阅读说明：本技术 一种碳-泡沫铜材料的制备方法及采用其作为工作电极检测环境水体中甲醛的方法 (Preparation method of carbon-foam copper material and method for detecting formaldehyde in environmental water by using carbon-foam copper material as working electrode ) 是由 王颖 李风亭 翟咏昕 于 2020-04-23 设计创作，主要内容包括：本发明公开了一种碳-泡沫铜材料的制备方法及采用其作为工作电极检测环境水体中甲醛的方法。采用改进hummers方法制备氧化石墨烯浸渍溶液后,将长方形泡沫铜材料浸入其中后烘干并无氧条件下高温加热退火后得到作为高灵敏甲醛传感器的碳-泡沫铜材料,采用该碳-泡沫铜材料作为工作电极、Ag/AgCl作为参比电极、铂丝作为对电极,置于不同浓度甲醛标准溶液中用循环伏安法绘制出甲醛与特征响应电流值一一对应的的线性回归方程,测量预处理后的待测环境水体的特征响应电流值代入所述线性回归方程中,通过计算得到所述水体样品中的甲醛浓度。本发明提供的甲醛传感器电极性能稳定、重现性良好,环境水体中甲醛分析速度快,检测成本低。(The invention discloses a preparation method of a carbon-copper foam material and a method for detecting formaldehyde in an environmental water body by using the carbon-copper foam material as a working electrode. Preparing a graphene oxide impregnation solution by adopting an improved hummers method, immersing a rectangular copper foam material in the graphene oxide impregnation solution, drying the rectangular copper foam material, heating and annealing the rectangular copper foam material at a high temperature under an oxygen-free condition to obtain a carbon-copper foam material serving as a high-sensitivity formaldehyde sensor, placing the carbon-copper foam material serving as a working electrode, Ag/AgCl serving as a reference electrode and a platinum wire serving as a counter electrode in formaldehyde standard solutions with different concentrations, drawing linear regression equations with formaldehyde and characteristic response current values in one-to-one correspondence by using a cyclic voltammetry method, measuring the characteristic response current value of a pretreated environment water body to be detected, substituting the characteristic response current value into the linear regression equations, and calculating to obtain the formaldehyde concentration in the water body sample. The formaldehyde sensor electrode provided by the invention has the advantages of stable performance, good reproducibility, high analysis speed of formaldehyde in environmental water and low detection cost.)

1. A preparation method of a carbon-foam copper material is characterized by comprising the following steps:

s1: 1g of graphite and concentrated H₂SO₄、H₃PO₄The three are placed in a three-mouth beaker and concentrated with H₂SO₄、H₃PO₄The volume ratio of (1) to (9), adding 6g of potassium permanganate in portions, and stirring in an ice water bath for 1 h. The temperature is raised to 50 ℃, and the reaction is carried out for 12 hours under the condition of heat preservation. The resulting product was poured into ice water, an appropriate amount of hydrogen peroxide was added until the solution turned golden yellow, filtered, and the product was washed to a pH of approximately 7. Preparing a graphene oxide solution by adopting an improved hummers method, and storing the graphene oxide solution at room temperature in a dark place for later use after the preparation is finished;

s2: cutting the foamy copper material into strips with the thickness of (1-3 cm) × (10-15 cm), performing ultrasonic treatment on the surfaces by adopting an organic solvent and ultrapure water, soaking the strips into the graphene oxide solution obtained in the step S1, soaking the strips for 1-10 min, and drying the strips in a 60 ℃ drying oven for 1-5 h to obtain the foamy copper wrapped by the graphene oxide;

s3: and (4) placing the foamed copper coated with the graphene oxide obtained in the step (S2) in a tube furnace, and heating and annealing for 1-5 h at 300 ℃ in a nitrogen atmosphere to obtain the carbon-foamed copper material.

2. The method for preparing a carbon-copper foam material according to claim 1, wherein the cut strip area of the copper foam in the step S2 is 1cm x 10 cm.

3. The method for detecting formaldehyde in the environmental water body by using the carbon-foam copper material as the working electrode as the claim 1 is characterized by comprising the following steps:

m1: cutting a carbon-foam copper material into strips with the thickness of (1 cm-5 cm) multiplied by (1 cm-5 cm) as working electrodes, adopting Ag/AgCl as reference electrodes and platinum wire electrodes as counter electrodes, and simultaneously placing the working electrodes and the counter electrodes into NaOH solutions containing formaldehyde with different concentrations, wherein the concentration of NaOH in the NaOH solutions is 0.1mol/L, and preparing formaldehyde standard solutions with different concentrations;

m2: detecting the formaldehyde standard solutions with different concentrations obtained in the M2 step by adopting a cyclic voltammetry method to obtain characteristic response current values of formaldehyde with various concentrations, sequentially recording the characteristic response current values corresponding to the formaldehyde standard solutions with various concentrations under the same test condition, drawing a standard curve, and obtaining a linear regression equation by fitting the curve;

m3: after the environmental water body is pretreated, 5mL of treated environmental water body sample to be detected is taken, a cyclic voltammetry method is adopted to detect the water body sample under the condition the same as that of the cyclic voltammetry method in the step M2, the obtained characteristic response current value is substituted into the linear regression equation obtained in the step M2, and the concentration of formaldehyde in the water body sample is obtained through calculation.

4. The method for detecting formaldehyde in environmental water according to claim 3, wherein the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-6mol/L、2.0×10^-6mol/L、4.0×10^-6mol/L、6.0×10^-6mol/L、8.0×10^-6mol/L and 1.0 × 10^-5mol/L。

5. The method for detecting formaldehyde in environmental water according to claim 3, wherein the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-5mol/L、2.0×10^-5mol/L、4.0×10^-5mol/L、6.0×10^-5mol/L、8.0×10^-5mol/L and 1.0 × 10^-4mol/L。

6. The method for detecting formaldehyde in environmental water according to claim 3, wherein the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-4mol/L、2.0×10^-4mol/L、4.0×10^-4mol/L、6.0×10^-4mol/L、8.0×10^-4mol/L and 1.0 × 10^-3mol/L。

7. The method for detecting formaldehyde in the environmental water body according to claim 3, wherein the test conditions of cyclic voltammetry in the M2 step are a voltage range of-0.2V to 0.85V and a sweep rate of 0.05V/S.

8. The method for detecting formaldehyde in the environmental water body according to claim 3, wherein the environmental water body pretreatment method comprises the steps of taking the environmental water body, filtering the environmental water body by using a filter membrane of 0.35-0.55 μm, taking 50 μ L of filtrate into a centrifuge tube, and carrying out constant volume treatment to 5mL by using 0.1mol/L NaOH solution, wherein the pretreatment is finished and the filtrate is stored for later use.

9. The method according to claim 8, wherein the filter membrane has a pore size of 0.45 μm.

Technical Field

The invention belongs to the technical field of electrochemical analysis and detection, and particularly relates to a preparation method of a carbon-copper foam material and a method for detecting formaldehyde in an environmental water body by using the carbon-copper foam material as a working electrode.

Background

Formaldehyde, also known as forminal, has a relative molecular mass of 30.03, a relative density (in air) of 1.067, a 20 ℃ liquid phase (vs. water) density of 0.815, a melting point of-92 ℃ and a boiling point of-21 ℃. The formaldehyde is easy to dissolve in water, is easy to volatilize at normal temperature, and has higher volatilization speed along with the rise of temperature. An aqueous solution containing 37-40% of formaldehyde and 8% of methanol is called formalin solution and is commonly used as a bactericide and a preservative. The formaldehyde is easy to oxidize and polymerize, the concentrated solution can be automatically polymerized into a three-molecule cyclic polymer after being placed at room temperature for a long time, and the high-purity formaldehyde can be polymerized into paraformaldehyde under the condition of a certain catalyst.

Formaldehyde is the simplest aldehyde molecule, a key platform reagent for many other materials and compounds, and one of the most widely used chemicals in the world. It can be used in resin, adhesive, plastic industry, building material and other fields, and also as industrial disinfectant and antiseptic in medical laboratory, agriculture and food production. In addition, it has also found a viable application in energy related applications such as fuel cells and the electroless plating industry. Therefore, the wastewater discharged in the chemical industry, the pharmaceutical industry and other industries also contains a large amount of formaldehyde. The formaldehyde contained in the wastewater is extremely volatile at normal temperature into colorless gaseous formaldehyde with pungent odor, is a substance with high toxicity, and can directly react with protein in microorganisms to cause the death of the microorganisms or inhibit the biological activity of the microorganisms. Formaldehyde has an irritant effect on the skin and mucous membranes of the human body and is identified as a teratogenic and mutagenic substance by the World Health Organization (WHO) and the United states Environmental Protection Agency (EPA). In the list of carcinogens published by the international agency for research on cancer in the world health organization international, 10 and 27 months in 2017, formaldehyde is on a list of one type of carcinogen. In 2019, 7 and 23, formaldehyde is listed in the list of toxic and harmful water pollutants (first batch).

Disclosure of Invention

The invention aims to provide a preparation method of a carbon-foam copper material which has stable electrode performance and good reproducibility and can be used as a working electrode, and a method for detecting formaldehyde in an environmental water body, which adopts the carbon-foam copper material as the working electrode and has the advantages of high analysis speed and low detection cost.

In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a carbon-foam copper material comprises the following steps:

s1: 1g of graphite and concentrated H₂SO₄、H₃PO₄The three are placed in a three-mouth beaker and concentrated with H₂SO₄、H₃PO₄The volume ratio of (1) to (9), adding 6g of potassium permanganate in portions, and stirring in an ice water bath for 1 h. Temperature ofRaising the temperature to 50 ℃, and keeping the temperature for reaction for 12 hours. The resulting product was poured into ice water, an appropriate amount of hydrogen peroxide was added until the solution turned golden yellow, filtered, and the product was washed to a pH of approximately 7. Preparing a graphene oxide solution by adopting an improved hummers method, and storing the graphene oxide solution at room temperature in a dark place for later use after the preparation is finished;

s2: cutting the foamy copper material into strips with the thickness of (1-3 cm) × (10-15 cm), performing ultrasonic treatment on the surfaces by adopting an organic solvent and ultrapure water, soaking the strips into the graphene oxide solution obtained in the step S1, soaking the strips for 1-10 min, and drying the strips in a 60 ℃ drying oven for 1-5 h to obtain the foamy copper wrapped by the graphene oxide;

s3: and (4) placing the foamed copper coated with the graphene oxide obtained in the step (S2) in a tube furnace, and heating and annealing for 1-5 h at 300 ℃ in a nitrogen atmosphere to obtain the carbon-foamed copper material.

Further, the area of the strip of the cut copper foam in the step S2 is 1cm × 10 cm.

Further, the method comprises the following steps:

m1: cutting a carbon-foam copper material into strips with the thickness of (1 cm-5 cm) multiplied by (1 cm-5 cm) as working electrodes, adopting Ag/AgCl as reference electrodes and platinum wire electrodes as counter electrodes, and simultaneously placing the working electrodes and the counter electrodes into NaOH solutions containing formaldehyde with different concentrations, wherein the concentration of NaOH in the NaOH solutions is 0.1mol/L, and preparing formaldehyde standard solutions with different concentrations;

m2: detecting the formaldehyde standard solutions with different concentrations obtained in the M2 step by adopting a cyclic voltammetry method to obtain characteristic response current values of formaldehyde with various concentrations, sequentially recording the characteristic response current values corresponding to the formaldehyde standard solutions with various concentrations under the same test condition, drawing a standard curve, and obtaining a linear regression equation by fitting the curve;

m3: after the environmental water body is pretreated, 5mL of treated environmental water body sample to be detected is taken, a cyclic voltammetry method is adopted to detect the water body sample under the condition the same as that of the cyclic voltammetry method in the step M2, the obtained characteristic response current value is substituted into the linear regression equation obtained in the step M2, and the concentration of formaldehyde in the water body sample is obtained through calculation.

Further, the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-6mol/L、2.0×10^-6mol/L、4.0×10^-6mol/L、6.0×10^-6mol/L、8.0×10^-6mol/L and 1.0 × 10^-5mol/L。

Further, the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-5mol/L、2.0×10^-5mol/L、4.0×10^-5mol/L、6.0×10^-5mol/L、8.0×10^-5mol/L and 1.0 × 10^-4mol/L。

Further, the concentration of the formaldehyde standard solution with different concentrations in the M1 step is 1.0 × 10^-4mol/L、2.0×10^-4mol/L、4.0×10^-4mol/L、6.0×10^-4mol/L、8.0×10^-4mol/L and 1.0 × 10^-3mol/L。

Further, the test conditions of cyclic voltammetry in the M2 step are a voltage range of-0.2V to 0.85V and a sweep rate of 0.05V/S.

Further, the environmental water body pretreatment method comprises the steps of taking an environmental water body, filtering the environmental water body by using a 0.35-0.55 micron filter membrane, taking 50 mu L of filtrate into a centrifuge tube, and carrying out constant volume treatment to 5mL by using 0.1mol/L NaOH solution, wherein the pretreatment is finished and the filtrate is stored for later use.

Further, the pore size of the filter membrane is 0.45 μm.

Compared with the prior art, the invention has the beneficial effects that:

based on the electrochemical technology, the prepared foam copper loaded with reduced graphene oxide is directly used as a working electrode, the preparation process is simple, the electrode performance is stable, the reproducibility is good, the foam copper loaded with reduced graphene oxide can be used for directly carrying out electrochemical detection on formaldehyde, the analysis speed is high, and the detection cost is low^-6mol/L-1.0×10^-3mol/L, the detection minimum is 1 × 10^-6The mol/L is a novel high-sensitivity high-flux electrochemical sensing method, and provides a novel method for detecting formaldehyde.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 is a cyclic voltammetry curve of a reduced graphene oxide loaded copper foam electrode in the absence of formaldehyde and at a formaldehyde concentration of 0.5 mM.

FIG. 2 is a standard curve of response current of formaldehyde solution with the concentration of 1-10 μm on a reduced graphene oxide loaded foam copper electrode and the corresponding concentration;

FIG. 3 is a standard curve of response current of a formaldehyde solution with a concentration of 10 μm to 0.1mM on a reduced graphene oxide loaded copper foam electrode versus the corresponding concentration;

FIG. 4 is a standard curve of response current of 0.1mM to 1mM formaldehyde solution on a reduced graphene oxide loaded copper foam electrode versus its corresponding concentration.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.