TWO-DIMENSIONAL CLAY BASED COMPOSITE PHOSPHORUS REMOVING AGENT AND PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The present invention belongs to the field of material preparation, and particularly relates to a two-dimensional clay based composite phosphorus removing agent and a preparation method. The two-dimensional clay based composite phosphorus removing agent provided by the present invention takes two-dimensional clay, hydroxide (such as lanthanum hydroxide, calcium hydroxide, magnesium hydroxide and aluminum hydroxide) and urea as raw materials, and the composite phosphorus removing agent with high property is prepared by a roasting method. Through a combined physical and chemical method, phosphorus in the phosphorus-containing wastewater is effectively removed by the synergic interaction between components of the composite phosphorus removing agent. The invention overcomes the defects of large consumption and secondary pollution easily caused by using metal hydroxides, metal oxides and metal salts separately as chemical phosphorus removing agents, and simultaneously expands the application fields of the two-dimensional clay.

Claims

1. A two-dimensional clay based composite phosphorus removing agent, comprising: two-dimensional clay; and oxide of M metal composited on a surface of the two-dimensional clay in situ; wherein the M metal is a metal capable of forming insoluble precipitate with phosphate.

2. The two-dimensional clay based composite phosphorus removing agent according to claim 1, wherein the two-dimensional clay is at least one of kaolinite, montmorillonite and rectorite.

3. The two-dimensional clay based composite phosphorus removing agent according to claim 1, wherein the M metal is at least one of calcium, magnesium, lanthanum and aluminum.

4. The two-dimensional clay based composite phosphorus removing agent according to claim 1, wherein a content of the oxide of the M metal is 15-50%.

5. The two-dimensional clay based composite phosphorus removing agent according to claim 2, wherein a content of the oxide of the M metal is 15-50%.

6. The two-dimensional clay based composite phosphorus removing agent according to claim 3, wherein a content of the oxide of the M metal is 15-50%.

7. A preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 1, wherein the two-dimensional clay based composite phosphorus removing agent is obtained by roasting mixed raw materials comprising the two-dimensional clay, hydroxide of the M metal and urea.

8. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 7, wherein the hydroxide of the M metal is at least one of calcium hydroxide, magnesium hydroxide, lanthanum hydroxide and aluminum hydroxide.

9. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 7, wherein a weight ratio of the two-dimensional clay powder to the hydroxide of the M metal is 1:0.2-3.

10. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 9, wherein the weight ratio of the two-dimensional clay powder to the hydroxide of the M metal is 1:1-3.

11. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 7, wherein a weight ratio of a mixture of the two-dimensional clay and the hydroxide of the M metal to the urea is 1:2.5-20.

12. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 11, wherein the weight ratio of a mixture of the two-dimensional clay and the hydroxide of the M metal to the urea is 1:5-20.

13. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 7, wherein a roasting process is performed under an oxygen-containing atmosphere.

14. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 7, wherein roasting temperature of the roasting process is not lower than temperature at which the hydroxide of the M metal is converted into corresponding oxide.

15. The preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 14, wherein the roasting temperature is 400-600 C., and roasting time is 1-5 h.

16. A preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 2, wherein the two-dimensional clay based composite phosphorus removing agent is obtained by roasting mixed raw materials comprising the two-dimensional clay, hydroxide of the M metal and urea.

17. A preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 3, wherein the two-dimensional clay based composite phosphorus removing agent is obtained by roasting mixed raw materials comprising the two-dimensional clay, hydroxide of the M metal and urea.

18. A preparation method of the two-dimensional clay based composite phosphorus removing agent according to claim 4, wherein the two-dimensional clay based composite phosphorus removing agent is obtained by roasting mixed raw materials comprising the two-dimensional clay, hydroxide of the M metal and urea.

19. A method for adsorption of phosphorus-containing wastewater, comprising using the two-dimensional clay based composite phosphorus removing agent according to claim 1.

20. A method for adsorption of phosphorus-containing wastewater, comprising using the two-dimensional clay based composite phosphorus removing agent prepared according to the preparation method of claim 5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG. 1 is an X-ray diffraction diagram of raw materials and a prepared rectorite based composite phosphorus removing agent before and after phosphorus adsorption according to Embodiment 1 of the present invention.

[0060] FIGS. 2a to 2d are scanning electron micrographs of the raw materials and the prepared rectorite based composite phosphorus removing agent before and after phosphorus adsorption according to Embodiment 1 of the present invention.

[0061] FIGS. 3a to 3d are transmission electron micrographs of the raw materials and the prepared rectorite based composite phosphorus removing agent before and after phosphorus adsorption according to Embodiment 1 of the present invention.

[0062] FIG. 4 is a phosphorus removal property comparison result of the raw materials and the corresponding composite phosphorus removing agent according to Embodiment 1 of the present invention. R: rectorite; L: lanthanum hydroxide; CR: a roasted product of rectorite; CL: a roasted product of lanthanum hydroxide; CLR: a mixed roasted product of rectorite and lanthanum hydroxide; CRU: a mixed roasted product of rectorite and urea; CLU: a mixed roasted product of lanthanum hydroxide and urea; and CLRU: a rectorite based composite phosphorus removing agent.

DESCRIPTION OF THE EMBODIMENTS

[0063] The present invention provides a two-dimensional clay based composite phosphorus removing agent and a preparation method. The preparation method includes the specific preparation steps that:

[0064] (1) two-dimensional clay is crushed to be 45 m or below through an ultrafine grinder to prepare two-dimensional clay powder for standby;

[0065] (2) 1 part of the two-dimensional clay powder and 0.2-3 parts of hydroxide of M metal (lanthanum hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide and the like) are mixed and uniformly ground;

[0066] (3) 5-20 parts of urea are added into the mixture of step (2), and the mixture is uniformly ground to obtain a ternary mixture; and

[0067] (4) the ternary mixture obtained in step (3) is put into a muffle furnace, and roasting and heat preservation are performed for 1-5 h under the temperature of 400-600 C. (a temperature rise rate is 3-10 C./min) to prepare the two-dimensional clay based composite phosphorus removing agent.

[0068] The present invention is further illustrated in combination with the following embodiments.

[0069] The block-shaped two-dimensional clay (rectorite, kaolinite and montmorillonite) is crushed to be 45 m or below through the ultrafine grinder to prepare the two-dimensional clay powder used for the following embodiments.

Embodiment 1

[0070] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0071] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0072] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

[0073] Detection Tests:

[0074] 1. The raw materials and the rectorite based composite phosphorus removing agent before and after phosphorus adsorption in Embodiment 1 are taken for wide-angle X-ray diffraction analysis, the result is shown in FIG. 1, lanthanum oxide is composited in situ in a roasting process, and the structure of the rectorite is not destroyed. The rectorite based composite phosphorus removing agent changes obviously in a phosphorus adsorption process.

[0075] 2. The raw materials and the rectorite based composite phosphorus removing agent before and after phosphorus adsorption in Embodiment 1 are taken for SEM analysis, and the result is shown in FIGS. 2a to 2d. FIG. 2a is an SEM graph of rectorite, FIG. 2b is an SEM graph of lanthanum hydroxide, FIG. 2c is an SEM graph of the rectorite based composite phosphorus removing agent before adsorption, and FIG. 2d is an SEM graph of the rectorite based composite phosphorus removing agent after adsorption. From the graphs, it can be seen that the rectorite is of a stacked compact layered structure, and the edge of the layered structure is curl; the lanthanum hydroxide is granular and agglomerated; the rectorite in the rectorite based composite phosphorus removing agent reserves the layered structure, lanthanum compound particles become smaller and are dispersed uniformly, the lanthanum oxide is composited on the surface of the rectorite in situ, and such morphology feature is beneficial to improving the phosphorus removal property of the rectorite based composite phosphorus removing agent; and after phosphorus adsorption, the phosphorus exists on the surface of the rectorite based composite phosphorus removing agent.

[0076] 3. The raw materials and the rectorite based composite phosphorus removing agent before and after phosphorus adsorption in Embodiment 1 are taken for TEM analysis, and the result is shown in FIGS. 3a to 3d. FIG. 3a is a TEM graph of rectorite, FIG. 3b is a TEM graph of lanthanum hydroxide, FIG. 3c is a TEM graph of the rectorite based composite phosphorus removing agent before adsorption, and FIG. 3d is a TEM graph of the rectorite based composite phosphorus removing agent after adsorption. From the graphs, it can be seen that the rectorite structure is layered and the lanthanum hydroxide is agglomerated; and the rectorite in the rectorite based composite phosphorus removing agent prepared by a roasting method reserves the layered structure, the lanthanum oxide is composited on the surface of the rectorite in a scale-like shape, and the morphology of the lanthanum oxide after phosphorus adsorption of the rectorite based composite phosphorus removing agent changes into a strip shape.

[0077] 4. FIG. 4 is a phosphorus removal property comparison result of rectorite, lanthanum hydroxide, a roasted product of rectorite, a roasted product of lanthanum hydroxide, a mixed roasted product of rectorite and lanthanum hydroxide, a mixed roasted product of rectorite and urea, a mixed roasted product of lanthanum hydroxide and urea and a rectorite based composite phosphorus removing agent under the conditions with TP concentration of 50 mg/L, sewage volume of 50 mL and dosage of 1 g/L when the preparation process is the same as that of Embodiment 1. As shown in FIG. 4, under the same conditions, the phosphorus removal effect of the rectorite based composite phosphorus removing agent is obviously higher than the phosphorus removal effect of rectorite and lanthanum hydroxide used separately, indicating that components of the rectorite based composite phosphorus removing agent have a synergic phosphorus removal function. The phosphorus removal effect of a composite phosphorus removing agent without rectorite is lower than that of the composite phosphorus removing agent with the rectorite, indicating that the rectorite is indispensable in the preparation process of the composite phosphorus removing agent.

Embodiment 2

[0078] (1) 0.1 g of rectorite powder and 0.1 g of calcium hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the calcium hydroxide;

[0079] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the calcium hydroxide and the urea; and

[0080] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 3

[0081] (1) 0.1 g of rectorite powder and 0.1 g of magnesium hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the magnesium hydroxide;

[0082] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground so obtain a ternary mixture of the rectorite, the magnesium hydroxide and the urea; and

[0083] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 4

[0084] (1) 0.1 g of rectorite powder and 0.1 g of aluminum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the aluminum hydroxide;

[0085] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the aluminum hydroxide and the urea; and

[0086] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 5

[0087] (1) 0.3 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0088] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0089] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 6

[0090] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0091] (2) 4 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground so obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0092] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 7

[0093] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0094] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0095] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 550 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 8

[0096] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0097] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0098] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 5 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 9

[0099] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide;

[0100] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum hydroxide and the urea; and

[0101] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 10 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Embodiment 10

[0102] (1) 0.1 g of kaolinite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the kaolinite and the lanthanum hydroxide;

[0103] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the kaolinite, the lanthanum hydroxide and the urea; and

[0104] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a kaolinite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the kaolinite based composite phosphorus removing agent is shown in Table 1.

Embodiment 11

[0105] (1) 0.1 g of montmorillonite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the montmorillonite and the lanthanum hydroxide;

[0106] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the montmorillonite, the lanthanum hydroxide and the urea; and

[0107] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a montmorillonite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the montmorillonite based composite phosphorus removing agent is shown in Table 1.

Comparative Example 1

[0108] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum carbonate are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum carbonate;

[0109] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the rectorite, the lanthanum carbonate and the urea; and

[0110] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Comparative Example 2

[0111] (1) 0.1 g of tubular halloysite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the tubular halloysite and the lanthanum hydroxide;

[0112] (2) 1 g of urea is weighed and added into the mixture obtained in step (1), and the mixture is uniformly ground to obtain a ternary mixture of the tubular halloysite, the lanthanum hydroxide and the urea; and

[0113] (3) the ternary mixture obtained in step (2) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a tubular halloysite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the tubular halloysite based composite phosphorus removing agent is shown in Table 1.

Comparative Example 3

[0114] (1) 0.1 g of rectorite powder and 0.1 g of lanthanum hydroxide are weighed, mixed and uniformly ground to obtain a mixture of the rectorite and the lanthanum hydroxide; and

[0115] (2) the mixture obtained in step (1) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a rectorite based composite phosphorus removing agent is prepared, and the phosphorus removal property of the rectorite based composite phosphorus removing agent is shown in Table 1.

Comparative Example 4

[0116] (1) 0.1 g of lanthanum hydroxide and 1 g of urea are weighed, mixed and uniformly ground to obtain a mixture of the lanthanum hydroxide and the urea; and

[0117] (2) the mixture obtained in step (1) is put into a muffle furnace (air atmosphere), and roasting and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), so that a composite phosphorus removing agent is prepared, and the phosphorus removal property of the composite phosphorus removing agent is shown in Table 1.

Comparative Example 5

[0118] An ex-situ compositing comparative example includes the specific operations as follows:

[0119] (1) 0.1 g of lanthanum hydroxide and 1 g of urea are weighed, mixed and uniformly ground to obtain a mixture of the lanthanum hydroxide and the urea;

[0120] (2) the mixture obtained in step (1) is put into a muffle furnace (air atmosphere), calcining and heat preservation are performed for 3 h under the temperature of 450 C. (a temperature rise rate is 5 C./min), and a calcined product is standby; and

[0121] (3) the calcined product obtained in step (2) and 0.1 g of rectorite are ball-milled and mixed, so that a composite phosphorus removing agent is prepared, and the phosphorus removal property of the composite phosphorus removing agent is shown in Table 1.

TABLE-US-00001 TABLE 1 Phosphorus Removal Property of Two-dimensional Clay Based Composite Phosphorus Removing Agents of All Embodiments and Materials of Comparative Examples TP Con- TP Con- Phos- centration centration phorus Sewage Before After Removal Volume Adsorption Adsorption Dosage Rate Embodiment (mL) (mg/L) (mg/L) (g/L) (%) Embodiment 50 100 0.01 4 99.99 1 Embodiment 50 100 0.03 6 99.97 2 Embodiment 50 100 0.65 6 99.35 3 Embodiment 50 100 0.57 6 99.43 4 Embodiment 50 100 1.42 8 98.58 5 Embodiment 50 100 0.78 4 99.22 6 Embodiment 50 100 0.06 4 99.94 7 Embodiment 50 100 0.01 4 99.99 8 Embodiment 50 100 0.35 4 99.65 9 Embodiment 50 100 0.01 4 99.99 10 Embodiment 50 100 0.01 4 99.99 11 Comparative 50 100 18.41 4 81.59 Example 1 Comparative 50 100 14.51 4 85.49 Example 2 Comparative 50 100 29.19 4 70.81 Example 3 Comparative 50 100 28.68 4 71.32 Example 4 Comparative 50 100 38.82 4 61.18 Example 5

[0122] From Table 1, it can be seen that by adoption of in-situ roasting of the two-dimensional clay, the metal hydroxide and the urea, the composite material with the metal oxide composited on the two-dimensional material in situ is obtained, and the material with the good phosphorus removal property can be prepared. When replacing the metal hydroxide with carbonate, replacing the two-dimensional clay with one-dimensional clay, not adding the urea or the like, the foregoing material cannot be obtained and the phosphorus removal property of the foregoing material is obviously affected.