Resin and electrooxidation combined treatment method for dimethylacetamide wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a resin and electrooxidation combined treatment method for dimethylacetamide wastewater. The preparation process comprises the following steps: crosslinking lignocellulose and styrene particles; preparing lignocellulose / vinylpyridine modified resin; preparing acetamide adsorption resin; the invention relates to resin and electrooxidation combined treatment of dimethylacetamide wastewater. According to the present invention, after the lignocellulose and the styrene are subjected to cross-linking, the lignocellulose and the vinyl pyridine monomer are further subjected to cross-linking so as to form the multi-dimensional cross-linked network resin with the vinyl pyridine as the substrate, and the lignocellulose and the styrene are co-grafted, such that the adsorption efficiency on the dimethylacetamide is significantly improved; groups in vinylpyridine can serve as functional groups to be introduced into resin, lignocellulose contains active groups, the groups can have a synergistic effect with pyridine rings after crosslinking, and the adsorption capacity on dimethylacetamide is further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a resin and electro-oxidation combined treatment method for dimethylacetamide wastewater. Background Art

[0002] Dimethylacetamide (DMAC) is an important organic solvent, widely used in chemical, pharmaceutical, fiber and other industries. DMAC is very harmful to aquatic organisms and human health. For example, DMAC wastewater usually contains high concentrations of organic matter, which is difficult to directly biodegrade; DMAC molecular structure is stable, and traditional biological treatment methods are not effective. At present, common treatment methods include iron-carbon-Fenton oxidation, coagulation sedimentation, anaerobic biochemical treatment, etc., but these methods have problems such as high treatment cost and low efficiency. Therefore, dimethylacetamide wastewater is also treated by resin adsorption.

[0003] The existing resin adsorption treatment of dimethylacetamide wastewater has the problem of limited adsorption capacity. As mentioned in patent publication CN118005864A, in the prior art, there are many disadvantages in the preparation method of N, N-dimethylacetamide waste gas adsorption resin, including that the prepared adsorption resin contains impurities that affect the adsorption capacity of N, N-dimethylacetamide waste gas, etc. The solution proposed in the above patent is to regulate the production process parameters of the preparation of dimethylacetamide adsorption resin, so as to achieve the improvement of dimethylacetamide adsorption capacity. However, if you want to greatly improve the adsorption of dimethylacetamide, the best way is to make the resin have selective adsorption capacity for dimethylacetamide, thereby improving the adsorption of dimethylacetamide while reducing the adsorption of other impurities, and cooperate with other technologies to treat dimethylacetamide wastewater in steps, so as to ensure the overall efficiency of wastewater treatment and ensure that the wastewater reaches a higher purification standard. Therefore, the present invention provides a resin with selective adsorption of dimethylacetamide, which improves the adsorption capacity of dimethylacetamide when the resin treats dimethylacetamide wastewater, and is combined with electro-oxidation to solve the problems existing in the above prior art. Summary of the invention

[0004] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for treating dimethylacetamide wastewater by combining resin and electro-oxidation.

[0005] A method for treating dimethylacetamide wastewater by combining resin and electro-oxidation comprises the following steps: S1: Crosslinking of lignocellulose and styrene particles The lignocellulose is mixed with deionized water, heated, and then potassium persulfate, sodium dodecyl sulfate and styrene monomer are added to obtain lignocellulose styrene cross-linked powder after reaction; S2: Preparation of lignocellulose / vinylpyridine modified resin The lignocellulose styrene crosslinked powder and vinyl pyridine monomer are added to 1,2-dichloroethane to swell, and then anhydrous ferric chloride, divinylbenzene crosslinking agent and initiator are added to react to obtain lignocellulose / vinyl pyridine modified resin; S3: Preparation of acetamide adsorption resin Extracting the lignocellulose / vinyl pyridine modified resin to obtain a substrate resin, adding the substrate resin and 1,2-dichloroethane into a reaction flask to swell, and then adding N-methylacetamide and anhydrous ferric chloride to react to obtain an acetamide adsorption resin; S4: Combined treatment of dimethylacetamide wastewater with resin and electro-oxidation The dimethylacetamide wastewater is adsorbed by acetamide adsorption resin to obtain primary treated wastewater, the primary treated wastewater is degraded under the action of an electric field to obtain degraded wastewater, the precipitate is removed from the degraded wastewater, and the resin and electro-oxidation combined treatment of the dimethylacetamide wastewater is completed.

[0006] Furthermore, step S1 of cross-linking lignocellulose and styrene particles comprises the following steps: S1.1: Mix lignocellulose and deionized water at a solid-liquid ratio of (1-3) g: 20 mL, heat to 80-90 °C, then stir at 300-350 r / min for 30-35 min, add 3-5% potassium persulfate of the total mass of the system, and keep stirring for 15-20 min; S1.2: Then add 2-3% of the total mass of the system sodium dodecyl sulfate, and then add styrene monomer equal to the mass of wood cellulose, maintain the temperature at 80-90°C, and introduce nitrogen, let the reaction stand for 3-4 hours, then cool to room temperature 22-24°C, precipitate the product and filter, wash, and dry in an oven at 60-65°C to constant weight to obtain wood cellulose styrene cross-linked powder.

[0007] Furthermore, step S2 prepares the lignocellulose / vinyl pyridine modified resin, comprising the following steps: S2.1: Add 2-2.4 parts by mass of wood cellulose styrene crosslinked powder and 1.2-2 parts by mass of vinyl pyridine monomer to 30-40 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300-350 r / min, and swell at room temperature for 12-13 hours; S2.2: Then weigh 4-8 parts by mass of anhydrous ferric chloride, 6-9 parts by mass of divinylbenzene crosslinker and 0.5-2 parts by mass of initiator, add them to the reaction system, raise the temperature to 50-60°C, react for 2-2.5 hours, raise the system temperature to 80-85°C, react for 12-13 hours, maintain a nitrogen environment during the entire reaction process, stop the reaction and cool to room temperature, filter and wash with methanol until the filtrate is colorless, dry the product at 60-65°C in a drying oven to constant weight, and obtain lignocellulose / vinyl pyridine modified resin.

[0008] Furthermore, step S3 prepares acetamide adsorption resin, comprising the following steps: S3.1: Place the lignocellulose / vinylpyridine modified resin in a Soxhlet extractor, extract with 90-95wt% ethanol for 5-6h, cool, take out and dry, transfer to a vacuum drying oven, dry at 60-65℃ to constant weight, store in a sealed bag, and obtain a substrate resin; S3.2: Add 20-25 parts by mass of substrate resin and 30-40 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 8-9 hours, then add 2-3 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 300-350r / min for 10-20min, after the N-methylacetamide is dissolved, add 5-8 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 300-350r / min for 2-2.5h, then heat the system to 80-85°C and reflux for 12-13h; S3.3: After the reaction is completed, cool to room temperature 22-24°C, filter, wash with water, place in a Soxhlet extractor and extract with anhydrous ethanol for 12-13 hours, cool, take out and dry, then transfer to a vacuum drying oven, vacuum dry at 40-45°C to constant weight to obtain acetamide adsorption resin.

[0009] Furthermore, in step S4, the resin and electro-oxidation combined treatment of dimethylacetamide wastewater comprises the following steps: S4.1: Filter the dimethylacetamide wastewater to remove suspended solids, and then pass it through acetamide adsorption resin at a flow rate of 0.5-3BV / h for an adsorption time of 24-25h to obtain primary treated wastewater; S4.2: Adjust the pH value of the primary treated wastewater to 2-4, use an electrocatalytic carbon membrane reactor, and perform synergistic degradation in combination with persulfate, with a reaction time of 30-60 minutes, degrade the primary treated wastewater under the action of an electric field to obtain degraded wastewater; S4.3: The degraded wastewater is passed through a sedimentation tank to remove the sediment and complete the combined resin and electro-oxidation treatment of dimethylacetamide wastewater.

[0010] Furthermore, the initiator is specifically azobisisobutyl cyanide.

[0011] Furthermore, the anode of the electrocatalytic carbon membrane reactor is titanium-based, the cathode is carbon steel, and the current density of the electrocatalytic carbon membrane reactor is 10-50 mA / cm 2 , the voltage is 10-20V.

[0012] Furthermore, the sulfate is specifically sodium persulfate.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention crosslinks lignocellulose with styrene and then further crosslinks with vinyl pyridine monomer to form a multidimensional crosslinked network resin with vinyl pyridine as a substrate and lignocellulose and styrene grafted together. Such a multidimensional crosslinked network structure gives the resin a high degree of crosslinking and good mechanical properties, i.e., an ultra-high crosslinked resin. The ultra-high crosslinked resin can provide a large number of adsorption sites, thereby significantly improving the adsorption efficiency of dimethylacetamide. In addition, the groups in vinyl pyridine can be introduced into the resin as functional groups, and lignocellulose contains active groups. After crosslinking, these groups can synergize with the pyridine ring to further enhance the adsorption capacity of dimethylacetamide.

[0014] 2. The present invention cross-links the acetamide group of N-methylacetamide to the vinyl pyridine resin, so that the vinyl pyridine resin has an acetamide group. The presence of the N-methylacetamide group increases the surface polarity of the resin, thereby improving the adsorption capacity for polar organic matter. Moreover, after the N-methylacetamide is combined with the vinyl pyridine, the structure of the resin is optimized, and more adsorption sites can be provided, thereby improving the adsorption efficiency. The functional groups in dimethylacetamide and the functional groups on the resin can be adsorbed through interaction, thereby improving the adsorption capacity of the resin for dimethylacetamide.

[0015] 3. The present invention combines cellulose with styrene, and the cross-linking reaction between cellulose and styrene can significantly improve the interfacial compatibility of the two by modifying styrene with cellulose. The components in cellulose can be combined with styrene through chemical bonds, thereby reducing the repulsion between interfaces and enhancing the bonding performance between interfaces, thereby assisting the subsequent steps to form a multi-dimensional network structure and a super-cross-linked resin. In addition, cellulose is a natural, renewable biomass material with a wide range of sources and low prices. Using cellulose to modify styrene particles can reduce dependence on petroleum-based materials, reduce production costs, and reduce environmental impact.

[0016] 4. The present invention combines resin adsorption with electro-oxidation to treat dimethylacetamide wastewater. The combined treatment of resin adsorption and electro-oxidation can give full play to the advantages of both and achieve complementarity. Resin adsorption can be used as a pretreatment step for electro-oxidation treatment to first remove most of the adsorbable pollutants in the wastewater and reduce the initial concentration of the wastewater. Electro-oxidation can further degrade the difficult-to-degrade organic matter remaining after resin adsorption and decompose it into harmless small molecules, thereby achieving a more thorough purification effect. The synergistic effect of resin adsorption and electro-oxidation can effectively improve the overall efficiency of wastewater treatment and ensure that the wastewater reaches a higher purification standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0018] Figure 1 This is a flow chart of a method for combined treatment of dimethylacetamide wastewater by resin and electro-oxidation adopted in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a detailed description of a resin and electro-oxidation combined treatment method for dimethylacetamide wastewater provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for a more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0020] Example 1: A method for treating dimethylacetamide wastewater by combining resin and electro-oxidation, such as Figure 1 As shown, the following steps are included: S1: Crosslinking of lignocellulose and styrene particles S1.1: Mix lignocellulose and deionized water at a solid-liquid ratio of 1 g:20 mL, heat to 80 °C, then stir at 300 r / min for 30 min, add 3% potassium persulfate of the total mass of the system, and keep stirring for 15 min; S1.2: Then add 2% of the total mass of the system sodium dodecyl sulfate, and then add styrene monomer equal to the mass of wood cellulose, maintain the temperature at 80°C, and introduce nitrogen. Let the reaction stand for 3 hours, then cool to room temperature 22°C, precipitate the product and filter, wash, and dry in an oven at 60°C to constant weight to obtain wood cellulose styrene cross-linked powder.

[0021] S2: Preparation of lignocellulose / vinylpyridine modified resin S2.1: Add 2 parts by mass of wood cellulose styrene crosslinked powder and 1.2 parts by mass of vinyl pyridine monomer to 30 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300 r / min, and swell at room temperature for 12 hours; S2.2: Then weigh 4 parts by mass of anhydrous ferric chloride, 6 parts by mass of divinylbenzene crosslinker and 0.5 parts by mass of initiator azobisisobutyl cyanide and add them to the reaction system, raise the temperature to 50°C, react for 2 hours, raise the system temperature to 80°C, react for 12 hours, maintain a nitrogen environment during the entire reaction process, stop the reaction and cool to room temperature, filter and wash with methanol until the filtrate is colorless, and dry the product in a drying oven at 60°C to constant weight to obtain lignocellulose / vinyl pyridine modified resin.

[0022] S3: Preparation of acetamide adsorption resin S3.1: Place the lignocellulose / vinylpyridine modified resin in a Soxhlet extractor, extract with 90 wt% ethanol for 5 h, cool, take out and dry, transfer to a vacuum drying oven, dry at 60 °C to constant weight, and store in a sealed bag to obtain a substrate resin; S3.2: Add 20 parts by mass of substrate resin and 30 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 8 hours, then add 2 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 300 r / min for 10 minutes, after N-methylacetamide is dissolved, add 5 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 300 r / min for 2 hours, then heat the system to 80°C and reflux for 12 hours; S3.3: After the reaction is completed, cool to room temperature 22°C, filter, wash with water, place in a Soxhlet extractor and extract with anhydrous ethanol for 12 hours, cool, take out and dry, then transfer to a vacuum drying oven, vacuum dry at 40°C to constant weight to obtain acetamide adsorption resin.

[0023] S4: Combined treatment of dimethylacetamide wastewater with resin and electro-oxidation S4.1: Filter the dimethylacetamide wastewater to remove suspended solids, and then pass it through acetamide adsorption resin at a flow rate of 0.5 BV / h for an adsorption time of 24 hours to obtain primary treated wastewater; S4.2: The pH value of the primary treated wastewater was adjusted to 2, and an electrocatalytic carbon membrane reactor was used to carry out synergistic degradation in combination with persulfate and sodium peroxydisulfate. The reaction time was 30 min. The anode of the electrocatalytic carbon membrane reactor was titanium-based, the cathode was carbon steel, and the current density of the electrocatalytic carbon membrane reactor was 10 mA / cm 2 , the voltage is 10V, and the primary treated wastewater is degraded under the action of the electric field to obtain degraded wastewater; S4.3: The degraded wastewater is passed through a sedimentation tank to remove the sediment and complete the combined resin and electro-oxidation treatment of dimethylacetamide wastewater.

[0024] Example 2: A method for treating dimethylacetamide wastewater by combining resin and electro-oxidation, such as Figure 1 As shown, the following steps are included: S1: Crosslinking of lignocellulose and styrene particles S1.1: Mix lignocellulose and deionized water at a solid-liquid ratio of 1 g:20 mL, heat to 90 °C, then stir at 350 r / min for 35 min, add 5% potassium persulfate of the total mass of the system, and keep stirring for 20 min; S1.2: Then add sodium dodecyl sulfate in an amount of 2% of the total mass of the system, and then add styrene monomer in an amount equal to the mass of wood cellulose, maintain the temperature at 90°C, and introduce nitrogen. Let the reaction stand for 4 hours, then cool to room temperature 24°C, precipitate the product, filter it, wash it, and dry it in an oven at 65°C to constant weight to obtain wood cellulose styrene cross-linked powder.

[0025] S2: Preparation of lignocellulose / vinylpyridine modified resin S2.1: Add 2 parts by mass of wood cellulose styrene crosslinked powder and 1.2 parts by mass of vinyl pyridine monomer to 30 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 350 r / min, and swell at room temperature for 12 hours; S2.2: Then weigh 4 parts by mass of anhydrous ferric chloride, 6 parts by mass of divinylbenzene crosslinker and 0.5 parts by mass of initiator azobisisobutyl cyanide and add them to the reaction system, raise the temperature to 60°C, react for 2.5 hours, raise the system temperature to 85°C, react for 13 hours, maintain a nitrogen environment during the entire reaction process, stop the reaction and cool to room temperature, filter and wash with methanol until the filtrate is colorless, and dry the product at 65°C in a drying oven to constant weight to obtain cellulose / vinyl pyridine modified resin.

[0026] S3: Preparation of acetamide adsorption resin S3.1: Place the lignocellulose / vinylpyridine modified resin in a Soxhlet extractor, extract with 95 wt% ethanol for 6 h, cool, take out and dry, transfer to a vacuum drying oven, dry at 65 °C to constant weight, and store in a sealed bag to obtain a substrate resin; S3.2: Add 25 parts by mass of substrate resin and 40 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 9 hours, then add 3 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 350 r / min for 20 minutes, after the N-methylacetamide is dissolved, add 5 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 350 r / min for 2.5 hours, then heat the system to 85°C and reflux for 13 hours; S3.3: After the reaction is completed, cool to room temperature (22°C), filter, wash with water, place in a Soxhlet extractor and extract with anhydrous ethanol for 13 hours, cool, take out and dry, then transfer to a vacuum drying oven, vacuum dry at 45°C to constant weight to obtain acetamide adsorption resin.

[0027] S4: Combined treatment of dimethylacetamide wastewater with resin and electro-oxidation S4.1: Filter the dimethylacetamide wastewater to remove suspended solids, and then pass it through acetamide adsorption resin at a flow rate of 0.5 BV / h for an adsorption time of 25 hours to obtain primary treated wastewater; S4.2: The pH value of the primary treated wastewater was adjusted to 2, and an electrocatalytic carbon membrane reactor was used to carry out synergistic degradation in combination with persulfate and sodium peroxydisulfate. The reaction time was 60 min. The anode of the electrocatalytic carbon membrane reactor was titanium-based, the cathode was carbon steel, and the current density of the electrocatalytic carbon membrane reactor was 50 mA / cm 2 , the voltage is 20V, and the primary treated wastewater is degraded under the action of the electric field to obtain degraded wastewater; S4.3: The degraded wastewater is passed through a sedimentation tank to remove the sediment and complete the combined resin and electro-oxidation treatment of dimethylacetamide wastewater.

[0028] Example 3: A method for treating dimethylacetamide wastewater by combining resin and electro-oxidation, such as Figure 1 As shown, the following steps are included: S1: Crosslinking of lignocellulose and styrene particles S1.1: Mix lignocellulose and deionized water at a solid-liquid ratio of 3 g:20 mL, heat to 80 °C, then stir at 300 r / min for 30 min, add 5% potassium persulfate of the total mass of the system, and keep stirring for 15 min; S1.2: Then add sodium dodecyl sulfate in an amount of 3% of the total mass of the system, and then add styrene monomer in an amount equal to the mass of the wood cellulose, maintain the temperature at 80°C, and introduce nitrogen. Let the reaction stand for 3 hours, then cool to room temperature 22°C, precipitate the product, filter it, wash it, and dry it in an oven at 60°C to constant weight to obtain wood cellulose styrene cross-linked powder.

[0029] S2: Preparation of lignocellulose / vinylpyridine modified resin S2.1: Add 2.4 parts by mass of wood cellulose styrene crosslinked powder and 2 parts by mass of vinyl pyridine monomer to 40 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300 r / min, and swell at room temperature for 12 hours; S2.2: Then weigh 8 parts by mass of anhydrous ferric chloride, 9 parts by mass of divinylbenzene crosslinker and 2 parts by mass of initiator azobisisobutyl cyanide and add them to the reaction system, raise the temperature to 50°C, react for 2 hours, raise the system temperature to 80°C, react for 12 hours, maintain a nitrogen environment during the entire reaction process, stop the reaction and cool to room temperature, filter and wash with methanol until the filtrate is colorless, and dry the product in a drying oven at 60°C to constant weight to obtain lignocellulose / vinyl pyridine modified resin.

[0030] S3: Preparation of acetamide adsorption resin S3.1: Place the lignocellulose / vinylpyridine modified resin in a Soxhlet extractor, extract with 90 wt% ethanol for 5 h, cool, take out and dry, transfer to a vacuum drying oven, dry at 60 °C to constant weight, and store in a sealed bag to obtain a substrate resin; S3.2: Add 25 parts by mass of substrate resin and 40 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 8 hours, then add 3 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 300 r / min for 10 minutes, after the N-methylacetamide is dissolved, add 8 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 300 r / min for 2 hours, then heat the system to 80°C and reflux for 12 hours; S3.3: After the reaction is completed, cool to room temperature 22°C, filter, wash with water, place in a Soxhlet extractor and extract with anhydrous ethanol for 12 hours, cool, take out and dry, then transfer to a vacuum drying oven, vacuum dry at 40°C to constant weight to obtain acetamide adsorption resin.

[0031] S4: Combined treatment of dimethylacetamide wastewater with resin and electro-oxidation S4.1: Filter the dimethylacetamide wastewater to remove suspended solids, and then pass it through acetamide adsorption resin at a flow rate of 0.5 BV / h for an adsorption time of 24 hours to obtain primary treated wastewater; S4.2: The pH value of the primary treated wastewater was adjusted to 2, and an electrocatalytic carbon membrane reactor was used to carry out synergistic degradation in combination with persulfate and sodium peroxydisulfate. The reaction time was 30 min. The anode of the electrocatalytic carbon membrane reactor was titanium-based, the cathode was carbon steel, and the current density of the electrocatalytic carbon membrane reactor was 10 mA / cm 2 , the voltage is 10V, and the primary treated wastewater is degraded under the action of the electric field to obtain degraded wastewater; S4.3: The degraded wastewater is passed through a sedimentation tank to remove the sediment and complete the combined resin and electro-oxidation treatment of dimethylacetamide wastewater.

[0032] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that, in step S2.1, instead of adding wood cellulose styrene cross-linked powder, styrene is added, specifically: "S2.1: Add 2 parts by mass of styrene and 1.2 parts by mass of vinyl pyridine monomer to 30 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300 r / min, and swell at room temperature for 12 hours", and the other steps remain unchanged.

[0033] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that, in step S2.1, instead of adding wood cellulose styrene cross-linked powder, wood cellulose is added, specifically: "S2.1: Add 2 parts by mass of wood cellulose and 1.2 parts by mass of vinyl pyridine monomer to 30 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300 r / min, and swell at room temperature for 12 hours", and the other steps remain unchanged.

[0034] Comparative Example 3: Compared with Example 1, the difference of Comparative Example 3 is that no wood cellulose styrene cross-linked powder is added in step S2.1, specifically: "S2.1: add 1.2 parts by mass of vinyl pyridine monomer to 30 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300 r / min, and swell at room temperature for 12 hours; S2.2: Then, 4 parts by mass of anhydrous ferric chloride, 6 parts by mass of divinylbenzene crosslinking agent and 0.5 parts by mass of initiator azobisisobutyl cyanide were weighed and added into the reaction system, the temperature was raised to 50°C, the reaction was carried out for 2 hours, the system temperature was raised to 80°C, the reaction was carried out for 12 hours, a nitrogen environment was maintained during the entire reaction process, the reaction was stopped and cooled to room temperature, the filtrate was filtered and washed with methanol until the filtrate was colorless, and the product was dried in a drying oven at 60°C to constant weight to obtain a "vinyl pyridine resin", the lignocellulose / vinyl pyridine modified resin in step S3 was replaced by the vinyl pyridine resin, and the other steps remained unchanged.

[0035] Comparative Example 4: Compared with Example 1, the difference of Comparative Example 4 is that N-methylacetamide is not added in step S3.2, specifically "S3.2: add 20 parts by mass of substrate resin and 30 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 8 hours, then add 2 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 300 r / min for 10 minutes, after N-methylacetamide is dissolved, add 5 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 300 r / min for 2 hours, then heat the system to 80°C, and reflux for 12 hours", and the other steps remain unchanged.

[0036] Comparative Example 5: Compared with Example 1, the difference of Comparative Example 5 is that the dimethylacetamide wastewater is directly subjected to electro-oxidation treatment, specifically: "The pH value of the dimethylacetamide wastewater is adjusted to 2, and an electrocatalytic carbon membrane reactor is used to carry out synergistic degradation in combination with persulfate. The reaction time is 30 minutes. The dimethylacetamide wastewater is degraded under the action of an electric field to obtain degraded wastewater. The degraded wastewater is passed through a sedimentation tank to remove the precipitate, and the electro-oxidation treatment is completed."

[0037] Comparative Example 6: Compared with Example 1, the difference of Comparative Example 6 is that the dimethylacetamide wastewater is directly subjected to resin adsorption treatment, specifically: "the dimethylacetamide wastewater is filtered to remove suspended matter, and then passed through acetamide adsorption resin at a flow rate of 0.5BV / h for 24 hours to complete the resin adsorption treatment."

[0038] A total of 9 L of dimethylacetamide wastewater generated in the production process of a chemical enterprise was taken, and it was evenly divided into 9 portions (1 L each) and recorded as Examples 1-3 and Comparative Examples 1-6, respectively. The dimethylacetamide content in the dimethylacetamide wastewater was determined by high performance liquid chromatography, and the dimethylacetamide content in the treated dimethylacetamide wastewater was treated by the methods of Examples 1-3 and Comparative Examples 1-6. After treatment, the dimethylacetamide content in the treated dimethylacetamide wastewater was determined again by high performance liquid chromatography, and the test data were organized into a table, as shown in Table 1.

[0039] Table 1 Dimethylacetamide content before treatment (%) Dimethylacetamide content after treatment (%) Example 1 35.42 1.26 Example 2 35.18 1.34 Example 3 35.61 1.24 Comparative Example 1 35.28 2.72 Comparative Example 2 35.63 3.84 Comparative Example 3 35.45 4.75 Comparative Example 4 35.14 6.83 Comparative Example 5 35.68 12.51 Comparative Example 6 35.49 11.67 As can be seen from Table 1, the dimethylacetamide contents of Examples 1, 2 and 3 are 1.26%, 1.34% and 1.24% respectively, and these values ​​are relatively close, indicating that the experimental conditions and treatment methods of the examples have certain stability and repeatability.

[0040] The dimethylacetamide content of Comparative Example 1 is 2.72%, indicating that after adding styrene without adding the wood cellulose styrene cross-linked powder, the treatment effect of dimethylacetamide becomes worse; the dimethylacetamide content of Comparative Example 2 is 3.84%, and the dimethylacetamide content of Comparative Example 3 is 4.75%. It can be seen that after removing wood cellulose and styrene, the adsorption effect of the resin is affected. When wood cellulose and styrene are added at the same time and vinyl pyridine is used as a substrate to prepare wood cellulose / vinyl pyridine modified resin, the dimethylacetamide content in the wastewater is significantly reduced, and it can be seen that the adsorption effect of the resin has been significantly improved.

[0041] The dimethylacetamide content of Comparative Example 4 is 6.83%, which means that without adding N-methylacetamide, there is no acetylamino group to cross-link with the resin, and the adsorption of the resin cannot be selective for dimethylacetamide, resulting in a significant reduction in the adsorption capacity for dimethylacetamide.

[0042] The dimethylacetamide contents of Comparative Examples 5 and 6 are 12.51% and 11.67% respectively. It can be seen that the combined treatment of resin adsorption and electro-oxidation can better reduce the dimethylacetamide content in dimethylacetamide wastewater and help wastewater treatment reach higher purification standards.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the present invention.

Claims

1. A method for treating dimethylacetamide wastewater by combining resin and electro-oxidation, characterized in that: The steps include: S1: Crosslinking of lignocellulose and styrene particles The lignocellulose is mixed with deionized water, heated, and then potassium persulfate, sodium dodecyl sulfate and styrene monomer are added to obtain lignocellulose styrene cross-linked powder after reaction; S2: Preparation of lignocellulose / vinylpyridine modified resin The lignocellulose styrene crosslinked powder and vinyl pyridine monomer are added to 1,2-dichloroethane to swell, and then anhydrous ferric chloride, divinylbenzene crosslinking agent and initiator are added to react to obtain lignocellulose / vinyl pyridine modified resin; S3: Preparation of acetamide adsorption resin Extracting the lignocellulose / vinyl pyridine modified resin to obtain a substrate resin, adding the substrate resin and 1,2-dichloroethane into a reaction flask to swell, and then adding N-methylacetamide and anhydrous ferric chloride to react to obtain an acetamide adsorption resin; S4: Combined treatment of dimethylacetamide wastewater with resin and electro-oxidation The dimethylacetamide wastewater is adsorbed by acetamide adsorption resin to obtain primary treated wastewater, the primary treated wastewater is degraded under the action of an electric field to obtain degraded wastewater, the precipitate is removed from the degraded wastewater, and the resin and electro-oxidation combined treatment of the dimethylacetamide wastewater is completed.

2. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 1 is characterized in that: Step S1: cross-linking lignocellulose and styrene particles, comprising the following steps: S1.1: Mix lignocellulose and deionized water at a solid-liquid ratio of (1-3) g: 20 mL, heat to 80-90 °C, then stir at 300-350 r / min for 30-35 min, add 3-5% potassium persulfate of the total mass of the system, and keep stirring for 15-20 min; S1.2: Then add 2-3% of the total mass of the system sodium dodecyl sulfate, and then add styrene monomer equal to the mass of wood cellulose, maintain the temperature at 80-90°C, and introduce nitrogen, let the reaction stand for 3-4 hours, then cool to room temperature 22-24°C, precipitate the product and filter, wash, and dry in an oven at 60-65°C to constant weight to obtain wood cellulose styrene cross-linked powder.

3. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 2 is characterized in that: Step S2 is to prepare a lignocellulose / vinyl pyridine modified resin, comprising the following steps: S2.1: Add 2-2.4 parts by mass of wood cellulose styrene crosslinked powder and 1.2-2 parts by mass of vinyl pyridine monomer to 30-40 parts by mass of 1,2-dichloroethane, maintain mechanical stirring at 300-350 r / min, and swell at room temperature for 12-13 hours; S2.2: Then weigh 4-8 parts by mass of anhydrous ferric chloride, 6-9 parts by mass of divinylbenzene crosslinker and 0.5-2 parts by mass of initiator, add them to the reaction system, raise the temperature to 50-60°C, react for 2-2.5 hours, raise the system temperature to 80-85°C, react for 12-13 hours, maintain a nitrogen environment during the entire reaction process, stop the reaction and cool to room temperature, filter and wash with methanol until the filtrate is colorless, dry the product at 60-65°C in a drying oven to constant weight, and obtain lignocellulose / vinyl pyridine modified resin.

4. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 3 is characterized in that: Step S3 prepares acetamide adsorption resin, comprising the following steps: S3.1: Place the lignocellulose / vinylpyridine modified resin in a Soxhlet extractor, extract with 90-95wt% ethanol for 5-6h, cool, take out and dry, transfer to a vacuum drying oven, dry at 60-65℃ to constant weight, store in a sealed bag, and obtain a substrate resin; S3.2: Add 20-25 parts by mass of substrate resin and 30-40 parts by mass of 1,2-dichloroethane to the reaction bottle, swell for 8-9 hours, then add 2-3 parts by mass of N-methylacetamide to the reaction bottle, stir at a speed of 300-350r / min for 10-20min, after the N-methylacetamide is dissolved, add 5-8 parts by mass of anhydrous ferric chloride, continue to stir at a speed of 300-350r / min for 2-2.5h, then heat the system to 80-85°C and reflux for 12-13h; S3.3: After the reaction is completed, cool to room temperature 22-24°C, filter, wash with water, place in a Soxhlet extractor and extract with anhydrous ethanol for 12-13 hours, cool, take out and dry, then transfer to a vacuum drying oven, vacuum dry at 40-45°C to constant weight to obtain acetamide adsorption resin.

5. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 4 is characterized in that: Step S4: The resin and electro-oxidation combined treatment of dimethylacetamide wastewater comprises the following steps: S4.1: Filter the dimethylacetamide wastewater to remove suspended solids, and then pass it through acetamide adsorption resin at a flow rate of 0.5-3BV / h for an adsorption time of 24-25h to obtain primary treated wastewater; S4.2: Adjust the pH value of the primary treated wastewater to 2-4, use an electrocatalytic carbon membrane reactor, and perform synergistic degradation in combination with persulfate, with a reaction time of 30-60 minutes, degrade the primary treated wastewater under the action of an electric field to obtain degraded wastewater; S4.3: The degraded wastewater is passed through a sedimentation tank to remove the sediment and complete the combined resin and electro-oxidation treatment of dimethylacetamide wastewater.

6. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 3 is characterized in that: The initiator is specifically azobisisobutyl cyanide.

7. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 5 is characterized in that: The anode of the electrocatalytic carbon membrane reactor is titanium-based, the cathode is carbon steel, and the current density of the electrocatalytic carbon membrane reactor is 10-50mA / cm 2 , the voltage is 10-20V.

8. The resin and electro-oxidation combined treatment method for dimethylacetamide wastewater according to claim 5 is characterized in that: The sulfate is specifically sodium peroxodisulfate.

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