Silicon-based adsorbents and their application in the treatment of food waste incineration exhaust gas

Abstract

To provide a silicon-based adsorbent capable of effectively adsorbing dioxins in exhaust gas from incinerating food waste, a method for producing the same, and applications thereof. [Solution] A silicon-based adsorbent and its application in the treatment of exhaust gas from food waste incineration is disclosed. The silicon-based adsorbent has a polymer-modified composite clay base with humic acid supported on the surface, the composite clay being a combination of palygorskite, chlorite, and illite. The silicon-based adsorbent of the present invention has excellent adsorption performance for dioxins and can maintain good mechanical properties even in alkaline and neutral environments, effectively solving the problem that humic acid is highly soluble in neutral and alkaline environments, expanding the application range of the adsorbent, and effectively improving the adsorption rate for dioxins.

Description

[Technical Field]

[0001] The present invention relates to the field of environmental improvement technology, and more particularly to a silicon-based adsorbent and its application in the treatment of flue gas from incineration of food waste. [Background technology]

[0002] Currently, food waste disposal methods in China mainly include landfilling, incineration, and composting. Compared to landfilling and composting, incineration has the advantages of reducing the amount and volume of waste, increasing the level of sophistication, and enabling the use of heat from combustion. It plays an important role in waste disposal and is gradually becoming the main route for food waste disposal.

[0003] However, dioxins are easily generated during incineration, and with growing awareness of environmental protection, people are setting increasingly strict emission standards for dioxin-like pollutants in smoke. To meet these standards, waste incineration plants often adopt activated carbon adsorption methods to control dioxin emissions. However, activated carbon has limited adsorption capacity and weak dioxin adsorption ability, making the adsorption effect of activated carbon low.

[0004] To solve the problem of activated carbon's low dioxin adsorption efficiency, researchers have immobilized humic acid on clay or organically or inorganically modified clay to adsorb dioxins. However, most clays have an electric charge, so due to organic or inorganic modification, they have a positive charge, while humic acid has a negative charge. The mutual attraction of positive and negative charges creates a humic acid-clay complex, which allows the humic acid to adhere to the surface and internal voids of the clay, improving its hydrophobicity. At the same time, the humic acid also changes the surface charge of the clay, improving the dioxin adsorption efficiency of the humic acid-clay complex.

[0005] However, humic acid is sensitive to pH and is highly soluble in neutral and alkaline environments, which reduces its adsorption effect on dioxins. Modification of humic acid with clay reduces its solubility in neutral and alkaline environments and can increase its adsorption effect on dioxins, but the effect is not desirable. Summary of the Invention

[0006] The object of the present invention is to overcome the defects and shortcomings of the prior art, to provide a silicon-based adsorbent that has excellent adsorption performance for dioxins, can maintain good mechanical properties even in alkaline and neutral environments, effectively solves the problem that humic acid is highly soluble in neutral and alkaline environments, expands the application range of adsorbents, and can effectively improve the adsorption rate for dioxins.

[0007] The object of the present invention is to provide a silicon-based adsorbent, which has a polymer-modified composite clay substrate and supports humic acid on the surface, the composite clay being a combination of palygorskite, chlorite and illite, and the polymer obtained by polymerizing 4'-vinyl-4-biphenylcarboxylic acid monomer.

[0008] In some embodiments of the present invention, the mass ratio of the palygorskite to the chlorite to the 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 producing the above silicon-based adsorbent, the method comprising the steps of: S1. Under the protection of nitrogen gas, mix 4'-vinyl-4-biphenylcarboxylic acid with water, add sodium hydroxide, then add composite clay, heat, add initiator, continue to heat, react to obtain polymer modified composite clay; S2. Add dilute sulfuric acid to the polymer-modified composite clay to activate it, then add potassium humate aqueous solution to react and post-treat to obtain a silicon-based adsorbent.

[0011] In some embodiments of the present invention, in S1, the mass ratio of the 4'-vinyl-4-biphenylcarboxylic acid, sodium hydroxide, and initiator is 60-80:10-20:1.

[0012] In some embodiments of the present invention, in S1, the initiator is at least one selected from ammonium persulfate, sodium persulfate, and potassium persulfate.

[0013] In some embodiments of the present invention, in S1, the temperature of the heating is 50°C-70°C, and the time is 20 min-40 min.

[0014] In some embodiments of the present invention, in step S1, the temperature of the continuously elevated reaction is 80° C.-100° C., and the time is 4 hours-6 hours.

[0015] In some embodiments of the present invention, in S2, the mass ratio of the polymer-modified composite clay to dilute sulfuric acid to potassium humate solution is 1:8-12:1.5-2.5.

[0016] In some embodiments of the present invention, in S2, the activation temperature is 20°C-30°C and the activation time is 20 min-40 min.

[0017] In some embodiments of the present invention, in S2, the reaction temperature is 20°C-30°C and the reaction time is 50 min-70 min.

[0018] In some embodiments of the present invention, in S2, the mass concentration of the dilute sulfuric acid is 10%-20%.

[0019] In some embodiments of the present invention, in S2, the mass concentration of the potassium humate aqueous solution is 4%-6%.

[0020] Another object of the present invention is to provide an application of the silicon-based adsorbent or the silicon-based adsorbent produced by the method for producing the silicon-based adsorbent in treating exhaust gas from incineration of food waste.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 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 effect 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, and the positive and negative charges attract each other, enhancing the interaction force between the composite clay and humic acid, and the polymer and the composite clay interact with humic acid, which allows humic acid to maintain good mechanical properties in both alkaline and neutral environments, effectively solving the problem that humic acid is highly soluble in neutral and alkaline environments, and improving the adsorption rate of dioxin. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to fully understand the objectives, features, and advantages of the present invention, the concept and resulting technical effects of the present invention will be clearly and completely explained below with reference to examples. Obviously, the described examples are only some of the examples of the present invention, and not all of the examples. Other examples obtained by those skilled in the art based on the examples of the present invention without creative effort are also within the scope of protection of the present invention. Unless otherwise specified, the test methods used in the examples are conventional methods, and the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0023] Example 1 This embodiment provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, mix 60 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid with 360 parts by weight of water, add 20 parts by weight of sodium hydroxide, and then add a mixture of 48 parts by weight of palygorskite, 24 parts by weight of chlorite and 48 parts by weight of illite, heat to 70 ° C, maintain for 20 minutes, add 1 part by weight of ammonium persulfate, heat to 80 ° C, and continue reacting for 6 hours, wash the product with ethanol three times, dry and pulverize to obtain a polymer-modified composite clay; S2. Add 80 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, and activate at 20°C for 40 minutes, and then add 15 parts by weight of potassium humate aqueous solution, and react at 30°C for 50 minutes, and then filter, wash the filtration residue with deionized water three times, adjust the pH to 10, dry and grind, and obtain a silicon-based adsorbent.

[0024] Example 2 This embodiment provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, mix 80 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid with 500 parts by weight of water, add 10 parts by weight of sodium hydroxide, and then add a mixture of 120 parts by weight of palygorskite, 40 parts by weight of chlorite and 160 parts by weight of illite, heat to 50 ° C, maintain for 40 minutes, add 1 part by weight of sodium persulfate, heat to 100 ° C, continue reacting for 4 hours, wash the product with ethanol three times, dry and pulverize to obtain a polymer-modified composite clay; S2. Add 120 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, and activate the dilute sulfuric acid at 30°C for 20 minutes. Add 25 parts by weight of potassium humate aqueous solution, and react at 20°C for 70 minutes. The potassium humate aqueous solution has a mass concentration of 4%. Filter the residue, wash it with deionized water three times, adjust the pH to 10, dry and grind it, and obtain a silicon-based adsorbent.

[0025] Example 3 This embodiment provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, mix 70 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid with 500 parts by weight of water, add 15 parts by weight of sodium hydroxide, and then add a mixture of 70 parts by weight of palygorskite, 70 parts by weight of chlorite and 70 parts by weight of illite, heat to 60 ° C, maintain for 30 minutes, add 1 part by weight of potassium persulfate, heat to 90 ° C, and continue reacting for 5 hours, wash the product with ethanol three times, dry and pulverize to obtain a polymer-modified composite clay; S2. Add 100 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, the mass concentration of the dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes; further add 20 parts by weight of potassium humate aqueous solution, the mass concentration of the potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes; filter; wash the filtration residue with deionized water three times, adjust the pH value to 10, dry and pulverize to obtain a silicon-based adsorbent.

[0026] Comparative Example 1 This comparative example provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, 70 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid is mixed with 500 parts by weight of water, 15 parts by weight of sodium hydroxide is added, and 210 parts by weight of palygorskite is further added. The mixture is heated to 60°C, maintained for 30 minutes, 1 part by weight of potassium persulfate is added, the mixture is heated to 90°C, and reacted for 5 hours. The product is washed with ethanol three times, dried, and pulverized to obtain a polymer-modified composite clay. S2. Add 100 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, the mass concentration of the dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes; further add 20 parts by weight of potassium humate aqueous solution, the mass concentration of the potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes; filter; wash the filtration residue with deionized water three times, adjust the pH value to 10, dry and pulverize to obtain a silicon-based adsorbent.

[0027] Comparative Example 2 This comparative example provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, 70 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid is mixed with 500 parts by weight of water, 15 parts by weight of sodium hydroxide is added, and 210 parts by weight of chlorite is further added, the temperature is raised to 60°C, and the mixture is maintained for 30 minutes, 1 part by weight of potassium persulfate is added, the temperature is raised to 90°C, and the mixture is reacted for 5 hours, and the product is washed with ethanol three times, dried and pulverized to obtain a polymer-modified composite clay; S2. Add 100 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, the mass concentration of the dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes; further add 20 parts by weight of potassium humate aqueous solution, the mass concentration of the potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes; filter; wash the filtration residue with deionized water three times, adjust the pH value to 10, dry and pulverize to obtain a silicon-based adsorbent.

[0028] Comparative Example 3 This comparative example provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, 70 parts by weight of 4'-vinyl-4-biphenylcarboxylic acid is mixed with 500 parts by weight of water, 15 parts by weight of sodium hydroxide is added, and 210 parts by weight of illite is added. The mixture is heated to 60°C, maintained for 30 minutes, 1 part by weight of potassium persulfate is added, the mixture is heated to 90°C, and reacted for 5 hours. The product is washed with ethanol three times, dried, and pulverized to obtain a polymer-modified composite clay. S2. Add 100 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, the mass concentration of the dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes; further add 20 parts by weight of potassium humate aqueous solution, the mass concentration of the potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes; filter; wash the filtration residue with deionized water three times, adjust the pH value to 10, dry and pulverize to obtain a silicon-based adsorbent.

[0029] Comparative Example 4 This comparative example provides a silicon-based adsorbent, the manufacturing method of which is as follows: S1. Under the protection of nitrogen gas, add 15 parts by weight of sodium hydroxide to 500 parts by weight of water, and then add a mixture of 70 parts by weight of palygorskite, 70 parts by weight of chlorite and 70 parts by weight of illite, heat to 60 ° C, keep for 30 minutes, add 1 part by weight of potassium persulfate, heat to 90 ° C and continue reacting for 5 hours, wash the product with ethanol three times, dry and grind to obtain a polymer-modified composite clay; S2. Add 100 parts by weight of dilute sulfuric acid to 10 parts by weight of polymer-modified composite clay, the mass concentration of the dilute sulfuric acid is 15%, and activate at 25°C for 30 minutes; further add 20 parts by weight of potassium humate aqueous solution, the mass concentration of the potassium humate aqueous solution is 5%, and react at 25°C for 60 minutes; filter; wash the filtration residue with deionized water three times, adjust the pH value to 10, dry and pulverize to obtain a silicon-based adsorbent.

[0030] The silicon-based adsorbents of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The test methods are as follows, and the results are shown in Table 1.

[0031] The silicon-based adsorbents produced in Examples 1-3 and Comparative Examples 1-4 were used to adsorb dioxins. Exhaust gas purification was carried out at a food waste incineration plant using the "SNCR + semi-dry deoxidation + flue silicon-based adsorbent injection + bag-type dust removal" method. The silicon-based adsorbents produced in Examples 1-3 and Comparative Examples 1-4 were added at 0.40 kg / t waste, 0.50 kg / t waste, and 0.60 kg / t waste, respectively. Dioxins were detected before and after the exhaust gas purification treatment according to the method described in "Measurement of dioxins in ambient air and exhaust gas: 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. JPEG0007804141000001.jpg145170

[0032] As can be seen from Table 1, all of the silicon-based adsorbents prepared in Examples 1 to 3 of the present invention can effectively remove dioxins. On the other hand, the silicon-based adsorbent prepared in Examples 1-3 of the present invention contains poly(4'-vinyl-4-biphenylcarboxylic acid), which creates a conjugation effect between the molecular structure of the silicon-based adsorbent and 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 humic acid has a negative charge. The positive and negative charges attract each other, enhancing the interaction between the composite clay and humic acid. The polymer and the composite clay interact with humic acid, allowing humic acid to maintain good mechanical properties in both alkaline and neutral environments, effectively solving the problem of humic acid being highly soluble in neutral and alkaline environments and improving the dioxin adsorption rate. The silicon-based adsorbent prepared in Comparative Examples 1-4 contains only clay or does not contain poly(4'-vinyl-4-biphenylcarboxylic acid), which improves the solubility of humic acid in the silicon-based adsorbent in neutral and alkaline environments and further reduces the dioxin adsorption rate of the silicon-based adsorbent.

[0033] The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples. Any other changes, modifications, substitutions, combinations, and simplifications within the scope of the spirit and principles of the present invention are all equivalent substitution forms and fall within the protection scope of the present invention.

Claims

1. A silicon-based adsorbent, The silicon-based adsorbent has a polymer-modified composite clay base and humic acid supported on the surface, the composite clay being a combination of palygorskite, chlorite, and illite, and the polymer is obtained by polymerizing 4'-vinyl-4-biphenylcarboxylic acid monomer.

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

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

4. A method for producing the silicon-based adsorbent according to claim 1, S1. Under the protection of nitrogen gas, mix 4'-vinyl-4-biphenylcarboxylic acid with water, add sodium hydroxide, add composite clay, heat, add initiator, continue to heat, react to obtain polymer modified composite clay; S2. Add dilute sulfuric acid to polymer-modified composite clay to activate it, then add potassium humate aqueous solution to react and post-treat to obtain a silicon-based adsorbent; A method for producing a silicon-based adsorbent, comprising:

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

1.

6. 5. The method for producing a silicon-based adsorbent according to claim 4, wherein in step S1, the initiator is at least one selected from the group consisting of ammonium persulfate, sodium persulfate, and potassium persulfate.

7. In S1, the temperature of the temperature rise is 50°C-70°C, and the time is 20 min-40 min; 5. The method for producing a silicon-based adsorbent according to claim 4, wherein the temperature during the continuous temperature increase is 80° C. to 100° C., and the reaction time is 4 hours to 6 hours.

8. In S2, the mass ratio of the polymer-modified composite clay to dilute sulfuric acid to potassium humate aqueous solution is 1:8-12:1.5-2.5; The activation temperature is 20°C-30°C, and the activation time is 20-40 min.

5. The method for producing a silicon-based adsorbent according to claim 4, wherein the reaction temperature is 20° C. to 30° C. and the reaction time is 50 min to 70 min.

9. In S2, the mass concentration of the potassium humate aqueous solution is 4%-6%, 5. The method for producing a silicon-based adsorbent according to claim 4, wherein the mass concentration of the dilute sulfuric acid is 10% to 20%.

10. A method for treating exhaust gas from incineration of food waste, using the silicon-based adsorbent according to any one of claims 1 to 3 or the silicon-based adsorbent produced by the method for producing a silicon-based adsorbent according to any one of claims 4 to 9.

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