Silver ion organic adsorbent and preparation method and application thereof

Abstract

The invention relates to a silver ion organic adsorbent and a preparation method and application thereof, and belongs to the technical field of composite materials. The silver ion organic adsorbent BPD-POP is generated through reaction of 4, 4-dipyridyl, pyrrole and dimethoxymethane, the structural formula of the silver ion organic adsorbent BPD-POP is # imgabs0, and the silver ion organic adsorbent BPD-POP can be used for efficiently and selectively adsorbing silver ions from a solution and has high cyclic regeneration capacity.

Description

Technical Field

[0001] The invention relates to a silver ion organic adsorbent and a preparation method and application thereof, belonging to the technical field of composite materials. Background Art

[0002] There are many methods to remove metal ions from aqueous solutions, such as membrane separation, electrochemical methods, chemical precipitation and adsorption. Adsorption is considered to be the most effective method because of its simple operation and no secondary pollution. A variety of adsorbents have been developed for the adsorption of silver ions, including biochar, diatomaceous earth, graphene oxide and covalent organic frameworks. In order to improve the adsorption efficiency, functional groups such as thiols, rhodanine, thioglycolic acid and trimercaptotriazine have also been introduced, but the introduction of these functional groups usually requires a complex synthesis process.

[0003] Porous materials with large surface areas Porous organic polymers show great potential in the field of adsorption. Porous organic polymers are suitable for metal ion adsorption due to their high porosity, large surface area, and stable physicochemical properties. Porous organic polymers with specific groups can improve the adsorption capacity and selectivity for various metals.

[0004] The adsorption capacity of existing silver ion adsorbents is still insufficient for high concentrations of silver ions. Although the introduction of specific functional groups has improved the adsorption efficiency, the synthesis conditions are harsh and the synthesis process is complex. In addition, the inefficient binding mechanism and poor optimization of functional groups in the adsorbent structure lead to low adsorption capacity and selectivity. Many silver ion adsorbents face difficulties in regeneration and reuse due to chemical or structural degradation during the regeneration process, and repeated use usually leads to a significant decrease in adsorption efficiency. By addressing these challenges through innovative design and enhanced material stability, silver ion adsorbents can be further optimized for wider application in water treatment and other fields. Summary of the invention

[0005] In view of the problems of poor selectivity and difficult recovery of existing silver ion adsorbents, the present invention proposes an organic adsorbent for silver ions and a preparation method and application thereof. The organic adsorbent for silver ions BPD-POP is produced by the reaction of 4,4-bipyridine with pyrrole and dimethoxymethane. The organic adsorbent for silver ions can be used to efficiently and selectively adsorb silver ions from a solution and has a strong recycling and regeneration ability.

[0006] A silver ion organic adsorbent, which is produced by the reaction of 4,4-bipyridine with pyrrole and dimethoxymethane, and is denoted as adsorbent BPD-POP, and has the structural formula:

[0007]

[0008] The preparation method of the silver ion organic adsorbent comprises the following specific steps:

[0009] (1) stirring and dissolving pyrrole and dimethoxymethane in N,N-dimethylformamide solvent to obtain solution A;

[0010] (2) stirring and dissolving 4,4-bipyridine in solution A to obtain solution B;

[0011] (3) adding anhydrous FeCl3 to solution B, stirring and reacting at a temperature of 30 to 50°C for 1 to 3 hours to obtain solution C;

[0012] (4) placing solution C in a high pressure reactor, reacting at a temperature of 90 to 110° C. for 45 to 55 hours, cooling to room temperature, separating the solid and the liquid, soaking the solid in ethanol for 6 to 24 hours, then washing with ethanol and deionized water in turn, and vacuum drying to obtain the silver ion organic adsorbent BPD-POP; the chemical reaction formula is:

[0013]

[0014] Preferably, in step (1), the volume ratio of pyrrole to dimethoxymethane is 1:2.1-2.4, and the concentration of pyrrole in solution A is 0.1-0.3 mol / L.

[0015] Preferably, the solid-to-liquid ratio g:mL of the 4,4-bipyridine in step (2) to the pyrrole in step (1) is 1:0.3-1.5.

[0016] Preferably, the solid-to-liquid ratio g:mL of the anhydrous FeCl3 in step (3) to the pyrrole in step (1) is 1:0.3-0.8.

[0017] The silver ion organic adsorbent can be used to efficiently and selectively adsorb silver ions from a solution.

[0018] The cyclic regeneration method of the silver ion organic adsorbent comprises the following steps: using a desorption solution mixture consisting of 1% concentrated hydrochloric acid and 10% thiourea as a desorbent, and washing after desorption to complete the cyclic regeneration of the adsorbent.

[0019] The principle of the silver ion organic adsorbent of the present invention for selectively adsorbing silver ions is as follows: the organic adsorbent BPD-POP has the characteristics of large specific surface area and rigid structure; the N-containing functional groups it has include -NH, -C=N, and -CN; the large pore size and specific surface area make it have strong adsorption capacity, and a large number of N-containing functional groups can chelate with Ag(I) to selectively adsorb Ag(I) in the solution.

[0020] The beneficial effects of the present invention are:

[0021] (1) The silver ion organic adsorbent of the present invention can efficiently and selectively adsorb silver ions in the solution due to its surface electrostatic effect and N-functional group, and has a strong recycling regeneration ability;

[0022] (2) The preparation method of the silver ion organic adsorbent of the present invention is simple, flexible and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the SEM image of the silver ion organic adsorbent of Example 1;

[0024] Figure 2 This is the EDS image of the silver ion organic adsorbent of Example 1;

[0025] Figure 3 This is the BET diagram of the silver ion organic adsorbent of Example 1;

[0026] Figure 4 The XRD diagram of the silver ion organic adsorbent in Example 1 before and after the adsorption of silver ions;

[0027] Figure 5 This is the FT-IR image of the silver ion organic adsorbent of Example 1;

[0028] Figure 6 FT-IR images of the silver ion organic adsorbents of Examples 1, 2 and 3 after cyclic regeneration. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0030] Embodiment 1: A method for preparing a silver ion organic adsorbent, the specific steps are as follows:

[0031] (1) stirring and dissolving pyrrole and dimethoxymethane in an N,N-dimethylformamide solvent to obtain a solution A; the volume ratio of pyrrole to dimethoxymethane is 1:2.2, and the concentration of pyrrole in the solution A is 0.2 mol / L;

[0032] (2) stirring and dissolving 4,4-bipyridine in solution A to obtain solution B; the 4,4-bipyridine and step (1)

[0033] The solid-liquid ratio of pyrrole g:mL is 1:1.3;

[0034] (3) adding anhydrous FeCl3 to solution B, stirring and reacting at a temperature of 35°C for 2 hours to obtain solution C; the solid-liquid ratio of the anhydrous FeCl3 to the pyrrole in step (1) is 1:0.4 g:mL;

[0035] (4) Solution C was placed in a high pressure reactor, reacted at a temperature of 100° C. for 48 h, cooled to room temperature, and then the solid and liquid were separated. The solid was soaked in ethanol for 15 h, and then washed with ethanol and deionized water in turn, and vacuum dried to obtain the silver ion organic adsorbent BPD-POP; the chemical reaction formula is as follows:

[0036]

[0037] The results of SEM, EDS, BET, XRD, FT-IR and FT-IR after cyclic regeneration of the silver ion organic adsorbent BPD-POP in this example are shown in Figure 1-6 As can be seen from the figure, the silver ion organic adsorbent BPD-POP is mainly composed of elements C and N, with the weight percentages of C and N being 62.77% and 37.23% respectively; from the XRD spectrum, it can be seen that the crystallinity of BPD-POP is low, which is consistent with the amorphous nature of the polymer; in the FT-IR spectrum, at 1388cm -1 、1348cm -1 and 1085cm -1 The characteristic fronts belonging to -C=N and -CN appeared; 3500cm -1 The vibration peak of -NH near the silver ion further confirmed that the organic adsorbent BPD-POP was successfully synthesized; after cyclic regeneration, the structure of the organic adsorbent did not change and its properties were stable;

[0038] The selective adsorption performance of silver ions by the organic adsorbent BPD-POP of silver ions in this example is measured:

[0039] BPD-POP (10 mg) and a solution to be adsorbed (pH = 1, 10 mL) were added to a 15 mL centrifuge tube at room temperature, wherein the solution to be adsorbed contained 163.92 mg / L of Ag(I), 187.16 mg / L of Ca(II), 164.81 mg / L of Ni(II), 159.82 mg / L of Co(II), 150.35 mg / L of Al(III), and 132.6 mg / L of Mg(II); the mixture was shaken at 200 rpm for 20 h on an oscillator; the adsorbent was separated by centrifugation and the supernatant was obtained, and the residual concentration of the remaining metal ions in the supernatant was determined by ICP-OES;

[0040] The removal rates of Ag(I) were calculated to be 99.38%, Ca(II) to be 3.33%, Ni(II) to be 13.05%, Co(II) to be 0.81%, Al(III) to be 4.44%, and Mg(II) to be 7.56%.

[0041] It can be seen that the silver ion organic adsorbent BPD-POP of this embodiment has strong selectivity for silver ions;

[0042] The regeneration performance of the silver ion organic adsorbent BPD-POP in this example is measured:

[0043] The adsorbent was eluted with a desorbent (a desorption solution mixture consisting of 1% concentrated hydrochloric acid and 10% thiourea), centrifuged, and then washed with distilled water until the solution became neutral to complete the regeneration of the adsorbent BPD-POP; after 4 repeated experiments, the fourth Ag(I) removal rate was 77.41%.

[0044] Embodiment 2: A method for preparing a silver ion organic adsorbent, the specific steps are as follows:

[0045] (1) stirring and dissolving pyrrole and dimethoxymethane in an N,N-dimethylformamide solvent to obtain a solution A; the volume ratio of pyrrole to dimethoxymethane is 1:2.3, and the concentration of pyrrole in the solution A is 0.1 mol / L;

[0046] (2) stirring and dissolving 4,4-bipyridine in solution A to obtain solution B; the 4,4-bipyridine and step (1)

[0047] The solid-liquid ratio of pyrrole g:mL is 1:0.9;

[0048] (3) adding anhydrous FeCl3 to solution B, stirring and reacting at a temperature of 40°C for 1.5 hours to obtain solution C; the solid-liquid ratio of the anhydrous FeCl3 to the pyrrole in step (1) is 1:0.5 g:mL;

[0049] (4) placing solution C in a high pressure reactor, reacting at a temperature of 105° C. for 45 h, cooling to room temperature and separating the solid and liquid, soaking the solid in ethanol for 20 h, then washing with ethanol and deionized water in turn, and vacuum drying to obtain the silver ion organic adsorbent BPD-POP;

[0050] The selective adsorption performance of silver ions by the organic adsorbent BPD-POP of silver ions in this example is measured:

[0051] BPD-POP (10 mg) and a solution to be adsorbed (pH = 1, 10 mL) were added to a 15 mL centrifuge tube at room temperature, wherein the solution to be adsorbed contained 163.92 mg / L of Ag(I), 187.16 mg / L of Ca(II), 164.81 mg / L of Ni(II), 159.82 mg / L of Co(II), 150.35 mg / L of Al(III), and 132.6 mg / L of Mg(II); the mixture was shaken at 200 rpm for 20 h on an oscillator; the adsorbent was separated by centrifugation and the supernatant was obtained, and the residual concentration of the remaining metal ions in the supernatant was determined by ICP-OES;

[0052] The removal rates of Ag(I) were calculated to be 99.49%, Ca(II) to be 0.81%, Ni(II) to be 12.97%, Co(II) to be 1.16%, Al(III) to be 2.47%, and Mg(II) to be 9.01%.

[0053] It can be seen that the silver ion organic adsorbent BPD-POP of this embodiment has strong selectivity for silver ions;

[0054] The regeneration performance of the silver ion organic adsorbent BPD-POP in this example is measured:

[0055] The adsorbent was eluted with a desorbent (a desorption solution mixture consisting of 1% concentrated hydrochloric acid and 10% thiourea) and then centrifuged and washed with distilled water until the solution was neutral to complete the regeneration of the adsorbent BPD-POP. After 4 repeated experiments, the removal rate of Ag(I) in the fourth time was 72.91%.

[0056] Embodiment 3: A method for preparing a silver ion organic adsorbent, the specific steps are as follows:

[0057] (1) stirring and dissolving pyrrole and dimethoxymethane in an N,N-dimethylformamide solvent to obtain a solution A; the volume ratio of pyrrole to dimethoxymethane is 1:2.1, and the concentration of pyrrole in the solution A is 0.3 mol / L;

[0058] (2) stirring and dissolving 4,4-bipyridine in solution A to obtain solution B; the 4,4-bipyridine and step (1)

[0059] The solid-liquid ratio of pyrrole g:mL is 1:0.5;

[0060] (3) adding anhydrous FeCl3 to solution B, stirring and reacting at a temperature of 30°C for 2.5 hours to obtain solution C; the solid-liquid ratio of the anhydrous FeCl3 to the pyrrole in step (1) is 1:0.4 g:mL;

[0061] (4) placing solution C in a high pressure reactor, reacting at 95° C. for 52 h, cooling to room temperature, separating the solid and the liquid, soaking the solid in ethanol for 10 h, then washing with ethanol and deionized water in turn, and vacuum drying to obtain the silver ion organic adsorbent BPD-POP;

[0062] The selective adsorption performance of silver ions by the organic adsorbent BPD-POP of silver ions in this example is measured:

[0063] BPD-POP (10 mg) and a solution to be adsorbed (pH = 1, 10 mL) were added to a 15 mL centrifuge tube at room temperature, wherein the solution to be adsorbed contained 163.92 mg / L of Ag(I), 187.16 mg / L of Ca(II), 164.81 mg / L of Ni(II), 159.82 mg / L of Co(II), 150.35 mg / L of Al(III), and 132.6 mg / L of Mg(II); the mixture was shaken at 200 rpm for 20 h on an oscillator; the adsorbent was separated by centrifugation and the supernatant was obtained, and the residual concentration of the remaining metal ions in the supernatant was determined by ICP-OES;

[0064] The removal rates of Ag(I) were calculated to be 99.72%, Ca(II) to be 0.85%, Ni(II) to be 14.3%, Co(II) to be 2.86%, Al(III) to be 5.45%, and Mg(II) to be 11.73%.

[0065] It can be seen that the silver ion organic adsorbent BPD-POP of this embodiment has strong selectivity for silver ions;

[0066] Determination of the cyclic regeneration performance of the silver ion organic adsorbent BPD-POP in this example

[0067] The adsorbent was eluted with a desorbent (a desorption solution mixture consisting of 1% concentrated hydrochloric acid and 10% thiourea) and then centrifuged and washed with distilled water until the solution was neutral to complete the regeneration of the adsorbent BPD-POP. After 4 repeated experiments, the removal rate of Ag(I) in the fourth time was 79.55%.

[0068] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A silver ion organic adsorbent, characterized in that: The adsorbent is produced by the reaction of 4,4-bipyridine with pyrrole and dimethoxymethane, and is denoted as adsorbent BPD-POP, and its structural formula is: 。 2. The method for preparing the organic adsorbent for silver ions according to claim 1, characterized in that: The specific steps are as follows: (1) stirring and dissolving pyrrole and dimethoxymethane in N,N-dimethylformamide solvent to obtain solution A; (2) stirring and dissolving 4,4-bipyridine in solution A to obtain solution B; (3) Add anhydrous FeCl3 to solution B, stir and react at 30-50°C for 1-3 hours to obtain solution C; (4) Solution C is placed in a high pressure reactor and reacted at a temperature of 90-110°C for 45-55 hours. After cooling to room temperature, the solid and liquid are separated. The solid is soaked in ethanol for 6-24 hours, and then washed with ethanol and deionized water in sequence. The silver ion organic adsorbent is obtained by vacuum drying.

3. The method for preparing the organic adsorbent for silver ions according to claim 2, characterized in that: In step (1), the volume ratio of pyrrole to dimethoxymethane is 1:2.1-2.4, and the concentration of pyrrole in solution A is 0.1-0.3 mol / L.

4. The method for preparing the organic adsorbent for silver ions according to claim 2, characterized in that: The solid-liquid ratio g:mL of 4,4-bipyridine in step (2) to pyrrole in step (1) is 1:0.3-1.

5.

5. The method for preparing the organic adsorbent for silver ions according to claim 2, characterized in that: The solid-to-liquid ratio g:mL of the anhydrous FeCl3 in step (3) and the pyrrole in step (1) is 1:0.3-0.

8.

6. Use of the organic adsorbent for silver ions according to claim 1 in selectively adsorbing silver ions in a solution.

Images