Method for detecting methylene blue in wastewater based on microwave radiation spectrum

Abstract

The invention discloses a method for detecting methylene blue in wastewater based on a microwave radiation spectrum. Mixing Ti2C3 MXene and the graphene oxide dispersion liquid in proportion, adding a calcium chloride solution, and heating in a constant-temperature drying box to obtain calcium ion regulated GO / MXene hydrogel; and cleaning the obtained hydrogel, putting the hydrogel into a solution containing methylene blue, and adsorbing the methylene blue in the solution. After adsorption of the methylene blue is completed, a sample is taken out and treated with a freeze drying method, and the methylene blue-containing GO / MXene aerogel regulated and controlled by calcium ions is obtained; carrying out microwave radiation on the aerogel, and collecting a luminescence spectrum at the same time; spectral results show that the microwave radiation spectrum of the GO / MXene aerogel regulated and controlled by the calcium ions can be changed due to adsorption of methylene blue. The method provided by the invention realizes detection of methylene blue in wastewater, is simple and convenient to operate and high in sensitivity, and is easy to use and popularize on a large scale.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for detecting methylene blue in wastewater based on microwave radiation spectrum. Background Art

[0002] With the rapid development of the industrial economy, water pollution caused by chemically stable organic methylene blue has become an environmental problem that needs to be solved urgently. Materials such as perovskite, manganese ore, graphene oxide and diatomaceous earth can effectively remove methylene blue pollutants from wastewater after appropriate modification. In this context, how to achieve accurate detection of trace methylene blue in water bodies and effectively evaluate the removal efficiency of selected mineral materials for methylene blue pollutants has become a key research focus in this field. Traditional methylene blue detection methods such as chromatography and spectroscopy have disadvantages such as complex operation, high cost and long time consumption. Therefore, it is of great significance to develop a rapid, sensitive and simple method for methylene blue detection.

[0003] Graphene oxide (GO) has shown good application prospects in the field of wastewater treatment due to its unique physical and chemical properties. MXene materials have excellent electrical conductivity and rich surface functional groups, and their performance can be improved by compounding with GO. The introduction of calcium ions can further regulate the adsorption and optical properties of the material. The GO / MXene hydrogel regulated by the introduction of both metal ions shows a characteristic peak of GO at 553.1nm before the adsorption of methylene blue, and a characteristic peak appears at 670.3nm after the adsorption of methylene blue. This peak is the characteristic peak of MXene. Based on this, the present invention can effectively detect methylene blue in wastewater with high sensitivity. Summary of the Invention

[0004] The present invention provides a method for detecting methylene blue in wastewater based on microwave radiation spectroscopy. The calcium ion-regulated GO / MXene hydrogel solves the problems of complex methylene blue detection methods and low sensitivity in the existing technology.

[0005] The technical solutions of the present invention are as follows:

[0006] The present invention provides a method for preparing a calcium ion-regulated GO / MXene hydrogel. MXene and graphene oxide are mixed in proportion, a calcium ion solution is added, and the mixture is heated under high temperature conditions to prepare the calcium ion-regulated GO / MXene hydrogel.

[0007] Furthermore, the MXene material is Ti3C2.

[0008] Furthermore, 300 μL of 1 mol / L calcium ion solution was added.

[0009] Furthermore, the mixture was heated at 100° C. for 15 hours.

[0010] The present invention provides a calcium ion-regulated GO / MXene hydrogel, which is prepared by the above method.

[0011] The present invention also provides a method for detecting methylene blue in wastewater based on microwave radiation spectroscopy, comprising the following steps:

[0012] Step 1: using the hydrogel according to claim 5 to adsorb methylene blue in a solution;

[0013] Step 2: After the static adsorption is completed, take out the sample and perform freeze-drying;

[0014] Step 3: The freeze-dried aerogel is subjected to microwave irradiation, and a spectrometer is used to collect the luminescence spectrum. The presence of methylene blue is determined by the changes in the microwave radiation spectrum.

[0015] Furthermore, the detection wavelength of the luminescence spectrum is 400-800 nm. Compared with the methylene blue before adsorption, the characteristic peak at 553.1 nm in the microwave radiation luminescence spectrum after adsorption becomes weaker or disappears, and the characteristic peak at 670.3 nm appears.

[0016] Furthermore, the adsorption in step 1 is carried out at a temperature below 50°C.

[0017] Beneficial effects

[0018] 1. The prepared hydrogel has good adsorption effect.

[0019] 2. The detection sensitivity is high and trace amounts of dyes can be detected. When the content of methylene blue adsorbed by the hydrogel is only 0.005 g, the method can still show a characteristic peak of 670.3 nm.

[0020] 3. Easy to operate and fast detection speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Spectra of MXene and GO / MXene-CaCl2 composite materials.

[0022] Figure 2 These are spectra of GO / MXene-CaCl2 composite materials with different MXene contents (MXene content is 0%, 20%, 40%, 60%, 80%) without adsorption collection.

[0023] Figure 3 Spectra collected for the adsorption of different contents of methylene blue (MB) on calcium ion modified graphene oxide (GO-CaCl2) with gradients of 3, 1.5, 0.5, and 0.02 mg.

[0024] Figure 4 (a) Schematic diagram of collecting microwave radiation luminescence spectra of composite materials; (b) Spectra collected after GO / MXene-CaCl2 composite materials with different MXene contents adsorbed 3 mg of methylene blue (MXene content of 20%, 40%, 60%, 80%).

[0025] Figure 5 These are the spectra collected after the GO / MXene-CaCl2 composite material with a MXene content of 20% adsorbed different contents of methylene blue (MB content was 0.1, 0.08, 0.06, 0.04, 0.02, 0.01, and 0.005 mg). DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0027] Example

[0028] Step 1: Mix MXene and graphene oxide (GO) dispersions in proportion, add 300ul 1mol / L metal ion solution, and heat at 100 degrees for 15 hours to prepare metal ion-regulated graphene oxide hydrogel.

[0029] Step 2: The hydrogel obtained in step 1 is used to adsorb a certain amount of methylene blue (MB), and the adsorption is carried out at a temperature below 50°C.

[0030] Step 3: After the methylene blue (MB) adsorption is completed, the sample is taken out and freeze-dried.

[0031] Step 4: The aerogel obtained in step 3 is subjected to microwave irradiation, and a spectrometer is used to quickly collect the luminescence spectrum.

[0032] Example 1

[0033] Different from the steps in the above examples, in this example, no MXene was introduced, and only calcium ions were added for modification to prepare calcium ion-modified graphene oxide (GO-CaCl2). The sample was allowed to adsorb MB in a gradient of 3, 1.5, 0.5, and 0.02 mg. The spectrum collected after freeze-drying and microwave irradiation for one minute was as follows: Figure 3 As shown, the results show that the characteristic peak at 670.3 nm does not appear.

[0034] Example 2

[0035] Different from Example 1, this Example 2 introduced MXene according to the steps of the example to prepare two groups of GO / MXene-CaCl2 composite materials with MXene contents of 20%, 40%, 60%, and 80%. One group was used as a control, and the other group adsorbed 3 mg of MB. The spectra collected after freeze-drying and microwave irradiation for one minute are shown as follows: Figure 2 、 Figure 4 As shown in the figure, the results show that even with increased MXene content, the characteristic peak at 670.3 nm cannot be detected in the absence of adsorption. The characteristic peak can only be detected after MB adsorption. Furthermore, a comparison with Example 1 shows that the characteristic peak cannot be detected without the introduction of MXene.

[0036] Example 3

[0037] In Example 3, a GO / MXene-CaCl2 composite material with a MXene content of 20% was prepared according to the steps of the example. 0.1, 0.08, 0.06, 0.04, 0.02, and 0.005 mg of MB were adsorbed on the composite material, and then freeze-dried and microwave irradiated for one minute. The spectra collected are as follows: Figure 5 The results show that the material can detect MB with a lower limit of 0.005 mg, indicating that the invention has high sensitivity in detecting methylene blue in wastewater.

Claims

1. A method for preparing calcium ion-regulated GO / MXene hydrogel, characterized in that: MXene and graphene oxide are mixed in proportion, a calcium ion solution is added, and the mixture is heated under high temperature conditions to prepare the calcium ion-regulated GO / MXene hydrogel.

2. The method for preparing a calcium ion-regulated GO / MXene hydrogel according to claim 1, wherein: The MXene material is Ti3C2.

3. The method for preparing a calcium ion-regulated GO / MXene hydrogel according to claim 1, wherein: Add 300 μL of 1 mol / L calcium ion solution.

4. The method for preparing a calcium ion-regulated GO / MXene hydrogel according to claim 1, wherein: Heat at 100°C for 15 hours.

5. A calcium ion-regulated GO / MXene hydrogel, characterized in that: Prepared by the method according to any one of claims 1 to 4.

6. A method for detecting methylene blue in wastewater based on microwave radiation spectroscopy, characterized in that: The following steps are involved: Step 1: using the hydrogel according to claim 5 to adsorb methylene blue in a solution; Step 2: After the static adsorption is completed, take out the sample and perform freeze-drying; Step 3: The freeze-dried aerogel is subjected to microwave irradiation, and a spectrometer is used to collect the luminescence spectrum. The presence of methylene blue is determined by the changes in the microwave radiation spectrum.

7. A method for detecting methylene blue in wastewater based on microwave radiation spectroscopy according to claim 6, characterized in that, The detection wavelength of the luminescence spectrum is 400-800 nm. Compared with the methylene blue before adsorption, the characteristic peak at 553.1 nm in the microwave radiation luminescence spectrum after adsorption becomes weaker or disappears, and the characteristic peak at 670.3 nm appears.

8. The method for detecting methylene blue in wastewater based on microwave radiation spectroscopy according to claim 6, wherein: The adsorption in the step 1 is carried out at a temperature below 50°C.

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