CN114259980A

CN114259980A - Method for preparing heavy metal adsorption stabilizer by using entrained flow bed gasified fine ash

Info

Publication number: CN114259980A
Application number: CN202111634094.4A
Authority: CN
Inventors: 初茉; 孙星博; 吕飞勇; 袁旖璠
Original assignee: China University of Mining and Technology Beijing CUMTB
Current assignee: China University of Mining and Technology Beijing CUMTB
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2022-04-01

Abstract

The invention relates to a method for preparing a heavy metal adsorption stabilizer by using entrained flow bed coal gasification fine ash, belonging to the technical field of solid waste resource utilization. According to the invention, the entrained flow bed gasified fine ash is taken as a main body, and is modified by the combination of potassium permanganate and hydrochloric acid, so that the adsorption effect of the gasified fine ash on heavy metal ions is improved. The preparation process of the heavy metal adsorption stabilizer is shown in figure 1. The adsorbent provided by the invention is used for adsorbing Pb²⁺The removal rate of the catalyst can reach more than 90.00 percent, and the catalyst is used for removing Cd²⁺The removal rate of the adsorbent can reach more than 99.00 percent, and is higher than that of common adsorbents such as diatomite, zeolite and the like; the adsorbent has excellent environmental adaptability, and can be kept in an acidic environment (pH 3-6)And (4) adsorption stability.

Description

Method for preparing heavy metal adsorption stabilizer by using entrained flow bed gasified fine ash

Technical Field

The invention relates to a method for preparing a heavy metal adsorption stabilizer by using entrained flow bed coal gasification fine ash. The adsorbent prepared by the method is used for treating the wastewater containing heavy metals, and can effectively remove heavy metal ions such as lead, cadmium and the like in the acidic wastewater. The invention discloses coal gasification fine ash, belongs to typical solid waste, and belongs to the technical field of solid waste resource utilization.

Background

With the rapid development of industry, heavy metal pollution events occur frequently. Lead, cadmium and the like belong to high-risk heavy metals, are difficult to naturally degrade, can be continuously enriched through a food chain, and pose great threats to the natural environment and the human health. The removal and purification of heavy metals in water bodies become one of the key and difficult points of industrial and mining wastewater treatment.

At present, the conventional methods for treating heavy metal sewage include an ion exchange method, a chemical precipitation method, a membrane separation method, an electrochemical treatment method and an adsorption method. Compared with other methods for removing heavy metal ions in water, the adsorption method is economic and environment-friendly, has high removal efficiency and simple and flexible operation and design, and is the most economic and effective heavy metal wastewater treatment method recognized at present.

In recent years, the high-efficiency clean utilization technology of coal based on coal gasification is rapidly developed in China, and a large amount of gasification ash is generated along with a coal gas product in the coal gasification process. Gasification ash can be divided into coarse slag and fine ash, and the source of the fine ash is divided into two parts: one part of the low-density particles carried by the raw gas is obtained by collecting the low-density particles by a demister; the other part is fine ash formed after coal gasification, and the fine ash is carried by cooling water, passes through a black water treatment system and is removed by a filter press to form a filter cake. The gasified fine ash has huge yield, is treated by landfill or stockpiling at present, occupies a large amount of land, has fine particles and low density, and is easy to fly under the action of wind power in the process of stockpiling and transportation to cause serious atmospheric pollution. As an important component of coal-based solid waste, the resource and high-value utilization of the coal gasification fine ash are highly regarded. Research shows that the surface of the gasified fine ash generated in the gasification process has a porous structure and presents the characteristic of large specific surface area, and the fine ash has high unburned carbon content and has the potential of preparing an adsorbent.

The manganese oxide has the advantages of large specific surface area, many surface adsorption sites, strong adsorption capacity and the like, and is commonly used for removing heavy metal ions in water. However, because the particles are fine, the manganese oxide is easy to disperse in water and has high separation difficulty, and the application of the manganese oxide in the treatment of heavy metal wastewater is limited.

Based on the structural characteristics of porous surface, large specific surface area, stable structure and easy separation and recovery of the gasified fine ash, the invention uses potassium permanganate as a modifier to carry out redox reaction with concentrated hydrochloric acid, and a layer of manganese oxide is loaded on the surface and pore channels of the gasified fine ash, thereby greatly improving the specific surface area of the gasified fine ash and being beneficial to the adsorption of adsorbate on the surface of the gasified fine ash. On the other hand, the number of functional groups on the surface of the gasified fine ash can be improved, new hydroxyl groups are formed, and more active sites are provided for heavy metal ion adsorption. The loading of the manganese oxide, the increase of the specific surface area of the gasified fine ash and the increase of the number of oxygen-containing functional groups on surface active sites improve the adsorption performance of the gasified fine ash on heavy metal ions.

The potassium permanganate and the concentrated hydrochloric acid are combined to modify the gasified fine ash to prepare the adsorption stabilizer with high-efficiency adsorption performance on heavy metal ions, so that a solution is provided for heavy metal sewage treatment, and a new idea is provided for resource utilization of solid wastes.

Disclosure of Invention

The invention aims to provide an entrained flow bed coal gasification fine ash adsorption stabilizer, which is prepared by taking entrained flow bed coal gasification fine ash as a main raw material, adding a potassium permanganate modifier in a certain proportion, and performing modification processing.

The technical scheme adopted by the invention is as follows:

a method for preparing a heavy metal adsorption stabilizer by using entrained flow bed gasified fine ash is obtained by the following steps:

taking 10g of coal gasification fine ash, repeatedly washing with deionized water to remove surface impurities, and drying in a drying oven at 105 ℃ for 4 h.

And adding 30-100 mL of 0.4mol/L potassium permanganate solution into the dried gasified fine ash according to the solid-to-liquid ratio of 1: 3-1: 10, heating at 150 ℃, and continuously stirring until the mixture is boiled in the heating process.

Continuously stirring, and slowly dropwise adding 0.3-1.0 mL of concentrated hydrochloric acid (V) into the boiling mixed solution_KMnO4/V_HCl10:1), the reaction was continued for 0.5h and cooled to room temperature.

And (3) carrying out centrifugal separation on the obtained sample, repeatedly washing a solid phase product to be neutral by using deionized water, and drying the solid phase product in a drying oven at 105 ℃ for 24 hours to obtain the coal gasification fine ash heavy metal adsorbent.

The invention provides a method for utilizing coal gasification fine ash, and develops a resource utilization way of coal-based solid waste. The adsorbent prepared by the method takes industrial waste as a main raw material, and the heavy metal adsorption stabilizer is obtained by modification treatment. The adsorption stabilizer obtained by the method has excellent performance in adsorption experiments of heavy metal lead and cadmium ions.

Drawings

FIG. 1 is a schematic view of the preparation process of the heavy metal adsorption stabilizer of the present invention

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples and comparative examples, which are not intended to limit the scope of the present invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are available from regular distributors.

The following examples all use the gasified fine ash produced by the dry powder pressure gasification process.

The adsorption stabilizers of examples 1 to 5 were all prepared as follows:

taking 10g of coal gasification fine ash, repeatedly washing with deionized water to remove surface impurities, and drying in a drying oven at 105 ℃ for 4 h. Adding potassium permanganate solution with the concentration of 0.4mol/L into the dried gasified fine ash according to different solid-to-liquid ratios, heating at 150 ℃, and continuously stirring in the heating process until the mixture is boiled. Slowly dropwise adding concentrated hydrochloric acid (V) into the boiling mixed solution_KMnO4/V_HCl10:1), the reaction was continued for 0.5h and cooled to room temperature. And (3) carrying out centrifugal separation on the obtained sample, repeatedly washing a solid phase product to be neutral by using deionized water, and drying the solid phase product in a drying oven at 105 ℃ for 24 hours to obtain the heavy metal ion adsorption stabilizer.

Example 1:

the solid-liquid ratio of the adsorbent is 1:3, the dropping amount of concentrated hydrochloric acid is 0.3 mL.

Measurement of adsorption Properties: taking the adsorbent prepared by the patent, and treating Pb according to the adding amount of 2g/L²⁺The initial concentration is 100mg/L, the solution pH is 5 simulation sewage, the adsorption experiment is carried out in a constant temperature water bath oscillator, the constant temperature oscillation adsorption is carried out at 30 ℃, the rotation speed is 150rpm, and the adsorption is carried out for 24 h. The adsorption capacity was 44.93mg/g, and the removal rate was 90.00%.

Example 2:

Measurement of adsorption Properties: taking the adsorbent prepared by the patent, and treating Pb according to the adding amount of 2g/L²⁺The initial concentration is 100mg/L, the solution pH is 4 simulation sewage, the adsorption experiment is carried out in a constant temperature water bath oscillator, the constant temperature oscillation adsorption is carried out at 30 ℃, the rotation speed is 150rpm, and the adsorption is carried out for 24 h. The adsorption capacity was 49.36mg/g, and the removal rate was 99.11%.

Example 3:

Measurement of adsorption Properties: taking the adsorbent prepared by the patent, and treating Pb according to the adding amount of 2g/L²⁺The initial concentration is 100mg/L, the solution pH is 3 simulation sewage, the adsorption experiment is carried out in a constant temperature water bath oscillator, the constant temperature oscillation adsorption is carried out at 30 ℃, the rotation speed is 150rpm, and the adsorption is carried out for 24 h. The adsorption capacity was 49.44mg/g, and the removal rate was 99.49%.

Example 4:

the solid-liquid ratio of the adsorbent is 1:10, the dropping amount of concentrated hydrochloric acid is 1.0 mL.

Measurement of adsorption Properties: taking the adsorbent prepared by the patent, and treating Pb according to the adding amount of 2g/L²⁺The initial concentration is 100mg/L, the solution pH is 5 simulation sewage, the adsorption experiment is carried out in a constant temperature water bath oscillator, the constant temperature oscillation adsorption is carried out at 30 ℃, the rotation speed is 150rpm, and the adsorption is carried out for 24 h. The adsorption capacity was 45.97mg/g, and the removal rate was 92.00%.

Example 5:

Measurement of adsorption Properties:taking the adsorbent prepared by the method, and treating Cd according to the adding amount of 2g/L²⁺The adsorption experiment was carried out in a constant temperature water bath oscillator using simulated wastewater with an initial concentration of 100mg/L and a solution pH of 6, and the adsorption was carried out at a constant temperature of 30 ℃ and 150rpm for 24 hours. The adsorption capacity was 51.98mg/g, and the removal rate was 99.70%.

Comparative example 1:

the adsorbent is diatomite; adsorption performance under the same conditions as the operating and experimental conditions of examples 1, 4: the adsorption capacity was 3.96mg/g, and the removal rate was 39.60%.

Comparative example 2:

the adsorbent is diatomite; adsorption performance under the same conditions as the operating and experimental conditions of example 5: the adsorption capacity was 1.583mg/g, and the removal rate was 15.83%.

Comparative example 3:

the adsorbent is zeolite; adsorption performance under the same conditions as the operating and experimental conditions of examples 1, 4: the adsorption capacity was 22.81mg/g, and the removal rate was 45.62%.

Comparative example 4:

the adsorbent is zeolite; adsorption performance under the same conditions as the operating and experimental conditions of example 5: the adsorption capacity was 19.67mg/g, and the removal rate was 39.34%.

As described above, although the embodiments of the present invention have been described in detail, it will be apparent to those skilled in the art that many modifications are possible without substantially departing from the spirit and scope of the present invention. Therefore, such modifications are also all included in the scope of protection of the present invention.

Claims

1. A method for preparing a heavy metal adsorption stabilizer by using entrained flow coal gasification fine ash is characterized by comprising the following steps:

(1) taking gasified fine ash or filter cake, repeatedly washing to remove surface impurities, and drying for 4h at 100-105 ℃;

(2) adding 0.4mol/L potassium permanganate solution (the solid-to-liquid ratio is 1: 3-1: 10) into the dried gasified fine ash, heating at 150 ℃, and continuously stirring until the mixture is boiled in the heating process;

(3) continuously stirring, slowly dropwise adding concentrated hydrochloric acid (V) into the boiling mixed solution_KMnO4/V_HCl10:1), continuing the reaction for 0.5h, and cooling to room temperature;

(4) and (3) repeatedly washing the obtained solid-phase product to be neutral according to the steps (1), (2) and (3), and drying at 100-105 ℃ for 24h to obtain the coal gasification fine ash heavy metal adsorption stabilizer.

2. The heavy metal adsorbent prepared according to the method 1-4 is applied to treatment of lead-and cadmium-containing wastewater, and is characterized in that: under the conditions that the concentration of lead ions and cadmium ions in the wastewater is 100mg/L, pH-3-6 and the input amount of the adsorbent is 2-4 g/L, the adsorption amount can reach 45.97mg/g and 51.98mg/g, and the removal rate is more than 90.00%.