Preparation method of mesoporous iron phosphate

Abstract

The invention relates to the technical field of preparation methods of mesoporous iron phosphate, in particular to a preparation method of mesoporous iron phosphate, which comprises the following steps: (1) preparation of a solution A: weighing 0.03-0.06 mol of dodecyl phosphate, dissolving the dodecyl phosphate in deionized water with a first preset volume, adding 8-12 mL of absolute ethyl alcohol, stirring at the temperature of 50-60 DEG C for 1-2 hours, and filtering to obtain the solution A; after fully mixing, stirring at a first preset temperature for a first preset time to obtain a solution A; (2) preparation of a solution B: respectively weighing FeCl3. 6H2O and H3PO4 according to the molar ratio of Fe < 3 + > to PO4 < 3-> being 1: 1, and dissolving the FeCl3. 6H2O and the H3PO4 in deionized water with a second preset volume to obtain the solution B; (3) preparing a solution C: mixing the solution A and the solution B, and adjusting the pH of the mixed solution to be neutral to obtain the solution C; (4) preparing a precursor, namely stirring the solution C at a second preset temperature for a second preset time, and drying in a drying oven to obtain the precursor; and (5) calcining: sintering the precursor to obtain mesoporous FePO4.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mesoporous iron phosphate preparation, in particular to a mesoporous iron phosphate preparation method. BACKGROUND

[0002] Heavy metal pollution has become one of the serious environmental problems worldwide. Heavy metals such as mercury (Hg), lead (Pb), cadmium (Cd), chromium (Cr) and arsenic (As) are discharged into the environment in large quantities due to industrial activities such as mining, metallurgy, electroplating, chemical production, etc. These heavy metals are difficult to be biodegraded and will continue to accumulate in soil and water. Heavy metal pollution can lead to water quality deterioration, harm aquatic life, and through the food chain, ultimately pose a serious threat to human health and cause various diseases.

[0003] In the treatment of heavy metal pollution, adsorption method has become one of the widely used methods due to its simple operation, low cost and significant effect. Although traditional adsorption materials such as activated carbon, zeolite and ion exchange resin can adsorb heavy metal ions to some extent, they have many limitations.

[0004] The patent with application number 202111282441.1 discloses a heavy metal ion adsorption material and its preparation method. The preparation process of the heavy metal ion adsorption material is relatively complex, and organic solvents such as diethyl ether, aviation kerosene and n-hexane are used in the preparation process. These solvents themselves have environmental risks, and the cost of solvent recovery or treatment increases, and special protective measures are required for operation. SUMMARY

[0005] In view of the deficiencies or problems existing in the prior art, the present disclosure provides a mesoporous iron phosphate preparation method. The preparation method is simple, and the mesoporous iron phosphate prepared has excellent adsorption performance for heavy metal ions in water.

[0006] The technical solution adopted by the present disclosure to solve the above technical problems is: a mesoporous iron phosphate preparation method, comprising the following steps: (1) Preparation of solution A: weigh 0.03-0.06 mol of dodecyl phosphate, dissolve it in a first predetermined volume of deionized water, and add 8-12 mL of anhydrous ethanol. After mixing thoroughly, place it in a first predetermined temperature for a first predetermined time to obtain solution A; (2) Preparation of solution B: according to the molar ratio of Fe 3+ to PO4 3- is 1:1, weigh FeCl3·6H2O and H3PO4 respectively, and dissolve them in a second predetermined volume of deionized water to obtain solution B; (3) Preparation of solution C: mix solution A and solution B, and adjust the pH of the mixed solution to neutral to obtain solution C; (4) Preparation of the precursor: the solution C is stirred at a second preset temperature for a second preset time, and then dried in a drying box to obtain the precursor; (5) Calcination: the precursor is sintered in a muffle furnace for a period of time to obtain mesoporous FePO4.

[0007] In the first step, the first preset volume is 35-45 mL; the first preset temperature is 50-60 DEG C; and the first preset time is 1-2 h.

[0008] In the second step, the second preset volume is 35-45 mL.

[0009] In the third step, the pH of the mixed solution is adjusted to neutral by using ammonia.

[0010] In the fourth step, the second preset temperature is 50-60 DEG C; and the second preset time is 15-22 h.

[0011] The drying temperature of the drying box is 60-80 DEG C, and the drying time is 12-24 h.

[0012] In the fifth step, the sintering temperature of the precursor in the muffle furnace is 300-600 DEG C; and the sintering time is 2-6 h.

[0013] Compared with the prior art, the application has the following beneficial effects: The application forms a mesoporous structure by using a surfactant (dodecyl phosphate) template method, which significantly improves the specific surface area and active site density of FePO4. The mesoporous channels accelerate the diffusion of heavy metal ions, and the adsorption efficiency for low-concentration ions is higher. The application uses an aqueous phase system, and there is no flammable or toxic organic solvent, so the whole preparation process is safer and more environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is an SEM image of mesoporous FePO4 in Example 1 of the application; Figure 2 It is an SEM image of mesoporous FePO4 in Example 2 of the application; Figure 3 It is an SEM image of mesoporous FePO4 in Example 3 of the application; Figure 4 It is an SEM image of mesoporous FePO4 in Example 4 of the application; Figure 5 It is an SEM image of mesoporous FePO4 in Example 5 of the application; Figure 6 It is an SEM image of mesoporous FePO4 in Example 6 of the application; Figure 7 SEM image of mesoporous FePO4in Example 7 of the present application; Figure 8 SEM image of mesoporous FePO4in Example 8 of the present application. DETAILED DESCRIPTION

[0015] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is described in detail, clearly and completely below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present disclosure and do not limit the present disclosure.

[0016] A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: weigh 0.03-0.06 mol of dodecyl phosphate, dissolve it in 35-45 mL of deionized water, and add 8-12 mL of anhydrous ethanol, mix thoroughly, and then place it in a constant temperature water bath, stir at a temperature of 50-60°C for 1-2 h, and obtain solution A; (2) Preparation of solution B: according to the molar ratio of Fe 3+ to PO4 3- , weigh FeCl3·6H2O and H3PO4 respectively, and dissolve them in 35-45 mL of deionized water to obtain solution B; (3) Preparation of solution C: mix solution A and solution B, and use ammonia water to adjust the pH of the mixed solution to neutral to obtain solution C; (4) Preparation of precursor: place solution C in a constant temperature water bath and stir at a temperature of 50-60°C for 15-22 h, and then place it in a drying oven at a temperature of 60-80°C for 12-24 h to obtain the precursor; (5) Calcination: place the precursor in a muffle furnace and sinter at a temperature of 300-600°C for 2-6 h to obtain mesoporous FePO4.

[0017] Dodecyl phosphate (MDP) is a surfactant, whose molecule contains a hydrophilic head (phosphate group) and a hydrophobic tail (dodecyl chain). In step (1), after dissolving it in deionized water and mixing with anhydrous ethanol, stirring at a temperature of 50-60°C for 1-2 h helps the surfactant molecules to fully dissolve, diffuse and reach a dynamic balance state of self-assembly, forming a uniform and stable micellar solution.

[0018] Among them, anhydrous ethanol not only helps to dissolve the surfactant, especially when the concentration is high or the temperature is low, to prevent it from precipitating or forming a gel, but also changes the polarity of water, which helps to form smaller and more uniform micelles.

[0019] Iron and phosphorus sources are provided by FeCl3·6H2O and H3PO4, respectively, according to Fe... 3+ With PO4 3- The molar ratio of FeCl3·6H2O and H3PO4 is 1:1, and these are weighed separately to avoid the formation of impurity phases (such as Fe2O3 or Fe3(PO4)2).

[0020] Fe 3+ Under acidic conditions, it is difficult for Fe to effectively condense with phosphorus sources to form stable Fe-OP bonds. A neutral pH environment (usually close to 7) is favorable for Fe... 3+ With PO4 3- The hydrolysis of the surfactant micelles and their condensation reactions form an inorganic FePO4 network framework. Furthermore, a neutral pH helps maintain the stability of the surfactant micelles (avoiding destruction under strong acids and bases) and optimizes the electrostatic interactions between the micelle surface charge and inorganic species, promoting the co-assembly of the inorganic network around the micelle template to form ordered or disordered mesoscopic structures (with micelles encapsulated within the inorganic network).

[0021] In step (4), stirring solution C at 50-60℃ for 15-22 hours provides sufficient time and a suitable temperature for Fe to... 3+ and PO4 3- The ions undergo complete hydrolysis and condensation to form a more complete and highly cross-linked inorganic iron phosphate network, thereby promoting the formation of a more ordered and stable organic-inorganic composite mesostructure.

[0022] In step (4), the drying process initially solidifies the gel, fixing the composite structure composed of the surfactant template and the inorganic iron phosphate network, preventing collapse during subsequent transfer and calcination. Controlling the drying temperature at 60-80℃ allows for gentle solvent evaporation, solidifying the structure without damaging the template.

[0023] In step (5), the precursor is placed in a muffle furnace and sintered at a temperature of 300-600℃ for 2-6 hours. This not only oxidizes and burns away the organic surfactants (dodecyl phosphate) and their decomposition products (carbon, etc.) wrapped in the inorganic network, but also allows the inorganic skeleton to further condense and densify at high temperature, thereby enhancing its thermal and mechanical stability and fixing and stabilizing the mesoporous channels left by the template.

[0024] Example 1 A method for preparing mesoporous iron phosphate includes the following steps: (1) Preparation of solution A: Weigh 0.04 mol of dodecyl phosphate, dissolve it in 40 mL of deionized water, add 10 mL of anhydrous ethanol, mix thoroughly, place in a constant temperature water bath, and stir at 60 °C for 1 h to obtain solution A. (2) Preparation of solution B: 27.03 g of FeCl3 6H2O and 5.88 g of H3PO4 were weighed respectively and dissolved in 40 mL of deionized water to obtain solution B; (3) Preparation of solution C: solution A and solution B were mixed, and the pH of the mixed solution was adjusted to neutral using ammonia water to obtain solution C; (4) Preparation of precursor: solution C was placed in a constant temperature water bath at a temperature of 60°C and stirred for 18 h, and then placed in a drying oven at a temperature of 60°C and dried for 24 h to obtain a precursor; (5) Calcination: the precursor was placed in a muffle furnace and sintered at a temperature of 400°C for 3 h to obtain mesoporous FePO4.

[0025] The SEM image of mesoporous FePO4 in this example is shown in Figure 1 The appearance is very neat and similar to a rod, and the surface has a large number of small pores, has a large specific surface area and uniform pore size distribution, and the specific surface area is 49.4587 m 2 / g, and the pore size distribution ranges from 16 nm to 60 nm. The adsorption capacity of thallium ions in water is 185 mg / g, and the adsorption capacity of lead ions is greater than 260 mg / g.

[0026] Example 2 A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: 0.04 mol of dodecyl phosphate was weighed and dissolved in 40 mL of deionized water, and 10 mL of anhydrous ethanol was added, and after mixing, it was placed in a constant temperature water bath at a temperature of 60°C and stirred for 1 h to obtain solution A; (2) Preparation of solution B: 27.03 g of FeCl3 6H2O and 5.88 g of H3PO4 were weighed respectively and dissolved in 40 mL of deionized water to obtain solution B; (3) Preparation of solution C: solution A and solution B were mixed, and the pH of the mixed solution was adjusted to neutral using ammonia water to obtain solution C; (4) Preparation of precursor: solution C was placed in a constant temperature water bath at a temperature of 60°C and stirred for 18 h, and then placed in a drying oven at a temperature of 60°C and dried for 24 h to obtain a precursor; (5) Calcination: the precursor was placed in a muffle furnace and sintered at a temperature of 300°C for 3 h to obtain mesoporous FePO4.

[0027] The SEM image of mesoporous FePO4 in this example is shown in Figure 2 The appearance is very neat and similar to a rod, and the surface has a large number of small pores, has a large specific surface area and uniform pore size distribution, and the specific surface area is 49.4587 m 2The mesoporous FePO4 has a specific surface area of 46.8946 m2 / g, a pore size distribution range of 16 nm-81 nm, a thallium ion adsorption capacity of 130 mg / g, and a lead ion adsorption capacity of more than 200 mg / g.

[0028] Example 3 A method for preparing mesoporous FePO4 includes the following steps: (1) Preparation of solution A: 0.04 mol of dodecyl phosphate is weighed and dissolved in 40 mL of deionized water, and 10 mL of anhydrous ethanol is added. After being fully mixed, the solution is placed in a constant-temperature water bath and stirred at 60°C for 1 h to obtain solution A; (2) Preparation of solution B: 27.03 g of FeCl3·6H2O and 5.88 g of H3PO4 are weighed and dissolved in 40 mL of deionized water to obtain solution B; (3) Preparation of solution C: Solution A and solution B are mixed, and ammonia is used to adjust the pH of the mixed solution to neutral to obtain solution C; (4) Preparation of a precursor: Solution C is placed in a constant-temperature water bath and stirred at 60°C for 18 h, and then placed in a drying box and dried at 60°C for 24 h to obtain a precursor; (5) Calcination: The precursor is placed in a muffle furnace and sintered at 450°C for 3 h to obtain mesoporous FePO4.

[0029] The SEM image of the mesoporous FePO4 in this example is shown in Figure 3 The appearance of the mesoporous FePO4 is rod-shaped, the surface has a large number of small pores and uniform distribution, has a large specific surface area and uniform pore size distribution, and the specific surface area is 46.8946 m2 / g, the pore size distribution range is 16 nm-72 nm, the thallium ion adsorption capacity is 153 mg / g, and the lead ion adsorption capacity is more than 230 mg / g. 2 / g, the pore size distribution range is 16 nm~81 nm. Its adsorption capacity for thallium ions in water is 130 mg / g, and its adsorption capacity for lead ions is greater than 200 mg / g.

[0030] Example 4 A method for preparing mesoporous FePO4 includes the following steps: (1) Preparation of solution A: 0.04 mol of dodecyl phosphate is weighed and dissolved in 40 mL of deionized water, and 10 mL of anhydrous ethanol is added. After being fully mixed, the solution is placed in a constant-temperature water bath and stirred at 60°C for 1 h to obtain solution A; (2) Preparation of solution B: 27.03 g of FeCl3·6H2O and 5.88 g of H3PO4 are weighed and dissolved in 40 mL of deionized water to obtain solution B; (3) Preparation of solution C: Solution A and solution B are mixed, and ammonia is used to adjust the pH of the mixed solution to neutral to obtain solution C; (4) Preparation of the precursor: the solution C is placed in a constant temperature water bath and stirred at 60°C for 18h, and then placed in a drying oven and dried at 60°C for 24h to obtain the precursor; (5) Calcination: the precursor is placed in a muffle furnace and sintered at 500°C for 3h to obtain mesoporous FePO4.

[0031] The SEM image of the mesoporous FePO4 in this example is shown in Figure 4 The appearance is neat rod-shaped, the surface has small holes, and it has a large specific surface area and uniform pore size distribution. The specific surface area is 40.4587m 2 / g, and the pore size distribution range is 16nm~72nm. The adsorption capacity of thallium ions in water is 138 mg / g, and the adsorption capacity of lead ions is greater than 190 mg / g.

[0032] Example 5 A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: 0.03mol of dodecyl phosphate is weighed and dissolved in 35mL of deionized water, and 8mL of anhydrous ethanol is added. After mixing, it is placed in a constant temperature water bath and stirred at 50°C for 1.5h to obtain solution A; (2) Preparation of solution B: 27.03g of FeCl3·6H2O and 5.88g of H3PO4 are weighed and dissolved in 35mL of deionized water to obtain solution B; (3) Preparation of solution C: solution A and solution B are mixed, and the pH of the mixed solution is adjusted to neutral with ammonia water to obtain solution C; (4) Preparation of the precursor: the solution C is placed in a constant temperature water bath and stirred at 50°C for 15h, and then placed in a drying oven and dried at 80°C for 12h to obtain the precursor; (5) Calcination: the precursor is placed in a muffle furnace and sintered at 350°C for 6h to obtain mesoporous FePO4.

[0033] The SEM image of the mesoporous FePO4 in this example is shown in Figure 5 The appearance is neat rod-shaped, the surface has small holes, and it has a large specific surface area and uniform pore size distribution. The specific surface area is 40.4587m 2 / g, and the pore size distribution range is 16nm~72nm. The adsorption capacity of thallium ions in water is 138 mg / g, and the adsorption capacity of lead ions is greater than 190 mg / g.

[0034] Example 6 A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: 0.05 mol of dodecyl phosphate was weighed and dissolved in 45 mL of deionized water, and 12 mL of anhydrous ethanol was added, and after being fully mixed, it was placed in a constant-temperature water bath and stirred at a temperature of 55°C for 2 h to obtain solution A; (2) Preparation of solution B: 27.03 g of FeCl3·6H2O and 5.88 g of H3PO4 were weighed and dissolved in 36 mL of deionized water to obtain solution B; (3) Preparation of solution C: solution A and solution B were mixed, and the pH of the mixed solution was adjusted to neutral using ammonia water to obtain solution C; (4) Preparation of the precursor: solution C was placed in a constant-temperature water bath and stirred at a temperature of 55°C for 16 h, and then placed in a drying oven at a temperature of 70°C for 15 h to obtain the precursor; (5) Calcination: the precursor was placed in a muffle furnace and sintered at a temperature of 550°C for 5 h to obtain mesoporous FePO4.

[0035] The SEM image of mesoporous FePO4 in this example is shown in Figure 6 The appearance presents agglomerated short rods, and the surface has a large number of small pores, has a large specific surface area and uniform pore size distribution, and the specific surface area is 45.6398 m 2 / g, and the pore size distribution range is 18 nm~60 nm. Its adsorption capacity for water thallium ions is 157 mg / g, and the adsorption capacity for lead ions is greater than 230 mg / g.

[0036] Example 7 A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: 0.06 mol of dodecyl phosphate was weighed and dissolved in 45 mL of deionized water, and 9 mL of anhydrous ethanol was added, and after being fully mixed, it was placed in a constant-temperature water bath and stirred at a temperature of 52°C for 2 h to obtain solution A; (2) Preparation of solution B: 27.03 g of FeCl3·6H2O and 5.88 g of H3PO4 were weighed and dissolved in 45 mL of deionized water to obtain solution B; (3) Preparation of solution C: solution A and solution B were mixed, and the pH of the mixed solution was adjusted to neutral using ammonia water to obtain solution C; (4) Preparation of the precursor: solution C was placed in a constant-temperature water bath and stirred at a temperature of 50°C for 20 h, and then placed in a drying oven at a temperature of 75°C for 12 h to obtain the precursor; (5) Calcination: the precursor was placed in a muffle furnace and sintered at a temperature of 600°C for 2 h to obtain mesoporous FePO4.

[0037] The SEM image of mesoporous FePO4 in this example is shown in Figure 7 The appearance presents a large number of short rod-like agglomerates, and the surface has a large number of small pores, a large specific surface area and a uniform pore size distribution. The specific surface area is 42.7421 m 2 / g, and the pore size distribution range is 18 nm~80 nm. The adsorption capacity of thallium ions in water is 137 mg / g, and the adsorption capacity of lead ions is greater than 200 mg / g.

[0038] Example 8 A method for preparing mesoporous iron phosphate, comprising the following steps: (1) Preparation of solution A: 0.03 mol of dodecyl phosphate is weighed and dissolved in 35 mL of deionized water, and 11 mL of anhydrous ethanol is added. After mixing, it is placed in a constant temperature water bath and stirred at 58°C for 2h to obtain solution A; (2) Preparation of solution B: 27.03g of FeCl3·6H2O and 5.88g of H3PO4 are weighed and dissolved in 42 mL of deionized water to obtain solution B; (3) Preparation of solution C: Solution A and solution B are mixed, and the pH of the mixed solution is adjusted to neutral with ammonia water to obtain solution C; (4) Preparation of precursor: solution C is placed in a constant temperature water bath and stirred at 52°C for 22h, and then placed in a drying oven at 65°C for 18h to obtain a precursor; (5) Calcination: the precursor is placed in a muffle furnace and sintered at 300°C for 4h to obtain mesoporous FePO4.

[0039] The SEM image of mesoporous FePO4 in this example is shown in Figure 8 The appearance presents a large number of short rod-like agglomerates, and the surface has a large number of small pores, a large specific surface area and a uniform pore size distribution. The specific surface area is 42.7421 m 2 / g, and the pore size distribution range is 18 nm~80 nm. The adsorption capacity of thallium ions in water is 137 mg / g, and the adsorption capacity of lead ions is greater than 200 mg / g.

[0040] The above has been described in detail, and the principle and implementation of the application are described in this paper. The above example is only used to help understand the application and the core idea. It should be pointed out that for ordinary skilled persons in the technical field, without departing from the principle of the application, some improvements and modifications can be made to the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A method for preparing mesoporous iron phosphate, characterized in that, Includes the following steps: (1) Preparation of solution A: Weigh 0.03-0.06 mol of dodecyl phosphate, dissolve it in a first preset volume of deionized water, add 8-12 mL of anhydrous ethanol, mix thoroughly, and place at a first preset temperature for a first preset time to obtain solution A; (2) Preparation of solution B: According to Fe 3+ With PO4 3- The molar ratio of FeCl3·6H2O and H3PO4 is 1:

1. FeCl3·6H2O and H3PO4 are weighed out respectively and dissolved in a second preset volume of deionized water to obtain solution B. (3) Preparation of solution C: Mix solution A with solution B and adjust the pH of the mixed solution to neutral to obtain solution C; (4) Preparation of precursor: Place solution C at a second preset temperature and stir for a second preset time, then place it in a drying oven to dry and obtain the precursor; (5) Calcination: The precursor is placed in a muffle furnace and sintered for a period of time to obtain mesoporous FePO4.

2. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (1), the first preset volume is 35-45 mL.

3. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, The first preset temperature is 50-60℃; the first preset time is 1-2h.

4. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (2), the second preset volume is 35-45 mL.

5. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (3), ammonia is used to adjust the pH of the mixed solution to neutral.

6. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (4), the second preset temperature is 50-60℃; the second preset time is 15-22h.

7. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (4), the drying temperature of the drying oven is 60-80℃ and the drying time is 12-24h.

8. The method for preparing mesoporous iron phosphate according to claim 1, characterized in that, In step (5), the sintering temperature of the precursor in the muffle furnace is 300-600℃; the sintering time is 2-6h.

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