Catalysts and methods for treating hydrazine-containing wastewater

Abstract

The present invention relates to the field of environmental protection technology, and in particular to a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater. The catalyst comprises a composite catalyst; the composite catalyst comprises Cu 2+ , while containing Fe 2+ 、Al 3+ , Mn 2+ any one or more metal cation aqueous solutions in the reaction tank; the reaction device comprises a reaction tank, a catalyst storage tank, a water inlet pump, a pipeline mixer and a reflux device; the input end of the water inlet pump is connected to the device for storing hydrazine-containing wastewater, and the output end is connected to the pipeline mixer; the catalyst storage tank is connected to the pipeline mixer, and the output end of the pipeline mixer is connected to the reaction tank; the reflux device comprises a reflux pump; the input end of the reflux pump is connected to the upper part of the reaction tank, and the output end is connected to the bottom of the reaction tank; the treatment method uses the above catalyst and the reaction device to treat hydrazine-containing wastewater, has excellent treatment efficiency and treatment effect, and will not cause secondary pollution.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater. Background Art

[0002] Hydrazine, also known as hydrazine, is a colorless oily liquid with a pungent smell similar to ammonia. It is a highly polar compound that can be well soluble in polar solvents such as water and alcohol. Hydrazine also has strong reducing properties. It can not only reduce metal ions such as silver and nickel into metals, which are used for mirror silver plating, metal film plating on plastics and glass, but also corrode glass, rubber, leather, cork, etc. In addition, hydrazine, as an important fine chemical raw material, is mainly used for synthetic foaming agents, anti-corrosion additives for circulating water in thermal power plants and nuclear power plants; it is also widely used as a deoxidizer for water in industrial boilers and high-pressure steam furnaces. At the same time, with the rapid development of industry, the application scope of hydrazine is also constantly expanding, and the amount of hydrazine-containing wastewater is also increasing. In order to prevent hydrazine-containing wastewater from polluting the environment, it is of great significance to choose a more economical and reasonable treatment method.

[0003] Hydrazine in wastewater can be treated by a variety of methods, such as oxidation, chemical precipitation, evaporation concentration and crystallization, biological treatment, etc.; since hydrazine is a strong reducing agent and can automatically decompose in the presence of a catalyst, the oxidation method is an effective and simple treatment method for treating hydrazine in wastewater, which has been widely used. That is, the principle of redox reaction between oxidant and hydrazine is used to convert hydrazine into a harmless substance, thereby achieving the purpose of purifying hydrazine-containing wastewater. There are many methods for treating hydrazine-containing wastewater using this reaction principle, including natural purification, chlorination, air oxidation, ozone oxidation, potassium permanganate oxidation, catalytic air oxidation, etc.; however, among these methods, although the natural purification method has a simple operation method, low investment, and does not consume chemical reagents, it has a long treatment cycle and low treatment efficiency, and is rarely used alone; the chlorination method and potassium permanganate oxidation method will produce strong carcinogens, such as nitrosamines, causing secondary pollution; the ozone oxidation method requires an expensive ozone generator, and ozone is unstable at room temperature, which limits its applicability and increases the treatment cost; the air oxidation method has poor application effect in the actual treatment process of hydrazine-containing industrial wastewater; the catalytic air oxidation method has a simple and controllable reaction process, good cleaning performance, and high treatment efficiency, but the cost of the commonly used precious metal catalysts is relatively high, which greatly increases the treatment cost. "Experiment on the oxidation of hydrazine by hydrogen peroxide catalyzed by copper sulfate" (Zhou Lianhong, Sun Xingqi, Ma Xiuling, Jiang He (Shandong Nuclear Power Co., Ltd., Yantai, Shandong 265116) Article No.: 1004-7050 (2015) 02-0080-02) Although the literature discloses Cu 2+It is the only self-oxidation catalyst that has a significant catalytic effect on hydrazine. Experiments have demonstrated that the use of copper sulfate as a catalyst and hydrogen peroxide solution as an oxidant can effectively degrade hydrazine in water. However, when using this method to treat hydrazine in hydrazine-containing wastewater, a large amount of copper ions needs to be added, and a large amount of hydrogen peroxide is also consumed, which increases the treatment cost of hydrazine-containing wastewater. Therefore, it is urgent to develop a more economical and reasonable method for treating hydrazine-containing wastewater to reduce the production burden of enterprises.

[0004] The invention provides a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater, so as to solve the problems of the existing method for treating hydrazine-containing wastewater in the prior art, such as long treatment cycle, low efficiency, poor applicability, high cost of the catalyst used and the need to add a large amount of oxidant to cause treatment cost. Summary of the invention

[0005] The purpose of the present invention is to provide a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater, so as to solve the problems of the existing method for treating hydrazine-containing wastewater in the prior art, such as long treatment cycle, low efficiency, poor applicability, high cost of the catalyst used and the need to add a large amount of additional oxidant, which leads to treatment cost.

[0006] The technical solution of the present invention is: a catalyst for treating hydrazine-containing wastewater, comprising a composite catalyst;

[0007] The composite catalyst contains Cu 2+ , while containing Fe 2+ 、Al 3+ , Mn 2+ An aqueous solution of any one or more metal cations;

[0008] The composite catalyst is prepared by using any one or more of ferrous salt, aluminum salt, divalent manganese salt, copper salt as raw materials and pure water as solution;

[0009] Calculated by mass percentage, the composite catalyst includes 0%-10% of ferrous salt, 2%-15% of copper salt, 1%-10% of aluminum salt, 0%-10% of divalent manganese salt, and 55%-97% of water.

[0010] Preferably, the ferrous salt is selected from any one or more of ferrous sulfate, ferrous chloride, ferrous carbonate, and ammonium ferrous sulfate; and / or,

[0011] The copper salt is selected from any one or more of copper sulfate, copper nitrate, copper chloride and copper carbonate; and / or,

[0012] The aluminum salt is selected from any one or more of aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum silicate, and aluminum sulfide; and / or,

[0013] The divalent manganese salt is selected from any one or more of manganese sulfate, manganese carbonate and manganese dichloride.

[0014] The present invention also provides a method for treating hydrazine-containing wastewater, the method using the above catalyst, and the reaction device used in treating the hydrazine-containing wastewater by the method includes a reaction tank, a catalyst storage tank, a water inlet pump, a pipeline mixer, and a reflux device;

[0015] The input end of the water inlet pump is connected to the device for storing hydrazine-containing wastewater through a water flow pipeline, and the output end is connected to the pipeline mixer through a water flow pipeline. The catalyst storage tank is connected to the pipeline mixer through a catalyst delivery pipeline, and is used to deliver the catalyst and hydrazine-containing wastewater to the pipeline mixer and mix them in the pipeline mixer; the output end of the pipeline mixer is connected to the reaction tank;

[0016] The reflux device comprises a reflux pump; the input end of the reflux pump is connected to the upper part of the reaction tank, and the output end is connected to the bottom of the reaction tank, and is used to reflux the liquid in the upper part of the reaction tank to the bottom of the reaction tank;

[0017] The catalyst delivery pipeline, the water flow pipeline between the water inlet pump and the pipeline mixer are all provided with a flow control valve and a flow detector;

[0018] An air distribution device is provided in the reaction pool; the air distribution device is connected to the compression fan through an air flow pipeline and is used to transport air into the reaction pool;

[0019] A water distribution device is provided at the bottom of the reaction tank; the water distribution device is connected to the output end of the pipeline mixer through a pipeline;

[0020] The processing method comprises the following steps:

[0021] S1. Put the above catalyst into the catalyst storage tank, then start the water inlet pump, and at the same time open the valve on the catalyst delivery pipeline to deliver the hydrazine-containing wastewater and the catalyst to the pipeline mixer;

[0022] S2. Adjust the flow control valve and observe the flow value displayed by the flow detector, so that the hydrazine-containing wastewater and the catalyst are transported to the pipeline mixer at a certain flow ratio and mixed in the pipeline mixer;

[0023] S3, transporting the mixed solution of hydrazine-containing wastewater and catalyst in the pipeline mixer to the reaction tank, and at the same time starting the compression fan to transport the oxidant into the reaction tank, so that a catalytic oxidation reaction occurs in the reaction tank;

[0024] S4. When the water level in the reaction tank rises to the upper part of the reaction tank, the reflux pump is turned on to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation so that the oxidant and the hydrazine-containing wastewater in the reaction tank are mixed more evenly; after the hydrazine-containing wastewater in the reaction tank reacts with the oxidant for 10-48 hours, the reaction is stopped.

[0025] Preferably, in step S2, the flow ratio of the hydrazine-containing wastewater to the catalyst is 1000:(0-5);

[0026] In the step S4, when the liquid inside the reaction tank refluxes, the reflux ratio is 5%-50%.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] (1) The present invention provides a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater. The raw materials of the catalyst are easier to obtain and the preparation method is simpler, so that the cost of the catalyst is lower than that of the commonly used precious metal catalysts; and the catalyst has higher stability and better effect. The reaction device used for treating hydrazine-containing wastewater is equipped with a reflux device, which can not only improve the mixing effect of the oxidant and the hydrazine-containing wastewater, promote the reaction of the oxidant with hydrazine in the hydrazine-containing wastewater, and improve the efficiency of treating hydrazine-containing wastewater, but also make full use of the unreacted catalyst in the upper layer of the reaction tank to carry out The dosage of the catalyst is reduced, and the treatment cost of hydrazine-containing wastewater is saved; the treatment method adopts the above-mentioned catalyst to treat hydrazine-containing wastewater, and its treatment cycle is short and the cost of the catalyst used is low; at the same time, only air is used as an oxidant, so that the treatment method has excellent treatment efficiency and treatment effect, and no additional oxidant is required, which can effectively reduce the treatment cost of hydrazine-containing wastewater; and no secondary pollution is generated; the existing method for treating hydrazine-containing wastewater in the prior art solves the problems of long treatment cycle, low efficiency, poor applicability, high cost of the catalyst used, and treatment cost.

[0029] (2) The present invention provides a catalyst for treating hydrazine-containing wastewater and a method for treating hydrazine-containing wastewater. The reaction device used for treating hydrazine-containing wastewater is equipped with a water distribution device. The water distribution device adopts a multi-point water distribution method, which can make the mixed solution of hydrazine-containing wastewater and catalyst transported to the reaction tank evenly distributed at the bottom of the reaction tank, so that the contact between the hydrazine-containing wastewater in the reaction tank and the air is more sufficient, thereby promoting the catalytic oxidation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0031] Figure 1 It is a structural schematic diagram of the reaction device of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the reaction device of the present invention;

[0033] Among them: 1. Catalyst storage tank; 11. Catalyst delivery pipeline; 2. Water inlet pump; 3. Air distribution device; 31. Compressor fan; 4. Reaction tank; 5. Oxidant distributor; 51. Oxidant delivery pump; 52. Delivery pipeline; 6. Pipeline mixer; 7. Reflux pump; 8. Water distribution device; 9. Flow control valve; 10. Flow detector. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with specific embodiments:

[0035] A catalyst for treating hydrazine-containing wastewater, the catalyst comprising a simple catalyst formed by a single metal cation and a composite catalyst formed by a combination of multiple metal cations. 2+ The composite catalyst is an aqueous solution containing Cu 2+ , while containing Fe 2+ 、Al 3+ , Mn 2+ , Pd 2+ , Rh 3+ Cr 3+ 、Ni 2+ Any one or more aqueous solutions of metal cations such as . Among them, the main catalytic effect in the composite catalyst is Cu 2+ , and the remaining metal ions play a synergistic role. These metal ions have specific catalytic effects in chemical reactions, can provide different catalytic active centers, and at the same time adjust the pH of the reaction system, which helps the reaction rate and thus improves the reaction efficiency.

[0036] The composite catalyst is prepared by dissolving the salt containing the metal cations in a certain ratio in an aqueous solution, namely, copper salt, ferrous salt, aluminum salt, divalent manganese salt, Pd 2+ It is prepared by using one or more of chloride or nitrate, trivalent chromium salt, divalent nickel salt, etc. as raw materials and dissolving them in pure water.

[0037] Due to the presence of Pd 2+ The stability of chlorides or nitrates is poor, which greatly affects their chemical properties, makes them easily ineffective, and is expensive; the stability of trivalent chromium salts is greatly affected by the environment and has certain toxicity; rhodium trichloride is also toxic; nickel salts, including divalent nickel salts, have been identified as carcinogenic; and these metal cations are difficult to remove; therefore, when using composite catalysts to treat hydrazine-containing wastewater, in order to avoid secondary pollution caused by various metal cations contained in the catalyst, Cu-containing 2+ , Fe2+ , Mn 2+ Metal salts such as these are used as raw materials to prepare composite catalysts.

[0038] Calculated by mass percentage, the composite catalyst includes 0%-10% of ferrous salt, 2%-15% of copper salt, 1%-10% of aluminum salt, 0%-10% of divalent manganese salt and the rest of pure water, i.e., 55%-97% of pure water. Among them, the ferrous salt is selected from any one or a combination of ferrous sulfate, ferrous chloride, ferrous carbonate, ammonium ferrous sulfate, etc. that are soluble in water; the copper salt is selected from any one or a combination of copper sulfate, copper nitrate, copper chloride, copper carbonate, etc. that are soluble in water; the aluminum salt is selected from any one or a combination of aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum silicate, aluminum sulfide, etc. that are soluble in water; and the divalent manganese salt is selected from any one or a combination of manganese sulfate, manganese carbonate, manganese dichloride, etc. that are soluble in water.

[0039] The preparation of the composite catalyst includes the following steps: first, pure water is weighed according to a certain mass percentage, and the pure water is put into a reaction container provided with a stirring device; second, one or more of copper salt, ferrous salt, aluminum salt and divalent manganese salt are weighed according to mass percentage respectively, and are added into the above reaction container in sequence, and the stirring device is turned on at the same time, and stirring is performed while adding; after the addition is completed, the mixing and stirring is continued for 30-60 minutes to form the composite catalyst; wherein the mixing and stirring speed is 150-300r / min.

[0040] A reaction device for treating hydrazine-containing wastewater, the reaction device comprises a reaction tank 4, a catalyst storage tank 1 for containing the above-mentioned catalyst, a water inlet pump 2 and a pipeline mixer 6; wherein the input end of the water inlet pump 2 is connected to a device for storing hydrazine-containing wastewater through a water flow pipeline, and the output end is connected to the pipeline mixer 6 through a water flow pipeline, and is used to transport the hydrazine-containing wastewater to the pipeline mixer 6; the catalyst storage tank 1 is connected to the pipeline mixer 6 through a catalyst delivery pipeline 11, and is used to transport the catalyst to the pipeline mixer 6 and mix it with the hydrazine-containing wastewater in the pipeline mixer 6; the output end of the pipeline mixer 6 is connected to the reaction tank 4 through a water flow pipeline, and the mixed catalyst and hydrazine-containing wastewater are transported to the reaction tank. The catalyst delivery pipeline 11 for connecting the catalyst storage tank 1 and the pipeline mixer 6 and the water flow pipeline for connecting the water inlet pump 2 and the pipeline mixer 6 are respectively provided with a flow control valve 9 and a flow detector 10, which are used to adjust the flow of the catalyst and the hydrazine-containing wastewater, and control the flow ratio of the catalyst and the hydrazine-containing wastewater transported to the pipeline mixer 6.

[0041] The reaction device also includes a reflux device; wherein the reflux device includes a reflux pump 7, the input end of the reflux pump 7 is connected to the upper part of the reaction tank 4, and the output end is connected to the bottom of the reaction tank 4. The reflux pump 7 extracts the treated liquid in the upper part of the reaction tank 4 and refluxes it to the bottom of the reaction tank 4 for multiple circulation treatment. The reflux ratio of the liquid in the reaction tank 4 is 5%-50%. The reflux device can not only effectively improve the mixing effect of air and wastewater, but also reuse the unreacted composite catalyst in the upper liquid in the reaction tank 4, improve the utilization rate of the catalyst, and reduce the dosage of the catalyst.

[0042] A water distribution pipe 8 is provided at the bottom of the reaction tank 4; the water distribution pipe 8 is connected to the output end of the pipeline mixer 6 through a water flow pipe, and is used to evenly distribute the catalyst and hydrazine-containing wastewater mixed solution transported to the reaction tank 4 in the reaction tank.

[0043] When the oxidant used is in gaseous state, such as air, a gas distribution device 3 may be provided in the reaction pool 4; Figure 1 As shown, the air distribution device 3 is connected to the compressed air blower 31 through the air flow pipeline, and is used to transport air into the reaction tank 4. The air distribution device 7 in the reaction tank 4 is a micro-nano aerator; the bubbles released by the micro-nano aerator are smaller, which can improve the dissolution efficiency of air in water, thereby increasing the efficiency of the reaction contact. Similarly, when the oxidant used is in liquid form, such as hydrogen peroxide, an oxidant distributor 5 can be set in the reaction tank 4, such as Figure 2 As shown, the oxidant distributor 5 is connected to the output end of the oxidant delivery pump 51 through the delivery pipe 52; the input end of the oxidant delivery pump 51 is connected to the oxidant storage device for delivering the oxidant to the reaction tank; at this time, a flow control valve 9 and a flow detector 10 can be set on the delivery pipe 52; they are used to monitor the flow of the oxidant, which is beneficial to adjust the flow ratio of the oxidant to the hydrazine-containing wastewater.

[0044] When the above-mentioned catalyst and the above-mentioned reaction device are used to treat hydrazine-containing wastewater, the catalyst needs to be placed in a catalyst storage tank first, then the water inlet pump is started, and the valve on the catalyst delivery pipeline is opened at the same time to deliver the hydrazine-containing wastewater and the catalyst to the pipeline mixer; then, the flow value displayed by the flow detector is observed, and the flow control valve is adjusted so that the hydrazine-containing wastewater and the catalyst are delivered to the pipeline mixer at a certain flow ratio and mixed in the pipeline mixer; secondly, the mixed solution of the hydrazine-containing wastewater and the catalyst in the pipeline mixer is delivered to the reaction tank, and the compression fan or the oxidant delivery pump is started at the same time to deliver the oxidant to the reaction tank, so that a catalytic oxidation reaction occurs in the reaction tank; after the water level in the reaction tank rises to the upper part of the reaction tank, the reflux pump is turned on to reflux the liquid in the upper part of the reaction tank to the bottom of the reaction tank, and a reciprocating circulation treatment is performed to make the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly, and finally, the hydrazine-containing wastewater and the oxidant in the reaction tank are reacted under the action of the catalyst for 10-48 hours, and then the reaction is stopped.

[0045] Under the action of the catalyst, the hydrazine in the hydrazine-containing wastewater will react with the oxidant to generate nitrogen and water. The reaction formula is as follows:

[0046] .

[0047] Wastewater discharged from one of the production units of a chemical plant was randomly selected as the hydrazine-containing wastewater to be treated, and multiple groups of experiments were conducted to verify the effect of treating hydrazine-containing wastewater when different oxidants were selected under the same catalyst or without adding catalyst; or, under the same oxidant conditions, the effect of treating hydrazine-containing wastewater with catalysts of different formulations, etc. The hydrazine-containing wastewater to be treated is basically colorless, but has a pungent odor; Table 1 shows some water quality indicators of the wastewater discharged from the production unit.

[0048] Table 1 Some water quality indicators of wastewater

[0049]

[0050] Example 1

[0051] Start the water inlet pump to transport the hydrazine-containing wastewater to the pipeline mixer; then transport the hydrazine-containing wastewater solution in the pipeline mixer to the reaction tank, and start the compression fan to transport air into the reaction tank to cause a catalytic oxidation reaction in the reaction tank; when the water level in the reaction tank rises to a certain height, start the reflux pump to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly; the hydrazine-containing wastewater in the reaction tank is continuously reacted with the oxidant for 24 hours, and then the reaction is stopped. Take an appropriate amount of water in the reaction tank for testing, and calculate the removal rate of the N2H4 removal rate. Example 2

[0052] Start the water inlet pump to deliver the hydrazine-containing wastewater to the pipeline mixer; then deliver the hydrazine-containing wastewater solution in the pipeline mixer to the reaction tank, and start the oxidant delivery pump to deliver 30% H2O2 solution to the reaction tank to cause catalytic oxidation reaction in the reaction tank; and adjust the flow control valve to make the flow ratio of hydrogen peroxide to hydrazine-containing wastewater 1:50; when the water level in the reaction tank rises to a certain height, start the reflux pump to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the oxidant in the reaction tank and the hydrazine-containing wastewater are mixed more evenly; the hydrazine-containing wastewater in the reaction tank and the oxidant react continuously for 24 hours, and then stop the reaction. Take an appropriate amount of water in the reaction tank for detection, and calculate the removal rate of N2H4 removal rate. Example 3

[0053] Start the water inlet pump to deliver the hydrazine-containing wastewater to the pipeline mixer; then deliver the hydrazine-containing wastewater solution in the pipeline mixer to the reaction tank, and start the oxidant delivery pump to deliver sodium hypochlorite solution to the reaction tank to cause catalytic oxidation reaction in the reaction tank; and adjust the flow control valve to make the flow ratio of sodium hypochlorite to hydrazine-containing wastewater 18.6:1000; when the water level in the reaction tank rises to a certain height, start the reflux pump to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the oxidant in the reaction tank and the hydrazine-containing wastewater are mixed more evenly; the hydrazine-containing wastewater in the reaction tank and the oxidant are reacted continuously for 24 hours, and then the reaction is stopped. Take an appropriate amount of water in the reaction tank for detection, and calculate the removal rate of N2H4 removal rate.

[0054] Examples 1-3 use different oxidants to treat hydrazine-containing wastewater, and no catalyst is added during the treatment process. The treatment results are shown in Table 2.

[0055] Table 2 Comparison of the effects of treating hydrazine-containing wastewater in Examples 1-3

[0056]

[0057] As can be seen from Table 2, without adding a catalyst, Examples 1-3 respectively select air, 30% H2O2 solution, and sodium hypochlorite solution as oxidants. The removal rates of hydrazine in the hydrazine-containing wastewater in Example 1 and Example 2 are comparable, and the removal rates are very low, which further indicates that the use of air as an oxidant is similar to the use of 30% H2O2 solution as an oxidant, and the ability and efficiency of treating hydrazine in hydrazine-containing wastewater are comparable; although the removal rate of hydrazine in the hydrazine-containing wastewater in Example 3 is significantly higher than that in the hydrazine-containing wastewater in Examples 1 and 2, its removal rate is only 14.06%; therefore, when the method in Examples 1-3 is used to treat hydrazine-containing wastewater, the reaction efficiency is relatively low. If you want to achieve a removal rate of more than 80%, you need to not only extend the reaction time, but also increase the amount of oxidant added.

[0058] Example 4

[0059] Weigh 99g of pure water and put it into a reaction vessel equipped with a stirring device; weigh 1g of copper sulfate (CuSO4) and add it to the above reaction vessel, turn on the stirring device at the same time, and stir while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a simple catalyst, P4.

[0060] Put the simple catalyst P4 into the catalyst storage tank, then start the water inlet pump, and at the same time open the valve on the catalyst delivery pipeline to deliver the hydrazine-containing wastewater and the composite catalyst P4 to the pipeline mixer; then, observe the flow value displayed by the flow detector, and adjust the flow control valve to deliver the hydrazine-containing wastewater and the catalyst to the pipeline mixer at a flow ratio of 1000:0.5, and mix them in the pipeline mixer; deliver the mixed solution of the hydrazine-containing wastewater and the catalyst in the pipeline mixer to the reaction tank, and at the same time start the compression fan to deliver air into the reaction tank to cause a catalytic oxidation reaction in the reaction tank; when the water level in the reaction tank rises to a certain height, turn on the reflux pump to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly; finally, the hydrazine-containing wastewater and the oxidant in the reaction tank are reacted under the action of the catalyst for 24 hours, and then the reaction is stopped. Take an appropriate amount of water in the reaction tank for detection, and calculate the removal rate of the N2H4 removal rate.

[0061] Example 5

[0062] Weigh 95g of pure water and put it into a reaction vessel equipped with a stirring device; weigh 5g of copper sulfate and add it to the above reaction vessel, turn on the stirring device at the same time, and stir while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a simple catalyst, P5.

[0063] The simple catalyst P5 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 4; after the reaction was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal rate was calculated.

[0064] Example 6

[0065] Weigh 98g of pure water and put it into a reaction container equipped with a stirring device; secondly, weigh 1g of copper sulfate and 3g of ferrous salt respectively, and add them to the above reaction container in turn, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P6.

[0066] The composite catalyst P6 is placed in the catalyst storage tank, and then the water inlet pump is started, and the valve on the catalyst delivery pipeline is opened at the same time, and the hydrazine-containing wastewater and the composite catalyst P6 are delivered to the pipeline mixer; then, the flow value displayed by the flow detector is observed, and the flow control valve is adjusted to deliver the hydrazine-containing wastewater and the catalyst to the pipeline mixer at a flow ratio of 1000:0.5, and mixed in the pipeline mixer; the mixed solution of the hydrazine-containing wastewater and the catalyst in the pipeline mixer is delivered to the reaction tank, and the compression fan is turned on at the same time to deliver air into the reaction tank, so that a catalytic oxidation reaction occurs in the reaction tank; when the water level in the reaction tank rises to a certain height, the reflux pump is turned on to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly; finally, the hydrazine-containing wastewater and the oxidant in the reaction tank are reacted under the action of the catalyst for 24 hours, and then the reaction is stopped. Take an appropriate amount of water in the reaction tank for detection, and calculate the removal rate of the N2H4 removal rate.

[0067] Example 7

[0068] Weigh 92g of pure water and put it into a reaction vessel equipped with a stirring device; secondly, weigh 1g of copper sulfate, 5g of ferrous sulfate (FeSO4), 1g of aluminum chloride (AlCl3) and 1g of manganese sulfate (MnSO4) respectively, and add them to the above reaction vessel in turn, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P7.

[0069] The composite catalyst P7 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 6; after the treatment was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal rate was calculated.

[0070] Example 8

[0071] Weigh 85g of pure water and put it into a reaction container equipped with a stirring device; secondly, weigh 2g of copper sulfate, 8g of ferrous sulfate, 2g of aluminum chloride and 3g of manganese sulfate respectively, and add them to the above reaction container in sequence, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P8.

[0072] The composite catalyst P8 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 6; after the treatment was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal rate was calculated.

[0073] Example 9

[0074] Weigh 79g of pure water and put it into a reaction vessel equipped with a stirring device; secondly, weigh 5g of copper sulfate, 8g of ferrous sulfate, 3g of aluminum chloride and 5g of manganese sulfate respectively, and add them to the above reaction vessel in turn, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P9.

[0075] The composite catalyst P9 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 6; after the treatment was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal rate was calculated.

[0076] Example 10

[0077] Weigh 67g of pure water and put it into a reaction container equipped with a stirring device; secondly, weigh 10g of copper sulfate, 10g of ferrous sulfate, 3g of aluminum chloride and 10g of manganese sulfate respectively, and add them to the above reaction container in sequence, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P10.

[0078] The composite catalyst P10 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 6; after the treatment was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal rate was calculated.

[0079] Embodiment 11

[0080] Weigh 75g of pure water and put it into a reaction container equipped with a stirring device; secondly, weigh 10g of copper sulfate, 5g of aluminum chloride and 10g of manganese sulfate respectively, and add them to the above reaction container in sequence, while turning on the stirring device and stirring while adding; after the addition is completed, continue mixing and stirring for 30 minutes to form a composite catalyst, P11.

[0081] The composite catalyst P11 was placed in a catalyst storage tank, and the hydrazine-containing wastewater was treated by the same treatment method as in Example 6; after the treatment was completed, an appropriate amount of water in the reaction tank was taken for testing, and the removal rate of N2H4 removal was calculated.

[0082] Examples 4-11 all use air as an oxidant, adopt catalysts of different formulations, and use the above-mentioned reaction device to treat hydrazine-containing wastewater; the treatment results are shown in Table 3.

[0083] Table 3 Comparison of the effects of treating hydrazine-containing wastewater in Examples 4-11

[0084]

[0085] As shown in Table 3, compared with Example 1, in Example 4 and Example 5, the addition of a simple catalyst under the condition of air as an oxidant can significantly improve the removal rate and removal efficiency of hydrazine in hydrazine-containing wastewater, and as the Cu in the catalyst increases, the removal rate of hydrazine in the wastewater increases. 2+ As the content increases, the removal rate will increase accordingly; it can be seen that adding a simple catalyst can significantly improve the removal rate of hydrazine in hydrazine-containing wastewater; increasing the amount of catalyst or increasing the Cu content in the catalyst 2+ When treating hydrazine-containing wastewater, the removal rate and removal efficiency of hydrazine in hydrazine-containing wastewater will be further improved. Compared with Examples 1 and 4-5, it can be seen that when adding Fe 2+ 、Al 3+ , Mn 2+ One or more of the above plasmas are used to prepare a composite catalyst for treating hydrazine in hydrazine-containing wastewater, and the removal rate is significantly better than that when a simple catalyst is added or no catalyst is added; furthermore, it is shown that the composite catalyst is used as a catalyst for treating hydrazine in hydrazine-containing wastewater, and its treatment effect and treatment efficiency are more excellent; and with the addition of Cu in the composite catalyst, the removal rate of hydrazine in the wastewater is significantly better than that when a simple catalyst is added or no catalyst is added. 2+ and / or Fe 2+ 、Al 3+ , Mn 2+ As the content increases, the removal rate and removal efficiency increase accordingly; similarly, using the same formula of composite catalyst and increasing the amount of catalyst added can also improve the removal rate and removal efficiency of hydrazine in hydrazine-containing wastewater. A large number of experimental studies have shown that in the process of treating hydrazine-containing wastewater, using 30% H2O2 solution as an oxidant and adding the above composite catalyst can also achieve better treatment effects and higher treatment efficiency. However, from the perspective of cost saving, air is preferred as an oxidant.

[0086] Since hydrazine-containing wastewater contains SO4 2-In order to avoid excessive introduction of other types of anions due to the addition of catalyst, the composite catalyst used in Examples 6-11 preferably contains SO4 2- The metal salt is prepared as the starting material; for example, copper sulfate, ferrous sulfate and manganese sulfate are selected as raw materials in Examples 7-10 to prepare the composite catalyst. The dosage of the catalyst can be determined according to actual needs. The dosage of the catalyst per liter of hydrazine-containing wastewater cannot be less than 0.1mL; and the addition ratio of the catalyst is preferably 0.1~5ml / L. In addition, in order to ensure that the composite catalyst has a high catalytic effect, the content of copper salt in the composite catalyst is preferably 2%-10%, the content of ferrous salt is preferably 5%-10%, the content of aluminum salt is preferably 1%-5%, and the content of divalent manganese salt is preferably 1%-10%.

[0087] Example 12

[0088] In this embodiment, the composite catalyst in the above-mentioned embodiment 10 is selected as P10; the composite catalyst P10 is placed in a catalyst storage tank, and then the water inlet pump is started, and the valve on the catalyst delivery pipeline is opened at the same time, and the hydrazine-containing wastewater and the composite catalyst P10 are delivered to the pipeline mixer; then, the flow value displayed by the flow detector is observed, and the flow control valve is adjusted to make the hydrazine-containing wastewater and the catalyst delivered to the pipeline mixer at a flow ratio of 1000:0.78, and mixed in the pipeline mixer; the mixed solution of the hydrazine-containing wastewater and the catalyst in the pipeline mixer is delivered to In the reaction pool, the oxidant delivery pump is turned on at the same time to deliver 30% H2O2 solution into the reaction pool, so that a catalytic oxidation reaction occurs in the reaction pool, and the flow control valve on the delivery pipeline is adjusted to make the flow ratio of the catalyst to the hydrazine-containing wastewater 25:1000; when the water level in the reaction pool rises to a certain height, the reflux pump is turned on to return the liquid in the upper part of the reaction pool to the bottom of the reaction pool for reciprocating circulation treatment, so that the air in the reaction pool and the hydrazine-containing wastewater are mixed more evenly. The hydrazine-containing wastewater and oxidant in the reaction pool react continuously for 24 hours under the action of the catalyst, and then the reaction is stopped. Take an appropriate amount of water in the reaction pool for detection, and calculate the removal rate of N2H4 removal rate.

[0089] Embodiment 13

[0090] In this embodiment, a purchased palladium nitrate solution Pd15% (15g / 100g liquid) is selected as the catalyst P13; the catalyst P13 is placed in a catalyst storage tank, and then the water inlet pump is started, and the valve on the catalyst delivery pipeline is opened at the same time, and the hydrazine-containing wastewater and the composite catalyst P6 are delivered to the pipeline mixer; then, the flow value displayed by the flow detector is observed, and the flow control valve is adjusted to allow the hydrazine-containing wastewater and the catalyst to be delivered to the pipeline mixer at a flow ratio of 500:1, and mixed in the pipeline mixer; the mixture of the hydrazine-containing wastewater and the catalyst in the pipeline mixer is stirred for 1 h; and the mixture of the hydrazine-containing wastewater and the catalyst in the pipeline mixer is stirred for 1 h. The combined solution is transported to the reaction tank, and the oxidant delivery pump is turned on to deliver 30% H2O2 solution to the reaction tank, so that a catalytic oxidation reaction occurs in the reaction tank. The flow control valve on the delivery pipeline is adjusted to make the flow ratio of the catalyst to the hydrazine-containing wastewater 25:1000; when the water level in the reaction tank rises to a certain height, the reflux pump is turned on to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly. The hydrazine-containing wastewater and oxidant in the reaction tank react continuously for 24 hours under the action of the catalyst, and then the reaction is stopped. Take an appropriate amount of water in the reaction tank for detection, and calculate the removal rate of N2H4 removal rate.

[0091] Embodiment 14

[0092] In this embodiment, a purchased copper-based catalyst (ZnO-CuO-Al2O3) is selected as catalyst P14; the composite catalyst P14 is placed in a catalyst storage tank, and then the water inlet pump is started to transport the hydrazine-containing wastewater to the pipeline mixer; the hydrazine-containing wastewater in the pipeline mixer is then transported to the reaction tank; the catalyst P14 is added to the reaction tank, and the ratio of the amount of the catalyst added to the hydrazine-containing wastewater in the reaction tank is 200g:1L; at the same time, the oxidant delivery pump is started to transport 30% H2O2 solution into the reaction tank to cause a catalytic oxidation reaction in the reaction tank, and the flow control valve on the delivery pipeline is adjusted to make the flow ratio of the catalyst to the hydrazine-containing wastewater 25:1000; when the water level in the reaction tank rises to a certain height, the reflux pump is turned on to reflux the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation treatment, so that the air in the reaction tank and the hydrazine-containing wastewater are mixed more evenly. The hydrazine-containing wastewater and the oxidant in the reaction tank are reacted under the action of the catalyst for 24 hours, and then the reaction is stopped. Take an appropriate amount of water from the reaction tank for testing and calculate the removal rate of N2H4 removal.

[0093] Examples 12-14 all used 30% H2O2 solution as an oxidant, and used the composite catalyst independently developed by the present invention and liquid catalysts and solid catalysts available on the market to treat hydrazine-containing wastewater; the treatment results are shown in Table 4.

[0094] Table 4 Comparison of the effects of treating hydrazine-containing wastewater in Examples 12-14

[0095]

[0096] As can be seen from Table 4, compared with Examples 13-14, Example 12 uses the composite catalyst P10 to treat hydrazine-containing wastewater, and the removal rate of hydrazine in the hydrazine-containing wastewater is significantly better than the removal rate of hydrazine when the purchased palladium nitrate solution Pd15% and the copper-based catalyst are used as catalysts to treat the hydrazine-containing wastewater in Example 13 and Example 14. This further indicates that when the independently developed composite catalyst is added, the catalytic oxidation reaction efficiency is the fastest, the hydrazine removal rate in the hydrazine-containing wastewater is higher, the treatment effect is better, and the amount of catalyst required to be added is less, which can effectively save the treatment cost.

[0097] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A catalyst for treating hydrazine-containing wastewater, characterized in that: including composite catalysts; The composite catalyst comprises Cu 2+ , while containing Fe 2+ 、Al 3+ , Mn 2+ Aqueous solution of The composite catalyst is prepared by using ferrous salt, aluminum salt, divalent manganese salt and copper salt as raw materials and pure water as solution; Calculated by mass percentage, the composite catalyst includes 5%-10% of ferrous salt, 2%-10% of copper salt, 1%-5% of aluminum salt, 1%-10% of divalent manganese salt, and 65%-91% of pure water.

2. A catalyst for treating hydrazine-containing wastewater according to claim 1, characterized in that: The ferrous salt is selected from any one or more of ferrous sulfate, ferrous chloride, and ammonium ferrous sulfate; and / or, The copper salt is selected from any one or more of copper sulfate, copper nitrate and copper chloride; and / or, The aluminum salt is selected from any one or more of aluminum chloride, aluminum sulfate, and aluminum nitrate; and / or, The divalent manganese salt is selected from any one or more of manganese sulfate and manganese dichloride.

3. A method for treating hydrazine-containing wastewater, using the catalyst described in any one of claims 1-2 to treat hydrazine-containing wastewater; and the reaction device used includes a reaction tank, a catalyst storage tank, a water inlet pump, a pipeline mixer and a reflux pump; the input end and the output end of the water inlet pump are respectively connected to the device for storing hydrazine-containing wastewater and the pipeline mixer through a water flow pipeline; The catalyst storage tank is connected to the pipeline mixer through a catalyst delivery pipeline; a flow control valve and a flow detector are provided on the catalyst delivery pipeline, the water flow pipeline between the water inlet pump and the pipeline mixer; The reaction pool is provided with a water distribution device and an air distribution device; the water distribution device is connected to the output end of the pipeline mixer; the air distribution device is connected to the compression fan through the air flow pipeline; The input end of the reflux pump is connected to the upper part of the reaction tank, and the output end is connected to the bottom of the reaction tank; It is characterized in that The treatment method includes the following steps: S1, placing the catalyst into a catalyst storage tank, then starting the water inlet pump, and simultaneously opening the valve on the catalyst delivery pipeline to deliver the hydrazine-containing wastewater and the catalyst to the pipeline mixer; S2. Adjust the flow control valve and observe the flow value displayed by the flow detector, so that the hydrazine-containing wastewater and the catalyst are transported to the pipeline mixer at a certain flow ratio and mixed in the pipeline mixer; S3, transporting the mixed solution of hydrazine-containing wastewater and catalyst in the pipeline mixer to the reaction tank, and at the same time starting the compression fan to transport the oxidant into the reaction tank, so that a catalytic oxidation reaction occurs in the reaction tank; S4. When the water level in the reaction tank rises to the upper part of the reaction tank, the reflux pump is turned on to return the liquid in the upper part of the reaction tank to the bottom of the reaction tank for reciprocating circulation so that the oxidant and the hydrazine-containing wastewater in the reaction tank are mixed more evenly; after the hydrazine-containing wastewater in the reaction tank reacts with the oxidant for 10-48 hours, the reaction is stopped.

4. A method for treating hydrazine-containing wastewater according to claim 3, characterized in that: In the step S2, the flow ratio of the hydrazine-containing wastewater to the catalyst is 1000:(0.5-5); In the step S4, when the liquid inside the reaction tank refluxes, the reflux ratio is 5%-50%.

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