Carbonized regenerated aerated concrete adsorption material as well as preparation method and application thereof

Abstract

The invention provides a carbonized regenerated aerated concrete adsorption material as well as a preparation method and application thereof. The preparation method of the carbonized and regenerated aerated concrete adsorption material comprises the following steps: S1, crushing waste aerated concrete, ball-milling, and sieving to obtain aerated concrete fine powder; s2, carbonizing the aerated concrete fine powder with carbon dioxide, and controlling the carbonization temperature to be 15-25 DEG C, the humidity to be 65-75% and the concentration of carbon dioxide to be 18-22%, so as to obtain the carbonized regenerated aerated concrete adsorption material. The waste aerated concrete and the carbon dioxide are used as main raw materials, the utilization value of the waste aerated concrete is improved, meanwhile, the carbon dioxide is effectively sealed and stored, and the prepared carbonized regenerated aerated concrete adsorption material can be used in a wider pH condition, and is high in adsorption capacity and good in adsorption effect. The adsorption capacity on heavy metal ions in sewage is extremely high.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a carbonized regenerated aerated concrete adsorption material and a preparation method and application thereof. Background Art

[0002] During the process of house demolition and renovation, a large amount of waste aerated concrete is generated. Due to the low strength of waste aerated concrete, it is difficult to use it to produce recycled aggregate or as a road cushion material like high-strength concrete. Waste aerated concrete is light in weight and large in volume, and conventional stacking methods occupy a large amount of land resources; in addition, waste aerated concrete contains alkaline ions, and the pH value of its leachate exceeds 11, which will cause serious damage to the ecological balance of the surrounding soil and water bodies. Therefore, finding ways to recycle waste aerated concrete has received increasing attention.

[0003] Heavy metal pollution is one of the main sources of the increasingly serious global water pollution problem. With the rapid development of industries such as metal electroplating, mining, fertilizers, leather making, batteries, papermaking, and pesticides, a large amount of wastewater containing heavy metals is continuously produced and discharged into the natural environment. Heavy metal ions are difficult to degrade, accumulate over a long period of time, are toxic, difficult to metabolize, and concealed. After being ingested by animals, plants, and humans, they combine with molecules in the body and accumulate in the body to exceed a certain concentration, causing abnormalities and toxicity in the body, which seriously endangers the ecological environment and the health of natural organisms.

[0004] At present, the common methods for treating heavy metal wastewater include dilution, adsorption, membrane filtration, physical flocculation, chemical precipitation, ion exchange, electrochemical method, phytoremediation and biosorption. Among them, adsorption has attracted extensive attention and research due to its simplicity, high efficiency and low cost. Adsorption is the use of the high specific surface area or functional groups of the adsorbent material to adsorb pollutants in wastewater. The micropores, high specific surface area, cavities and developed channels constitute physical adsorption and other effects. The key to the study of adsorption is to prepare efficient heavy metal adsorbents. Although synthetic adsorbent materials such as activated carbon and chitosan have strong adsorption capacity and a wide range of applications, they have high costs and the production process is not environmentally friendly, which seriously restricts their utilization in many factory wastewater treatment. Natural minerals and modified agricultural, mining and industrial wastes can be used as adsorbents, but they have problems such as small adsorption capacity, poor adsorption capacity and limited applicable pH.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a carbonized regenerated aerated concrete adsorbent material and a preparation method and application thereof. The carbonized regenerated aerated concrete adsorbent material has a high adsorption capacity, is applicable to a wide pH range, and has a very strong adsorption capacity for heavy metal ions in sewage.

[0007] The present invention provides a method for preparing a carbonized regenerated aerated concrete adsorbent material, comprising the following steps:

[0008] S1: crushing the waste aerated concrete, ball milling and sieving to obtain aerated concrete fine powder;

[0009] S2: Carbonizing aerated concrete fine powder with carbon dioxide, controlling the temperature during carbonization to be 15-25°C, the humidity to be 65-75%, and the concentration of carbon dioxide to be 18-22%, to obtain a carbonized regenerated aerated concrete adsorption material.

[0010] In step S1, an automatic ball mill can be used for ball milling, and the ball milling time is controlled to be 5-6 hours; after ball milling, the product is sieved with a 100-mesh screen.

[0011] In step S2, various parameters of carbonization are precisely controlled; specifically, the temperature during carbonization is controlled to be 15-25°C, for example, 15-22°C, the humidity is 65-75%, and the concentration of carbon dioxide is 18-22%, for example, 18-20%. In addition, the carbonization time is controlled to be 10-12d, for example, 12d, the pressure of carbon dioxide is 0.1Mpa, and carbon dioxide can be industrially applied carbon dioxide with a purity of not less than 99%. The carbonization process adopts a dry carbonization form, and the model of the carbonization box is, for example, CABR-HTX12, to ensure the consistency and stability of the carbonization effect; the surface of the carbonized regenerated aerated concrete adsorption material after carbonization changes from gray to yellow, and after SEM imaging, it is shown that there are a large number of nano-calcium carbonate and three-dimensional amorphous silica gel and other products on its surface; the above-mentioned carbonization process reconstructs the chemical components of aerated concrete, so that carbonization products such as nano-calcium carbonate and three-dimensional porous structure amorphous silica gel are formed on its surface, which has a strong adsorption capacity for heavy metal ions in sewage, and greatly improves the adsorption capacity of the adsorption material.

[0012] The particle size distribution of the carbonized regenerated aerated concrete adsorption material prepared above is: the volume proportion of particles with a size <100nm is <0.1%, the volume proportion of particles with a size of 100nm-1μm is 2-3%, the volume proportion of particles with a size of 1-10μm is 25-26%, the volume proportion of particles with a size of 10-100μm is 64-66%, and the volume proportion of particles with a size >100μm is 7-8%.

[0013] The specific surface area of ​​the carbonized regenerated aerated concrete adsorbent material prepared above is 5-6m 2 / g, pore volume is 0.03-0.05cm 3 / g, pore diameter (Pore Diameter Dv) is 3-5nm.

[0014] The present invention also provides a carbonization regeneration aerated concrete adsorption material, which is prepared according to the above preparation method.

[0015] The present invention also provides application of the carbonization regeneration aerated concrete adsorption material in treating heavy metal polluted wastewater.

[0016] Specifically, heavy metals include but are not limited to at least one of nickel, cadmium, lead, cobalt, zinc, manganese and copper; the content of heavy metals in the treated heavy metal-contaminated wastewater can be 5-15 mg / L; the dosage ratio of heavy metal-contaminated wastewater to carbonization regenerated aerated concrete adsorption material can be 1L: (10-150) mg; the treatment time can be 10-30 min, for example 20 min; the adsorption capacity of carbonization regenerated aerated concrete adsorption material for heavy metals is 70-1000 mg / g.

[0017] The present invention does not impose strict restrictions on the application of the carbonized regenerated aerated concrete adsorption material in treating heavy metal polluted wastewater. The carbonized regenerated aerated concrete adsorption material can be further used in combination with other precipitation, filter pressing, centrifugal separation and wastewater treatment technologies to purify the heavy metal polluted wastewater. In addition, in industrial production applications, fixed bed adsorption and other methods can be used to treat heavy metal polluted wastewater. During the treatment, the carbonized regenerated aerated concrete adsorption material can be added to the fixed bed adsorber to replace the activated carbon to form an integrated adsorption device.

[0018] The implementation of the present invention has at least the following advantages:

[0019] 1. The preparation method of the present invention uses waste aerated concrete and carbon dioxide as main raw materials, which can not only effectively utilize the waste aerated concrete, but also consume 300kg of carbon dioxide for each ton of carbonized regenerated aerated concrete adsorption material produced. The carbon dioxide is converted into carbonate minerals for effective storage, thereby preventing it from being released back into the air, which helps to reduce the carbon dioxide content in the atmosphere, alleviates the current pressure on the treatment of waste aerated concrete, and is of great significance for alleviating the problem of global warming.

[0020] 2. The preparation method of the present invention performs carbonization treatment after ball-milling and screening of waste aerated concrete, so that the chemical components of the aerated concrete are reconstructed, and a variety of carbonized products with excellent adsorption properties, such as nano calcium carbonate and three-dimensional porous amorphous silica gel, are formed on its surface. The entire product production process is pollution-free, and the prepared adsorption material has a strong adsorption capacity for heavy metal ions in sewage, which greatly improves the adsorption capacity of the adsorption material.

[0021] 3. The carbonized regenerated aerated concrete adsorption material of the present invention has great advantages in actual adsorption capacity, which significantly exceeds the adsorption capacity of other natural adsorption materials or modified regenerated adsorption materials. The adsorption capacity is greatly improved compared with previous waste modification materials, and can be used under a wider range of pH conditions. It has stronger versatility and is excellent in removing heavy metal ions from industrial wastewater such as electroplating, metallurgy, dyes, and chemicals. It not only provides a new solution for the recycling of waste aerated concrete, but also opens up a broader application field for carbon dioxide emission reduction and resource utilization. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] The method for preparing the carbonized regenerated aerated concrete adsorbent material of this embodiment comprises the following steps:

[0027] 1) Raw material pretreatment

[0028] The waste aerated concrete was first crushed, then ball-milled for 6 hours using an automatic ball mill, and then passed through a 100-mesh sieve to obtain aerated concrete fine powder.

[0029] 2) Carbonization treatment

[0030] The aerated concrete fine powder of step 1) is placed in a CABR-HTX12 concrete carbonization test box and carbonized under the set carbonization conditions. The carbonization conditions include: controlling the temperature during carbonization to 20°C, the humidity to 70%, the concentration of carbon dioxide to 20%, and ensuring that the pressure of carbon dioxide is 0.1 MPa. After carbonization for 12 days, the gray aerated concrete fine powder is converted into light yellow carbonized regenerated aerated concrete powder, and the carbonized regenerated aerated concrete adsorption material is obtained.

[0031] The carbonized regenerated aerated concrete adsorbent material prepared above was tested; the results showed that the particle size distribution of the carbonized regenerated aerated concrete adsorbent material was as follows: the volume proportion of particles with a diameter <100nm was 0.04%, the volume proportion of particles with a diameter of 100nm-1μm was 2.24%, the volume proportion of particles with a diameter of 1-10μm was 25.3%, the volume proportion of particles with a diameter of 10-100μm was 64.96%, and the volume proportion of particles with a diameter >100μm was 7.46%; the specific surface area was 5.389m 2 / g, pore volume is 0.032cm 3 / g, and the pore size is 3.828nm.

[0032] 30 mg of the prepared carbonized regenerated aerated concrete adsorption material was added to a 3L plastic bottle containing 30 mg of lead ions, and the bottle was allowed to stand for 20 minutes. The carbonized regenerated aerated concrete adsorption material was filtered to remove the purified water, and the lead ion content in the water was detected. The results showed that there were 0.09 mg of lead ions remaining in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorption material for lead ions in sewage was as high as 997 mg / g.

[0033] Example 2

[0034] The method for preparing the carbonized regenerated aerated concrete adsorbent material of this embodiment comprises the following steps:

[0035] 1) Raw material pretreatment

[0036] The waste aerated concrete was first crushed, then ball-milled for 5 hours using an automatic ball mill, and then passed through a 100-mesh sieve to obtain aerated concrete fine powder.

[0037] 2) Carbonization treatment

[0038] The aerated concrete fine powder of step 1) is placed in a CABR-HTX12 concrete carbonization test box and carbonized under the set carbonization conditions. The carbonization conditions include: controlling the temperature during carbonization to be 18°C, the humidity to be 65%, the concentration of carbon dioxide to be 20%, and ensuring that the pressure of carbon dioxide is 0.1 MPa. After carbonization for 12 days, the gray aerated concrete fine powder is converted into light yellow carbonized regenerated aerated concrete powder, and the carbonized regenerated aerated concrete adsorption material is obtained.

[0039] To a 600 mL plastic bottle containing 6 mg cadmium ions, 30 mg of the prepared carbonized regenerated aerated concrete adsorbent material was added, the bottle was allowed to stand for 20 min, the carbonized regenerated aerated concrete adsorbent material was removed by filtration, purified water was obtained, and the cadmium ion content in the water was detected; the results showed that: 0.03 mg of cadmium ions remained in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent for cadmium ions in sewage was as high as 199 mg / g.

[0040] Example 3

[0041] The method for preparing the carbonized regenerated aerated concrete adsorbent material of this embodiment comprises the following steps:

[0042] 1) Raw material pretreatment

[0043] The waste aerated concrete was first crushed, and then ball-milled for 5.5 hours using an automatic ball mill. After ball-milling, it was sieved through a 100-mesh sieve to obtain aerated concrete fine powder.

[0044] 2) Carbonization treatment

[0045] The aerated concrete fine powder of step 1) is placed in a CABR-HTX12 concrete carbonization test box and subjected to carbonization treatment under set carbonization conditions, wherein the carbonization conditions include: controlling the temperature during carbonization to be 22° C., the humidity to be 75%, the concentration of carbon dioxide to be 20%, and ensuring that the pressure of carbon dioxide is 0.1 MPa. After carbonization for 12 days, the gray aerated concrete fine powder is converted into light yellow carbonized regenerated aerated concrete powder, thereby obtaining a carbonized regenerated aerated concrete adsorption material.

[0046] To a 450 mL plastic bottle containing 4.5 mg of cobalt ions, 30 mg of the prepared carbonized regenerated aerated concrete adsorbent material was added, the bottle was allowed to stand for 20 min, the carbonized regenerated aerated concrete adsorbent material was filtered to remove the purified water, and the cobalt ion content in the water was detected; the results showed that there were 0.06 mg of cobalt ions remaining in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent for cadmium ions in sewage was as high as 148 mg / g.

[0047] Example 4

[0048] The method for preparing the carbonized regenerated aerated concrete adsorbent material of this embodiment comprises the following steps:

[0049] 1) Raw material pretreatment

[0050] The waste aerated concrete was first crushed, then ball-milled for 6 hours using an automatic ball mill, and then passed through a 100-mesh sieve to obtain aerated concrete fine powder.

[0051] 2) Carbonization treatment

[0052] The aerated concrete fine powder of step 1) is placed in a CABR-HTX12 concrete carbonization test box and carbonized under the set carbonization conditions. The carbonization conditions include: controlling the temperature during carbonization to be 15°C, the humidity to be 70%, the concentration of carbon dioxide to be 18%, and ensuring that the pressure of carbon dioxide is 0.1 MPa. After carbonization for 12 days, the gray aerated concrete fine powder is converted into light yellow carbonized regenerated aerated concrete powder, and the carbonized regenerated aerated concrete adsorption material is obtained.

[0053] To a plastic bottle containing 230 mL of 2.3 mg of nickel ions, 30 mg of the prepared carbonized regenerated aerated concrete adsorbent material was added, the bottle was allowed to stand for 20 min, the carbonized regenerated aerated concrete adsorbent material was filtered to remove the purified water, and the nickel ion content in the water was detected; the results showed that there were 0.02 mg of nickel ions remaining in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent for cadmium ions in sewage was as high as 76 mg / g.

[0054] Comparative Example 1

[0055] 30 mg of the aerated concrete fine powder of step 1) in Example 1 was added to a 3L plastic bottle containing 30 mg of lead ions, and the mixture was allowed to stand for 20 min. The aerated concrete fine powder was filtered to remove the purified water, and the lead ion content in the water was detected. The results showed that 22.5 mg of lead ions remained in the water, and the adsorption capacity of the uncarbonated aerated concrete fine powder for lead ions in sewage was only 250 mg / g.

[0056] Comparative Example 2

[0057] Except that the product was milled in an automatic ball mill for 4 h and then passed through a 50-mesh sieve in step 1), the rest was basically the same as in Example 1.

[0058] The carbonized regenerated aerated concrete adsorbent material prepared in this control example was tested; the results showed that the particle size distribution of the carbonized regenerated aerated concrete adsorbent material in this control example was: the volume proportion of particles with a diameter of 100nm-1μm was 2.8%, the volume proportion of particles with a diameter of 1-10μm was 19.9%, the volume proportion of particles with a diameter of 10-100μm was 32.7%, and the volume proportion of particles with a diameter of >100μm was 44.6%; the specific surface area was 4.173m 2 / g, pore volume is 0.025cm 3 / g, and the pore size is 2.798nm.

[0059] 30 mg of the carbonized regenerated aerated concrete adsorbent material of this control example was added to a 3L plastic bottle containing 30 mg of lead ions, and the bottle was allowed to stand for 20 minutes. The carbonized regenerated aerated concrete adsorbent material was filtered to remove the purified water, and the lead ion content in the water was detected. The results showed that 15 mg of lead ions remained in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent material for lead ions in sewage was 500 mg / g.

[0060] Comparative Example 3

[0061] Except that the product was milled in an automatic ball mill for 8 h and then passed through a 200-mesh sieve in step 1), the rest was basically the same as in Example 1.

[0062] The carbonized regenerated aerated concrete adsorbent material prepared in this control example was tested; the results showed that the particle size distribution of the carbonized regenerated aerated concrete adsorbent material in this control example was: the volume proportion of particles with a diameter <100nm was 9.9%, the volume proportion of particles with a diameter of 100nm-1μm was 15.6%, the volume proportion of particles with a diameter of 1-10μm was 48.3%, and the volume proportion of particles with a diameter of 10-100μm was 26.2%; the specific surface area was 6.557m 2 / g, pore volume is 0.029cm 3 / g, and the pore size is 3.143nm.

[0063] 30 mg of the carbonized regenerated aerated concrete adsorbent material of this control example was added to a 3L plastic bottle containing 30 mg of lead ions, and the mixture was allowed to stand for 20 min. The carbonized regenerated aerated concrete adsorbent material was filtered to remove the purified water, and the lead ion content in the water was detected. The results showed that 11.49 mg of lead ions remained in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent material for lead ions in sewage was 617 mg / g.

[0064] Comparative Example 4

[0065] Except for the different carbonization conditions in step 2), the rest is basically the same as Example 1; the carbonization conditions of this comparative example include: controlling the temperature during carbonization to be 20°C, the humidity to be 60%, the concentration of carbon dioxide to be 70%, using industrial combustion waste gas as the source of carbon dioxide. At the same time, ensuring that the pressure of carbon dioxide is 0.07Mpa, and carbonization for 12 days.

[0066] 30 mg of the carbonized regenerated aerated concrete adsorbent material of this control example was added to a 3L plastic bottle containing 30 mg of lead ions, and the bottle was allowed to stand for 20 minutes. The carbonized regenerated aerated concrete adsorbent material was filtered to remove the purified water, and the lead ion content in the water was detected. The results showed that 15.72 mg of lead ions remained in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorbent material for lead ions in sewage was 476 mg / g.

[0067] Comparative Example 5

[0068] Except for using blast furnace slag to replace the waste aerated concrete in Example 1, the rest is basically the same as Example 1.

[0069] 30 mg of blast furnace slag of this control example was added to a 3L plastic bottle containing 30 mg of lead ions, and the bottle was allowed to stand for 20 minutes. The blast furnace slag was filtered out to obtain purified water, and the lead ion content in the water was tested. The results showed that 29.1 mg of lead ions remained in the water, and the adsorption capacity of the carbonized regenerated aerated concrete adsorption material for lead ions in sewage was 30 mg / g.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a carbonized regenerated aerated concrete adsorbent material, characterized in that: The steps include: S1: crushing the waste aerated concrete, ball milling and sieving to obtain aerated concrete fine powder; S2: Carbonizing aerated concrete fine powder with carbon dioxide, controlling the temperature during carbonization to be 15-25°C, the humidity to be 65-75%, and the concentration of carbon dioxide to be 18-22%, to obtain a carbonized regenerated aerated concrete adsorption material.

2. The preparation method according to claim 1, characterized in that: Control the ball milling time to 5-6h; control the carbonization time to 10-12d.

3. The preparation method according to claim 1, characterized in that: The particle size distribution of carbonized regenerated aerated concrete adsorption material is: the volume proportion of particles with a size of <100nm is <0.1%, the volume proportion of particles with a size of 100nm-1μm is 2-3%, the volume proportion of particles with a size of 1-10μm is 25-26%, the volume proportion of particles with a size of 10-100μm is 64-66%, and the volume proportion of particles with a size of >100μm is 7-8%.

4. The preparation method according to claim 1, characterized in that: The specific surface area of ​​carbonized regenerated aerated concrete adsorption material is 5-6m 2 / g, pore volume is 0.03-0.05cm 3 / g, pore size is 3-5nm.

5. A carbonized regenerated aerated concrete adsorption material, characterized in that: Prepared according to any one of the preparation methods of claims 1-4.

6. Use of the carbonized regenerated aerated concrete adsorbent material according to claim 5 in treating heavy metal contaminated wastewater.

7. The use according to claim 6, characterized in that: The heavy metal is selected from at least one of nickel, cadmium, lead, cobalt, zinc, manganese and copper.

8. The use according to claim 6, characterized in that: The content of heavy metals in the treated heavy metal polluted wastewater is 5-15mg / L.

9. The use according to claim 6, characterized in that: The dosage ratio of heavy metal polluted wastewater to carbonization regeneration aerated concrete adsorption material is 1L: (10-150) mg; the treatment time is 10-30 min.

10. The use according to claim 6, characterized in that: The adsorption capacity of carbonized regenerated aerated concrete adsorption material for heavy metals is 70-1000 mg / g.