A composite thallium removal agent, a preparation method, application and regeneration method thereof

Abstract

This invention belongs to the field of water pollution control technology, and provides a composite thallium removal agent and its preparation, application, and regeneration methods. This invention involves mixing iron oxide and metal hydroxide powders with ammonia water, and through a first reaction, generating hydroxyl-containing iron oxide (Fe₂O₃(OH)₃). x Fe2O3(OH) x The metal in the metal hydroxide and the ammonium ions of ammonia water undergo a second reaction to form Fe-NH-M-OH precipitate; calcining the Fe-NH-M-OH precipitate yields the amino-rich composite oxide NH2-FeMO. x Sodium thiosulfate is adsorbed onto the surface of amino-rich composite oxides, ultimately forming a composite thallium removal agent. The strong adsorption of heavy metal thallium by metal M (from metal hydroxide) and Fe is utilized to achieve effective removal of thallium. Simultaneously, the introduction of amino and sulfur functional groups on the surface of the composite thallium removal agent also enhances its thallium removal efficiency.

Description

Technical Field

[0001] This invention relates to the field of water pollution control technology, and in particular to a composite thallium removal agent and its preparation, application and regeneration methods. Background Technology

[0002] Thallium is a highly hazardous heavy metal, typically existing as a by-product in metallic or non-metallic minerals. During smelting, it is emitted into flue gas, and after flue gas purification, thallium is transferred to wastewater, such as wastewater from lead and zinc smelting. Thallium not only causes environmental pollution but also poses serious threats to human health. To meet environmental protection requirements and wastewater discharge standards, it is necessary to deeply purify and remove the heavy metal thallium from smelting wastewater.

[0003] Currently, methods for removing the heavy metal thallium mainly include oxidation, precipitation, and adsorption. Precipitation has drawbacks such as difficulty in treating thallium-containing sludge and secondary pollution; oxidation has disadvantages such as high operating costs and inability to achieve deep removal. Compared to oxidation and precipitation, adsorption offers higher resistance to wastewater concentration fluctuations, higher deep removal efficiency, better regeneration performance, and less secondary pollution. Chinese patent CN113830850A discloses a deep thallium removal catching agent for smelting wastewater and its preparation method. This method mixes activated carbon powder, iron salt, complexing agent, and flocculant to prepare a thallium catching agent, achieving deep removal of thallium from smelting wastewater. However, it suffers from drawbacks such as difficulty in regenerating the catching agent and high preparation costs. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a composite thallium removal agent, its preparation method, application, and regeneration method. The composite thallium removal agent obtained by the preparation method provided by this invention has a high thallium removal rate and is easy to regenerate.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a composite thallium removal agent, comprising the following steps:

[0007] Iron oxide and metal hydroxide are mixed to obtain a mixed powder;

[0008] The mixed powder is mixed with ammonia water, and the first and second reactions are carried out sequentially to obtain Fe-NH-M-OH precipitate, wherein M in the Fe-NH-M-OH precipitate is a metal in a metal hydroxide.

[0009] The Fe-NH-M-OH precipitate was calcined to obtain a composite oxide rich in amino groups;

[0010] The amino-rich composite oxide, sodium thiosulfate, and water are mixed and subjected to an adsorption reaction to obtain the composite thallium removal agent.

[0011] Preferably, the metal hydroxide includes one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide;

[0012] The mass ratio of the iron oxide to the metal hydroxide is 10:1 to 4.

[0013] Preferably, the ammonia water is saturated ammonia water; the mass ratio of the mixed powder to the ammonia water is 1:1 to 4.

[0014] Preferably, the first reaction is carried out under normal temperature and pressure conditions with stirring; the stirring speed is 200-500 r / min and the time is 30-120 min.

[0015] Preferably, the temperature of the second reaction is 120-200℃ and the pressure is 0.3-0.8MPa; the second reaction is carried out under stirring conditions, the stirring speed is 100-300r / min and the time is 0.5-2h.

[0016] Preferably, the roasting temperature is 300–500°C and the time is 1–4 hours.

[0017] Preferably, the mass ratio of the amino-rich composite oxide to sodium thiosulfate is 10:1 to 5;

[0018] The adsorption reaction is carried out under normal temperature and pressure conditions with stirring. The stirring speed is 100-400 r / min and the time is 10-60 min.

[0019] The present invention also provides a composite thallium removal agent prepared by the preparation method described in the above technical solution.

[0020] The present invention also provides the application of the composite thallium removal agent described in the above technical solution in the treatment of smelting wastewater.

[0021] The present invention also provides a method for regenerating the composite thallium removal agent described in the above technical solution, comprising the following steps:

[0022] The composite thallium removal agent to be regenerated is immersed in ethanol to achieve regeneration of the composite thallium removal agent.

[0023] This invention provides a method for preparing a composite thallium removal agent, comprising the following steps: mixing iron oxide and a metal hydroxide to obtain a mixed powder; mixing the mixed powder with ammonia water and sequentially performing a first reaction and a second reaction to obtain a Fe-NH-M-OH precipitate, wherein M in the Fe-NH-M-OH precipitate is a metal in the metal hydroxide; calcining the Fe-NH-M-OH precipitate to obtain an amino-rich composite oxide; mixing the amino-rich composite oxide, sodium thiosulfate, and water, and performing an adsorption reaction to obtain the composite thallium removal agent.

[0024] This invention involves mixing powdered iron oxide, metal hydroxide, and ammonia water, followed by a first reaction to generate hydroxyl-containing iron oxide (Fe2O3(OH)). x Then, through a second reaction, Fe₂O₃(OH)₃ x The metal in the metal hydroxide reacts with the ammonium ions of ammonia water to form Fe-NH-M-OH precipitate. Calcining the Fe-NH-M-OH precipitate yields the amino-rich complex oxide NH2-FeMO. x Sodium thiosulfate is adsorbed onto the surface of amino-rich composite oxides, ultimately forming a composite thallium removal agent.

[0025] Beneficial effects:

[0026] (1) The strong adsorption of heavy metal thallium by metals M and Fe is used to achieve effective removal of heavy metal thallium.

[0027] (2) The composite thallium removal agent prepared by this invention has abundant surface amino functional groups and sulfo functional groups (derived from thiosulfate groups), exhibiting strong adsorption and capture capabilities for thallium and excellent heavy metal thallium removal effect. The synergistic effect of the surface amino and sulfo functional groups can improve the chemical adsorption efficiency of Fe element, thereby increasing the service life and stability of the composite thallium removal agent. The used thallium removal agent has good regenerability, generates no secondary pollution, and the process is green and environmentally friendly.

[0028] (3) The preparation method provided by the present invention is simple to operate, the preparation time of the composite thallium removal agent is relatively short, the raw materials are cheap and readily available, and it is easy to realize industrial application. The thallium removal efficiency can reach 100%. Attached Figure Description

[0029] Figure 1 The Tl removal efficiency of the thallium removal agent and the regenerated thallium removal agent in Example 1 of the present invention;

[0030] Figure 2 The Tl removal efficiency of the thallium removal agent and the regenerated thallium removal agent in Example 2 of the present invention;

[0031] Figure 3The Tl removal efficiency of the thallium removal agent and the regenerated thallium removal agent in Example 3 of the present invention. Detailed Implementation

[0032] This invention provides a method for preparing a composite thallium removal agent, comprising the following steps:

[0033] Iron oxide and metal hydroxide are mixed to obtain a mixed powder;

[0034] The mixed powder is mixed with ammonia water, and the first and second reactions are carried out sequentially to obtain Fe-NH-M-OH precipitate, wherein M in the Fe-NH-M-OH precipitate is a metal in a metal hydroxide.

[0035] The Fe-NH-M-OH precipitate was calcined to obtain a composite oxide rich in amino groups;

[0036] The amino-rich composite oxide, sodium thiosulfate, and water are mixed and subjected to an adsorption reaction to obtain the composite thallium removal agent.

[0037] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0038] This invention mixes iron oxide and metal hydroxide to obtain a mixed powder.

[0039] In this invention, the metal hydroxide preferably includes one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0040] In this invention, the mass ratio of iron oxide to metal hydroxide is preferably 10:1 to 4, and more preferably 10:2 to 3.

[0041] After obtaining the mixed powder, the present invention mixes the mixed powder with ammonia water and performs the first reaction and the second reaction in sequence to obtain Fe-NH-M-OH precipitate, wherein M in the Fe-NH-M-OH precipitate is a metal in the metal hydroxide.

[0042] In this invention, the ammonia water is preferably saturated ammonia water; the mass ratio of the mixed powder to the ammonia water is preferably 1:1 to 4, and more preferably 1:2 to 3.

[0043] In this invention, the first reaction is preferably carried out under normal temperature and pressure and stirring conditions; the stirring speed is preferably 200-500 r / min, more preferably 300-400 r / min; the time is preferably 30-120 min, more preferably 60-90 min.

[0044] In this invention, during the first reaction, ammonia reacts with iron oxide (Fe2O3) to generate iron oxide (Fe2O3(OH)) with hydroxyl groups.x )precipitation.

[0045] After the first reaction, the present invention proceeds directly to the second reaction without any further action.

[0046] In this invention, the temperature of the second reaction is preferably 120–200°C, more preferably 150–170°C; the pressure is preferably 0.3–0.8 MPa, more preferably 0.4–0.7 MPa, and even more preferably 0.5–0.6 MPa; the second reaction is preferably carried out under stirring conditions, the stirring speed is preferably 100–300 r / min, more preferably 200 r / min; and the time is preferably 0.5–2 h. In this invention, the second reaction is preferably carried out in a high-pressure reactor.

[0047] In this invention, during the second reaction, Fe2O3(OH) x The metal in the metal hydroxide reacts with the ammonium ions of ammonia water to form a Fe-NH-M-OH precipitate.

[0048] After the second reaction, the present invention preferably further includes: cooling the obtained second reaction suspension to room temperature and filtering it to obtain a Fe-NH-M-OH precipitate.

[0049] After obtaining Fe-NH-M-OH precipitate, the present invention calcines the Fe-NH-M-OH precipitate to obtain a composite oxide rich in amino groups.

[0050] In this invention, the roasting temperature is preferably 300–500°C, more preferably 400°C; the roasting time is preferably 1–4 hours. In this invention, the roasting is preferably carried out in a muffle furnace. After roasting, this invention preferably further includes furnace cooling to room temperature.

[0051] After obtaining the amino-rich composite oxide, the present invention mixes the amino-rich composite oxide, sodium thiosulfate and water, and carries out an adsorption reaction to obtain the composite thallium removal agent.

[0052] In this invention, the water is preferably deionized water. In this invention, the mass ratio of the amino-rich complex oxide to sodium thiosulfate is preferably 10:1 to 5.

[0053] In this invention, the adsorption reaction is preferably carried out under normal temperature and pressure and stirring conditions. The stirring speed is preferably 100-400 r / min, more preferably 200-300 r / min; the stirring time is preferably 10-60 min.

[0054] Following the adsorption reaction, the present invention preferably further includes removing water from the resulting adsorption reaction solution to obtain the composite thallium removal agent. In this invention, the method for removing water from the resulting adsorption reaction solution is preferably vacuum drying; the present invention does not specifically limit the parameters of the vacuum drying, as long as the water can be removed.

[0055] In this invention, the adsorption reaction can introduce thiosulfate groups onto the surface of the composite thallium removal agent. These thiosulfate groups can form sulfate ions and S during the thallium removal process. 2- Ions can effectively extend the service life of composite thallium removal agents.

[0056] The present invention also provides a composite thallium removal agent prepared by the preparation method described in the above technical solution. In the present invention, the composite thallium removal agent comprises Fe-M composite oxide, and -NH2 groups and thiosulfate groups on the surface of the Fe-M composite oxide.

[0057] The present invention also provides the application of the composite thallium removal agent described in the above technical solution in the treatment of smelting wastewater.

[0058] In this invention, the application preferably includes the following steps:

[0059] The composite thallium removal agent is mixed with thallium-containing smelting wastewater to remove thallium.

[0060] In this invention, the thallium content in the thallium-containing smelting wastewater is preferably 80–120 mg / L. In this invention, the dosage of the composite thallium removal agent is preferably 1–3 g / L, more preferably 2 g / L. In this invention, the thallium removal is preferably carried out under normal temperature and pressure conditions.

[0061] The present invention also provides a method for regenerating a composite thallium removal agent, comprising the following steps:

[0062] The composite thallium removal agent to be regenerated is immersed in ethanol to achieve regeneration of the composite thallium removal agent.

[0063] In this invention, the impregnation temperature is preferably 20-50°C, and the impregnation is carried out under stirring conditions.

[0064] After the impregnation is completed, the present invention further includes: filtering the obtained suspension to obtain a thallium-containing organic phase and a regenerated composite thallium removal agent.

[0065] In this invention, the thallium-containing organic phase is preferably treated by removing ethanol through evaporation and concentration to achieve the recovery and reuse of thallium.

[0066] The regeneration method provided by this invention is simple to operate.

[0067] The following detailed description, in conjunction with embodiments, illustrates the composite thallium removal agent provided by the present invention, its preparation method, application, and regeneration method. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] Iron oxide and sodium hydroxide were mixed at a mass ratio of 10:3 to form a mixed solid powder A. Mixed solid powder A was dissolved in saturated ammonia water at a mass ratio of 1:4 and stirred at 200 rpm for 90 min at room temperature and pressure to obtain a mixture B. Mixture B was placed in a magnetically stirred high-pressure reactor and stirred at 300 rpm for 2 h at 120 °C and 0.6 MPa. After stirring, it was cooled to room temperature and filtered to obtain solid C. Solid C was placed in a muffle furnace and calcined at 300 °C for 4 h and cooled to room temperature to obtain solid D. Solid D and sodium thiosulfate were dissolved in deionized water at a mass ratio of 10:1 and stirred at 300 rpm for 20 min at room temperature and pressure. The water was then removed by vacuum drying to obtain the composite thallium removal agent.

[0070] The performance test of the composite thallium removal agent was conducted in a magnetically stirred reactor. The reaction conditions were: simulated thallium concentration of 80 mg / L in smelting wastewater, thallium removal agent dosage of 2 g / L, and reaction at room temperature and pressure. The thallium removal rate results are shown in […]. Figure 1 ,from Figure 1 The results show that the thallium removal rate reached 100% after 20 minutes, indicating that the thallium removal agent has a significant effect on the removal of thallium.

[0071] Example 2

[0072] Iron oxide and potassium hydroxide were mixed at a mass ratio of 10:1 to form a mixed solid powder A. Mixed solid powder A was dissolved in saturated ammonia water at a mass ratio of 1:2 and stirred at 400 rpm for 120 min at room temperature and pressure to obtain a mixed solution B. Mixed solution B was placed in a magnetically stirred high-pressure reactor and stirred at 100 rpm for 1 h at 200 °C and 0.8 MPa. After stirring, it was cooled to room temperature and filtered to obtain solid C. Solid C was placed in a muffle furnace and calcined at 400 °C for 2 h and cooled to room temperature to obtain solid D. Solid D and sodium thiosulfate were dissolved in deionized water at a mass ratio of 10:3 and stirred at 100 rpm for 10 min at room temperature and pressure. The water was then removed by vacuum drying to obtain the composite thallium removal agent.

[0073] The performance test of the composite thallium removal agent was conducted in a magnetically stirred reactor. The reaction conditions were: simulated thallium concentration of 80 mg / L in smelting wastewater, thallium removal agent dosage of 2 g / L, and reaction at room temperature and pressure. The thallium removal rate results are shown in […]. Figure 2 ,from Figure 2It can be seen that the thallium removal rate reached 100% after 15 minutes, which indicates that the thallium removal agent has a significant effect on the removal of thallium.

[0074] Example 3

[0075] Iron oxide and calcium hydroxide were mixed at a mass ratio of 10:4 to form a mixed solid powder A. Mixed solid powder A was dissolved in saturated ammonia water at a mass ratio of 1:1 and stirred at 500 rpm for 30 min at room temperature and pressure to obtain a mixture B. Mixture B was placed in a magnetically stirred high-pressure reactor and stirred at 200 rpm for 0.5 h at 170 °C and 0.3 MPa. After stirring, it was cooled to room temperature and filtered to obtain solid C. Solid C was placed in a muffle furnace and calcined at 500 °C for 1 h and then cooled to room temperature to obtain solid D. Solid D and sodium thiosulfate were dissolved in deionized water at a mass ratio of 10:5 and stirred at 400 rpm for 60 min at room temperature and pressure. The water was then removed by vacuum drying to obtain the composite thallium removal agent.

[0076] The performance test of the composite thallium removal agent was conducted in a magnetically stirred reactor. The reaction conditions were: simulated thallium concentration of 80 mg / L in smelting wastewater, thallium removal agent dosage of 2 g / L, and reaction at room temperature and pressure. The thallium removal rate results are shown in […]. Figure 3 ,from Figure 3 It can be seen that the thallium removal rate reached 100% after 30 minutes, which indicates that the thallium removal agent has a significant effect on the removal of thallium.

[0077] The composite thallium removal agent used in Examples 1-3 is regenerated by heating and stirring with anhydrous ethanol (at 30°C). This transfers thallium from the adsorbent to the ethanol phase, which is then separated by filtration, thus regenerating the thallium removal agent. The thallium in the ethanol can be collected by evaporation and concentration for other uses. This regeneration process is simple and solves the problems of treatment, disposal, and regeneration of traditional thallium removal agents.

[0078] The results of thallium removal rate by the regenerated thallium removal agent are shown in [the table below]. Figures 1-3 ,from Figures 1-3 It can be seen that the regenerated thallium removal agent can restore the thallium removal rate to 100%, which indicates that the regeneration method is feasible.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a composite thallium removal agent, characterized in that, Includes the following steps: Iron oxide and metal hydroxide are mixed to obtain a mixed powder; The mixed powder is mixed with ammonia water, and the first and second reactions are carried out sequentially to obtain Fe-NH-M-OH precipitate, wherein M in the Fe-NH-M-OH precipitate is a metal in a metal hydroxide. The Fe-NH-M-OH precipitate was calcined to obtain a composite oxide rich in amino groups; The amino-rich composite oxide, sodium thiosulfate, and water are mixed and subjected to an adsorption reaction to obtain the composite thallium removal agent. The metal hydroxide includes one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide; The first reaction is carried out under normal temperature and pressure with stirring; the stirring speed of the first reaction is 200~500 r / min, and the time is 30~120 min; The temperature of the second reaction is 120~200℃ and the pressure is 0.3~0.8MPa; the second reaction is carried out under stirring conditions, the stirring speed is 100~300r / min and the time is 0.5~2h.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the iron oxide to the metal hydroxide is 10:1~4.

3. The preparation method according to claim 1, characterized in that, The ammonia water is saturated ammonia water; the mass ratio of the mixed powder to the ammonia water is 1:1~4.

4. The preparation method according to claim 1, characterized in that, The roasting temperature is 300~500℃ and the time is 1~4h.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the amino-rich composite oxide to sodium thiosulfate is 10:1~5; The adsorption reaction is carried out under normal temperature and pressure conditions with stirring. The stirring speed is 100~400 r / min and the time is 10~60 min.

6. The composite thallium removal agent prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the composite thallium removal agent according to claim 6 in the treatment of smelting wastewater.

8. A method for regenerating the composite thallium removal agent prepared by the preparation method according to any one of claims 1 to 5, characterized in that, Includes the following steps: The composite thallium removal agent to be regenerated is immersed in ethanol to achieve regeneration of the composite thallium removal agent.

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