Ozone catalyst as well as preparation method and application thereof

Abstract

The invention discloses an ozone catalyst and a preparation method and application thereof. According to the method for preparing the ozone catalyst provided by the invention, the ozone catalyst is prepared on the basis of resource utilization of the algae biomass and the heavy metal wastewater, the algae biomass is firstly used for adsorbing the heavy metal wastewater, and then the heavy metal wastewater is mixed with the carrier powder to prepare the granular ozone catalyst; according to the ozone catalyst, carbon fixed when algae cells absorb carbon dioxide can be used as a carbon catalysis substrate, nitrogen and phosphorus elements absorbed by the algae cells from wastewater and synthesized into cell components and functional group structures of the nitrogen and phosphorus elements are used for providing catalytic active sites, and meanwhile metal elements in heavy metal wastewater are fully utilized as catalytic active components; the catalyst has the excellent characteristics of high activity, low cost, easy recovery and stable performance.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to an ozone catalyst and a preparation method and application thereof. Background Art

[0002] In the field of wastewater treatment, in addition to improving and ensuring treatment efficiency, there is also a widespread demand for carbon reduction and resource recovery throughout the process. Ozone catalytic oxidation is one of the most widely used wastewater deep treatment technologies. As the core of this technology, the selection of key raw materials for ozone catalysts plays a vital role in the operating performance and cost of the process. Currently, commonly used ozone catalysts are mainly composed of a matrix (carrier) and an active component. The commonly used raw materials for the matrix (carrier) are alumina, zeolite, diatomaceous earth, etc.; the active components mainly come from metals or carbon materials, etc. In addition, the introduction of elements such as nitrogen and phosphorus is also conducive to the formation of high catalytic activity sites. With the continuous promotion of ozone catalytic oxidation technology, the demand for highly active, low-cost, and widely available catalyst preparation raw materials is increasing.

[0003] Metal-supported ozone catalysts are prepared by loading catalytically active metals onto aluminum-based or silicon-aluminum-based carriers, and inducing ozone to generate free radicals such as OH· to oxidize pollutants in wastewater. Metals commonly used to prepare ozone catalysts include copper, nickel, manganese, titanium, vanadium, etc. Metals are typical non-renewable resources. They are not only expensive, but also inevitably accompanied by large amounts of energy consumption and greenhouse gas emissions during mining and smelting processes. At the same time, my country's electroplating, mining, mechanical processing and manufacturing industries discharge a large amount of heavy metal wastewater every year. These heavy metal wastewaters are generally treated by chemical precipitation and other methods, and the resulting chemical sludge is disposed of as hazardous waste.

[0004] Algae are common autotrophic organisms in aquatic environments and play an important role as producers in aquatic ecosystems. Algae cells absorb nutrients such as nitrogen and phosphorus in water and carbon dioxide in the air to synthesize cell substances. They naturally have carbon, nitrogen, and phosphorus elements and a specific cell structure. Using algae biomass as a raw material for preparing ozone catalysts can directly introduce highly catalytically active carbon matrices and nitrogen and phosphorus active sites.

[0005] Algae biomass has the advantages of being easy to obtain and inexpensive. On the one hand, algae cultivation technology has been mature and stable, and there are engineering applications for large-scale algae cultivation using industrial flue gas; on the other hand, a large amount of algae biomass can be salvaged and collected from water bodies such as algal blooms and red tides. These algae biomass urgently need ways to be utilized as resources.

[0006] Powdered ozone catalysts are prepared by direct sintering of algae biomass. Although they have excellent catalytic effects, powdered catalysts are not easy to recycle and are difficult to apply in practical projects. Summary of the invention

[0007] The purpose of this application is to provide an ozone catalyst and its preparation method and application. To achieve the above invention purpose, the technical solution adopted in this application is:

[0008] In a first aspect, the present application provides a method for preparing an ozone catalyst, comprising the following steps:

[0009] (1) contacting the algae biomass with heavy metal wastewater, allowing it to stand for adsorption, and drying it to obtain a heavy metal-algae biomass dry product;

[0010] (2) mixing the heavy metal-algae biomass dry product with carrier powder, granulating, and obtaining intermediate product particles;

[0011] (3) drying the intermediate particles and calcining them in an inert atmosphere.

[0012] In an optional embodiment, in step (1), when the algae biomass is contacted with the heavy metal wastewater, the amount of the algae biomass is 0.5 to 2 g / L;

[0013] And / or, the heavy metal content in the heavy metal wastewater is 1-40 mg / L.

[0014] In an optional embodiment, in step (1), the static adsorption time is 0.5 to 24 hours.

[0015] In an optional embodiment, in step (1), the drying comprises: after the static adsorption is completed, collecting the naturally settled algae biomass, and dehydrating and drying it to a moisture content of no more than 5%.

[0016] In an optional embodiment, in step (2), when the heavy metal-algae biomass dry product is mixed with the carrier powder, the weight ratio of the heavy metal-algae biomass dry product to the carrier powder is 1:(8-20);

[0017] And / or, the carrier powder is dried at 105-120° C. and has a particle size of 200-1200 mesh;

[0018] And / or, the particle size of the intermediate particles is 3 to 4 mm.

[0019] Illustratively, in step (2), the granulation method may be ball granulation, and water or a diluted acetic acid solution may be sprayed appropriately during the granulation process according to the particle growth conditions.

[0020] In an optional embodiment, in step (3), the drying conditions include: a drying temperature of 60 to 80° C. and a drying time of not less than 12 h;

[0021] And / or, the calcination conditions include: a calcination temperature of 500-800° C., and a calcination time of not less than 3 hours; and the inactive atmosphere includes at least one of a nitrogen atmosphere, an argon atmosphere, or a vacuum atmosphere.

[0022] In an optional embodiment, the algae biomass includes algae organisms and / or algae residues; the algae includes at least one of cyanobacteria, green algae and diatoms;

[0023] And / or, the carrier powder includes aluminum-based carrier powder and / or silicon-aluminum-based carrier powder; the aluminum-based carrier powder includes alumina powder, and the silicon-aluminum-based carrier powder includes natural zeolite powder.

[0024] In a second aspect, the present application provides an ozone catalyst, which is prepared by the above method.

[0025] In a third aspect, the present application provides the use of the above-mentioned ozone catalyst in wastewater treatment.

[0026] In a fourth aspect, the present application provides a product for wastewater treatment, wherein the product comprises the above-mentioned ozone catalyst.

[0027] The technical solution of this application has at least the following beneficial effects:

[0028] The method for preparing an ozone catalyst provided in the present application is based on the resource utilization of algae biomass and heavy metal wastewater to prepare an ozone catalyst. The heavy metal wastewater is first adsorbed by algae biomass, and then mixed with a carrier powder to prepare a granular ozone catalyst. The ozone catalyst can use the carbon fixed by the algae cells absorbing carbon dioxide as a carbon catalytic matrix, and use the nitrogen and phosphorus elements and their functional group structures absorbed from the wastewater and synthesized into the cell components by the algae cells to provide catalytic active sites, while making full use of the metal elements in the heavy metal wastewater as catalytic active components, and has the excellent characteristics of high activity, low cost, easy recovery and stable performance.

[0029] Specifically, in the method for preparing an ozone catalyst provided in the present application, a highly active carbon catalytic matrix and active catalytic sites of nitrogen and phosphorus atoms are introduced using algae biomass as a raw material to enhance the catalytic effect of the ozone catalyst; the algae biomass raw material used can come from water bloom algae, or from algae cultivated for flue gas carbon fixation, which is a good way to realize the resource utilization of solid waste; the algae cells fully adsorb heavy metals in the wastewater, which can simultaneously achieve the purification of the heavy metal wastewater quality and reduce the generation of hazardous waste under the traditional precipitation treatment method of heavy metal wastewater, and the heavy metal components are used as catalyst active components, thereby realizing the resource utilization of metal components; at the same time, cheap and readily available alumina powder, natural zeolite powder, etc. are used to realize the granulation of the catalyst form and stable recovery in application; the preparation method is novel and simple, easy to promote, and has good environmental and economic benefits. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and results taken by the present invention to achieve the predetermined invention purpose, the specific implementation methods, technical solutions and features of the present invention application are described in detail below with preferred embodiments. The specific features, structures, or characteristics of the multiple embodiments in the following description can be combined in any suitable form.

[0031] Example 1

[0032] The ozone catalyst was prepared as follows:

[0033] The raw materials of ozone catalysts include: bloom algae (mainly cyanobacteria, including green algae, Chlamydomonas, etc.), alumina powder, and electroplating copper-containing wastewater.

[0034] (1) The algae cells salvaged from the water body of the water bloom were transferred to the electroplating copper-containing wastewater. After mixing, the algae cell content was about 1g / L and the divalent copper content was about 10mg / L. After low-speed stirring to make it fully mixed, it was allowed to stand for adsorption for 24 hours, and the algae cells were used to adsorb heavy metals;

[0035] (2) After the static adsorption in step (1) is completed, the algae biomass that has settled spontaneously is collected and dehydrated and dried to reduce its moisture content to less than 5%, thereby obtaining a heavy metal-algae biomass dry product;

[0036] (3) drying the ground (200-1200 mesh) alumina powder at 105-120°C for later use;

[0037] (4) mixing the heavy metal-algae biomass dry product obtained in step (2) and the alumina powder obtained in step (3) in a weight ratio of 1:15, and granulating by rolling balls. During the granulation process, water is sprayed appropriately according to the growth of the particles until uniform particles with a particle size of 3 to 4 mm are formed, thereby obtaining intermediate particles;

[0038] (5) The intermediate particles prepared in step (4) were dried at 60° C. for 24 h, and then calcined at 500° C. in a vacuum atmosphere for 5 h to obtain an ozone catalyst.

[0039] Example 2

[0040] The ozone catalyst was prepared as follows:

[0041] The raw materials of ozone catalyst include: Chlorella, natural zeolite powder, and electroplating copper-nickel mixed wastewater.

[0042] (1) Chlorella algae cells are added to the copper-nickel electroplating mixed wastewater, after which the algae cell content is about 1.5 g / L, the divalent copper content is about 15 mg / L, and the divalent nickel content is about 2 mg / L. The mixture is stirred at a low speed to be fully mixed and then allowed to stand for adsorption for 24 hours, and the heavy metals are adsorbed by the algae cells;

[0043] (2) After the static adsorption in step (1) is completed, the self-precipitated Chlorella is collected and dehydrated and dried to reduce its moisture content to less than 5%, thereby obtaining a heavy metal-algae biomass dry product;

[0044] (3) drying the ground (200-1200 mesh) natural zeolite powder at 105-120° C. for later use;

[0045] (4) mixing the heavy metal-algae biomass dry product obtained in step (2) and the natural zeolite powder obtained in step (3) in a weight ratio of 1:10, and granulating by rolling. During the granulation process, a diluted acetic acid solution is appropriately sprayed according to the growth of the particles until uniform particles with a particle size of 3 to 4 mm are formed, thereby obtaining intermediate particles;

[0046] (5) The intermediate particles prepared in step (4) were dried at 80° C. for 12 h, and then calcined at 800° C. in a nitrogen atmosphere for 3 h to obtain an ozone catalyst.

[0047] Example 3

[0048] The ozone catalyst was prepared as follows:

[0049] The raw materials of ozone catalyst include: spirulina, alumina powder, and copper-manganese mining wastewater.

[0050] (1) Spirulina algae cells were added to copper-manganese mining wastewater. After mixing, the algae cell content was about 1 g / L, the divalent copper content was about 20 mg / L, and the divalent manganese content was about 5 mg / L. After low-speed stirring to fully mix, the mixture was allowed to stand for adsorption for 24 hours, and the algae cells were used to adsorb heavy metals.

[0051] (2) After the static adsorption in step (1) is completed, the spirulina that has settled spontaneously is collected and dehydrated and dried to reduce its moisture content to less than 5%, thereby obtaining a heavy metal-algae biomass dry product;

[0052] (3) drying the ground (200-1200 mesh) alumina powder at 105-120° C. for later use;

[0053] (4) mixing the heavy metal-algae biomass dry product obtained in step (2) and the alumina powder obtained in step (3) in a weight ratio of 1:12, and granulating by rolling balls. During the granulation process, water is sprayed appropriately according to the growth of the particles until uniform particles with a particle size of 3 to 4 mm are formed, thereby obtaining intermediate particles;

[0054] (5) The intermediate particles prepared in step (4) were dried at 80° C. for 20 h, and then calcined at 600° C. in an argon atmosphere for 3 h to obtain an ozone catalyst.

[0055] Comparative Example 1

[0056] Commercial ozone catalysts, with alumina as the support and metal as the active component, were purchased from Pingxiang City, Jiangxi Province, China.

[0057] Comparative Example 2

[0058] A metal-based ozone catalyst, the catalyst raw materials include: 94% aluminum oxide powder and 6% manganese oxide. The preparation method is as follows:

[0059] (1) Evenly mix the ground and dried catalyst carrier (alumina powder) and active component (manganese oxide);

[0060] (2) placing the mixture in a granulator for granulation, adding acetic acid of a certain volume concentration until uniform particles with a particle size of 3 to 4 mm are formed;

[0061] (3) The prepared particles were dried at 120° C. for 12 h, and then calcined at 500° C. in an air atmosphere for 3 h to obtain a metal-based ozone catalyst.

[0062] Comparative Example 3

[0063] The ozone catalyst was prepared as follows:

[0064] The raw materials of ozone catalyst include: bloom algae (mainly cyanobacteria, including green algae, Chlamydomonas, etc.) and alumina powder.

[0065] (1) dehydrating and drying the algae cells salvaged from the water body of the algae bloom to reduce the moisture content to below 5%, thereby obtaining a dried algae biomass product;

[0066] (2) drying the ground (200-1200 mesh) alumina powder at 105-120°C for later use;

[0067] (3) The dried algae biomass obtained in step (1) and the alumina powder obtained in step (2) are uniformly mixed in a weight ratio of 1:15, and granulated by rolling balls. During the granulation process, water is sprayed appropriately according to the growth of the particles until uniform particles with a particle size of 3 to 4 mm are formed, thereby obtaining intermediate particles;

[0068] (4) The intermediate particles prepared in step (3) were dried at 60° C. for 24 h, and then calcined at 500° C. in a vacuum atmosphere for 5 h to obtain an ozone catalyst.

[0069] Experimental example

[0070] The ozone catalysts obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were used to perform ozone catalytic oxidation deep treatment on a certain petrochemical wastewater (TOC concentration of 15.84 mg / L), and the treatment conditions were: ozone concentration of 3 mg / L, flow rate of 100 mL / min, oxidation time of 30 min, and influent TOC concentration of 15.84 mg / L. After the oxidation was completed, the TOC concentration of each treated effluent was detected, and the TOC removal rate was calculated. The results are shown in Table 1.

[0071] Table 1 TOC concentration and TOC removal rate of each treated effluent

[0072] Ozone catalyst Outlet TOC concentration, mg / L TOC removal rate, % Example 1 6.77 57.3 Example 2 7.12 55.1 Example 3 6.06 61.7 Comparative Example 1 10.46 34.0 Comparative Example 2 10.14 36.0 Comparative Example 3 7.45 53.0

[0073] As can be seen from Table 1, after treatment under the same conditions, compared with the raw water, the TOC removal rate of the effluent treated by the ozone catalyst of the present application is above 55%. The ozone catalysts of Comparative Examples 1 and 2 have a maximum TOC removal rate of 36% in raw water. It can be seen that the ozone catalyst based on the resource utilization of algae biomass and heavy metal wastewater in the present application has significantly improved performance in wastewater treatment compared with the comparative example, indicating that the ozone catalyst prepared by the method of the present application has good product activity and good effect in ozone catalytic oxidation.

[0074] The above is only a preferred specific implementation of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and its improved conception within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing an ozone catalyst, characterized in that: The steps include: (1) contacting the algae biomass with heavy metal wastewater, allowing it to stand for adsorption, and drying it to obtain a heavy metal-algae biomass dry product; (2) mixing the heavy metal-algae biomass dry product with carrier powder, granulating, and obtaining intermediate product particles; (3) drying the intermediate particles and calcining them in an inert atmosphere.

2. The method according to claim 1, characterized in that In step (1), when the algae biomass is contacted with the heavy metal wastewater, the amount of the algae biomass is 0.5 to 2 g / L; And / or, the heavy metal content in the heavy metal wastewater is 1-40 mg / L.

3. The method according to claim 1, characterized in that In step (1), the static adsorption time is 0.5 to 24 hours.

4. The method according to claim 1, characterized in that: In step (1), the drying comprises: after the static adsorption is completed, the naturally settled algae biomass is collected and dehydrated to a moisture content of no more than 5%.

5. The method according to claim 1, characterized in that In step (2), when the heavy metal-algae biomass dry product is mixed with the carrier powder, the weight ratio of the heavy metal-algae biomass dry product to the carrier powder is 1:(8-20); And / or, the carrier powder is dried at 105-120° C. and has a particle size of 200-1200 mesh; And / or, the particle size of the intermediate particles is 3 to 4 mm.

6. The method according to claim 1, characterized in that In step (3), the drying conditions include: a drying temperature of 60 to 80° C. and a drying time of not less than 12 h; And / or, the calcination conditions include: a calcination temperature of 500-800° C., and a calcination time of not less than 3 hours; and the inactive atmosphere includes at least one of a nitrogen atmosphere, an argon atmosphere, or a vacuum atmosphere.

7. The method according to any one of claims 1 to 6, characterized in that The algae biomass includes algae organisms and / or algae residues; the algae includes at least one of cyanobacteria, green algae and diatoms; And / or, the carrier powder includes aluminum-based carrier powder and / or silicon-aluminum-based carrier powder; the aluminum-based carrier powder includes aluminum oxide powder, and the silicon-aluminum-based carrier powder includes natural zeolite powder.

8. An ozone catalyst, characterized in that The ozone catalyst is prepared by the method according to any one of claims 1 to 7.

9. Use of the ozone catalyst according to claim 8 in wastewater treatment.

10. A product for wastewater treatment, characterized in that: The product comprises the ozone catalyst according to claim 8.