A pretreatment method of organic wastewater containing an oxirane derivative

Abstract

The present application belongs to the technical field of wastewater treatment, and particularly relates to a pretreatment method of organic wastewater containing ethylene oxide derivatives. The method comprises the following steps: flocculation pretreatment; catalytic cracking reduction treatment; sending the organic wastewater containing ethylene oxide derivatives after the flocculation pretreatment into a catalytic cracking reactor to contact with a cracking reduction catalyst for reaction; electrocatalytic oxidation treatment; and filtration. Compared with the prior art, the present application has the following advantages: the catalytic cracking is used to open the ring and break the chain of the large molecular organic matters in the ethylene oxide derivative (EOD) wastewater, so that the large molecular organic matters are degraded into small molecular organic matters; and then the electrocatalytic oxidation technology is used to oxidize and degrade the small molecules. As a wastewater pretreatment technology, the present application has a high treatment effect on the ethylene oxide derivative (EOD) wastewater, and the treated organic wastewater can meet the indexes of subsequent biochemical treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a pretreatment method for organic wastewater containing an ethylene oxide derivative. BACKGROUND

[0002] Biochemical treatment is also called biological chemical treatment, and is abbreviated as biochemical method. The biochemical treatment method is the most widely used and relatively effective method for treating wastewater.

[0003] At present, direct biochemical treatment of raw water with high organic matter content, complex types and certain toxicity will cause impact on the organic matter treatment load. The wastewater cannot be directly treated by the biochemical method, otherwise the microorganisms will be inhibited from growth and reproduction, and even die. Therefore, a pretreatment process needs to be added before entering the biochemical tank to reduce the organic matter in the wastewater to an acceptable range for biochemical treatment, and then the biochemical reaction is more beneficial.

[0004] The existing pretreatment process before the biochemical tank is iron-carbon micro-electrolysis combined with Fenton combined oxidation method, which has good treatment effect on general wastewater. However, for organic wastewater containing an ethylene oxide (EO) derivative, because the wastewater contains a large amount of substances inhibiting biological growth, such as mercaptoacetic acid, thio-bis-ethanol and dithio-bis-ethanol sulfite, and some benzene ring structures that are difficult to oxidize, the traditional method has poor treatment effect, and cannot reduce the organic matter in the wastewater to an acceptable range for biochemical treatment, which is not conducive to the biochemical reaction. SUMMARY

[0005] To solve one of the above problems, the application provides a pretreatment method for organic wastewater containing an ethylene oxide derivative, which solves the problem that the existing iron-carbon micro-electrolysis combined with Fenton combined oxidation method for treating organic wastewater containing an ethylene oxide (EO) derivative has poor treatment effect because the wastewater contains a large amount of substances inhibiting biological growth, such as mercaptoacetic acid, thio-bis-ethanol and dithio-bis-ethanol sulfite, and some benzene ring structures that are difficult to oxidize, and cannot reduce the organic matter in the wastewater to an acceptable range for biochemical treatment, which is not conducive to the biochemical reaction.

[0006] The technical scheme of the application is as follows:

[0007] The application discloses a pretreatment method for organic wastewater containing an ethylene oxide derivative, characterized in that the method comprises the following steps:

[0008] (a) flocculation pretreatment: the organic wastewater containing an ethylene oxide derivative is added to a flocculation tank, the pH is adjusted, and flocculation pretreatment is performed to remove macromolecular organic matter and particulate matter in the organic wastewater containing an ethylene oxide derivative;

[0009] (b) catalytic cracking reduction treatment: the organic wastewater containing ethylene oxide derivatives after flocculation pretreatment is sent into a catalytic cracking reactor to react with a cracking reduction catalyst, the reaction pH is controlled to be 3.5, the reaction does not need stirring, and the reaction time is 120-240 min;

[0010] (c) electro-catalytic oxidation treatment: the pH of the organic wastewater containing ethylene oxide derivatives after the catalytic cracking reduction treatment is increased to neutral, and then an electro-catalytic oxidation reaction device is used for electro-catalytic oxidation reaction;

[0011] (d) filtration: the pH of the organic wastewater containing ethylene oxide derivatives after the electro-catalytic oxidation treatment is adjusted to strong alkaline, and then filtration is performed, so that a filtrate is obtained, that is, the pretreatment of the organic wastewater containing ethylene oxide derivatives is completed.

[0012] The present application can effectively remove the COD and biological toxicity of the ethylene oxide wastewater and improve the biodegradability by cracking reduction and electro-catalytic oxidation treatment of the ethylene oxide wastewater.

[0013] The catalytic cracking is the result of the joint action of carbonium ion and free radical reaction mechanisms, but the specific cracking reaction mechanism is different with different catalysts and cracking processes. The chain or ring macromolecular organic matter in the wastewater is broken into small molecular organic matter which is easy to degrade by catalytic cracking.

[0014] The small molecular organic matter in the wastewater is oxidized and degraded by electro-catalytic oxidation treatment of the effluent after catalytic cracking reduction.

[0015] Further, in the step (a), the flocculation is performed by adding a coagulant and a coagulant aid under mechanical stirring, the coagulant is polymeric ferric chloride sulfate, the mass concentration of 10% polymeric ferric chloride sulfate is 1000 ppm, and the coagulant aid is sodium silicate, the mass concentration of 10% sodium silicate is 500 ppm.

[0016] Further, in the step (a), the pH is adjusted to 9-10, and the flocculation sedimentation time is 1-2 h.

[0017] Further, in the step (a), the flocculation condition is pH=10.

[0018] Further, in the step (c), the specific process of the electro-catalytic oxidation treatment is that the organic wastewater containing ethylene oxide derivatives after the catalytic cracking reduction treatment is sent into an electro-catalytic reactor to react, without additional pH adjustment, and the reaction time is 120-180 min.

[0019] Further, in the step (b), the reaction time is 180 min.

[0020] Further, in the step (c), the reaction time is 120 min.

[0021] Further, in the step (d), the wastewater is adjusted to strong alkaline, pH = 10-12.

[0022] Further, in the step (d), a plate and frame filter press is used for pressure filtration.

[0023] Further, in the step (b), the cracking reduction catalyst comprises a catalyst carrier, a pore former and an active component, the catalyst carrier component is carbon powder, iron powder and diatomite, the active component comprises yttrium nitrate and titanium dioxide, and the pore former is polyvinylpyrrolidone (PVP).

[0024] Further, the cracking reduction catalyst is composed of the following raw materials in mass percentage: 70-90% of the catalyst carrier, 5-10% of the pore former and 5-20% of the active component.

[0025] Further, the cracking reduction catalyst is composed of the following raw materials in mass percentage: 75% of the catalyst carrier, 10% of the pore former and 15% of the active component.

[0026] Further, in the catalyst carrier, the mass fraction of diatomite in the carrier component is 5-10%, the mass fraction of carbon powder in the carrier component is 15-30%, and the mass fraction of iron powder in the carrier component is 60-80%.

[0027] Further, in the catalyst carrier, the mass fraction of diatomite in the carrier component is 7%, the mass fraction of carbon powder in the carrier component is 15%, and the mass fraction of iron powder in the carrier component is 78%.

[0028] Further, in the active component, the mass fraction of yttrium nitrate in the active component is 70-90%, and the mass fraction of titanium dioxide in the active component is 10-30%.

[0029] Further, in the active component, the mass fraction of yttrium nitrate in the active component is 81%, and the mass fraction of titanium dioxide in the active component is 19%.

[0030] Further, the preparation steps of the cracking reduction catalyst are as follows:

[0031] S1, mix the catalyst carrier and the active component according to a certain proportion, add titanium tetrabutoxide, the addition amount of titanium tetrabutoxide is 12%, stir to form a uniform paste, then add the pore former and stir uniformly;

[0032] S2, the paste obtained in step S1 is compressed into agglomerates using a press, namely catalyst precursor agglomerates. The diameter of the catalyst precursor agglomerates is controlled within the range of 15~20mm, and a pore-expanding skeleton is inserted into the precursor agglomerates.

[0033] S3. The precursor group is placed in a muffle furnace and calcined at high temperature for 3 hours at a temperature of 900~1100℃. After calcination, it is cooled to room temperature and the expanded pore framework is extracted to obtain the cracking reduction catalyst.

[0034] Furthermore, the enlarged hole frame is a cylindrical rod made of stainless steel with a diameter of 3mm and a length of 10mm.

[0035] The electrocatalytic oxidation reactor includes an anode plate and a cathode plate connected to positive and negative electrodes respectively. An electrocatalyst is filled between the cathode plate and the anode plate. The anode plate is made of SnO2 / Cu, and the cathode plate is made of Ti. The optimal current for the electrocatalytic oxidation reaction is 0.1A, and the reaction time is 3-4h.

[0036] The ethylene oxide derivative-containing organic wastewater is a high-COD, high-surfactant ethylene oxide derivative (EOD) wastewater, with a COD content of 10,000-40,000 mg / L.

[0037] This invention discloses a pretreatment device for organic wastewater containing ethylene oxide derivatives, comprising a flocculation tank, a catalytic cracking and reduction reactor, an electrocatalytic oxidation reactor, an acid-base adjustment tank, and a plate and frame filter press connected in sequence.

[0038] The present invention has the following advantages over the prior art:

[0039] This invention proposes a combined catalytic cracking-reduction and electrocatalytic oxidation treatment technology. The catalyst used in the catalytic cracking-reduction is a self-made spherical solid. Catalytic cracking breaks down the chain-like and ring-like macromolecular organics within ethylene oxide derivative (EOD) wastewater into smaller organic molecules, which are then further degraded by electrocatalytic oxidation. As a wastewater pretreatment technology, this method demonstrates high treatment efficiency for ethylene oxide derivative (EOD) wastewater, and the treated organic wastewater meets the requirements for subsequent biochemical treatment.

[0040] This invention uses a combined catalytic cracking reduction and electrocatalytic oxidation treatment technology. The catalytic cracking reduction reaction has a pH of 3.5. After the catalytic cracking reduction treatment, the pH of the organic wastewater containing ethylene oxide derivatives rises to neutral. Therefore, no additional pH adjustment is required after the catalytic cracking reduction reaction, which reduces the operation process and lowers the cost.

[0041] The self-made cracking reduction catalyst with added active component yttrium has catalytic activity and weakens the interaction between the metal element and the support, which increases the dispersion of the metal element, lowers the reduction temperature of the metal element, and makes it easier to reduce. Detailed Implementation

[0042] To make the preparation steps of this invention clearer, and the effects and advantages of the product more apparent, the technical solution of this invention will be described in detail below. The embodiments described below are merely some embodiments of this invention, not all embodiments. These embodiments help to interpret and define the inventive content of this invention. Other implementation methods obtained by other researchers in this field without making significant creative efforts are all within the scope of protection of this invention.

[0043] Example 1: This example provides a pretreatment method for organic wastewater containing ethylene oxide derivatives, including the following steps:

[0044] (a) Flocculation pretreatment: Add the organic wastewater containing ethylene oxide derivatives into the flocculation tank for flocculation pretreatment to remove high molecular weight organic matter and particulate matter from the organic wastewater containing ethylene oxide derivatives.

[0045] (b) Catalytic cracking and reduction treatment: The organic wastewater containing ethylene oxide derivatives after flocculation pretreatment is sent to the catalytic cracking reactor to react with the cracking and reduction catalyst. The reaction pH is controlled at 3.5. The reaction does not require stirring and the reaction time is 180 min.

[0046] (c) Electrocatalytic oxidation treatment: The pH of the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment is raised to neutral, pH=7~9, and then an electrocatalytic oxidation reaction is carried out in an electrocatalytic oxidation reactor. Aeration is used as stirring, the reaction current is 0.1A, the hydrogen peroxide dosage is 1‰, and the reaction time is 180min.

[0047] (d) Filtration: Add lime to adjust the pH of the organic wastewater containing ethylene oxide derivatives after electrocatalytic oxidation to 12, and then filter it in a filter press to obtain the filtrate.

[0048] In this embodiment, in step (a), flocculation is carried out by adding a coagulant and a coagulant aid and mechanically stirring. The coagulant is polyferric chloride, and the dosage of 10% polyferric chloride is 1000 ppm. The coagulant aid is sodium silicate, and the dosage of 10% sodium silicate is 500 ppm.

[0049] In this embodiment, in step (a), the flocculation conditions are pH=10, the stirring time is 20 min, and the flocculation sedimentation time is 2 h.

[0050] In this embodiment, the preparation steps of the pyrolysis-reduction catalyst are as follows:

[0051] S1, the catalyst support and active components are mixed in a certain proportion, tetrabutyl titanate is added, the amount of tetrabutyl titanate added is 12%, and the mixture is stirred into a uniform paste. Then, the pore-forming agent is added and stirred evenly.

[0052] S2, the paste obtained in step S1 is compressed into agglomerates using a press, namely catalyst precursor agglomerates. The diameter of the catalyst precursor agglomerates is controlled within the range of 15~20mm, and a pore-expanding skeleton is inserted into the precursor agglomerates.

[0053] S3. The precursor group is placed in a muffle furnace and calcined at high temperature for 3 hours at a temperature of 900~1100℃. After calcination, it is cooled to room temperature and the expanded pore framework is extracted to obtain the cracking reduction catalyst.

[0054] Furthermore, the enlarged hole frame is a cylindrical rod made of stainless steel with a diameter of 3mm and a length of 10mm.

[0055] In this embodiment, in step (b), the cracking reduction catalyst includes a catalyst support, a pore-forming agent, and an active component. The cracking reduction catalyst is composed of the following raw materials by mass percentage: 75% catalyst support, 10% pore-forming agent, and 15% active component. In the catalyst support, diatomaceous earth accounts for 7% of the mass fraction of the support component, carbon powder accounts for 15% of the mass fraction of the support component, and iron powder accounts for 78% of the mass fraction of the support component. In the active component, yttrium nitrate accounts for 81% of the mass fraction of the active component, and titanium dioxide accounts for 19% of the mass fraction of the active component.

[0056] The performance of the pretreatment method for organic wastewater containing ethylene oxide derivatives in this embodiment was tested.

[0057] Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a chemical plant as an example, the wastewater has a high concentration of organic matter, a COD (chemical oxygen demand) of 18,000 mg / L, a high content of surfactants, many bubbles, and a complex composition. The environmental capacity of biochemical methods for COD is below 5,000 mg / L, and direct biochemical treatment cannot meet the national emission standards.

[0058] According to the pretreatment method for ethylene oxide derivative-containing organic wastewater described in the above technical solution, the treated wastewater was tested. The chemical oxygen demand (COD) monitoring data of the wastewater at each stage of the above treatment process are as follows: COD of raw water was 18600 mg / L; COD of wastewater after flocculation pretreatment was 15970 mg / L; COD of wastewater after catalytic cracking and reduction treatment was 7980 mg / L; and COD of wastewater after electrocatalytic oxidation treatment was 4750 mg / L. This method can reduce the organic matter in wastewater to an acceptable range for biochemical treatment, allowing for further biochemical treatment to meet national discharge standards.

[0059] Comparative Example 1: Taking the aforementioned example of the actual application of organic wastewater containing ethylene oxide derivatives from a chemical plant, the wastewater has a high concentration of organic matter, a COD (chemical oxygen demand) of 18432 mg / L, high surfactant content, numerous bubbles, and a complex composition. After direct biological treatment, the effluent COD is 16387 mg / L, far below the national discharge standard. Furthermore, due to the excessively high COD content of the raw water, exceeding the maximum limit that microorganisms can treat, a large number of microorganisms die, resulting in a decrease in the treatment efficiency of the subsequent biological reaction tank.

[0060] Comparative Example 2: Taking the actual application of organic wastewater containing ethylene oxide derivatives from a certain chemical plant as an example, the wastewater has a high concentration of organic matter and a COD (chemical oxygen demand) of 18582 mg / L. Pretreatment using the iron-carbon micro-electrolysis-Fenton combined oxidation method resulted in a COD of 9785 mg / L after pretreatment. The treatment effect was lower than that of catalytic cracking-electrocatalysis, and it could not reduce the organic matter in the wastewater to an acceptable range for biochemical treatment. Even after pretreatment using the iron-carbon micro-electrolysis-Fenton combined oxidation method, biochemical treatment still could not meet the national emission standards.

[0061] Example 2 provides a pretreatment method for organic wastewater containing ethylene oxide derivatives, including the following steps:

[0062] (a) Flocculation pretreatment: Add the organic wastewater containing ethylene oxide derivatives into the flocculation tank for flocculation pretreatment to remove high molecular weight organic matter and particulate matter from the organic wastewater containing ethylene oxide derivatives.

[0063] (b) Catalytic cracking and reduction treatment: The organic wastewater containing ethylene oxide derivatives after flocculation pretreatment is sent to the catalytic cracking reactor to react with the cracking and reduction catalyst. The reaction pH is controlled at 3.5. The reaction does not require stirring and the reaction time is 180 min.

[0064] (c) Electrocatalytic oxidation treatment: The pH of the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment is raised to neutral, and then an electrocatalytic oxidation reaction is carried out in an electrocatalytic oxidation reactor. Aeration is used as stirring, the reaction current is 0.1A, the hydrogen peroxide dosage is 1‰, and the reaction time is 180min.

[0065] (d) Filtration: Add lime to adjust the pH of the organic wastewater containing ethylene oxide derivatives after electrocatalytic oxidation to 12, and then filter it in a filter press to obtain the filtrate.

[0066] Other conditions are the same as in Example 1.

[0067] Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a chemical plant as an example, the wastewater has a high concentration of organic matter, a COD (chemical oxygen demand) of 18,000 mg / L, a high content of surfactants, many bubbles, and a complex composition. Direct biochemical treatment cannot meet the national emission standards.

[0068] According to the pretreatment method for organic wastewater containing ethylene oxide derivatives described in the above technical solution, the chemical oxygen demand (COD) of the treated wastewater is tested.

[0069] Comparative Example 1: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, the pH of the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment in step (c) of Example 2 was adjusted to 2-4, while other conditions remained unchanged, and the chemical oxygen demand of the treated wastewater was tested.

[0070] Comparative Example 2: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, the pH of the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment in step (c) of Example 2 was adjusted to 12-13, while other conditions remained unchanged, and the chemical oxygen demand of the treated wastewater was tested.

[0071] The chemical oxygen demand (COD) data for Example 2 and Comparative Examples 1 and 2 are as follows:

[0072]

[0073] As shown in the table, the electrochemical effect is the best under neutral conditions, and the COD of the effluent meets the requirement of 5000 mg / L for the biological treatment tank.

[0074] Comparative Example 3: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, hydrogen peroxide was not added in step (c) of Example 2, and other conditions remained unchanged. The chemical oxygen demand of the treated wastewater was tested.

[0075] The chemical oxygen demand (COD) data for Example 2 and Comparative Example 3 are as follows:

[0076]

[0077] As shown in the table, without the addition of hydrogen peroxide, the electrochemical effect deteriorates, but the difference is not significant. However, the COD of the effluent cannot meet the requirement of 5000 mg / L for the biological treatment tank.

[0078] Comparative Example 4: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, the reaction current in step (c) of Example 2 was 0.05A, and other conditions remained unchanged. The chemical oxygen demand of the treated wastewater was tested.

[0079] Comparative Example 5: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, the reaction current in step (c) of Example 2 was 0.2A, and other conditions remained unchanged. The chemical oxygen demand of the treated wastewater was tested.

[0080] Comparative Example 6: Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a certain chemical plant as an example, the reaction current in step (c) of Example 2 was 0.3A, and other conditions remained unchanged. The chemical oxygen demand of the treated wastewater was tested.

[0081] The chemical oxygen demand (COD) data for Example 2 and Comparative Examples 4, 5, and 6 are as follows:

[0082]

[0083] As shown in the table, the electrochemical effect is better as the electrochemical reaction current increases. When the reaction current reaches and exceeds 0.1A, the COD of the effluent meets the requirement of 5000mg / L for the biological treatment tank.

[0084] Example 3: In this example, the pretreatment method for organic wastewater containing ethylene oxide derivatives includes the same steps as in Example 1.

[0085] In this embodiment, in step (b), the cracking reduction catalyst includes a catalyst support, a pore-forming agent, and an active component. The cracking reduction catalyst is composed of the following raw materials by mass percentage: 75% catalyst support, 10% pore-forming agent, and 15% active component. In the catalyst support, diatomaceous earth accounts for 7% of the mass fraction of the support component, carbon powder accounts for 15% of the mass fraction of the support component, and iron powder accounts for 78% of the mass fraction of the support component. In the active component, yttrium nitrate accounts for 81% of the mass fraction of the active component, and titanium dioxide accounts for 19% of the mass fraction of the active component.

[0086] The performance of the pretreatment method for organic wastewater containing ethylene oxide derivatives in this embodiment was tested.

[0087] Taking the actual application of organic wastewater containing ethylene oxide derivatives generated by a chemical plant as an example, the wastewater has a high concentration of organic matter, a COD (chemical oxygen demand) of 18,000 mg / L, a high content of surfactants, many bubbles, and a complex composition. Direct biochemical treatment cannot meet the national emission standards.

[0088] According to the pretreatment method for organic wastewater containing ethylene oxide derivatives described in Example 1, the treated wastewater was pretreated, and the chemical oxygen demand (COD) of the treated wastewater was tested.

[0089] Comparative Example 1: Taking the actual application of organic wastewater containing ethylene oxide derivatives from a chemical plant as an example, a series of experiments were conducted with different mass ratios of catalyst support, pore-forming agent, and active component as in Example 3, while keeping other conditions constant. The chemical oxygen demand (COD) of the treated wastewater was then tested. Representative results are shown in the table below:

[0090]

[0091] As shown in the table, the maximum proportions of catalyst support, porogen, and active component were determined. Based on the experimental phenomena and previous data, a comprehensive comparison showed that when the mass ratio of catalyst support: porogen: active component was 75:10:15, the catalyst performance was the best, and the effluent COD met the requirement of 5000 mg / L for the biological treatment tank.

[0092] Comparative Example 2: Again, taking the actual application of organic wastewater containing ethylene oxide derivatives from a chemical plant as an example, a series of experiments were conducted with different mass ratios of the catalyst support components from Example 3, while keeping other conditions constant. The chemical oxygen demand (COD) of the treated wastewater was then tested. Representative results are shown in the table below:

[0093]

[0094] As shown in the table, the maximum proportions of diatomaceous earth, carbon powder, and iron powder in the catalyst carrier were determined. Based on the experimental phenomena and previous data, the comprehensive comparison results show that when the mass ratio of diatomaceous earth:carbon powder:iron powder is 7:15:78, the catalyst performance is the best, and the effluent COD meets the requirement of 5000 mg / L for the biological treatment tank.

[0095] Comparative Example 3: Again, taking the actual application of organic wastewater containing ethylene oxide derivatives from a chemical plant as an example, a series of different ratio experiments were conducted using different mass ratios of the catalyst active components from Example 3, with other conditions remaining unchanged. The chemical oxygen demand (COD) of the treated wastewater was then tested. Representative ratio results are shown in the table below:

[0096]

[0097] As shown in the table, the maximum ratio of yttrium nitrate and titanium dioxide, the active components of the catalyst, were determined. Based on the experimental phenomena and previous data, the comprehensive comparison results show that when the mass ratio of yttrium nitrate to titanium dioxide is 81:19, the catalyst performance is the best, and the COD of the effluent meets the requirement of 5000 mg / L for the biological treatment tank.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions 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, and they should all be covered within the scope of the claims and specification of the present invention. For those skilled in the art, any alternative improvements or transformations made to the embodiments of the present invention fall within the protection scope of the present invention.

[0099] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A pretreatment method for organic wastewater containing ethylene oxide derivatives, characterized in that, Includes the following steps, (a) Flocculation pretreatment: Add the organic wastewater containing ethylene oxide derivatives into the flocculation tank, adjust the pH, and carry out flocculation pretreatment to remove high molecular weight organic matter and particulate matter from the organic wastewater containing ethylene oxide derivatives. (b) Catalytic cracking and reduction treatment: The organic wastewater containing ethylene oxide derivatives after flocculation pretreatment is sent to the catalytic cracking reactor to react with the cracking and reduction catalyst. The pH of the reaction is controlled at 3.

5. The reaction does not require stirring and the reaction time is 120~240 min. (c) Electrocatalytic oxidation treatment: The pH of the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment is raised to neutral, and then an electrocatalytic oxidation reaction is carried out in an electrocatalytic oxidation reactor; (d) Filtration: Adjust the pH of the organic wastewater containing ethylene oxide derivatives after electrocatalytic oxidation to alkaline, then filter to obtain filtrate, thus completing the pretreatment of the organic wastewater containing ethylene oxide derivatives. The preparation steps of the pyrolysis-reduction catalyst are as follows: S1, mix the catalyst support and active components in a certain proportion, add tetrabutyl titanate, stir until uniform to a paste, then add the pore-forming agent and stir until uniform; S2, the paste obtained in step S1 is compressed into agglomerates using a press, namely catalyst precursor agglomerates. The diameter of the catalyst precursor agglomerates is controlled within the range of 15~20mm, and a pore-expanding skeleton is inserted into the precursor agglomerates. S3, the precursor group is placed in a muffle furnace and calcined at high temperature for 3 hours at a temperature of 900~1100℃. After calcination, it is cooled to room temperature and the expanded pore framework is extracted to obtain the cracking reduction catalyst. The cracking and reduction catalyst is composed of the following raw materials by mass percentage: 70%~90% catalyst support, 5%~10% pore-forming agent, and 5%~20% active component; In step (a), flocculation is carried out by adding a coagulant and a coagulant aid and mechanically stirring. The coagulant is polyferric chloride and the coagulant aid is sodium silicate. In step (a), the pH is adjusted to 9-10 and the flocculation and settling time is 1-2 hours. In step (c), the specific process of the electrocatalytic oxidation treatment is as follows: the organic wastewater containing ethylene oxide derivatives after catalytic cracking and reduction treatment is sent to the electrocatalytic reactor for reaction without additional pH adjustment, and the reaction time is 180 minutes. In step (d), the wastewater is adjusted to strong alkalinity, pH=10-12.

2. The pretreatment method for organic wastewater containing ethylene oxide derivatives according to claim 1, characterized in that, In step (b), the cracking reduction catalyst includes a catalyst support, a pore-forming agent, and an active component. The catalyst support consists of carbon powder, iron powder, and diatomaceous earth. The active component includes yttrium nitrate and titanium dioxide. The pore-forming agent is polyvinylpyrrolidone (PVP).

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