A sewage treatment agent after pyrolysis of waste tires and its preparation method

Abstract

The present invention relates to the technical field of sewage treatment, and discloses a sewage treatment agent after pyrolysis of waste tires and a preparation method thereof. In the present invention, polyferric silicate sulfate, polyaluminum chloride, thiourea-based sulfobetaine modified chitosan, and imidazoline quaternary ammonium salt modified graphene oxide are mixed to obtain a sewage treatment agent after pyrolysis of waste tires. Sulfur and amino groups in the thiourea group can form stable multidentate coordination complexes with heavy metal ions to achieve efficient adsorption; by introducing thiourea groups and sulfobetaine structures onto the chitosan molecular chain, the adsorption sites of chitosan are increased, and the sewage treatment effect is improved; the nitrogen atom on the imidazoline ring can form hydrogen bonds during the flocculation process, enhancing the interaction between the sewage treatment agent and colloidal particles and promoting the aggregation of colloidal particles; by introducing imidazoline quaternary ammonium salts into graphene oxide, the agglomeration of graphene oxide sheets is reduced, further improving the sewage treatment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and specifically relates to a sewage treatment agent after pyrolysis of waste tires and a preparation method thereof. Background Art

[0002] With the rapid development of the automotive industry, the large-scale treatment of waste tires has become a global environmental protection problem. The pyrolysis technology has attracted much attention because it can realize the resource utilization of tires. However, the pyrolysis wastewater generated in the production process has complex components, containing harmful components such as organic matter, inorganic salts, heavy metals, polycyclic aromatic hydrocarbons, and oil substances, and has characteristics such as high toxicity and poor biodegradability. If directly discharged without effective treatment, it will pose a serious threat to the water ecosystem and human health. Patent CN104478097A discloses a water purifying agent for sewage generated in the recycling of waste tires and a sewage treatment method. The water purifying agent for sewage treatment in this invention has high safety and does not cause secondary pollution. Using a material with adsorption ability as the raw material, supplemented by microorganisms to treat sewage, it has a wide range of uses and can be recycled, but its treatment effect on pyrolysis sewage of waste tires still needs to be improved. Summary of the Invention

[0003] (I) Technical Problems to be Solved

[0004] Aiming at the deficiencies of the prior art, the present invention provides a sewage treatment agent after pyrolysis of waste tires and a preparation method thereof, which has a good treatment effect on the sewage after pyrolysis of waste tires.

[0005] (II) Technical Solutions

[0006] To achieve the above object, the present invention provides the following technical solutions: A sewage treatment agent after pyrolysis of waste tires, comprising the following weight components: 4.5 - 7.5 parts by weight of polysilferric sulfate, 10 - 18 parts by weight of polyaluminum chloride, 4 - 8 parts by weight of thiourea-based sulfobetaine modified chitosan, and 1.2 - 1.8 parts by weight of imidazoline quaternary ammonium salt modified graphene oxide.

[0007] Preferably, the preparation method of the thiourea-based sulfobetaine modified chitosan includes the following steps:

[0008] (1) Add 3 - 3.2 g of 1,3 - propane sultone to 40 - 60 mL of acetone solvent, stir and dissolve at 30 - 35 °C. Dissolve 4.4 - 4.6 g of [3 - (dimethylamino)propyl]thiourea in 60 - 80 mL of acetone solvent, and drop it into the 1,3 - propane sultone solution. After dropping, raise the temperature to the reaction temperature and react for 2.5 - 3.5 h. After the reaction, filter under reduced pressure and dry to obtain thiourea-based sulfobetaine;

[0009] (2) Add 15 - 25 mL of glacial acetic acid and 80 - 100 mL of deionized water to the reactor. Add 1.3 - 1.8 g of chitosan and 1.4 - 1.6 g of thiourea-based sulfobetaine thereto, stir and mix. Dropwise add 1.8 - 2.2 mL of formaldehyde solution thereto, react at 24 - 30 °C for 10 - 14 h. After the reaction is completed, adjust the pH to 7.5 - 8 with a sodium hydroxide solution with a mass fraction of 4% - 8%. Wash the precipitate and then filter it under reduced pressure, and dry it in vacuum to obtain thiourea-based sulfobetaine modified chitosan.

[0010] Preferably, in the step (1), the reaction temperature is 38 - 44 °C.

[0011] Preferably, in the step (2), the mass fraction of the formaldehyde solution is 37% - 38%.

[0012] Preferably, the preparation method of the imidazoline quaternary ammonium salt modified graphene oxide includes the following steps:

[0013] S1. Add 3.7 - 4.3 g of lauric acid to the reactor, heat up to 160 - 170 °C, add 1.8 - 2.4 mL of water-carrying agent and 4.8 - 5.2 g of triethylenetetramine thereto. After refluxing for 2 - 3 h, heat up to 220 - 230 °C and continue to react for 3.5 - 4 h. After the reaction is completed, distill under reduced pressure to obtain lauric acid imidazoline intermediate.

[0014] S2. Add 4.6 - 5.2 g of lauric acid imidazoline intermediate to 50 - 80 mL of anhydrous ethanol solvent, stir to dissolve it. Add 1.8 - 2.2 g of benzyl chloride thereto, heat up to 50 - 65 °C and react for 7 - 10 h. After the reaction is completed, rotary evaporate to remove the solvent, recrystallize and then dry it in vacuum to obtain lauric acid imidazoline quaternary ammonium salt.

[0015] S3. Add 1.2 - 1.8 g of graphene oxide to 180 - 200 mL of deionized water, ultrasonically disperse for 40 - 50 min, adjust the pH to 5.5 - 6 with a potassium hydroxide solution with a mass fraction of 1.5% - 2%. Add 0.5 - 0.9 g of condensing agent and react for 1 - 1.5 h, then add 1.3 - 1.4 g of lauric acid imidazoline quaternary ammonium salt, introduce nitrogen for protection, heat up to 65 - 75 °C and react for 7 - 10 h. After the reaction is completed, centrifuge, wash and dry it in vacuum to obtain imidazoline quaternary ammonium salt modified graphene.

[0016] Preferably, the water-carrying agent in S1 is xylene.

[0017] Preferably, the condensing agent in S3 is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

[0018] Preferably, the preparation method of the sewage treatment agent after pyrolysis of waste tires is as follows: Add polyferric silicate sulfate, polyaluminum chloride, thiourea-based sulfobetaine modified chitosan, and imidazoline quaternary ammonium salt modified graphene oxide into a mixer, and mix at 200 - 400 rpm for 10 - 15 minutes to obtain the sewage treatment agent after pyrolysis of waste tires.

[0019] (III) Beneficial technical effects

[0020] In the present invention, a sewage treatment agent after pyrolysis of waste tires is obtained by mixing polyferric silicate sulfate, polyaluminum chloride, thiourea-based sulfobetaine modified chitosan, and imidazoline quaternary ammonium salt modified graphene oxide.

[0021] Sulfur and amino groups in the thiourea group have strong coordination ability and can form stable multidentate coordination complexes with heavy metal ions to achieve efficient adsorption; the sulfonic acid group is a strong anionic group and can undergo electrostatic attraction with positively charged metal ions or positively charged colloidal particles in sewage to promote flocculation precipitation; many particles in sewage carry negative charges, and the positive charges carried by quaternary ammonium salt cations can neutralize these negative charges, thereby reducing the electrostatic repulsion between particles and making it easier for particles to approach and aggregate with each other to form larger flocs; by introducing thiourea groups and sulfobetaine structures onto the chitosan molecular chain, the adsorption sites of chitosan are increased and the sewage treatment effect is improved; the nitrogen atom on the imidazoline ring can form hydrogen bonds during the flocculation process, and this hydrogen bond effect helps to enhance the interaction between the sewage treatment agent and colloidal particles, enabling it to better adsorb on the surface of colloidal particles and promoting the aggregation between colloidal particles; by introducing imidazoline quaternary ammonium salt into graphene oxide, the distance between graphene oxide sheets is enlarged, the mutual attraction between sheets is weakened, the aggregation of sheets is reduced, the dispersion of graphene oxide in sewage is promoted, and the sewage treatment effect is further improved. Description of the drawings

[0022] Figure 1 is the synthesis reaction formula of thiourea-based sulfobetaine modified chitosan.

[0023] Figure 2 is the synthesis reaction formula of lauric acid imidazoline quaternary ammonium salt. Specific embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments. Example 1

[0026] (1) Add 3 g of 1,3-propane sultone to 40 mL of acetone solvent, stir and dissolve at 30 °C. Dissolve 4.4 g of [3-(dimethylamino)propyl]thiourea in 60 mL of acetone solvent, and drop it into the 1,3-propane sultone solution. After the dropping is completed, raise the temperature to 38 °C and react for 2.5 h. After the reaction is completed, filter under reduced pressure and dry to obtain thiourea-based sulfobetaine.

[0027] (2) Add 15 mL of glacial acetic acid and 80 mL of deionized water to the reactor. Add 1.3 g of chitosan and 1.4 g of thiourea-based sulfobetaine, stir and mix. Drop 1.8 mL of formaldehyde solution with a mass fraction of 37% into it, and react at 24 °C for 10 h. After the reaction is completed, adjust the pH to 7.5 with a sodium hydroxide solution with a mass fraction of 4%. Wash the precipitate, filter under reduced pressure, and dry in vacuum to obtain thiourea-based sulfobetaine-modified chitosan.

[0028] (3) Add 3.7 g of lauric acid to the reactor, raise the temperature to 160 °C, add 1.8 mL of xylene water-carrying agent and 4.8 g of triethylenetetramine to it. After refluxing for 2 h, raise the temperature to 220 °C and continue to react for 3.5 h. After the reaction is completed, distill under reduced pressure to obtain lauric acid imidazoline intermediate.

[0029] (4) Add 4.6 g of lauric acid imidazoline intermediate to 50 mL of anhydrous ethanol solvent, stir and dissolve it. Add 1.8 g of benzyl chloride to it, raise the temperature to 50 °C and react for 7 h. After the reaction is completed, rotary evaporate to remove the solvent, recrystallize and dry in vacuum to obtain lauric acid imidazoline quaternary ammonium salt.

[0030] (5) Add 1.2 g of graphene oxide to 180 mL of deionized water, ultrasonically disperse for 40 min, adjust the pH to 5.5 with a potassium hydroxide solution with a mass fraction of 1.5%. Add 0.5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide condensing agent and react for 1 h, then add 1.3 g of lauric acid imidazoline quaternary ammonium salt, pass in nitrogen for protection, raise the temperature to 65 °C and react for 7 h. After the reaction is completed, centrifuge, wash and dry in vacuum to obtain imidazoline quaternary ammonium salt-modified graphene.

[0031] (6) Add 4.5 parts by weight of polysilicon ferric sulfate, 10 parts by weight of polyaluminum chloride, 4 parts by weight of thiourea-based sulfobetaine-modified chitosan, and 1.2 parts by weight of imidazoline quaternary ammonium salt-modified graphene oxide to the mixer, and mix at 200 rpm for 10 min to obtain a sewage treatment agent for the pyrolysis of waste tires. Example 2

[0032] (1) 3.2 g of 1,3 - propane sultone was added to 60 mL of acetone solvent and stirred to dissolve at 35°C. 4.6 g of [3 - (dimethylamino)propyl]thiourea was dissolved in 80 mL of acetone solvent and added dropwise to the 1,3 - propane sultone solution. After the addition was complete, the temperature was raised to 44°C and the reaction was carried out for 3.5 h. After the reaction ended, filtration was carried out under reduced pressure and dried to obtain thiourea - based sulfobetaine;

[0033] (2) 25 mL of glacial acetic acid and 100 mL of deionized water were added to a reactor, and 1.8 g of chitosan and 1.6 g of thiourea - based sulfobetaine were added thereto and stirred and mixed. 2.2 mL of a 38% formaldehyde solution by mass was added dropwise thereto, and the reaction was carried out at 30°C for 14 h. After the reaction ended, the pH was adjusted to 8 with an 8% sodium hydroxide solution by mass, the precipitate was washed and then filtered under reduced pressure, and dried in vacuo to obtain thiourea - based sulfobetaine - modified chitosan;

[0034] (3) 4.3 g of lauric acid was added to a reactor, the temperature was raised to 170°C, 2.4 mL of xylene water - carrying agent and 5.2 g of triethylenetetramine were added thereto, and after refluxing for 3 h, the temperature was raised to 230°C and the reaction was continued for 4 h. After the reaction ended, distillation was carried out under reduced pressure to obtain a lauric acid imidazoline intermediate;

[0035] (4) 5.2 g of lauric acid imidazoline intermediate was added to 80 mL of anhydrous ethanol solvent and stirred to dissolve. 2.2 g of benzyl chloride was added thereto, and the temperature was raised to 65°C and the reaction was carried out for 10 h. After the reaction ended, the solvent was removed by rotary evaporation, and after recrystallization, it was dried in vacuo to obtain lauric acid imidazoline quaternary ammonium salt;

[0036] (5) 1.8 g of graphene oxide was added to 200 mL of deionized water, ultrasonically dispersed for 50 min, the pH was adjusted to 6 with a 2% potassium hydroxide solution by mass, 0.9 g of 1 - (3 - dimethylaminopropyl)-3 - ethylcarbodiimide condensing agent was added thereto and reacted for 1.5 h, then 1.4 g of lauric acid imidazoline quaternary ammonium salt was added, nitrogen was introduced for protection, the temperature was raised to 75°C and the reaction was carried out for 10 h. After the reaction ended, centrifugation and washing were carried out and dried in vacuo to obtain imidazoline quaternary ammonium salt - modified graphene;

[0037] (6) 7.5 parts by weight of poly - silicic acid iron, 18 parts by weight of polyaluminum chloride, 8 parts by weight of thiourea - based sulfobetaine - modified chitosan, and 1.8 parts by weight of imidazoline quaternary ammonium salt - modified graphene oxide were added to a mixer and mixed at 400 rpm for 15 min to obtain a sewage treatment agent for the pyrolysis of waste tires. Example 3

[0038] (1) Add 3.1 g of 1,3 - propane sultone to 50 mL of acetone solvent, stir and dissolve it at 32 °C. Dissolve 4.5 g of [3 - (dimethylamino)propyl]thiourea in 70 mL of acetone solvent, and drop it into the 1,3 - propane sultone solution. After the dropping is completed, raise the temperature to 41 °C and react for 3 h. After the reaction is completed, filter under reduced pressure and dry to obtain thiourea - based sulfobetaine;

[0039] (2) Add 20 mL of glacial acetic acid and 90 mL of deionized water to the reactor. Add 1.55 g of chitosan and 1.5 g of thiourea - based sulfobetaine to it, stir and mix. Drop 2 mL of formaldehyde solution with a mass fraction of 37.5% into it, and react at 27 °C for 12 h. After the reaction is completed, adjust the pH to 7.8 with 6% sodium hydroxide solution. Wash the precipitate, filter under reduced pressure, and dry in vacuum to obtain thiourea - based sulfobetaine - modified chitosan;

[0040] (3) Add 4 g of lauric acid to the reactor, raise the temperature to 165 °C, add 2.1 mL of xylene water - carrying agent and 5 g of triethylenetetramine to it. After refluxing and reacting for 2.5 h, raise the temperature to 225 °C and continue to react for 3.8 h. After the reaction is completed, distill under reduced pressure to obtain lauric acid imidazoline intermediate;

[0041] (4) Add 4.9 g of lauric acid imidazoline intermediate to 65 mL of anhydrous ethanol solvent, stir and dissolve it. Add 2 g of benzyl chloride to it, raise the temperature to 58 °C and react for 8.5 h. After the reaction is completed, remove the solvent by rotary evaporation, recrystallize and dry in vacuum to obtain lauric acid imidazoline quaternary ammonium salt;

[0042] (5) Add 1.5 g of graphene oxide to 190 mL of deionized water, ultrasonically disperse it for 45 min, adjust the pH to 5.7 with 1.7% potassium hydroxide solution. Add 0.7 g of 1 - (3 - dimethylaminopropyl)-3 - ethylcarbodiimide condensing agent and react for 1.2 h, then add 1.35 g of lauric acid imidazoline quaternary ammonium salt, introduce nitrogen protection, raise the temperature to 70 °C and react for 8.5 h. After the reaction is completed, centrifuge, wash and dry in vacuum to obtain imidazoline quaternary ammonium salt - modified graphene;

[0043] (6) Add 6 parts by weight of polysilicon ferric sulfate, 14 parts by weight of polyaluminum chloride, 6 parts by weight of thiourea - based sulfobetaine - modified chitosan, and 1.5 parts by weight of imidazoline quaternary ammonium salt - modified graphene oxide to the mixer, and mix at 300 rpm for 12 min to obtain the sewage treatment agent for waste tire pyrolysis. Example 4

[0044] (1) Add 3 g of 1,3 - propane sultone to 40 mL of acetone solvent, stir and dissolve it at 30 °C. Dissolve 4.4 g of [3 - (dimethylamino)propyl]thiourea in 60 mL of acetone solvent, and drop it into the 1,3 - propane sultone solution. After the dropping is completed, raise the temperature to 38 °C and react for 2.5 h. After the reaction is completed, filter under reduced pressure and dry to obtain thiourea - based sulfobetaine;

[0045] (2) Add 15 mL of glacial acetic acid and 80 mL of deionized water to the reactor. Add 1.3 g of chitosan and 1.4 g of thiourea - based sulfobetaine, stir and mix. Drop 1.8 mL of 37% formaldehyde solution into it, and react at 24 °C for 10 h. After the reaction is completed, adjust the pH to 7.5 with 4% sodium hydroxide solution. Wash the precipitate, filter under reduced pressure, and dry in vacuum to obtain thiourea - based sulfobetaine - modified chitosan;

[0046] (3) Add 4.3 g of lauric acid to the reactor, raise the temperature to 170 °C, add 2.4 mL of xylene water - carrying agent and 5.2 g of triethylenetetramine, reflux and react for 3 h, then raise the temperature to 230 °C and continue to react for 4 h. After the reaction is completed, distill under reduced pressure to obtain lauric acid imidazoline intermediate;

[0047] (4) Add 5.2 g of lauric acid imidazoline intermediate to 80 mL of anhydrous ethanol solvent, stir and dissolve it. Add 2.2 g of benzyl chloride to it, raise the temperature to 65 °C and react for 10 h. After the reaction is completed, remove the solvent by rotary evaporation, recrystallize and dry in vacuum to obtain lauric acid imidazoline quaternary ammonium salt;

[0048] (5) Add 1.5 g of graphene oxide to 190 mL of deionized water, ultrasonically disperse it for 45 min, adjust the pH to 5.7 with 1.7% potassium hydroxide solution. Add 0.7 g of 1 - (3 - dimethylaminopropyl)-3 - ethylcarbodiimide condensing agent and react for 1.2 h, then add 1.35 g of lauric acid imidazoline quaternary ammonium salt, introduce nitrogen protection, raise the temperature to 70 °C and react for 8.5 h. After the reaction is completed, centrifuge, wash and dry in vacuum to obtain imidazoline quaternary ammonium salt - modified graphene;

[0049] (6) Add 6 parts by weight of polysilicon ferric sulfate, 14 parts by weight of polyaluminum chloride, 6 parts by weight of thiourea - based sulfobetaine - modified chitosan, and 1.5 parts by weight of imidazoline quaternary ammonium salt - modified graphene oxide to the mixer, and mix at 300 rpm for 12 min to obtain the sewage treatment agent for the pyrolysis of waste tires. Example 5

[0050] (1) Add 3.2 g of 1,3 - propane sultone to 60 mL of acetone solvent, stir and dissolve at 35 °C. Dissolve 4.6 g of [3 - (dimethylamino)propyl]thiourea in 80 mL of acetone solvent, and add it dropwise to the 1,3 - propane sultone solution. After the addition is complete, raise the temperature to 44 °C and react for 3.5 h. After the reaction is completed, filter under reduced pressure and dry to obtain thiourea - based sulfobetaine;

[0051] (2) Add 25 mL of glacial acetic acid and 100 mL of deionized water to the reactor, add 1.8 g of chitosan and 1.6 g of thiourea - based sulfobetaine, stir and mix. Add 2.2 mL of 38% formaldehyde solution dropwise thereto, and react at 30 °C for 14 h. After the reaction is completed, adjust the pH to 8 with 8% sodium hydroxide solution, wash the precipitate, filter under reduced pressure, and dry in vacuum to obtain thiourea - based sulfobetaine - modified chitosan;

[0052] (3) Add 4 g of lauric acid to the reactor, raise the temperature to 165 °C, add 2.1 mL of xylene water - carrying agent and 5 g of triethylenetetramine, reflux and react for 2.5 h, then raise the temperature to 225 °C and continue to react for 3.8 h. After the reaction is completed, distill under reduced pressure to obtain lauric acid imidazoline intermediate;

[0053] (4) Add 4.9 g of lauric acid imidazoline intermediate to 65 mL of anhydrous ethanol solvent, stir and dissolve, add 2 g of benzyl chloride thereto, raise the temperature to 58 °C and react for 8.5 h. After the reaction is completed, remove the solvent by rotary evaporation, recrystallize and dry in vacuum to obtain lauric acid imidazoline quaternary ammonium salt;

[0054] (5) Add 1.2 g of graphene oxide to 180 mL of deionized water, ultrasonically disperse for 40 min, adjust the pH to 5.5 with 1.5% potassium hydroxide solution, add 0.5 g of 1 - (3 - dimethylaminopropyl) - 3 - ethylcarbodiimide condensing agent and react for 1 h, then add 1.3 g of lauric acid imidazoline quaternary ammonium salt, introduce nitrogen protection, raise the temperature to 65 °C and react for 7 h. After the reaction is completed, centrifuge, wash and dry in vacuum to obtain imidazoline quaternary ammonium salt - modified graphene;

[0055] (6) Add 4.5 parts by weight of polysilicon ferric sulfate, 10 parts by weight of polyaluminum chloride, 4 parts by weight of thiourea - based sulfobetaine - modified chitosan, and 1.2 parts by weight of imidazoline quaternary ammonium salt - modified graphene oxide to the mixer, and mix at 200 rpm for 10 min to obtain a sewage treatment agent for the pyrolysis of waste tires.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 1 is that the thiourea - based sulfobetaine - modified chitosan is not contained in step (6).

[0058] Comparative Example 2

[0059] Compared with Example 1, the difference in this comparative example lies in that imidazoline quaternary ammonium salt modified graphene oxide is used in step (6).

[0060] Pour 1 L of the wastewater after pyrolysis of waste tires into a beaker, add a predetermined amount of the sewage treatment agent, set the stirrer at 200 r / min, stir rapidly for 2 min, adjust to 50 r / min, and stir slowly for 15 min. After sedimentation for 40 min, take the supernatant, measure the COD and turbidity, compare the measurement results with the initial data, calculate the COD removal rate and the turbidity removal rate; the test results are shown in Table 1; use an atomic absorption spectrophotometer to measure Cd 2+ , Pb 2+ , Zn 2+ concentration, compare the measurement results with the initial data, and calculate the Cd 2+ , Pb 2+ , Zn 2 + removal rate, and the test results are shown in Table 2. The dosage of the sewage treatment agent is 30 mg / L.

[0061] Table 1: Test of COD removal rate and turbidity removal rate.

[0062] Item COD Removal Rate (%) Turbidity Removal Rate (%) Example 1 99.8 95.4 Example 2 99.6 93.8 Example 3 98.5 95.2 Example 4 99.7 94.5 Example 5 99.4 95.0 Comparative Example 1 90.2 87.2 Comparative Example 2 92.8 89.3

[0063] Table 2: Test of Cd 2+ , Pb 2+ , Zn 2+ removal rate test.

[0064] Item <![CDATA[Cd 2+ Removal rate (%)]]> <![CDATA[Pb 2+ Removal rate (%)]]> <![CDATA[Zn 2+ Removal rate (%)]]> Example 1 98.2 97.3 97.2 Example 2 97.6 96.7 96.2 Example 3 97.9 96.9 96.5 Example 4 98.0 97.0 96.8 Example 5 98.4 97.5 97.4 Comparative Example 1 94.3 93.6 90.7 Comparative Example 2 88.7 86.8 86.0

[0065] As can be seen from Table 1 and Table 2, the sewage treatment agents in Examples 1-5 of the present invention have better treatment effects on the wastewater after pyrolysis of waste tires compared with the sewage treatment agents in Comparative Examples 1-2.

[0066] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0067] 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

[0068] Those skilled in the art should understand that the above are only several specific embodiments of the present invention, rather than all embodiments. It should be pointed out that many variations and improvements can be made for those of ordinary skill in the art, and all variations or improvements that do not exceed the scope described in the claims should be regarded as the protection scope of the present invention.

Claims

1. A sewage treatment agent after pyrolysis of waste tires, characterized in that, It includes the following weight components: 4.5 - 7.5 parts by weight of polysilicon ferric sulfate, 10 - 18 parts by weight of polyaluminum chloride, 4 - 8 parts by weight of thiourea-based sulfobetaine modified chitosan, and 1.2 - 1.8 parts by weight of imidazoline quaternary ammonium salt modified graphene oxide; The preparation method of the thiourea-based sulfobetaine modified chitosan, which includes the following steps: (1) Add 3 - 3.2 g of 1,3 - propane sultone to 40 - 60 mL of acetone solvent, stir and dissolve at 30 - 35 °C. Dissolve 4.4 - 4.6 g of [3-(dimethylamino)propyl]thiourea in 60 - 80 mL of acetone solvent, and drop it into the 1,3 - propane sultone solution. After dropping, raise the temperature to the reaction temperature and react for 2.5 - 3.5 h. After the reaction, filter under reduced pressure and dry to obtain thiourea-based sulfobetaine; (2) Add 15 - 25 mL of glacial acetic acid and 80 - 100 mL of deionized water to the reactor. Add 1.3 - 1.8 g of chitosan and 1.4 - 1.6 g of thiourea-based sulfobetaine, stir and mix. Drop 1.8 - 2.2 mL of formaldehyde solution into it, and react at 24 - 30 °C for 10 - 14 h. After the reaction, adjust the pH to 7.5 - 8 with a sodium hydroxide solution with a mass fraction of 4% - 8%. Wash the precipitate, filter under reduced pressure, and dry in vacuum to obtain thiourea-based sulfobetaine modified chitosan; The preparation method of the imidazoline quaternary ammonium salt modified graphene oxide, which includes the following steps: S1. Add 3.7 - 4.3 g of lauric acid to the reactor, raise the temperature to 160 - 170 °C, add 1.8 - 2.4 mL of water-carrying agent and 4.8 - 5.2 g of triethylenetetramine, reflux and react for 2 - 3 h, then raise the temperature to 220 - 230 °C and continue to react for 3.5 - 4 h. After the reaction, distill under reduced pressure to obtain lauric acid imidazoline intermediate; S2. Add 4.6 - 5.2 g of lauric acid imidazoline intermediate to 50 - 80 mL of anhydrous ethanol solvent, stir and dissolve. Add 1.8 - 2.2 g of benzyl chloride to it, raise the temperature to 50 - 65 °C and react for 7 - 10 h. After the reaction, remove the solvent by rotary evaporation, recrystallize and dry in vacuum to obtain lauric acid imidazoline quaternary ammonium salt; S3. Add 1.2 - 1.8 g of graphene oxide to 180 - 200 mL of deionized water, ultrasonically disperse for 40 - 50 min, adjust the pH to 5.5 - 6 with a potassium hydroxide solution with a mass fraction of 1.5% - 2%. Add 0.5 - 0.9 g of condensing agent and react for 1 - 1.5 h, then add 1.3 - 1.4 g of lauric acid imidazoline quaternary ammonium salt, introduce nitrogen protection, raise the temperature to 65 - 75 °C and react for 7 - 10 h. After the reaction, centrifuge, wash and dry in vacuum to obtain imidazoline quaternary ammonium salt modified graphene; 2. The sewage treatment agent after cracking of waste tires according to claim 1, characterized in that, The reaction temperature in the step (1) is 38 - 44 °C.

3. The sewage treatment agent after cracking of waste tires according to claim 1, characterized in that, The mass fraction of the formaldehyde solution in the step (2) is 37% - 38%.

4. The sewage treatment agent after pyrolysis of waste tires according to claim 1, wherein, The water-carrying agent in the S1 is xylene.

5. The sewage treatment agent after cracking of waste tires according to claim 1, wherein, The condensing agent in the S3 is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

6. A preparation method of a sewage treatment agent after pyrolysis of waste tires as described in any one of claims 1-5, characterized in that, The preparation method of the sewage treatment agent after pyrolysis of waste tires is as follows: Add polyferric silicate sulfate, polyaluminum chloride, thiourea-based sulfobetaine modified chitosan, and imidazoline quaternary ammonium salt modified graphene oxide into a mixer, and mix at 200 - 400 rpm for 10 - 15 min to obtain the sewage treatment agent after pyrolysis of waste tires.

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