Adsorbing material for mercury-containing wastewater and preparation method thereof

Abstract

The invention belongs to the field of material preparation, and particularly relates to a mercury-containing wastewater adsorbing material and a preparation method thereof.The preparation method comprises the following steps that corn straw is treated with a sodium hydroxide solution and dispersed in a mixed system of acetone and deionized water; heating to 50-60 DEG C, introducing nitrogen to remove oxygen, adding an initiator diisopropyl peroxydicarbonate and a monomer glyceryl methacrylate, continuously introducing nitrogen, and reacting for 2-3 hours; cooling the system to room temperature under the protection of nitrogen, and performing suction filtration to obtain a crude product; and dissolving the branched polyethyleneimine in N, N-dimethylformamide, adding the obtained crude product, reacting for 10-12 hours under the protection of nitrogen and under the condition that the water bath temperature is 60-80 DEG C, washing the crude product with water and ethanol, and drying to constant weight to obtain the mercury-containing wastewater adsorbing material. The method has the technical advantages of high mercury removal rate, stable process conditions and no secondary pollution to the environment.

Description

Technical Field

[0001] The invention belongs to the field of materials, and in particular relates to an adsorption material for mercury-containing wastewater and a preparation method thereof. Background Art

[0002] With the development of the metallurgical and chemical industries, mining, electroplating, and manufacturing have generated significant amounts of heavy metal pollutants, causing serious environmental problems and posing a significant threat to human health. Mercury (Hg) is a highly toxic heavy metal. Even trace amounts of mercury can cause irreversible damage to organs such as the liver and kidneys. Therefore, the treatment of mercury-containing wastewater has become a major issue that requires urgent resolution.

[0003] Traditional methods for treating mercury-containing wastewater primarily utilize sulfide precipitation, adsorption, ion exchange, metal reduction, microbial concentration, and solvent extraction. Treatment effectiveness and cost depend on the mercury's form, initial concentration, coexisting ions in the wastewater, and effluent quality requirements. In practice, sulfide precipitation is simple to operate and suitable for mercury-containing wastewater with high initial concentrations. Adsorption, which uses activated carbon, fly ash, wool, or adsorption resins as adsorption materials, is more expensive but can treat mercury-containing wastewaters of varying concentrations. Ion exchange is suitable for treating low-concentration wastewater with high discharge volumes, with effluent mercury concentrations below 5 μg / L, but expired resins cannot be regenerated.

[0004] Chinese patent 202110227850.5 discloses a high-performance demercuration oleophobic filter fiber membrane based on agricultural straw fiber and its preparation method, which uses cheap and easily available natural plant fiber (straw) as raw material, and through simple hydrothermal pretreatment, enhanced mercury ion targeted adsorption, organic-inorganic composite fiber reinforcement and oleophobic modification series methods, the prepared bio-based fiber membrane is suitable for the adsorption of mercury ions contained in oil and gas field wastewater and the filtration and removal of mercury suspension (including elemental mercury), and has good separation performance for oil and organic polymers and water. The preparation process of this method is complicated and the production cost is high, which is not conducive to technology promotion. In view of this, the present invention provides an adsorbent material for mercury-containing wastewater with low cost and high removal efficiency and its preparation method. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides an adsorption material for mercury-containing wastewater and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the present application provides an adsorption material for mercury-containing wastewater and a preparation method thereof, which adopts the following technical scheme: A mercury-containing wastewater adsorption material, with corn straw as the skeleton, diisopropyl peroxydicarbonate as the initiator, monomer methacrylate glycerol ester, and branched polyethyleneimine as modified functional reagents.

[0007] By volume, the ratio of corn straw to glyceryl methacrylate is 1:1, diisopropyl peroxydicarbonate is 5%-8% of the monomer glyceryl methacrylate, and branched polyethyleneimine is 20%-70% of the monomer glyceryl methacrylate.

[0008] By volume, the diisopropyl peroxydicarbonate accounts for 6%-7% of the monomer glycerol methacrylate, and the branched polyethyleneimine accounts for 30%-60% of the monomer glycerol methacrylate.

[0009] The branched polyethyleneimine is 40% to 50% by volume of the monomer glycerol methacrylate.

[0010] A method for preparing a mercury-containing wastewater adsorption material comprises the following steps: (1) Treat 100-200 mesh corn stalks with 10%-20% sodium hydroxide solution for 10-30 minutes, drain, and disperse in a mixture of acetone and deionized water; (2) The mixed system in step (1) is heated to 50-60°C, and nitrogen is introduced to deoxygenate for 10-15 minutes, and then the initiator diisopropyl peroxydicarbonate and the monomer glycerol methacrylate are added, and nitrogen is continuously introduced at 50-60°C to react for 1-4 hours; (3) Cooling the mixed system of step (2) to room temperature under nitrogen protection, obtaining a crude product by suction filtration, and washing it with deionized water and acetone to remove unreacted monomers and initiator; (4) The branched polyethyleneimine is dissolved in N,N-dimethylformamide, and the crude product obtained in step (3) is added. The reaction is carried out under nitrogen protection at a water bath temperature of 60-80°C for 8-14 hours. The obtained product is washed with water and ethanol to remove the unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to a constant weight to obtain a mercury-containing wastewater adsorbent material.

[0011] Further, the following steps are included: (1) Treat 120-180 mesh corn stalks with 12%-18% sodium hydroxide solution for 15-25 minutes, drain, and disperse in a mixture of acetone and deionized water; (2) The mixed system in step (1) is heated to 52-58°C, and nitrogen is introduced to deoxygenate for 10-15 minutes. Then, the initiator diisopropyl peroxydicarbonate and the monomer glycerol methacrylate are added, and nitrogen is continuously introduced at 52-58°C to react for 2-3 hours; (3) Cooling the mixed system of step (2) to room temperature under nitrogen protection, obtaining a crude product by suction filtration, and washing it with deionized water and acetone to remove unreacted monomers and initiator; (4) The branched polyethyleneimine is dissolved in N,N-dimethylformamide, and the crude product obtained in step (3) is added. The reaction is carried out under nitrogen protection at a water bath temperature of 65-75°C for 10-12 hours. The obtained product is washed with water and ethanol to remove the unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to a constant weight to obtain a mercury-containing wastewater adsorbent material.

[0012] The method for preparing a mercury-containing wastewater adsorbent material according to claim 5, wherein the concentration of the branched polyethyleneimine in N,N-dimethylformamide is 0.03 mol / L-0.05 mol / L. (1) The cellulose in corn stalks has good chemical stability and mechanical strength as a polymer skeleton. The molecules are arranged tightly and orderly, and the cellulose crystal regions formed by strong hydrogen bonds give the cellulose polymer skeleton a certain strength, anti-swelling property and specific surface area, which can adsorb Hg. 2+ .

[0013] (2) Branched polyethyleneimine contains nitrogen atoms, whose free electron pairs can react with Hg 2+ Form a stable complex.

[0014] (3) The proportion of nitrogen-containing polar groups in branched polyethyleneimine is extremely high, and the ratio of amine, secondary amine and tertiary amine is 1:2:1, which is very effective for Hg 2+ It has strong chelating and adsorption effects.

[0015] (4) Glyceryl methacrylate is a functional monomer. The hydroxyl groups and double bonds can form a polymer skeleton through polymerization reactions (such as free radical polymerization), while retaining the modifiable hydroxyl groups, which is convenient for the modification of branched polyethyleneimine.

[0016] (5) The hydroxyl groups in glyceryl acrylate give the material good hydrophilicity, and copolymerize with cellulose and branched polyethyleneimine to form a three-dimensional network structure, which enhances the stability and adsorption capacity of the material and is suitable for adsorbing Hg in wastewater solutions. 2+ . DETAILED DESCRIPTION

[0017] The present application will be described in detail below with reference to the embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations can be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as part of one embodiment can be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention should fall within the scope of protection of the embodiments of the present invention. Example

[0018] An adsorbent material for mercury-containing wastewater and a preparation method thereof, comprising the steps of drying corn stalks and then crushing them to 150 mesh using a jet mill, treating 100 mL of the 150-mesh corn stalks with a 15% sodium hydroxide solution, draining the mixture after 25 minutes, and dispersing the mixture in a mixture of 100 mL of acetone and deionized water, heating the mixture to 50°C, introducing nitrogen for deoxygenation for 10 minutes, adding 6 mL of diisopropyl peroxydicarbonate as an initiator, and 100 mL of glycerol methacrylate as a monomer, reacting the mixture by continuously introducing nitrogen at 55°C for 3 hours, cooling the mixture to room temperature under nitrogen protection, and obtaining a crude product by suction filtration. The crude product was washed with water and acetone to remove unreacted monomers and initiators, and 120 mL of a 0.03 mol / L branched polyethyleneimine in N,N-dimethylformamide solution was added. The mixture was reacted for 12 hours in a water bath at 70°C under nitrogen protection. The crude product was washed with water and ethanol to remove unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to constant weight to obtain a mercury-containing wastewater adsorbent. The adsorbent was placed in 1 L of mercury-containing wastewater with a mercury content of 0.12 mg / L. After adsorption for 12 hours, the mercury content was 0.002 mg / L, and the mercury removal rate was 98.3%. Example

[0019] A mercury-containing wastewater adsorption material and a preparation method thereof include treating 100 mL of 100-mesh corn stalks with a 10% sodium hydroxide solution for 25 minutes, draining the mixture, and dispersing the mixture in a mixture of acetone and deionized water. The mixture is heated to 60°C, and nitrogen is introduced for deoxygenation for 15 minutes. Then, 5 mL of diisopropyl peroxydicarbonate (initiator) and 100 mL of glycerol methacrylate (monomer) are added. Nitrogen is continuously introduced at 50°C for reaction for 2 hours. After cooling to room temperature under nitrogen protection, a crude product is obtained by suction filtration, and the crude product is washed with deionized water and acetone to remove mercury. Unreacted monomers and initiators were added to 100 mL of a 0.04 mol / L branched polyethyleneimine N,N-dimethylformamide solution, and reacted for 10 hours in a water bath at 60°C under nitrogen protection. The crude product was washed with water and ethanol to remove unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to constant weight to obtain a mercury-containing wastewater adsorption material. The adsorption material was placed in 1 L of mercury-containing wastewater with a mercury content of 0.15 mg / L and adsorbed for 12 hours. The mercury content was 0.0017 mg / L, and the mercury removal rate was 98.87%. Example

[0020] A mercury-containing wastewater adsorption material and a preparation method thereof include treating 100 mL of 200-mesh corn stalks with a 20% sodium hydroxide solution for 30 minutes, draining the mixture, and dispersing the mixture in a mixture of acetone and deionized water. The mixture is heated to 55°C, and nitrogen is introduced for deoxygenation for 13 minutes. Then, 8 mL of diisopropyl peroxydicarbonate (initiator) and 100 mL of glycerol methacrylate (monomer) are added. Nitrogen is continuously introduced at 50°C for reaction for 3 hours. After cooling to room temperature under nitrogen protection, a crude product is obtained by suction filtration and washed with deionized water and acetone to remove mercury. Unreacted monomers and initiators were added to 100 mL of a 0.05 mol / L branched polyethyleneimine N,N-dimethylformamide solution, and reacted for 10 hours in a water bath at 80°C under nitrogen protection. The crude product was washed with water and ethanol to remove unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to constant weight to obtain a mercury-containing wastewater adsorbent. The adsorbent material was placed in 1 L of mercury-containing wastewater with a mercury content of 0.18 mg / L and adsorbed for 12 hours. The mercury content was 0.0015 mg / L, and the mercury removal rate was 99.2%.

Claims

1. A mercury-containing wastewater adsorption material, characterized in that: Corn straw is used as the skeleton, diisopropyl peroxydicarbonate is used as the initiator, monomer glycerol methacrylate and branched polyethyleneimine are used as the modification functional reagents.

2. The mercury-containing wastewater adsorption material according to claim 1, characterized in that: By volume, the ratio of corn straw to glyceryl methacrylate is 1:1, diisopropyl peroxydicarbonate is 5%-8% of the monomer glyceryl methacrylate, and branched polyethyleneimine is 20%-70% of the monomer glyceryl methacrylate.

3. The mercury-containing wastewater adsorption material according to claim 2, characterized in that: By volume, the diisopropyl peroxydicarbonate accounts for 6%-7% of the monomer glycerol methacrylate, and the branched polyethyleneimine accounts for 30%-60% of the monomer glycerol methacrylate.

4. The mercury-containing wastewater adsorption material according to claim 3, characterized in that: The branched polyethyleneimine is 40% to 50% by volume of the monomer glycerol methacrylate.

5. The method for preparing a mercury-containing wastewater adsorption material according to any one of claims 1 to 4, characterized in that: The steps include: (1) Treat 100-200 mesh corn stalks with 10%-20% sodium hydroxide solution for 10-30 minutes, drain, and disperse in a mixture of acetone and deionized water; (2) The mixed system in step (1) is heated to 50-60°C, and nitrogen is introduced to deoxygenate for 10-15 minutes, and then the initiator diisopropyl peroxydicarbonate and the monomer glycerol methacrylate are added, and nitrogen is continuously introduced at 50-60°C to react for 1-4 hours; (3) Cooling the mixed system of step (2) to room temperature under nitrogen protection, obtaining a crude product by suction filtration, and washing it with deionized water and acetone to remove unreacted monomers and initiator; (4) The branched polyethyleneimine is dissolved in N,N-dimethylformamide, and the crude product obtained in step (3) is added. The reaction is carried out under nitrogen protection at a water bath temperature of 60-80°C for 8-14 hours. The obtained product is washed with water and ethanol to remove the unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to a constant weight to obtain a mercury-containing wastewater adsorbent material.

6. The method for preparing a mercury-containing wastewater adsorption material according to claim 5, characterized in that: The steps include: (1) Treat 120-180 mesh corn stalks with 12%-18% sodium hydroxide solution for 15-25 minutes, drain, and disperse in a mixture of acetone and deionized water; (2) The mixed system in step (1) is heated to 52-58°C, and nitrogen is introduced to deoxygenate for 10-15 minutes. Then, the initiator diisopropyl peroxydicarbonate and the monomer glycerol methacrylate are added, and nitrogen is continuously introduced at 52-58°C to react for 2-3 hours; (3) Cooling the mixed system of step (2) to room temperature under nitrogen protection, obtaining a crude product by suction filtration, and washing it with deionized water and acetone to remove unreacted monomers and initiator; (4) The branched polyethyleneimine is dissolved in N,N-dimethylformamide, and the crude product obtained in step (3) is added. The reaction is carried out under nitrogen protection at a water bath temperature of 65-75°C for 10-12 hours. The obtained product is washed with water and ethanol to remove the unreacted branched polyethyleneimine and N,N-dimethylformamide, and then dried to a constant weight to obtain a mercury-containing wastewater adsorbent material.

7. The method for preparing a mercury-containing wastewater adsorption material according to claim 5, characterized in that: The concentration of branched polyethyleneimine in N,N-dimethylformamide is 0.03 mol / L-0.05 mol / L.