Solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil and method for preparing same

Abstract

A solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil and a method for preparing the same. A hollow alumina ball prepared by 3D printing is taken as a solid heat carrier, copper-nickel-vanadium composite oxide is taken as a catalytic active component, and vinyltriethoxysilane is taken as a masking agent. The ball has a diameter of 30 mm to 60 mm and a thickness of 1 mm to 2 mm. An outer surface of the ball is masked with the vinyltriethoxysilane; then the ball is pierced to make an inner surface thereof connected with the outside through channels; the ball is then immersed in a catalytic active component precursor solution; and finally, drying and calcination are performed to obtain the solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil. This product is widely applicable to the field of thermal desorption of organic contaminants of soil.

Claims

1. A method for preparing a solid heat carrier catalyst comprising the following steps: (1) preparing a solid heat carrier by dissolving alumina powder, triethylene glycol diacrylate, and phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide in an organic solvent; performing stirring in a dark room to obtain a slurry; then printing the slurry with a ceramic 3D printer, and performing synchronous photo-curing by using a laser of the ceramic 3D printer, to obtain a hollow alumina ball; and after obtaining the hollow alumina ball, placing the hollow alumina ball in a muffle furnace for calcination to obtain the solid heat carrier; (2) preparing a pierced hollow alumina ball with the outer surface masked by placing the hollow alumina ball obtained in step (1) in vinyltriethoxysilane to immerse the hollow alumina ball therein, and then removing the hollow alumina ball from the vinyltriethoxysilane and placing the removed hollow alumina ball in a drying oven for drying to obtain a hollow alumina ball with the outer surface masked; then piercing the hollow alumina ball with the outer surface masked with a piercer to form at least two holes to make an inner surface thereof connected with the outside through channels to obtain a pierced hollow alumina ball with the outer surface masked; (3) preparing a catalytic active component precursor solution by weighing copper salt, nickel salt, vanadium salt and citric acid monohydrate, adding the same into deionized water and stirring in a water bath at 50 C. to 70 C. to obtain the catalytic active component precursor solution; and (4) preparing the solid heat carrier catalyst by immersing the pierced hollow alumina ball with the outer surface masked prepared in step (2) into the catalytic active component precursor solution prepared in step (3); after adsorption for 1 h to 3 h, placing the immersed pierced hollow alumina ball in a blast drying oven for heat-preservation drying; and then placing the dried pierced hollow alumina ball in a muffle furnace for calcination to obtain the solid heat carrier catalyst.

2. The method according to claim 1, wherein a mass ratio of the alumina powder to the triethylene glycol diacrylate to the phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide described in step (1) is (10 to 45):(10 to 54):(2 to 15).

3. The method according to claim 1, wherein a temperature of the calcination described in step (1) is 600 C. to 700 C., and the Calcination time is 2 h to 4 h.

4. The method according to claim 1, wherein a mass ratio of the hollow alumina ball to the vinyltriethoxysilane described in step (2) is 1:(0.1 to 1); the drying temperature described in step (2) is 35 C. to 50 C., and the drying time is 2 h to 4 h; and a hole diameter of the holes in the pierced hollow alumina ball with the outer surface masked is 3 to 8 mm.

5. The method according to claim 1, wherein the copper salt described in step (3) is copper nitrate or copper chloride dihydrate, the nickel salt is nickel nitrate hexahydrate or nickel chloride hexahydrate, and the vanadium salt is ammonium metavanadate.

6. The method according to claim 1, wherein the drying temperature described in step (4) is 80 C. to 100 C., and the drying time is 6 h to 10 h; and the calcination temperature in step (4) is 600 C. to 700 C., and the calcination time is 2 h to 4 h.

7. A method of decomposing an organic contaminant in soil, comprising contacting soil containing the organic contaminant with the solid heat carrier catalyst obtained in claim 1, wherein the organic contaminant is benzo[A]anthracene.

8. The method according to claim 1, wherein the organic solvent is ethylene glycol.

9. A solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil prepared according to the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a performance diagram of a catalyst prepared in Example 1;

(2) FIG. 2 is a performance diagram of a catalyst prepared in Example 2;

(3) FIG. 3 is a performance diagram of a catalyst prepared in Example 3;

(4) FIG. 4 is a performance diagram of a catalyst prepared in Example 4;

(5) FIG. 5 is a performance diagram of a catalyst prepared in Comparative Example 2;

(6) FIG. 6 is a performance diagram of a catalyst prepared in Comparative Example 3; and

(7) FIG. 7 is a performance diagram of a catalyst prepared in Comparative Example 4.

DETAILED DESCRIPTION

(8) The present invention is further described below in conjunction with embodiments, but the scope of protection of the present invention is not limited thereto: Example 1

(9) (1) Preparation of Solid Heat Carrier

(10) 10 g of alumina powder, 10 g of triethylene glycol diacrylate and 2 g of phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide were weighed and dissolved in 16 g of ethylene glycol. Stirring was performed in a dark room at 25 C. for 2 h to obtain slurry. Then the slurry was printed with a ceramic 3D printer. The printing rate was 5 cm.sup.2/h. Synchronous photo-curing was performed by using a laser of the ceramic 3D printer. The laser power was 5 W. After being obtained, the hollow alumina ball with a diameter of 30 mm and a thickness of 1 mm was placed in a muffle furnace for calcination at 600 C. for 4 h to obtain the solid heat carrier (the mass of the carrier was 5.47 g).

(11) (2) Masking of Outer Surface of Solid Heat Carrier

(12) The hollow alumina ball obtained in step (1) was placed in 1.094 g of vinyltriethoxysilane. The hollow alumina ball was immersed for 10 min. Then the immersed hollow alumina ball was taken out and placed in a drying oven for drying at 35 C. for 4 h. Then the hollow alumina ball with the outer surface masked was taken out. The hollow alumina ball was pierced with a piercer to form two circular holes (the hole diameter of 6 mm) to make the inner surface thereof connected with the outside through channels to obtain a pierced hollow alumina ball with the outer surface masked.

(13) (3) Preparation of Catalytic Active Component Precursor Solution

(14) Based on the mass of the carrier, the mass percentage content of the catalytic active component was 5%. A mass ratio of copper oxide to nickel oxide to vanadium oxide in the catalytic active component was 1:0.2:0.8. 0.3224 g of copper nitrate, 0.1064 g of nickel nitrate hexahydrate, 0.1407 g of ammonium metavanadate and 0.6448 g of citric acid monohydrate were weighed, and were added into 3.224 g of deionized water. Stirring was performed in a water bath at 50 C. until the solution appeared clear and transparent to obtain the active component precursor solution.

(15) (4) Preparation of Catalyst

(16) The pierced hollow alumina ball with the outer surface masked prepared in step (2) was immersed into the active component precursor ion solution prepared in step (3). After adsorption for 1 h, the immersed pierced hollow alumina ball was placed in a blast drying oven for heat-preservation drying at 80 C. for 10 h. Then the dried pierced hollow alumina ball was placed in a muffle furnace for calcination at 600 C. for 4 h to obtain the solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil.

(17) (5) Catalytic Activity Test

(18) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 25 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 31 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 20 mL/min. After thermal desorption at 180 C. for 10 min, the desorption effect of the benzo[A]anthracene could reach 100%.

Example 2

(19) (1) Preparation of Solid Heat Carrier

(20) 15 g of alumina powder, 24 g of triethylene glycol diacrylate and 6 g of phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide were weighed and dissolved in 24 g of ethylene glycol. Stirring was performed in a dark room at 35 C. for 1 h to obtain slurry. Then the slurry was printed with a ceramic 3D printer. The printing rate was 5 cm.sup.2/h. Synchronous photo-curing was performed by using a laser of the ceramic 3D printer. The laser power was 5 W. After being obtained, the hollow alumina ball with a diameter of 30 mm and a thickness of 2 mm was placed in a muffle furnace for calcination at 700 C. for 4 h to obtain the solid heat carrier (the mass of the carrier was 10.57 g).

(21) (2) Masking of Outer Surface of Solid Heat Carrier

(22) The hollow alumina ball obtained in step (1) was placed in 3.171 g of vinyltriethoxysilane. The hollow alumina ball was immersed for 10 min. Then the immersed hollow alumina ball was taken out and placed in a drying oven for drying at 50 C. for 2 h. Then the hollow alumina ball with the outer surface masked was taken out. The hollow alumina ball was pierced with a piercer to form two circular holes (the hole diameter of 6 mm) to make the inner surface thereof connected with the outside through channels to obtain a pierced hollow alumina ball with the outer surface masked.

(23) (3) Preparation of Catalytic Active Component Precursor Solution

(24) Based on the mass of the carrier, the mass percentage content of the catalytic active component was 10%. TA mass ratio of copper oxide to nickel oxide to vanadium oxide in the catalytic active component was 1:0.4:0.6. 1.1328 g of copper chloride dihydrate, 0.6726 g of nickel chloride hexahydrate, 0.4079 g of ammonium metavanadate and 3.3984 g of citric acid monohydrate were weighed, and were added into 11.328 g of deionized water. Stirring was performed in a water bath at 70 C. until the solution appeared clear and transparent to obtain the active component precursor solution.

(25) (4) Preparation of Catalyst

(26) The pierced hollow alumina ball with the outer surface masked prepared in step (2) was immersed into the active component precursor ion solution prepared in step (3). After adsorption for 3 h, the immersed pierced hollow alumina ball was placed in a blast drying oven for heat-preservation drying at 100 C. for 6 h. Then the dried pierced hollow alumina ball was placed in a muffle furnace for calcination at 700 C. for 2 h to obtain the solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil.

(27) (5) Catalytic Activity Test

(28) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 20 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 31 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 50 mL/min. After thermal desorption at 150 C. for 10 min, the desorption effect of the benzo[A]anthracene could reach 100%.

Example 3

(29) (1) Preparation of Solid Heat Carrier

(30) 25 g of alumina powder, 20 g of triethylene glycol diacrylate and 5 g of phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide were weighed and dissolved in 30 g of ethylene glycol. Stirring was performed in a dark room at 35 C. for 2 h to obtain slurry. Then the slurry was printed with a ceramic 3D printer. The printing rate was 5 cm.sup.2/h. Synchronous photo-curing was performed by using a laser of the ceramic 3D printer. The laser power was 5 W. After being obtained, the hollow alumina ball with a diameter of 60 mm and a thickness of 1 mm was placed in a muffle furnace for calcination at 700 C. for 2 h to obtain the solid heat carrier (the mass of the carrier was 22.24 g).

(31) (2) Masking of Outer Surface of Solid Heat Carrier

(32) The hollow alumina ball obtained in step (1) was placed in 4.448 g of vinyltriethoxysilane. The hollow alumina ball was immersed for 10 min. Then the immersed hollow alumina ball was taken out and placed in a drying oven for drying at 50 C. for 4 h. Then the hollow alumina ball with the outer surface masked was taken out. The hollow alumina ball was pierced with a piercer to form two circular holes (the hole diameter of 6 mm) to make the inner surface thereof connected with the outside through channels to obtain a pierced hollow alumina ball with the outer surface masked.

(33) (3) Preparation of Catalytic Active Component Precursor Solution

(34) Based on the mass of the carrier, the mass percentage content of the catalytic active component was 5%. A mass ratio of copper oxide to nickel oxide to vanadium oxide in the catalytic active component was 1:0.4:0.6. 1.1918 g of copper chloride dihydrate, 0.8656 g of nickel nitrate hexahydrate, 0.4291 g of ammonium metavanadate and 2.9795 g of citric acid monohydrate were weighed, and were added into 11.918 g of deionized water. Stirring was performed in a water bath at 60 C. until the solution appeared clear and transparent to obtain the active component precursor solution.

(35) (4) Preparation of Catalyst

(36) The pierced hollow alumina ball with the outer surface masked prepared in step (2) was immersed into the active component precursor ion solution prepared in step (3). After adsorption for 2 h, the immersed pierced hollow alumina ball was placed in a blast drying oven for heat-preservation drying at 90 C. for 8 h. Then the dried pierced hollow alumina ball was placed in a muffle furnace for calcination at 650 C. for 3 h to obtain the solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil.

(37) (5) Catalytic Activity Test

(38) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 200 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 61 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 30 mL/min. After thermal desorption at 180 C. for 20 min, the desorption effect of the benzo[A]anthracene could reach 100%.

Example 4

(39) (1) Preparation of Solid Heat Carrier

(40) 45 g of alumina powder, 54 g of triethylene glycol diacrylate and 15 g of phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide were weighed and dissolved in 90 g of ethylene glycol. Stirring was performed in a dark room at 35 C. for 2 h to obtain slurry. Then the slurry was printed with a ceramic 3D printer. The printing rate was 5 cm.sup.2/h. Synchronous photo-curing was performed by using a laser of the ceramic 3D printer. The laser power was 5 W. After being obtained, the hollow alumina ball with a diameter of 60 mm and a thickness of 2 mm was placed in a muffle furnace for calcination at 600 C. for 2 h to obtain the solid heat carrier (the mass of the carrier was 43.75 g).

(41) (2) Masking of Outer Surface of Solid Heat Carrier

(42) The hollow alumina ball obtained in step (1) was placed in 10.94 g of vinyltriethoxysilane. The hollow alumina ball was immersed for 10 min. Then the immersed hollow alumina ball was taken out and placed in a drying oven for drying at 50 C. for 4 h. Then the hollow alumina ball with the outer surface masked was taken out. The hollow alumina ball was pierced with a piercer to form two circular holes (the hole diameter of 6 mm) to make the inner surface thereof connected with the outside through channels to obtain a pierced hollow alumina ball with the outer surface masked.

(43) (3) Preparation of Catalytic Active Component Precursor Solution

(44) Based on the mass of the carrier, the mass percentage content of the catalytic active component was 10%. A mass ratio of copper oxide to nickel oxide to vanadium oxide in the catalytic active component was 1:0.2:0.8. 5.1578 g of copper nitrate, 1.7028 g of nickel nitrate hexahydrate, 2.2511 g of ammonium metavanadate and 10.3156 g of citric acid monohydrate were weighed, and were added into 51.578 g of deionized water. Stirring was performed in a water bath at 60 C. until the solution appeared clear and transparent to obtain the active component precursor solution.

(45) (4) Preparation of Catalyst

(46) The pierced hollow alumina ball with the outer surface masked prepared in step (2) was immersed into the active component precursor ion solution prepared in step (3). After adsorption for 2 h, the immersed pierced hollow alumina ball was placed in a blast drying oven for heat-preservation drying at 90 C. for 8 h. Then the dried pierced hollow alumina ball was placed in a muffle furnace for calcination at 650 C. for 3 h to obtain the solid heat carrier catalyst for thermal desorption of organic matter-contaminated soil.

(47) (5) Catalytic Activity Test

(48) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 200 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 61 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 30 mL/min. After thermal desorption at 150 C. for 20 min, the desorption effect of the benzo[A]anthracene could reach 100%.

Comparative Example 1

(49) (1) Preparation of Catalyst

(50) Except that the phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide was not used as a photoinitiator during the preparation of the catalyst, other conditions were the same as those in Example 1.

(51) (2) Comparison Effect

(52) Compared with those in Example 1, the phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide was not used as the photoinitiator during the preparation of the catalyst, and a 3D printed hollow alumina ball could not be formed.

Comparative Example 2

(53) (1) Preparation of Catalyst

(54) Except that the vinyltriethoxysilane was not used as the outer surface masking agent during the preparation of the catalyst, other conditions were the same as those in Example 2.

(55) (2) Catalytic Activity Test

(56) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 20 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 31 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 50 mL/min. After thermal desorption at 150 C. for 10 min, the desorption effect of the benzo[A]anthracene could reach 32.8%, and after thermal desorption at 210 C. for 20 min, the desorption effect of the benzo[A]anthracene could reach 100%.

(57) (3) Comparison Effect

(58) Compared with those in Example 2, the vinyltriethoxysilane was not used as the outer surface masking agent during the preparation of the catalyst, and at the same time, the active components were loaded on inner and outer surfaces of the hollow ball, while active sites on the outer surface could not contact the organic contaminant in the soil, thereby resulting in a significant decline in catalytic activity.

Comparative Example 3

(59) (1) Preparation of Catalyst

(60) Except that the copper chloride dihydrate was not added during the preparation of the catalyst, other conditions are the same as those in Example 3.

(61) (2) Catalytic Activity Test

(62) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 200 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 61 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 30 mL/min. After thermal desorption at 180 C. for 20 min, the desorption effect of the benzo[A]anthracene reached 34%.

(63) (3) Comparison Effect

(64) Compared with those in Example 3, the copper chloride dihydrate was not used during the preparation of the catalyst, and the active component lacked copper oxide with high oxidability, thereby resulting in a significant decrease in catalytic activity.

Comparative Example 4

(65) (1) Preparation of Catalyst

(66) Except that the ammonium metavanadate was not added during the preparation of the catalyst, other conditions are the same as those in Example 4.

(67) (2) Catalytic Activity Test

(68) One hollow alumina ball catalyst loaded with the active component was used as the catalyst by usage amount. 200 g of soil containing 1% benzo[A]anthracene was loaded into the hollow ball catalyst. The hollow ball catalyst was placed in an evaluation reaction device for catalyst performance. The inner diameter of a quartz tube in the evaluation reaction device was 61 mm. The soil heating temperature was 150 C. to 210 C. The temperature of hot air introduced was 150 C. to 210 C. The flow rate of the hot air was 30 mL/min. After thermal desorption at 150 C. for 30 min, the desorption effect of the benzo[A]anthracene reached 49%.

(69) (3) Comparison Effect

(70) Compared with those in Example 4, the ammonium metavanadate was not used during the preparation of the catalyst, and the active component lacked vanadium pentoxide with excellent reducibility, thereby resulting in a significant decrease in catalytic activity.