Lead removal agent FT236 as well as preparation method and application thereof

Abstract

The invention provides a deleading agent FT236 and a preparation method and application thereof, the deleading agent FT236 is prepared by taking cellulose nanocrystals CNC as a matrix, diethylenetriamine pentaacetic acid DTPA as a collecting agent, gamma-mercaptopropyltrimethoxysilane MPTMS as a cross-linking agent and chitosan quaternary ammonium salt HTCC as a flocculating agent through the steps of main reaction and post-treatment. The nano structure of the CNC substrate can uniformly load DTPA and MPTMS to provide a stable framework; a collecting agent DTPA is extremely high in chelating capacity for lead ions and is not combined with silver ions, and loss of precious metal is avoided; mPTMS can strengthen the structural stability of the medicament; the HTCC has flocculation activity and can promote agglomeration of the nanoparticles.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy and chemical engineering, specifically relating to a lead removal agent FT236, its preparation method, and its application. Background Technology

[0002] With the rapid development of industries such as electronic information, photovoltaic energy storage, and precision manufacturing of precious metals, the market demand for high-purity silver nitrate continues to rise. As a key raw material, silver nitrate is widely used in core areas such as chip electroplating, photovoltaic silver paste preparation, and medical antibacterial materials; its purity directly determines the performance of the end products. However, current research on lead removal and purification of silver nitrate solutions faces multiple challenges: On the one hand, the silver nitrate solution system has significant unique characteristics; different sources of silver raw materials lead to large fluctuations in lead ion concentration (5-500 mg / L), and it often coexists with metal ions such as copper, iron, and lead to form a complex system. Traditional lead removal methods (such as sulfide precipitation) are easily affected by acidic environments, making it difficult to achieve precise lead separation. On the other hand, existing technologies have significant shortcomings. While chemical precipitation is simple to operate, it results in a high silver loss rate. Traditional resin adsorbents have poor acid resistance, low adsorption capacity, and long regeneration cycles, making it difficult to meet the stringent standards for electronic-grade silver nitrate. Therefore, developing acid-resistant, stable, highly selective, and low-silver-loss silver nitrate solution technology for lead removal, thereby improving lead removal rate and silver nitrate product purity, has become a key research direction for ensuring the high-quality development of strategic industries such as electronics and photovoltaics, promoting the efficient recycling of precious metal resources, and assisting the green and low-carbon transformation of the smelting industry. Summary of the Invention

[0003] The first objective of this invention is to provide a lead removal agent FT236; the second objective is to provide a method for preparing the lead removal agent FT236; and the third objective is to provide applications of the lead removal agent FT236.

[0004] The first objective of this invention is achieved as follows: the lead removal agent FT236 is prepared by using cellulose nanocrystals (CNC) as the matrix, diethyltriaminepentaacetic acid (DTPA) as the collector, γ-mercaptopropyltrimethoxysilane (MPTMS) as the crosslinking agent, and chitosan quaternary ammonium salt (HTCC) as the flocculant, through a main reaction and post-treatment steps.

[0005] The second objective of this invention is achieved by including a main reaction and a post-processing step, specifically including: A. Main reaction: The cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) in the formula ratio are added to the reaction vessel for a solvothermal reaction to obtain material a. B. Post-processing: 1) After material a is naturally cooled to below 80℃, product b is obtained; 2) After filtering, washing and drying product b, the lead removal agent FT236 is obtained.

[0006] The third objective of this invention is achieved by the application of the lead removal agent FT236 in the lead removal process.

[0007] The synergistic mechanism of this invention is as follows: the nanostructure of the CNC matrix can uniformly load DTPA and MPTMS, providing a stable framework; the collector DTPA has a strong chelating ability for lead ions without binding with silver ions, thus avoiding the loss of precious metals; MPTMS can enhance the structural stability of the agent; HTCC has flocculation activity and can promote the aggregation of nanoparticles. Detailed Implementation

[0008] The present invention will be further described below with reference to embodiments, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0009] The lead removal agent FT236 described in this invention is prepared by using cellulose nanocrystals (CNC) as the matrix, diethyltriaminepentaacetic acid (DTPA) as the collector, γ-mercaptopropyltrimethoxysilane (MPTMS) as the crosslinking agent, and chitosan quaternary ammonium salt (HTCC) as the flocculant, through a main reaction and post-treatment steps.

[0010] The molar ratio of the cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:(3~8):(1.5~3):(0.5~1).

[0011] The preparation method of the lead removal agent FT236 of the present invention includes a main reaction and a post-processing step, specifically including: A. Main reaction: The cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) in the formula ratio are added to the reaction vessel for a solvothermal reaction to obtain material a. B. Post-processing: 1) After material a is naturally cooled to below 80℃, product b is obtained; 2) After filtering, washing and drying product b, the lead removal agent FT236 is obtained.

[0012] The reaction pressure in step A is 8~12 MPa.

[0013] The reaction temperature in step A is 180~240℃.

[0014] The reaction time in step A is 3-5 hours.

[0015] The application of this invention is the use of the lead removal agent FT236 in the lead removal process.

[0016] The lead removal process involves removing lead ions using the lead removal agent FT236 in a strongly acidic, high-temperature silver nitrate system.

[0017] The nitric acid concentration of the strongly acidic high-temperature silver nitrate system is 3~6 mol / L.

[0018] The high temperature of the strongly acidic high-temperature silver nitrate system is 80~120℃.

[0019] The invention will be further illustrated below with specific implementation examples: Example 1

[0020] Cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) were added to a reaction vessel for a solvothermal reaction to obtain material a; material a was naturally cooled to below 80°C to obtain product b; product b was filtered, washed, and dried to obtain the target lead removal agent FT236.

[0021] The molar ratio of cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:3:1.5:0.5.

[0022] Example 2

[0023] Cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) were added to a reaction vessel for a solvothermal reaction to obtain material a; material a was naturally cooled to below 80°C to obtain product b; product b was filtered, washed, and dried to obtain the target lead removal agent FT236.

[0024] The molar ratio of cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:8:3:1.

[0025] Example 3

[0026] Cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) were added to a reaction vessel for a solvothermal reaction to obtain material a; material a was naturally cooled to below 80°C to obtain product b; product b was filtered, washed, and dried to obtain the target lead removal agent FT236.

[0027] The molar ratio of cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:(3~8):(1.5~3):(0.5~1).

[0028] Example 4

[0029] Cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) were added to a reaction vessel for a solvothermal reaction to obtain material a; material a was naturally cooled to below 80°C to obtain product b; product b was filtered, washed, and dried to obtain the target lead removal agent FT236.

[0030] The molar ratio of cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:5:2.6:0.75.

[0031] Example 5

[0032] Cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) were added to a reaction vessel for a solvothermal reaction to obtain material a; material a was naturally cooled to below 80°C to obtain product b; product b was filtered, washed, and dried to obtain the target lead removal agent FT236.

[0033] The molar ratio of cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:6:2:0.7.

[0034] Experimental Example 1 The lead removal agent FT236 prepared in Example 3 was used for testing: The lead removal agent FT236 prepared in Example 3 was added to a silver nitrate solution containing 10-50 mg / L of lead at a rate of 0.2-0.8% of the silver nitrate solution volume (i.e., 0.2-0.8 g of agent per 100 mL of solution). The mixture was stirred to ensure thorough mixing. The reaction temperature was controlled at 80-85℃ and the system pH at 2.0-3.0, and the reaction was carried out at this constant temperature for 30-60 minutes. After the reaction, the solution was filtered through a microporous membrane. Ultimately, the lead removal rate from the silver nitrate solution was 99.83%, and the residual lead content in the treated silver nitrate solution was 0.02 mg / L; the silver loss rate was less than 0.01%.

[0035] Comparative Example 1 A domestic precious metal smelting enterprise used a sulfide precipitation method to treat lead impurities in silver nitrate solution. A 10% sodium sulfide solution was added dropwise to a silver nitrate solution with a lead concentration of 50-100 mg / L. The reaction pH was controlled at 2.0-2.5, the temperature at 30-40℃, and the mixture was stirred for 60 minutes, followed by standing precipitation for 30 minutes. The lead sulfide precipitate was then separated by filtration. This process achieved a lead removal rate of up to 98.5%, but the silver loss rate was relatively high. The School of Metallurgy at Northeastern University used D301 macroporous weakly basic anion exchange resin. Under conditions of 25℃ and pH=2.5, the resin was mixed with a silver nitrate solution containing 10 mg / L lead at a solid-liquid ratio of 1:200, and the mixture was shaken for 4 hours for adsorption. The results showed that the static adsorption capacity of the resin for lead ions reached 5.76 mg / g.

[0036] Experimental Example 2 The lead removal agent FT236 prepared in Examples 1, 2, 4 and 5 were tested respectively, using the same method as in Example 1. The results all showed that the lead removal agent FT236 of the present invention had a lead removal rate of more than 99.5%, and the lead residue in the treated silver nitrate solution was ≤0.05mg / L; the silver loss rate was less than 0.01%.

Claims

1. A lead removal agent FT236, characterized in that, The lead removal agent FT236 is prepared by a main reaction and post-treatment steps using cellulose nanocrystals (CNC) as the matrix, diethyltriaminepentaacetic acid (DTPA) as the collector, γ-mercaptopropyltrimethoxysilane (MPTMS) as the crosslinking agent, and chitosan quaternary ammonium salt (HTCC) as the flocculant.

2. The lead removal agent FT236 according to claim 1, characterized in that, The molar ratio of the cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) is 1:(3~8):(1.5~3):(0.5~1).

3. A method for preparing the lead-removing agent FT236 as described in claim 1 or 2, characterized in that, It includes the main reaction and post-processing steps, specifically including: A. Main reaction: The cellulose nanocrystals (CNC), diethyltriaminepentaacetic acid (DTPA), γ-mercaptopropyltrimethoxysilane (MPTMS), and chitosan quaternary ammonium salt (HTCC) in the formula ratio are added to the reaction vessel for a solvothermal reaction to obtain material a. B. Post-processing: 1) After material a is naturally cooled to below 80℃, product b is obtained; 2) After filtering, washing and drying product b, the lead removal agent FT236 is obtained.

4. The preparation method according to claim 3, characterized in that, The reaction pressure in step A is 8~12 MPa.

5. The preparation method according to claim 3, characterized in that, The reaction temperature in step A is 180~240℃.

6. The preparation method according to claim 3, characterized in that, The reaction time in step A is 3-5 hours.

7. The application of the lead removal agent FT236 as described in claim 1 or 2, characterized in that, The application of the lead removal agent FT236 in the lead removal process.

8. The application according to claim 7, characterized in that, The lead removal process involves removing lead ions using the lead removal agent FT236 in a strongly acidic, high-temperature silver nitrate system.

9. The application according to claim 7, characterized in that, The nitric acid concentration of the strongly acidic high-temperature silver nitrate system is 3~6 mol / L.

10. The application according to claim 7, characterized in that, The high temperature of the strongly acidic high-temperature silver nitrate system is 80~120℃.