阅读说明：本技术 一种污泥炭基臭氧催化剂及其制备方法 (Sludge carbon-based ozone catalyst and preparation method thereof ) 是由 王长智 王睿 谭映宇 丁志农 钱洲 梅荣武 茅宏 于 2020-05-15 设计创作，主要内容包括：本发明公开了一种污泥炭基臭氧催化剂及其制备方法,所述制备方法包括步骤：(1)将粉末状的污泥炭、催化组分、造孔剂和粘合剂作为原料混合均匀,加水搅拌混合得到混合物料；(2)混合物料经螺旋挤出机进行挤出、造粒,然后抛光制成生料球；(3)生料球室温风干后,放入电热恒温鼓风干燥箱中烘干；(4)烘干的生料球在电阻炉中焙烧制成烧结型污泥炭基臭氧催化剂。本制备方法工艺路线简单、原料成本低、生产过程容易控制,制备的污泥炭基臭氧催化剂孔隙发达、机械强度高、使用寿命长。可用于印染、化工等工业废水深度处理,也可用于污水处理厂生化出水深度处理等领域。(The invention discloses a sludge carbon-based ozone catalyst and a preparation method thereof, wherein the preparation method comprises the following steps: (1) uniformly mixing powdered sewage peat, a catalytic component, a pore-forming agent and an adhesive as raw materials, adding water, stirring and mixing to obtain a mixed material; (2) extruding and granulating the mixed material by a screw extruder, and then polishing to prepare raw material balls; (3) drying the raw material balls at room temperature, and then drying the raw material balls in an electric heating constant-temperature blast drying oven; (4) and roasting the dried raw material balls in a resistance furnace to prepare the sintered sludge carbon-based ozone catalyst. The preparation method has the advantages of simple process route, low raw material cost, easy control of the production process, developed pores of the prepared sludge carbon-based ozone catalyst, high mechanical strength and long service life. Can be used for advanced treatment of industrial wastewater such as printing and dyeing, chemical engineering and the like, and can also be used in the fields of advanced treatment of biochemical effluent of sewage treatment plants and the like.)

1. The preparation method of the sludge carbon-based ozone catalyst is characterized by comprising the following steps of:

(1) uniformly mixing powdered sewage peat, a catalytic component, a pore-forming agent and an adhesive as raw materials, adding water, stirring and mixing to obtain a mixed material;

(2) extruding the mixed material by a screw extruder, granulating and polishing to prepare raw material balls;

(3) drying the raw material balls at room temperature, and then drying the raw material balls in an electric heating constant-temperature blast drying oven;

(4) and roasting the dried raw material balls in a resistance furnace to prepare the sintered sludge carbon-based ozone catalyst.

2. The method according to claim 1, wherein in step (1), the method for preparing the peat comprises: drying sludge of a sewage treatment plant by using waste heat until the water content is 20-30%, then heating the sludge to 650 ℃ in a pyrolysis furnace at the heating rate of 10 ℃/min for pyrolysis for 1h, cooling the sludge, crushing the cooled sludge by using a crusher, and sieving the crushed sludge with a 100-mesh sieve to obtain powdery sludge carbon;

the mass of the peat in the raw materials accounts for 45-55%.

3. The preparation method according to claim 1, wherein in the step (1), the catalytic component comprises any one or more of powdered iron, powdered copper, powdered magnetic, alumina, nickel oxide, manganese dioxide and manganese acetate, and the mass ratio of the catalytic component in the raw materials is 15-40%.

4. The preparation method according to claim 1, wherein in the step (1), the pore-forming agent is gas-generating powder or ammonium bicarbonate, and the mass ratio of the pore-forming agent in the raw materials is 0.5-9%.

5. The preparation method according to claim 1, wherein in the step (1), the binder is bentonite, and the mass ratio of the binder in the raw materials is 6-13%.

6. The preparation method according to claim 1, wherein in the step (2), the particle size of the raw meal ball is 6-8 mm.

7. The preparation method according to claim 1, wherein in the step (3), the drying temperature of the electric heating constant temperature air drying oven is set to be 100-120 ℃.

8. The preparation method according to claim 1, wherein in the step (4), the temperature of the resistance furnace is set to 1000 to 1200 ℃, the heating rate is 10 ℃/min, and the baking time is 0.5 to 1 hour.

9. The preparation method according to claim 8, wherein in the step (4), the temperature of the resistance furnace is raised to 600 ℃ and then kept for 1 hour, and then the temperature is raised continuously.

10. The sludge carbon-based ozone catalyst prepared by the preparation method according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a sludge carbon-based ozone catalyst and a preparation method thereof.

Background

In recent years, along with the increase of organic matters which are difficult to degrade in sewage, the sewage treatment is difficult to reach the standard and discharge by means of a biological method, and the market demand for further advanced treatment of biochemical effluent is increasingly urgent. The common advanced sewage treatment methods, such as coagulating sedimentation, adsorption, membrane filtration and the like, can realize separation and transfer of pollutants, but may bring new secondary pollution problems along with the generation of a large amount of sludge and the enrichment of pollutants with higher concentration. In contrast, the advanced oxidation method uses hydroxyl radicals as a main oxidant to oxidize macromolecular refractory organics into low-toxicity or non-toxic micromolecular substances, and can be divided into photochemical oxidation, catalytic wet oxidation, ozone oxidation, electrochemical oxidation, Fenton oxidation and the like according to the mode of generating the radicals and different reaction conditions. Because the advanced oxidation method can degrade most of macromolecular organic pollutants in the biochemical effluent, the soluble COD in the biochemical effluent is removed, and the application of the method in the upgrading and modifying project of a sewage treatment plant is more and more common. Among them, the ozone oxidation method is gradually and widely used due to its characteristics of high oxidation efficiency, simple process, no secondary pollution, etc. However, the independent use of ozone for advanced treatment of biochemical effluent has the limitations of strong selectivity and poor mineralization of pollutants, and the defects of low solubility and stability of ozone in water, and the like, so that the utilization rate of direct use of ozone for oxidation is low, and the operation cost is high. In order to enhance the effect of ozone oxidation, ozone utilization efficiency is generally improved by adding an ozone catalyst. Numerous researches show that the catalyst is added into an ozone system, so that the capability of the ozone system for generating hydroxyl radicals (OH) can be obviously improved, the thorough oxidation of organic matters is promoted, and the capability of ozone for directly oxidizing the organic matters is improved. According to different phases of the added catalyst, homogeneous ozone catalytic oxidation and heterogeneous ozone catalytic oxidation can be divided. Homogeneous ozone catalytic oxidation is based on metal ions which are uniformly distributed in a solution and are used as catalytic active components, the catalytic activity is high, trace catalytic active components need to be additionally separated after the homogeneous ozone catalytic oxidation is used, the catalyst is easy to lose in a water body in the using process to cause secondary pollution, and the practical value is low. The heterogeneous ozone catalytic oxidation uses a solid filler as a catalyst to achieve the purpose of removing pollutants through deep oxidation. Compared with homogeneous ozone catalytic oxidation, heterogeneous ozone catalytic oxidation has the advantages of simple catalyst preparation, easy recovery and treatment, no secondary pollution, low water treatment cost, high activity, long service life and the like, thereby having better prospect.

The common heterogeneous ozone catalyst is prepared by uniformly dispersing and loading metals with catalytic activity and metal oxides on the surface of a carrier by using a coprecipitation method, an impregnation method, an ion exchange method and the like by taking a porous adsorption medium as the carrier mostly, such as alumina, a molecular sieve, activated carbon and the like. However, the carrier material is generally expensive, which increases the preparation cost of the catalyst to some extent and limits the application range of the catalyst. The invention patent with application number 201910215093.2 discloses a Fenton sludge catalyst for catalytic oxidation of nbsCOD by ozone and a preparation and application method thereof, wherein the ozone catalyst is prepared by attaching sludge generated by Fenton reaction on the surface of rho-alumina, and because rho-alumina has higher proportion, the catalytic active components in Fenton sludge are less, and the catalytic oxidation effect and stability of ozone are not high. The invention patent with the application number of 201810179616.8 discloses a magnesium oxide-sludge carbon hollow sphere ozone catalyst with a porous surface and a preparation method and application thereof.

Sludge is a byproduct of wastewater treatment process, the volume of the sludge accounts for about 0.3-0.5% of the treated water amount, and if the wastewater is deeply treated, the sludge amount can be increased by 0.5-1 time. The wet sludge (with water content of 80%) of a town sewage treatment plant is produced by 4000 ten thousand tons every year in 2017, and the annual production is estimated to be 6000 ten thousand tons in 2020. The sludge contains a large amount of harmful substances including heavy metals, pathogenic microorganisms, refractory organic matters and the like, and the traditional sludge disposal modes (such as landfill, incineration, land utilization and the like) are easy to cause secondary pollution. Research shows that the sludge carbon produced by using the sludge has the physical and chemical characteristics of porosity, high specific surface area and the like, the heavy metal fixed in the sludge carbon has a certain catalytic action, and the ozone catalyst is prepared by mixing the sludge carbon serving as a raw material with other metal powder, granulating and sintering the mixture, so that a high-valued way can be provided for the resource utilization of the sludge, and the production cost of the ozone catalyst can be reduced. The sludge carbon-based ozone catalyst is suitable for advanced treatment of biochemical effluent of a sewage treatment plant to remove COD (chemical oxygen demand), and pretreatment of industrial wastewater such as printing and dyeing, papermaking, chemical industry and the like to improve the biodegradability of the wastewater, and has the advantages of high treatment efficiency, simple operation and low comprehensive cost.

Disclosure of Invention

Aiming at the problems of defects and high production cost in the preparation process of the sintered ozone catalyst, the invention provides the preparation method of the sludge carbon-based ozone catalyst, which utilizes sludge carbon to prepare the sintered sludge carbon-based ozone catalyst, realizes resource utilization of sludge and is beneficial to reducing the cost of ozone catalytic oxidation treatment of biochemical effluent.

A preparation method of a sludge carbon-based ozone catalyst comprises the following steps:

(1) uniformly mixing powdered sewage peat, a catalytic component, a pore-forming agent and an adhesive as raw materials, adding water, stirring and mixing to obtain a mixed material;

(2) extruding the mixed material by a screw extruder, granulating and polishing to prepare raw material balls;

(3) drying the raw material balls at room temperature, and then drying the raw material balls in an electric heating constant-temperature blast drying oven;

(4) and roasting the dried raw material balls in a resistance furnace to prepare the sintered sludge carbon-based ozone catalyst.

Preferably, in step (1), the preparation method of the peat comprises: drying sludge of a sewage treatment plant by using waste heat until the water content is 20-30%, then heating the sludge to 650 ℃ in a pyrolysis furnace at the heating rate of 10 ℃/min for pyrolysis for 1h, cooling the sludge, crushing the cooled sludge by using a crusher, and sieving the crushed sludge by using a 100-mesh sieve to obtain powdery sludge.

Preferably, the mass of the peat in the raw material accounts for 45-55%.

Preferably, in the step (1), the catalytic component includes one or more of iron powder, copper powder, magnetic powder, aluminum oxide, nickel oxide, manganese dioxide and manganese acetate.

Preferably, the mass ratio of the catalytic component in the raw material is 15-40%.

Preferably, in the step (1), the pore-forming agent is gas-generating powder or ammonium bicarbonate.

Preferably, the pore-forming agent accounts for 0.5 to 9% by mass of the raw material.

Preferably, in the step (1), the binder is bentonite,

preferably, the mass ratio of the adhesive in the raw materials is 6-13%.

Preferably, in the step (2), the particle size of the raw material balls is 6-8 mm.

Preferably, in the step (3), the drying temperature of the electric heating constant-temperature air drying oven is set to be 100-120 ℃.

Preferably, in the step (4), the temperature of the resistance furnace is set to be 1000-1200 ℃, the heating rate is 10 ℃/min, and the roasting time is 0.5-1 h.

More preferably, in the step (4), the temperature of the resistance furnace is kept for 1 hour when the temperature is raised to 600 ℃, and then the temperature is raised continuously.

The preparation method has the advantages of simple process route, low raw material cost and easy control of the production process, and the prepared sludge carbon-based ozone catalyst has developed pores, high mechanical strength and long service life, can be used for advanced treatment of industrial wastewater such as printing and dyeing, chemical industry and the like, and can also be used in the fields of advanced treatment of biochemical effluent of a sewage treatment plant and the like.

The invention also provides the sludge carbon-based ozone catalyst prepared by the preparation method.

Compared with the prior art, the invention has the main advantages that:

(1) the preparation method has the advantages of simple process route, low raw material cost, easy control of the production process and the like.

(2) The surface of the catalyst prepared by the method is concave-convex, the catalyst has a honeycomb porous structure, more pores can be seen in the catalyst, the pore size is different, the specific surface area is larger, the catalytic generation of OH by active points of the catalyst under the condition of ozone existence is facilitated, and the ozone oxidation efficiency is improved.

(3) The catalyst prepared by the invention has the highest iron content, contains other metal elements such as copper, aluminum, manganese and the like, and also contains more elements such as calcium, phosphorus, silicon, titanium and the like, wherein part of non-metal elements mainly come from peat, and AlFe is generated in the sintering process₂O₄、Al₂O₃And (Fe)_0.6Cr_0.4)₂O₃And the metal oxides can be used as active components for catalytic oxidation of ozone, so that the utilization rate of the ozone is improved.

(4) The catalyst prepared by the invention has high mechanical strength, water insolubility and stable structure, so that the catalyst can be recycled and has long service life.

(5) The sludge storage of the sewage treatment plant is huge, and the sludge carbon is used as a carbon source and an additive of the ozone catalyst, so that the high-valued recycling of the sludge of the sewage treatment plant can be realized.

Drawings

FIG. 1 is a schematic diagram of a preparation process of a sludge carbon-based ozone catalyst according to the present invention;

FIGS. 2a and 2b are SEM photographs of the sludge carbon-based ozone catalyst of example 1;

fig. 3 is an XRD pattern of the sludge carbon-based ozone catalyst of example 1.

Detailed Description

The invention is further described with reference to the following drawings and specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are conducted under conditions not specified, usually according to conventional conditions, or according to conditions recommended by the manufacturer.

The preparation process of the sludge carbon-based ozone catalyst is shown in figure 1 and comprises the steps of raw material mixing, extrusion granulation, drying, high-temperature calcination and cooling.