Industrial wastewater heavy metal and hardness treatment agent, and preparation method and application thereof

Abstract

This invention relates to the field of wastewater treatment technology and discloses an industrial wastewater heavy metal and hardness treatment agent, its preparation method, and its application. The invention involves polymerizing an ethylenediaminetetramethacrylate (EDTA) monomer containing hydroxyl and carboxyl groups with an EDTA crosslinking agent containing multiple hydroxyl groups. Then, some of the hydroxyl groups undergo a condensation reaction with phosphoric acid under the catalysis of urea to generate phosphate ester groups. The resulting industrial wastewater heavy metal and hardness treatment agent contains carboxyl, hydroxyl, and phosphate groups and has strong adsorption performance for heavy metal ions such as copper, lead, and cadmium. It also exhibits good adsorption effects on calcium and magnesium. It has good practical applications in treating industrial wastewater containing heavy metals and adjusting the hardness of hard water.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to heavy metal and hardness treatment agents for industrial wastewater, their preparation methods, and applications. Background Technology

[0002] While my country's industry has developed rapidly, it has also generated a large amount of pollutants such as solid waste and wastewater. Industrial wastewater contains a large amount of metal ions such as copper, lead, calcium, and magnesium. If discharged into natural water bodies without effective treatment, it will pollute the aquatic environment, increase water hardness, and cause serious pollution and damage to the ecological environment and agricultural irrigation. Currently, adsorption and sedimentation methods are the main methods used to treat industrial wastewater.

[0003] Polyacrylic acid adsorption resins contain a large number of carboxyl groups, which form coordination bonds and ionic bonds with metal ions, achieving effective adsorption of metals. They have wide applications in wastewater treatment and water hardness adjustment. To improve the adsorption performance of the resin, functional groups such as hydroxyl, amino, and phosphate groups can be introduced. Patent application CN120025490A discloses a hydrogel with calcium ion adsorption function and its preparation and application. Sodium acrylate, sodium vinyl phosphate, a crosslinking agent, an initiator, and styrene are reacted to obtain a hydrogel with good calcium ion adsorption performance. However, this hydrogel does not contain active groups such as hydroxyl groups and does not exhibit adsorption performance for heavy metals such as lead and copper. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an industrial wastewater heavy metal and hardness treatment agent, its preparation method, and its application, solving the problem of poor adsorption performance of traditional polyacrylic acid resins for metals such as lead, copper, calcium, and magnesium.

[0005] The technical solution of this invention is: a method for preparing heavy metals and hardness treatment agents from industrial wastewater. (1) Add water, serine, sodium carbonate, and acetonitrile to a flask. Add allyl chloroformate dropwise in an ice bath and stir to carry out the reaction. Remove acetonitrile by vacuum distillation. Add hydrochloric acid dropwise and extract with ethyl acetate. Add anhydrous magnesium sulfate to the organic layer and dry. Filter and distill the filtrate under vacuum to obtain N-allyloxycarbonylserine. The preparation reaction formula is: .

[0006] (2) Add deionized water, N-allyloxycarbonylserine and glycidyl ethylenediaminetetramethacrylate to the flask, stir and then pass nitrogen gas through, add an aqueous solution of initiator dropwise, stir to react, filter and wash the product with an aqueous ethanol solution, then add it to deionized water to soak and wash, dry, and obtain the treatment agent precursor.

[0007] (3) Add deionized water, treatment agent precursor, phosphoric acid and urea to a flask containing reflux condenser, stir to react, filter and wash with ethanol aqueous solution, add the product to deionized water to soak and wash, dry to obtain industrial wastewater heavy metal and hardness treatment agent.

[0008] Furthermore, in (1), the molar ratio of serine, sodium carbonate, and allyl chloroformate is 1:(1-1.5):(1-1.1).

[0009] Furthermore, the reaction in (1) is stirred at 20-25°C for 12-18 hours.

[0010] Furthermore, in (1), hydrochloric acid is added dropwise to adjust the pH to 2-3.

[0011] Furthermore, in (2), the molar ratio of N-allyloxycarbonylserine, ethylenediaminetetramethacrylate glycidyl ester, and initiator is 100:(1-3):(0.25-0.35).

[0012] Furthermore, in (2), the initiator is ammonium persulfate or potassium persulfate.

[0013] Furthermore, in (2), the reaction temperature is 50-65℃ and the reaction time is 8-12h.

[0014] Furthermore, in (3), the mass ratio of the treatment agent precursor, phosphoric acid, and urea is 100:(160-220)g:(6-9).

[0015] Furthermore, in (3), the reaction is first stirred at 50-60℃ for 6-9h, and then stirred at 90-95℃ for 8-12h.

[0016] Furthermore, heavy metal and hardness treatment agents for industrial wastewater are applied to the treatment of heavy metals in industrial wastewater and the reduction of water hardness.

[0017] (III) Beneficial Technical Effects: This invention uses ethylenediaminetetramethacrylate (EDTA) monomers containing hydroxyl and carboxyl groups to polymerize with EDTA crosslinking agents containing multiple hydroxyl groups. Then, some hydroxyl groups (-OH) react with phosphoric acid ( ) under the catalysis of urea. A condensation reaction occurs, producing phosphate ester groups ( The resulting industrial wastewater heavy metal and hardness treatment agent contains carboxyl, hydroxyl, and phosphate groups, exhibiting strong adsorption performance for heavy metal ions such as copper, lead, and cadmium, while also showing good adsorption effects for calcium and magnesium. It has excellent practical applications in treating industrial wastewater containing heavy metals and adjusting the hardness of hard water. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments.

[0019] Glycidyl ethylenediaminetetramethacrylate was prepared according to the method described in the journal article "UV-curable waterborne inks and abrasion resistance of ink films" in *Applied Chemistry*. The structural formula is: .

[0020] Example 1 (1) Add 80 mL of water, 80 mmol of serine, 84 mmol of sodium carbonate and 40 mL of acetonitrile to a flask, add 88 mmol of allyl chloroformate dropwise in an ice bath, stir and react at 20 °C for 12 h, remove acetonitrile by vacuum distillation, adjust pH to 2 by adding hydrochloric acid, extract and separate with ethyl acetate, add anhydrous magnesium sulfate to the organic layer and dry, filter and distill the filtrate under vacuum to obtain N-allyloxycarbonyl serine.

[0021] (2) Add 100 mL of deionized water, 60 mmol of N-allyloxycarbonylserine, and 0.6 mmol of ethylenediaminetetramethacrylate to the flask. After stirring, purge with nitrogen gas and add 0.15 mmol of potassium persulfate aqueous solution. Heat to 60 °C and stir for 8 h. After filtration, wash the product with 30% ethanol aqueous solution. Then soak and wash in deionized water and dry to obtain the treatment agent precursor.

[0022] (3) Add 2L of deionized water, 10g of treatment agent precursor, 16g of phosphoric acid and 0.6g of urea to a flask containing reflux condenser. First, stir the reaction at 50℃ for 8h, then stir the reaction at 95℃ for 8h. After filtration, wash with 80% ethanol aqueous solution. Add the product to deionized water for soaking and washing, and dry to obtain industrial wastewater heavy metal and hardness treatment agent.

[0023] Example 2 (1) Add 80 mL of water, 80 mmol of serine, 84 mmol of sodium carbonate and 40 mL of acetonitrile to a flask, add 84 mmol of allyl chloroformate dropwise in an ice bath, stir and react at 25 °C for 12 h, remove acetonitrile by vacuum distillation, adjust the pH to 3 by adding hydrochloric acid, extract and separate with ethyl acetate, add anhydrous magnesium sulfate to the organic layer and dry, filter and distill the filtrate under vacuum to obtain N-allyloxycarbonyl serine.

[0024] (2) Add 150 mL of deionized water, 60 mmol of N-allyloxycarbonylserine, and 1.2 mmol of ethylenediaminetetramethacrylate to a flask, stir, purge with nitrogen, add 0.17 mmol of potassium persulfate aqueous solution, heat to 50 °C, stir and react for 12 h, filter, wash the product with 30% ethanol aqueous solution, then soak and wash in deionized water, dry, and obtain the treatment agent precursor.

[0025] (3) Add 2.5L of deionized water, 10g of treatment agent precursor, 20g of phosphoric acid and 0.74g of urea to a flask containing reflux condenser. First, stir the reaction at 50℃ for 9h, then stir the reaction at 95℃ for 10h. After filtration, wash with 80% ethanol aqueous solution. Add the product to deionized water for soaking and washing, and dry to obtain industrial wastewater heavy metal and hardness treatment agent.

[0026] Example 3 (1) Add 80 mL of water, 80 mmol of serine, 88 mmol of sodium carbonate and 40 mL of acetonitrile to a flask, add 88 mmol of allyl chloroformate dropwise in an ice bath, stir and react at 20 °C for 18 h, remove acetonitrile by vacuum distillation, adjust pH to 2 by adding hydrochloric acid, extract and separate with ethyl acetate, add anhydrous magnesium sulfate to the organic layer and dry, filter and distill the filtrate under vacuum to obtain N-allyloxycarbonyl serine.

[0027] (2) Add 180 mL of deionized water, 60 mmol of N-allyloxycarbonylserine, and 1.8 mmol of ethylenediaminetetramethacrylate to the flask, stir, and then purge with nitrogen gas. Add 0.21 mmol of ammonium persulfate aqueous solution dropwise, heat to 65 °C, stir and react for 8 h, filter, wash the product with 30% ethanol aqueous solution, then soak and wash in deionized water, dry, and obtain the treatment agent precursor.

[0028] (3) Add 3L of deionized water, 10g of treatment agent precursor, 22g of phosphoric acid and 0.9g of urea to a flask containing reflux condenser. First, stir the reaction at 60℃ for 6h, then stir the reaction at 90℃ for 12h. After filtration, wash with 80% ethanol aqueous solution. Add the product to deionized water for soaking and washing, and dry to obtain industrial wastewater heavy metal and hardness treatment agent.

[0029] Comparative Example 1 uses the treatment agent precursor prepared in Example 1 as the treatment agent.

[0030] Comparative Example 2 (1) 100 mL of deionized water, 60 mmol of acrylic acid, and 0.6 mmol of glycidyl ethylenediaminetetramethacrylate were added to a flask. After stirring, nitrogen gas was introduced, and 0.15 mmol of potassium persulfate aqueous solution was added dropwise. The mixture was heated to 60 °C and stirred for 8 h. After filtration, the product was washed with 30% ethanol aqueous solution. Then, it was soaked and washed in deionized water and dried to obtain the treatment agent precursor.

[0031] (2) Add 2L of deionized water, 10g of treatment agent precursor, 16g of phosphoric acid and 0.6g of urea to a flask equipped with reflux condenser. Stir at 50℃ for 8h, then stir at 95℃ for 8h. After filtration, wash with 80% ethanol aqueous solution. Soak and wash the product in deionized water, and dry to obtain the treatment agent.

[0032] Comparative Example 3 (1) 100 mL of deionized water, 60 mmol of N-allyloxycarbonylserine, and 0.6 mmol of pentaerythritol tetraacrylate were added to a flask. After stirring, nitrogen gas was introduced, and 0.15 mmol of potassium persulfate aqueous solution was added dropwise. The mixture was heated to 60 °C and stirred for 8 h. After filtration, the product was washed with 30% ethanol aqueous solution. Then, it was soaked and washed in deionized water and dried to obtain the treatment agent precursor.

[0033] (2) Add 2L of deionized water, 10g of treatment agent precursor, 16g of phosphoric acid and 0.6g of urea to a flask containing reflux condenser. First, stir the reaction at 50℃ for 8h, then stir the reaction at 95℃ for 8h. After filtration, wash with 80% ethanol aqueous solution. Add the product to deionized water for soaking and washing, and dry to obtain the treatment agent.

[0034] Comparative Example 4 (1) 100 mL of deionized water, 30 mmol of acrylic acid, 30 mmol of hydroxyethyl acrylate, and 0.6 mmol of glycidyl ethylenediaminetetramethacrylate were added to a flask. After stirring, nitrogen gas was introduced, and 0.15 mmol of potassium persulfate aqueous solution was added dropwise. The mixture was heated to 60 °C and stirred for 8 h. After filtration, the product was washed with 30% ethanol aqueous solution. Then, it was soaked and washed in deionized water and dried to obtain the treatment agent precursor.

[0035] (2) Add 2L of deionized water, 10g of treatment agent precursor, 16g of phosphoric acid and 0.6g of urea to a flask containing reflux condenser. First, stir the reaction at 50℃ for 8h, then stir the reaction at 95℃ for 8h. After filtration, wash with 80% ethanol aqueous solution. Add the product to deionized water for soaking and washing, and dry to obtain the treatment agent.

[0036] 1L Cu configuration 2+A standard solution with a concentration of 200 mg / L (CO) was mixed with 1.5 g of chelating agent, and the mixture was stirred and adsorbed at 25 °C for 2 h. The supernatant was then collected, and the Cu content of the solution after adsorption was measured by atomic absorption spectrometry. 2+ The concentration (C) is used to calculate the removal rate Q, Q = (C0 - C) / C × 100%.

[0037] 1L Pb configuration 2+ A standard solution with a concentration of 200 mg / L (CO) was mixed with 2 g of chelating agent and stirred at 25 °C for 2 h for adsorption. The supernatant was then collected, and the Pb content of the adsorbed solution was determined by atomic absorption spectrometry. 2+ The concentration (C) is used to calculate the removal rate Q, Q = (C0 - C) / C × 100%.

[0038] 1L Cd configuration 2+ A standard solution with a concentration of 200 mg / L (CO) was mixed with 2 g of chelating agent and stirred at 25 °C for 3 h for adsorption. The supernatant was then collected, and the Cd content of the solution after adsorption was determined by atomic absorption spectrometry. 2+ The concentration (C) is used to calculate the removal rate Q, Q = (C0 - C) / C × 100%.

[0039] Configuration 1L Ca 2+ A standard solution with a concentration of 200 mg / L (CO) was mixed with 1.5 g of chelating agent, and the mixture was stirred and adsorbed at 25 °C for 2 h. The supernatant was then collected, and the CaO content of the solution after adsorption was measured by atomic absorption spectrometry. 2+ The concentration (C) is used to calculate the removal rate Q, Q = (C0 - C) / C × 100%.

[0040] Configure 1L Mg 2+ A standard solution with a concentration of 200 mg / L (CO) was mixed with 2 g of chelating agent, and the mixture was stirred and adsorbed at 25 °C for 2 h. The supernatant was then collected, and the Mg content of the solution after adsorption was measured by atomic absorption spectrometry. 2+ The concentration (C) is used to calculate the removal rate Q, Q = (C0 - C) / C × 100%.

[0041] Table 1 Removal Rate Test

[0042] The industrial wastewater heavy metal and hardness treatment agents in each embodiment contain active groups such as carboxyl, hydroxyl, and phosphoric acid, which have stronger adsorption performance and high removal rate for metal ions such as copper, lead, cadmium, calcium, and magnesium.

[0043] The precursor of the treatment agent in Comparative Example 1 does not contain phosphate groups, and its adsorption performance for metal ions is lower than that in Example 1, resulting in a lower removal rate.

[0044] In Comparative Example 2, acrylic acid was used instead of N-allyloxycarbonylserine. The hydroxyl content of the resulting treatment agent precursor was significantly lower than that in Example 1. After reacting with phosphoric acid, the prepared treatment agent had lower phosphate groups and hydroxyl content. The adsorbent's adsorption performance for metal ions was lower than that in Example 1, resulting in a lower removal rate.

[0045] Comparative Example 3 used pentaerythritol tetraacrylate, which does not contain hydroxyl groups, as a crosslinking agent. The precursor of the treatment agent prepared had fewer hydroxyl groups than in Example 1, resulting in fewer phosphate groups in the treatment agent than in Example 1. The removal rate of metal ions by the adsorbent was slightly lower than that in Example 1.

[0046] In Comparative Example 4, acrylic acid and hydroxyethyl acrylate (total 60 mmol) were used instead of N-allyloxycarbonylserine (60 mmol). The carboxyl and hydroxyl content of the prepared treatment agent precursor was only half that of the treatment agent precursor in Example 1. After the hydroxyl group reacted with phosphoric acid, the phosphoric acid content of the prepared treatment agent was also less than that in Example 1, and the removal rate of metal ions was significantly lower than that in Example 1.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing heavy metal and hardness treatment agents for industrial wastewater, characterized in that, The preparation method is as follows: (1) Add deionized water, N-allyloxycarbonylserine and glycidyl ethylenediaminetetramethacrylate to a flask, stir and then pass nitrogen gas through, add an aqueous solution of initiator dropwise, stir the reaction, filter and wash the product, soak and wash, dry, and obtain the treatment agent precursor. (2) Add deionized water, treatment agent precursor, phosphoric acid and urea to a flask containing reflux condenser, stir to react, filter and wash the product, soak and wash, dry to obtain industrial wastewater heavy metal and hardness treatment agent.

2. The preparation method of the heavy metal and hardness treatment agent for industrial wastewater according to claim 1, characterized in that, The molar ratio of N-allyloxycarbonylserine, ethylenediaminetetramethacrylate glycidyl ester, and initiator in (1) is 100:(1-3):(0.25-0.35).

3. The preparation method of the heavy metal and hardness treatment agent for industrial wastewater according to claim 2, characterized in that, The initiator is ammonium persulfate or potassium persulfate.

4. The preparation method of the heavy metal and hardness treatment agent for industrial wastewater according to claim 1, characterized in that, The reaction temperature in (1) is 50-65℃ and the reaction time is 8-12h.

5. The method for preparing the heavy metal and hardness treatment agent for industrial wastewater according to claim 1, characterized in that, The mass ratio of the treatment agent precursor, phosphoric acid and urea in (2) is 100:(160-220)g:(6-9).

6. The method for preparing heavy metal and hardness treatment agents for industrial wastewater according to claim 1, characterized in that, The reaction in (2) is first stirred at 50-60℃ for 6-9h, and then stirred at 90-95℃ for 8-12h.

7. The method for preparing the heavy metal and hardness treatment agent for industrial wastewater according to claim 3, characterized in that, The preparation method of N-allyloxycarbonylserine is as follows: water, serine, sodium carbonate, and acetonitrile are added to a flask, allyl chloroformate is added dropwise in an ice bath, and the mixture is stirred and reacted at 20-25℃ for 12-18h. Acetonitrile is removed by vacuum distillation, and hydrochloric acid is added dropwise to adjust the pH to 2-3. The mixture is then extracted and separated to obtain N-allyloxycarbonylserine.

8. The method for preparing the heavy metal and hardness treatment agent for industrial wastewater according to claim 6, characterized in that, The molar ratio of serine, sodium carbonate, and allyl chloroformate is 1:(1-1.5):(1-1.1).

9. An industrial wastewater heavy metal and hardness treatment agent obtained by the preparation method according to any one of claims 1-8.

10. An industrial wastewater heavy metal and hardness treatment agent as described in claim 9, applied to the treatment of heavy metals in industrial wastewater and the reduction of water hardness.

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