实施例提供的余氯传感器可用于检测水体中某些容易发生氧化还原反应的待检测物含量，比如在自来水、污水、泳池水和天然水等水体中余氯含量。不同的检测对象对应的余氯浓度范围不同(中华人民共和国卫生部.生活饮用水卫生标准[S].GB 5749-2006，2006:3-6)，如加氯消毒的管网生活饮用水中，加氯消毒30分钟后，水中游离性余氯的含量不应低于0.3mg/L；人工游泳池水中游离性余氯的标准值为0.3mg/L～0.5mg/L；用含氯洗消剂消毒后的餐具表面游离性余氯的含量应小于0.3mg/L；工业循环冷却水中余氯的测定范围为0.03mg/L～2.5mg/L。在本设计中，余氯测定范围定为0-8mg/L，这仅作为一个示例来说明传感器的功能。实际使用时，需要考虑根据具体的检测对象的要求来设置传感器的检测范围。
余氯检测的原理如下：当氯气溶解于水中，通过一系列反应产生次氯酸，次氯酸是一种弱酸，部分分解为氢离子和次氯酸离子，次氯酸在电极表面发生氧化-还原反应(式(1)和式(2))。检测运行时，需要在工作电极和参比电极两端施加一个恒定的电压，以使工作电极的电位势保持恒定，在电催化作用下，HOCl和OCl -在PtSi工作电极上发生电催化反应，电极信号与水体中的待测物含量成线性关系。
氯气溶解于水中发生的反应如下：
余氯检测的工作电极上反应方程如下：
HOCl+2e→Cl -+OH -      式(1)
OCl -+H 2O+2e→Cl -+2OH -      式(2)
将本实施例的余氯传感器用于检测水中余氯
具体以硅化铂电极作为工作电极和对电极使用，硅化铂电极的制备如下：以单面抛光、厚度0.5毫米的P型硅片为衬底，以电子束蒸发沉积法在抛光面镀铂50纳米，然后在氮气气氛中用管式退火炉进行热处理使硅和铂反应生成硅化铂，然后使用刀片切割将表面形成有硅化铂的硅基材切割成3×9.5×0.5毫米得到硅化铂电极，其中，热处理温度为400℃，热处理时间为60分钟。
基于金属硅化物的电极模块中，硅化铂电极暴露在模块外的面积为3×5毫米；壳体为ABS工程塑料；金属弹簧片为铜；灌封胶为AB环氧树脂；壳体上的电极插口的尺寸为：3.2×0.7毫米。
将两个装有硅化铂电极的基于金属硅化物的电极模块分别作为电路中的工作电极和对电极，参比电极模块作为电路中的参比电极，连接在如图4所述设计的电路上。
使用时将作为工作电极和对电极的两个基于金属硅化物的电极模块上裸露在外的硅化铂电极和参比电极模块的纤维条浸泡在待测水体中。在测量操作时，在工作电极和参比电极两端施加一个恒定的电压，以使工作电极保持在+350mV电位势(vs参比电极，即RC_REF_P-RC_REF_N＝350mV)，然后读取传感器输出信号，采集频率可设置。
下面对本实施例的余氯传感器用于检测水中余氯时的各项性能进行测试：
1、在23℃环境中，使用本实施例的余氯传感器在pH为6.86，含有不同游离氯含量(游离氯含量均使用HACH Pocket Colorimeter TM II(CHLORINE)便携式余氯计进行标定)的水体中进行信号采集，余氯传感器输出信号与运行时间的关系，如图8所示。
由图8可见，余氯传感器在不同游离氯含量的水中得到的输出信号具有明显的区分，工作60秒后信号稳定。为了采集稳定的信号提高准确性，在本测试中，余氯传感器每次测试的过程为：余氯传感器上电运行，持续工作120秒，每秒采集10个数据，采用最后10秒的数据计算平均值作为本次测试的最终采集的输出信号。
2、在23℃环境中，使用余氯传感器在pH为6.86的水体中进行游离氯含量测试，获得的传感器输出信号与游离氯标定值的关系，如图9所示。
由图9可知，在23℃环境中，pH为6.86的水中，在游离氯含量为0-8mg/L的范围内，余氯传感器的输出信号与水体中的游离氯含量进行线性拟合，方程为y＝-6.6x+869.6，R 2＝0.9951，可见线性程度较好。通过此线性拟合方程，将传感器输出信号带入计算即可得到传感器的余氯测量值。
3、余氯传感器的多次余氯测量值与误差如表1所示。
表1
余氯标定值(mg/L) 余氯测量值(mg/L) 绝对测量偏差(mg/L)
0.05412 0 0.05412
1.66644 2 0.33356
0.04379 0 0.04379
5.75828 6 0.24172
0.04366 0 0.04366
2.21797 2 0.21797
0.03462 0 0.03462
1.95444 2 0.04556
由表1可知，绝对测量偏差最大为0.33356mg/L，表明传感器的误差较小。
4、对余氯传感器进行稳定性测试：在23℃环境中，将余氯传感器持续浸泡在pH为6.86，游离氯含量为2mg/L的水体中，连续五天每天一次测试结果如图10所示，并由图10可得，Std＝8.14％。说明余氯传感器在测试时间内稳定性良好。
5、对余氯传感器进行一致性测试：在23℃环境中，将5个余氯传感器在pH为6.86的水体中进行游离氯含量的测试，传感器测量值与游离氯标定值的关系，如图11所示，结果表明余氯传感器一致性较好。
6、对余氯传感器的离子选择性进行评价：在23℃环境中，余氯传感器对水体中各种可能存在的各种干扰物质的响应(响应值单位为mg/L，把响应电流值经余氯线性拟合方程转化为对应的余氯含量)如表2所示。
表2
干扰物质 浓度 响应值(mg/L)
MgCl 2 100mM 0.03914
CuSO 4 100μM -0.02789
NH 4Cl 100mM -0.02889
KCl 300mM 0.01
CaCl 2 100mM 0.07455
ZnCl 2 100mM 0.05481
NaNO 2 100mM 0.01
以上物质涉及到的Mg 2+、Na +、K +、Ca 2+、Cu 2+、NH 4 +、Zn 2+、Cl -、SO 4 2-、NO 2 -离子的实验用量超过通常家用水的浓度范围。因此，如果使用场景为家用水，以上离子对余氯传感器的干扰可以忽略不计。
7、余氯传感器在不同pH水体中，传感器测量值与游离氯标定值的关系，如图12所示。
结果表明，传感器输出信号与待测水体的pH值有关。待测水体的pH在5～8时，测量结果不受pH影响。对于自来水和游泳池水的检测，pH都在5～8的范围内，无需补偿。
8、在一个具体水样(游离氯标定值保持在8mg/L不变)中传感器的余氯测量值与温度的关系，如图13所示。
可见余氯测量值受温度的影响较大，二者的关系近似线性。可以按下面的方法进行温度补偿：T为当前温度(℃)，RC T为温度T中的余氯测量值，RC 23为使用同一传感器检测在23℃中的同一浓度时得到的余氯测量值。将(RC T-RC 23)/RC 23对T-23作图，并进行线性拟合，就可以得到拟合公式y＝kx。其中k即为温度校正系数。那么余氯传感器的温度校正可用如下公式进行：
RC C＝RC M/[1+k(T-23)]
其中RC C为使用传感器得到的余氯浓度的温度校正值，RC M为温度校正前的传感器测量值。
具体应用在实施例中，首先将(RC T-RC 23)/RC 23对T-23(℃)作图，如图14所示。进行线性拟合得到拟合公式y＝kx。温度校正系数k＝0.03745℃ -1。将各个温度校正前的传感器测量值RC M带入公式RC C＝RC M/[1+k(T-23)]，即可得到温度校正后的余氯浓度。
实施例4
本实施例提供一种余氯传感器，该余氯传感器根据电位分析法测量原理设计，利用电极电位和溶液中某种离子的活度(或浓度等)之间的关系来测定被测物质的活度(或浓度)。它以测量电池电动势为基础，其化学电池组成是以待测液为电解质溶液，并在其中插入两只电极，一只是电极电位与被测液活度(或浓度等)有定量关系的指示电极，另一只是电位稳定不变的参比电极，通过测量该电池的电动势来确定被测物质的含量。
该余氯传感器电路设计如图15所示。电路工作原理：余氯传感器由U4A和U4B两个电压跟随器组成，在本实施例中U4B作为参比电极的供电模块，通过OUT2为参比电极提供电压，(在ORP应用中OUT2为0V，在pH应用中OUT2为1V)。U4A作为缓冲器为AD模块提供读数。OUT与指示电极相连接，通过p2.3输出给AD模块。
参见图16，余氯传感器包括工作电路、1个基于金属硅化物的电极模块13、1个参比电极模块14及外接电路板15，工作电路集成在外界电路板15上，1个基于金属硅化物的电极模块13和1个参比电极模块14分别与外接电路板15电连接。本例中，图15所示的电路设计集成在外接电路板15上，而基于金属硅化物的电极模块13的电路板3上的电路仅用于导通金属硅化物电极1与工作电路。在其他实施例中，基于金属硅化物的电极模块13的电路板3上的电路除导通金属硅化物电极1与工作电路外，还具有检测用途。
本例中，基于金属硅化物的电极模块13的结构设计同实施例2。
本例中，1个基于金属硅化物的电极模块13的金属硅化物电极作为指示电极使用，参比电极模块14作为参比电极使用。
本例中，传感器使用的参比电极模块14同实施例3。
使用本实施例余氯传感器对待测液进行检测时，参见图16所示，将作为指示电极使用的基于金属硅化物的电极模块13上裸露在外的金属硅化物电极和参比电极模块14的纤维条浸泡在待测液16(待测水体)中，由待测液作为电解质溶液，参比电极模块14可以提供稳定不变的电位，而作为指示电极的基于金属硅化物的电极模块的电动势与被测物质的含量之间具有定量关系，而基于金属硅化物的电极模块与参比电极模块之间的电势差可以通过传感器电路转化为输出信号。因此余氯传感器在待测液16中的输出信号，通过拟合方程进行计算，即可得到待测物含量。实际应用时还需考虑测试环境的影响，根据实际情况进行校正。
本实施例的余氯传感器可用于检测多种离子的含量，包括但不限于氢离子(即pH值)、氯离子、氟离子、钾离子、钙离子，还可以用于检测待测液的氧化还原电位(ORP)。
将本实施例的余氯传感器用于检测水中pH值
采用硅化钨作为指示电极的电极材料，其检测原理如下：
硅化钨表面的钨原子受到氧化形成氧化钨层，氧化钨在水中的溶解度很小。当硅化钨电极在水中浸泡时，电极表面的氧化钨会与水饱和并发生如下水解反应，生成钨离子：
Figure PCTCN2019123324-appb-000001
电极表面的钨离子有获得电子被还原成钨原子的倾向：
Figure PCTCN2019123324-appb-000002
因此硅化钨电极表面与水溶液的界面会形成电位差。根据能斯特公式：
E＝E 0+RT/nF*ln[M n+]
其中E 0为电极的标准电位，R为气体常数，T为温度，F为法拉第常数，T为绝对温度值，n为传输电子数，[M n+]为离子的浓度。那么电位差E与界面处W 6+离子浓度之间呈以下关系：
E＝E 0+RT/6F*ln[W 6+]
当达到平衡时，不同的钨离子浓度会使硅化钨电极具有不同的电极电位。又因为氧化钨在水中难溶，其溶解度与水的pH值相关，于是有：
E＝E 0-0.059pH
式中电位单位为V。电位差E可通过测量硅化钨电极与参比电极之间的开路电压得到，进而得到溶液的pH值。
具体地，以硅化钨电极作为指示电极使用，硅化钨电极的制备如下：以单面抛光、厚度0.5毫米的P型硅片为衬底，以电子束蒸发沉积法在抛光面镀钨100纳米，然后在氮气气氛中用快速退火炉(RTA)进行热处理硅和钨反应生成硅化钨，然后使用刀片切割将表面形成有硅化钨的硅基材切割成3×9.5×0.5毫米得到硅化钨电极，其中，热处理温度为400℃，热处理时间为10分钟。
基于金属硅化物的电极模块中，硅化钨电极暴露在电极模块外的面积为3×5毫米；壳体为ABS工程塑料；金属弹簧片为铜；灌封胶为AB环氧树脂；壳体上电极插口的尺寸为：3.2×0.7毫米。
将装有硅化钨电极的基于金属硅化物的电极模块13作为电路中指示电极，参比电极模块14作为电路中的参比电极，连接在如图15所述设计的电路上。
使用时将作为指示电极的基于金属硅化物的电极模块上裸露在外的硅化钨电极和参比电极模块的纤维条浸泡在待测水体中。在测量操作时，通过电路采集传感器输出信号，采集频率可设置。传感器每次测试的过程为：传感器上电运行，持续工作10秒，每秒采集10个数据，计算数据的平均值作为本次测试的最终采集的输出信号。
下面对本实施例的余氯传感器用于检测水中pH值时的各项性能进行测试：
1、在23℃环境中，使用余氯传感器在不同pH值(均使用梅特勒pH计进行标定)的测试液中进行测试，获得的传感器输出信号与pH标定值的关系，如图17所示。
由图17可知，在23℃环境中，余氯传感器在不同pH值的水中得到的输出信号具有明显的区分。在pH 5-9的范围内，传感器输出信号与水体pH值进行线性拟合，方程为y＝-52.1175x+10.1623，R 2＝0.9999，可见线性程度较好。通过此线性拟合方程，将传感器输出信号带入计算即可得到传感器的pH测量值。
2、传感器的多次pH测量值与误差如表3所示。
表3
pH标定值 pH测量值 绝对测量偏差
5.07 5.06859 0.00141
5.07 4.96306 0.10694
6 6.00877 0.00877
6 5.95697 0.04303
6.8 6.78778 0.01222
6.8 6.62661 0.17339
7.75 7.75483 0.00483
7.75 7.66849 0.08151
由表3可知，绝对测量偏差最大为0.17339，表明传感器的误差小。
3、对余氯传感器的一致性进行测试：在23℃环境中，使用3个余氯传感器进行pH测试，传感器测量值与pH标定值的关系，如图18所示。结果表明，余氯传感器一致性良好。
将本实施例的余氯传感器用于检测水中ORP
采用硅化铂电极作为ORP指示电极，其检测原理如下：
ORP指示电极可以在表面进行电子吸收或释放的电极，用来进行电位测量，而同时要求其化学性质稳定，耐受化学冲击。溶液ORP可通过测量ORP指示电极与参比电极之间的电位差获得。传感器输出信号为输出信号，反映了硅化铂电极与参比电极之间的开路电压。因此输出信号可以与待测液的ORP具有良好的线性关系，据此可以得到线性拟合方程，再通过线性拟合方程进行计算，即可得到待测液的ORP。
具体地，以硅化铂电极作为指示电极使用，硅化铂电极的制备如下：以单面抛光、厚度0.5毫米的P型硅片为衬底，以电子束蒸发方法在抛光面镀铂50纳米，然后在氮气气氛中用管式退火炉进行热处理使硅和铂反应生成硅化铂，然后使用刀片切割将硅化铂切割成3×9.5×0.5毫米得到硅化铂电极，其中，热处理温度为400℃，热处理时间为60分钟。
基于金属硅化物的电极模块中的，硅化铂电极暴露在模块外的面积为3×5毫米；壳体为ABS工程塑料；金属弹簧片为铜；灌封胶为AB环氧树脂；壳体上的电极插口的尺寸为：3.2×0.7毫米。
将装有硅化铂电极的基于金属硅化物的电极模块作为电路中ORP指示电极，参比电极模块作为电路中的参比电极，连接在如图15所设计的电路上。
使用时将作为ORP指示电极的基于金属硅化物的电极模块上裸露在外的硅化铂电极和参比电极模块的纤维条浸泡在待测水体中。在测量操作时，通过电路采集传感器输出信号，采集频率可设置。在本实施例中，余氯传感器每次测试的过程为：传感器上电运行，持续工作10秒，每秒采集10个数据，计算数据的平均值作为本次测试的最终采集的输出信号。
下面对本实施例的余氯传感器用于检测水中ORP的各项性能进行测试：
1、在23℃环境中，使用余氯传感器在具有不同氧化还原电位的水体中进行测试，获得的传感器输出信号与ORP标定值的关系，如图19所示。
由图19可知，在23℃环境中，余氯传感器在不同氧化还原电位的水体中得到的输出信号具有明显的区分。传感器输出信号与水体ORP值进行线性拟合，方程为y＝0.8682x+92.0617，R 2＝0.9542，可见线性程度较好。通过此线性拟合方程，将传感器输出信号带入计算即可得到传感器的ORP测量值。
实施例5
本实施例提供一种余氯传感器，该余氯传感器根据电阻测量法设计，采用二个电导率电极工作方式，可用于测量工业生产用水、生活用水、海水、电池电解液等的电导率以及溶解性固体总量(TDS)。
本实施例中，将两个基于金属硅化物的电极模块的金属硅化物电极作为电导率电极浸入待测溶液中，使用交流电桥法来测量中间溶液的电导率。作为电导率电极的两个基于金属硅化物的电极模块的相对位置固定，两个电极可平行放置，其金属层相对；也可将两个电极置于同一平面。
使用时将作为电导率电极的基于金属硅化物的电极模块上裸露在外的金属硅化物电极浸泡在水体中，在两个电极模块两端施加交流电，流经电极的电流值转化为传感器电路的输出信号，其与水体的电导率之间具有相关性，据此可以得到线性拟合方程。在测量操作时，传感器在待测液中运行得到输出信号，通过线性拟合方程进行计算，即可得到待测液的电导率。实际应用时还需考虑温度、pH的影响，根据实际情况进行校正。
该余氯传感器的电路设计如图20所示。电路工作原理：此设计中，U1A为I-V转换电路通过P1.6连接到ADC模块，U1B构成电压跟随器。p2.7连接到IDAC模块，通过IDAC模块为一侧电极施加0.5v—1v—0V—0.5V的电压信号。其中两个电导率电极分别连在2脚和7脚。
参见图21所示，余氯传感器包括工作电路、2个基于金属硅化物的电极模块13及外接电路板15，工作电路集成在外接电路板15上，2个基于金属硅化物的电极模块13分别与外接电路板15电连接。本例中，图20所示的电路集成在外接电路板15上，而基于金属硅化物的电极模块13的电路板3上的电路仅用于导通金属硅化物电极1与工作电路。在其他实施例中，基于金属硅化物的电极模块13的电路板3上的电路除导通金属硅化物电极1与工作电路外，还具有检测用途。
将本实施例的余氯传感器用于检测水溶液的溶解性固体总量(TDS)
水溶液的溶解性固体总量(TDS)和电导率之间具有较好的相关性，对于一般水体而言，二 者之间具有如下关系：
TDS(mg/L)＝α×K(ms)
因此当使用本实施例的余氯传感器进行TDS测量时，可通过上述公式(α取经验值)计算得到溶液的TDS。
具体地，以硅化铂电极作为电导率电极使用，硅化铂电极的制备如下：以单面抛光、厚度0.5毫米的P型硅片为衬底，以电子束蒸发沉积法在抛光面镀铂50纳米，然后在氮气气氛中用管式退火炉进行热处理使硅和铂反应生成硅化铂，然后使用刀片切割将表面形成有硅化铂的硅基材切割成3×9.5×0.5毫米得到硅化铂电极，其中，热处理温度为400℃，热处理时间为60分钟。
基于金属硅化物的电极模块中的，硅化铂电极暴露在电极模块外的面积为3×5毫米；两个电极的位置处于同一平面，两个电极间距3毫米；壳体为ABS工程塑料；金属弹簧片为铜；灌封胶为AB环氧树脂；壳体上的电极插口的尺寸为：3.2×0.7毫米。
将装有硅化铂电极的基于金属硅化物的电极模块作为电路中电导率电极，连接在如图20所述设计的电路上。
使用时将作为电导率电极的基于金属硅化物的电极模块上裸露在外的硅化铂电极浸泡在待测液16(待测水体)中，参见图21所示。在测量操作时，通过电路采集传感器输出信号，采集频率可设置。传感器每次测试的过程为：传感器上电运行，持续工作10秒，每秒采集10个数据，计算数据的平均值作为本次测试的最终采集的输出信号。
下面对本实施例的余氯传感器用于检测水溶液的溶解性固体总量(TDS)的各项性能进行测试：
1、在23℃环境中，使用余氯传感器在具有不同TDS的水体中进行测试，获得的传感器输出信号与TDS标定值的关系，如图22所示。
由图22可知，在23℃环境中，余氯传感器在具有不同TDS的水体中得到的输出信号具有明显的区分。传感器输出信号与水体TDS进行线性拟合，方程为y＝1.037x+950.407，R 2＝0.9992，可见线性程度较好。通过此线性拟合方程，将传感器输出信号带入计算即可得到传感器的TDS测量值。
2、传感器的多次TDS测量值与误差如表4所示。
表4
TDS标定值(ppm) TDS测量值(ppm) 绝对测量偏差(ppm) 相对误差(％)
65 64.21697 0.78303 1.20466
119 123.0405 4.0405 3.39538
868 860.74542 7.23458 0.83348
122 123.0405 1.0405 0.85287
868 865.56702 2.43298 0.2803
122 123.93346 3.93346 3.22415
由表4可见，相对误差最大值为3.4％，表明传感器的误差较小。
需要说明的是，在组装具体余氯传感器时，可以将2个基于金属硅化物的电极模块和1个参比电极模块组装成一个余氯传感器，然后通过设计电路，在不同的时间，切换不同的工作模式(如2个基于金属硅化物的电极模块和1个参比电极模块同时工作的工作模式(如实施例3的三电极工作方式)、1个基于金属硅化物的电极模块和1个参比电极模块同时工作的工作模式(实施例4的工作方式)、2个基于金属硅化物的电极模块同时工作的工作模式(实施例5的工作方式))，如此就可以实现1个余氯传感器可以对水体的多个指标进行监控。而上述组合仅是本发明的一种组合方式，也可以根据需要进行其他的组合方式。
上述实施例只为说明本发明的技术构思及特点，其目的在于让熟悉此项技术的人士能够了解本发明的内容并据以实施，并不能以此限制本发明的保护范围。凡根据本发明精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围之内。

Claims (20)

  1. 一种基于电化学原理的余氯传感器，包括工作电路以及多个电极，其特征在于：所述多个电极中至少有一个所采用的电极材料包括金属硅化物。
  2. 根据权利要求1所述的基于电化学原理的余氯传感器，其特征在于：所述多个电极中至少有工作电极和对电极，所述工作电极和/或对电极采用的电极材料包括金属硅化物。
  3. 根据权利要求1或2所述的基于电化学原理的余氯传感器，其特征在于：所述多个电极中有一个为不含金属硅化物的参比电极。
  4. 根据权利要求3所述的基于电化学原理的余氯传感器，其特征在于：所述参比电极为银/氯化银电极。
  5. 根据权利要求1或2所述的基于电化学原理的余氯传感器，其特征在于：所述多个电极中至少有一个所采用的电极材料为二层结构或三层结构，当所述电极材料为二层结构时，其中一层由所述金属硅化物构成，另一层由硅构成；当所述电极材料为三层结构时，中间层由硅构成，位于中间层两侧的外层由所述金属硅化物构成。
  6. 根据权利要求5所述的基于电化学原理的余氯传感器，其特征在于：所述的二层结构或三层结构中，由金属硅化物构成的层的厚度为10～500纳米，由硅构成的层的厚度为0.1～1.5毫米。
  7. 根据权利要求5所述的基于电化学原理的余氯传感器，其特征在于：所述的二层结构或三层结构通过以硅基材为衬底，沉积金属层后，经热处理形成。
  8. 根据权利要求7所述的基于电化学原理的余氯传感器，其特征在于：所述的硅基材的厚度为0.1～1.5毫米，沉积的金属层的厚度为10～500纳米。
  9. 根据权利要求1或2所述的基于电化学原理的余氯传感器，其特征在于：所述的金属硅化物中的金属选自过渡金属。
  10. 根据权利要求9所述的基于电化学原理的余氯传感器，其特征在于：所述的金属硅化物中的金属为选自铂、镍、钛、钴、钯、钨中的一种或多种。
  11. 根据权利要求1或2所述的基于电化学原理的余氯传感器，其特征在于：所述的金属硅化物为选自硅化铂、硅化镍、硅化钛、硅化钴、硅化钯或硅化钨中的一种或多种的组合。
  12. 根据权利要求1所述的基于电化学原理的余氯传感器，其特征在于：所述多个电极中有一个、二个或三个所采用的电极材料分别包括所述金属硅化物。
  13. 根据权利要求1或2所述的基于电化学原理的余氯传感器，其特征在于：所述余氯传感器还包括辅助连接机构，用于将所述电极材料包含金属硅化物的电极与所述工作电路导通。
  14. 根据权利要求13所述的基于电化学原理的余氯传感器，其特征在于：所述的辅助连 接机构包括壳体、位于所述壳体内的电路板及用于将所述电路板与所述工作电路导通的导线，所述电极材料包含金属硅化物的电极的一端与所述电路板接触电导通，另一端为自由端，且该自由端位于所述壳体之外。
  15. 根据权利要求14所述的基于电化学原理的余氯传感器，其特征在于：所述的辅助连接机构还包括设置在所述壳体内且两端分别压设在所述电路板和所述电极材料包含金属硅化物的电极上使得所述电路板和所述电极材料包含金属硅化物的电极能够电导通的金属弹簧片。
  16. 根据权利要求14所述的基于电化学原理的余氯传感器，其特征在于：所述余氯传感器还包括填充在所述壳体内的灌封胶，以保证所述壳体内部电路的防水。
  17. 根据权利要求14所述的基于电化学原理的余氯传感器，其特征在于：所述壳体内的电路板上设置有电路，所述电路除导通所述电极与所述工作电路外，还具有检测用途。
  18. 一种如权利要求1至17中任一项权利要求所述的基于电化学原理的余氯传感器用于检测体系中的余氯含量、pH值、氟离子含量、钾离子含量、钙离子含量，体系的氧化还原电位、体系的电导率或体系中溶解性固体总量的用途。
  19. 根据权利要求18所述的用途，其特征在于：所述体系为水系体系或电池电解液体系。
  20. 根据权利要求19所述的用途，其特征在于：所述水系体系包括工业生产用水、生活用水、海水、污水、泳池水和天然水。
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