Treatment method of triethylamine-containing wastewater

Abstract

The invention relates to a treatment method of triethylamine-containing wastewater. The treatment method comprises the following steps: S1, diluting the triethylamine-containing wastewater by adopting industrial treatment water; the triethylamine-containing wastewater is wastewater generated in a molecular sieve synthesis process; s2, adding a flocculating agent into the diluted wastewater, adjusting the pH value to be acidic, carrying out flocculation, and separating a precipitate from a supernatant; and S3, adjusting the pH value of the supernate to be alkaline, and carrying out wet oxidation treatment. According to the process route of raw water dilution, acidic flocculation and alkaline wet oxidation, the biodegradability of the triethylamine-containing wastewater is efficiently improved, and the environmental problems of high energy consumption, secondary pollution and the like caused by methods of distillation, extraction, incineration and the like are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a method for treating wastewater containing triethylamine. Background Art

[0002] In the production and preparation process of molecular sieve catalysts, raw materials such as triethylamine, silica sol, and alumina are usually added to participate in the reaction synthesis. Therefore, the generated wastewater contains a large amount of organic amines and other substances that are difficult to degrade and are toxic and harmful. If such wastewater is directly discharged without effective treatment, it will cause serious harm to the ecological environment.

[0003] Currently, the common treatment methods for such wastewater mainly include biological treatment and incineration treatment. However, due to the strong toxicity of the wastewater, if it is directly discharged into the sewage treatment device for biological treatment, it will cause a great impact on the treatment system, resulting in a large number of deaths of biological flora and seriously affecting the treatment effect; while the incineration treatment method needs to operate under high-temperature conditions above 800 °C, which not only has extremely high energy consumption, but also faces the problem of corrosion of combustion equipment by molten salts, and may also generate secondary pollutants such as nitrogen oxides, causing new harm to the environment.

[0004] In view of the limitations of the existing treatment methods, it is particularly urgent to develop an efficient, low-energy-consuming, safe and environmentally friendly treatment process for such wastewater, which has important practical significance for solving the environmental harm problem of the wastewater produced in the production of molecular sieve catalysts. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method for treating wastewater containing triethylamine.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for treating wastewater containing triethylamine, comprising the following steps:

[0008] S1. Dilute the wastewater containing triethylamine with industrial treated water;

[0009] The wastewater containing triethylamine is the wastewater generated during the synthesis of molecular sieves;

[0010] S2. Add a flocculant to the diluted wastewater, adjust the pH to acidic, perform flocculation, and separate the precipitate and the supernatant;

[0011] S3. Adjust the pH of the supernatant to alkaline and perform wet oxidation treatment.

[0012] A treatment method for wastewater containing triethylamine proposed by the present invention first dilutes the wastewater containing triethylamine to reduce the concentration of pollutants, providing a suitable pollutant load for subsequent flocculation precipitation and effectively improving the treatment effect of flocculation precipitation; then, under acidic conditions, most suspended impurities and inorganic pollutants (such as phosphate, silicate, alumina, etc.) are removed through flocculation precipitation, avoiding problems such as equipment scaling and blockage in the wet oxidation treatment stage and reducing the inhibitory effect of these pollutants (mainly acid radicals) on the wet oxidation reaction; finally, under alkaline conditions, the organic matter is oxidized and decomposed by wet oxidation treatment, thereby improving the biodegradability of the wastewater and paving the way for biochemical treatment. The process route of raw water dilution - acidic flocculation - alkaline wet oxidation of the present invention efficiently improves the biodegradability of the wastewater containing triethylamine and avoids environmental problems such as high energy consumption and secondary pollution caused by methods such as distillation, extraction, and incineration.

[0013] Preferably, in step S1, the industrial treated water is external sewage and / or desalted water.

[0014] Preferably, in step S1, the dilution multiple is 4 - 6 times.

[0015] Preferably, in step S2, the flocculant includes iron salt and polyacrylamide.

[0016] More preferably, based on the volume of the diluted wastewater, the addition amount of the iron salt is 20 - 40 g / L, and the addition amount of the polyacrylamide is 50 - 100 g / L.

[0017] Preferably, in step S2, the pH is adjusted to 3 - 4.

[0018] Preferably, in step S3, the conditions for the wet oxidation treatment are: the reaction pressure is 2.5 - 4.5 MPa, the reaction temperature is 130 - 240 °C, and the liquid hourly space velocity is 0.1 - 10 h -1 .

[0019] Preferably, in step S3, the pH is adjusted to 8 - 12.

[0020] Preferably, it further includes: performing biochemical treatment on the effluent after the wet oxidation treatment. Detailed implementation manners

[0021] 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. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0022] An embodiment of the present invention provides a method for treating wastewater containing triethylamine, comprising the following steps:

[0023] S1. Dilute the wastewater containing triethylamine with industrial treated water;

[0024] The wastewater containing triethylamine is the wastewater generated during the synthesis process of molecular sieve;

[0025] S2. Add a flocculant to the diluted wastewater, adjust the pH to acidic, perform flocculation, and separate the precipitate and the supernatant;

[0026] S3. Adjust the pH of the supernatant to alkaline and perform wet oxidation treatment.

[0027] In the present invention, before entering the wet oxidation treatment, the supernatant needs to be adjusted to an alkaline condition because, under alkaline conditions, the oxidation reaction activity of NH3 molecules in water is higher than that of NH4 + ions, which is more conducive to the oxidation reaction of NH3 to generate N2, promotes the shift of the oxidation reaction equilibrium towards the product direction, and improves the reaction conversion efficiency. In addition, the waste heat after the wet oxidation reaction can be recycled to increase the temperature of the raw water inlet, reduce the reaction heating time and energy consumption.

[0028] In a preferred embodiment of the present invention, in step S1, the industrial treated water is the externally discharged sewage and / or demineralized water. In the present invention, the externally discharged sewage refers to the wastewater generated during industrial production, which meets the national environmental protection discharge standards after treatment and is discharged into the external environment (such as rivers, lakes or municipal pipe networks); the demineralized water refers to the water from which dissolved salts (such as calcium, magnesium, sodium, chloride ions, etc.) are removed through a desalination process.

[0029] In a preferred embodiment of the present invention, in step S1, the dilution multiple is 4 - 6 times.

[0030] In a preferred embodiment of the present invention, in step S2, the flocculant includes iron salts and polyacrylamide. In the present invention, for example, the iron salts can be selected from compounds such as ferric chloride, ferric sulfate, etc., without particular limitation.

[0031] In a more preferred embodiment of the present invention, based on the volume of the diluted wastewater, the addition amount of the iron salt is 20 - 40 g / L, and the addition amount of polyacrylamide is 50 - 100 g / L. In the present invention, the iron salt will hydrolyze to generate Fe 3 + under acidic conditions, which plays a role in chemical precipitation (to remove phosphate and silicate radicals) and electro-neutralization (to remove alumina and other suspended impurities), destabilizes the colloidal particles, and forms large flocs in combination with the adsorption bridging effect of polyacrylamide, accelerating sedimentation. The preferred addition amount of the iron salt is 30 - 35 g / L, and the preferred addition amount of polyacrylamide is 70 - 80 g / L.

[0032] In a preferred embodiment of the present invention, in step S2, the pH is adjusted to 3-4.

[0033] In a preferred embodiment of the present invention, in step S3, the conditions for wet oxidation treatment are: the reaction pressure is 2.5-4.5 MPa, the reaction temperature is 130-240 °C, and the liquid hourly space velocity is 0.1-10 h -1 In a preferred embodiment of the present invention, in step S3, the pH is adjusted to 8-12.

[0034] In a preferred embodiment of the present invention, it further includes: subjecting the effluent after wet oxidation treatment to biochemical treatment.

[0035] Example 1

[0036] The wastewater containing triethylamine is the wastewater generated during the synthesis process of molecular sieve, showing light yellow. After analysis, the pH is 6.5, the COD is about 100000 mg / L, the total nitrogen is about 45000 mg / L, the phosphate radical is about 29700 mg / L, the silicate radical is about 823 mg / L, and the alumina is about 1862 mg / L.

[0037] A treatment method for wastewater containing triethylamine, comprising the following steps:

[0038] S1. Dilute the wastewater containing triethylamine 5 times with industrial treated water (effluent sewage).

[0039] S2. Add flocculants (35 g / L of ferric chloride and 75 g / L of polyacrylamide based on the volume of the diluted wastewater) to the diluted wastewater, and adjust the pH to 4 for flocculation, separating the precipitate and the supernatant.

[0040] S3. Adjust the pH of the supernatant to 9 for wet oxidation treatment, setting the reaction conditions: the reaction pressure is 4 MPa, the reaction temperature is 200 °C, and the liquid hourly space velocity is 2 h -1 , and introduce air with a stoichiometric ratio of 300%.

[0041] S4. Subject the effluent after wet oxidation treatment to biochemical treatment.

[0042] Example 2

[0043] The difference between this example and Example 1 is that in step S3, the pH of the supernatant is adjusted to 8. The other steps remain unchanged.

[0044] Example 3

[0045] The difference between this example and Example 1 is that in step S3, the pH of the supernatant is adjusted to 10. The other steps remain unchanged.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that in step S3, the pH of the supernatant was adjusted to 6. The remaining steps remained unchanged.

[0048] The effluent effects of step S2 and step S3 of Examples 1-3 and Comparative Example 1 were measured and recorded in Table 1.

[0049] Table 1

[0050]

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating triethylamine-containing wastewater, characterized in that: The following steps are involved: S1. Diluting the wastewater containing triethylamine with industrial treated water; The triethylamine-containing wastewater is wastewater generated during the synthesis of molecular sieves; S2, adding a flocculant to the diluted wastewater, adjusting the pH to acidic, performing flocculation, and separating the precipitate from the supernatant; S3, adjusting the pH of the supernatant to alkaline and performing wet oxidation treatment.

2. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S1, the industrial treated water is discharged sewage and / or desalted water.

3. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S1, the dilution multiple is 4-6 times.

4. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S2, the flocculant includes iron salt and polyacrylamide.

5. The method for treating triethylamine-containing wastewater as claimed in claim 4, wherein: Based on the volume of the diluted wastewater, the added amount of the iron salt is 20-40 g / L, and the added amount of the polyacrylamide is 50-100 g / L.

6. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S2, the pH is adjusted to 3-4.

7. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S3, the conditions of the wet oxidation treatment are: reaction pressure of 2.5-4.5 MPa, reaction temperature of 130-240°C, liquid hourly space velocity of 0.1-10 h -1 .

8. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: In step S3, the pH is adjusted to 8-12.

9. The method for treating triethylamine-containing wastewater as claimed in claim 1, wherein: Also includes: The effluent after the wet oxidation treatment is subjected to biochemical treatment.

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