CeOx quantum dot-iron ore composite material as well as preparation method and application thereof

Abstract

The invention relates to a CeOx quantum dot-iron ore composite material and a preparation method and application thereof, and relates to the technical field of wastewater treatment, and the CeOx quantum dot-iron ore composite material comprises cheap natural siderite as a matrix and CeOx quantum dots loaded on the matrix through a precipitation-roasting method. According to the invention, the CeOx quantum dots are strong in dispersity and good in stability; the composite material has variable valence Ce (IV) / Ce (III) species, so that oxidation detoxification of Fe (III) on Sb (III) is realized; compared with pure siderite, the composite material has a larger effective contact area and more oxidation adsorption points, and the oxidation adsorption effect of siderite on Sb (III) is greatly improved. In conclusion, the composite material disclosed by the invention not only can effectively oxidize and detoxify Sb (III), but also can thoroughly and completely remove Sb (III) from water, so that the aim of thoroughly treating antimony-containing wastewater by using cheap minerals is fulfilled, and the composite material has the advantages of low cost, high efficiency and the like, thereby having a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and specifically relates to a CeO x Quantum dot-iron ore composite material, preparation method and application thereof. Background Art

[0002] Antimony (Sb) is an important chemical raw material, primarily used in flame retardants, batteries, and alloys. Its widespread use in industrial processes has led to a general increase in antimony levels in the environment. Antimony in water, in particular, is easily transported into various water bodies via surface runoff, posing a serious threat to human health. It has been reported that sufficient antimony accumulation in the human body can cause cardiovascular, liver, and respiratory diseases, and Sb(III) is significantly more toxic than Sb(V). Concerned about water safety, the World Health Organization (WHO) has designated antimony as a priority pollutant, establishing a maximum residual concentration of 20 μg / L in drinking water. The European Union, the United States, and Australia limit the maximum concentration of Sb in drinking water to 10 μg / L, 6 μg / L, and 3 μg / L, respectively. my country's current "Standard for Drinking Water Quality" (GB5749-2022), "Surface Water Environmental Quality Standard" (GB3838-2002), and "Groundwater Quality Standard" (GB / T14848-2017) all set an antimony limit of 5 μg / L. Therefore, developing new technologies to oxidize Sb(III) in water to Sb(V) and recover it is essential. Adsorption is a promising method for antimony removal, offering advantages such as high efficiency, low cost, and minimal secondary environmental pollution. There is an urgent need to develop a simultaneous adsorption-oxidation antimony removal technology that can convert the highly toxic Sb(III) into the less toxic Sb(V) and remove it from water.

[0003] Cerium oxide (CeO x ) is a common rare earth oxide, commonly used as polishing materials, catalysts, UV absorbers, fuel cell electrolytes and electronic ceramics. x There are two valence states (Ce 3+ and Ce 4+ ) exists, the unique 4f electronic structure of Ce can promote the transfer of electrons between the two valence states, thus leading to Ce 3+ and Ce 4+ In CeO x Flexible conversion in Ce 3+ / Ce 4+ The coupled electron pairs make CeO x It has good redox ability and oxygen storage / release capacity, and can promote the redox reactions of some elements and substances (such as Fe, Ni, CO, etc.).

[0004] Siderite is one of the most common iron minerals in nature and is widely distributed in the environment. Siderite has a high specific surface area, sufficient adsorption sites and a positive surface charge at neutral pH, so it has been widely studied for the removal of pollutants from aqueous solutions. The main component of natural siderite is FeCO3, which has a good reducing effect. Pure FeCO3 cannot oxidize Sb(III). By roasting siderite, part of Fe 2+ Converted to Fe 3+ Theoretically, Sb(III) oxidation can be achieved, but Fe 3+ The oxidation of Sb(III) is also difficult to occur in practice. Therefore, there are limitations in the application of natural siderite for the removal of Sb(III) from water. It is necessary to treat natural siderite to improve its oxidation performance so that it can be well used for the removal of antimony from water. Summary of the Invention

[0005] The purpose of the present invention is to provide a CeO x Quantum dot-iron ore composite material and its preparation method and application, CeO x With iron ore, that is, with natural siderite composite, through CeO x Modification of natural siderite can induce and accelerate its oxidation process of Sb(III).

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] As a first aspect of the present invention, there is provided a CeO x Quantum dot-iron ore composite material, the composite material comprising a siderite matrix and CeO loaded on the siderite matrix x Quantum dots.

[0008] As a further optimized solution, the CeO x In quantum dot-iron ore composites, CeO x The content is 1%-40%.

[0009] As a second aspect of the present invention, there is provided a CeO x The preparation method of the quantum dot-iron ore composite material comprises the following steps:

[0010] (1) Grinding natural siderite into powder, sieving and setting aside;

[0011] (2) Add cetyltrimethylammonium bromide (CTAB) to the cerium nitrate hexahydrate solution and mix ultrasonically for 30-60 minutes to allow the cerium ions to fully coordinate with the amino groups to ensure that CeO x quantum dot formation;

[0012] (3) adding natural siderite powder, stirring evenly and ultrasonically treating, and then adding NH3·H2O dropwise under stirring to adjust the pH to 10, and obtaining the product after the reaction is completed;

[0013] (4) Filter the product and wash it until there are no ions attached to the surface of the product. After drying the product, calcination is performed to obtain the CeO x Quantum dot-iron ore composites.

[0014] As a further optimized solution, in step (3), the calcination treatment is specifically as follows: heating the product to 350-550°C at a heating rate of 3-10°C / min and keeping the temperature for 2-5h.

[0015] As a third aspect of the present invention, there is also provided a CeO x Application of quantum dot-iron ore composite materials in treating Sb(III)-containing wastewater.

[0016] As a fourth aspect of the present invention, there is also provided a Sb(III) removal adsorbent, comprising any of the CeO x Quantum dot-iron ore composites.

[0017] As a fifth aspect of the present invention, a method for removing Sb(III) from wastewater is also provided, which comprises: adding any of the CeO x The quantum dot-iron ore composite material or the above-mentioned Sb(III) removal adsorbent is put into the Sb(III)-containing wastewater for use. 4+ / Ce 3+ and Fe 2+ / Fe 3+ Under the joint action of electron pairs, the oxidative adsorption of Sb(III) is achieved.

[0018] As a further optimized solution, the CeO x The effective concentration of the quantum dot-iron ore composite material or the Sb(III) removal adsorbent in wastewater is 0.5 g / L-5.0 g / L.

[0019] As a further optimized solution, the pH value of the wastewater is 3-9.

[0020] The beneficial effects of the present invention are:

[0021] (1) CeO x The quantum dot-iron ore composite material includes a siderite matrix and CeO loaded on the siderite matrix. x Quantum dots, CeO xThe quantum dots have strong dispersion and good stability. Compared with pure siderite, the composite material has a larger effective contact area and more oxidation adsorption sites, which greatly improves the oxidation adsorption effect of siderite on Sb(III).

[0022] (2) CeO x Quantum dot-iron ore composites in Ce 4+ / Ce 3+ and Fe 2+ / Fe 3+ Under the joint action of electron pairs, the in situ oxidation of Sb(III) is promoted, which can effectively remove Sb(III) from water and complete the detoxification and recovery of Sb(III), which has broad application prospects.

[0023] (3) CeO x The preparation process of quantum dot-iron ore composite materials is convenient, the synthesis conditions are easy to control, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The 20% CeO in Example 1 provided by the present invention x - Transmission electron microscopy images of iron ore composite materials;

[0025] Figure 2 The 20% CeO in Example 1 provided by the present invention x -Isothermal adsorption-desorption curves of the iron ore composite material and comparative examples 1-4;

[0026] Figure 3 The 20% CeO in Example 1 provided by the present invention x - XRD patterns of the iron ore composite material and comparative examples 1-4;

[0027] Figure 4 The 20% CeO in Example 1 provided by the present invention x - Single element XPS spectrum of iron ore composite materials;

[0028] Figure 5 The test results of using the materials obtained in Example 1 and Comparative Examples 1-8 as adsorbents for removing Sb(III) from water provided by the present invention are as follows;

[0029] Figure 6 The test results of the Sb(III) removal test for water bodies with different pH values ​​provided by the present invention;

[0030] Figure 7 The test results of the present invention for the removal of Sb(III) from water using different adsorbent dosages;

[0031] Figure 8The test results of the Sb(III) removal experiment for different types of natural water bodies provided by the present invention;

[0032] Figure 9 The test results of the present invention for the removal of Sb(III) in the presence of different anions and cations in water;

[0033] Note: Figures 5 to 9 In this case, the pollutants are Sb(III), C t / C0 refers to the ratio of the pollutant concentration at time t to the initial pollutant concentration. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above application content.

[0035] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art. If no specific conditions are specified, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the materials or instruments is not specified, they are all commercially available products.

[0036] Example 1

[0037] The 20% CeO provided in this embodiment x -A method for preparing an iron ore composite material, comprising the following steps:

[0038] (1) Grind the natural siderite, pass it through a 200-mesh sieve, and set aside;

[0039] (2) Prepare 200 mL of 12.6115 g / L cerium nitrate hexahydrate solution, add 5 g of natural siderite powder, stir evenly, and then ultrasonicate for 30 min. Then, add NH3·H2O dropwise at a stirring speed of 250 r / min until the pH reaches 10. After reacting for 240 min, the product is obtained.

[0040] (3) The product was filtered and washed several times with a mixed solution of 50% ethanol and water until there were no ions attached to the surface of the product. The product was dried and placed in a tube furnace and heated to 400°C at a heating rate of 10°C / min for 4 hours to obtain 20% CeO x -Iron ore composite materials.

[0041] Example 2

[0042] The difference from Example 1 is that in step (3), the product is filtered and washed several times with a mixed solution of ethanol and water with an ethanol volume content of 50% until there are no ions attached to the surface of the product. After the product is dried, it is placed in a tube furnace and heated to 350°C at a heating rate of 3°C / min. The holding time is 5 hours to obtain a 20% CeOx-iron ore composite material.

[0043] Example 3

[0044] The difference from Example 1 is that in step (3), the product is filtered and washed several times with a mixed solution of ethanol and water with an ethanol volume content of 50% until no ions are attached to the surface of the product. After the product is dried, it is placed in a tube furnace and heated to 550°C at a heating rate of 3°C / min and kept at this temperature for 2 h to obtain a 20% CeOx-iron ore composite material.

[0045] Comparative Example 1

[0046] The difference from Example 1 is that in step (2), the concentration of the cerium nitrate hexahydrate solution is prepared to be 0 mg / L (i.e., 5 g of natural siderite powder is directly added to ultrapure water), and 0% CeO is prepared. x -Iron ore composite materials.

[0047] Comparative Example 2

[0048] The only difference from Example 1 is that in step (2), the concentration of the cerium nitrate hexahydrate solution is 0.6306 g / L, and 1% CeO is prepared. x -Iron ore composite materials.

[0049] Comparative Example 3

[0050] The only difference from Example 1 is that in step (2), the concentration of the cerium nitrate hexahydrate solution is 3.1529 g / L, and 5% CeO is prepared. x -Iron ore composite materials.

[0051] Comparative Example 4

[0052] The only difference from Example 1 is that in step (2), the concentration of the cerium nitrate hexahydrate solution is 6.3057 g / L, and 10% CeO is prepared. x -Iron ore composite materials.

[0053] Comparative Example 5

[0054] The only difference from Example 1 is that in step (2), the concentration of the cerium nitrate hexahydrate solution is 25.2230 g / L, and 40% CeO is prepared. x -Iron ore composite materials.

[0055] Comparative Example 6

[0056] The only difference from Example 1 is that in step (2), no natural siderite powder is added to prepare pure CeO x Material.

[0057] Comparative Example 7

[0058] According to the mass percentage, 80% of the 0% CeO prepared in Comparative Example 1 was added. x - Iron ore composite material with 20% pure CeO obtained in Comparative Example 6 x The materials are mixed evenly to obtain a mixed adsorbent.

[0059] In addition, natural siderite was crushed and ground, and the natural siderite powder obtained by passing through a 200-mesh sieve was used as Comparative Example 8.

[0060] 1. Structural characterization

[0061] The 20% CeO prepared in Example 1 was observed using a transmission electron microscope. x -80% iron ore composite material was characterized. Figure 1 As shown in the figure, it can be seen that there is CeO on the surface of siderite x Quantum dots are generated, and the particle size of cerium oxide is calculated to be 3-6 nm.

[0062] The 20% CeO prepared in Example 1 x -80% iron ore composite materials and comparative examples 1-4 were subjected to BET characterization. The results are as follows Figure 2 As shown, it can be clearly seen that with the increase of CeO x With the increase of loading amount, the adsorption capacity of the composite material also gradually increases.

[0063] The 20% CeO prepared in Example 1 x - Iron ore composite materials and comparative examples 1-4 were subjected to X-ray diffraction. X-ray diffraction was used to analyze the crystal structure. The results are shown in Figure 2. Figure 3 As shown, the diffraction peak at 2θ = 28.554° corresponds to CeO x The (111) crystal plane of the crystal, and with the CeO x As the loading amount increases, the characteristic peak becomes larger.

[0064] The 20% CeO prepared in Example 1 x - Iron ore composite materials were subjected to X-ray photoelectron spectroscopy analysis. The results are as follows Figure 4 As shown, it can be seen that 20% CeO x -Ce in iron ore composites 3+ and Ce 4+ Coexistence, Fe 2+ and Fe 3+ Coexistence, adsorbed oxygen and lattice oxygen coexist.

[0065] 2. Specific applications

[0066] (1) Water Sb(III) removal test

[0067] The materials obtained in Example 1 and Comparative Examples 1-8 were used as adsorbents to treat Sb(III) in water. The specific method was as follows: several groups of test water bodies containing Sb(III) were prepared (the initial concentration of Sb(III) in the test water bodies was 12 mg / L, using potassium antimony tartrate and laboratory ultrapure water), the pH was adjusted to 7, and then a certain amount of the adsorbent prepared in Example 1 and Comparative Examples 1-8 was added to adjust the concentration of the adsorbent to 1 g / L. The reaction was carried out at room temperature and pressure for 1 hour, and the treatment effect of different adsorbents on Sb(III) in the test water bodies was tested. The test results are shown in FIG. Figure 5 shown.

[0068] Depend on Figure 5 It can be seen that compared with the loaded CeO x Siderite, the use of natural siderite powder can not effectively remove Sb (III) in water, with the CeO x The larger the loading amount, the better the adsorption effect of the adsorbent on Sb(III). x The loading amount of CeO increased from 20% to 40%, but the performance did not improve significantly, indicating that 20% is CeO x The optimal loading amount can effectively remove Sb(III) (removal rate is 95.38%) without wasting the chemical cerium nitrate hexahydrate, thus saving costs. In addition, the removal rate of Sb(III) by the mixed adsorbent prepared in Comparative Example 7 is lower than that of the 20% CeO prepared in Example 1. x - Iron ore composite material, it can be seen that CeO x Simply mixing with siderite does not adsorb Sb(III) well.

[0069] (2) Experiments on Sb(III) removal in water with different pH values

[0070] Several groups of test water bodies containing Sb(III) were prepared (the initial concentration of Sb(III) in the test water bodies was 12 mg / L, prepared using potassium antimony tartrate and laboratory ultrapure water), and the pH was adjusted to 3, 5, 7, and 9, respectively. The material obtained in Example 1 was used as an adsorbent and added to the test water bodies containing Sb(III) at different pH values, and the concentration of the adsorbent was 1 g / L. The reaction was carried out at room temperature and pressure for 1 hour, and the treatment effect of different adsorbents on Sb(III) in the test water bodies was tested. The test results are shown in FIG. Figure 6 shown.

[0071] Depend on Figure 6It can be seen that under acidic conditions, 20% CeO x -The effect of iron ore adsorbent in removing Sb(III) from water is worse than that under neutral and alkaline conditions. The reason is speculated to be that the main component of siderite is FeCO3, which is not completely converted into Fe2O3 even after high-temperature roasting. Furthermore, the decomposition of FeCO3 under acidic conditions affects the structure of the adsorbent, resulting in poor adsorption effect.

[0072] (3) Experiment on Sb(III) removal from water with different adsorbent dosages

[0073] Several groups of test water bodies containing Sb(III) were prepared (the initial concentration of Sb(III) in the test water bodies was 12 mg / L, prepared using potassium antimony tartrate and laboratory ultrapure water) and the pH was adjusted to 7. A certain amount of the material obtained in Example 1 was added to each group of test water bodies as an adsorbent, and the concentrations of the adsorbent were 0.5, 0.8, 1.0, 1.5, and 5.0 g / L, respectively. The reaction was carried out at room temperature and pressure for 1 hour, and the treatment effects of different adsorbents on Sb(III) in the test water bodies were tested. The test results are shown in FIG. Figure 7 shown.

[0074] Depend on Figure 7 It can be seen that under the condition of excess adsorbent, Sb(III) can be completely removed within 60 min, while when the amount of adsorbent is insufficient, the adsorption amount of Sb(III) is reduced accordingly.

[0075] (4) Experiments on Sb(III) removal from different types of natural water bodies

[0076] When preparing the test water, well water, water near the antimony mine, Kuihu Lake water and Yangtze River water were used to prepare the test water containing Sb (III) (the initial concentration of Sb (III) in the test water was 12 mg / L), the pH was adjusted to 7, and then a certain amount of the material obtained in Example 1 was added as an adsorbent, and the concentration of the adsorbent was 1 g / L. The reaction was carried out at room temperature and pressure for 1 hour, and the treatment effect of the adsorbent on Sb (III) in different types of test water was tested. The state parameters of different types of natural water and the test results of Sb (III) removal are shown in Table 1. Figure 8 shown.

[0077] Table 1 Physical and chemical properties of natural water

[0078]

[0079] Depend on Figure 8 It can be seen that under different types of natural water conditions, 20% CeO x-The adsorption effect of iron ore composite materials on Sb(III) is almost consistent, indicating that this composite adsorbent has extremely strong stability and is suitable for a variety of sewage treatment scenarios.

[0080] (5) Experiment on the removal of Sb(III) in the presence of different anions and cations in water

[0081] Several groups of test water bodies containing Sb(III) were prepared (the initial concentration of Sb(III) in the test water bodies was 12 mg / L), and the coexisting ion Cl was added to each group of test water bodies at a concentration of 45 mg / L. - 、SO4 2- PO4 3- 、NO3 - , Ca 2+ 、Zn 2+ 、Na + , K + Mg 2+ , adjust the pH to 7, then add a certain amount of the material obtained in Example 1 as an adsorbent, and make the concentration of the adsorbent 1g / L, react at room temperature and pressure for 1h, test the treatment effect of different adsorbents on Sb(III) in water, the test results are as follows Figure 9 shown.

[0082] Depend on Figure 9 It can be seen that in the presence of different anions and cations, 20% CeO x - Iron ore composites have almost the same adsorption effect on Sb(III), but the adsorption of PO4 3- and Zn 2+ Under the presence of , the adsorption effect was slightly weakened, which was attributed to the competition between ions.

[0083] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A CeO x The quantum dot-iron ore composite material is characterized by: The composite material includes a natural siderite matrix and CeO2 loaded on the siderite matrix. x Quantum dots.

2. A CeO according to claim 1 x The quantum dot-iron ore composite material is characterized by: According to the theoretical mass percentage, the CeO x In quantum dot-iron ore composites, CeO x The content is 1%-40%.

3. A CeO according to any one of claims 1-2 x Preparation method of quantum dot-iron ore composite material, using precipitation-roasting method to load CeO on the surface of siderite matrix x , characterized in that, The following steps are involved: (1) Grinding natural siderite into powder, sieving and setting aside; (2) adding cetyltrimethylammonium bromide to the cerium nitrate hexahydrate solution, and mixing by ultrasonication to obtain a mixed solution; (3) adding natural siderite powder to the mixed solution, stirring evenly and ultrasonically treating the mixture, then adding NH3·H2O dropwise to adjust the pH to 10, and obtaining the product after the reaction is complete; (4) The product is filtered and washed until there are no ions attached to the surface, and then dried and calcined.

4. A CeO according to claim 3 x The preparation method of quantum dot-iron ore composite material is characterized in that: In the step (2), the ultrasonic mixing time is 30-60 min.

5. A CeO according to claim 3 x The preparation method of quantum dot-iron ore composite material is characterized in that: In the step (3), the calcination treatment is specifically as follows: heating the product to 350-550° C. at a heating rate of 3-10° C. / min, and keeping the temperature for 2-5 hours.

6. A CeO according to any one of claims 1-2 x Application of quantum dot-iron ore composite materials in treating Sb(III)-containing wastewater.

7. A Sb(III) removal adsorbent, characterized in that: Comprising CeO as described in any one of claims 1-2 x Quantum dot-iron ore composites.

8. A method for removing Sb(III) from wastewater, characterized in that The method comprises: adding CeO as described in any one of claims 1-2 x The quantum dot-iron ore composite material or the Sb(III) adsorbent as claimed in claim 7 is put into the wastewater containing Sb(III) and used in Ce 4+ / Ce 3+ and Fe 2+ / Fe 3+ Under the joint action of electron pairs, Sb(III) oxidation adsorption is achieved.

9. A method for removing Sb(III) from wastewater according to claim 8, characterized in that: The CeO x The effective concentration of the quantum dot-iron ore composite material or the Sb(III) removal adsorbent in wastewater is 0.5 g / L-5.0 g / L.

10. The method for removing Sb(III) from wastewater according to claim 8, characterized in that: The pH value of the wastewater is 3-9.

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