A rinse agent, its preparation method and use

Abstract

The application discloses a kind of eluent and its preparation method and application, preparation method includes: adding potassium methoxide methanol solution to the trimethylolpropane in molten state, after stirring, vacuumizing, then droping glycidol monomer, after reaction, add methanol, dry, obtain hyperbranched polyglycerol ether;Add carbonyl imidazole to the N,N-dimethylformamide solution of saturated fatty acid, after stirring and mixing, drop to the N,N-dimethylformamide solution of hyperbranched polyglycerol ether, reaction is heated in nitrogen atmosphere, after reaction, the product is treated, obtain temperature-sensitive hyperbranched polyglycidol ether eluent.The eluent prepared in the application can greatly reduce the treatment cost of elution waste liquid while efficiently removing heavy metals.

Description

Technical Field

[0001] This invention belongs to the field of sludge pollution remediation technology, specifically relating to a leaching agent, its preparation method, and its application. Background Technology

[0002] With economic and social development, river water pollution is intensifying. Bottom sediment, as a crucial component of water bodies, contains a large concentration of pollutants, making it a major endogenous source of pollution for rivers and lakes. Disturbance of the water overlying the bottom sediment can lead to the secondary release of pollutants, resulting in repeated water pollution and even endangering terrestrial life and human health.

[0003] Heavy metal contamination is one of the most serious problems in sediment pollution, and there are two main remediation methods: solidification / stabilization and chemical leaching. Solidification / stabilization still has problems such as incomplete removal of heavy metals, requiring long-term monitoring. Leaching technology, on the other hand, is simple to implement, has high removal efficiency, and can achieve permanent removal of heavy metals. The key to leaching technology is the selection of the leaching agent. Currently, the most commonly used leaching agents include EDTA, EDDS, and organic acids, but all of these generate large amounts of leaching wastewater containing leaching agent-heavy metal compounds, increasing leaching costs and limiting the development of leaching technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rinsing agent, its preparation method and application. The prepared rinsing agent can greatly reduce the treatment cost of rinsing waste liquid while efficiently removing heavy metals.

[0005] This invention provides the following technical solution:

[0006] In a first aspect, a method for preparing a rinsing agent is provided, comprising the following steps:

[0007] A methanol solution of potassium methoxide was added to molten trimethylolpropane, stirred and then vacuumed. Glycidyl monomer was then added dropwise. After the reaction was complete, methanol was added and the mixture was dried to obtain hyperbranched polyglycerol ether.

[0008] Carbonyl imidazole (CDI) was added to a solution of N,N-dimethylformamide (DMF) containing saturated fatty acids and stirred until homogeneous. The mixture was then added dropwise to a solution of hyperbranched polyglycerol ether in DMF. The reaction was carried out under a nitrogen atmosphere and heated. The product was then post-treated to obtain a thermosensitive hyperbranched polyglycidyl ether eluent.

[0009] Furthermore, the trimethylolpropane is heated to 70-75°C in an oil bath to melt, and a methanol solution of potassium methoxide is added under a nitrogen atmosphere and stirred for 0.5-1 h.

[0010] Furthermore, the molar ratio of trimethylolpropane to glycidyl monomer is 1:1 to 1:21. By adjusting the above ratio, hyperbranched polyglycidyl ethers of different generations can be synthesized.

[0011] Furthermore, the concentration of potassium methoxide in the methanol solution of potassium methoxide is 0.31 mol / L.

[0012] Furthermore, the glycidyl monomer is added dropwise over 5 to 12 hours, and the reaction continues for another 5 to 12 hours after the addition is complete. After the reaction is complete, methanol is added, and the mixture is passed through a cation exchange resin, evaporated at 60 to 70°C, and then vacuum dried for 24 hours.

[0013] Furthermore, the saturated fatty acid includes one of caprylic acid and capric acid.

[0014] Furthermore, the molar mass of the saturated fatty acid is 14% to 17% of the molar mass of the hyperbranched polyglycerol ether end group, and the molar mass of the added CDI is 1.5 times the molar mass of the carboxyl group in the saturated fatty acid.

[0015] Furthermore, under ice bath conditions, CDI was added to the DMF solution of saturated fatty acids until it was completely dissolved. The mixture was stirred at room temperature for 1–2 hours until homogeneous. Then, it was added dropwise to the DMF solution of hyperbranched polyglycerol ether. Under a nitrogen atmosphere, the oil bath was heated to 45–55°C and the reaction was carried out for 5–12 hours.

[0016] Furthermore, the post-treatment of the reaction product includes: cooling to room temperature, diluting with anhydrous methanol, dialyzing with methanol through a cellulose dialysis membrane for 1-2 days, removing methanol by rotary evaporation, and vacuum drying for 24 hours.

[0017] In a second aspect, a rinsing agent prepared by the method described in the first aspect is provided.

[0018] Thirdly, an application of the leaching agent described in the second aspect is provided for the remediation of heavy metal contamination in sludge, the method comprising:

[0019] Remove impurities from the sludge, grind it, sieve it, air dry it naturally, add a leaching agent solution, mix it evenly, shake it, centrifuge it, and the supernatant obtained is the leaching waste liquid, and the lower solid is the leached sludge.

[0020] The leaching waste liquid was heated in a water bath until the leaching agent underwent a phase change. Then, it was centrifuged and filtered to obtain a precipitate of leaching agent-heavy metal complex.

[0021] The precipitate of the eluent-heavy metal complex was acid-washed to remove the heavy metals from the surface of the eluent, resulting in a recyclable eluent, and the heavy metals were collected.

[0022] Furthermore, the concentration of the rinsing agent solution is 5–20 mmol / L, and the liquid-to-solid ratio of the rinsing agent solution to the air-dried sludge is 10:1–20:1.

[0023] Furthermore, the temperature of the rinsing waste liquid heated in the water bath is 40-60°C, and the time is 5-10 minutes.

[0024] Furthermore, the acid used for acid washing of the leaching agent-heavy metal complex precipitate is hydrochloric acid or sulfuric acid.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention uses trimethylolpropane as the core and glycidyl ether as the monomer to synthesize hyperbranched polyglycerol ether, and then adds saturated fatty acids for end-group modification to prepare thermosensitive hyperbranched polyglycidyl ether. The hyperbranched polyglycerol ether has a three-dimensional spatial structure with numerous pores that can fully encapsulate heavy metal ions. Furthermore, the hyperbranched polymer contains abundant end-group groups, which can chelate and complex with different heavy metal ions, resulting in a high removal rate of heavy metals. In addition, the thermosensitive polymer has excellent applications in aqueous solution separation due to its temperature-sensitive properties. When used to wash sludge, the resulting leaching wastewater containing thermosensitive hyperbranched polymer and heavy metals can be precipitated from the aqueous solution by simply increasing the temperature, achieving solid-liquid separation. Therefore, the leaching agent prepared by this invention can significantly reduce the treatment cost of leaching wastewater while efficiently removing heavy metals. Detailed Implementation

[0027] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0028] Example 1

[0029] 0.238 g of trimethylolpropane was added to a three-necked flask and heated to 70 °C in an oil bath until it was completely melted. The mixture was repeatedly evacuated and purged with nitrogen. 2 ml of a 0.31 mol / L potassium methoxide methanol solution was added and stirred for 1 h. The methanol was then removed under vacuum. 2.769 g of glycidyl monomer was added dropwise over 10 h. After the addition was complete, the reaction continued for another 8 h. After the reaction was complete, anhydrous methanol was added to dissolve the crude product. After passing through a cation exchange resin, the product was evaporated at 60 °C and vacuum dried for 24 h to obtain third-generation hyperbranched glycidyl ether HPG-3.

[0030] Dissolve 0.26 g of HPG-3 in 3 ml of anhydrous DMF and set aside. Weigh 0.08 g of n-octanoic acid and dissolve it in 2 ml of anhydrous DMF. Slowly add 0.14 g of CDI under ice bath until completely dissolved. Continue stirring at room temperature for 1 h. Then add it dropwise to the HPG-3 DMF solution. Vacuum the flask and purge with nitrogen. Heat the oil bath to 55 °C and react for 8 h. After the solution cools to room temperature, dilute the reaction product with anhydrous methanol. Dialyze with methanol using a cellulose dialysis membrane with a molecular weight cutoff of 1000 for 1 day. Remove methanol by rotary evaporation and vacuum dry for 24 h to obtain the eluent HPG-33.

[0031] The dredged sludge was cleaned of debris such as gravel and large roots, ground, sieved through a 20-mesh sieve, and air-dried to obtain air-dried sludge. A 15 mmol / L solution of leaching agent HPG-33 was prepared by mixing HPG-33 with water. The air-dried sludge and HPG-33 solution were mixed at a solid-liquid ratio of 1:10 and shaken at room temperature for 6 hours. After shaking, the mixture was centrifuged at 9000 rpm for 15 minutes. The supernatant was the leaching waste liquid, and the lower solid layer was the leached sludge. The leaching waste liquid was heated to 55°C in a water bath and maintained for 10 minutes until a phase change occurred in the leaching agent. It was then rapidly centrifuged and filtered to obtain a leaching agent-heavy metal complex precipitate. The precipitate was then washed with hydrochloric acid to remove the heavy metals from the surface of the leaching agent, yielding recyclable HPG-33. The heavy metals were collected.

[0032] Example 2

[0033] 0.12 g of trimethylolpropane was added to a three-necked flask and heated to 70 °C in an oil bath until it was completely melted. The mixture was repeatedly evacuated and purged with nitrogen. 3 ml of a 0.31 mol / L potassium methoxide methanol solution was added and stirred for 1 h. The methanol was then removed by evacuation. 2.98 g of glycidyl monomer was added dropwise over 10 h. After the addition was complete, the reaction continued for another 10 h. After the reaction was complete, anhydrous methanol was added to dissolve the crude product. After passing through a cation exchange resin, the product was evaporated at 60 °C and vacuum dried for 24 h to obtain fourth-generation hyperbranched glycidyl ether HPG-4.

[0034] Dissolve 0.26 g of HPG-4 in 3 ml of anhydrous DMF and set aside. Weigh 0.07 g of n-octanoic acid and dissolve it in 2 ml of anhydrous DMF. Slowly add 0.13 g of CDI under ice bath until completely dissolved. Continue stirring at room temperature for 1 h. Then add it dropwise to the HPG-4 DMF solution. Vacuum the flask and purge with nitrogen. Heat the oil bath to 55 °C and react for 10 h. After the solution cools to room temperature, dilute the reaction product with anhydrous methanol. Dialyze the product with methanol using a cellulose dialysis membrane with a molecular weight cutoff of 1500 for 1 day. Remove methanol by rotary evaporation and vacuum dry for 24 h to obtain the eluent HPG-44.

[0035] The dredged sludge was cleaned of debris such as gravel and large roots, ground, sieved through a 20-mesh sieve, and air-dried to obtain air-dried sludge. A 12 mmol / L solution of HPG-44 leaching agent was prepared by mixing HPG-44 with water. The air-dried sludge and HPG-44 solution were mixed at a solid-liquid ratio of 1:10 and shaken at room temperature for 6 hours. The mixture was then centrifuged at 9000 rpm for 15 minutes to separate the solid and liquid phases. The supernatant was the leaching waste liquid, and the lower solid layer was the leached sludge. The leaching waste liquid was heated to 50°C in a water bath and maintained for 10 minutes until a phase change occurred. It was then rapidly centrifuged and filtered to obtain a precipitate of leaching agent-heavy metal complex. The precipitate was then washed with hydrochloric acid to remove the heavy metals from the surface of the leaching agent, yielding reusable HPG-44 leaching agent.

[0036] Example 3

[0037] 1.194 g of trimethylolpropane was added to a three-necked flask and heated to 75 °C in an oil bath until completely melted. The mixture was repeatedly evacuated and purged with nitrogen. 10 ml of a 0.31 mol / L potassium methoxide methanol solution was added and stirred for 0.5 h. The methanol was then removed under vacuum. 3.955 g of glycidyl monomer was added dropwise over 5 h. After the addition was complete, the reaction continued for 12 h. After the reaction was complete, anhydrous methanol was added to dissolve the crude product. After passing through a cation exchange resin, the product was evaporated at 70 °C and vacuum dried for 24 h to obtain second-generation hyperbranched glycidyl ether HPG-2.

[0038] Dissolve 0.33 g of HPG-2 in 3 ml of anhydrous DMF and set aside. Weigh 0.11 g of n-octanoic acid and dissolve it in 2 ml of anhydrous DMF. Slowly add 0.12 g of CDI under ice bath until completely dissolved. Continue stirring at room temperature for 2 h. Then add it dropwise to the HPG-2 DMF solution. Vacuum the flask and purge with nitrogen. Heat the oil bath to 45 °C and react for 12 h. After the solution cools to room temperature, dilute the reaction product with anhydrous methanol. Dialyze the product with methanol using a cellulose dialysis membrane with a molecular weight cutoff of 5000 for 1 day. Remove methanol by rotary evaporation and vacuum dry for 24 h to obtain the eluent HPG-22.

[0039] The dredged sludge was cleaned of debris such as gravel and large roots, ground, sieved through a 20-mesh sieve, and air-dried to obtain air-dried sludge. A 20 mmol / L solution of leaching agent HPG-22 was prepared by mixing HPG-22 with water. The air-dried sludge and HPG-22 solution were mixed at a solid-liquid ratio of 1:15 and shaken at room temperature for 6 hours. After shaking, the mixture was centrifuged at 9000 rpm for 15 minutes. The supernatant was the leaching waste liquid, and the lower solid layer was the leached sludge. The leaching waste liquid was heated to 60°C in a water bath and maintained for 5 minutes until a phase change occurred in the leaching agent. It was then rapidly centrifuged and filtered to obtain a leaching agent-heavy metal complex precipitate. The precipitate was then washed with hydrochloric acid to remove the heavy metals from the surface of the leaching agent, yielding recyclable leaching agent HPG-33. The heavy metals were collected.

[0040] Example 4

[0041] 0.238 g of trimethylolpropane was added to a three-necked flask and heated to 73 °C in an oil bath until completely melted. The mixture was repeatedly evacuated and purged with nitrogen. 2 ml of a 0.31 mol / L potassium methoxide methanol solution was added and stirred for 0.8 h. The methanol was then removed under vacuum. 6.329 g of glycidyl monomer was added dropwise over 12 h. After the addition was complete, the reaction continued for 5 h. After the reaction was complete, anhydrous methanol was added to dissolve the crude product. After passing through a cation exchange resin, the product was evaporated at 65 °C and vacuum dried for 24 h to obtain fifth-generation hyperbranched glycidyl ether HPG-5.

[0042] Dissolve 0.26 g of HPG-5 in 3 ml of anhydrous DMF and set aside. Weigh 0.47 g of n-octanoic acid and dissolve it in 2 ml of anhydrous DMF. Slowly add 0.51 g of CDI under ice bath until completely dissolved. Continue stirring at room temperature for 1.5 h. Then add it dropwise to the HPG-5 DMF solution. Vacuum the flask and purge with nitrogen. Heat the oil bath to 50 °C and react for 5 h. After the solution cools to room temperature, dilute the reaction product with anhydrous methanol. Dialyze the product with methanol using a cellulose dialysis membrane with a molecular weight cutoff of 2000 for 1 day. Remove the methanol by rotary evaporation and vacuum dry for 24 h to obtain the eluent HPG-55.

[0043] The dredged sludge was cleaned of debris such as gravel and large roots, ground, sieved through a 20-mesh sieve, and air-dried to obtain air-dried sludge. A 5 mmol / L solution of leaching agent HPG-55 was prepared by mixing HPG-55 with water. The air-dried sludge and HPG-55 solution were mixed at a solid-liquid ratio of 1:20 and shaken at room temperature for 6 hours. After shaking, the mixture was centrifuged at 9000 rpm for 15 minutes. The supernatant was the leaching waste liquid, and the lower solid layer was the leached sludge. The leaching waste liquid was heated to 40°C in a water bath and maintained for 8 minutes until a phase change occurred in the leaching agent. It was then rapidly centrifuged and filtered to obtain a precipitate of leaching agent-heavy metal complex. The precipitate was then washed with hydrochloric acid to remove the heavy metals from the surface of the leaching agent, yielding recyclable HPG-55 leaching agent. The heavy metals were collected.

[0044] The heavy metal content of the original dredged sludge and the sludge treated with the leaching agent in Examples 1 to 4 was detected, and the heavy metal removal rate was calculated. The results are shown in Table 1 below.

[0045] Table 1. Heavy metal removal rates of sludge in Examples 1-4

[0046] project Cd removal rate (%) Cu removal rate (%) Pb removal rate (%) Example 1 62.69 78.16 48.26 Example 2 66.38 83.96 50.63 Example 3 60.20 76.44 45.62 Example 4 70.75 88.26 53.96

[0047] As shown in Table 1, after treating heavy metal-contaminated sludge with the leaching agent prepared in this invention, the removal rates of Cd, Cu, and Pb in the sludge can reach 60%–70%, 75%–90%, and 45%–55%, respectively, demonstrating good heavy metal removal efficiency. Furthermore, the properties of the sludge remained unchanged after leaching, indicating that the leaching agent prepared in this invention did not damage the pores or agglomerate structure of the bottom sludge.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a rinsing agent, characterized in that, The leaching agent is used for the remediation of heavy metal pollution in sludge, and the method includes the following steps: A methanol solution of potassium methoxide was added to molten trimethylolpropane, stirred and then vacuumed. Glycidyl monomer was then added dropwise. After the reaction was complete, methanol was added and the mixture was dried to obtain hyperbranched polyglycerol ether. Under ice bath conditions, carbonyl imidazole was added to a saturated fatty acid N,N-dimethylformamide solution until it was completely dissolved. The mixture was stirred at room temperature for 1-2 hours until homogeneous. Then, it was added dropwise to a hyperbranched polyglycerol ether N,N-dimethylformamide solution. Under a nitrogen atmosphere, the oil bath was heated to 45-55°C and reacted for 5-12 hours. The product after reaction was post-treated to obtain a thermosensitive hyperbranched polyglycidyl ether eluent.

2. The method of claim 1, wherein the eluent is prepared by, The molar ratio of trimethylolpropane to glycidyl monomer is 1:1 to 1:

21.

3. The method of claim 1, wherein the eluent is prepared by, The glycidyl monomer was added dropwise over 5-12 hours. After the addition was complete, the reaction continued for another 5-12 hours. After the reaction was complete, methanol was added, and the mixture was passed through a cation exchange resin, evaporated at 60-70°C, and then vacuum dried for 24 hours.

4. The method of claim 1, wherein the eluent is prepared by, The saturated fatty acids include one of caprylic acid and capric acid.

5. The method of claim 1, wherein the eluent is prepared by, The molar mass of the saturated fatty acid is 14% to 17% of the molar mass of the end group of the hyperbranched polyglycerol ether, and the molar mass of the added carbonyl imidazole is 1.5 times the molar mass of the carboxyl group in the saturated fatty acid.

6. The method of claim 1, wherein the eluent is prepared by, The post-treatment of the reaction product includes: cooling to room temperature, diluting with anhydrous methanol, dialyzing with methanol through a cellulose dialysis membrane for 1-2 days, removing methanol by rotary evaporation, and vacuum drying for 24 hours.

7. A rinsing agent prepared by the method according to any one of claims 1 to 6.

8. Use of a rinse agent according to claim 7, characterized in that, Methods for remediating heavy metal contamination in sludge include: Remove impurities from the sludge, grind it, sieve it, air dry it naturally, add a leaching agent solution, mix it evenly, shake it, centrifuge it, and the supernatant obtained is the leaching waste liquid, and the lower solid is the leached sludge. The leaching waste liquid was heated in a water bath until the leaching agent underwent a phase change, and then centrifuged and filtered to obtain a precipitate of leaching agent-heavy metal complex. The water bath heating temperature of the leaching waste liquid was 40~60℃ and the time was 5~10 min. The precipitate of the eluent-heavy metal complex was acid-washed to remove the heavy metals from the surface of the eluent, resulting in a recyclable eluent, and the heavy metals were collected.

9. Use of a rinse agent according to claim 8, characterized in that The concentration of the rinsing agent solution is 5~20 mmol / L, and the liquid-solid ratio of the rinsing agent solution to the air-dried sludge is 10:1~20:1.