A Tl + Testing materials, Tl + Detection electrode and its preparation method

Abstract

This invention discloses a Tl + Testing materials, Tl + Detection electrode and its preparation method, the Tl + The test material is Ti3C2T x The material contains composite TiO2; its preparation method includes step 1, preparing Ti3C2T x Step 2: Preparation of TiO2 / Ti3C2T x Composite materials. Tl + The detection electrode is made of TiO2 / Ti3C2T x Composite material modified glassy carbon electrode; its preparation method is as follows: using TiO2 / Ti3C2T x The preparation method of the glassy carbon electrode modified with composite materials is as follows: polishing, cleaning, and drying the glassy carbon electrode; then, applying TiO2 / Ti3C2T... x The dispersion was uniformly dropped onto the surface of a glassy carbon electrode, and then dried to evaporate the tetrahydrofuran. The technical advantages of this invention are: [The invention's Tl...] + The detection electrode is used to detect thallium ions and exhibits good stability and linearity, with a detection limit of 0.2 pmol / L in the high concentration range.

Description

Technical Field

[0001] This invention belongs to the field of ion analysis and detection technology, specifically relating to the detection of monovalent thallium ions. Background Technology

[0002] Thallium is a typical toxic metallic element, more toxic to living organisms than heavy metals such as lead, zinc, and mercury. It exists in two oxidation states, +1 and +3, and is mainly found in nature as Tl. + The state exists, Tl + It is chemically stable and highly mobile, making it suitable for detecting Tl in the environment. + This presents certain challenges. Thallium pollution mainly originates from mineral mining and industrial production. Improper handling of its solid and liquid waste can lead to serious environmental pollution problems. Therefore, rapid detection of Tl+ is of great significance for environmental monitoring.

[0003] Currently, commonly used methods for determining thallium ions in solution include differential pulse anodic stripping voltammetry (DPASV), square wave anodic stripping voltammetry (SWASV), emission spectroscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), graphite furnace atomic absorption spectrometry (GFAAS), and spectrophotometry. Although these methods are simple to operate, they require expensive instruments, and the low concentration of thallium in water can introduce errors, affecting the accuracy of the results. Therefore, a low-cost, simple, miniaturized, and accurate method for determining thallium ions in solution is needed. + There is a strong demand for detection and analysis technologies. Summary of the Invention

[0004] To address the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a Tl + The detection material can be used to detect monovalent thallium ions. A Tl is also provided. + The detection electrode exhibits a stable linear relationship between its electrical properties and the Tl+ concentration. A Tl+ detection electrode is also provided. + Testing materials and Tl + Method for preparing the detection electrode.

[0005] To solve the above technical problems, the following technical solution is adopted:

[0006] The present invention provides a Tl + The test material is in Ti3C2T x TiO2 is incorporated into the material.

[0007] The present invention provides a Tl + The method for preparing the detection material includes the following steps:

[0008] Step 1: Preparation of Ti3C2T x

[0009] Ti3AlC2 powder was mixed with lithium fluoride and hydrochloric acid aqueous solution and stirred. The mixture was then washed with deionized water by centrifugation until the pH of the supernatant reached 5. The precipitate was redispersed with deionized water, vigorously shaken to separate into layers, and collected after centrifugation to obtain Ti3C2T. x Colloidal solutions;

[0010] Step 2: Preparation of TiO2 / Ti3C2T x Composite materials

[0011] Ti3C2T x After dilution of the colloidal solution, it was vacuum filtered on a PVDF substrate, and then the TiO2 powder was ultrasonically treated with anhydrous ethanol. Subsequently, the dispersed TiO2 solution was slowly added dropwise to Ti3C2T x Vacuum filtration was continued on the membrane, and finally, the TiO2 and Ti3C2T on the PVDF substrate were freeze-dried. x The composite material was peeled off to obtain TiO2 / Ti3C2T x Composite materials.

[0012] The present invention provides a Tl+ detection electrode made of TiO2 / Ti3C2T x Glassy carbon electrode modified with composite materials.

[0013] The present invention provides a Tl + The detection electrode was prepared as follows: the glassy carbon electrode was polished with alumina, then ultrasonically cleaned with acetone and anhydrous ethanol sequentially. It was then rinsed with distilled water and dried; the TiO2 / Ti3C2T electrode was then... x After ultrasonically dispersing the composite powder with tetrahydrofuran, it was uniformly dropped onto the surface of a glassy carbon electrode and then dried to evaporate the tetrahydrofuran.

[0014] The technical effects of this invention are:

[0015] The present invention Tl + The detection electrode is used to detect thallium ions and has good stability and detection capability. + Within the concentration range of 1–100,000 pmol / L, the linear relationship is Y(μA) = 2.02lg[C]. Tl+ The linear relationship was +19.13, indicating a good linearity. The detection limit within this concentration range was 0.2 pmol / L. Attached Figure Description

[0016] The accompanying drawings of this invention are described below:

[0017] Figure 1 TiO2 / Ti3C2T x and Ti3C2T xXRD patterns;

[0018] Figure 2 Impedance spectra of the three electrodes;

[0019] Figure 3 For different Tl + DPV curves at different concentrations;

[0020] Figure 4 For different Tl + lg[C] at concentration Tl+ Linear relationship between the peak current and oxidation current. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0022] Example

[0023] I. Tl + The preparation method of the detection material includes the following steps:

[0024] Step 1: Preparation of Ti3C2T x

[0025] 1.0 g of Ti3AlC2 powder was mixed with 1.6 g of lithium fluoride and 20 mL of 9 mol / L hydrochloric acid aqueous solution and stirred at 40 °C for 24 h. Subsequently, the mixture was washed multiple times with deionized water at 3500 r / min until the pH of the supernatant reached 5. The precipitate after centrifugation was redispersed with deionized water, vigorously shaken to separate the layers, and then collected after centrifugation to obtain Ti3C2T. x Colloidal solution.

[0026] Step 2: Preparation of TiO2 / Ti3C2T x Composite materials

[0027] The above Ti3C2T x The colloidal solution was diluted with distilled water to 0.01 g / L and then vacuum filtered on a 0.45 μm polyvinylidene fluoride (PVDF) membrane substrate. Then, 1.0 g of purchased TiO2 powder with a particle size of 20-50 nm was ultrasonically treated with anhydrous ethanol for 30 min. Subsequently, the dispersed TiO2 solution was slowly added dropwise to Ti3C2T x Vacuum filtration was continued on the membrane, and finally, the TiO2 and Ti3C2T on the PVDF substrate were removed by freeze drying. x The composite material was peeled off to obtain Ti3C2T x Composite TiO2 materials (abbreviated as TiO2 / Ti3C2T) x ).

[0028] Ti3C2T xand TiO2 / Ti3C2T x The phase structure of the freeze-dried powder was analyzed, and its XRD pattern is shown below. Figure 1 As shown: Figure 1 Ti3C2T x The text indicates that TiC and Ti3C2T are used in this context. x The characteristic peaks were significantly weakened after binding with TiO2, and furthermore, in TiO2 / Ti3C2T x Characteristic diffraction peaks of TiO2 were observed at 2θ of 25.3° and 37.8° in the composite material spectrum, corresponding to crystal planes (101) and (004), respectively, and the surface Ti3C2T x TiO2 has been successfully loaded onto the surface.

[0029] 2. Tl + Method for preparing the detection electrode,

[0030] The glassy carbon electrode was polished with alumina, then ultrasonically cleaned with acetone and anhydrous ethanol for 10 minutes each, rinsed three times with distilled water, and dried for later use. The above TiO2 / Ti3C2T... x After ultrasonically dispersing the composite powder with tetrahydrofuran for 30 minutes, it was uniformly dropped onto the surface of a glassy carbon electrode using a micropipette. After drying and evaporating the tetrahydrofuran, TiO2 / Ti3C2T was obtained. x Modified glassy carbon electrode.

[0031] Preparation of the contrast electrode:

[0032] TiO2 / Ti3C2T x The composite powder was replaced with Ti3C2T x Powder, the process of which is related to TiO2 / Ti3C2T x The modified glassy carbon electrode was prepared in the same manner, yielding Ti3C2T x Modified glassy carbon electrode.

[0033] Using the same steps, without adding anything, an unmodified glassy carbon electrode was prepared.

[0034] III. Electrochemical Performance Testing

[0035] Unmodified glassy carbon electrode, Ti3C2T x Modified glassy carbon electrode and TiO2 / Ti3C2T x The three types of modified glassy carbon electrodes were immersed in 0.01 mol / L TlNO3 solution for 12 h to ensure that the electrodes were saturated with thallium ions and to avoid the effects of adsorption and complexation.

[0036] The three electrodes after soaking were subjected to electrochemical impedance spectroscopy (EIS) on an electrochemical workstation CHI 660, and the resulting spectra are shown below. Figure 2 As shown, the electrode resistance is represented by the radius of the high-frequency region of the curve. Figure 2 In the diagram, the vertical axis Z″ represents the imaginary impedance, with the unit of impedance being Ohm, and Z' represents the real impedance. Figure 2 It can be seen that among the three types of electrodes, the glassy carbon electrode has the smallest curve radius in the electrochemical impedance spectroscopy curves, as shown by Ti3C2T. x The modified curve has the largest radius and the largest resistance. (TiO2 / Ti3C2T) x The smaller radius of the curve for the modified glassy carbon is due to the Ti3C2T material. x The TiO2 on the surface provides more electrochemical active sites, shortens the ion transport channel, promotes electron transfer, and also indicates that TiO2 / Ti3C2T x The material was successfully modified onto the surface of a glassy carbon electrode, TiO2 / Ti3C2T x Modified glassy carbon electrode is better than Ti3C2T x The modified electrode exhibits better stability.

[0037] IV. TiO2 / Ti3C2T x Modified glassy carbon electrode for Tl + Detection range

[0038] Differential pulse voltammetry (DPV) was used to test and record different Tl values. + The current change curve at different concentrations, and the test results are as follows: Figure 3 As shown, from Figure 3 It can be clearly seen from the Tl + As concentration increases, Tl + The oxidation peak current also increases. The oxidation peak current is related to Tl. + The concentration shows a clear linear relationship, such as Figure 4 As shown, at low Tl + Within the concentration range of 0.001–0.1 pmol / L, the linear relationship is Y(μA) = 3.91lg[C]. Tl+ +21.85, where R = 0.993, C Tl+ The concentration of Tl+ is expressed in pmol / L. In high Tl... + Within the concentration range of 1–100,000 pmol / L, the linear relationship is Y(μA) = 2.02lg[C]. Tl+ The value was +19.13, with R = 0.997, indicating a good linear relationship between TiO2 / Ti3C2T. x Glassy carbon electrode modified with composite material for Tl + Good detection performance. At high Tl +The detection limit is 0.2 pmol / L within the concentration range (1–100,000 pmol / L).

[0039] V. TiO2 / Ti3C2T x Modified glassy carbon electrode for Tl + Stability test of the test

[0040] TiO2 / Ti3C2T x The glassy carbon electrode modified with composite material was used to continuously measure 100 pmol / L thallium nitrate solution five times. The measured currents are shown in the table below:

[0041] frequency Current (μA) 1 23.19 2 22.89 3 22.94 4 23.30 5 23.10

[0042] The calculated relative standard deviation is 2.33%, indicating that the TiO2 / Ti3C2T of the present invention... x Composite material modified glassy carbon electrode for detecting Tl + It exhibits good stability over time.

Claims

1. A method using TiO2 / Ti3C2T x Composite material testing Tl + The method is characterized by: Step 1, Ti3C2T x Composite TiO2 in materials: Preparation of Ti3C2T x Ti3AlC2 powder was mixed with lithium fluoride and hydrochloric acid aqueous solution and stirred. The mixture was then washed with deionized water by centrifugation until the pH of the supernatant reached 5. The precipitate was redispersed with deionized water, vigorously shaken to separate into layers, and then collected after centrifugation to obtain Ti3C2T. x Colloidal solutions; Preparation of TiO2 / Ti3C2T x Composite materials: Ti3C2T x After dilution of the colloidal solution, it was vacuum filtered on a PVDF substrate, and then the TiO2 powder was ultrasonically treated with anhydrous ethanol. Subsequently, the dispersed TiO2 solution was slowly added dropwise to Ti3C2T x Vacuum filtration continued on the membrane, and finally, the TiO2 and Ti3C2T on the PVDF substrate were freeze-dried. x The composite material was peeled off to obtain TiO2 / Ti3C2T x Composite materials; Step 2, TiO2 / Ti3C2T prepared in step 1 x Composite modified glassy carbon electrode: The glassy carbon electrode was polished with alumina, then ultrasonically cleaned with acetone and anhydrous ethanol in sequence; it was then rinsed with distilled water and dried; the TiO2 / Ti3C2T electrode was then... x After ultrasonically dispersing the composite powder with tetrahydrofuran, it was uniformly dropped onto the surface of a glassy carbon electrode and then dried to evaporate the tetrahydrofuran. Step 3: Using the TiO2 / Ti3C2T prepared in step 2 x Detection of Tl using composite material modified glassy carbon electrode + ion.

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