A silicon-based adsorbent and its application in the treatment of domestic waste incineration waste gas

Abstract

The present invention discloses a silicon-based adsorbent and its application in the treatment of waste gas from the incineration of domestic waste. The silicon-based adsorbent uses a polymer-modified composite clay as a matrix and humic acid is loaded on the surface. The composite clay is a combination of palygorskite, chlorite and illite. The silicon-based adsorbent of the present invention has excellent adsorption performance for dioxins and maintains good mechanical properties in both alkaline and neutral environments. It can effectively solve the problem that humic acid is extremely easy to dissolve in neutral and alkaline environments, expand the application range of the adsorbent, and effectively improve the adsorption rate for dioxins.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental governance, and in particular to a silicon-based adsorbent and its application in the treatment of waste gas from the incineration of domestic waste. Background Art

[0002] Currently, the main methods for treating domestic waste in my country include landfill, incineration, and composting. Compared with landfill and composting, incineration offers advantages such as reduced volume, higher efficiency, and the utilization of heat generated by combustion. It plays a significant role in waste treatment and is gradually becoming the primary method for domestic waste disposal.

[0003] However, the incineration process is prone to producing dioxins. With growing environmental awareness, emission standards for dioxin-like pollutants in flue gas are becoming increasingly stringent. To meet these standards, waste incineration plants generally use activated carbon adsorption to control dioxin emissions. However, activated carbon has a limited adsorption capacity and is relatively weak for dioxins, resulting in poor dioxin adsorption effectiveness.

[0004] To address the poor dioxin adsorption performance of activated carbon, researchers have used humic acid to adsorb dioxins by attaching it to clay or organically or inorganically modified clay. However, since most clays are electrically charged, organic or inorganic modification imparts a positive charge, while humic acid is negatively charged. The mutual attraction between the positive and negative charges creates a humic acid-clay complex. Humic acid adheres to the clay's surface and internal voids, improving its hydrophobicity. Simultaneously, the humic acid also alters the clay's surface charge, thereby enhancing the humic acid-clay complex's ability to adsorb dioxins.

[0005] However, humic acid is easily affected by pH and dissolves easily in neutral and alkaline environments, which in turn reduces its adsorption efficiency for dioxins. Although the use of clay to modify humic acid can reduce its solubility in neutral and alkaline environments and improve its adsorption efficiency for dioxins, the effect is not ideal. Summary of the Invention

[0006] The object of the present invention is to overcome the defects and shortcomings of the prior art and provide a silicon-based adsorbent having excellent adsorption performance for dioxins, maintaining good mechanical properties in both alkaline and neutral environments, effectively solving the problem that humic acid is extremely easy to dissolve in neutral and alkaline environments, expanding the application range of the adsorbent, and effectively improving the adsorption rate for dioxins.

[0007] The present invention aims to provide a silicon-based adsorbent, which has a polymer-modified composite clay as a matrix and a surface-loaded humic acid, wherein the composite clay is a combination of palygorskite, chlorite and illite; and the polymer is prepared by polymerizing 4'-vinyl-4-biphenylcarboxylic acid monomers.

[0008] In some embodiments of the present invention, the mass ratio of palygorskite, chlorite and illite is 1-3:1:1-4.

[0009] In some embodiments of the present invention, the mass ratio of the 4'-vinyl-4-biphenylcarboxylic acid to the composite clay is 1:2-4.

[0010] Another object of the present invention is to provide a method for preparing the silicon-based adsorbent, comprising the following steps:

[0011] S1. Under nitrogen, 4'-vinyl-4-biphenylcarboxylic acid was mixed with water, sodium hydroxide was added, and then the composite clay was added. The temperature was raised, an initiator was added, and the temperature reaction was continued to obtain a polymer-modified composite clay.

[0012] S2. Add dilute sulfuric acid to the polymer-modified composite clay for activation, then add potassium humate aqueous solution, react, and post-treat to obtain a silicon-based adsorbent.

[0013] In some embodiments of the present invention, in S1, the mass ratio of 4'-vinyl-4-bibenzoic acid to sodium hydroxide and initiator is 60-80:10-20:1.

[0014] In some embodiments of the present invention, in S1, the initiator is selected from at least one of ammonium persulfate, sodium persulfate, and potassium persulfate.

[0015] In some embodiments of the present invention, in S1, the heating temperature is 50-70° C. and the time is 20-40 minutes.

[0016] In some embodiments of the present invention, in S1, the temperature of the continued temperature-raising reaction is 80-100° C. and the time is 4-6 hours.

[0017] In some embodiments of the present invention, in S2, the mass ratio of the polymer-modified composite clay to the dilute sulfuric acid and potassium humate solution is 1:8-12:1.5-2.5.

[0018] In some embodiments of the present invention, in S2, the activation temperature is 20-30° C., and the activation time is 20-40 min.

[0019] In some embodiments of the present invention, in S2, the reaction temperature is 20-30° C., and the reaction time is 50-70 min.

[0020] In some embodiments of the present invention, in S2, the mass concentration of the dilute sulfuric acid is 10% to 20%.

[0021] In some embodiments of the present invention, in S2, the mass concentration of the potassium humate aqueous solution is 4% to 6%.

[0022] Another object of the present invention is to provide the use of the silicon-based adsorbent or the silicon-based adsorbent prepared by the preparation method of the silicon-based adsorbent in the treatment of waste gas from the incineration of domestic waste.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] On the one hand, the molecular structure of the poly(4'-vinyl-4-biphenylcarboxylic acid) of the present invention contains a conjugation effect, which enhances the hydrogen bonding between the poly(4'-vinyl-4-biphenylcarboxylic acid) and humic acid. On the other hand, the composite clay of the present invention has a positive charge, and the humic acid has a negative charge. The positive and negative charges attract each other, which enhances the interaction between the composite clay and the humic acid. The interaction between the polymer and the composite clay and the humic acid enables the humic acid to maintain good mechanical properties in both alkaline and neutral environments, effectively solving the problem of humic acid being extremely easy to dissolve in neutral and alkaline environments, and improving the adsorption rate of dioxins. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the concept of the present invention and the technical effects produced in conjunction with the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. The test methods used in the embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can all be reagents and materials obtained from commercial channels.

[0026] Example 1

[0027] This embodiment provides a silicon-based adsorbent, the preparation method of which includes the following steps:

[0028] S1. Under nitrogen, 60 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 360 parts by mass of water, 20 parts by mass of sodium hydroxide was added, and then a mixture of 48 parts by mass of palygorskite, 24 parts by mass of chlorite and 48 parts by mass of illite was added, the temperature was raised to 70 ° C, held for 20 min, 1 part by mass of ammonium persulfate was added, and the temperature was continued to rise to 80 ° C for 6 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0029] S2. Add 80 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 10%, and activate at 20°C for 40 minutes. Then add 15 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 6%, and react at 30°C for 50 minutes. Filter and wash the filter residue with deionized water three times, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0030] Example 2

[0031] This embodiment provides a silicon-based adsorbent, the preparation method of which includes the following steps:

[0032] S1. Under nitrogen, 80 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 500 parts by mass of water, 10 parts by mass of sodium hydroxide was added, and then a mixture of 120 parts by mass of palygorskite, 40 parts by mass of chlorite and 160 parts by mass of illite was added, the temperature was raised to 50 ° C, held for 40 min, 1 part by mass of sodium persulfate was added, the temperature was continued to rise to 100 ° C and the reaction was allowed to react for 4 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0033] S2. Add 120 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 20%, and activate at 30°C for 20 minutes. Then add 25 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 4%, and react at 20°C for 70 minutes. Filter and wash the residue with deionized water three times, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0034] Example 3

[0035] This embodiment provides a silicon-based adsorbent, the preparation method of which includes the following steps:

[0036] S1. Under nitrogen, 70 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 500 parts by mass of water, 15 parts by mass of sodium hydroxide was added, and then a mixture of 70 parts by mass of palygorskite, 70 parts by mass of chlorite and 70 parts by mass of illite was added, the temperature was raised to 60 ° C, held for 30 min, 1 part by mass of potassium persulfate was added, and the temperature was continued to rise to 90 ° C for 5 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0037] S2. Add 100 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes. Then add 20 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes. Filter and wash the filter residue three times with deionized water, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0038] Comparative Example 1

[0039] This comparative example provides a silicon-based adsorbent, the preparation method of which comprises the following steps:

[0040] S1. Under nitrogen, 70 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 500 parts by mass of water, 15 parts by mass of sodium hydroxide was added, and then 210 parts by mass of palygorskite was added. The temperature was raised to 60 ° C and maintained for 30 min. 1 part by mass of potassium persulfate was added and the temperature was continued to rise to 90 ° C for 5 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0041] S2. Add 100 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes. Then add 20 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes. Filter and wash the filter residue three times with deionized water, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0042] Comparative Example 2

[0043] This comparative example provides a silicon-based adsorbent, the preparation method of which comprises the following steps:

[0044] S1. Under nitrogen, 70 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 500 parts by mass of water, 15 parts by mass of sodium hydroxide was added, and then 210 parts by mass of chlorite was added, the temperature was raised to 60 ° C, maintained for 30 min, 1 part by mass of potassium persulfate was added, and the temperature was continued to rise to 90 ° C for 5 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0045] S2. Add 100 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes. Then add 20 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes. Filter and wash the filter residue three times with deionized water, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0046] Comparative Example 3

[0047] This comparative example provides a silicon-based adsorbent, the preparation method of which comprises the following steps:

[0048] S1. Under nitrogen, 70 parts by mass of 4'-vinyl-4-biphenylcarboxylic acid was mixed with 500 parts by mass of water, 15 parts by mass of sodium hydroxide was added, and then 210 parts by mass of illite was added. The temperature was raised to 60 ° C and maintained for 30 min. 1 part by mass of potassium persulfate was added and the temperature was continued to rise to 90 ° C for 5 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0049] S2. Add 100 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes. Then add 20 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes. Filter and wash the filter residue three times with deionized water, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0050] Comparative Example 4

[0051] This comparative example provides a silicon-based adsorbent, the preparation method of which comprises the following steps:

[0052] S1. Under nitrogen, 15 parts by mass of sodium hydroxide was added to 500 parts by mass of water, and then a mixture of 70 parts by mass of palygorskite, 70 parts by mass of chlorite and 70 parts by mass of illite was added, the temperature was raised to 60 ° C, held for 30 min, 1 part by mass of potassium persulfate was added, and the temperature was continued to rise to 90 ° C for 5 hours. The product was washed three times with ethanol, dried and crushed to obtain a polymer-modified composite clay;

[0053] S2. Add 100 parts by mass of dilute sulfuric acid to 10 parts by mass of polymer-modified composite clay, the mass concentration of dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes. Then add 20 parts by mass of potassium humate aqueous solution, the mass concentration of potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes. Filter and wash the filter residue three times with deionized water, adjust the pH value to 10, dry and crush to obtain a silicon-based adsorbent.

[0054] The performance of the silicon-based adsorbents of Examples 1-3 and Comparative Examples 1-4 was tested. The test method is as follows, and the results are shown in Table 1.

[0055] The silicon-based adsorbents prepared in Examples 1-3 and Comparative Examples 1-4 were used to adsorb dioxins. In a domestic waste incineration plant, waste gas purification was carried out using a "SNCR + semi-dry deacidification + flue silicon-based adsorbent injection + bag dust removal" method. The silicon-based adsorbents prepared in Examples 1-3 and Comparative Examples 1-4 were added at a rate of 0.40 kg / t of waste, 0.50 kg / t of waste, and 0.60 kg / t of waste, respectively. Dioxin detection was performed on the waste gas before and after purification treatment according to the method described in "Determination of Dioxins in Ambient Air and Waste Gases by Isotope Dilution High-Resolution Gas Chromatography-High-Resolution Mass Spectrometry" (HJ77.2-2008). The dioxin removal rate was then calculated based on the concentrations before and after treatment.

[0056] Table 1. Properties of silicon-based adsorbents prepared in Examples 1-3 and Comparative Examples 1-4.

[0057]

[0058] As shown in Table 1, the silicon-based adsorbents prepared in Examples 1 to 3 of the present invention can effectively remove dioxins. On the one hand, the silicon-based adsorbents prepared in Examples 1 to 3 of the present invention contain poly(4'-vinyl-4-biphenylcarboxylic acid), and the molecular structures of the silicon-based adsorbents contain conjugation, which enhances the hydrogen bonding between poly(4'-vinyl-4-biphenylcarboxylic acid) and humic acid. On the other hand, the composite clay of the present invention has a positive charge, and the humic acid has a negative charge. The positive and negative charges attract each other, which enhances the interaction between the composite clay and the humic acid. The interaction between the polymer and the composite clay and the humic acid enables the humic acid to maintain good mechanical properties in both alkaline and neutral environments, effectively solving the problem of humic acid being easily soluble in neutral and alkaline environments, and improving the adsorption rate of dioxins. However, the silicon-based adsorbents prepared in Comparative Examples 1 to 4 contain a single clay or do not contain poly(4'-vinyl-4-biphenylcarboxylic acid), which results in an increase in the solubility of humic acid in the silicon-based adsorbent in neutral and alkaline environments, thereby resulting in a decrease in the adsorption rate of dioxins by the silicon-based adsorbent.

[0059] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A silicon-based adsorbent, characterized in that The silicon-based adsorbent uses polymer-modified composite clay as a matrix and humic acid is loaded on the surface. The composite clay is a combination of palygorskite, chlorite and illite. The polymer is prepared by polymerizing 4'-vinyl-4-biphenylcarboxylic acid monomers.

2. The silicon-based adsorbent according to claim 1, characterized in that The mass ratio of the palygorskite, chlorite and illite is 1-3:1:1-4.

3. The silicon-based adsorbent according to claim 1, characterized in that The mass ratio of the 4'-vinyl-4-biphenylcarboxylic acid to the composite clay is 1:2-4.

4. The method for preparing the silicon-based adsorbent according to any one of claims 1 to 3, characterized in that: The steps include: S1. Under nitrogen, 4'-vinyl-4-biphenylcarboxylic acid was mixed with water, sodium hydroxide was added, and then the composite clay was added. The temperature was raised, an initiator was added, and the temperature reaction was continued to obtain a polymer-modified composite clay. S2. Add dilute sulfuric acid to the polymer-modified composite clay for activation, then add potassium humate aqueous solution, react, and post-treat to obtain a silicon-based adsorbent.

5. The method for preparing a silicon-based adsorbent according to claim 4, wherein: In S1, the mass ratio of the 4'-vinyl-4-bibenzoic acid, sodium hydroxide, and initiator is 60-80:10-20:

1.

6. The method for preparing a silicon-based adsorbent according to claim 4, wherein: In S1, the initiator is selected from at least one of ammonium persulfate, sodium persulfate, and potassium persulfate.

7. The method for preparing a silicon-based adsorbent according to claim 4, wherein: In S1, the heating temperature is 50-70°C and the time is 20-40 minutes; The temperature of the continued temperature-raising reaction is 80-100° C. and the time is 4-6 hours.

8. The method for preparing a silicon-based adsorbent according to claim 4, wherein: In S2, the mass ratio of the polymer-modified composite clay to the dilute sulfuric acid and potassium humate solution is 1:8-12:1.5-2.5; The activation temperature is 20-30°C and the activation time is 20-40 minutes; The reaction temperature is 20-30° C. and the reaction time is 50-70 min.

9. The method for preparing a silicon-based adsorbent according to claim 4, wherein: In S2, the mass concentration of the potassium humate aqueous solution is 4% to 6%; The mass concentration of the dilute sulfuric acid is 10% to 20%.

10. Use of the silicon-based adsorbent according to any one of claims 1 to 3 or the silicon-based adsorbent prepared by the preparation method of the silicon-based adsorbent according to any one of claims 4 to 9 in the treatment of waste gas from domestic waste incineration.

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