MnO2 / GO@Fe2O3 composite aerogel, a preparation method and application thereof

Abstract

The application discloses MnO2 / GO@Fe2O3 composite aerogel and a preparation method and application thereof. The preparation method of the composite aerogel comprises the following steps: preparing manganese dioxide nanotubes; mixing the manganese dioxide nanotubes with graphene oxide and performing a hydrothermal reaction to obtain manganese dioxide / graphene composite aerogel; immersing the manganese dioxide / graphene composite aerogel in a solution containing iron salt and methyl orange, and obtaining a solid mixture after solid-liquid separation; and calcining the solid mixture to obtain the MnO2 / GO@Fe2O3 composite aerogel. The composite aerogel is simple in preparation process and simple in operation process, can effectively remove arsenic in weak acid wastewater, is easy to separate from the wastewater, can be repeatedly used, and solves the problems that single-component arsenic removal powder materials are prone to agglomeration and difficult to separate.

Description

Technical Field

[0001] This invention belongs to the field of functional composite materials technology, and particularly relates to a MnO2 / GO@Fe2O3 composite aerogel, its preparation method and application. Background Technology

[0002] Arsenic is a ubiquitous and highly toxic nonmetallic element, widely present in surface and groundwater. Besides naturally occurring arsenic, arsenic pollution also originates from industrial production, such as the discharge of acidic mine water and industrial residues, as well as wastewater treatment processes, all of which release toxic As(III) and As(V) into soil, groundwater, and drinking water. Prolonged consumption of arsenic-contaminated water can cause skin diseases, cardiovascular diseases, and even cancer. Therefore, arsenic remediation has become one of the most pressing environmental problems to be solved.

[0003] Common methods for arsenic removal include precipitation, ion exchange, adsorption, and membrane separation, as well as pre-oxidative adsorption using redox reactions and photocatalytic oxidation adsorption. Common adsorbent materials in adsorption methods include various carbon materials, clay materials, rare earth materials, and iron oxides such as magnetite and hematite. Graphene-like materials, with their unique structure and extremely large specific surface area, exhibit performance far superior to traditional adsorbent materials and have been used to load iron oxides with an affinity for arsenic. However, while modified graphene composites can improve arsenic removal efficiency, the modification process involves organic reactions and is complex. Furthermore, the adsorption and removal capacity of iron oxides for As(III) is far less than that for As(V). In addition, most current adsorbent materials are in powder form, which is not conducive to efficient separation after adsorption. Therefore, finding an arsenic removal material that is simple to prepare, has strong adsorption capacity, and can be easily reused is one of the key and challenging research directions. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, the present invention aims to provide a MnO2 / GO@Fe2O3 composite aerogel, its preparation method, and its application, thereby solving the problem that single iron-manganese binary oxide materials have insufficient arsenic removal capacity and are not conducive to recycling.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0007] S1. Preparation of manganese dioxide nanotubes;

[0008] S2. Manganese dioxide nanotubes and graphene oxide are mixed and subjected to a hydrothermal reaction to obtain manganese dioxide / graphene composite aerogel;

[0009] S3. The manganese dioxide / graphene composite aerogel was immersed in a solution containing iron salt and methyl orange, and a solid mixture was obtained after solid-liquid separation;

[0010] S4. Calcine the above solid mixture to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0011] Preferably, in step S2, the mass ratio of manganese dioxide nanotubes to graphene oxide is 1:1-5.

[0012] Preferably, in step S2, the hydrothermal reaction temperature is 160-180℃ and the hydrothermal reaction time is 12-24h.

[0013] Preferably, in step S3, the mass ratio of manganese dioxide / graphene composite aerogel, iron salt and methyl orange is 20-50:3-5:1.

[0014] Preferably, in step S3, the soaking time is 8-12 hours.

[0015] Preferably, in step S3, the iron salt is ferric chloride and / or ferric nitrate.

[0016] Preferably, in step S4, the calcination temperature is 600-650℃ and the calcination time is 8-12h.

[0017] The present invention also provides a MnO2 / GO@Fe2O3 composite aerogel prepared by the above method.

[0018] This invention also provides an application of the MnO2 / GO@Fe2O3 composite aerogel prepared by the above method in the removal of arsenic from wastewater.

[0019] Preferably, the above application includes: adjusting the pH of the wastewater to 2-5, then adding MnO2 / GO@Fe2O3 composite aerogel and stirring or shaking at room temperature.

[0020] The beneficial effects of this invention are:

[0021] This invention utilizes the high specific surface area of ​​manganese dioxide nanotube / graphene composite aerogel, which can effectively adsorb methyl orange. The chelation between methyl orange and iron ions further allows the manganese dioxide nanotube / graphene composite aerogel to adsorb iron ions, ultimately yielding a MnO2 / GO@Fe2O3 composite aerogel with a high iron loading. Furthermore, the effective composite of graphene, iron oxide, and manganese dioxide solves the problem of low arsenic removal efficiency of each individual component in wastewater. The composite aerogel provided by this invention has a simple preparation process and straightforward operation. It not only effectively removes arsenic from weakly acidic wastewater but is also easily separated from wastewater, reusable, and reduces operating costs. It also solves the problems of easy agglomeration and difficulty in separation of single-component arsenic removal powder materials. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] The preparation method of MnO2 / GO@Fe2O3 composite aerogel provided in this embodiment of the invention includes the following steps:

[0024] S1. Preparation of manganese dioxide nanotubes; This invention does not limit the preparation method of manganese dioxide nanotubes, and can be any method that can be used in the field.

[0025] S2. Manganese dioxide nanotubes and graphene oxide are mixed at a mass ratio of 1:1-5, and then hydrothermally reacted at a temperature of 160-180℃ for 12-24h to obtain manganese dioxide / graphene composite aerogel.

[0026] S3. Immerse the manganese dioxide / graphene composite aerogel in a solution containing iron salt and methyl orange. The mass ratio of manganese dioxide / graphene composite aerogel, iron salt and methyl orange is 20-50:3-5:1. The iron salt is preferably ferric chloride and / or ferric nitrate. After immersion for 8-12 hours, separate the solid and liquid to obtain a solid mixture.

[0027] S4. Calcine the solid mixture at a temperature of 600-650℃ for 8-12 hours to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0029] Example 1

[0030] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0031] 1) Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0032] 2) Manganese dioxide nanotubes were added to a graphene oxide solution and hydrothermally reacted to obtain a manganese dioxide / graphene composite aerogel. The mass ratio of manganese dioxide nanotubes to graphene oxide was 1:1. The hydrothermal reaction temperature was 180℃ and the reaction time was 24h.

[0033] 3) Immerse the manganese dioxide / graphene composite aerogel in a solution containing ferric chloride and methyl orange, with a mass ratio of composite aerogel, ferric chloride and methyl orange of 25:3:1, for 10 hours; then remove the black gel and dry it in an oven.

[0034] 4) The dried black gel was heated and calcined at 650℃ for 8 hours to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0035] Example 2

[0036] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0037] 1) Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0038] 2) Manganese dioxide nanotubes were added to a graphene oxide solution and hydrothermally reacted to obtain a manganese dioxide / graphene composite aerogel. The mass ratio of manganese dioxide nanotubes to graphene oxide was 1:3. The hydrothermal reaction temperature was 160℃ and the reaction time was 12h.

[0039] 3) Immerse the manganese dioxide / graphene composite aerogel in a solution containing ferric nitrate and methyl orange, with a mass ratio of composite aerogel, ferric nitrate and methyl orange of 50:5:1, for 12 hours; then remove the black gel and dry it in an oven.

[0040] 4) The dried black gel was heated and calcined at 600℃ for 12h to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0041] Example 3

[0042] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0043] 1) Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0044] 2) Manganese dioxide nanotubes were added to a graphene oxide solution and hydrothermally reacted to obtain a manganese dioxide / graphene composite aerogel. The mass ratio of manganese dioxide nanotubes to graphene oxide was 1:5. The hydrothermal reaction temperature was 170℃ and the reaction time was 18h.

[0045] 3) Immerse the manganese dioxide / graphene composite aerogel in a solution containing ferric chloride and methyl orange, with a mass ratio of composite aerogel, ferric chloride and methyl orange of 30:4:1, and soak for 10 hours; then take out the black gel and dry it in an oven.

[0046] 4) The dried black gel was heated and calcined at 650℃ for 10h to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0047] Example 4

[0048] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0049] 1) Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0050] 2) Manganese dioxide nanotubes were added to a graphene oxide solution and hydrothermally reacted to obtain a manganese dioxide / graphene composite aerogel. The mass ratio of manganese dioxide nanotubes to graphene oxide was 1:4. The hydrothermal reaction temperature was 180℃ and the reaction time was 18h.

[0051] 3) Immerse the manganese dioxide / graphene composite aerogel in a solution containing ferric chloride and methyl orange, with a mass ratio of composite aerogel, ferric chloride and methyl orange of 30:3:1, and soak for 12 hours; then take out the black gel and dry it in an oven.

[0052] 4) The dried black gel was heated and calcined at 650℃ for 10h to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0053] Comparative Example 1

[0054] A method for preparing MnO2 / GO@Fe2O3 composite aerogel includes the following steps:

[0055] 1) Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0056] 2) Manganese dioxide nanotubes were added to a graphene oxide solution and hydrothermally reacted to obtain a manganese dioxide / graphene composite aerogel. The mass ratio of manganese dioxide nanotubes to graphene oxide was 1:1. The hydrothermal reaction temperature was 180℃ and the reaction time was 24h.

[0057] 3) Immerse the manganese dioxide / graphene composite aerogel in ferric chloride solution with a mass ratio of composite aerogel to ferric chloride of 25:3 and an immersion time of 10 hours; then remove the black gel and place it in an oven to dry.

[0058] 4) The dried black gel was heated and calcined at 650℃ for 8 hours to obtain MnO2 / GO@Fe2O3 composite aerogel.

[0059] Comparative Example 2

[0060] Manganese dioxide nanotubes were synthesized according to the literature (Journal of Power Sources 2013, 241, 359-366).

[0061] Comparative Example 3

[0062] Graphene oxide was subjected to a hydrothermal reaction to obtain graphene aerogel. The hydrothermal reaction temperature was 180℃ and the hydrothermal reaction time was 24h.

[0063] Comparative Example 4

[0064] After drying the ferric chloride solution in an oven, it was heated and calcined at 650℃ for 8 hours to obtain the iron oxide material.

[0065] The materials prepared in the above embodiments and comparative examples were tested:

[0066] The pH of an 8 mg / L sodium arsenite solution was adjusted to 2 using 0.1 mol / L hydrochloric acid and 0.1 mol / L sodium hydroxide. Then, 4 mg / mL of aerogel material was added and the solution was shaken at room temperature. After adsorption, the solution was filtered through a 0.22 μm microfiltration membrane, and the arsenic removal rate of the resulting supernatant was determined by ICP. The adsorbed composite aerogel was directly removed from the solution and desorbed using 1 mol / L NaOH as the eluent. This adsorption-desorption process was repeated five times. The test results are listed in Table 1.

[0067] Table 1 Test results for each embodiment and comparative example

[0068]

[0069] As can be seen from the table above, the MnO2 / GO@Fe2O3 composite aerogel prepared in the embodiments of the present invention has a high specific surface area and a good removal effect on arsenic. Moreover, it still has a high arsenic removal efficiency after being recycled five times. The composite aerogel can be directly taken out from the treated wastewater and recycled, which effectively reduces the cost of use.

[0070] Compared with Comparative Example 1, the specific surface area of ​​the composite material in Example 1 was significantly increased, indicating that the chelation between methyl orange and ferric ions can promote the adsorption of iron ions by manganese dioxide nanotube / graphene composite aerogel, thereby obtaining MnO2 / GO@Fe2O3 composite aerogel with higher iron content and improving the removal effect of arsenic.

[0071] Compared with Comparative Examples 2, 3 and 4, Example 1 shows that the present invention solves the problem of low removal efficiency of arsenic in wastewater by graphene, manganese dioxide and iron oxide by the effective combination of graphene, iron oxide and manganese dioxide.

[0072] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0073] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing MnO2 / GO@Fe2O3 composite aerogel, characterized in that, Includes the following steps: S1. Preparation of manganese dioxide nanotubes; S2. Manganese dioxide nanotubes and graphene oxide are mixed and subjected to a hydrothermal reaction to obtain manganese dioxide / graphene composite aerogel; S3. The manganese dioxide / graphene composite aerogel was immersed in a solution containing iron salt and methyl orange, and a solid mixture was obtained after solid-liquid separation; S4. Calcine the solid mixture to obtain MnO2 / GO@Fe2O3 composite aerogel.

2. The method for preparing MnO2 / GO@Fe2O3 composite aerogel according to claim 1, characterized in that, In step S2, the mass ratio of manganese dioxide nanotubes to graphene oxide is 1:1-5.

3. In the preparation method of MnO2 / GO@Fe2O3 composite aerogel according to claim 1, in step S2, the hydrothermal reaction temperature is 160-180℃ and the hydrothermal reaction time is 12-24h.

4. The method for preparing MnO2 / GO@Fe2O3 composite aerogel according to claim 1, characterized in that, In step S3, the mass ratio of the manganese dioxide / graphene composite aerogel, iron salt, and methyl orange is 20-50:3-5:

1.

5. The method for preparing MnO2 / GO@Fe2O3 composite aerogel according to claim 1, characterized in that, In step S3, the soaking time is 8-12 hours.

6. The method for preparing MnO2 / GO@Fe2O3 composite aerogel according to claim 1, characterized in that, In step S3, the iron salt is ferric chloride or ferric nitrate.

7. The method for preparing MnO2 / GO@Fe2O3 composite aerogel according to claim 1, characterized in that, In step S4, the calcination temperature is 600-650℃ and the calcination time is 8-12h.

8. The MnO2 / GO@Fe2O3 composite aerogel prepared by the method according to any one of claims 1 to 7.

9. The application of the MnO2 / GO@Fe2O3 composite aerogel prepared by the method according to any one of claims 1 to 7 in the removal of arsenic from wastewater.

10. The application according to claim 9, characterized in that, include: The pH of the wastewater was adjusted to 2-5, and then the MnO2 / GO@Fe2O3 composite aerogel was added and stirred or shaken at room temperature.

Images