阅读说明：本技术 一种废水中铊浓度的自动测定仪器及自动测定方法 (Automatic measuring instrument and automatic measuring method for thallium concentration in wastewater ) 是由 陈阳 陈晓磊 吴宜潜 李威桓 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种废水中铊浓度的自动测定仪器及自动测定方法,所述自动测定仪器可以在待测样品被抽取至检测池后先对待测样品的导电情况进行检测以评估水样的复杂情况,只有在确定待测样品为简单水样后才启用三电极系统进行检测,确保了检测结果的可靠性和准确度。另外,整个进样、检测过程自动化进行,无需人为干预,仪器的整体结构相对较为简单,维护成本较低,仅需定期对检测池进行清洗即可实现反复使用,便于实现广泛布点监控。(The invention discloses an automatic measuring instrument and an automatic measuring method for thallium concentration in wastewater, wherein the automatic measuring instrument can firstly detect the conductivity of a sample to be detected after the sample to be detected is extracted into a detection pool so as to evaluate the complex condition of a water sample, and only after the sample to be detected is determined to be a simple water sample, a three-electrode system is started for detection, so that the reliability and the accuracy of a detection result are ensured. In addition, the whole sample introduction and detection process is carried out automatically, manual intervention is not needed, the overall structure of the instrument is relatively simple, the maintenance cost is low, repeated use can be realized only by cleaning the detection cell regularly, and wide point distribution monitoring is convenient to realize.)

1. The automatic measuring instrument for the thallium concentration in the wastewater is characterized by comprising a detection cell (5), a power system, an auxiliary electrode (2), a working electrode (6), a reference electrode (1), an electrolytic rod electrode (4) and a control system, wherein the auxiliary electrode (2), the working electrode (6), the reference electrode (1) and the electrolytic rod electrode (4) are detachably connected with the detection cell (5) and communicated to the detection cell (5);

the power system quantitatively extracts a sample to be detected into the detection cell (5), detects the conductivity of the sample to be detected through the auxiliary electrode (2) and the electrolytic rod electrode (4), detects a signal value of thallium in the sample to be detected by adopting a three-electrode system consisting of the auxiliary electrode (2), the working electrode (6) and the reference electrode (1) if the conductivity of the sample to be detected meets a preset condition, and calculates the sample concentration of thallium according to the detected signal value.

2. The apparatus for automatically measuring the thallium concentration in the wastewater according to claim 1, wherein if the conductivity in the sample to be measured does not satisfy the predetermined condition, the auxiliary electrode (2) and the electrolysis rod electrode (4) are used to form a cathode and an anode, and a voltage is applied between the cathode and the anode to electrolyze the sample to be measured, and the conductivity of the sample to be measured is continuously detected, after the electrolysis is completed, the power system is controlled to operate to discharge the precipitate, the clear sample is retained, the signal value of thallium in the clear sample is quantified by a three-electrode method, and the sample concentration of thallium is calculated based on the detected signal value of thallium.

3. The apparatus for automatically determining the thallium concentration in the wastewater of claim 2, further comprising a stirring device (3) connected to the control system, wherein the control system is configured to control the stirring device (3) to stir the sample to be measured during the electrolysis and the detection.

4. The apparatus for the automatic determination of thallium concentration in wastewater of claim 2, characterized in that a thermostat device is further arranged in the detection cell (5), said thermostat device being connected to a control system, said control system being further adapted to control the operating state of said thermostat device in response to temperature requirements of the electrolysis or three-electrode detection.

5. The automatic thallium concentration measuring apparatus of claim 2, wherein the detection tank (5) comprises a pre-treatment sub-tank and a detection sub-tank, the pre-treatment sub-tank is communicated with the detection sub-tank, a solenoid valve is arranged on a pipeline communicated with the pre-treatment sub-tank, the solenoid valve is connected with a control system, the pre-treatment sub-tank and the detection sub-tank are both connected with the power system, before detection, the control system controls the power system to deliver a sample to be detected into the pre-treatment sub-tank, controls the power system to work after electrolysis is completed to discharge precipitates, then controls the solenoid valve to open, delivers a clear sample to the detection sub-tank, and performs three-electrode detection in the detection sub-tank.

6. An automatic measuring method of thallium concentration in wastewater using the automatic measuring apparatus according to any one of claims 1 to 5, characterized by comprising:

quantitatively extracting a sample to be detected into a detection pool (5);

detecting the conductivity of a sample to be detected;

and if the electric conduction condition of the sample to be detected meets the preset condition, quantifying the signal value of thallium in the sample to be detected by adopting a three-electrode method, and calculating the sample concentration of thallium according to the detected signal value of thallium.

7. The method of claim 6, wherein if the conductivity of the sample does not satisfy the predetermined condition, the method further comprises:

an auxiliary electrode (2) and an electrolytic rod electrode (4) are adopted to form a cathode and an anode, voltage is applied between the cathode and the anode to electrolyze a sample to be detected, and the conduction condition of the sample to be detected is continuously detected;

discharging the precipitate after the electrolysis is finished, and reserving a clear sample;

and (3) quantifying the thallium signal value in the clear sample by adopting a three-electrode method, and calculating to obtain the thallium sample concentration according to the detected thallium signal value.

8. The method of automatically determining the thallium concentration in the wastewater of claim 7, wherein during the electrolysis, the end of the electrolysis is controlled based on a preset electrolysis time; or detecting the conductive current of the sample to be detected in real time in the electrolysis process, and controlling the electrolysis process to be finished when the current fluctuation of the conductive current of the sample to be detected in a preset time period is detected to be not more than a threshold value.

9. The method of automatically determining the concentration of thallium in wastewater of claim 7, wherein the sample to be tested is agitated during the electrolysis and detection.

10. The method of automatically determining the thallium concentration in the wastewater of claim 7, wherein the temperature of the sample to be measured is controlled to be kept stable according to the temperature requirements during the electrolysis process and the three-electrode measurement process.

Technical Field

The invention relates to the technical field of water quality detection, in particular to an automatic measuring instrument and an automatic measuring method for thallium in wastewater.

Background

Thallium is a highly toxic substance, has accumulation property, is a strong nerve poison, has a main toxicity effect on human bodies, is caused by nerve toxicity, can cause functional damage to multiple organs such as kidney, liver and the like, and has far higher toxicity than arsenic, mercury, cadmium and the like. With the rapid development of industries such as smelting, chemical engineering and the like, a large amount of heavy metals and metalloids enter atmosphere, water, sediments, soil and biological environments through various ways such as mining, metal smelting, metal processing and the like, and serious environmental pollution is caused. Therefore, there is a need for automatic monitoring of thallium, a highly toxic substance.

In the current automatic monitoring application, part of instrument companies in the market adopt the integration of large laboratory ICP-MS equipment on board or other modes to be applied to automatic monitoring and fixed point location monitoring on emergency sites, but due to the limitation of ICP-MS automatic monitoring, the instrument cost and the operating cost are high, the applicability to high organic matters and/or high-salt wastewater is poor, the instrument is not suitable for restriction bottlenecks such as wide distribution monitoring and the like, and the market urgently needs to develop a full-automatic analysis thallium analysis instrument with simple structure and low cost to meet the automatic monitoring requirements in the current stage, particularly the measurement of thallium in wastewater. In addition, currently, thallium detection is easily affected by salinity and organic matters, and when wastewater with high organic matter content and/or wastewater with higher salinity are encountered, the accuracy of a thallium content measurement result is poor. In a laboratory, waste water with high organic matter content is pretreated by adopting a strong acid and evaporation method to remove organic matters, but the method is difficult to realize automatic operation, has great harm and is easy to damage the health of operators.

Disclosure of Invention

The invention provides an automatic measuring instrument and an automatic measuring method for thallium in wastewater, which aim to solve the defects of the prior art.

According to one aspect of the invention, an automatic measuring instrument for thallium concentration in wastewater is provided, which comprises a detection cell, a power system, an auxiliary electrode, a working electrode, a reference electrode, an electrolytic rod electrode and a control system, wherein the auxiliary electrode, the working electrode, the reference electrode and the electrolytic rod electrode are detachably connected with the detection cell and communicated with the detection cell;

and the power system quantitatively extracts a sample to be detected into the detection pool, detects the conduction condition of the sample to be detected through the auxiliary electrode and the electrolytic rod electrode, detects the signal value of thallium in the sample to be detected by adopting a three-electrode system consisting of the auxiliary electrode, the working electrode and the reference electrode if the conduction condition of the sample to be detected meets a preset condition, and calculates the sample concentration of thallium according to the detected signal value.

Further, if the conductivity of the sample to be detected does not meet the preset conditions, an auxiliary electrode and an electrolytic rod electrode are adopted to form a cathode and an anode, voltage is applied between the cathode and the anode to electrolyze the sample to be detected, the conductivity of the sample to be detected is continuously detected, after the electrolysis is completed, the power system is controlled to work to discharge precipitates, a clear sample is reserved, the signal value of thallium in the clear sample is quantified through a three-electrode method, and the sample concentration of thallium is calculated according to the detected signal value of thallium.

Further, the device also comprises a stirring device connected with the control system, and the control system is used for controlling the stirring device to stir the sample to be detected in the electrolysis and detection processes.

Further, a constant temperature device is arranged in the detection pool and connected with a control system, and the control system is further used for controlling the working state of the constant temperature device according to the temperature requirement of electrolysis or three-electrode detection.

Further, the detection pool comprises a pre-treatment sub-pool and a detection sub-pool, the pre-treatment sub-pool is communicated with the detection sub-pool, an electromagnetic valve is arranged on a pipeline communicated with the pre-treatment sub-pool and the detection sub-pool, the electromagnetic valve is connected with a control system, the pre-treatment sub-pool and the detection sub-pool are both connected with the power system, the control system controls the power system to convey a sample to be detected into the pre-treatment sub-pool before detection, controls the power system to work after electrolysis is completed so as to discharge precipitates, controls the electromagnetic valve to be opened, conveys clear samples into the detection sub-pool, and performs three-electrode detection in the detection sub-pool.

In addition, the invention also provides an automatic measuring method for thallium concentration in wastewater, which adopts the automatic measuring instrument and comprises the following contents:

quantitatively extracting a sample to be detected into a detection pool;

detecting the conductivity of a sample to be detected;

and if the electric conduction condition of the sample to be detected meets the preset condition, quantifying the signal value of thallium in the sample to be detected by adopting a three-electrode method, and calculating the sample concentration of thallium according to the detected signal value of thallium.

Further, if the conduction condition in the sample to be tested does not meet the preset condition, the method further comprises the following steps:

adopting an auxiliary electrode and an electrolytic rod electrode to form a cathode and an anode, applying voltage between the cathode and the anode to electrolyze a sample to be detected, and continuously detecting the conduction condition of the sample to be detected;

discharging the precipitate after the electrolysis is finished, and reserving a clear sample;

and (3) quantifying the thallium signal value in the clear sample by adopting a three-electrode method, and calculating to obtain the thallium sample concentration according to the detected thallium signal value.

Further, in the electrolysis process, controlling the electrolysis process to be finished based on the preset electrolysis time; or detecting the conductive current of the sample to be detected in real time in the electrolysis process, and controlling the electrolysis process to be finished when the current fluctuation of the conductive current of the sample to be detected in a preset time period is detected to be not more than a threshold value.

Further, the sample to be tested is agitated during the electrolysis and detection processes.

Further, the temperature of the sample to be detected is controlled to be kept stable according to the temperature requirement in the electrolysis process and the three-electrode detection process.

The invention has the following effects:

the automatic measuring instrument for the thallium concentration in the wastewater has a simple structure and low cost, and utilizes the electrolytic rod electrode and the auxiliary electrode in the three-electrode system to detect the conduction condition of the sample to be measured containing organic matters and salinity interference so as to evaluate whether the sample to be measured needs to be subjected to electrolytic pretreatment, thereby ensuring the accuracy of the test result of the instrument and improving the working efficiency of the instrument. In addition, the whole sample introduction and detection process is carried out automatically, manual intervention is not needed, the overall structure of the instrument is relatively simple, the maintenance cost is low, repeated use can be realized only by cleaning the detection cell regularly, and wide point distribution monitoring is convenient to realize.

In addition, the method for automatically measuring the thallium concentration in wastewater of the present invention also has the above-described advantages.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view showing the structure of an apparatus for automatically measuring the thallium concentration in wastewater according to a preferred embodiment of the present invention.

FIG. 2 is a schematic flow chart showing a method for automatically measuring the thallium concentration in the wastewater according to another embodiment of the present invention.

FIG. 3 is a schematic flow chart showing another embodiment of the method for automatically measuring the thallium concentration in wastewater according to the present invention.

Description of the reference numerals

1. A reference electrode; 2. an auxiliary electrode; 3. a stirring device; 4. an electrolytic rod electrode; 5. a detection cell; 6. a working electrode; 7. a power pump; 8. a liquid level metering device; 9. valve way auto-change over device.

Detailed Description

The embodiments of the invention will be described in detail below with reference to the accompanying drawings, but the invention can be embodied in many different forms, which are defined and covered by the following description.

As shown in FIG. 1, the preferred embodiment of the present invention provides an automatic measuring instrument for thallium concentration in wastewater, which comprises a detection cell 5, a power system, an auxiliary electrode 2, a working electrode 6, a reference electrode 1, an electrolytic rod electrode 4 and a control system, wherein the auxiliary electrode 2, the working electrode 6, the reference electrode 1 and the electrolytic rod electrode 4 are detachably connected with the detection cell 5 and communicated with the detection cell 5. The power system quantitatively extracts a sample to be detected into the detection pool 5, detects the conduction condition of the sample to be detected through the auxiliary electrode 2 and the electrolytic rod electrode 4, detects the signal value of thallium in the sample to be detected by adopting a three-electrode system consisting of the auxiliary electrode 2, the working electrode 6 and the reference electrode 1 if the conduction condition of the sample to be detected meets a preset condition, and calculates the sample concentration of thallium according to the detected signal value of thallium.

It can be understood that the automatic measuring instrument for the thallium concentration in the wastewater has simple structure and lower cost. The method comprises the steps of detecting the conductive condition of a sample to be detected containing organic matters and salinity interference by utilizing an electrolytic rod electrode 4 and an auxiliary electrode 2 in a three-electrode system to evaluate whether the sample to be detected needs to be subjected to electrolytic pretreatment, starting the three-electrode system to detect the thallium content in the sample to be detected only when the conductive condition of the sample to be detected meets a preset condition, avoiding the problem of low accuracy of the thallium detection result of the sample to be detected caused by complex water sample condition, and accurately judging whether the organic matters and salt substances exist in the sample to be detected and further interfere the detection result. Therefore, the accuracy of the test result of the instrument is ensured, and the working efficiency of the instrument is improved. In addition, the whole sample introduction and detection process is carried out automatically, manual intervention is not needed, the overall structure of the instrument is relatively simple, the maintenance cost is low, repeated use can be realized only by cleaning the detection cell 5 regularly, and wide point distribution monitoring is convenient to realize.

It can be understood that the detection pool 5 is made of acid-base-resistant and high-temperature-resistant materials, and the detection pool 5 preferably adopts a quartz glass detection pool. The overall structure of the detection cell 5 is a four-fork structure, the auxiliary electrode 2, the working electrode 6, the reference electrode 1 and the electrolytic rod electrode 4 extend out of a sample to be detected in the detection cell 5 from one fork, and the positions of the auxiliary electrode 2, the reference electrode 1 and the electrolytic rod electrode 4 can be exchanged with each other, which is not limited specifically. Preferably, the bottom of the detection cell 5 is provided with a through hole matched with the shape of the working electrode 6, and the working electrode 6 is detachably connected with the detection cell 5 through the through hole. Further preferably, the detection surface of the working electrode 6 is flush with the bottom of the detection cell 5, when the detection is completed, after the detection cell 5 is cleaned and emptied, water drops still remain on the surface of the working electrode 6 to form a liquid seal, so that the surface of the working electrode 6 is prevented from being oxidized due to contact with air, and the accuracy of the next test result is not affected.

It can be understood that the power system specifically includes power pump 7, liquid level metering device 8 and valve way auto-change over device 9, liquid level metering device 8 is connected with power pump 7, valve way auto-change over device 9 respectively, valve way auto-change over device 9 still is connected with detection pond 5, outside stock solution device respectively. The valve path switching device 9 includes a plurality of valve paths and can switch among the plurality of valve paths, and the external liquid storage device stores samples to be tested, reagents, standard samples, pure water, etc. respectively, and different liquids can be extracted into the detection cell 5 through different valve paths in the valve path switching device 9. For example, the valves DCF3 and DCF8 of the valve switching device 9 serve as reagent channels, the valve DCF2 serves as a pure water channel, the valve DCF7 serves as a waste liquid discharge channel, and the remaining valves serve as flow channels for different liquids. Wherein, the power pump 7 can adopt a plunger pump or a peristaltic pump. For example, the power pump 7 adopts a plunger pump, before the detection is started, the control system controls the plunger pump to start working, a sample to be detected is extracted from an external liquid storage device, the volume of the extracted sample to be detected is fed back in real time through the liquid level metering device 8, infrared geminate transistors are installed at different positions in the liquid level metering device 8, the volume corresponding to each liquid level is known, and therefore the volume of the extracted liquid can be reflected through the detection of the liquid level. And the control system controls the working state of the plunger pump according to the liquid level feedback signal of the liquid level metering device 8, and controls the plunger pump to stop working when the volume of the extracted sample to be detected reaches a preset value, so that quantitative extraction is realized. After a certain amount of sample to be detected is extracted into the detection cell 5, the control system measures the conduction condition of the sample to be detected to evaluate the complex condition of the sample to be detected, specifically, the auxiliary electrode 2 and the electrolytic rod electrode 4 are used as detection electrodes to detect the conduction condition, if the conduction condition of the sample to be detected meets a preset condition, it can be understood that when the conduction current of the sample to be detected is greater than or equal to a preset threshold value, for example, greater than or equal to 0.1A, and of course, the threshold value can be set according to the actual condition, and is not specifically limited, the sample to be detected is determined to be a simple water sample, the salt and organic matters in the sample to be detected are few, and the influence on the determination result is small, even can be ignored. And (3) directly adopting a three-electrode method to quantify the signal value of thallium in the sample to be detected aiming at the simple water sample, and calculating by the control system according to the detected signal value of thallium and the signal value-concentration curve to obtain the sample concentration of thallium. The specific implementation process of the three-electrode method belongs to the prior art, and is not described herein again. In addition, other liquids such as reagents and standard samples required in the three-electrode method detection process can be conveyed by controlling the corresponding valve path of the valve path switching device 9 to be opened.

It can be understood that the automatic measuring instrument for thallium concentration in wastewater of the present embodiment can control the operating state of the power system based on the liquid level feedback result of the liquid level metering device 8, thereby realizing quantitative extraction. And after the sample to be detected is extracted to the detection pool 5, the conductivity of the sample to be detected is detected to evaluate the complex condition of the water sample, and the three-electrode system is started for detection only after the sample to be detected is determined to be a simple water sample, so that the reliability and the accuracy of the detection result are ensured. In addition, the whole sample introduction and detection process is carried out automatically, manual intervention is not needed, the overall structure of the instrument is relatively simple, the maintenance cost is low, repeated use can be realized only by cleaning the detection cell 5 regularly, and wide point distribution monitoring is convenient to realize.

It is understood that in other embodiments of the present invention, the power system may adopt a peristaltic pump as the power pump 7, and the peristaltic pump may be used in combination with the valve switching device 9 to achieve quantitative pumping, since the peristaltic pump itself can monitor the flow rate.

It can be understood that, if the conduction condition in the sample to be detected does not satisfy the preset condition, it can be understood that when the conduction current in the sample to be detected is smaller than the threshold, for example, smaller than 0.1A, this means that the sample to be detected is relatively complex, the sample to be detected has relatively high salinity and/or relatively high organic matter content, and the influence on the detection result is relatively large, and if the three-electrode system is directly used for detection, the obtained detection result is inaccurate, in other words, the detected test value cannot reflect the true concentration value of thallium in the sample to be detected. Therefore, the auxiliary electrode 2 and the electrolytic rod electrode 4 are adopted to form a cathode and an anode, wherein the auxiliary electrode 2 is used as the cathode, the electrolytic rod electrode 4 is used as the anode, the electrolytic rod electrode 4 can be a graphite electrode or a titanium rod electrode, voltage is applied between the cathode and the anode to electrolyze a sample to be detected, and the conduction condition of the sample to be detected is continuously detected; for example, 30V direct current voltage is applied between the auxiliary electrode 2 and the electrolysis rod electrode 4 to electrolyze the sample to be detected, in the electrolysis process, organic matters and chloride ions in the sample to be detected are oxidized and decomposed, and the concentration of the organic matters and the chloride ions can be reduced by more than 10 times by adopting an electrolysis mode, so that a complex water sample is treated into a simple water sample. After the electrolysis is completed, the control system controls the working state of the power system to discharge the precipitate, for example, the precipitate under natural sedimentation is discharged through a valve DCF11 communicated with the detection cell 5, a clear sample is reserved, the clear sample at the moment can be regarded as a simple water sample, the signal value of thallium in the clear sample is quantified through a three-electrode method, and the sample concentration of thallium is calculated according to the detected signal value of thallium. Wherein, the electrolysis time can be preset according to an empirical value, namely the electrolysis process is stopped after the preset electrolysis time is reached; or detecting the conducting current of the sample to be detected in real time in the electrolysis process, and controlling the electrolysis process to be finished when detecting that the current fluctuation of the conducting current of the sample to be detected in a preset time period does not exceed a threshold value, for example, the change of the electrolysis current does not exceed 0.05A in continuous 60 s.

It can be understood that, according to the automatic determination instrument, after the situation of a water sample is detected to be complicated based on the conduction situation of the sample to be detected, the cathode and the anode are formed by the electrolysis rod electrode 4 and the auxiliary electrode 2, the sample to be detected is electrolyzed in an electrolysis mode, so that the concentration of organic matters and the concentration of chloride ions in the complicated water sample are reduced by more than 10 times, the complicated water sample is preprocessed into a simple water sample, and then the three-electrode method is adopted for detection, so that the preprocessing of the complicated water sample is realized. In addition, the three-electrode system and the electrolysis electrode share one electrode, so that the number of the whole electrodes is reduced, and in addition, the three-electrode system and the pretreatment system are integrally designed, namely the pretreatment process and the detection process are carried out in the detection cell 5, so that the miniaturization of the whole structure of the instrument is convenient to realize.

It will be appreciated that the automated measuring device further comprises a stirring device 3 connected to the control system for controlling the stirring device 3 to stir the sample to be measured during the electrolysis and detection processes. In the electrolysis process, can stir the sample that awaits measuring constantly through agitating unit 3, promote the water sample flow to improve the electrolysis effect. The stirring device 3 can be arranged independently, or the stirring rod of the stirring device 3 and the electrode can be arranged together, for example, the stirring rod adopts a hollow design, the reference electrode 1 is embedded in the stirring rod, and a through hole is formed at the position where the stirring rod is contacted with the liquid level, so that the reference electrode 1 can be contacted with a sample to be detected to realize detection.

In addition, a constant temperature device is further arranged in the detection pool 5 and connected with a control system, and the control system is further used for controlling the working state of the constant temperature device according to the temperature requirement of electrolysis or three-electrode detection. The constant temperature device can accurately control the temperature to +/-0.1 ℃, the maximum heating temperature can reach 100 ℃, and the requirements of pretreatment high temperature of complex samples in wastewater and constant temperature of sample detection can be met.

In addition, in other embodiments of the present invention, the detection cell 5 includes a pre-treatment sub-cell and a detection sub-cell, the pre-treatment sub-cell is communicated with the detection sub-cell, and a pipeline communicating the pre-treatment sub-cell and the detection sub-cell is provided with an electromagnetic valve, the electromagnetic valve is connected with a control system, both the pre-treatment sub-cell and the detection sub-cell are connected with the valve switching device 9, before detection, the control system firstly controls the valve switching device 9 to deliver a sample to be detected into the pre-treatment sub-cell, after electrolysis is completed, controls the power system to work to discharge precipitates, then controls the electromagnetic valve to open, delivers a clear sample to the detection sub-cell, and performs three-electrode detection in the detection sub-cell. The detection pool 5 is divided into the pretreatment sub-pool and the detection sub-pool, the pretreatment process of the complex water sample is carried out in the pretreatment sub-pool, and after the precipitate is discharged completely, the sample to be detected is introduced into the detection sub-pool to carry out three-electrode detection, so that the accuracy of the detection result is further ensured. It can be understood that when the current treatment and detection adopts the cell-dividing design, two electrodes are required to be arranged in the pre-treatment cell to detect the conduction condition of the sample to be detected, and three electrodes are required to be arranged in the detection cell to form a three-electrode system; or an electrolytic rod electrode is arranged in the pretreatment tank, three electrodes are arranged in the detection tank to form a three-electrode system, and the pretreatment sub-tank is communicated with the detection sub-tank when the conductivity of the sample to be detected is detected or the sample to be detected is subjected to electrolytic pretreatment.

In addition, as shown in fig. 2, another embodiment of the present invention further provides an automatic measuring method for thallium concentration in wastewater, preferably using the automatic measuring apparatus as described above, comprising the following steps:

step S1: quantitatively extracting a sample to be detected into a detection pool 5;

step S2: detecting the conductivity of a sample to be detected;

step S3: and if the electric conduction condition of the sample to be detected meets the preset condition, quantifying the signal value of thallium in the sample to be detected by adopting a three-electrode method, and calculating the sample concentration of thallium according to the detected signal value of thallium.

After the instrument is started, the control system controls the power system to start working so as to quantitatively draw a sample to be detected from the external liquid storage device into the detection cell 5. Then, the control system performs the detection of the conductive current by using the auxiliary electrode 2 and the electrolytic rod electrode 4 as the detection electrodes, and if the conductive condition in the sample to be detected meets the preset condition, it can be understood that when the conductive current in the sample to be detected is greater than or equal to a preset threshold value, for example, greater than or equal to 0.1A, the sample to be detected is determined to be a simple water sample, and the salts and organic matters in the sample to be detected are less, so that the influence on the measurement result is less, or even can be ignored. And (3) directly adopting a three-electrode method to quantify the signal value of thallium in the sample to be detected aiming at the simple water sample, and calculating by the control system according to the detected signal value of thallium and the signal value-concentration curve to obtain the sample concentration of thallium.

It can be understood that the method for automatically determining the concentration of thallium in wastewater of the embodiment can realize quantitative extraction of a water sample, and after the sample to be detected is extracted to the detection pool 5, the conductivity of the sample to be detected is detected first to evaluate the complex condition of the water sample, and only after the sample to be detected is determined to be a simple water sample, the three-electrode system is started to detect, so that the reliability and accuracy of the detection result are ensured. In addition, the whole sample introduction and detection process is carried out automatically without human intervention.

In addition, as shown in fig. 3, if the conduction condition in the sample to be measured does not satisfy the preset condition, it can be understood that when the conduction current in the sample to be measured is less than the threshold value, the automatic measuring method further includes the following steps:

step S4: adopting an auxiliary electrode 2 and an electrolytic rod electrode 4 to form a cathode and an anode, applying voltage between the cathode and the anode to electrolyze a sample to be detected, and continuously detecting the conduction condition of the sample to be detected;

step S5: discharging the precipitate after the electrolysis is finished, and reserving a clear sample;

step S6: and (3) quantifying the thallium signal value in the clear sample by adopting a three-electrode method, and calculating to obtain the thallium sample concentration according to the detected thallium signal value.

If the conduction condition of the sample to be detected does not meet the preset condition, it can be understood that when the conduction current of the sample to be detected is less than the threshold value, for example, less than 0.1A, the sample to be detected is relatively complex, the salinity and/or organic matter content of the sample to be detected is relatively high, and the influence on the detection result is relatively large, and if the three-electrode system is directly adopted for detection, the obtained detection result is prone to error. Therefore, the present embodiment adopts the auxiliary electrode 2 and the electrolysis rod electrode 4 to form a cathode and an anode, and applies a voltage between the cathode and the anode to electrolyze the sample to be tested, and continuously detects the conductivity of the sample to be tested. For example, 30V direct current voltage is applied between the reference electrode 1 and the electrolytic rod electrode 4 to electrolyze the sample to be detected, in the electrolytic process, organic matters and chloride ions in the sample to be detected are oxidized and decomposed, and the concentration of the organic matters and the chloride ions can be reduced by more than 10 times by adopting an electrolytic mode, so that a complex water sample is treated into a simple water sample. After the electrolysis is completed, the control system controls the working state of the power system and the valve path switching device 9 to discharge the precipitate, for example, the precipitate in natural sedimentation is discharged through a valve DCF11 communicated with the detection cell 5, a clear sample is reserved, the clear sample can be regarded as a simple water sample, the signal value of thallium in the clear sample is quantified through a three-electrode method, and the sample concentration of thallium is calculated according to the detected signal value of thallium.

It can be understood that, after the water sample condition is detected to be complicated based on the conductivity of the sample to be detected, in other words, when the content of organic matters and salinity substances in the sample to be detected can affect the accurate measurement of the thallium concentration in the sample to be detected, the anode and the cathode are formed by the electrode 4 of the electrolytic rod and the auxiliary electrode 2 in the three-electrode system, the sample to be detected is pretreated in an electrolytic way, so that the concentration of the organic matters and the concentration of chloride ions in the complex water sample are reduced to the test result that the thallium concentration in the sample to be detected is not affected, the complex water sample is pretreated into a simple water sample, and then the three-electrode method is adopted for detection, thereby realizing the pretreatment of the complex water sample.

Wherein, in the electrolysis process, the electrolysis process is controlled to be finished based on the preset electrolysis time; or, detecting the conductivity of the sample to be detected in real time in the electrolysis process, and controlling the electrolysis process to be finished when detecting that the current fluctuation of the conductive current of the sample to be detected in a preset time period does not exceed a threshold value, for example, the change of the electrolysis current does not exceed 0.05A in continuous 60 s.

It is understood that, as a preferable mode, the step S4 further includes the following steps:

and stirring the sample to be detected in the electrolysis and detection processes. In the electrolysis process, the sample to be detected can be continuously stirred by the stirring device 3, so that the sample flow is promoted, and the electrolysis effect is improved. In the detection process, the sample to be detected is continuously stirred by the stirring device 3, so that the sample flow is promoted, and the enrichment of thallium in the sample to be detected on the working electrode 6 is accelerated.

It can be understood that the temperature of the sample to be tested is controlled to be kept stable according to the temperature requirement in the electrolysis process and the three-electrode detection process. Specifically, the working state of the thermostat device is controlled by the control system to meet the high-temperature requirement of the preprocessing stage and the constant-temperature requirement of the three-electrode detection stage, for example, the temperature requirement of the three-electrode detection stage is controlled at 25 ℃, so as to ensure the reliability of the test result.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.