Treatment method of vinylene carbonate production waste

Abstract

The invention discloses a vinylene carbonate production waste treatment method, which comprises: dispersing triethylamine hydrochloride waste residue in water, filtering, adding excess alkali into the filtrate to carry out an alkaline hydrolysis reaction, and standing for layering to obtain an oil phase and a water phase, the oil phase containing triethylamine; adding calcium peroxide into the water phase, mixing and stirring to obtain a pretreatment solution; performing electrochemical catalytic oxidation treatment on the pretreatment solution, wherein a graphite felt electrode modified by a specific iron-based activated carbon catalyst is used as a cathode in the electrochemical catalytic oxidation treatment; the method is simple to operate, easy to implement, high in continuity, low in cost, free of high-temperature and high-pressure processes and excellent in treatment effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vinylene carbonate preparation and its post-processing, and particularly relates to a treatment method of vinylene carbonate production waste. BACKGROUND

[0002] Vinylene carbonate (VC) is an important chemical raw material, and its application fields are quite extensive, covering surface coating, pharmaceutical manufacturing, functional polymer materials, lithium ion batteries and many other aspects. Especially in the field of lithium battery electrolyte additives, vinylene carbonate plays an indispensable key role. Currently, the industrial production of vinylene carbonate is based on dimethyl carbonate or methyl tert-butyl ether as the solvent, and triethylamine reacts with chloroethylene carbonate to produce vinylene carbonate. Waste salt is generated during the reaction. The waste salt contains triethylamine hydrochloride, vinylene carbonate and polymers, and the colority of the waste salt is high. At present, most production enterprises choose to entrust professional institutions to process the waste salt, which undoubtedly increases the production cost. With the decline of the price of vinylene carbonate, in order to reduce the cost, the enterprises gradually change the outsourcing of triethylamine recovery to self-recovery and processing. However, during the self-processing, high-salt and high-organic wastewater containing sodium chloride is generated. If the wastewater is directly discharged without treatment, not only the sewage treatment fee and the pollution discharge fee will be increased, but also the environment will be polluted.

[0003] In the industrial field, the most commonly used method to treat such high-salt and high-organic wastewater is direct distillation. The generated sodium chloride can be crystallized into industrial salt through direct distillation of high-concentration wastewater. However, this method has obvious disadvantages. On the one hand, the energy consumption is relatively high; on the other hand, since the wastewater may contain up to 10wt.% of organic matter, the COD (chemical oxygen demand, which is a very important index for judging whether the water environment is polluted) is high, which makes the evaporation rate extremely slow. Moreover, a large amount of foam is generated during the evaporation process, which causes damage to the equipment.

[0004] In view of the above problems, some processes have been partially improved. For example, Chinese invention patent CN105923829A discloses a resource treatment method of triethylamine hydrochloride wastewater, which adopts alkali separation + wet oxidation + post-processing process to treat triethylamine hydrochloride aqueous solution, and recovers triethylamine in the triethylamine hydrochloride wastewater. Although this patent can remove the colority and organic matter of the wastewater and recover triethylamine, the control requirement of the alkali amount in the pretreatment stage is high, and if the pH value is too high, the pipeline may be blocked during wet oxidation, and if the pH value is too low, the triethylamine cannot be fully separated from the triethylamine hydrochloride, which may cause the triethylamine to reach the explosion limit under the subsequent high-temperature and high-pressure conditions, and cause danger. At the same time, the investment cost of the wet oxidation device is high, and the reaction conditions are harsh, which requires operation under high temperature and high pressure, and the energy consumption is large.

[0005] Patent CN118639248A discloses a method for recycling waste salt in the production of vinylene carbonate. The patent recovers triethylamine through a distillation process, then performs LBC chemical oxidation pretreatment on high-salt wastewater, and then evaporates and crystallizes to obtain industrial salt. The obtained crystalline salt is refined and configured into brine, which is treated by ozone / hydrogen peroxide (O3 / H2O2) synergistic oxidation, and the effluent is introduced into the ion membrane caustic soda system. The resulting sodium hydroxide solution and chlorine gas are sold as industrial products. This method realizes efficient recovery and recycling of waste salt through multi-stage treatment, but the wastewater treatment load is high and the steps are complex, the equipment investment cost is high, and it is difficult to operate stably in actual operation of the factory.

[0006] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore the background section of the present application can contain background information about the problems or environment of the present application, which is not necessarily a description of the prior art. Therefore, the content contained in the background section is not an admission by the applicant of prior art. SUMMARY

[0007] The purpose of the present application is to overcome one or more of the deficiencies in the prior art, and to provide a new method for treating waste from the production of vinylene carbonate. The method is simple to implement, does not require high temperature and high pressure during the treatment process, is safe, and has good treatment effect.

[0008] To achieve the above-mentioned purpose, a technical solution adopted by the present application is:

[0009] A method for treating waste from the production of vinylene carbonate, the waste from the production of vinylene carbonate comprising triethylamine hydrochloride waste residue, the post-treatment method comprising:

[0010] Dispersing the triethylamine hydrochloride waste residue in water, filtering, adding excess base to the filtrate for alkaline hydrolysis, and standing to separate into an oil phase and an aqueous phase, the oil phase comprising triethylamine;

[0011] Adding calcium peroxide to the aqueous phase, mixing and stirring to obtain a pretreated solution;

[0012] Performing electrochemical catalytic oxidation treatment on the pretreated solution, the electrochemical catalytic oxidation treatment using a modified graphite felt electrode as a cathode;

[0013] Wherein, the amount of calcium peroxide added is more than 10% of the mass of the aqueous phase;

[0014] The modified graphite felt electrode is prepared by the following method: acidizing treatment of activated carbon, washing and drying, first calcination treatment under a protective atmosphere to obtain pretreated activated carbon; mixing the pretreated activated carbon, divalent iron ions and / or trivalent iron ions, drying and then second calcination treatment under a protective atmosphere to obtain a catalyst, mixing the catalyst, a binder and a conductive agent and then applying the mixture on a graphite felt to prepare the modified graphite felt electrode.

[0015] According to the present application, the triethylamine hydrochloride waste residue comprises triethylamine hydrochloride and organic matter, the organic matter comprises vinylene carbonate and polymer, wherein the mass content of the organic matter in the triethylamine hydrochloride waste residue is 5% or more, further 5%-15%.

[0016] In some embodiments of the present application, the mass ratio of the triethylamine hydrochloride waste residue to the water is 1:2-5. Further, the mass ratio of the triethylamine hydrochloride waste residue to the water is 1:2-3.

[0017] In some embodiments of the present application, the water used for dispersing the triethylamine hydrochloride waste residue can be directly tap water.

[0018] In some embodiments of the present application, the triethylamine hydrochloride waste residue is dispersed in water, filtered, and the filtered residue can be dried and then outsourced or self-treated.

[0019] In some embodiments of the present application, the base is sodium hydroxide or an aqueous solution thereof.

[0020] In some embodiments of the present application, the excess base can be 10%-30% excess base. Further, the excess of base is set according to the content of triethylamine hydrochloride.

[0021] Further, the reaction formula of triethylamine hydrochloride and sodium hydroxide is approximately as follows:

[0022] (C2H5)3NH + Cl - +NaOH→(C2H5)3N+NaCl+H2O.

[0023] According to the present application, the alkaline hydrolysis reaction can promote the formation of a triethylamine-sodium chloride two-phase system, and then the oil phase and the water phase are obtained by standing.

[0024] In some embodiments of the present application, the standing time of the standing and layering can be 1-10h, further 2-6h, and more further 3-4h.

[0025] In some embodiments of the present application, the oil phase is subjected to rectification purification to obtain triethylamine. Further, the refined triethylamine is collected from the fraction of 80-90°C during the rectification purification, and is recovered for use in the production process.

[0026] In some embodiments of the present application, the pH value of the water phase is adjusted to 4-5 before the calcium peroxide is added. Further, the pH value of the water phase is adjusted to 4-5 by adding hydrochloric acid before the calcium peroxide is added. Still further, the concentration of the hydrochloric acid can be 1-10 mol / L, and in addition, the dropping speed of the hydrochloric acid can be 50-150 kg / h.

[0027] In some embodiments of the present application, the amount of the calcium peroxide added is controlled to be 10%-50% of the mass of the water phase. Further, the amount of the calcium peroxide added is controlled to be 15%-20% of the mass of the water phase.

[0028] In some embodiments of the present application, after the calcium peroxide is added, the temperature is controlled to be 30-40°C for stirring and mixing to prepare the pretreatment solution. Further, the stirring and mixing time is controlled to be 0.5-4 h, for example, 1 h, 2 h, 3 h, etc.

[0029] In some embodiments of the present application, during the acidification treatment, nitric acid is used for the acidification treatment, and further, the mass ratio of the activated carbon to the nitric acid is controlled to be 1:2-10, and the concentration of the nitric acid is controlled to be 5-16 mol / L.

[0030] According to some specific aspects of the present application, the mass ratio of the activated carbon to the nitric acid is controlled to be 1:4-6, and the concentration of the nitric acid is controlled to be 10-14 mol / L.

[0031] In some embodiments of the present application, the acidification treatment is controlled to be carried out at 70-90°C, for example, 75°C, 80°C, 85°C, 90°C, etc.

[0032] In some embodiments of the present application, the acidification treatment time is controlled to be 5-24 h, for example, 8 h, 10 h, 12 h, 16 h, etc.

[0033] In some embodiments of the present application, the washing and drying include multiple centrifugal washing of the acidified activated carbon with deionized water until the pH value approaches or reaches neutrality, and the washed product is transferred to a drying box (preferably a vacuum drying box) for drying treatment, and the drying temperature can be 80-120°C, and the drying time can be 5-24 h.

[0034] In some embodiments of the present application, the first calcination treatment and the second calcination treatment are both carried out in a tube furnace.

[0035] In some embodiments of the present application, the protective atmosphere is nitrogen and / or inert gas. Further, the inert gas can be argon, helium, etc.

[0036] In some embodiments of the present application, the temperature of the first calcination process is controlled to be 500-700℃, further 550-650℃, and more further 580-620℃. According to some specific aspects of the present application, the temperature of the first calcination process is controlled to be 580℃, 590℃, 600℃, 610℃, 620℃, etc.

[0037] In some embodiments of the present application, the temperature rising speed of the first calcination process is controlled to be 1-15℃ / min. Further, the temperature rising speed of the first calcination process can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min.

[0038] In some embodiments of the present application, the processing time of the first calcination process is controlled to be 0.5-2h, for example, can be 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h, etc.

[0039] In some embodiments of the present application, the divalent iron ion and / or trivalent iron ion is added in the form of a salt, further, in the form of ferrous nitrate and / or ferric nitrate, or aqueous solution thereof.

[0040] In some embodiments of the present application, the pre-processed activated carbon, divalent iron ion and / or trivalent iron ion is mixed in water at 60-80℃, preferably in a rotary evaporator, and then dried (the drying temperature can be 60-100℃), and then the second calcination process is performed.

[0041] In some embodiments of the present application, the temperature of the second calcination process is controlled to be 500-600℃, further 520-580℃. According to some specific aspects of the present application, the temperature of the second calcination process is controlled to be 530℃, 540℃, 550℃, 560℃, etc.

[0042] In some embodiments of the present application, the temperature rising rate of the second calcination treatment is controlled to be 1-15℃ / min. Further, the temperature rising rate of the second calcination treatment can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min.

[0043] In some embodiments of the present application, the treatment time of the second calcination treatment is controlled to be 2-8h, for example, can be 3h, 4h, 5h, 6h, etc.

[0044] In some embodiments of the present application, the electrochemical catalytic oxidation treatment adopts graphite as anode, and a constant potential of 0.1-1V is applied, for example, a constant potential of 0.2V, 0.3V, 0.4V, 0.5V, etc. can be applied.

[0045] In some embodiments of the present application, the feeding mass ratio of the catalyst, the binder and the conductive agent is 8-12:1:1-3.

[0046] According to a specific aspect of the present application, the feeding mass ratio of the catalyst, the binder and the conductive agent is 10:1:2.

[0047] In some embodiments of the present application, the mixture of the catalyst, the binder and the conductive agent after mixing is uniformly coated on the graphite felt in a coating manner, dried, and a modified graphite felt electrode is prepared.

[0048] In some embodiments of the present application, the post-treatment method further comprises: performing solid-liquid separation on the oxidized solution to remove insoluble impurities; and evaporating and crystallizing to obtain sodium chloride.

[0049] The present application also provides a technical solution: a modified graphite felt electrode, and a preparation method of the modified graphite felt electrode comprises:

[0050] The activated carbon is subjected to acidification treatment, washed and dried, and subjected to a first calcination treatment under a protective atmosphere to obtain pretreated activated carbon; the pretreated activated carbon, divalent iron ions and / or trivalent iron ions are mixed, dried, and subjected to a second calcination treatment under a protective atmosphere to obtain a catalyst, and the catalyst, a binder and a conductive agent are mixed and applied on a graphite felt to prepare a modified graphite felt electrode.

[0051] The present application also provides a technical solution: application of a modified graphite felt electrode in catalytic oxidation of organic wastewater, and the organic wastewater comprises water, salt and organic matter.

[0052] Furthermore, the organic wastewater is the aforementioned aqueous phase.

[0053] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0054] This invention addresses the shortcomings of existing methods for treating waste products from vinylene carbonate production, such as triethylamine hydrochloride residue, which are characterized by complex procedures, difficult operation, demanding conditions, high energy consumption, high investment costs, insufficient treatment efficiency, and inadequate stable operation. It innovatively provides an improved treatment method. This method includes a sequential alkaline hydrolysis reaction, separation of an aqueous phase and an oil phase, where the oil phase can be directly distilled to obtain triethylamine. The aqueous phase is pretreated by adding calcium peroxide, and then subjected to electrochemical catalytic oxidation under a cathode made of a specific modified graphite felt electrode. Practice has shown that this invention can achieve at least the following effects:

[0055] 1. The sodium chloride recovered as a byproduct of this invention, after net testing, has a purity that meets the first-grade standard for refined industrial wet salt in GB / T 5462-2015 Industrial Salt (NaCl ≥ 95.0%; moisture ≤ 3.5%; water-insoluble matter ≤ 0.1%; Ca...). 2+ +Mg 2+ Total amount ≤0.5%; SO4 2- With a salt content of ≤0.7%, this method achieves high-value recycling of waste salt, reducing production costs by ≥20% compared to traditional processes, while also reducing the discharge of salt-containing hazardous waste by more than 90%, thus combining economic efficiency with environmental friendliness.

[0056] 2. The oxidant used in this invention abandons the traditional oxidants (such as concentrated sulfuric acid and sodium hypochlorite) that are highly corrosive and environmentally unfriendly, and uses calcium peroxide as a green oxidation medium. It generates hydroxyl radicals (·OH) through in-situ hydrolysis and electrochemical catalytic two-electron oxygen reduction reaction, thereby achieving efficient oxidation of organic matter. At the same time, the by-product calcium chloride combines with carbonate to form calcium carbonate precipitate. The dual action achieves efficient oxidation of organic matter and simultaneous removal of carbonate, avoiding the risk of secondary pollution.

[0057] 3. This invention supports a porous iron-based activated carbon catalyst on a graphite felt electrode, which has a high specific surface area, abundant oxygen-containing functional groups on the surface, and uniformly dispersed Fe. 3+ / Fe 2+ Redox active sites. It efficiently catalyzes oxygen activation to generate hydroxyl radicals under normal pressure, achieving a TOC degradation rate of ≥90% for organic pollutants while avoiding the formation of unwanted precipitates.

[0058] In summary, the operation method of this invention is simple, easy to implement, highly continuous, low in cost, without high temperature and high pressure processes, and has excellent processing effect. Attached Figure Description

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0060] Figure 1 A flowchart of the treatment method of the vinylene carbonate production waste of the present application;

[0061] Figure 2 The N2 adsorption-desorption isotherm of Fe / ACH-600. DETAILED DESCRIPTION

[0062] The treatment method of the vinylene carbonate production waste provided by the present application focuses on the deficiencies in the prior art and makes targeted improvements, aiming to successfully realize the resource treatment of waste salt and make it be reasonably utilized.

[0063] Specifically, the treatment method of the vinylene carbonate production waste of the present application comprises:

[0064] The triethylamine hydrochloride waste residue is dispersed in water, filtered, and an excess of base is added to the filtrate for alkaline hydrolysis reaction, and then the mixture is left to separate into an oil phase and an aqueous phase, wherein the oil phase contains triethylamine;

[0065] Calcium peroxide is added to the aqueous phase, and the mixture is stirred to obtain a pretreated solution;

[0066] The pretreated solution is subjected to electrochemical catalytic oxidation treatment, and the modified graphite felt electrode is used as the cathode in the electrochemical catalytic oxidation treatment;

[0067] The addition amount of the calcium peroxide is controlled to be more than 10% of the mass of the aqueous phase;

[0068] The modified graphite felt electrode is prepared by the following method: the activated carbon is subjected to acidification treatment, washed and dried, and then subjected to first calcination treatment in a protective atmosphere to obtain pretreated activated carbon; the pretreated activated carbon, divalent iron ions and / or trivalent iron ions are mixed, dried, and then subjected to second calcination treatment in a protective atmosphere to obtain a catalyst; the catalyst, a binder and a conductive agent are mixed and then applied to the graphite felt to prepare the modified graphite felt electrode.

[0069] The following will be described in combination with Figure 1 The above treatment method will be further described:

[0070] Firstly, triethylamine hydrochloride waste residue is dissolved and dispersed in water, and after dissolution and dispersion, filtration is carried out, the amount of filter residue is small, and the filter residue after drying can be outsourced treatment, and at the same time, the filtrate is treated by adding an excess of sodium hydroxide aqueous solution to carry out alkaline hydrolysis reaction, so as to form a triethylamine-sodium chloride two-phase system, and oil-water phase separation is realized by standing;

[0071] The oil phase (oil layer) has less impurities, and can be directly purified by rectification, so that qualified triethylamine product can be obtained, and the triethylamine can be used for preparing vinylene carbonate, i.e. can be used for reacting with chloroethylene carbonate to prepare vinylene carbonate;

[0072] The water phase (water layer) contains water, sodium chloride and organic matter, and the pH value of the water phase is adjusted first, for example, hydrochloric acid can be added to adjust the pH value of the system, and the pH value can be adjusted to 4-5, and the residual alkaline components are neutralized;

[0073] Calcium peroxide is added to the water phase after adjusting the pH value, and the calcium peroxide is more easily dissolved in the adjusted water phase, and stirring is carried out at a certain temperature to obtain a pretreated solution;

[0074] The pretreated solution is transferred to an electrochemical catalytic oxidation system, a modified graphite felt electrode is used as a cathode, graphite is used as an anode, a constant potential is applied, hydroxyl radicals (·OH) are continuously generated by a cathode double-electron oxygen reduction reaction, and COD degradation is realized;

[0075] The oxidized solution is subjected to solid-liquid separation through a pressure filtration system to remove insoluble impurities;

[0076] Industrial-grade sodium chloride is obtained by evaporation and crystallization (there is also a separated mother liquor, in the present application, the removal rate of organic matter is high, water is easily evaporated, so the amount of crystallized sodium chloride is large, and the purity is high, and the mother liquor is small; in the prior art, due to the high content of organic matter, water is not easily evaporated, the amount of crystallized sodium chloride is small, and the purity is low, and the mother liquor after evaporation also contains a large amount of sodium chloride and organic matter), and the evaporated water in the evaporation process can be reused in the process of initially dispersing triethylamine hydrochloride waste residue.

[0077] The preparation method of the modified graphite felt electrode used in the present application comprises:

[0078] The activated carbon is subjected to acidification treatment, washing and drying, and first calcination treatment is carried out under a protective atmosphere to obtain pretreated activated carbon;

[0079] The pretreated activated carbon, divalent iron ions and / or trivalent iron ions are mixed, dried, and second calcination treatment is carried out under a protective atmosphere to obtain a catalyst;

[0080] The catalyst, a binder and a conductive agent are mixed and applied on the graphite felt to prepare a modified graphite felt electrode.

[0081] For example, the modified graphite felt electrode used in the following embodiments of the present application can be prepared according to the following method:

[0082] (1) Commercially available activated carbon (AC) can be used as raw material, and its BET surface area is about 869 m 2 / g;

[0083] When the commercially available activated carbon (AC) is mixed with nitric acid aqueous solution (12 mol / L) at a mass ratio of 1:5, and acidification treatment is carried out at 80°C for 12 hours, after the reaction is completed, the product is cooled to room temperature, and is marked as ACH, and its BET surface area is about 952 m 2 / g;

[0084] (2) The ACH sample is washed with deionized water by centrifugation for multiple times until the pH value approaches neutral;

[0085] (3) The washed sample is transferred to a vacuum drying oven and dried at 100°C for 12 hours;

[0086] (4) The dried ACH powder is placed in a tube furnace, and is heated to 500°C, 600°C and 700°C at a heating rate of 10°C / min under nitrogen atmosphere, respectively, and is naturally cooled to room temperature after being kept at constant temperature for 1 hour, and the obtained samples are marked as ACH-500, ACH-600 and ACH-700, respectively;

[0087] (5) The ACH series samples obtained in step (4) are mixed with 0.5 mol / L ferric nitrate aqueous solution, and after being mixed in a rotary evaporator at 70°C for 1 hour, the excess solvent is evaporated under vacuum;

[0088] (6) The loaded sample is placed in a blast drying oven and dried at 80°C for 10 hours;

[0089] (7) The dried sample is again placed in a tube furnace and heated to 550°C at a heating rate of 10°C / min under nitrogen protection, and is calcined at constant temperature for 5 hours, and finally obtained catalysts are marked as Fe / ACH-500, Fe / ACH-600 and Fe / ACH-700, respectively.

[0090] (8) The catalyst obtained in step (7) is mixed with polytetrafluoroethylene and carbon black at a mass ratio of 10:1:2, and then the mixture is uniformly coated on a graphite felt (3 cm x 4 cm). After being dried at 100°C for 12 hours, a modified graphite felt electrode is obtained.

[0091] The BET surface areas of ACH-500, ACH-600, ACH-700, Fe / ACH-500, Fe / ACH-600 and Fe / ACH-700 are shown in Table 1.

[0092] Table 1

[0093]

[0094] like Figure 2 As shown, the N2 adsorption-desorption isotherm of the Fe / ACH-600 catalyst exhibits a typical Type IV curve, with a BET specific surface area of ​​835 m². 2 / g. As shown in Table 1, nitric acid acidification significantly increased the specific surface area of ​​the activated carbon support, while subsequent heat treatment led to differentiated changes in specific surface area: the specific surface areas of ACH-500, ACH-600, and ACH-700 decreased to 749 m². 2 / g、885m 2 / g and 840m 2 / g. Notably, the catalyst's specific surface area further decreased with increasing metal loading, indicating that some metal particles were deposited within the micropores of the activated carbon.

[0095] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0096] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0097] Example 1

[0098] This example provides a method for treating waste from the production of vinylene carbonate, including the following steps:

[0099] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate 170g sodium hydroxide solution (mass concentration of about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine), rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 15% (relative to the mass content of water phase) of calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Fe / ACH-500 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, electrolysis reaction for 80 minutes, the oxidized water sample is filtered, evaporated and crystallized to obtain 64g sodium chloride (purity about 93.0wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 7589mg / L, COD removal rate is about 70.4%.

[0100] Example 2

[0101] The example provides a method for treating vinylene carbonate production waste, comprising the following steps:

[0102] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate 170g sodium hydroxide solution (mass concentration of about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine), rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 15% (relative to the mass content of water phase) of calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Fe / ACH-600 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, electrolysis reaction for 80 minutes, the oxidized water sample is filtered, evaporated and crystallized to obtain 64g sodium chloride (purity about 93.0wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 7589mg / L, COD removal rate is about 70.4%.

[0103] Example 3

[0104] The example provides a method for treating vinylene carbonate production waste, comprising the following steps:

[0105] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate 170g sodium hydroxide solution (mass concentration of about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine), rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 10% (relative to the mass content of water phase) calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Fe / ACH-600 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, electrolysis reaction for 80 minutes; the oxidized water sample is filtered, evaporated and crystallized to obtain 50g sodium chloride (purity about 85.0wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 7479mg / L, COD removal rate is about 70.8%.

[0106] Example 4

[0107] The example provides a method for treating vinylene carbonate production waste, comprising the following steps:

[0108] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate 170g sodium hydroxide solution (mass concentration of about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine), rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 10% (relative to the mass content of water phase) calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Fe / ACH-600 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, electrolysis reaction for 80 minutes; the oxidized water sample is filtered, evaporated and crystallized to obtain 50g sodium chloride (purity about 85.0wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 7479mg / L, COD removal rate is about 70.8%.

[0109] Comparative Example 1

[0110] The example provides a method for treating vinylene carbonate production waste, using the same preparation method as the iron-based activated carbon catalyst, replace the ferric nitrate aqueous solution with manganese nitrate aqueous solution, to prepare manganese-based activated carbon catalyst modified graphite felt electrode.

[0111] Specifically:

[0112] (1) Commercial activated carbon (AC) was added to nitric acid aqueous solution (12 mol / L) at a mass ratio of 1:5 and mixed, and acidification treatment was carried out at 80°C for 12 hours. After the reaction was completed, the obtained product was cooled to room temperature and labeled as ACH;

[0113] (2) The ACH sample was washed by centrifugation with deionized water for multiple times until the pH value was close to neutral;

[0114] (3) The washed sample was transferred to a vacuum drying oven and dried at 100°C for 12 hours;

[0115] (4) The dried ACH powder was placed in a tube furnace and heated to 500°C and 600°C at a heating rate of 10°C / min under nitrogen atmosphere, respectively. After constant temperature for 1 hour, the obtained sample was naturally cooled to room temperature, and the obtained sample was labeled as ACH-500 and ACH-600, respectively;

[0116] (5) The ACH series samples obtained in step (4) were mixed with 0.5 mol / L manganese nitrate aqueous solution, and after mixing in a rotary evaporator at 70°C for 1 hour, the excess solvent was evaporated under vacuum;

[0117] (6) The loaded sample was placed in a blast drying oven and dried at 80°C for 10 hours;

[0118] (7) The dried sample was again placed in a tube furnace and heated to 550°C at a heating rate of 10°C / min under nitrogen protection, and constant temperature calcination was carried out for 5 hours. The finally obtained catalyst was labeled as Mn / ACH-500 and Mn / ACH-600, respectively.

[0119] (8) The catalyst obtained in step (7) was mixed with polytetrafluoroethylene and carbon black at a mass ratio of 10:1:2, and then the mixture was uniformly coated on graphite felt (3 cm x 4 cm). After drying at 100°C for 12 hours, a modified graphite felt electrode was obtained.

[0120] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate added 170g sodium hydroxide aqueous solution (mass concentration is about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine) is obtained, rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 15% (relative to the mass content of water phase) calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Mn / ACH-500 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, continuous electrolysis reaction 80 minutes, the oxidized water sample is filtered, evaporated and crystallized to obtain 40g sodium chloride (purity about 75wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 11021mg / L, COD removal rate is about 57%.

[0121] Comparative example 2

[0122] The example provides a method for treating vinylene carbonate production waste, comprising the following steps:

[0123] Take 200g triethylamine hydrochloride waste residue dissolved in 500g water, after filtration, to the filtrate added 170g sodium hydroxide aqueous solution (mass concentration is about 32%) for alkaline hydrolysis reaction, standing for 4 hours, the oil phase (mainly containing triethylamine) is obtained, rectification purification, get qualified triethylamine. The water phase is added dropwise 4mol / L hydrochloric acid, adjust the pH value of water phase to 4.5±0.5, then add 15% (relative to the mass content of water phase) calcium peroxide, 40℃ constant temperature stirring 1 hour, the pretreated solution is transferred to electrochemical catalytic oxidation system, using Mn / ACH-500 modified graphite felt electrode as cathode, graphite as anode, apply 0.3V (vs. RHE) constant potential, continuous electrolysis reaction 80 minutes, the oxidized water sample is filtered, evaporated and crystallized to obtain 40g sodium chloride (purity about 75wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 11021mg / L, COD removal rate is about 57%.

[0124] Comparative example 3

[0125] The example provides a method for treating vinylene carbonate production waste, which is basically the same as example 1, the only difference is that no calcium peroxide is added, but oxygen is continuously introduced into the water phase (flow rate is 2L / min). Evaporated and crystallized to obtain 50g sodium chloride (purity about 82wt.%), COD waste salt water solution: 25630mg / L, oxidized water sample: 9227mg / L, COD removal rate is about 64%.

[0126] As used throughout this document and in the claims, the phrase "comprising" is to be construed as an open-ended term that means "including, but not limited to." As used herein, the term "consisting essentially of" means including the elements specified, but also including other elements that do not materially affect the basic and novel characteristics of the composition or method. The phrase "consisting of" excludes any element not specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0127] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application should be covered within the protection scope of the present application.

[0128] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as exactly that endpoint. Any values that fall within common ranges of values are to be construed as not outside the scope of the present application even though one or both of the endpoints of the range or value is not specifically recited.

Claims

1. A method for treating a vinylene carbonate production waste, the vinylene carbonate production waste including triethylamine hydrochloride waste residue, characterized by, The post-processing method comprises: triethylamine hydrochloride waste residue is dispersed in water, filtered, an excess of base is added to the filtrate to perform alkaline hydrolysis, and the mixture is allowed to stand and separate into an oil phase and an aqueous phase, wherein the oil phase comprises triethylamine; calcium peroxide is added to the aqueous phase, and the mixture is stirred to obtain a pretreated solution; the pretreated solution is subjected to electrochemical catalytic oxidation treatment, and a modified graphite felt electrode is used as a cathode in the electrochemical catalytic oxidation treatment; wherein the amount of calcium peroxide added is greater than 10% of the mass of the aqueous phase; the modified graphite felt electrode is prepared by the following method: active carbon is subjected to acidification treatment, washed, dried, and subjected to first calcination treatment in a protective atmosphere to obtain pretreated active carbon; the pretreated active carbon, divalent iron ions and / or trivalent iron ions are mixed, dried, and subjected to second calcination treatment in a protective atmosphere to obtain a catalyst; the catalyst, a binder and a conductive agent are mixed and applied to a graphite felt to prepare the modified graphite felt electrode.

2. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The triethylamine hydrochloride waste residue comprises triethylamine hydrochloride and organic matter, and the organic matter comprises vinylene carbonate and polymers, wherein the mass content of the organic matter in the triethylamine hydrochloride waste residue is greater than 5% and further ranges from 5% to 15%; the mass ratio of the triethylamine hydrochloride waste residue to the water ranges from 1:2 to 5; the base is sodium hydroxide or an aqueous solution thereof; and / or the oil phase is subjected to rectification and purification to obtain triethylamine.

3. The method for treating vinylene carbonate production waste according to claim 1, characterized by, Before the calcium peroxide is added, the pH value of the aqueous phase is adjusted to 4-5; and / or the amount of calcium peroxide added is controlled to be 10%-50% of the mass of the aqueous phase.

4. The method for treating vinylene carbonate production waste according to claim 1, characterized by, After the calcium peroxide is added, the temperature is controlled to be 30-40℃, and the mixture is stirred to prepare the pretreated solution; and / or the amount of calcium peroxide added is controlled to be 15%-20% of the mass of the aqueous phase.

5. The method for treating vinylene carbonate production waste according to claim 1, characterized by, In the acidification treatment, nitric acid is used for acidification treatment, and the mass ratio of the active carbon to the nitric acid is controlled to be 1:2-10, and the concentration of the nitric acid is controlled to be 5-16 mol / L; and / or the acidification treatment is controlled to be performed at 70-90℃; and / or the acidification treatment is controlled to be performed for 5-24 h.

6. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The protective atmosphere is nitrogen and / or an inert gas; and / or the temperature of the first calcination treatment is controlled to be 500-700℃, further 550-650℃, and more further 580-620℃; and / or the temperature rising speed of the first calcination treatment is controlled to be 1-15℃ / min; and / or the treatment time of the first calcination treatment is controlled to be 0.5-2 h.

7. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The divalent iron ions and / or trivalent iron ions are added in the form of a salt, and further in the form of ferrous nitrate and / or ferric nitrate, or an aqueous solution thereof; and / or the pretreated active carbon, divalent iron ions and / or trivalent iron ions are mixed in water at 60-80℃, preferably in a rotary evaporator, and then dried before the second calcination treatment.

8. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The temperature of the second calcination treatment is controlled to be 500-600 DEG C, further 520-580 DEG C; and / or, the temperature rising speed of the second calcination treatment is controlled to be 1-15 DEG C / min; and / or, the treatment time of the second calcination treatment is controlled to be 2-8 h.

9. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The electrochemical catalytic oxidation treatment adopts graphite as anode, and a constant potential of 0.1-1 V is applied; and / or, the mass ratio of the catalyst, the binder and the conductive agent is 8-12:1:1-3.

10. The method for treating vinylene carbonate production waste according to claim 1, characterized by, The post-treatment method further comprises: performing solid-liquid separation on the oxidized solution to remove insoluble impurities; and evaporating and crystallizing to obtain sodium chloride.

Images