Deep oxidation digestion method for sewage containing metallic paint

Abstract

The invention discloses a deep oxidation digestion method for sewage containing metallic paint, and belongs to the technical field of sewage treatment.The deep oxidation digestion method comprises the following steps that firstly, a hydrochloric acid solution with the mass fraction of 10% is used for adjusting the pH of the sewage containing the metallic paint, then a Fenton reagent is added, the system is adjusted to be neutral, and oxidized sewage is prepared; step 2, adding a water treatment agent into the oxidized sewage, stirring for 3-5 minutes at the rotating speed of 100-200r / min under illumination, standing and precipitating for 1-1.5 hours, and carrying out sand filtration to finish the treatment; advanced treatment is achieved through dual oxidation treatment of Fenton oxidation and water treatment agent treatment, the water treatment agent has a good treatment effect on metal paint-containing sewage, and when the water treatment agent acts on the sewage, on one hand, residual organic matter can be treated through photocatalytic performance of a modified carrier, and on the other hand, the residual organic matter can be treated; on the other hand, introduced quaternary ammonium salt cations can flocculate pollutant particles through electrostatic adsorption, and the treatment effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly relates to a method for deep oxidation and digestion of sewage containing metal paint. Background Art

[0002] The sewage containing metal paint has a very high COD, reaching 160,000 mg / L or even higher, a high content of harmful organic substances, is difficult to degrade, and also has a relatively high content of solid matter. For example, the paint-containing wastewater is difficult to treat. The paint-containing wastewater contains a large amount of suspended substances such as resin, surfactant, organic solvent and additives, and non-biodegradable macromolecular organic substances. The components of the pollutants are relatively complex and the recyclability is poor.

[0003] Currently, the traditional methods for treating paint-containing wastewater are dilution method and coagulation method. However, due to the excessive volume of the wastewater to be treated after dilution, a large amount of chemicals need to be added, so the treatment cost is relatively high and it is not suitable for large-scale application. The coagulation method is to directly add a coagulant and a flocculant to the paint-containing wastewater for coagulation treatment, but it is difficult to meet the safety discharge standard of the effluent quality. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method for deep oxidation and digestion of sewage containing metal paint.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A method for deep oxidation and digestion of sewage containing metal paint, comprising the following steps: The first step: adjusting the pH of the sewage containing metal paint to 4 - 4.5 with a 10% hydrochloric acid solution by mass fraction, then adding Fenton's reagent, stirring uniformly and oxidizing for 1 - 1.5 h, and then dropping 10% sodium hydroxide by mass fraction to adjust the system to neutrality to obtain the oxidized sewage; The second step: adding a water treatment agent to the oxidized sewage, stirring at a speed of 100 - 200 r / min under light for 3 - 5 min, standing and precipitating for 1 - 1.5 h, and then sand filtering to end the treatment.

[0006] The water treatment agent is prepared by the following steps: Step S1: adding tetrabutyl titanate to tetraethyl orthosilicate, stirring uniformly for 5 min, then adding triethanolamine, continuing to stir for 30 min, then slowly dropping tetraethylammonium hydroxide, stirring uniformly for 30 min, then aging at room temperature for 24 h. After the aging is completed, transfer it to an oven at 100 °C and dry for 24 h to obtain a gel. Then transfer it to a reaction kettle, hydrothermal react at 180 °C for 8 h, and then calcine at 550 - 600 °C for 12 h to obtain a catalytic support. Control the dosage ratio of tetrabutyl titanate, tetraethyl orthosilicate, triethanolamine and tetraethylammonium hydroxide to be 21.02 - 21.28 mL: 72 - 82 mL: 25.40 - 25.48 mL: 16.20 - 16.58 mL; In step S1, tetraethyl orthosilicate is used as the silicon source, triethanolamine as the template agent, and tetraethylammonium hydroxide as the auxiliary template agent. Through the hydrothermal synthesis method, Si-O bonds are gradually formed between the tetraethyl orthosilicate molecules, and finally a porous material with a three-dimensional mesoporous structure is synthesized. Tetrabutyl titanate is used as the titanium source, and titanium dioxide prepared by the sol-gel method is used as the photocatalytic component to form a catalytic carrier. This carrier uses the porous material as the carrier and titanium dioxide as the photocatalytic component. When used for sewage treatment, it can further treat the residual organic matter after Fenton oxidation and improve the removal effect of organic matter.

[0007] Step S2: Add the catalytic carrier to an ethanol aqueous solution with a volume fraction of 90%, add KH570, stir evenly for 15 - 30 min, then adjust the pH of the system until pH = 4, then let it stand for 1 h, heat up to 60 - 70 °C, stir evenly and react for 4 h. After the reaction, a modified catalytic carrier is obtained. Control the dosage ratio of the catalytic carrier, KH570, and the ethanol aqueous solution to be 1 - 2 g : 3 - 6 mL : 10 - 15 mL; In step S2, the surface of the catalytic carrier is modified by the silane coupling agent KH570, and carbon-carbon double bonds are introduced onto the surface of the catalytic carrier; Step S3: Add polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, and the modified catalytic carrier to deionized water, ultrasonically disperse for 30 min, heat up to 40 - 45 °C, add ammonium persulfate, and react for 20 - 24 h under a nitrogen atmosphere. After the reaction, a water treatment agent is obtained. Control the dosage ratio of polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, the modified catalytic carrier, ammonium persulfate, and deionized water to be 1 - 2 mmol : 1 - 2 mmol : 0.05 - 0.08 mmol : 2 - 3 g : 3 - 5 g : 0.03 - 0.05 mmol : 20 - 30 mL.

[0008] In step S3, polypropylene and methacryloyloxyethyltrimethylammonium chloride are used as monomers, polydimethyldiallylammonium chloride as the stabilizer, and ammonium persulfate as the initiator. The carbon-carbon double bonds on the polypropylene, methacryloyloxyethyltrimethylammonium chloride, and the modified catalytic carrier polymerize, and quaternary ammonium cations are introduced onto the surface of the modified catalytic carrier through polymerization to prepare a water treatment agent. When this water treatment agent acts on sewage, on the one hand, it can treat the residual organic matter through the photocatalytic performance of the modified carrier, and on the other hand, the introduced quaternary ammonium cations can flocculate pollutant particles through electrostatic adsorption to improve the treatment effect.

[0009] Furthermore, in the first step, the concentration of ferrous sulfate in the Fenton reagent is 1 - 1.2 g / L, and the concentration of hydrogen peroxide is 5 - 10 mL / L.

[0010] Further, the concentration of the water treatment agent in the second step is 1-2 g / L.

[0011] Advantages of the present invention: The present invention discloses a method for deep oxidation and digestion of sewage containing metal paint. Through dual oxidation treatment of Fenton oxidation and water treatment agent treatment, deep treatment is achieved, and good treatment effect on sewage containing metal paint is obtained. In the preparation process of the water treatment agent, tetraethyl orthosilicate is used as the silicon source, triethanolamine is used as the template agent, and tetraethylammonium hydroxide is used as the auxiliary template agent. Si-O bonds are gradually formed between the tetraethyl orthosilicate molecules through hydrothermal synthesis method, and finally a porous material with a three-dimensional mesoporous structure is synthesized. Using tetrabutyl titanate as the titanium source, titanium dioxide prepared by the sol-gel method is used as the photocatalytic component to form a catalytic carrier. The carrier uses the porous material as the carrier and titanium dioxide as the photocatalytic component. The surface of the catalytic carrier is modified by silane coupling agent KH570, and carbon-carbon double bonds are introduced on the surface of the catalytic carrier. Finally, ammonium persulfate is used as the initiator, and polypropylene, methacryloyloxyethyltrimethylammonium chloride and the carbon-carbon double bonds on the modified catalytic carrier are polymerized, and quaternary ammonium cations are introduced on the surface of the modified catalytic carrier through polymerization to prepare the water treatment agent. When the water treatment agent acts on sewage, on the one hand, it can treat the residual organic matter through the photocatalytic performance of the modified carrier, and on the other hand, the introduced quaternary ammonium cations can flocculate the pollutant particles through electrostatic adsorption to improve the treatment effect. Specific embodiments

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0013] Example 1: A method for deep oxidation and digestion of sewage containing metal paint, comprising the following steps: The first step: Adjust the pH of the sewage containing metal paint to 4 with a 10% hydrochloric acid solution by mass, then add Fenton reagent, stir evenly and oxidize for 1 h, and then add 10% sodium hydroxide by mass to adjust the system to neutrality to obtain the oxidized sewage. The second step: Add a water treatment agent to the oxidized sewage, stir at a speed of 100 r / min for 3 min under light, stand and precipitate for 1 h, and filter with sand to end the treatment.

[0014] In the first step, the concentration of ferrous sulfate in the Fenton reagent is 1 g / L, and the concentration of hydrogen peroxide is 5 mL / L.

[0015] In the second step, the concentration of the water treatment agent is 1 g / L.

[0016] The water treatment agent is prepared through the following steps: Step S1: Add tetrabutyl titanate to tetraethyl orthosilicate, stir evenly for 5 min, then add triethanolamine, continue stirring for 30 min, then slowly dropwise add tetraethylammonium hydroxide, stir evenly for 30 min, then age at room temperature for 24 h. After the aging is completed, transfer it to an oven at 100 °C and dry for 24 h to obtain a gel. Then transfer it to a reaction kettle, carry out hydrothermal treatment at 180 °C for 8 h, and then calcine at 550 °C for 12 h to obtain a catalytic carrier. Control the dosage ratio of tetrabutyl titanate, tetraethyl orthosilicate, triethanolamine and tetraethylammonium hydroxide to be 21.02 mL: 72 mL: 25.40 mL: 16.20 mL; Step S2: Add the catalytic carrier to an ethanol aqueous solution with a volume fraction of 90%, add KH570, stir evenly for 15 min, then adjust the pH of the system until pH = 4, then let it stand for 1 h, heat up to 60 °C, stir evenly and react for 4 h. After the reaction is completed, obtain a modified catalytic carrier. Control the dosage ratio of the catalytic carrier, KH570 and the ethanol aqueous solution to be 1 g: 3 mL: 10 mL; Step S3: Add polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate and the modified catalytic carrier to deionized water, ultrasonically disperse for 30 min, heat up to 40 °C, add ammonium persulfate, and react for 20 h under a nitrogen atmosphere. After the reaction is completed, obtain the water treatment agent. Control the dosage ratio of polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, the modified catalytic carrier, ammonium persulfate and deionized water to be 1 mmol: 1 mmol: 0.05 mmol: 2 g: 3 g: 0.03 mmol: 20 mL.

[0017] Example 2: A method for deep oxidation and digestion of sewage containing metal paint, including the following steps: The first step: Adjust the pH of the sewage containing metal paint to 4.5 with a 10% hydrochloric acid solution by mass, then add Fenton's reagent, stir evenly and oxidize for 1.2 h, then dropwise add 10% sodium hydroxide by mass to adjust the system to neutrality to obtain oxidized sewage; The second step: Add the water treatment agent to the oxidized sewage, stir at a speed of 150 r / min under light for 4 min, let it stand and precipitate for 1.2 h, and filter with sand to end the treatment.

[0018] In the first step, the concentration of ferrous sulfate in the Fenton's reagent is 1.1 g / L, and the concentration of hydrogen peroxide is 8 mL / L.

[0019] In the second step, the concentration of the water treatment agent is 1.5 g / L.

[0020] The water treatment agent is prepared through the following steps: Step S1: Add tetrabutyl titanate to tetraethyl orthosilicate, stir evenly for 5 min, then add triethanolamine, continue stirring for 30 min, then slowly dropwise add tetraethylammonium hydroxide, stir evenly for 30 min, then age at room temperature for 24 h. After the aging is completed, transfer it to an oven at 100 °C and dry for 24 h to obtain a gel. Then transfer it to a reaction kettle, hydrothermally react at 180 °C for 8 h and then calcine at 600 °C for 12 h to obtain a catalytic support. Control the dosage ratio of tetrabutyl titanate, tetraethyl orthosilicate, triethanolamine and tetraethylammonium hydroxide to be 21.20 mL: 78 mL: 25.45 mL: 16.40 mL; Step S2: Add the catalytic support to an ethanol aqueous solution with a volume fraction of 90%, add KH570, stir evenly for 20 min, then adjust the pH of the system until pH = 4, then let it stand for 1 h, raise the temperature to 65 °C, stir evenly and react for 4 h. After the reaction is completed, obtain a modified catalytic support. Control the dosage ratio of the catalytic support, KH570 and the ethanol aqueous solution to be 1.5 g: 5 mL: 12 mL; Step S3: Add polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate and the modified catalytic support to deionized water, ultrasonically disperse for 30 min, raise the temperature to 44 °C, add ammonium persulfate, and react for 22 h under a nitrogen atmosphere. After the reaction is completed, obtain a water treatment agent. Control the dosage ratio of polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, the modified catalytic support, ammonium persulfate and deionized water to be 1.5 mmol: 1.5 mmol: 0.06 mmol: 2.5 g: 4 g: 0.04 mmol: 25 mL.

[0021] Example 3: A method for deep oxidation digestion of sewage containing metal paint, comprising the following steps: First step: Adjust the pH of the sewage containing metal paint to 4.5 with a 10% hydrochloric acid solution by mass, then add Fenton's reagent, stir evenly and oxidize for 1.5 h, then dropwise add 10% sodium hydroxide by mass to adjust the system to neutrality to obtain oxidized sewage; Second step: Add the water treatment agent to the oxidized sewage, stir at a speed of 200 r / min under light for 5 min, let it stand and precipitate for 1.5 h, and filter with sand to end the treatment.

[0022] In the first step, the concentration of ferrous sulfate in the Fenton's reagent is 1.2 g / L, and the concentration of hydrogen peroxide is 10 mL / L.

[0023] In the second step, the concentration of the water treatment agent is 2 g / L.

[0024] The water treatment agent is prepared through the following steps: Step S1: Add tetrabutyl titanate to tetraethyl orthosilicate, stir evenly for 5 min, then add triethanolamine, continue stirring for 30 min, and then slowly dropwise add tetraethylammonium hydroxide, stir evenly for 30 min, then age at room temperature for 24 h. After the aging is completed, transfer it to an oven at 100 °C and dry for 24 h to obtain a gel. Then transfer it to a reaction kettle, hydrothermally react at 180 °C for 8 h, and then calcine at 600 °C for 12 h to obtain a catalytic support. Control the dosage ratio of tetrabutyl titanate, tetraethyl orthosilicate, triethanolamine, and tetraethylammonium hydroxide to be 21.28 mL: 82 mL: 25.48 mL: 16.58 mL; Step S2: Add the catalytic support to an ethanol aqueous solution with a volume fraction of 90%, add KH570, stir evenly for 30 min, then adjust the pH of the system until pH = 4, then let it stand for 1 h, heat up to 70 °C, stir evenly and react for 4 h. After the reaction is completed, obtain a modified catalytic support. Control the dosage ratio of the catalytic support, KH570, and the ethanol aqueous solution to be 2 g: 6 mL: 15 mL; Step S3: Add polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, and the modified catalytic support to deionized water, ultrasonically disperse for 30 min, heat up to 45 °C, add ammonium persulfate, and react under a nitrogen atmosphere for 24 h. After the reaction is completed, obtain a water treatment agent. Control the dosage ratio of polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, the modified catalytic support, ammonium persulfate, and deionized water to be 2 mmol: 2 mmol: 0.08 mmol: 3 g: 5 g: 0.05 mmol: 30 mL.

[0025] Comparative Example 1: Compared with Example 1, this comparative example did not add a water treatment agent, and the rest was the same as Example 1.

[0026] Treat the standard wastewater according to the treatment methods disclosed in Examples 1 - 3 and Comparative Example 1. The results of the treated wastewater are shown in Table 1 below: Table 1 It can be seen from Table 1 above that Examples 1 - 3 of the present invention have excellent purification treatment effects on sewage.

[0027] The above content is only an example and explanation of the concept of the present invention. Those skilled in the art of this technology make various modifications or supplements to the specific embodiments described or use similar methods for substitution. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. A method for deep oxidation and digestion of sewage containing metallic paint, characterized in that, It includes the following steps: The first step: Adjust the pH of the metal-containing paint wastewater to 4 - 4.5 with a 10% hydrochloric acid solution by mass fraction. Then add Fenton's reagent, stir evenly and oxidize for 1 - 1.5 h. After that, add 10% sodium hydroxide by mass fraction dropwise to adjust the system to neutrality, and obtain the oxidized wastewater; The second step: Add a water treatment agent to the oxidized wastewater, stir at a speed of 100 - 200 r / min for 3 - 5 min under light, let it stand and precipitate for 1 - 1.5 h, and then perform sand filtration to end the treatment; The water treatment agent is prepared through the following steps: Step S1: Add tetrabutyl titanate to tetraethyl orthosilicate, stir evenly for 5 min, then add triethanolamine, continue to stir for 30 min. After that, slowly add tetraethylammonium hydroxide dropwise and stir evenly for 30 min. Then age at room temperature for 24 h. After the aging is completed, transfer it to an oven at 100 °C and dry for 24 h to obtain a gel. Then transfer it to a reaction kettle, hydrothermally react at 180 °C for 8 h, and then calcine at 550 - 600 °C for 12 h to obtain a catalytic support; Step S2: Add the catalytic support to an ethanol aqueous solution with a volume fraction of 90%, add KH570, stir evenly for 15 - 30 min, then adjust the pH of the system, then let it stand for 1 h, heat up to 60 - 70 °C, stir evenly and react for 4 h. After the reaction is completed, obtain a modified catalytic support; Step S3: Add polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate and the modified catalytic support to deionized water, ultrasonically disperse for 30 min, heat up to 40 - 45 °C, add ammonium persulfate, and react for 20 - 24 h under a nitrogen atmosphere. After the reaction is completed, obtain the water treatment agent.

2. The method for deep oxidation digestion of sewage containing metallic paint according to claim 1, characterized in that, In the first step, the concentration of ferrous sulfate in the Fenton's reagent is 1 - 1.2 g / L, and the concentration of hydrogen peroxide is 5 - 10 mL / L.

3. A method for deep oxidation digestion of sewage containing metal paint according to claim 1, characterized in that, In the second step, the concentration of the water treatment agent is 1 - 2 g / L.

4. A method for deep oxidation and digestion of sewage containing metallic paint according to claim 1, characterized in that, In step S1, control the dosage ratio of tetrabutyl titanate, tetraethyl orthosilicate, triethanolamine and tetraethylammonium hydroxide to be 21.02 - 21.28 mL: 72 - 82 mL: 25.40 - 25.48 mL: 16.20 - 16.58 mL.

5. A method for deep oxidation digestion of sewage containing metal paint according to claim 1, characterized in that, In step S2, control the dosage ratio of the catalytic support, KH570 and the ethanol aqueous solution to be 1 - 2 g: 3 - 6 mL: 10 - 15 mL.

6. The method for deep oxidation and digestion of sewage containing metallic paint according to claim 1, characterized in that, In step S3, control the dosage ratio of polypropylene, methacryloyloxyethyltrimethylammonium chloride, polydimethyldiallylammonium chloride, ammonium sulfate, the modified catalytic support, ammonium persulfate and deionized water to be 1 - 2 mmol: 1 - 2 mmol: 0.05 - 0.08 mmol: 2 - 3 g: 3 - 5 g: 0.03 - 0.05 mmol: 20 - 30 mL.

7. A method for deep oxidation and digestion of sewage containing metal paint according to claim 1, characterized in that, In step S2, the pH of the system = 4.

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