Thallium removal agent for industrial wastewater as well as preparation method and application of thallium removal agent

Abstract

The invention provides an industrial wastewater thallium removal agent as well as a preparation method and application thereof. The thallium removal agent comprises a first reagent and a second reagent, the first reagent comprises the following components in parts by weight: 10-30 parts of sodium sulfide, 20-40 parts of iron oxyhydroxide and 10-50 parts of modified silicon dioxide aerogel; the second reagent comprises the following components in parts by weight: 10-20 parts of polyferric sulfate and 5-10 parts of polyaluminum chloride; the modified silicon dioxide aerogel is prepared by the following method: mixing industrial water glass with water to form a mixed solution, and performing exchange with styrene cation exchange resin to obtain a silicic acid solution with the pH value of 2-3; the preparation method comprises the following steps: dissolving N-acetylcysteine in absolute ethyl alcohol to prepare a modifier; mixing a modifier and a silicic acid solution to form a mixture system, uniformly stirring, and performing aging treatment to obtain wet gel; soaking the wet gel in absolute ethyl alcohol for 10-12 hours, taking out the wet gel, and performing vacuum freeze drying to obtain the modified silicon dioxide aerogel. According to the thallium removal agent disclosed by the invention, the content of thallium ions in wastewater can be reduced to 0.1 ug / L or below, so that the wastewater reaches the environmental quality standard for surface water (GB3838-2002), and the harm of toxic heavy metal thallium to the ecological environment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of niobium and tantalum hydrometallurgical wastewater treatment, and more specifically, relates to an industrial wastewater thallium removal agent and a preparation method and application thereof. Background Art

[0002] The current process for preparing tantalum oxide / niobium oxide from tantalum and niobium is mainly a wet fluoride system, that is, tantalum and niobium ore react with sulfuric acid and hydrofluoric acid, and then undergo pulp extraction, tantalum and niobium separation, and then stripping to produce fluorinated tantalic acid and fluoroniobic acid solutions, and then liquid ammonia or ammonia water is introduced into the fluorotantalic acid and fluoroniobic acid solutions to obtain tantalum hydroxide and niobium oxide, and finally calcined to obtain tantalum oxide and niobium oxide products. Alternatively, hydrofluoric acid is added to fluorotantalic acid to adjust the acidity, and then potassium chloride is added to prepare potassium fluorotantalate products.

[0003] The wastewater from the process of producing tantalum oxide / niobium oxide from tantalum and niobium contains NH4 + 、F - , H + 、SO4 2- In addition to plasma, it also contains a small amount of organic extractant octanol and trace amounts of heavy metal thallium ions. Thallium is a highly toxic heavy metal element. Thallium and its compounds have been included in the monitoring indicator system of my country's surface water environmental quality standards. Therefore, it is necessary to develop an efficient thallium removal agent for the production wastewater of the tantalum-niobium production process of tantalum oxide / niobium oxide. Summary of the invention

[0004] The purpose of the present invention is to provide an industrial wastewater thallium remover and a preparation method and application thereof, so as to efficiently remove thallium from the production wastewater of the tantalum-niobium production process of tantalum oxide / niobium oxide, reduce the harm of the production wastewater to the environment, and make the thallium content in the wastewater reach the safe discharge standard.

[0005] To achieve the above-mentioned object, the first aspect of the present invention provides an industrial wastewater thallium removal agent, comprising a first agent and a second agent;

[0006] The first reagent contains the following components in parts by weight: 10 to 30 parts of sodium sulfide, 20 to 40 parts of iron oxyhydroxide, and 10 to 50 parts of modified silica aerogel;

[0007] The second reagent contains the following components by weight: 10-20 parts of polyferric sulfate and 5-10 parts of polyaluminium chloride;

[0008] The modified silica aerogel is prepared by the following method:

[0009] Industrial water glass is mixed with water to form a mixed solution, and a silicic acid solution with a pH of 2 to 3 is obtained by exchanging with a styrene cation exchange resin;

[0010] Dissolving N-acetylcysteine ​​in anhydrous ethanol to prepare a modifier;

[0011] The modifier and the silicic acid solution are mixed into a mixture system, stirred evenly and then subjected to aging treatment to obtain a wet gel;

[0012] The wet gel is soaked in anhydrous ethanol for 10 to 12 hours, taken out and then vacuum-freeze-dried to obtain a modified silica aerogel.

[0013] Furthermore, in the mixed solution, the volume ratio of industrial water glass to water is 1:3 to 1:5.

[0014] Furthermore, the mass concentration of the modifier is 10-20%.

[0015] Furthermore, in the mixture system, the volume ratio of the modifier to the silicic acid solution is 0.5 to 1:1.

[0016] Furthermore, the aging treatment conditions are: aging at 40-50° C. for 8-10 hours.

[0017] Furthermore, a Pt nanoparticle solution is also added to the mixture system.

[0018] Furthermore, the amount of the Pt nanoparticle solution added to the mixture system is 1-5%.

[0019] The second aspect of the present invention provides a method for preparing an industrial wastewater thallium removal agent, comprising the following steps:

[0020] preparing modified silica aerogel;

[0021] Weighing sodium sulfide, ferric oxyhydroxide, and the modified silica aerogel according to a weight ratio and mixing them to obtain a first reagent;

[0022] Weigh polyferric sulfate and polyaluminium chloride according to a weight ratio and mix them evenly to obtain a second reagent.

[0023] The third aspect of the present invention provides an application of an industrial wastewater thallium removal agent in removing thallium from industrial wastewater, wherein the agent is used according to the following method:

[0024] The first reagent is added with water to prepare a first suspension system with a relative density of 1.4 to 1.9; the second reagent is added with water to prepare a second solution system with a relative density of 1.5 to 2;

[0025] First, the first suspension system is added to the industrial wastewater to be treated, and the mixture is stirred for reaction for 5 to 10 minutes; then, the second solution system is added, and the mixture is stirred for reaction for 5 to 10 minutes, and then allowed to stand.

[0026] Furthermore, the industrial wastewater is wastewater produced by the process of preparing tantalum oxide / niobium oxide from tantalum and niobium, the dosage of the first suspension system is 1 to 2‰ of the weight of the wastewater to be treated, and the dosage of the second solution system is 1.5 to 2‰ of the weight of the wastewater to be treated.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] An industrial wastewater thallium remover of the invention comprises a first reagent and a second reagent, wherein the sodium sulfide in the first reagent can be combined with heavy metal ions such as thallium in the industrial wastewater to form a sulfide precipitate; the iron oxyhydroxide has a large specific surface area and can adsorb and remove heavy metal ions such as thallium in the wastewater; the porous adsorption structure of the modified silica aerogel can also quickly adsorb and remove heavy metal ions such as thallium in the wastewater; in addition, the surface of the three-dimensional mesh structure of the silica aerogel modified by N-acetylcysteine ​​also has more active groups such as -COOH, -NH, -SH, etc., which can provide more active adsorption sites, and in an alkaline water environment, it is more conducive to the combination of heavy metal ions such as thallium in the wastewater with the active adsorption sites of the modified silica aerogel, thereby improving the adsorption and removal capacity of heavy metals such as thallium in the wastewater. The sodium sulfide, ferric oxyhydroxide and modified silica aerogel in the first reagent of the present invention can produce a synergistic effect in removing thallium from wastewater, and the generated thallium-containing precipitate can be quickly adsorbed and deposited on the three-dimensional mesh structure of the modified silica aerogel, preventing thallium ions from returning to the water phase; combined with the rapid flocculation and sedimentation effect of polyferric sulfate and polyaluminium chloride in the second reagent, the thallium ion content in the wastewater can be reduced to below 0.1 ug / L, meeting the "Surface Water Environmental Quality Standard (GB3838-2002)", and reducing the harm of toxic heavy metal thallium to the ecological environment.

[0029] In addition, the iron hydroxide oxide in the industrial wastewater thallium removal agent of the present invention also has an oxidizing effect. Under natural light, it can degrade the organic octanol in the wastewater produced by the process of preparing tantalum oxide / niobium oxide from tantalum and niobium, thereby reducing the pollution of organic matter in the wastewater. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0032] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. For example, without departing from the scope of the embodiments of the present invention, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0033] Example 1

[0034] Embodiment 1 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0035] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 15%; the modifier and the silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0036] (2) Weigh 20 g of sodium sulfide, 20 g of iron oxyhydroxide, and 40 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0037] (3) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0038] Example 2

[0039] Embodiment 2 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0040] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 10%; the modifier and the silica solution are mixed in a volume ratio of 1:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0041] (2) Weigh 20 g of sodium sulfide, 20 g of iron oxyhydroxide, and 40 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0042] (3) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0043] Example 3

[0044] Embodiment 3 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0045] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 20%; the modifier and the silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0046] (2) Weigh 20 g of sodium sulfide, 20 g of iron oxyhydroxide, and 40 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0047] (3) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0048] Example 4

[0049] Embodiment 4 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0050] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 15%; the modifier and the silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0051] (2) Weigh 30 g of sodium sulfide, 20 g of iron oxyhydroxide, and 50 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0052] (3) Weigh 10 g of polyferric sulfate and 10 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0053] Example 5

[0054] Embodiment 5 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0055] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 15%; the modifier and the silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0056] (2) Weigh 10 g of sodium sulfide, 40 g of iron oxyhydroxide, and 20 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0057] (3) Weigh 10 g of polyferric sulfate and 10 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0058] Example 6

[0059] Embodiment 4 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0060] (1) Preparation of modified silica aerogel: industrial water glass with a modulus of 3.0 and water are mixed in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; N-acetylcysteine ​​is dissolved in anhydrous ethanol to prepare a modifier with a mass concentration of 15%; the modifier and the silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, and then a 2wt% Pt nanoparticle solution is added to the mixture system, and the mixture is stirred evenly and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, and then taken out and vacuum freeze-dried for 24 hours to obtain a modified silica aerogel.

[0061] The Pt nanoparticle solution was prepared as follows: 1 mL of 5% PtCl4 solution was added to 100 ml of deionized water, 15 mL of 1% trisodium citrate solution was added under stirring, the mixture was stirred and reacted at 80° C. for 1 h, 0.5 mL of 1% sodium borohydride solution was added, and the mixture was heated under reflux at 80° C. for 0.5 h, and the Pt nanoparticle solution was obtained after cooling.

[0062] (2) Weigh 20 g of sodium sulfide, 20 g of iron oxyhydroxide, and 40 g of modified silica aerogel respectively, and mix them to form a first reagent.

[0063] (3) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0064] Comparative Example 1

[0065] Comparative Example 1 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0066] (1) Preparation of silica aerogel: industrial water glass with a modulus of 3.0 is mixed with water in a volume ratio of 1:4, and exchanged with a styrene cation exchange resin to obtain a silica solution with a pH of 2.6; anhydrous ethanol and a silica solution are mixed in a volume ratio of 0.5:1 to form a mixture system, stirred evenly, and aged at 45°C for 10 hours to obtain a wet gel; the wet gel is placed in an equal volume of anhydrous ethanol and immersed for 10 hours, taken out, and vacuum freeze-dried for 24 hours to obtain a silica aerogel.

[0067] (2) Weigh 20 g of sodium sulfide, 20 g of iron oxyhydroxide, and 40 g of silica aerogel respectively, and mix them to form a first reagent.

[0068] (3) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0069] Comparative Example 2

[0070] Comparative Example 2 of the present invention provides an industrial wastewater thallium removal agent and a preparation method thereof, comprising the following steps:

[0071] (1) Weigh 20 g of sodium sulfide and 60 g of ferric oxyhydroxide respectively and mix them to form the first reagent.

[0072] (2) Weigh 20 g of polyferric sulfate and 5 g of polyaluminium chloride respectively and mix them to form the second reagent.

[0073] The first reagent and the second reagent prepared in Examples 1-6, Comparative Example 1 and Comparative Example 2 of the present invention were each added with water to prepare a first suspension system with a relative density of 1.4-1.9 and a second solution system with a relative density of 1.5-2.

[0074] The wastewater produced by the tantalum oxide / niobium oxide process is used as the industrial wastewater to be treated in the embodiment of the present invention. The content of thallium ions in the industrial wastewater to be treated is 56ug / L, the content of octanol is 170mg / L, and the pH is 9-10. The first suspension system with a relative density of 1.4-1.9 prepared by Examples 1-6, Comparative Example 1, and Comparative Example 2 of the present invention is respectively added to the industrial wastewater to be treated, stirred for 5 minutes, and then the second solution system with a relative density of 1.5-2 is added respectively, stirred for 10 minutes, and then allowed to stand, and the supernatant is taken to detect the thallium ion content and the octanol content. Among them, the dosage of the first suspension system is 1-2‰ of the weight of the wastewater to be treated, and the dosage of the second solution system is 1.5-2‰ of the weight of the wastewater to be treated.

[0075] The contents of thallium ions and 2-octanol in the treated wastewater were tested and the results are shown in the following table.

[0076]

[0077] From the test results in the above table, it can be seen that the thallium removal agents prepared in Examples 1 to 6 of the present invention all show good thallium removal effects on thallium in wastewater. After treatment, the thallium content in the wastewater will be reduced to below 0.1 ug / L, meeting the "Surface Water Environmental Quality Standard (GB3838-2002)", reducing the harm of toxic heavy metal thallium to the ecological environment.

[0078] The comparison between Example 1 and Comparative Example 1 shows that the modified silica aerogel used in the first reagent of the thallium removal agent has a better thallium removal effect than the silica aerogel.

[0079] The comparison between Example 1 and Comparative Example 2 shows that adding modified silica aerogel to the first reagent of the thallium removal agent can significantly improve the thallium removal efficiency of the thallium removal agent.

[0080] Comparison between Example 1 and Example 6 shows that adding Pt nanoparticles to the modified silica aerogel is beneficial to the removal of organic sec-octanol in wastewater, but has little effect on the removal of thallium ions.

[0081] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. An industrial wastewater thallium removal agent, characterized in that: comprising a first reagent and a second reagent; The first reagent contains the following components in parts by weight: 10 to 30 parts of sodium sulfide, 20 to 40 parts of iron oxyhydroxide, and 10 to 50 parts of modified silica aerogel; The second reagent contains the following components by weight: 10-20 parts of polyferric sulfate and 5-10 parts of polyaluminium chloride; The modified silica aerogel is prepared by the following method: Industrial water glass is mixed with water to form a mixed solution, and a silicic acid solution with a pH of 2 to 3 is obtained by exchanging with a styrene cation exchange resin; Dissolving N-acetylcysteine ​​in anhydrous ethanol to prepare a modifier; The modifier and the silicic acid solution are mixed into a mixture system, stirred evenly and then subjected to aging treatment to obtain a wet gel; The wet gel is soaked in anhydrous ethanol for 10 to 12 hours, taken out and then vacuum-freeze-dried to obtain a modified silica aerogel.

2. The thallium removal agent for industrial wastewater according to claim 1, characterized in that: In the mixed solution, the volume ratio of industrial water glass to water is 1:3 to 1:

5.

3. The thallium removal agent for industrial wastewater according to claim 1, characterized in that: The mass concentration of the modifier is 10-20%.

4. The industrial wastewater thallium removal agent according to claim 1, characterized in that: In the mixture system, the volume ratio of the modifier to the silicic acid solution is 0.5 to 1:

1.

5. The thallium removal agent for industrial wastewater according to claim 1, characterized in that: The aging treatment conditions are: aging at 40-50° C. for 8-10 hours.

6. An industrial wastewater thallium removal agent as claimed in any one of claims 1 to 5, characterized in that: A Pt nanoparticle solution is also added into the mixture system.

7. An industrial wastewater thallium removal agent as claimed in claim 6, characterized in that: The amount of the Pt nanoparticle solution added to the mixture system is 1-5%.

8. A method for preparing an industrial wastewater thallium removal agent as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: preparing modified silica aerogel; Weighing sodium sulfide, ferric oxyhydroxide, and the modified silica aerogel according to a weight ratio and mixing them to obtain a first reagent; Weigh polyferric sulfate and polyaluminium chloride according to a weight ratio and mix them evenly to obtain a second reagent.

9. Use of an industrial wastewater thallium removal agent as claimed in any one of claims 1 to 7 in removing thallium from industrial wastewater, characterized in that: Use the medicine as follows: The first reagent is added with water to prepare a first suspension system with a relative density of 1.4 to 1.9; the second reagent is added with water to prepare a second solution system with a relative density of 1.5 to 2; First, add the first suspension system to the industrial wastewater to be treated, and stir to react for 5 to 10 minutes; Then, the second solution system is added, stirred to react for 5 to 10 minutes, and then allowed to stand.

10. The use of an industrial wastewater thallium removal agent as claimed in claim 9 in removing thallium from industrial wastewater, characterized in that: The industrial wastewater is wastewater produced by the process of preparing tantalum oxide / niobium oxide from tantalum and niobium. The dosage of the first suspension system is 1-2‰ of the weight of the wastewater to be treated, and the dosage of the second solution system is 1.5-2‰ of the weight of the wastewater to be treated.

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