Ammonium chloride wastewater resourceful treatment method

Abstract

The invention discloses an ammonium chloride wastewater resourceful treatment method which comprises the following steps: carrying out adsorption treatment on ammonium chloride wastewater to be treated by adopting an adsorption column filled with LSV-16 resin and an adsorption column filled with LS-75 resin, and obtaining qualified treatment liquid when the TOC content and the pigment content in effluent meet preset requirements; and carrying out rotary evaporation on the qualified treatment liquid to obtain a concentrated solution, then carrying out evaporative crystallization on the concentrated solution, and drying to obtain recovered ammonium chloride. According to the method, through selective interception of resin adsorption, low-temperature operation of rotary evaporation concentration and purity improvement of evaporative crystallization, a co-processing system of physical adsorption-concentration purification-crystallization separation is constructed, and the technical bottlenecks of low product purity, insufficient resource recovery rate and the like caused by organic matter interference in a traditional method are effectively overcome; a new path for recycling high-purity products is provided for resource utilization of the wastewater containing the organic matter ammonium chloride.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pharmaceutical wastewater treatment, and relates to a resource treatment method for ammonium chloride wastewater. BACKGROUND

[0002] 2-cyano-4-nitroaniline as a key intermediate for the synthesis of complex drug molecules, a large amount of ammonium chloride wastewater with complex components is generated in the production process. In the synthesis of the intermediate, a key step is the ammonolysis reaction, which is carried out by substituting cyano with cyanide salt and p-nitroaniline under the action of a specific catalyst. The reaction releases chloride ions, which combine with ammonium ions in the system to form ammonium chloride, resulting in a large amount of such wastewater in the production process. In addition to ammonium chloride, the wastewater also contains unreacted raw materials, organic matter, pigments and other by-products generated by side reactions. At the same time, the raw materials carry and the metal catalyst used in the reaction process will have trace amounts of metal impurities remaining.

[0003] At present, there are many methods for the treatment and recovery of ammonium chloride wastewater, including evaporation crystallization, membrane separation, cooling crystallization, chemical precipitation and biological treatment, etc. However, these methods have their own advantages and disadvantages. Although membrane separation has the advantages of low energy consumption, no phase change and simple operation, it has strict requirements for the water quality of the influent, the pretreatment process is complex, and the membrane assembly is easily contaminated, with high replacement cost. Biological treatment is only suitable for low-concentration wastewater, and high-concentration ammonium chloride wastewater can strongly inhibit and poison microorganisms, causing the treatment system to fail to operate normally and the treatment effect to be greatly reduced. The cooling crystallization method has lower energy consumption than the evaporation crystallization method, but the recovery rate is lower, and the control requirements for cooling temperature and cooling rate are extremely strict.

[0004] In addition, the existing technology has obvious limitations in practical application. The presence of a large amount of organic matter in ammonium chloride wastewater makes it difficult to achieve effective treatment and resource recycling of wastewater by relying on a single method, and it is difficult to obtain high-purity ammonium chloride products. For example, if membrane separation is used, organic matter may block the membrane pores, reducing separation efficiency; biological treatment is inhibited by high-concentration organic matter and ammonium chloride, and microorganisms cannot effectively degrade pollutants; the cooling crystallization method is affected by organic matter, and the crystallization process is difficult to control accurately, affecting the recovery rate and purity.

[0005] Therefore, it is necessary to develop a process method with high recovery rate, simple process, low running cost and environmental friendliness to achieve the dual goals of wastewater discharge and resource utilization. This not only helps to reduce production costs and environmental pollution, but also improves resource utilization efficiency and promotes the sustainable development of related industries. SUMMARY

[0006] In view of the problems in the prior art, the application provides a method for resourceful treatment of ammonium chloride wastewater, so as to solve the technical problem that a single method cannot effectively treat and realize resource reuse to obtain a high-purity product due to a large amount of organic matter in the wastewater in the prior art.

[0007] The application is realized by the following technical scheme: The method for resourceful treatment of ammonium chloride wastewater comprises the following steps: S1: using an adsorption column filled with LSV-16 resin and an adsorption column filled with LS-75 resin to perform adsorption treatment on the ammonium chloride wastewater to be treated, and obtaining qualified treatment liquid when the TOC content and the pigment content in the effluent reach preset requirements; S2: performing rotary evaporation on the qualified treatment liquid to obtain a concentrated liquid, then performing evaporation crystallization on the concentrated liquid, and obtaining recovered ammonium chloride after drying.

[0008] Further, the adsorption treatment of the ammonium chloride wastewater to be treated by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is specifically as follows: first, the adsorption column filled with LSV-16 resin is used to perform adsorption treatment on the ammonium chloride wastewater to be treated, when the TOC content in the effluent reaches the preset requirement, the effluent with the TOC content reaching the preset requirement is introduced into the adsorption column filled with LS-75 resin, when the pigment content in the effluent reaches the preset requirement, the qualified treatment liquid is obtained.

[0009] Further, the adsorption treatment of the ammonium chloride wastewater to be treated by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is specifically as follows: the ammonium chloride wastewater to be treated is sequentially introduced into the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin, and the qualified treatment liquid is obtained when the TOC content in the effluent and the pigment content in the effluent reach the preset requirements.

[0010] Further, the loading process of the adsorption column is specifically as follows: the LSV-16 resin and the LS-75 resin are pretreated, and the pretreated LSV-16 resin and the pretreated LS-75 resin are respectively introduced into a glass chromatographic column, and a water layer with a height of 3-5 cm is reserved above the LSV-16 resin and the LS-75 resin.

[0011] Further, in step S1, when the adsorption treatment of the ammonium chloride wastewater to be treated by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is performed, the flow rate of the ammonium chloride wastewater to be treated in the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is 1-12 BV / h.

[0012] Further, in step S1, when the content of TOC in the effluent of the adsorption column filled with LSV-16 resin exceeds a preset value or the content of pigment in the effluent of the adsorption column filled with LS-75 resin exceeds a preset value, the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are regenerated; the regeneration process of the adsorption column filled with LSV-16 resin is as follows: the feed liquid in the adsorption column is replaced by pure water, and then the adsorption column is treated by a desorbent, which is a NaOH solution, a methanol solution or a mixed solution of NaOH and methanol; finally, the adsorption column is cleaned by pure water again.

[0013] Further, the mass percentage concentration of the NaOH solution is 4%-10%, and the volume percentage concentration of the methanol solution is 50%-100%.

[0014] Further, in the process of replacing the feed liquid in the adsorption column by pure water, the amount of pure water used is 2-5 times the volume of the resin.

[0015] Further, the amount of the desorbent used is 3-10 times the volume of the resin; when the adsorption column is treated by the desorbent, the flow rate of the desorbent is 1-8 BV / h.

[0016] Further, in step S2, the volume of the concentrated liquid is 10%-20% of the volume of the qualified treatment liquid.

[0017] Compared with the prior art, the present application has the following beneficial technical effects: The present application discloses a method for resource treatment of ammonium chloride wastewater. First, in view of the difficulty in separation caused by the coexistence of organic matter and ammonium chloride in wastewater, selective separation is carried out by using a resin adsorption column. Through a dynamic adsorption process, the LSV-16 resin is used to specifically adsorb organic matter, so that the organic matter in the wastewater is intercepted in the adsorption column, while the ammonium chloride passes through the effluent. When the content of organic matter in the effluent exceeds a preset threshold (such as TOC>30ppm), the adsorption process is terminated in time to ensure the purity of the ammonium chloride solution. This step realizes the preliminary separation of organic matter and ammonium chloride through physical adsorption, avoiding the problem of reduced product purity caused by the coexistence of organic matter in traditional chemical precipitation or evaporation methods; then, the adsorption column filled with LS-75 resin is used to adsorb and treat the pigment in the treatment liquid, further realizing the regeneration of the treatment liquid. Secondly, the effluent containing high concentration of ammonium chloride after adsorption is concentrated by rotary evaporation, the boiling point is reduced by vacuum evaporation technology, and the solvent is efficiently removed under low temperature conditions, thereby minimizing the pollution of heat-sensitive organic matter to ammonium chloride. Subsequently, an evaporation crystallization process is used, which utilizes the property that the solubility of ammonium chloride changes with temperature, and by controlling the crystallization conditions, ammonium chloride is precipitated in the form of crystals, while the residual trace amount of organic matter remains in the mother liquor. Finally, solid ammonium chloride product is obtained by drying treatment, and the whole process realizes the complete separation of organic matter and ammonium chloride through staged separation (adsorption-concentration-crystallization).

[0018] The method constructs a synergistic treatment system of "physical adsorption-concentration purification-crystallization separation" through selective interception by resin adsorption, low-temperature operation by rotary evaporation concentration, and purity improvement by evaporation crystallization, effectively overcoming the technical bottlenecks of low product purity and insufficient resource recovery caused by organic matter interference in traditional methods, and providing a new path for high-purity product recovery in the resource utilization of ammonium chloride wastewater containing organic matter.

[0019] Further, the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are used for adsorption treatment of the ammonium chloride wastewater to be treated, specifically: first, the adsorption column filled with LSV-16 resin is used for adsorption treatment of the ammonium chloride wastewater to be treated, when the TOC content of the effluent reaches the preset requirement, the effluent with the TOC content reaching the preset requirement is introduced into the adsorption column filled with LS-75 resin, when the pigment content of the effluent reaches the preset requirement, the qualified treatment liquid is obtained; in addition, the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are used for adsorption treatment of the ammonium chloride wastewater to be treated, specifically: the ammonium chloride wastewater to be treated passes through the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin in sequence, when the TOC content of the effluent and the pigment content of the effluent reach the preset requirement, the qualified treatment liquid is obtained. Here, the two treatment methods are: the first one is that the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are connected in parallel (i.e. single column mode), and the second one is that the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are connected in series (i.e. series column mode), which effectively improves the flexibility of the method.

[0020] Further, the LSV-16 resin and the LS-75 resin are pretreated, and the pretreated LSV-16 resin and the pretreated LS-75 resin are respectively moved into the glass chromatographic column, and a water layer with a height of 3-5 cm is reserved above the LSV-16 resin and the LS-75 resin, so that the resin can maintain a wet state, avoid water loss and cracking, and also prevent air from entering the resin layer and affecting the adsorption effect.

[0021] Further, when the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are used for adsorption treatment of the ammonium chloride wastewater to be treated, the flow rate of the ammonium chloride wastewater to be treated in the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is 1-12 BV / h, so that the wastewater can have sufficient residence time in the resin for ion exchange.

[0022] Further, the regeneration process is that the feed liquid in the adsorption column is replaced by pure water, then the adsorption column is treated by a desorbent, and finally the adsorption column is cleaned by pure water again, so that the ion exchange capacity of the resin can be effectively recovered.

[0023] Further, during the process of replacing the feed liquid in the adsorption column by pure water, the amount of pure water used is 2-5 times the volume of the resin, so that the feed liquid in the adsorption column can be completely replaced by pure water.

[0024] Further, the amount of the desorbent used is 3-10 times the volume of the resin, and when the adsorption column is treated by the desorbent, the flow rate of the desorbent is 1-8 BV / h, so that the substances adsorbed on the resin can be completely eluted without affecting the subsequent reuse.

[0025] Further, in step S2, the volume of the concentrated solution is 10%-20% of the volume of the qualified treatment liquid, so that the solution can be in a supersaturated state, which is beneficial to the subsequent crystallization of ammonium chloride. DETAILED DESCRIPTION

[0026] In this document, all possible combinations of the technical features in each embodiment or example are not described in order to make the description simple. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined in any manner, and all possible combinations should be considered as the scope disclosed in this specification.

[0027] The application provides a resource treatment method for ammonium chloride wastewater, which comprises the following steps: (I) removal of organic matter, pigment and impurity metal ions by resin (1) resin pretreatment Before the resin is used, pretreatment is required, specifically, the resin is cleaned by pure water to ensure that the surface of the resin is free of pollutants and residual organic solvents, thereby providing a good basis for the subsequent adsorption process. The resin types used are LSV-16 and LS-75, which are purchased from Xi'an Lanshen New Material Technology Co., Ltd. During use, LSV-16 is used first to remove organic matter, and then LS-75 is used to remove the pigment in the effluent of LSV-16. In addition, the wastewater contains trace amounts of impurity metal ions, and the adsorption resin can remove the impurity metal ions while removing the organic matter and the pigment.

[0028] The resin LSV-16 is a styrene type macroporous adsorption resin, has large adsorption capacity and high adsorption precision, and the organic matter removal efficiency can reach more than 99%, and is more easily regenerated than ion exchange resin. Compared with other macroporous adsorption resins, the resin has large specific surface area and small average pore size.

[0029] The resin LS-75 is an anion exchange resin with primary amine groups, which has van der Waals force of styrene skeleton and chemical affinity of weak base groups, and can effectively adsorb substances with large molecular size.

[0030] (2) Resin filling A certain volume of pretreated resin is measured by a measuring cylinder, and is tamped to remove the voids between the resins and ensure the accuracy of filling. The tamped resin is moved into a glass chromatographic column to form an adsorption column, and a 3-5 cm water layer is maintained on the upper layer of the resin to prevent oxidation and other adverse reactions of the resin from contacting air in subsequent operations, and to ensure that the resin layer is free of bubbles to avoid affecting the adsorption effect. The height-diameter ratio of the glass chromatographic column is 14:1; The column passing mode adopts single column or column passing mode, and the column passing mode is up in and down out, a peristaltic pump is used to control the flow rate, and the treated liquid is added to ensure that the liquid passes through the resin layer uniformly and improve the adsorption efficiency.

[0031] (3) Adsorption process The flow rate of the treated liquid is 1-12 BV / h, where BV, i.e. bed volume (or column volume), is the volume multiple of the resin. For example, if the amount of resin filled is 50 mL, the column passing volume is 50 BV, which is 2500 mL of treated liquid, and the column liquid flow rate is 1 BV / h, which is 50 mL / h. The flow rate is adjusted according to the actual situation to achieve the best adsorption effect.

[0032] In this process, when the resin removes organic matter, pigments and impurities in the treated liquid, if the organic matter content and decolorization effect in the effluent do not meet the requirements, the adsorption is stopped to avoid unqualified liquid entering the subsequent treatment link.

[0033] (4) Resin regeneration: including replacing the liquid in the adsorption column with pure water; desorbing the substances adsorbed on the resin with a desorption agent; and washing the residual desorption agent in the resin with pure water. After the resin regeneration is completed, the next cycle of adsorption can be carried out. Specifically: Pure water displacement: The liquid in the adsorption column is replaced with pure water, and the volume of the pure water is 2-5 times the volume of the resin filled in the adsorption column, so as to ensure that the liquid in the column is fully displaced and prepared for the subsequent desorption step.

[0034] Desorption operation: the desorption of the substance adsorbed on the resin is carried out with a desorption agent, and the desorption agent is a NaOH solution, a methanol solution or a mixed solution of NaOH solution and methanol; wherein the mass percentage concentration (w / w) of the NaOH solution is 4%-10%, and the volume percentage concentration (v / v) of the methanol solution is 50%-100%; the volume of the desorption agent is 3-10 times the volume of the resin loaded in the adsorption column, and the flow rate of the desorption agent in the adsorption column, i.e. the regeneration flow rate, is 1-8 BV / h, and the appropriate desorption agent and desorption conditions are selected according to the properties and adsorption capacity of the resin.

[0035] Pure water cleaning: the residual desorption agent in the resin is cleaned with pure water, and the resin regeneration is completed, and the next cycle of adsorption can be carried out to ensure that the resin is not affected by the residual desorption agent in the next adsorption.

[0036] (II) Recovery of ammonium chloride by evaporation crystallization (1) Concentration crystallization: using a rotary evaporator, adjusting the appropriate temperature, and concentrating the above qualified liquid to a large amount of crystallization, stopping the rotary evaporation, and waiting for the temperature to drop to room temperature to obtain a solid-liquid mixture; specifically, using a rotary evaporator, adjusting the temperature to 70-90 DEG C, and concentrating the qualified liquid after resin treatment to 10%-20% of the original volume until white solids are produced, and stopping the rotary evaporation. The appropriate temperature and concentration degree can help to improve the crystallization efficiency and quality of ammonium chloride.

[0037] (2) Filtration separation: the solid-liquid mixture is filtered and separated to remove excess liquid to obtain a solid containing ammonium chloride crystals.

[0038] (3) Drying product: the solid containing ammonium chloride crystals obtained by filtration is placed in an oven for drying, and the drying temperature is 75-85 DEG C to obtain an industrial-grade ammonium chloride product. The appropriate drying temperature can avoid the decomposition of ammonium chloride and ensure the purity and quality of the product.

[0039] The present application provides a kind of ammonium chloride wastewater resource processing method, which is first carried out resin method, then carried out evaporation crystallization method, can simplify production process, reduce cost, improve ammonium chloride product quality and recovery rate. At the same time, the wastewater contains a variety of metal impurity ions, and the existing impurity removal process is complex and high in cost, and the macroporous adsorption resin provided by our company can remove impurity metal ions while removing organic matter, which can reduce the impurity content during evaporation crystallization, and is beneficial to improve the stability and purity of ammonium chloride product.

[0040] The application will be further described in connection with the following specific examples. It should be understood that the examples are intended to illustrate the application and are not intended to limit the scope of the application. Moreover, it should be understood that various modifications and changes can be made to the application by those skilled in the art upon reading the contents of this disclosure, and such equivalent forms are also within the scope of the appended claims.

[0041] The following examples use the apparatuses and devices that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are generally carried out according to the conventional conditions, or according to the conditions suggested by the manufacturers. The following examples use various raw materials, unless otherwise specified, all use conventional commercially available products, and the specifications are conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0042] Example 1 An ammonium chloride wastewater resource treatment method, comprising the following steps: (1) Removal of organic matter Resin packing Take a glass chromatographic column with a height-diameter ratio of 14:1, and use a measuring cylinder to take 50 mL of LSV-16 resin (for removing organic matter), i.e. the resin packing amount is 50 mL, which is dense, and move it into the glass chromatographic column with pure water to form an adsorption column, and keep 3-5 cm of water layer on the resin, and the resin has no air bubbles. The chromatographic column is fixed on the iron stand with a clamp, and connected with a silicone tube to a peristaltic pump, which is operated in a single column mode, and the flow rate is controlled by the peristaltic pump. Before using the LSV-16 resin, clean the impurities and residual organic reagents on the surface of the resin with pure water.

[0043] Removal of organic matter by resin (first cycle) The ammonium chloride wastewater to be treated is subjected to dynamic column treatment, and the flow rate is adjusted to 2 BV / h. Every two hours, the effluent is collected, and the TOC content is detected. The TOC content in the first 40 BV (i.e. 2000 mL) of effluent is lower than 30 ppm, and the TOC content in the 41-50 BV of effluent rapidly increases to 300 ppm, which does not meet the requirements, and the adsorption is stopped. The collected effluent is light yellow.

[0044] Resin regeneration (first cycle) The residual liquid in the resin column is replaced with 2 BV of pure water, and then the resin is desorbed with 4 BV of methanol solution at a flow rate of 1 BV / h. Finally, the resin is washed with pure water until the TOC content of the effluent is lower than 1 ppm.

[0045] Removal of organic matter by resin (second cycle) The regenerated resin was used to treat the ammonium chloride wastewater, and the flow rate was adjusted to 2 BV / h. The effluent was collected every 10 BV (i.e. 500 mL) to detect the TOC content. The results showed that the TOC content in the first 40 BV (i.e. 2000 mL) of effluent was about 30 ppm, and the TOC concentration of the subsequent effluent increased rapidly, and the solution color presented light yellow. The effect of resin on removing organic matter in the second cycle was the same as in the first cycle, and the adsorption performance of the resin did not decay.

[0046] Resin regeneration (second cycle) The regeneration method and the used desorbent were the same as in the first cycle.

[0047] Resin removal of organic matter (third cycle) The ammonium chloride wastewater was treated by dynamic column, and the flow rate was adjusted to 2 BV / h. The TOC content of 30 BV of effluent was detected to be lower than 30 ppm, and the TOC content of 40 BV of effluent was detected to be 40 ppm. The adsorption performance of the resin was slightly decayed compared with the previous two cycles.

[0048] (2) Removal of pigments The resin was filled with the same LSV-16 resin. In this step, LSV-75 was selected to remove pigments, i.e. decolorization.

[0049] Resin decolorization (first cycle) The effluent with TOC content lower than 40 ppm in step (1) was selected for decolorization treatment, and the dynamic column flow rate was 2 BV / h. The color of the effluent was observed until it changed from clear and transparent to light yellow, which indicated that the adsorption column was saturated and could not effectively adsorb the pigments in the treated liquid. Then the adsorption was stopped, and the transmittance was measured to be 100% by spectrophotometer. The concentration of various metal ions in the effluent was lower than 0.05 ppm.

[0050] Resin regeneration (first cycle) 2 BV of pure water was used to replace the residual liquid in the resin column. Then the resin was desorbed with mixed desorbent (6 BV of methanol + 1 BV of 4% NaOH solution) at a flow rate of 2 BV / h. Finally, the resin was washed with pure water until the pH of the effluent was less than 9.

[0051] Resin decolorization (second cycle) The effluent with TOC content lower than 40 ppm in step (1) was selected for decolorization treatment, and the dynamic column flow rate was 2 BV / h. 2 BV (i.e. 100 mL) of effluent was treated and presented yellow, which indicated that the resin was not effectively regenerated. The concentration of the desorbent was adjusted.

[0052] Resin regeneration (second cycle) The column was replaced with 2BV pure water to remove the residual liquid. Then the resin was desorbed with mixed desorbent (4BV methanol + 2BV 4% NaOH solution) at a flow rate of 1BV / h; the desorbent was replaced with 3BV pure water; and the resin was transformed with 2BV 4% NaOH solution at a flow rate of 1BV / h. Finally, the column was washed with pure water until the pH of the effluent was less than 9.

[0053] Resin decolorization (third cycle) The effluent with a TOC content of less than 40ppm in step (1) was selected for decolorization treatment, and the dynamic column flow rate was 2BV / h. The effluent was clear and transparent, with a light transmittance of 100%, and the concentration of various metal ions in the effluent was less than 0.05ppm.

[0054] (3) Recovery of ammonium chloride by evaporation crystallization The column effluent of step (1) and step (2) in Example 1 was concentrated by rotary evaporation at 85°C until a large amount of crystals appeared (about 10% to 20% of the original liquid volume). The stirring was stopped, and the temperature was reduced to room temperature. The solid-liquid mixture was transferred to a beaker and placed at low temperature for a night. The crystals were completely precipitated, and then filtered through a Buchner funnel. The product was dried in an oven at 80°C.

[0055] Specifically, 1L of the column effluent of step (1) in Example 1 was concentrated by rotary evaporation, filtered and dried to obtain 31.5g of light yellow ammonium chloride product. The product was light yellow ammonium chloride product due to the removal of pigments. The recovery rate was 78.75%.

[0056] Meanwhile, 1L of the column effluent of step (2) in Example 1 was concentrated by rotary evaporation, filtered and dried to obtain 33.6g of pure white ammonium chloride product, with a recovery rate of 84%.

[0057] The ammonium chloride product obtained above was dissolved in 100mL of pure water at a ratio of 1g of salt to 100mL of pure water. The TOC concentration was about 1ppm, and no metal ions were detected. It can be seen that the removal of organic matter by LSV-16 or the removal of pigments by LS-75 can effectively remove metal ions in the liquid to be treated.

[0058] In order to further verify the technical effects achieved by the present application, other resins were selected for verification under the same experimental conditions. The comparison is shown below: Comparative Example 1 Select other commercially available resin LS-106, LS-109D and the resin adsorption TOC effect comparison in step (1) of example 1, resin filling mode, filling amount and running mode with example 1, with pure water washing resin for standby. Among them, LS-106 and LS-109D are purchased from Shaanxi Lande Special Resin Co., Ltd.

[0059] Compared with the adsorption effect of LSV-16, when the TOC content of the effluent exceeds 30 ppm, the treatment capacity of the two resins is small, LS-109D can treat 15 BV, LS-106 can treat 30 BV, the solution is light yellow, and the concentration of various metal ions is less than 0.05 ppm.

[0060] Comparative example 2 Select other commercially available resin D301 and resin decolorization effect comparison in step (2) of example 1, resin filling mode, filling amount and running mode with example 1, with pure water washing resin for standby.

[0061] The resin D301 is a macroporous weak basic styrene anion exchange resin, which is a macroporous structure of styrene-divinylbenzene copolymer with tertiary amine group ion exchange resin, its basicity is weak, can effectively remove organic pigment, inorganic acid and silicate in acidic near neutral medium, and can adsorb impurities with large molecular size and be used in non-aqueous solution.

[0062] Select the effluent with TOC content less than 40 ppm after step (2) in example 1 for decolorization treatment, the dynamic column flow rate is 2 BV / h, the effluent is clear and transparent and the TOC concentration remains unchanged. Therefore, the resin is desorbed, first 2BV pure water is used to replace the feed liquid, then 4BV 4% NaOH solution is used to elute the substances on the resin, the flow rate is 1BV / h, finally the pure water is washed until the outlet pH is less than 9. The regenerated resin is used for the second period of decolorization test, the decolorization effect is poor, the effluent is darker than the inlet, the desorption of the resin in the previous period is not effective, the desorption method is changed: 4BV 4% hydrochloric acid, 6BV methanol and 2BV 4% NaOH solution are used in sequence, the flow rate is 1BV / h, finally the pure water is washed until the outlet pH is less than 9. The decolorization effect of the regenerated resin is still poor, the effluent is light yellow.

[0063] Comparative example 3 Recovery of ammonium chloride by evaporation crystallization The column liquid of comparative example 1 is concentrated by rotary evaporation at 85℃ until a large amount of crystals appear (about 10%~20% of the original liquid volume), stop stirring, and wait for the temperature to drop to room temperature. The solid-liquid mixture is transferred to a beaker and placed at low temperature overnight. After the crystals are completely precipitated, they are filtered through a Buchner funnel, and the product is dried in an oven at 80℃.

[0064] Specifically: 1 L of the column liquid in Comparative Example 1 was rotary evaporated, and ethanol was used for elution during filtration, and then dried to obtain 32.3 g of yellowish ammonium chloride product with a recovery rate of 80.75%.

[0065] The ammonium chloride product obtained above was dissolved in 100 mL of pure water at a ratio of 1 g of salt to 100 mL of pure water, and the TOC concentration was measured to be about 1 ppm, and no metal ions were detected.

[0066] Example 2 An ammonium chloride wastewater resource treatment method, comprising the following steps: Resin filling Two glass chromatography columns with a height-diameter ratio of 14:1 were taken, and 50 mL of LSV-16 and LS-75 resins were measured by a graduated cylinder, respectively, and then moved into the glass chromatography columns with pure water, and a fiber ball was added on top of the resins to filter suspended particulate matter, and a water layer of 3-5 cm was maintained on the resins without air bubbles. The chromatography columns were fixed on an iron stand with clamps, and the two resin columns of LSV-16 and LS-75 were connected in series with a silica gel tube, and the flow rate was controlled by a peristaltic pump.

[0067] Resin pretreatment The impurities and residual organic reagents on the surface of the resins were washed with pure water.

[0068] Resin adsorption The ammonium chloride wastewater was subjected to dynamic column adsorption, and the flow rate was adjusted to 2 BV / h. The effluent was collected every five hours, and the TOC content was detected. The TOC content in the first 50 BV (i.e. 2500 mL) of effluent was less than 30 ppm, and the solution was clear and transparent.

[0069] Resin regeneration The residual liquid in the resin column was replaced with 2 BV of pure water. The two resin columns were desorbed, and the LSV-16 resin column was desorbed with 4 BV of methanol solution, and the LS-75 resin column was desorbed with mixed desorbent (4 BV of methanol + 2 BV of 4% NaOH solution) and 2 BV of 4% NaOH solution, respectively, and the flow rate was 1 BV / h. Finally, the resin column was washed with pure water until the pH of the effluent was less than 9.

[0070] Resin cyclic adsorption The LSV-16 resin adsorption column was connected in series with the LS-75 resin adsorption column for cyclic adsorption, and the adsorption flow rate and resin regeneration method were the same as above. After 10 cycles, the resin adsorption column could treat 50 BV (i.e. 2500 mL) of solution, and the TOC content in the effluent was less than 30 ppm, the content of various metal ions was less than 0.05 ppm, and the solution was clear and transparent. The adsorption performance of the resin did not show any signs of degradation.

[0071] Evaporation and crystallization to recover ammonium chloride The qualified material liquid collected above was concentrated by rotary evaporator at 85℃ until a large amount of crystals appeared (about 15% of the original liquid volume), then the stirring was stopped, the temperature was reduced to room temperature, the solid-liquid mixture was transferred to a beaker, and was placed at low temperature overnight until the crystals were completely precipitated. Then the crystals were filtered by a Buchner funnel, and the product was dried in an oven at 80℃ for 4 hours.

[0072] Among them, 1L of qualified material liquid can obtain 38g of pure white ammonium chloride product, and the recovery rate is 95%. 1g of product is dissolved in 100mL of pure water, and the TOC concentration is less than 1ppm, and various metal ions are not detected.

[0073] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for resourceful treatment of ammonium chloride wastewater, characterized in that, The method comprises the following steps: S1: adsorbing the ammonium chloride wastewater to be treated by using an adsorption column filled with LSV-16 resin and an adsorption column filled with LS-75 resin, and obtaining a qualified treatment liquid when the TOC content and the pigment content in the effluent reach preset requirements; S2: rotary evaporating the qualified treatment liquid to obtain a concentrated liquid, evaporating and crystallizing the concentrated liquid, and drying to obtain recovered ammonium chloride.

2. The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, The adsorption treatment of the ammonium chloride wastewater to be treated by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is specifically as follows: first, the ammonium chloride wastewater to be treated is adsorbed by using the adsorption column filled with LSV-16 resin, and when the TOC content in the effluent reaches a preset requirement, the effluent with the TOC content reaching the preset requirement is introduced into the adsorption column filled with LS-75 resin, and when the pigment content in the effluent reaches a preset requirement, the qualified treatment liquid is obtained.

3. The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, The adsorption treatment of the ammonium chloride wastewater to be treated by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is specifically as follows: the ammonium chloride wastewater to be treated is sequentially passed through the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin, and when the TOC content in the effluent and the pigment content in the effluent reach preset requirements, the qualified treatment liquid is obtained.

4. The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, The loading process of the adsorption column is specifically as follows: the LSV-16 resin and the LS-75 resin are pretreated, and the pretreated LSV-16 resin and the pretreated LS-75 resin are respectively moved into a glass chromatographic column, and a water layer with a height of 3-5 cm is reserved above the LSV-16 resin and the LS-75 resin.

5. The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, In step S1, when the ammonium chloride wastewater to be treated is adsorbed by using the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin, the flow rate of the ammonium chloride wastewater to be treated in the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin is 1-12 BV / h.

6. The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, In step S1, when the TOC content in the effluent of the adsorption column filled with LSV-16 resin exceeds a preset value or the pigment content in the effluent of the adsorption column filled with LS-75 resin exceeds a preset value, the adsorption column filled with LSV-16 resin and the adsorption column filled with LS-75 resin are regenerated; the regeneration process of the adsorption column filled with LSV-16 resin is as follows: pure water is used to replace the liquid in the adsorption column, and then a desorption agent is used to treat the adsorption column, the desorption agent being a NaOH solution, a methanol solution, or a mixed solution of NaOH and methanol; finally, the adsorption column is cleaned again using pure water.

7. The ammonium chloride wastewater resourceful treatment method according to claim 6, characterized in that, The mass percentage concentration of the NaOH solution is 4%-10%, and the volume percentage concentration of the methanol solution is 50%-100%.

8. The ammonium chloride wastewater resourceful treatment method according to claim 6, characterized in that, In the process of replacing the liquid in the adsorption column with pure water, the amount of pure water used is 2-5 times the volume of the resin.

9. The ammonium chloride wastewater resourceful treatment method according to claim 6, characterized in that, The amount of the desorption agent used is 3-10 times the volume of the resin, and when the desorption agent is used to treat the adsorption column, the flow rate of the desorption agent is 1-8 BV / h. 10.The ammonium chloride wastewater resourceful treatment method according to claim 1, characterized in that, In step S2, the volume of the concentrated liquid is 10-20% of the volume of the qualified treatment liquid.