A process for purifying and treating ammonia-containing wastewater

Abstract

The invention relates to a purification process for ammonia-containing wastewater, and belongs to the technical field of sewage treatment. The process is based on a traditional stripping and ammonia evaporation process for heavy metal-containing high-ammonia nitrogen wastewater. A self-developed deamination agent is added in the stripping and ammonia evaporation process. The activated carbon is used as a carrier, and a thioether structure is grafted on the surface through modification. A titanium dioxide doped bismuth coordination hydrate is loaded on the surface by the complexation. The titanium dioxide surface has a large number of acid sites, which enhances the adsorption of activated carbon to ionic ammonium, and promotes the precipitation of free ammonia in coordination with the bismuth coordination hydrate. In addition, the thioether structure modification reduces the interfacial tension between sewage and the deamination agent, which is conducive to the infiltration of the deamination agent by the sewage, fully promotes the conversion of ionic ammonium into free ammonia, realizes efficient deamination under low alkalinity conditions, reduces the difficulty of post-treatment of deammoniation sewage, reduces the energy consumption of deamination, and reduces the corrosion of stripping and ammonia evaporation equipment. The process has far-reaching research significance for the research and development of low-energy consumption green deamination process.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular, relates to a purification process for ammonia-containing wastewater. Background Art

[0002] Ternary lithium battery is a lithium secondary battery that uses three transition metal oxides of nickel, cobalt and manganese as positive electrode materials. It fully combines the good cycle performance of lithium cobalt oxide, the high specific capacity of lithium nickel oxide and the high safety and low cost of lithium manganese oxide, and is widely used in power lithium batteries. Although it has excellent comprehensive performance, its positive electrode material will produce a large amount of wastewater containing high concentrations of ammonia nitrogen and metal ions during the production process. This type of wastewater discharged into the water body will not only cause eutrophication of the water body and cause the water body to be black and smelly, but also increase the difficulty and cost of water treatment, and even have a toxic effect on the human body and organisms. Usually, this type of wastewater must be treated to remove ammonia nitrogen and meet the standards before it can be discharged.

[0003] In the prior art, the ammonia nitrogen purification process mainly includes biological method and physicochemical method. Among them, the biological method is to convert ammonia nitrogen elements into nitrogen gas by nitrifying bacteria and release it. Its process cycle is long and it can only treat low-concentration ammonia nitrogen wastewater; the physicochemical method includes: ammonia evaporation (stripping), ion exchange, breakpoint chlorination, wet oxidation, chemical precipitation, membrane filtration and stripping method, etc. Ammonia evaporation and stripping method are more widely used. Among them, the stripping method is more suitable for the rough treatment of high-concentration ammonia nitrogen wastewater. The ammonia nitrogen residue in the treated wastewater is large, far from meeting the emission standards, and the post-treatment is difficult; ammonia evaporation is to directly or indirectly heat the wastewater with high-pressure steam to evaporate the ammonia and part of the water vapor in the wastewater. The process is relatively mature. However, in order to ensure that ionic ammonium is fully converted into free ammonia, the pH of the wastewater generally needs to be adjusted to above 11 during ammonia evaporation to ensure a good ammonia nitrogen removal rate. The amount of alkaline agents used is large and the equipment is seriously corrosive. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a purification process for ammonia-containing wastewater.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A purification process for ammonia-containing wastewater specifically comprises the following steps:

[0007] Step S1: pump the ammonia-containing wastewater into a sedimentation tank, add hydrogen peroxide and mix, and stir for 1.5-2h to form oxidized wastewater;

[0008] Furthermore, the ammonia nitrogen content of the ammonia-containing wastewater is not higher than 20000 mg / L, the amount of hydrogen peroxide used is 0.12-0.18 wt % of the ammonia-containing wastewater, and the hydrogen peroxide is used for oxidation pretreatment of the ammonia-containing wastewater.

[0009] Step S2: adding ammonia water to the oxidation wastewater to adjust the pH value to not less than 8, and recovering the filter cake by filter pressing, leaving the demetallized wastewater.

[0010] Step S3: adjusting the pH value of the demetallization wastewater to 10 with sodium hydroxide, adding a deamination agent and pumping the mixture into a stripping tower, controlling the air intake ratio to 0.13-0.16vvm, the air intake temperature to 140-150°C, the tower top temperature to 85-95°C, recovering the condensed ammonia water and pumping it into the oxidation wastewater for reuse, absorbing the ammonia-containing steam with hydrochloric acid to produce ammonium chloride, separating the stripping bottom liquid by ultra-gravity, and recovering the ammonia and the deamination agent;

[0011] Furthermore, the dosage of the deamination agent is 0.25-0.3wt% of the demetallization wastewater, and the deamination agent promotes the conversion of ionic ammonium in the demetallization wastewater into free ammonia to be stripped out.

[0012] The deamination agent is prepared by the following method:

[0013] Step A1: Dissolve the silane coupling agent KH580 in an ethanol solution under nitrogen protection, adjust the pH value to 3.5-4.5 with acetic acid, stir and hydrolyze for 0.8-1h, add activated carbon powder and ultrasonically disperse, let it stand for coupling for 12h, take the bottom precipitate, wash with water, and dry to obtain a thiol coupling carrier;

[0014] Furthermore, the dosage ratio of activated carbon micropowder, silane coupling agent KH580 and ethanol solution is 50g:5.5-7mL:75-95mL, the mass fraction of the ethanol solution is 40%, the silane coupling agent KH580 is hydrolyzed and coupled with the activated carbon micropowder, loaded onto the surface of the activated carbon micropowder, and organic groups containing active thiol groups are introduced into the surface layer for modification.

[0015] Step A2: Mix the thiol coupling carrier, 1,4-butanediol vinyl ether and acetone, control the temperature in a water bath to 45-55°C, stir and react under ultraviolet irradiation for 20-30 minutes, then add ethanedithiol and dimethylphenylphosphine in ethanol solution intermittently, and control the total reaction time to be 2.5-3 hours. After the reaction is completed, centrifuge to obtain the precipitate and evaporate to dryness under reduced pressure to obtain the thioetherified carrier;

[0016] Furthermore, the dosage ratio of the thiol coupling carrier, 1,4-butanediol vinyl ether, ethanedithiol, dimethylphenylphosphine and acetone is 50g:45-60mmol:25-35mmol:15-20mg:80-100mL, 1,4-butanediol vinyl ether and the thiol coupling carrier are click-added, and then ethanedithiol is used as a chain transfer agent to continue the click reaction, and the chain is extended on the surface of the activated carbon to form a thioether structure modification.

[0017] Step A3: ultrasonically disperse the thioetherified carrier, bismuth trichloride and dimethylacetamide aqueous solution, control the temperature in an ice-water bath to 5-15°C, slowly add titanium tetrachloride under dry nitrogen protection and ultrasonic vibration, let stand for 12 hours after complete addition, wash the bottom precipitate with water, and dry to obtain a deamination agent;

[0018] Furthermore, the dosage ratio of the thioetherification carrier, bismuth trichloride, titanium tetrachloride and dimethylacetamide aqueous solution is 50g: 0.15-0.2g: 0.5-0.7mL, 120-150mL, the mass fraction of the dimethylacetamide aqueous solution is 50%, bismuth trichloride decomposes into bismuth ions in the dimethylacetamide aqueous solution, and the bismuth ions coordinate with water molecules to form hydrates with various coordination numbers, which promote the conversion of ionic ammonium to free ammonia. Titanium tetrachloride is hydrolyzed under an ultrasonic environment to form titanium dioxide with a micro-nano structure, and the surface of the titanium dioxide has a large number of acid sites, which enhances the adsorption of the activated carbon matrix to ionic ammonium, and at the same time cooperates with the coordinated hydrate of bismuth to promote the precipitation of free ammonia. The thioether structure on the surface of the thioetherification carrier fixes the bismuth hydrate and titanium dioxide near the surface of the activated carbon through complexation, and the surface modification of the thioether structure can reduce the interfacial tension between the sewage and the deamination agent, which is beneficial to the deamination agent to fully treat the sewage.

[0019] Beneficial effects of the present invention:

[0020] The invention is based on the traditional steam stripping and ammonia evaporation process of heavy metal-containing high-ammonia nitrogen wastewater. A self-developed deamination agent is added in the steam stripping and ammonia evaporation process to achieve efficient deamination under low alkalinity conditions, reduce the difficulty of post-treatment of deammoniation wastewater, reduce deamination energy consumption, and reduce corrosion to steam stripping and ammonia evaporation equipment. The invention has far-reaching research significance for the research and development of low-energy consumption green deamination processes. The deamination agent uses activated carbon as a carrier, is modified by a silane coupling agent KH580, and active thiol groups are grafted on the surface. Then, 1,4-butanediol vinyl ether is click-added to the surface thiol groups, and ethanedithiol is used as a chain transfer agent to continue the click reaction, and chain growth is carried out on the surface of the activated carbon to form thioether bonds. The structure is modified by utilizing the complexing effect of the structure. The bismuth coordinated hydrate doped with titanium dioxide is hydrolyzed in a dimethylacetamide aqueous solution environment. The titanium dioxide surface has a large number of acid sites, which enhances the adsorption of ionic ammonium by the activated carbon matrix. At the same time, the bismuth coordinated hydrate promotes the precipitation of free ammonia. In addition, the thioether structure modification reduces the interfacial tension between the sewage and the deamination agent, which is beneficial for the deamination agent to be infiltrated by the sewage, fully promoting the conversion of ionic ammonium to free ammonia, thereby promoting the evaporation of free ammonia. In the test, the pH value of the stripping and ammonia evaporation environment reached 10, and the ammonia nitrogen removal rate of high-concentration wastewater with an ammonia nitrogen content of 18500 mg / L could reach 98.83-99.24%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention is based on the treatment of high ammonia nitrogen wastewater generated in the production process of ternary positive electrode materials. During the implementation process, sewage with an ammonia nitrogen content of 18500 mg / L is used as the test object. The specific implementation process is as follows: Example

[0025] 1) Preparation of deamination agent

[0026] Step A1: Prepare a 40% ethanol solution by mass, mix the silane coupling agent KH580 and the ethanol solution under nitrogen protection, add acetic acid to adjust the pH value to 3.5, stir and hydrolyze at 150rpm for 0.8h, then add activated carbon powder. During the implementation process, 325 mesh wood powder activated carbon from Henan Zhongli Activated Carbon Co., Ltd. was used, ultrasonically dispersed at 28kHz for 20min, and then allowed to stand for coupling for 12h. In the reaction, the amount ratio of activated carbon powder, silane coupling agent KH580 and ethanol solution was 50g:5.5mL:95mL. Finally, the bottom precipitate was washed with water and dried to obtain a thiol coupling carrier.

[0027] Step A2: Take the thiol coupling carrier, 1,4-butanediol vinyl ether and acetone and mix them. The water bath temperature is controlled at 55°C. A UVA light source is used at 250W / m 2The irradiation was carried out at a high intensity, and the reaction was irradiated for 20 minutes. Then, ethanedithiol and 1.2 times its mass of ethanol were mixed, and dimethylphenylphosphine was added to be mixed. The dissolved solution was divided into three equal parts, and added to the reaction system intermittently for 15 minutes. After the addition was complete, the irradiation reaction was continued at a constant temperature, and the total reaction time of the dissolved solution was controlled to be 2.5 hours. In the reaction, the amount ratio of thiol coupling carrier, 1,4-butanediol vinyl ether, ethanedithiol, dimethylphenylphosphine and acetone was 50g:45mmol:25mmol:20mg:100mL. After the reaction was completed, the precipitate was centrifuged and evaporated to dryness under reduced pressure to obtain a thioetherified carrier.

[0028] Step A3: prepare a 50% mass fraction of dimethylacetamide aqueous solution, take the thioetherification carrier, bismuth trichloride and dimethylacetamide aqueous solution and ultrasonically disperse them at 28kHz for 25min, control the temperature of the ice-water bath to 15°C, introduce dry nitrogen for protection, maintain ultrasonic oscillation for 15min, slowly add titanium tetrachloride, and let it stand for 12h after complete addition. In the reaction, the amount ratio of the thioetherification carrier, bismuth trichloride, titanium tetrachloride and dimethylacetamide aqueous solution is 50g:0.15g:0.7mL, 120mL, and finally wash the bottom precipitate with water and dry it to obtain a deamination agent.

[0029] 2) Wastewater purification

[0030] Step S1: Pump the ammonia-containing wastewater into the sedimentation tank, take 0.18wt% hydrogen peroxide from the ammonia-containing wastewater, dilute the ammonia-containing wastewater and add the mixture, stir at 60rpm for 1.5h, the residual divalent iron in the wastewater and hydrogen peroxide work synergistically to oxidize the ammonia-containing wastewater, which is beneficial to the subsequent sedimentation of the metal residues, and at the same time encapsulates the ammonia nitrogen structure to form oxidized wastewater.

[0031] Step S2: Add the recovered ammonia water to the oxidation wastewater to adjust the pH value to 8.2, filter press to recover the filter cake, and leave the demetallized wastewater.

[0032] Step S3: adjust the pH value of the demetallized wastewater to 10 with sodium hydroxide, add 0.25wt% of the deamination agent to the demetallized wastewater, and pump the mixture into a stripping tower, introduce 140°C hot air for stripping, control the air intake ventilation ratio to 0.13vvm, and the tower top temperature to 85°C. Condensate ammonia water for recovery, and partially pump it into oxidation wastewater to adjust the pH and settle. Absorb the ammonia-containing steam with hydrochloric acid to produce ammonium chloride, separate the stripping bottom liquid by ultra-gravity, and recover the ammonia and deamination agent to complete the purification of the ammonia-containing wastewater. Example

[0033] 1) Preparation of deamination agent

[0034] Step A1: Prepare a 40% ethanol solution by mass, mix the silane coupling agent KH580 and the ethanol solution under nitrogen protection, add acetic acid to adjust the pH value to 4, stir and hydrolyze at 120 rpm for 0.9 h, then add activated carbon powder, ultrasonically disperse at 28 kHz for 20 min, and then stand for coupling for 12 h. In the reaction, the amount ratio of activated carbon powder, silane coupling agent KH580 and ethanol solution is 50 g: 6.5 mL: 85 mL. Finally, the bottom precipitate is washed with water and dried to obtain a thiol coupling carrier.

[0035] Step A2: Take the thiol coupling carrier, 1,4-butanediol vinyl ether and acetone and mix them. The water bath temperature is controlled at 50°C. A UVA light source is used at 250W / m 2 The irradiation was carried out at a high intensity, and the irradiation reaction was performed for 22 minutes. Then, ethanedithiol and 1.3 times its mass of ethanol were mixed, and dimethylphenylphosphine was added to be mixed. The dissolved solution was divided into three equal parts, and added to the reaction system intermittently for 18 minutes. After the addition was complete, the irradiation reaction was continued at a constant temperature, and the total reaction time of the dissolved solution was controlled to be 2.8 hours. In the reaction, the amount ratio of thiol coupling carrier, 1,4-butanediol vinyl ether, ethanedithiol, dimethylphenylphosphine and acetone was 50g:50mmol:30mmol:20mg:90mL. After the reaction was completed, the precipitate was centrifuged and evaporated to dryness under reduced pressure to obtain a thioetherified carrier.

[0036] Step A3: prepare a 50% mass fraction of dimethylacetamide aqueous solution, take the thioetherification carrier, bismuth trichloride and dimethylacetamide aqueous solution and ultrasonically disperse them at 28kHz for 25min, control the temperature of the ice-water bath to 10°C, introduce dry nitrogen for protection, maintain ultrasonic oscillation for 25min, slowly add titanium tetrachloride, and let it stand for 12h after complete addition. In the reaction, the amount ratio of the thioetherification carrier, bismuth trichloride, titanium tetrachloride and dimethylacetamide aqueous solution is 50g:0.2g:0.5mL, 150mL, and finally wash the bottom precipitate with water and dry it to obtain a deamination agent.

[0037] 2) Wastewater purification

[0038] Step S1: Pump the ammonia-containing wastewater into a sedimentation tank, take 0.15wt% hydrogen peroxide of the ammonia-containing wastewater, dilute the ammonia-containing wastewater, add and mix, and stir at 60rpm for 1.7h to form oxidized wastewater.

[0039] Step S2: Add the recovered ammonia water to the oxidation wastewater to adjust the pH value to 8.5, filter press to recover the filter cake, and leave the demetallized wastewater.

[0040] Step S3: adjust the pH value of the demetallized wastewater to 10 with sodium hydroxide, add 0.28wt% of the deamination agent to the demetallized wastewater, and pump the mixture into a stripping tower, introduce 150°C hot air for stripping, control the air intake ventilation ratio to 0.15vvm, and the tower top temperature to 95°C. Condensate ammonia water for recovery, and partially pump it into the oxidation wastewater to adjust the pH and settle. Absorb the ammonia-containing steam with hydrochloric acid to produce ammonium chloride, separate the stripping bottom liquid by ultra-gravity, and recover the ammonia and the deamination agent to complete the purification of the ammonia-containing wastewater. Example

[0041] 1) Preparation of deamination agent

[0042] Step A1: Prepare a 40% ethanol solution by mass, mix the silane coupling agent KH580 and the ethanol solution under nitrogen protection, add acetic acid to adjust the pH value to 4.5, stir and hydrolyze at 120rpm for 1h, then add activated carbon powder, ultrasonically disperse at 28kHz for 20min, and then stand for coupling for 12h. In the reaction, the amount ratio of activated carbon powder, silane coupling agent KH580 and ethanol solution is 50g:7mL:75mL. Finally, the bottom precipitate is washed with water and dried to obtain a thiol coupling carrier.

[0043] Step A2: Take the thiol coupling carrier, 1,4-butanediol vinyl ether and acetone and mix them, control the temperature of the water bath at 45°C, use a UVA light source at 200W / m 2 The irradiation was carried out at a high intensity, and the irradiation reaction was performed for 30 minutes. Then, ethanedithiol and 1.5 times its mass of ethanol were mixed, and dimethylphenylphosphine was added to be mixed. The dissolved solution was divided into three equal parts, and added to the reaction system intermittently for 20 minutes. After the addition was complete, the irradiation reaction was continued at a constant temperature, and the total reaction time of the dissolved solution was controlled to be 3 hours. In the reaction, the amount ratio of thiol coupling carrier, 1,4-butanediol vinyl ether, ethanedithiol, dimethylphenylphosphine and acetone was 50g:60mmol:35mmol:15mg:80mL. After the reaction was completed, the precipitate was centrifuged and evaporated to dryness under reduced pressure to obtain a thioetherified carrier.

[0044] Step A3: prepare a 50% mass fraction of dimethylacetamide aqueous solution, take the thioetherification carrier, bismuth trichloride and dimethylacetamide aqueous solution and ultrasonically disperse them at 28kHz for 30min, control the temperature of the ice water bath to 5°C, introduce dry nitrogen for protection, maintain ultrasonic oscillation for 25min, slowly add titanium tetrachloride, and let it stand for 12h after complete addition. In the reaction, the amount ratio of the thioetherification carrier, bismuth trichloride, titanium tetrachloride and dimethylacetamide aqueous solution is 50g:0.17g:0.65mL, 150mL, and finally wash the bottom precipitate with water and dry it to obtain a deamination agent.

[0045] 2) Wastewater purification

[0046] Step S1: Pump the ammonia-containing wastewater into a sedimentation tank, take 0.12 wt% hydrogen peroxide from the ammonia-containing wastewater, dilute the ammonia-containing wastewater, add the mixture, and stir at 60 rpm for 2 hours to form oxidized wastewater.

[0047] Step S2: Add the recovered ammonia water to the oxidation wastewater to adjust the pH value to 8.5, filter press to recover the filter cake, and leave the demetallized wastewater.

[0048] Step S3: adjust the pH value of the demetallized wastewater to 10 with sodium hydroxide, add 0.3wt% of the deamination agent to the demetallized wastewater, and pump the mixture into a stripping tower, introduce 150°C hot air for stripping, control the air intake ventilation ratio to 0.16vvm, and the tower top temperature to 95°C. Condensate ammonia water for recovery, and partially pump it into the oxidation wastewater to adjust the pH and settle. Absorb the ammonia-containing steam with hydrochloric acid to produce ammonium chloride, separate the stripping bottom liquid by ultra-gravity, and recover the ammonia and deamination agent to complete the purification of the ammonia-containing wastewater.

[0049] Comparative Example 1

[0050] This comparative example is an existing ammonia evaporation process. The specific wastewater treatment process is the same as that of Example 3. In step S3, no deamination agent is added, and the rest is exactly the same.

[0051] Comparative Example 2

[0052] This comparative example is a reference treatment process of Example 3. In step S3, the pH value of the demetallized wastewater is adjusted to 11.5 with sodium hydroxide, and the rest is exactly the same.

[0053] Comparative Example 3

[0054] This comparative example is a parallel comparative treatment process of Example 3. In step S3, no deamination agent is added, and 0.4wt% of activated carbon and 0.05wt% of 1250 mesh anatase titanium dioxide are added to the demetallization wastewater. The rest are exactly the same.

[0055] Take the stripping bottom liquid after the above treatment, and use Nessler's reagent spectrophotometry to detect the ammonia nitrogen content in the treated wastewater. The removal rate is calculated as (ammonia nitrogen content before treatment - ammonia nitrogen content after treatment) / ammonia nitrogen content before treatment × 100%. The specific test results are shown in Table 1:

[0056] Table 1

[0057]

[0058] From the comparison of the above test results, it can be seen that the ammonia nitrogen removal rate of the embodiment treatment is 98.83-99.24%, among which, after 18500 mg / L sewage is treated by Example 3, the ammonia nitrogen content has reached the 150 mg / L indicator specified in the comprehensive sewage discharge standard; in Example 1, ammonia is evaporated under a low alkalinity pH of 10, and the removal rate is only 76.19%. Compared with Example 1, the pH value of Example 2 is increased to 11.5, and the ammonia nitrogen removal rate reaches 95.12%, indicating that properly increasing the alkalinity of the wastewater to evaporate ammonia is conducive to the evaporation of free ammonia; in Example 3, the removal rate is improved compared with Example 1 by using activated carbon and titanium dioxide for low alkalinity ammonia evaporation, indicating that activated carbon and titanium dioxide have a certain promoting effect on the removal of ammonia nitrogen, but the removal rate is still low, and subsequent treatment is difficult.

[0059] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A process for purifying ammonia-containing wastewater, It is characterized in that Including the following processes: Step S1: pump the ammonia-containing wastewater into a sedimentation tank, add hydrogen peroxide and mix, and stir for 1.5-2h to form oxidized wastewater; Step S2: adding ammonia water to the oxidation wastewater to adjust the pH value to not less than 8, and recovering the filter cake by filter pressing, leaving the demetallized wastewater; Step S3: adjusting the pH value of the demetallization wastewater to 10 with sodium hydroxide, adding a deamination agent, and pumping the mixture into a stripping tower for stripping and ammonia evaporation, condensing ammonia water for recovery and pumping into oxidation wastewater for reuse, absorbing ammonia-containing steam with hydrochloric acid to produce ammonium chloride, separating the stripping bottom liquid by ultra-gravity, and recovering ammonia and deamination agent; The deamination agent is prepared by the following method: Step A1: Dissolve the silane coupling agent KH580 in an ethanol solution under nitrogen protection, adjust the pH value to 3.5-4.5 with acetic acid, stir and hydrolyze for 0.8-1h, add activated carbon powder and ultrasonically disperse, let it stand for coupling for 12h, take the bottom precipitate, wash with water, and dry to obtain a thiol coupling carrier; Step A2: Mix the thiol coupling carrier, 1,4-butanediol vinyl ether and acetone, control the temperature in a water bath to 45-55°C, stir and react under ultraviolet irradiation for 20-30 minutes, then add ethanedithiol and dimethylphenylphosphine in ethanol solution intermittently, and control the total reaction time to be 2.5-3 hours. After the reaction is completed, centrifuge to obtain the precipitate and evaporate to dryness under reduced pressure to obtain the thioetherified carrier; Step A3: Ultrasonic dispersion of the thioetherified carrier, bismuth trichloride and dimethylacetamide aqueous solution, control the temperature at 5-15°C in an ice-water bath, protect with dry nitrogen and slowly add titanium tetrachloride under ultrasonic vibration. After complete addition, let stand for 12 hours, take the bottom precipitate, wash with water, and dry to obtain a deamination agent.

2. A process for purifying ammonia-containing wastewater according to claim 1, It is characterized in that The ammonia nitrogen content of the ammonia-containing wastewater is not higher than 20,000 mg / L, and the amount of hydrogen peroxide used is 0.12-0.18 wt% of the ammonia-containing wastewater.

3. A process for purifying ammonia-containing wastewater according to claim 1, It is characterized in that The dosage ratio of activated carbon powder, silane coupling agent KH580 and ethanol solution is 50g:5.5-7mL:75-95mL, and the mass fraction of the ethanol solution is 40%.

4. A process for purifying ammonia-containing wastewater according to claim 3, It is characterized in that The usage ratio of the thiol coupling carrier, 1,4-butanediol vinyl ether, ethanedithiol, dimethylphenylphosphine and acetone is 50g:45-60mmol:25-35mmol:15-20mg:80-100mL.

5. A process for purifying ammonia-containing wastewater according to claim 4, It is characterized in that The dosage ratio of the thioetherification carrier, bismuth trichloride, titanium tetrachloride and dimethylacetamide aqueous solution is 50g: 0.15-0.2g: 0.5-0.7mL, 120-150mL, and the mass fraction of the dimethylacetamide aqueous solution is 50%.

6. A process for purifying ammonia-containing wastewater according to claim 5, It is characterized in that The dosage of the deamination agent is 0.25-0.3wt% of the demetallization wastewater.

7. A process for purifying ammonia-containing wastewater according to claim 6, It is characterized in that During the stripping and distilling of ammonia, the inlet ventilation ratio is 0.13-0.16vvm, the inlet temperature is 140-150°C, and the tower top temperature is 85-95°C.

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