CN110975836B - A kind of pomelo peel adsorbent modified with 3-amino-5-mercapto-1,2,4-triazole and its preparation method and application - Google Patents

Abstract

The invention discloses a 3-amino-5-mercapto-1, 2, 4-triazole modified shaddock peel adsorbent, and a preparation method and application thereof, and belongs to the field of adsorbent preparation. Firstly, drying the shaddock peel, performing ball milling to obtain powder, and activating by concentrated sulfuric acid to obtain PP-SC. Then reacting with chloroacetyl chloride under anhydrous condition to obtain PP-CC. And finally, carrying out reflux reaction on the PP-CC and the 3-amino-5-mercapto-1, 2, 4-triazole to obtain the PP-ATT adsorbent. The preparation method of the adsorbent is simple and feasible, the operation is simple and convenient, and the raw materials are cheap and easy to obtain. The obtained novel shaddock peel modified material has high-efficiency and high-selectivity effects on removal of lead ions in an aqueous solution, and can be recycled. The invention provides a green and efficient adsorbent for treating the lead-containing wastewater, provides a method for recycling agricultural wastes, and brings a new idea for designing and synthesizing a novel adsorbent.

Description

A pomelo peel adsorbent modified with 3-amino-5-mercapto-1,2,4-triazole and its preparation Preparation method and application

technical field

The invention relates to a 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent and a preparation method and application thereof, belonging to the technical field of adsorbent preparation.

Background technique

Lead (Pb) has long been listed by the World Health Organization as one of the most harmful pollutants due to its high toxicity, carcinogenicity, bioaccumulation and non-degradability. With the development of industries such as battery manufacturing, petroleum refining, mineral smelting, and paint production, a large amount of lead ions enter the water circulation system, posing a huge threat to organisms. After entering the human body through inhalation, lead will cause irreversible damage to the nerves, reproduction, brain, kidney, liver and blood system; even at low levels, it will have more serious effects. Therefore, it is necessary to take effective measures to control lead pollution. At the same time, lead is widely used in industry due to its lower melting point, corrosion resistance, reshaping properties, etc. Therefore, the recovery of lead has also become an important subject of research in engineering fields such as the environment and materials. At present, the main removal methods of lead include precipitation method, biological method, electrochemical method, ion exchange method and adsorption method. The chemical precipitation method will produce secondary pollution, and the selectivity is poor; the biological method is limited due to the small number of special microorganisms and short life; the ion exchange method and the electrochemical method are relatively high in cost and poor in repeatability. The adsorption method is considered to be one of the most effective methods because of its simple operation, repeatability, selectivity, and no secondary pollution. Commonly used adsorbents include activated carbon, resin, natural minerals, agricultural by-products, silica, etc. Pomelo peel is a kind of agricultural waste, which is usually disposed of by landfill and incineration, causing resource waste and environmental pollution. However, pomelo peel is rich in amino groups and hydroxyl groups, and is a high-quality and low-cost material for post-modification.

Contents of the invention

In view of the problems and deficiencies in the above-mentioned prior art, the object of the present invention is to provide a preparation and application of a 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent. The modified pomelo peel adsorbent can be used for selective removal of lead ions in acidic aqueous solution, has low material cost, simple synthesis process, is easy to separate from aqueous solution, has high adsorption capacity and can be used repeatedly.

The present invention is realized through the following technical solutions:

A 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent, the structural formula of which is shown in formula (I):

为浓硫酸活化后暴露羟/氨基的柚皮示意结构；in

Schematic structure of pomelo peel exposed to hydroxyl/amino groups after activation by concentrated sulfuric acid;

R is:

Another object of the present invention is to provide the preparation method of the described pomelo peel adsorbent modified with 3-amino-5-mercapto-1,2,4-triazole, the steps are as follows:

(1) Cut the pomelo peel into small pieces, dry it, and grind it into powder with a small ball mill; take the pomelo peel powder into a beaker, add 98wt% concentrated sulfuric acid for pretreatment, transfer it to a round-bottomed three-neck flask, and reflux at 100°C Stirring activation treatment to expose surface functional groups, liquid-solid separation after reflux, the resulting solid was washed with deionized water until neutral, and dried to obtain the product PP-SC, the reaction process is shown in Figure 1.

(2) In an anhydrous environment, take the product PP-SC and chloroacetyl chloride of step (1) and sequentially add them to N,N-dimethylformamide solution for reflux reaction. The dimethylformamide solution is washed and centrifuged and dried in vacuum to obtain the product PP-CC; the reaction scheme is as follows:

(3) Under the protection of nitrogen, the product PP-CC and 3-amino-5-mercapto-1,2,4-triazole obtained in step (2) were sequentially added to N,N-dimethylformamide and refluxed After the reaction, the liquid and solid were separated, and the obtained solid was washed with N,N-dimethylformamide and then vacuum-dried to obtain the product PP-ATT; the synthesis route is as follows:

As a preference, in the above preparation method: the liquid-solid ratio of concentrated sulfuric acid to pomelo peel powder in step (1) is 3:1-7:1mL/g.

As preferred, in the above preparation method: the liquid-solid ratio of N,N-dimethylformamide and PP-SC described in step (2) is 30:1～50:1mL/g, chloroacetyl chloride and PP-SC The liquid-solid ratio of SC is 5:3～10:3.

As a preference, in the above preparation method: the liquid-solid ratio of N,N-dimethylformamide to PP-CC in step (3) is 40:1～56:1mL/g, 3-amino-5 The mass ratio of mercapto-124 triazole to PP-CC is 2:5～1:1.

Preferably, in the above preparation method: the reflux in step (1) is to react at 50-100°C for 5-15h; the reflux in step (2) is to react at 80-100°C for 12-15h; 24h; the reflux in step (3) is to react at 45-85°C for 12-24h.

The application of the above-mentioned 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent in selective adsorption and removal of lead ions in acidic aqueous solution.

The above-mentioned organic reagents and inorganic reagents are commercially available analytically pure.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The 3-amino-5-mercapto-1,2,4-triazole modified pomelo adsorbent of the present invention has better selectivity, higher adsorption capacity and excellent removal rate for lead ion adsorption .

(2) The preparation process of the adsorbent of the present invention is simple, easy to synthesize, and the cost of raw materials is low.

(3) The 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent of the present invention is non-toxic, stable in performance, easy to separate, reusable, and has no secondary pollution to the environment.

(4) The modified pomelo peel adsorbent of the present invention has good economic and practical value. It has great potential for generalization in the selective removal and recovery of lead ions in aqueous solution.

Description of drawings

Figure 1 is a schematic diagram of the reaction process of step (1).

detailed description

The present invention will be further described below in combination with specific embodiments.

Example 1:

The 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent has a structural formula of:

为浓硫酸活化后暴露羟/氨基的柚皮示意结构；in

Schematic structure of pomelo peel exposed to hydroxyl/amino groups after activation by concentrated sulfuric acid;

R is:

The preparation of the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent, the specific steps are as follows:

(1) Cut the pomelo peel into small pieces of about 1 cm, dry it, and grind it to powder with a small ball mill. Take 10g of pomelo peel powder into a 1L beaker, add 98wt% concentrated sulfuric acid for pretreatment for 3 hours according to the liquid-solid ratio of concentrated sulfuric acid and pomelo peel powder at a ratio of 3:7, transfer it to a three-neck round bottom flask, and reflux at 50°C for 5 hours to activate Surface functional groups, liquid-solid separation after the reaction, the obtained solid was washed with deionized water until neutral, and the product PP-SC was obtained after centrifugal drying; the reaction process is shown in Figure 1.

(2) In an anhydrous environment, mix N,N-dimethylformamide solution and PP-SC according to the liquid-solid ratio of 30:1mL/g, and then according to the liquid-solid ratio of chloroacetyl chloride and PP-SC Add chloroacetyl chloride at 5:3, reflux at 80°C for 12 hours, and then separate liquid from solid. The resulting solid is washed with N,N-dimethylformamide and centrifuged, then vacuum-dried to obtain the product PP-CC; the synthetic route is as follows:

(3) Under a nitrogen protection environment, mix the PP-CC obtained in step (2) with N,N-dimethylformamide according to a solid-to-liquid ratio of 1:40g/mL, and then mix according to the 3-amino-5- The mass ratio of mercapto-1,2,4-triazole to PP-CC is 2:5, add 3-amino-5-mercapto-1,2,4-triazole, reflux at 45°C for 12 hours, and then liquid-solid After separation, the resulting solid was washed with N,N-dimethylformamide and centrifuged to obtain the product PP-ATT; the synthetic route is as follows:

Determination of adsorption performance of lead ions:

Get 10mg of PP-ATT in this embodiment and put it into the lead ion solution whose initial concentration is 200mg/L and centrifuge after shaking and adsorbing for 2h. Utilize ICP-OES to measure the remaining lead ion concentration in the supernatant to be 19.7mg/L, and the adsorption rate was 90.15%. The bottom solid was desorbed with thiourea solution (10wt%) for 12h and washed 3 times. After drying for 24h at 65°C, it was thrown into the lead ion solution with an initial concentration of 200mg/L and centrifuged for 2h after shaking and adsorbing. Measure the supernatant. The remaining lead ion concentration in the liquid is 23.12mg/L, and the adsorption rate is 88.44%. It shows that the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent PP-ATT of the present invention can be repeatedly used to remove lead ions in aqueous solution.

Example 2:

The 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent has a structural formula of:

为浓硫酸活化后暴露羟/氨基的柚皮示意结构；in

Schematic structure of pomelo peel exposed to hydroxyl/amino groups after activation by concentrated sulfuric acid;

R is:

The preparation of the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent, the specific steps are as follows:

(1) Cut the pomelo peel into small pieces of about 1 cm, dry it, and grind it to powder with a small ball mill. Take 10g of pomelo peel powder into a 1L beaker, add 98wt% concentrated sulfuric acid for pretreatment for 3 hours according to the liquid-solid ratio of concentrated sulfuric acid and pomelo peel powder at a liquid-solid ratio of 5:7, then transfer to a round-bottomed three-necked flask, and reflux at 75°C for 10 hours to activate Surface functional groups, liquid-solid separation after the reaction, the obtained solid is washed with deionized water until neutral, and the product PP-SC is obtained after drying; the reaction process is shown in Figure 1

(2) In an anhydrous environment, mix N,N-dimethylformamide solution and PP-SC according to the liquid-solid ratio of 40:1mL/g, and then according to the liquid-solid ratio of chloroacetyl chloride and PP-SC Add chloroacetyl chloride at 5:2, reflux at 90°C for 18 hours, and then separate the liquid from the solid. The resulting solid is washed with N,N-dimethylformamide and centrifuged, then vacuum-dried to obtain the product PP-CC; the synthetic route is as follows:

(3) Under a nitrogen protection environment, mix the PP-CC obtained in step (2) with N,N-dimethylformamide according to a solid-to-liquid ratio of 1:48g/mL, and then mix according to the 3-amino-5- The mass ratio of mercapto-1,2,4-triazole to PP-CC is 7:10, add 3-amino-5-mercapto-1,2,4-triazole, reflux at 85°C for 18 hours, and then liquid-solid After separation, the resulting solid was washed with N,N-dimethylformamide and centrifuged to obtain the product PP-ATT; the synthetic route is as follows:

Determination of adsorption performance of lead ions:

Get 10mg of PP-ATT adsorbent in this embodiment and put it into the lead ion solution whose initial concentration is 200mg/L and centrifuge after shaking and adsorbing for 2h, and utilize ICP-OES to measure the remaining lead ion concentration in the supernatant to be 13.34mg/L. The adsorption rate was 93.33%. The bottom solid was desorbed with thiourea solution (10wt%) for 12h, washed with water, dried at 65°C for 24h, then thrown into the lead ion solution with an initial concentration of 200mg/L and centrifuged for 2h and then centrifuged to measure the supernatant. The remaining lead ion concentration in the medium is 16.38mg/L, and the adsorption rate is 91.81%. It shows that the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent PP-ATT of the present invention can be repeatedly used to remove lead ions in aqueous solution.

Example 3:

The 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent has a structural formula of:

为浓硫酸活化后暴露羟/氨基的柚皮示意结构；in

Schematic structure of pomelo peel exposed to hydroxyl/amino groups after activation by concentrated sulfuric acid;

R is:

The preparation of the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent, the specific steps are as follows:

(1) Cut the pomelo peel into small pieces of about 1 cm, dry it, and grind it to powder with a small ball mill. Take 10g of pomelo peel powder into a 1L beaker, and add 98wt% concentrated sulfuric acid for pretreatment for 3 hours according to the liquid-solid ratio of concentrated sulfuric acid and pomelo peel powder at a liquid-solid ratio of 7:1. Transfer to a round-bottomed three-neck flask, reflux at 100°C for 15 hours to activate surface functional groups, separate liquid and solid after the reaction, wash the obtained solid with deionized water until neutral, and dry to obtain the product PP-SC; the reaction process is shown in the figure 1.

(2) In an anhydrous environment, mix N,N-dimethylformamide solution and PP-SC according to the liquid-solid ratio of 50:1mL/g, and then according to the liquid-solid ratio of chloroacetyl chloride and PP-SC Chloroacetyl chloride was added at 10:3, reflux reaction at 100°C for 24 hours, and liquid-solid separation was performed. The resulting solid was washed with N,N-dimethylformamide and centrifuged, then vacuum-dried to obtain the product PP-CC; the specific synthetic route is as follows:

(3) Under a nitrogen protection environment, mix the PP-CC obtained in step (2) with N,N-dimethylformamide according to a solid-to-liquid ratio of 1:56g/mL, and then mix according to the 3-amino-5- The mass ratio of mercapto-1,2,4-triazole to PP-CC is 1:1, add 3-amino-5-mercapto-1,2,4-triazole, and reflux at 65°C for 24 hours. Solid separation, the resulting solid was washed with N,N-dimethylformamide and centrifuged to obtain the product PP-ATT; the specific synthetic route is as follows:

Determination of adsorption performance of lead ions:

Get 10mg of PP-ATT adsorbent in this embodiment and drop into the lead ion solution that initial concentration is 200mg/L centrifugation after vibration adsorption 2h, utilize ICP-OES to measure residual lead ion concentration in the supernatant to be 2.04mg/L, The adsorption rate is 98.98%. The bottom solid was desorbed with thiourea solution (10wt%) for 12h and then washed by centrifugation. After drying for 24h under the condition of 65°C, it was thrown into the lead ion solution with an initial concentration of 200mg/L and centrifuged for 2h after shaking and adsorbing for 2h. Measure the supernatant. The remaining lead ion concentration in the liquid is 3.57mg/L, and the adsorption rate is 98.22%. It shows that the 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent PP-ATT of the present invention can be repeatedly used to remove lead ions in aqueous solution.

The specific implementation of the present invention has been described in detail above, but the present invention is not limited to the above-mentioned implementation, within the knowledge of those of ordinary skill in the art, various modifications can be made without departing from the spirit of the present invention. Variety.

Claims (1)

1. The application of 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent in selective adsorption and removal of lead ions in acidic aqueous solution, characterized in that: The structural formula of 3-amino-5-mercapto-1,2,4-triazole modified pomelo peel adsorbent is:

in

Schematic structure of pomelo peel exposed to hydroxyl and amino groups after activation by concentrated sulfuric acid; R is:

Proceed as follows: (1) Cut the pomelo peel into small pieces, dry it, and grind it into powder with a small ball mill; take 10g of pomelo peel powder into a 1L beaker, and add 98wt% according to the liquid-solid ratio of concentrated sulfuric acid to pomelo peel powder: 7:1ml/g Concentrated sulfuric acid pretreatment for 3 hours; transfer to a three-necked round-bottomed flask, reflux at 100°C for 15 hours to activate surface functional groups, separate liquid and solid after the reaction, wash the obtained solid with deionized water until neutral, and dry to obtain the product PP- SC; (2) In an anhydrous environment, mix N,N-dimethylformamide solution and PP-SC according to the liquid-solid ratio of 50:1mL/g, and then according to the liquid-solid ratio of chloroacetyl chloride and PP-SC Add chloroacetyl chloride at 10:3, reflux at 100°C for 24 hours, and then separate the liquid from the solid. The obtained solid is washed with N,N-dimethylformamide and centrifuged, then vacuum-dried to obtain the product PP-CC; the synthetic route is as follows:

(3) Under a nitrogen protection environment, mix the PP-CC obtained in step (2) with N,N-dimethylformamide according to a solid-to-liquid ratio of 1:56g/mL, and then mix according to the 3-amino-5- The mass ratio of mercapto-1,2,4-triazole to PP-CC is 1:1, add 3-amino-5-mercapto-1,2,4-triazole, and reflux at 65°C for 24 hours. Solid separation, the resulting solid was washed with N,N-dimethylformamide and centrifuged to obtain the product PP-ATT; the synthetic route is as follows:

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