METHOD OF PREPARING LARGE-SIZE HIGH-POROSITY FE-DOPED PHOTOCATALYTIC POROUS MAGNETIC MICROSPHERES AND USES THEREOF

Abstract

A method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres, including: dissolving a soluble macromolecule in a distilled water to obtain a solution A having a concentration of 0.5-1.5 wt %; adding a photocatalyst to the solution A, and uniformly stirring the solution A to obtain a suspension B; mixing a saturated soluble ferric salt solution with the suspension B, and uniformly stirring the mixture to obtain a suspension C; dropwise adding the suspension C to a high-concentration alkali solution by a syringe equipped with a suitable needle size to form microspheres; ageing the reaction system and drying the formed microspheres after adding; calcining the dried microspheres at 600-1100 C.; cooling the calcined microspheres to obtain the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres.

Claims

1. A method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres, comprising: dissolving a soluble macromolecule in a distilled water to obtain a solution A having a concentration of 0.5-1.5 wt %; adding a photocatalyst to the solution A, and uniformly mixing the solution A and the photocatalyst under stirring to obtain a suspension B; mixing a saturated soluble ferric salt solution with the suspension B under stirring to obtain a suspension C; dropwise adding the suspension C to a high-concentration alkali solution by a syringe equipped with a needle of a suitable size to form microspheres; ageing and drying the microspheres; calcining the microspheres at 600-1100 C. for 30-120 minutes; and cooling the microspheres to obtain the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres.

2. The method of claim 1, wherein the soluble macromolecule is any one of a sesbania powder, a carboxymethyl cellulose and a guar gum.

3. The method of claim 1, wherein the photocatalyst is any one of a titanium dioxide, a lanthanum potassium titanate, a strontium titanate or a zinc oxide.

4. The method of claim 2, wherein the photocatalyst is any one of a titanium dioxide, a lanthanum potassium titanate, a strontium titanate or a zinc oxide.

5. The method of claim 1, wherein the suspension B has a solid content of 35-65 wt %

6. The method of claim 1, wherein the soluble ferric salt is any one of a ferric chloride or a ferric nitrate.

7. The method of claim 1, wherein in the soluble ferric salt solution, a molar ratio of Fe.sup.3+ ions to the photocatalyst is 15:100 to 45:100.

8. The preparation method of claim 1, wherein the alkali solution is any one of concentrated ammonia water, a saturated urea solution and a saturated hexamethylenetetramine solution.

9. The preparation method of claim 1, wherein an ageing time is 30-120 minutes, and a drying temperature is 60-80 C.

10. A use method of the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres of claim 1, comprising: applying the porous magnetic microspheres to catalytic degradation of an organic dye.

11. The use method of claim 10, wherein the organic dye is a methylene blue dye.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a flow chart showing a process for preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres according to the present invention.

[0028] FIG. 2 is a schematic diagram showing a specific process of dripping and pelleting in the preparation process of the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres according to the present invention.

[0029] FIG. 3 is a scanning electron microscope image of large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres according to an embodiment of the present invention.

[0030] FIG. 4 is an XRD pattern of the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres according to an embodiment of the present invention.

[0031] FIG. 5 is a graph showing a degradation rate versus time of the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres according to an embodiment of the present invention used for catalytic degradation of a methylene blue dye for the first time.

[0032] FIG. 6 is a diagram showing comparative degradation rates of the large-scale high-porosity Fe-doped photocatalytic porous magnetic microspheres according to an embodiment of the present invention repeatedly used for catalytic degradation of the methylene blue dye.

DETAILED DESCRIPTION OF EXAMPLES

[0033] Embodiments of the present invention are illustrated in detail as follows. The embodiments are on the basis of the technical solutions of the present invention, which gives a detailed method and a specific operation process. However, the scope of the present invention is not limited to the following embodiments.

[0034] According to the information of the present invention, various modifications of the present invention are easy to be made by those skilled in prior art without departing from the spirit and scope of the appended claims. It should be understood that the scope of the invention is not limited to the defined procedures, properties or components, because these embodiments and descriptions are merely illustrative of specific aspects of the invention. In fact, it is apparent to those skilled in prior art that various modifications of the embodiments of the invention are within the scope of the appended claims.

[0035] In order to better understand the invention but not to limit the scope of the invention, all numerical parameters representing dosages and percentages as well as other values used in the present invention should be understood in all instances as being attributed by the word about. Accordingly, unless otherwise stated, the numerical parameters set forth in the specification and the appended claims are approximations, which may vary depending on the desired properties. Each numerical parameter should at least be considered as being obtained based on the reported significant figures and conventional rounding method.

EXAMPLE 1

[0036] In the present embodiment, a method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres includes the following steps.

[0037] (1) sesbania powder (0.5 g) was dissolved in 100 mL of distilled water to obtain a solution A with a concentration of 0.5 wt %.

[0038] (2) titanium dioxide (TiO.sub.2, 35 g, 0.438 mol, molecular weight: 79.87) photocatalyst (abbreviated as P-25 below) was added to the solution A, and uniformly mixing under stirring to obtain a suspension B with a solid content of 35 wt %.

[0039] (3) saturated FeCl.sub.3 solution (11.5 mL, concentration: 92 g/100 mL) was uniformly mixed with the suspension B in step (2) under stirring to obtain a suspension C. The molar ratio of the Fe.sup.3+ ions and the titanium dioxide was 15:100.

[0040] (4) The suspension C was dropwise added to a concentrated ammonia water by a syringe equipped with a No. 6-sized needle to form microspheres. The microspheres were aged for 60 minutes and dried at 80 C.

[0041] (5) The microspheres dried in step (4) were calcined at 600 C. for 120 minutes to obtain the Fe-doped titanium dioxide photocatalytic porous magnetic microspheres.

[0042] FIG. 3 shows a scanning electron microscope (SEM) image of the porous magnetic microspheres according to an embodiment of the present invention. FIG. 4 shows an XRD test result of the porous magnetic microspheres. As shown in FIG. 3, the porous magnetic microspheres of the present embodiment have an average particle size of 650 m and a porosity of up to 82%. As shown in FIG. 4, the crystalline phases of the porous magnetic microspheres are mainly photocatalyst P-25 and magnetic Fe.sub.3O.sub.4.

APPLICATION EXAMPLE 1

[0043] The Fe-doped titanium dioxide photocatalytic porous magnetic microspheres of the present embodiment are used for catalytic degradation of an organic dye which is a methylene blue dye. The test method of photocatalytic performance is as follows. Methylene blue solution(100 mL, 50 mg/L) was placed in a beaker. The porous microspheres (50 mg) of the present embodiment was added to the beaker under stirring in a reactor box for 30 minutes without turning on a mercury lamp to achieve an adsorption-desorption equilibrium. Then the mercury lamp (500 W) source was turned on to irradiate the solution. A supernatant was extracted after centrifuging in a sampling interval time of 10 minutes. An absorbance of the methylene blue solution at 664 nm (maximum absorption wavelength) after photocatalytic reaction was measured by an ultraviolet-visible spectrophotometer. Finally, concentrations of the methylene blue solution at each time point were calculated according to the obtained data. The used photocatalyst was re-collected and used to perform the test of the photocatalytic performance again after being dried. The test of the photocatalytic performance was repeated 6 times to obtain the degradation data.

[0044] FIG. 5 is a graph showing a degradation rate versus time of the large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres of the present embodiment when it is used for catalytic degradation of a methylene blue dye for the first time. As shown in the test result of the photocatalytic performance in FIG. 5, the photocatalytic degradation rate of the methylene blue dye is up to 93.1% when it is degraded by the porous magnetic microspheres of the present embodiment 1 for 40 minutes.

[0045] The large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres of the present embodiment are used for repeatedly catalytic degradation of methylene blue dye for 6 times. A diagram showing comparative degradation rates of 6 cycles of catalytic degradation in a degradation time of 30 minutes is shown in FIG. 6. As shown in the test data of the degradation performance after repeated use in FIG. 6, the catalytic performance of the porous magnetic microspheres does not change significantly in 6 cycles of catalytic degradation.

EXAMPLE 2

[0046] In the present embodiment, a method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres includes the following steps.

[0047] (1) carboxymethylcellulose (0.5 g) was dissolved in 100 mL of distilled water to obtain a solution A with a concentration of 1.5 wt %.

[0048] (2) lanthanum potassium titanate (K.sub.2La.sub.2Ti.sub.3O.sub.10, 65 g, 0.1 mol, molecular weight: 659.5) photocatalyst was added to the solution A, and uniformly mixing under stirring to obtain a suspension B with a solid content of 65 wt %.

[0049] (3) saturated FeCl.sub.3 solution (8 mL, concentration: 92 g/100 mL) was uniformly mixed with the suspension B in step (2) under stirring to obtain a suspension C. The molar ratio of the Fe.sup.3+ ions and the lanthanum potassium titanate was 45:100.

[0050] (4) The suspension C was dropwise added to a saturated urea solution by a syringe equipped with a No. 4-sized needle to form microspheres. The microspheres were aged for 90 minutes and dried at 60 C.

[0051] (5) The microspheres dried in step (4) were calcined at 1100 C. for 90 minutes to obtain Fe-doped lanthanum potassium titanate photocatalytic porous magnetic microspheres.

[0052] The porous magnetic microspheres of the present embodiment are used for test. The test results show that the porous magnetic microspheres of the present embodiment have an average particle size of 430 m and a porosity of up to 75%.

[0053] The photocatalytic performance test is carried out by the same test method as in the application example 1. The results show that the degradation rate of the Fe-doped lanthanum potassium titanate photocatalytic porous magnetic microspheres of the present embodiment is up to 94.6% when it is used for catalytic degradation of methylene blue dye for 40 minutes for the first time. The catalytic performance of the porous magnetic microspheres does not change significantly in 6 cycles of catalytic degradation.

EXAMPLE 3

[0054] In the present embodiment, a method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres includes the following steps.

[0055] (1) Guar gum (0.5 g) was dissolved in 100 mL of distilled water to obtain a solution A with a concentration of 0.5 wt %.

[0056] (2) Strontium titanate (SrTiO.sub.3, 65 g, 0.354 mol, molecular weight: 183.46) photocatalyst was added to the solution A, and uniformly mixing under stirring to obtain a suspension B with a solid content of 65 wt %.

[0057] (3) Saturated Fe(NO.sub.3).sub.3 solution (9.5 mL, 138 g/100 mL) was uniformly mixed with the suspension B in step (2) under stirring to obtain a suspension C. The molar ratio of the Fe.sup.3+ ions and the strontium titanate was 15:100.

[0058] (4) The suspension C was dropwise added to a concentrated ammonia water by a syringe equipped with a No. 6-sized needle to form microspheres. The microspheres were aged for 120 minutes and were dried at 60 C.

[0059] (5) The microspheres dried in step (4) were calcined at 1000 C. for 120 minutes to obtain the Fe-doped strontium titanate photocatalytic porous magnetic microspheres.

[0060] The porous magnetic microspheres of the present embodiment are used for test. The test results show that the porous magnetic microspheres have an average particle size of 680 m and a porosity of up to 76%.

[0061] The photocatalytic performance test is carried out by the same test method as in the application example 1. The results show that the degradation rate of the Fe-doped strontium titanate photocatalytic porous magnetic microspheres of the present embodiment is up to 92.8% when it is used for catalytic degradation of methylene blue dye for 40 minutes for the first time. The catalytic performance of the sample did not change significantly in 6 cycles of catalytic degradation.

EXAMPLE 4

[0062] In the present embodiment, a method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres includes the following steps.

[0063] (1) Guar gum(1.0 g) was dissolved in 100 mL of distilled water to obtain a solution A with a concentration of 1.0 wt %.

[0064] (2) Zinc oxide (ZnO, 50 g, 0.973 mol, molecular weight: 81.38) photocatalyst was added to the solution A, and uniformly mixing under stirring to obtain a suspension B with a solid content of 50 wt %.

[0065] (3) saturated Fe(NO.sub.3).sub.3 solution (34 mL, 138 g/100 mL) was uniformly mixed with the suspension B in step (2) under stirring to obtain a suspension C. The molar ratio of the Fe.sup.3+ ions and the zinc oxide was 20:100.

[0066] (4) The suspension C was dropwise added to a concentrated ammonia water by a syringe equipped with a No. 4-sized needle to form microspheres. The microspheres were aged for 30 minutes and dried at 80 C.

[0067] (5) The microspheres dried in step (4) were calcined at 1050 C. for 90 minutes to obtain the Fe-doped zinc oxide photocatalytic porous magnetic microspheres.

[0068] The porous magnetic microspheres of the present embodiment are used for test. The test results show that the magnetic porous microspheres of the present embodiment have an average particle size of 480 m and a porosity of up to 84%.

[0069] The photocatalytic performance test is carried out by the same test method as in the application example 1. The results show that the degradation rate of the Fe-doped zinc oxide photocatalytic porous magnetic microspheres of the present embodiment is up to 89.6% when it is used for catalytic degradation of methylene blue dye for 40 minutes for the first time. The catalytic performance of the sample did not change significantly in 6 cycles of catalytic degradation.

EXAMPLE 5

[0070] In the present embodiment, a method of preparing large-size high-porosity Fe-doped photocatalytic porous magnetic microspheres includes the following steps.

[0071] (1) sesbania powder (1.2 g) was dissolved in 100 mL of distilled water to obtain a solution A with a concentration of 1.2 wt %.

[0072] (2) titanium dioxide (TiO.sub.2, 40 g, 0.5 mol, molecular weight: 79.87) photocatalyst (abbreviated as P25 below) was added to the solution A, and uniformly mixing under stirring to obtain a suspension B with a solid content of 40 wt %.

[0073] (3) saturated FeCl.sub.3 solution (26.5 mL, concentration: 92 g/100 ml) was uniformly mixed with the suspension B in the step (2) under stirring to obtain a suspension C. The molar ratio of the Fe.sup.3+ ions and the titanium dioxide was 30:100.

[0074] (4) The suspension C was dropwise added to a saturated hexamethylenetetramine solution by a syringe equipped with a No. 4-sized needle to form microspheres. The microspheres were aged for 60 minutes and dried at 70 C.

[0075] (5) The microspheres dried in the step (4) were calcined at 600 C. for 120 minutes to obtain Fe-doped titanium dioxide photocatalytic porous magnetic microspheres.

[0076] The porous magnetic microspheres of the present embodiment are used for test. The test results show that the porous magnetic microspheres of the present embodiment have an average particle size of 540 m and a porosity of up to 81%.

[0077] The photocatalytic performance test is carried out by the same test method as in the embodiment application 1. The results show that the degradation rate of the Fe-doped titanium dioxide photocatalytic porous magnetic microspheres of the present embodiment is up to 90.9% when it is used for catalytic degradation of methylene blue dye in 40 minutes for the first time. The catalytic performance of the sample does not change significantly in 6 cycles of catalytic degradation.