Preparation method of cobalt-doped lanthanum titanate perovskite material and application of cobalt-doped lanthanum titanate perovskite material in removal of sulfamethoxazole in water

Abstract

The invention discloses a preparation method of a cobalt-doped lanthanum titanate perovskite material and application of the cobalt-doped lanthanum titanate perovskite material in removal of sulfamethoxazole in water, and relates to the technical field of treatment of sulfamethoxazole in wastewater. The preparation method comprises the following steps: ultrasonically mixing titanium inorganic salt, lanthanum inorganic salt and cobalt inorganic salt to obtain a mixed solution, adding a sodium hydroxide solution, fully stirring, transferring into a high-pressure reaction kettle, and carrying out hydrothermal reaction. By controlling the molar ratio of the cobalt inorganic salt to the lanthanum inorganic salt, lanthanum titanate perovskite materials (Co / LTO) with different cobalt doping amounts can be obtained. Under the condition that the prepared cobalt-doped lanthanum titanate perovskite material is combined with peroxymonosulfate, efficient removal of sulfamethoxazole in water is achieved, the method has the advantages that the removal effect is slightly affected by the pH value, various inorganic anions, humic acid and other factors, and the material can be reused after being recycled and washed.

Description

Technical Field

[0001] The present invention relates to the technical field of sulfamethoxazole treatment in wastewater, and in particular to a preparation method of a cobalt-doped lanthanum titanate perovskite material and application of the material in removing sulfamethoxazole from water. Background Art

[0002] With the rapid development of medical technology, many diseases that were once difficult to cure have been conquered, among which the research and development and production of antibiotics are particularly prominent. With the continuous emergence of new antibiotics, bacterial infections have been brought under unprecedented control, and the use of antibiotics has become more and more widespread. In particular, classic antibiotics such as sulfamethoxazole (SMX) are difficult to be naturally decomposed in water bodies due to their stable chemical properties. They exist in rivers, lakes and groundwater systems for a long time, seriously endangering the safety and health of humans and the environment. Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) are a very promising water treatment technology. Therefore, how to efficiently remove sulfamethoxazole and even further mineralize pollutants is of great significance.

[0003] In recent years, metal redox (M n+ / M (n-1)+ ) show high activity in PMS activation in heterogeneous catalytic reactions of cobalt-based materials, but there is a problem of metal leaching. The structurally stable perovskite oxides provide an opportunity to design highly active PMS activators through composition customization. Manipulation of A / B sites and oxygen vacancies (V O ) can modulate the surface physicochemical properties of perovskites, which has been shown to be beneficial for PMS activation. Furthermore, given the great flexibility of the perovskite structure (ABO3) in simultaneously adjusting both electronic and surface structures, it may be a promising candidate for studying the dynamic evolution of interfacial reactions and the regulation of stable active sites. Inspired by these considerations, the present invention develops a perovskite oxide material by doping Co onto La2Ti2O7 two-dimensional ultrathin nanosheets (Co / LTO), achieving efficient PMS activation while minimizing metal leaching and ensuring catalyst stability. Summary of the Invention

[0004] In view of this, the present invention provides a preparation method of a cobalt-doped lanthanum titanate perovskite material and its application in removing sulfamethoxazole from water, which can achieve efficient removal of sulfamethoxazole from water.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing a cobalt-doped lanthanum titanate perovskite material comprises ultrasonically mixing a titanium inorganic salt, a lanthanum inorganic salt, and a cobalt inorganic salt to obtain a mixed solution, adding a sodium hydroxide solution, stirring thoroughly, and then transferring the solution to a high-pressure reactor for a hydrothermal reaction to obtain the final product. Lanthanum titanate perovskite materials (Co / LTO) with different cobalt doping amounts can be obtained by controlling the molar ratio of the cobalt inorganic salt to the lanthanum inorganic salt.

[0007] As a preferred technical solution of the present invention, a titanium inorganic salt, a lanthanum inorganic salt and a cobalt inorganic salt are ultrasonically mixed to obtain a mixed solution, and a sodium hydroxide solution is added and stirred thoroughly, wherein the titanium inorganic salt is titanium sulfate with a purity of >96%, and the addition amount is preferably 1 to 4 mmol, more preferably 1 to 3 mmol, and the final amount is preferably 2 mmol; the lanthanum inorganic salt is lanthanum nitrate with a purity of >99%, and the addition amount is preferably 1.8 to 2 mmol, more preferably 1.8 to 1.9 mmol, and the final amount is preferably 1.84 mmol; the cobalt inorganic salt is cobalt nitrate with a purity of >99%, and the addition amount is preferably 0.01 to 0.2 mmol, more preferably 0.1 to 0.2 mmol, and the final amount is preferably 0.16 mmol; the concentration of the sodium hydroxide solution is 2 mol / L, and the addition amount is preferably 0.01 to 20 mL; more preferably 5 to 15 mL, and the final amount is preferably 10 mL.

[0008] As a preferred technical solution of the present invention, after thorough stirring, the mixture is transferred to a high-pressure reactor for a hydrothermal reaction to obtain a cobalt-doped lanthanum titanate perovskite material. The hydrothermal reaction time is preferably 12 to 36 hours, more preferably 24 hours. The hydrothermal reaction temperature is preferably 220 to 240°C, more preferably 230°C.

[0009] As a preferred technical solution of the present invention, after the hydrothermal reaction is completed, the product is centrifuged, washed, and dried to obtain a cobalt-doped lanthanum titanate perovskite material. The washing conditions are: three washes each with ultrapure water and ethanol.

[0010] The present invention also proposes the use of this cobalt-doped lanthanum titanate perovskite material in removing sulfamethoxazole from water, specifically: adding the cobalt-doped lanthanum titanate perovskite material to water containing sulfamethoxazole, stirring for a period of time to achieve adsorption-desorption equilibrium, then adding peroxymonosulfate and continuing to stir to achieve the removal of sulfamethoxazole from the water; after removal, the cobalt-doped lanthanum titanate perovskite material in the system is recovered and reused through centrifugation, washing, and drying.

[0011] The peroxymonosulfate is preferably KHSO5, and the dosage is preferably 0.5 to 2 mmol / L, more preferably 1 mmol / L. The concentration of sulfamethoxazole in the system is preferably 5 to 50 mg / L, more preferably 10 mg / L. The dosage of the cobalt-doped lanthanum titanate perovskite material is preferably 0.1 to 0.5 g / L, more preferably 0.4 g / L.

[0012] In the present invention, the cobalt-doped lanthanum titanate perovskite material can be used multiple times. Specifically, the cobalt-doped lanthanum titanate perovskite material can be reused after being washed with deionized water.

[0013] The present invention combines cobalt-doped lanthanum titanate perovskite with peroxymonosulfate to achieve efficient removal of sulfamethoxazole in water, and the material can be recycled and reused after washing. Compared with the prior art, the present invention has the following advantages:

[0014] 1. Cobalt-doped lanthanum titanate perovskite materials can be synthesized through simple hydrothermal method.

[0015] 2. It can achieve efficient and rapid removal of sulfamethoxazole.

[0016] 3. Cobalt-doped lanthanum titanate perovskite materials can be reused after recycling and washing.

[0017] 4. The removal efficiency is less affected by common inorganic anions and humic acid and other substances, and sulfamethoxazole can be completely removed in Chaohu water and tap water. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic flow chart of a method for removing sulfamethoxazole from water using cobalt-doped lanthanum titanate perovskite material.

[0019] Figure 2 These are the phase characterization results of the synthesized cobalt-doped lanthanum titanate perovskite material.

[0020] Figure 3 This is a scanning electron microscope image of the synthesized cobalt-doped lanthanum titanate perovskite material.

[0021] Figure 4 Transmission electron micrograph of the synthesized cobalt-doped lanthanum titanate perovskite material.

[0022] Figure 5 The removal rate of sulfamethoxazole in water when lanthanum titanate perovskite materials doped with different cobalt contents are added; the concentration of sulfamethoxazole is 10 mg / L, the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4 g / L, and the dosage of peroxymonosulfate is 1 mmol / L.

[0023] Figure 6 The removal rate of sulfamethoxazole in water when the dosage of cobalt-doped lanthanum titanate perovskite material is different; the concentration of sulfamethoxazole is 10 mg / L, and the dosage of peroxymonosulfate is 1 mmol / L.

[0024] Figure 7The removal rate of sulfamethoxazole in water at different dosages of persulfate; the concentration of sulfamethoxazole is 10 mg / L, and the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4 g / L.

[0025] Figure 8 The removal rate of sulfamethoxazole in water when the dosage of sulfamethoxazole is different; the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4 g / L, and the dosage of peroxymonosulfate is 1 mmol / L.

[0026] Figure 9 is the removal rate of sulfamethoxazole in water at different initial pH values of the solution; the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4 g / L, the concentration of sulfamethoxazole is 10 mg / L, and the dosage of peroxymonosulfate is 1 mmol / L.

[0027] Figure 10 is the removal rate of sulfamethoxazole in water in the presence of anions and humic acid; the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4 g / L, the concentration of sulfamethoxazole is 10 mg / L, and the dosage of peroxymonosulfate is 1 mmol / L.

[0028] Figure 11 The invention relates to removing sulfamethoxazole from water by recycling the cobalt-doped lanthanum titanate perovskite material; wherein the concentration of sulfamethoxazole is 10 mg / L, the dosage of the cobalt-doped lanthanum titanate perovskite material is 0.4 g / L, and the dosage of peroxymonosulfate is 1 mmol / L. DETAILED DESCRIPTION

[0029] The preparation method of a cobalt-doped lanthanum titanate perovskite material and its application in removing sulfamethoxazole in water are further described in detail below with reference to the examples and drawings.

[0030] See also Figure 1 As shown, the present invention provides a preparation method of a cobalt-doped lanthanum titanate perovskite material and its application in removing sulfamethoxazole from water. The cobalt-doped lanthanum titanate perovskite material is added to water containing sulfamethoxazole, stirred for a period of time to reach adsorption-desorption equilibrium, and then peroxymonosulfate is added and stirred continuously to achieve the removal of sulfamethoxazole from the water.

[0031] Example 1

[0032] Preparation of Cobalt-doped Lanthanum Titanate Perovskite Materials

[0033] First, add 2 mmol Ti(SO4)2, x mmol Co(NO3)2·6H2O, and 2-x mmol La(NO3)3·6H2O to a clean 50 mL beaker. Then, add 10 mL of ultrapure water and sonicate to dissolve them. Then, slowly add 10 mL of 2 mol / L NaOH solution dropwise to form a uniform suspension. Stir at 850 rpm / min for 4 hours. Finally, transfer the mixture to a Teflon-lined stainless steel autoclave and maintain it at 230°C for 24 hours. The resulting solid is immediately washed and dried at 60°C with ultrapure water and ethanol.

[0034] The above x is set to 0, 0.04, 0.1, 0.16, and 0.2, respectively, and the prepared products are recorded as LTO, 2% Co / LTO, 5% Co / LTO, 8% Co / LTO, and 10% Co / LTO, respectively.

[0035] Figure 2 The results of the phase characterization of the cobalt-doped lanthanum titanate perovskite material synthesized by the method described in this example are shown in FIG. Figure 2 It can be seen that Example 1 prepared a variety of cobalt-doped lanthanum titanate perovskite materials with different Co doping ratios.

[0036] Figure 3 This is a scanning electron microscope photograph of the cobalt-doped lanthanum titanate perovskite material synthesized by the method described in this example. Figure 4 This is a transmission electron microscope photo of the cobalt-doped lanthanum titanate perovskite material synthesized by the method described in this example. Figure 3 and 4 It can be seen that the prepared cobalt-doped lanthanum titanate perovskite material has a nanosheet structure.

[0037] Example 2

[0038] Application of cobalt-doped lanthanum titanate perovskite material in removing sulfamethoxazole from water

[0039] The various cobalt-doped lanthanum titanate perovskite materials obtained in Example 1 were added to a solution containing 10 mg / L sulfamethoxazole at a dosage of 0.4 g / L, ultrasonically dispersed, and stirred at 650 rpm for 30 minutes to achieve adsorption-desorption equilibrium. Peroxymonosulfate (KHSO5, the same below) was added for activation at a dosage of 1 mmol / L. Stirred at 650 rpm. The results are shown in FIG. Figure 5 , Figure 5 The removal rate of sulfamethoxazole in water when different cobalt-doped lanthanum titanate perovskite materials are added. When the cobalt doping amount is 0.16 mmol, the cobalt-doped lanthanum titanate perovskite material 8% Co / LTO has the highest removal rate of sulfamethoxazole, and the removal rate of sulfamethoxazole can reach 99% within 10 minutes.

[0040] Example 3

[0041] Application of cobalt-doped lanthanum titanate perovskite materials in removing sulfamethoxazole from water under various dosage conditions

[0042] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained from Example 2 was added to a solution containing 10 mg / L sulfamethoxazole at different dosages (0-0.5 g / L) and ultrasonically dispersed. Stirring was performed at 650 rpm for 30 minutes to achieve adsorption-desorption equilibrium. Permonosulfate was then added at a dosage of 1 mmol / L. The stirring speed was maintained at 650 rpm. The results are shown in FIG. Figure 6 , Figure 6 The removal rate of sulfamethoxazole in water at different dosages of cobalt-doped lanthanum titanate perovskite material according to the scheme described in this embodiment. As can be seen from the figure, when the dosage of cobalt-doped lanthanum titanate perovskite material is 0g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 2.3%; when the dosage of cobalt-doped lanthanum titanate perovskite material is 0.1g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 13.5%; when the dosage of cobalt-doped lanthanum titanate perovskite material is 0.2g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 50.1%; when the dosage of cobalt-doped lanthanum titanate perovskite material is 0.3g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 77.8%; when the dosage of cobalt-doped lanthanum titanate perovskite material is 0.4g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 99.2%; when the dosage of cobalt-doped lanthanum titanate perovskite material is 0.5g / L, the removal rate of sulfamethoxazole within 10 minutes can reach 99.2%.

[0043] Example 4

[0044] Application of cobalt-doped lanthanum titanate perovskite materials in removing sulfamethoxazole from water under various peroxymonosulfate dosage conditions

[0045] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained from Example 2 was added to a solution containing 10 mg / L sulfamethoxazole at a dosage of 0.4 g / L and ultrasonically dispersed. Stirring was performed at 650 rpm for 30 minutes to achieve adsorption-desorption equilibrium. Then, different amounts of peroxymonosulfate (0.2 to 2 mmol / L) were added. The stirring speed was maintained at 650 rpm. The results are shown in FIG. Figure 7 , Figure 7The removal rate of sulfamethoxazole in water at different peroxymonosulfate dosages according to the scheme described in this embodiment is as follows. As can be seen in the figure, when the peroxymonosulfate dosage is 0.2mmol / L, the removal rate of sulfamethoxazole in 10 minutes can reach 55.1%; when the peroxymonosulfate dosage is 0.75mmol / L, the removal rate of sulfamethoxazole in 10 minutes can reach 91.7%; when the peroxymonosulfate dosage is 1mmol / L, the removal rate of sulfamethoxazole in 10 minutes can reach 99.2%; when the peroxymonosulfate dosage is 1.5mmol / L, the removal rate of sulfamethoxazole in 10 minutes can reach 97.8%; when the peroxymonosulfate dosage is 2mmol / L, the removal rate of sulfamethoxazole in 10 minutes can reach 95.6%.

[0046] Example 5

[0047] Application of cobalt-doped lanthanum titanate perovskite materials in removing sulfamethoxazole from water under different sulfamethoxazole dosage conditions

[0048] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained from Example 2 was added to a solution containing sulfamethoxazole at different concentrations (5-50 mg / L) at a dosage of 0.4 g / L and ultrasonically dispersed. Stirred at 650 rpm for 30 minutes to achieve adsorption-desorption equilibrium. Permonosulfate was then added at a dosage of 1 mmol / L. The stirring speed was maintained at 650 rpm. The results are shown in FIG. Figure 8 , Figure 8 For the scheme described in the present embodiment, the removal rate of sulfamethoxazole in water when the concentration of sulfamethoxazole is different. As can be seen in the figure, when the concentration of sulfamethoxazole is 5mg / L, the removal rate of sulfamethoxazole in 4min can reach 99.1%; when the concentration of sulfamethoxazole is 10mg / L, the removal rate of sulfamethoxazole in 10min can reach 99.2%; when the concentration of sulfamethoxazole is 20mg / L, the removal rate of sulfamethoxazole in 10min can reach 75.5%; when the concentration of sulfamethoxazole is 30mg / L, the removal rate of sulfamethoxazole in 10min can reach 57%; when the concentration of sulfamethoxazole is 40mg / L, the removal rate of sulfamethoxazole in 10min can reach 48.1%; when the concentration of sulfamethoxazole is 50mg / L, the removal rate of sulfamethoxazole in 10min can reach 42.3%.

[0049] Example 6

[0050] Application of cobalt-doped lanthanum titanate perovskite materials in removing sulfamethoxazole from water under different pH conditions

[0051] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained from Example 2 was added to a solution treated with 10 mg / L sulfamethoxazole at a dosage of 0.4 g / L. The solution was adjusted to different pH values (5 to 11) and ultrasonically dispersed at 650 rpm for 30 minutes to achieve adsorption-desorption equilibrium. Peroxymonosulfate was added for activation at a dosage of 1 mmol / L. The stirring speed was maintained at 650 rpm. The results are shown in Table 1. Figure 9 , Figure 9 The removal rate of sulfamethoxazole in water at different pH values according to the scheme described in this embodiment is shown in the figure. As can be seen in the figure, at a pH of 5, the removal rate of sulfamethoxazole in 10 minutes can reach 97.9%; at a pH of 7, the removal rate of sulfamethoxazole in 10 minutes can reach 99%; at a pH of 9, the removal rate of sulfamethoxazole in 10 minutes can reach 99.2%; and at a pH of 11, the removal rate of sulfamethoxazole in 10 minutes can reach 97.7%.

[0052] Example 7

[0053] Application of cobalt-doped lanthanum titanate perovskite materials in the removal of sulfamethoxazole from water in the presence of anions and humic acid

[0054] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained by screening in Example 2 was added to a solution treated with 10 mg / L sulfamethoxazole at a dosage of 0.4 g / L. The anion concentration was 2 mmol / L (the corresponding cation was sodium ion), the humic acid concentration was 2 mg / L, and ultrasonic dispersion was performed. Stir at 650 rpm for 30 minutes to reach adsorption-desorption equilibrium. Permonosulfate was then added at a dosage of 1 mmol / L. The stirring speed was maintained at 650 rpm. The results are shown in FIG. Figure 10 , Figure 10 The removal rate of sulfamethoxazole in water in the presence of anions according to the scheme described in this embodiment is shown in the figure. As can be seen from the figure, when the anions are chloride ions, sulfate ions, and nitrate ions, the removal rate of sulfamethoxazole can reach over 99% within 10 minutes; when the anion is bicarbonate ion, the removal rate of sulfamethoxazole can reach 88.5% within 10 minutes; when the anion is dihydrogen phosphate ion, the removal rate of sulfamethoxazole can reach 58% within 10 minutes; and when humic acid is present, the removal rate of sulfamethoxazole can reach 98.6% within 10 minutes.

[0055] Example 8

[0056] Application of cobalt-doped lanthanum titanate perovskite materials in removing sulfamethoxazole from water after multiple cycles

[0057] The optimal cobalt-doped lanthanum titanate perovskite material 8% Co / LTO obtained by screening in Example 2 can be washed and dried after use according to the scheme described in Example 2. Repeating the process of Example 2 once is considered as one cycle. Figure 11 , Figure 11 According to the scheme described in this embodiment, the cobalt-doped lanthanum titanate perovskite material was used and cycled 5 times, and nearly 100% removal of sulfamethoxazole was still achieved within 30 minutes.

[0058] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a cobalt-doped lanthanum titanate perovskite material, characterized in that: Titanium inorganic salt, lanthanum inorganic salt and cobalt inorganic salt are ultrasonically mixed to obtain a mixed solution, sodium hydroxide solution is added and stirred thoroughly, and then transferred to a high-pressure reactor for hydrothermal reaction to finally obtain the material; by controlling the molar ratio of cobalt inorganic salt to lanthanum inorganic salt, lanthanum titanate perovskite materials (Co / LTO) with different cobalt doping amounts can be obtained.

2. The preparation method according to claim 1, wherein The titanium inorganic salt is titanium sulfate with a purity greater than 96%, the cobalt inorganic salt is cobalt nitrate with a purity greater than 99%, and the lanthanum inorganic salt is lanthanum nitrate with a purity greater than 99%. The molar ratio of the cobalt inorganic salt to the lanthanum inorganic salt is x:2-x, wherein x is 0.01-0.

2.

3. The preparation method according to claim 1, wherein The hydrothermal reaction temperature is 220-240° C., the reaction time is 12-36 hours, and the reaction obtains a cobalt-doped lanthanum titanate perovskite material.

4. Use of the cobalt-doped lanthanum titanate perovskite material prepared by the method according to any one of claims 1 to 3 in removing sulfamethoxazole from water, characterized in that: Here are the steps: Cobalt-doped lanthanum titanate perovskite material was added to water containing sulfamethoxazole, stirred for a period of time to reach adsorption-desorption equilibrium, and then peroxymonosulfate was added and stirred continuously to achieve the removal of sulfamethoxazole in the water; After removal, the cobalt-doped lanthanum titanate perovskite material in the system is recovered and reused through centrifugation, washing and drying.

5. The use according to claim 4, characterized in that The dosage of the cobalt-doped lanthanum titanate perovskite material in the system is 0.1-0.5 g / L.

6. The use according to claim 4, characterized in that The peroxymonosulfate is KHSO5, and its dosage in the system is 0.2-2 mmol / L.

7. The use according to claim 4, characterized in that The concentration of sulfamethoxazole in the system is 5-50 mg / L.

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