Anode material for treating organic wastewater and preparation method and application thereof

Abstract

The application discloses a preparation method of an anode material for treating organic wastewater, and comprises the following steps: (1) dissolving silver nitrate, ammonia water, sodium hydroxide and formaldehyde in deionized water to obtain a precursor solution, then fixing a commercial electrode in the precursor solution, and performing heating and stirring treatment to obtain an Ag / commercial electrode sheet; (2) preparing a plating solution by using nickel salt, ethylenediamine, potassium borohydride and sodium hydroxide, then fixing the Ag / commercial electrode sheet obtained in the step (1) in the plating solution, and performing heating and stirring treatment, and then performing washing and drying to obtain the anode material. When the electrode material is used for electrocatalytic oxidation treatment of 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine wastewater, the ammonia oxidation rate is higher, and the COD and NH4-N values of the organic wastewater can be effectively reduced. The application further discloses the anode material obtained by the preparation method and application thereof.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic wastewater treatment, and particularly relates to an anode material for treating organic wastewater from preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine and a preparation method and application thereof. BACKGROUND

[0002] 3-aminomethyl-3,5,5-trimethylcyclohexylamine is an important amine compound, which is mainly used as a curing agent for epoxy resin, a crosslinking agent and a coupling agent for polyurethane, and an amine component for polyamide, and has a broad application prospect in industrial production process. In the production process of 3-aminomethyl-3,5,5-trimethylcyclohexylamine, industrial wastewater containing a small amount of 1,3,3-trimethyl-bicyclo[3,2,1]-6-azepane, 3-aminomethyl-3,5,5-trimethylcyclohexylamine and other organic matters is generated. However, due to the special molecular structure of 3-aminomethyl-3,5,5-trimethylcyclohexylamine, the commonly used wastewater treatment method of activated sludge method is difficult to effectively degrade and remove it and similar organic matters. Therefore, developing a safe and effective treatment method for such wastewater has become an important research topic.

[0003] CN105645555A provides a method for treating contaminated wastewater from the preparation process of 3,5,5-trimethyl-2-cyclohexen-1-one, 1,5,5-trimethyl-3-carbonyl-cyclohexanitrile and 3-aminomethyl-3,5,5-trimethylcyclohexylamine, which realizes efficient treatment of 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater by combining wet oxidation method with activated sludge method. The specific implementation process is as follows: the organic wastewater generated in the three-step production process of 3-aminomethyl-3,5,5-trimethylcyclohexylamine is added with an oxidizing agent (sodium hypochlorite) for wet oxidation, and sulfuric acid is used for pH neutralization, and then the treated wastewater is sent to biochemical treatment, and the CBS degradation rate can be increased from 36% to 46%.

[0004] CN113880195B mentions a preparation method of an anode material for treating organic wastewater containing ammonia nitrogen or amino groups, which adopts a reverse-phase suspension polymerization method to synthesize a material template, a thermal decomposition method to prepare a composite microsphere structure, and a cathodic electrodeposition method to prepare an anode material, finally a Ti / P(AM-Co-MAA)-Ru-Sn / PbO2 composite modified electrode is prepared by a template method, and the electrode is applied to treat wastewater containing p-acetamidophenol, realizing a good COD degradation rate.

[0005] At present, the main shortcomings of the prior art are as follows:

[0006] (1) In industrial production, activated sludge method is commonly used as a wastewater treatment method, but it cannot achieve good treatment effect for wastewater containing 3-aminomethyl-3,5,5-trimethylcyclohexylamine and by-products thereof;

[0007] (2) Before using activated sludge method to treat wastewater containing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, wet oxidation pretreatment is needed, which requires a heat source to maintain a certain treatment temperature, and an oxidizing agent is used to oxidize the wastewater in the process, and sulfuric acid and sodium sulfite are used for pH adjustment and tail-end treatment after oxidation, so the treatment process is relatively complicated;

[0008] (3) The degradation of organic pollutants in the BDD electrode system is mainly based on the oxidation mechanism of directly or indirectly generating hydroxyl radicals on the electrode surface, therefore, the electro-catalytic oxidation process is limited by the low conversion efficiency of ammonia nitrogen to nitrogen, which cannot achieve the purpose of denitrification, resulting in that the total nitrogen content and organic matter in the water cannot be effectively removed.

[0009] In summary, the activated sludge method cannot achieve good wastewater treatment effect for wastewater containing 3-aminomethyl-3,5,5-trimethylcyclohexylamine and by-products thereof, and the treatment process is relatively complicated when using wet oxidation pretreatment before biochemical treatment; at present, the BDD electrode used in electro-catalytic method has not achieved good removal effect for total nitrogen and organic pollutants in water. SUMMARY

[0010] The present application first provides a preparation method of an anode material for treating organic wastewater, which has a higher ammonia oxidation rate when used for electro-catalytic oxidation treatment of 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater, and can effectively reduce the COD and NH4-N values of organic wastewater. The present application also provides the anode material obtained by the preparation method and its application.

[0011] A preparation method of an anode material for treating organic wastewater, comprising the following steps:

[0012] (1) Dissolving silver nitrate, ammonia water, inorganic base and formaldehyde in deionized water to obtain a precursor solution, then fixing a commercial electrode in the precursor solution, and heating and stirring to obtain an Ag / commercial electrode sheet;

[0013] (2) Preparing a plating solution by using nickel salt, ethylenediamine, borohydride salt and inorganic base, then fixing the Ag / commercial electrode sheet obtained in step (1) in the plating solution, heating and stirring to treat, and then washing and drying to obtain the anode material;

[0014] The inorganic base is sodium hydroxide, potassium hydroxide or lithium hydroxide, wherein the inorganic bases in steps (1) and (2) can be the same or different;

[0015] The borohydride salt is sodium borohydride or potassium borohydride.

[0016] The application uses a chemical plating method to load amorphous Ni-B on a commercial BDD electrode for electrode modification. The chemical plating method can realize directional deposition of metal and high dispersibility of modified substances, thereby significantly improving the electrochemical performance of the electrode material. Based on the good ammonia oxidation effect of the BDD electrode, the B element in the Ni-B crystal accelerates the electron interaction between the modified substances and the electrode, thereby greatly improving the ammonia oxidation rate of the electrode system. The prepared Ni-B loaded BDD electrode is used for electrocatalytic oxidation treatment of 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine wastewater, and then the pretreated wastewater is sent to a biochemical tank for biochemical treatment, thereby improving the wastewater treatment effect. Compared with the single activated sludge method, the COD degradation rate of the wastewater pretreated by electrocatalytic oxidation can be increased from 9.8% to 96.8%.

[0017] As preferred, in step (1), the molar ratio of silver nitrate, ammonia water, inorganic base, and formaldehyde is 1:30-40:1.0-1.2:0.2-0.8; further preferably 1:36:1:0.6.

[0018] As preferred, in step (1), the commercial electrode is a commercial BDD electrode, a C electrode, or a PbO2 electrode, further preferably a BDD electrode, which can more effectively improve the treatment efficiency compared with other electrodes.

[0019] As preferred, in step (1), the temperature of heating and stirring is 30-130°C, further preferably 30-40°C, and more further preferably 40°C. The time of heating and stirring is 2-6h, further preferably 2-4h, and more further preferably 4h.

[0020] As preferred, in step (1), after heating and stirring, the residual powder in the solution is taken out, filtered, and washed, and then is transferred into the plating solution of step (2) together with the Ag / commercial electrode sheet.

[0021] In step (2), the molar ratio of the nickel salt, ethylenediamine, borohydride salt, and inorganic base is 1:5-15:2-6:35-40; further preferably 1:10:4:37.

[0022] As preferred, in step (2), the nickel salt is nickel nitrate, nickel sulfate, nickel chloride, or a hydrate thereof, further preferably nickel sulfate or a hydrate thereof.

[0023] As preferred, in step (2), the temperature of the heating and stirring is 30-130℃, and the time of the heating and stirring is 20-100min. As further preferred, the temperature of the heating and stirring is 30-45℃, and the time of the heating and stirring is 20-35min; as still further preferred, the temperature of the heating and stirring is 45℃, and the time of the heating and stirring is 35min.

[0024] As preferred, in step (2), the washing is sequentially performed with deionized water and anhydrous alcohol, and then the washing is naturally dried.

[0025] The present application also provides an anode material prepared by the above method.

[0026] The present application also provides a method for treating 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater, comprising the following steps:

[0027] (A) using the above anode material as an anode and using an uncorroded steel mesh as a cathode, performing electrocatalytic oxidation treatment on the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater by electrifying to obtain pretreated wastewater;

[0028] (B) transferring the pretreated wastewater to a biological wastewater purification environment to perform static biological degradation to obtain treated wastewater.

[0029] In step (A), the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is wastewater generated in the production process of 3-aminomethyl-3,5,5-trimethylcyclohexylamine, and there is no particularly strict requirement, as long as it contains 3-aminomethyl-3,5,5-trimethylcyclohexylamine or similar substances (for example, 1,3,3-trimethyl-bicyclo[3,2,1]-6-azacycloheptane) as pollutants. As preferred, the COD of the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is 2500-3500mg / L, and the NH3-N is 100-200mg / L, and the method of the present application can be better for treatment.

[0030] As preferred, in step (A), the current density is 30-60mA·cm -2 , and the treatment time is 4-10h; as further preferred, the current density is 45mA·cm -2 , and the treatment time is 6h.

[0031] In step (B), the static biological degradation method is a prior art, and can be an aerobic sludge degradation method.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The application uses a chemical plating method to load amorphous Ni-B on a commercial BDD electrode for electrode modification, greatly improves the ammonia oxidation rate of the electrode system, and uses the prepared Ni-B loaded BDD electrode for electrocatalytic oxidation treatment of 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine wastewater, and then the pretreated wastewater is sent to a biochemical tank for biochemical treatment, which can effectively improve the wastewater treatment effect. DETAILED DESCRIPTION

[0034] In the application, the COD determination method in wastewater is as follows:

[0035] Sample preparation: 0.5g of sample is diluted with water to 50g to obtain a test solution. 2.5mL of distilled water (as a blank solution) and the test solution are respectively taken into two digestion tubes, and 0.7mL of LH-YD-100 reagent and 4.8mL of LH-YE-100 reagent are respectively added to each digestion tube. Tighten the digestion tube cover and shake well. Open the digestion tube cover, place the digestion tube vertically in the intelligent digestion instrument, and digest at 165℃ for 10min. After digestion, the digestion tube is taken out vertically and placed in air to cool for 2min, and then 2.5mL of distilled water is added to each digestion tube, shaken well and then placed in cold water to cool for 2min.

[0036] Determination: According to the operation rules of the DR6000 ultraviolet spectrophotometer, the prepared COD standard curve is called out, and the blank solution is used to deduct the blank at 610nm wavelength, and then the absorbance of the above treated test solution is tested. The instrument automatically displays the COD value of the test sample.

[0037] Data processing: According to the COD value of the diluted test sample read on the DR6000 ultraviolet spectrophotometer, the COD value of the test sample can be calculated according to formula (1):

[0038]

[0039] In the formula:

[0040] COD 供试品 The COD value of the test sample is in milligrams per liter (mg / L);

[0041] COD 仪器读数 The COD value of the diluted test sample read on the ultraviolet spectrophotometer is in milligrams per liter (mg / L);

[0042] m2-the total mass of the diluted test sample solution, in grams (g);

[0043] m1-the mass of the test sample, in grams (g).

[0044] Examples 1-3

[0045] 2 -2

[0046] Table 2.1 Influence of different basic electrodes on COD and ammonia nitrogen degradation efficiency of wastewater

[0047]

[0048] Examples 4-5

[0049] ​​​The commercial BDD electrode is used as a basic electrode, which is placed in the Ag / commercial electrode precursor solution, and the precursor solution is composed of silver nitrate 0.04 g, ammonia water 0.3 g, sodium hydroxide 0.01 g, formaldehyde 0.004 g, and deionized water 950 mL, to prepare the Ag / BDD electrode. Then, the nickel sulfate, nickel nitrate solution, and nickel chloride are used as the plating solution nickel source, respectively, and the electroplating solution is composed of nickel nitrate (hexahydrate) 7.85 g or nickel sulfate (hexahydrate) 7.1 g or nickel chloride (hexahydrate) 6.42 g, ethylenediamine 16.6 g, potassium borohydride 5.5 g, and sodium hydroxide 40.0 g, to prepare the Ni-B / BDD electrode. The simulated 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is configured, 3-aminomethyl-3,5,5-trimethylcyclohexylamine is used as the target pollutant, and the treatment solution with a concentration of 1000 mg / L is configured, and the COD is measured to be 3115 mg / L, and the NH3-N is measured to be 121.2 mg / L. Then, 1000 mL of the treatment solution is taken, the external chloride ion concentration is 0.05 mol / L, and the pH value is adjusted to 3. The Ni-B / BDD electrode prepared in the example is used as the anode, and the stainless steel mesh electrode with the same size and volume is used as the cathode, a constant current mode is adopted, an electrocatalytic oxidation reaction system is constructed, and the simulated 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater treatment solution is treated, wherein the effective electrode area of the electrode is 6.25 cm 2 , and the current density is 45 mA·cm -2 . After 6 h of treatment, the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater pretreated by electrocatalytic oxidation is transferred to the static biodegradation experiment of the simulated biological wastewater purification device, the specific treatment conditions are the same as those in example 1, the COD and NH3-N contents in the wastewater are measured, and the effects of different electrodes on the COD and ammonia nitrogen degradation efficiency of the treatment solution are shown in Table 2.2.

[0050] Table 2.2 Effects of different nickel sources on COD and ammonia nitrogen degradation efficiency of wastewater

[0051]

[0052]

[0053] Comparative Example 1

[0054] The simulated 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is configured, 3-aminomethyl-3,5,5-trimethylcyclohexylamine is taken as a target pollutant, a treatment liquid with a concentration of 1000 mg / L is configured, COD is measured as 3115 mg / L, and NH3-N is measured as 121.2 mg / L; then, 1000 mL of the treatment liquid is taken, an external chloride ion concentration is 0.05 mol / L, and the pH value is adjusted to 3; a commercial BDD electrode is taken as an anode, a stainless steel mesh electrode with the same size and volume is taken as a cathode, a constant current mode is adopted, an electrocatalytic oxidation reaction system is constructed, and the simulated 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater treatment liquid is treated, wherein the effective electrode area of the electrode is 6.25 cm 2 , and the current density is 45 mA·cm -2 . After 6 hours of treatment, the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater pretreated by electrocatalytic oxidation is transferred to a static biological degradation experiment of the simulated biological wastewater purification device, the specific treatment conditions are the same as those in Example 1, the COD and NH3-N contents in the wastewater are measured, the COD and ammonia nitrogen degradation efficiency of the treatment liquid are shown in Table 2.3; Comparative Example 2

[0055] The simulated 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is configured, 3-aminomethyl-3,5,5-trimethylcyclohexylamine is taken as a target pollutant, a treatment liquid with a concentration of 1000 mg / L is configured, COD is measured as 3115 mg / L, and NH3-N is measured as 121.2 mg / L; the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater configured is directly transferred to a static biological degradation experiment of the simulated biological wastewater purification device, and biochemical treatment is performed, the specific treatment conditions are the same as those in Example 1, the COD and NH3-N contents in the wastewater are measured, and the COD and ammonia nitrogen degradation efficiency of the wastewater are shown in Table 2.3.

[0056] Table 2.3 COD and ammonia nitrogen degradation efficiency of wastewater in Comparative Examples 1 and 2

[0057] Electrode COD degradation rate % [percent NH3-N degradation] Comparative Example 1 35.3％ 32.3％ Comparative Example 2 9.8％ 2.7％

[0058] The commercial BDD electrode is modified by using a chemical plating method, based on the good ammonia oxidation effect of the BDD electrode, the B element in the high-dispersity Ni-B crystal accelerates the electron interaction between the modified substance and the electrode, and the ammonia oxidation rate of the electrode system is greatly improved. The prepared Ni-B loaded BDD electrode is used for electrocatalytic oxidation treatment of 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater which is difficult to be degraded by the activated sludge method, and then the pretreated wastewater is sent to a biochemical tank for biochemical treatment. Compared with the single activated sludge method treatment, the optimal COD degradation rate in the wastewater can be increased from 9.8% to 96.8%, and the optimal NH3-N (ammonium-nitrogen) content can be reduced from 121.2 mg / L to 8.6 mg / L.

Claims

1. A method for preparing an anode material for treating organic wastewater, characterized in that, Includes the following steps: (1) Dissolve silver nitrate, ammonia, inorganic base and formaldehyde in deionized water to obtain a precursor solution. Then fix the commercial electrode in the precursor solution and heat and stir to obtain Ag / commercial electrode sheet. (2) Prepare a plating solution by mixing nickel salt, ethylenediamine, borohydride salt and inorganic alkali, then fix the Ag / commercial electrode sheet obtained in step (1) in the plating solution, heat and stir for treatment, and obtain the anode material by washing and drying. The inorganic base is sodium hydroxide, potassium hydroxide, or lithium hydroxide; The borohydride salt is sodium borohydride or potassium borohydride; In step (1), the molar ratio of silver nitrate, ammonia, inorganic alkali, and formaldehyde is 1:30~40:1.0~1.2:0.2~0.8; In step (1), the commercial electrode is a commercial BDD electrode; In step (1), the heating and stirring temperature is 30℃~130℃, and the heating and stirring time is 2~6h; In step (1), after heating and stirring are finished, the powder remaining in the solution is removed, filtered, washed, and then transferred together with the Ag / commercial electrode sheet into the plating solution in step (2).

2. The method for preparing the anode material according to claim 1, characterized in that, In step (2), the nickel salt is nickel nitrate, nickel sulfate, nickel chloride, or their respective hydrates.

3. The method for preparing the anode material according to claim 1, characterized in that, In step (2), the heating and stirring temperature is 30~130℃, and the heating and stirring time is 20~100min.

4. An anode material obtained by the preparation method according to any one of claims 1 to 3.

5. A method for treating 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater, characterized in that, Includes the following steps: (A) Using the anode material described in claim 4 as the anode and a stainless steel mesh as the cathode, the 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater is subjected to electrocatalytic oxidation treatment by passing electricity to obtain pretreated wastewater; (B) The pretreated wastewater is transferred to a biological wastewater purification environment for static biodegradation to obtain treated wastewater.

6. The method for treating 3-aminomethyl-3,5,5-trimethylcyclohexylamine wastewater according to claim 5, characterized in that, In step (A), the current density is 30~60 mA·cm. -2 The processing time is 4 to 10 hours.

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