One-dimensional benzimidazolone type COF material and preparation method and application thereof

Abstract

The invention discloses a one-dimensional benzimidazolone type COF material, and relates to the technical field of material chemistry, the COF material is prepared by Schiff base reaction of a benzimidazolone monomer and an aldehyde pyrene monomer; the preparation method comprises the following steps: uniformly mixing the benzimidazolone monomer and the aldehyde pyrene monomer, and adding a catalyst for catalytic reaction. According to the one-dimensional benzimidazolone COF and the preparation method thereof, by utilizing specific adsorption of double-arm amido bonds on a benzimidazolone group to gold, the prepared one-dimensional benzimidazolone COF can be used for rapidly and circularly recovering Au (III) from an aqueous solution with high selectivity and high capacity; besides, due to the fact that a large number of benzimidazolone groups and imine functional groups are fully exposed by the one-dimensional COF, Au (III) can be recycled in an ultra-fast and efficient mode, then the effect of selectively recycling gold from electronic waste liquid is achieved, and good application potential is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of material chemistry, and in particular to a one-dimensional benzimidazolone-type COF material and a preparation method and application thereof. Background Art

[0002] Gold is a rare and precious metal, widely used in high-tech fields such as electronics, communications, and aerospace. With the accelerated replacement of electronic products, electronic waste is increasing. Compared with the gold content in primary gold mines (about 30ppm), the gold content in electronic waste is much richer (about 2000ppm). Recycling the gold in these electronic wastes can effectively save the mining of primary gold mines and achieve sustainable utilization of resources. To date, many adsorbents, such as zeolites, nanoparticles, and carbon materials, have been widely studied for gold recovery. However, these materials have low adsorption capacity and poor recyclability. Therefore, it is crucial to develop materials with high capture efficiency and high adsorption capacity, good selectivity, and recyclability to recover gold from electronic waste.

[0003] Covalent organic frameworks (COFs) are composed of organic building blocks connected by covalent bonds. They have a designable porous network structure and a variety of topological configurations, making them ideal materials for efficient gold recovery. Currently, COFs adsorb gold mainly by modifying specific groups such as thiols, phenols, and amides on the porous walls to form hydrogen bond traps that capture gold. Compared with traditional two-dimensional (2D) or three-dimensional (3D) COFs, one-dimensional (1D) COFs have more in-plane sites and can significantly improve the efficiency of atomic utilization. However, due to the topological limitations of organic building blocks, it is difficult to introduce functional groups with specific adsorption effects on gold in 1D COFs, which to some extent hinders the development of 1D COFs in the field of gold adsorption.

[0004] Therefore, providing a one-dimensional benzimidazolone-type COF material with specific adsorption effect on gold is a technical problem that urgently needs to be solved in the field. Summary of the invention

[0005] In view of this, the present invention provides a one-dimensional benzimidazolone-type COF material and a preparation method and application thereof. The present invention utilizes the specific adsorption of gold by the double-armed amide bond on the benzimidazolone group, so that the prepared one-dimensional benzimidazolone-type COF can quickly, highly selectively and cyclically recover Au(III) from an aqueous solution in a large capacity; in addition, since the one-dimensional COF fully exposes a large number of benzimidazolone groups and imine functional groups, it can recover Au(III) ultra-fast and efficiently, thereby achieving the effect of selectively recovering gold from electronic waste liquid, and has good application potential.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A one-dimensional benzimidazolone type COF material is prepared by Schiff base reaction of benzimidazolone monomer and aldehyde pyrene monomer.

[0008] Preferably, the benzimidazolone monomer is 5,6-diaminobenzimidazolone, and the aldehyde pyrene monomer is 1,3,6,8-tetrakis(4-formaldehydephenyl)pyrene.

[0009] According to the above-mentioned method for preparing a one-dimensional benzimidazolone-type COF material, the method comprises the following steps: after the benzimidazolone monomer and the aldehyde pyrene monomer are uniformly mixed, a catalyst is added to catalyze the reaction.

[0010] Preferably, the molar ratio of the benzimidazolone monomer, the aldehyde pyrene monomer and the catalyst is 1:2:60-80.

[0011] Preferably, the molar ratio of the benzimidazolone monomer, the aldehyde pyrene monomer and the catalyst is 1:2:75.

[0012] Preferably, the catalyst is acetic acid.

[0013] Preferably, the concentration of the acetic acid is 4-12 mol / L.

[0014] Preferably, the catalytic reaction is carried out under vacuum conditions at 120-150° C. for 3-5 days.

[0015] Preferably, the catalytic reaction further comprises adding an organic solvent, and the amount of the organic solvent added is such that the concentration of the aldehyde pyrene monomer is 0.016-0.032 mmol / mL.

[0016] Preferably, the amount of the organic solvent added is such that the concentration of the aldehyde pyrene monomer is 0.016 mmol / mL.

[0017] Preferably, the organic solvent is a mixed solution of o-dichlorobenzene / n-butanol in a volume ratio of 1:1.

[0018] Preferably, the reaction system is further frozen, degassed and sealed before the catalytic reaction.

[0019] Preferably, after the catalytic reaction is completed, the obtained precipitate is washed and dried in sequence.

[0020] Preferably, the washing is carried out with ethanol, tetrahydrofuran and acetone in sequence.

[0021] Preferably, the drying is vacuum drying at 60° C. for 12 h.

[0022] Preferably, the regeneration method of the one-dimensional benzimidazolone-type COF material is: in 0.1 mol L -1 Thiourea and 0.1 mol L -1 Soak in a mixed solution of HCl for 8-12 hours.

[0023] Application of the one-dimensional benzimidazolone-type COF material described above or the one-dimensional benzimidazolone-type COF material prepared by the preparation method described above in gold ion adsorption.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The benzimidazolone group in the one-dimensional TFBI-COF of the present invention has a double-armed amide bond that specifically adsorbs gold and can quickly, highly selectively, and cyclically recover Au(III) from aqueous solution in a large capacity; at the same time, the mechanism of action between the benzimidazolone group in TFBI-COF and Au is revealed;

[0026] (2) The one-dimensional benzimidazolone-type TFBI-COF of the present invention has excellent chemical stability. The large number of benzimidazolone groups and imine functional groups on the surface give it a high affinity and strong reducing ability for Au(III), which can achieve selective and efficient enrichment of gold in complex environments;

[0027] (3) The one-dimensional benzimidazolone-type TFNBI-COF of the present invention can be used for the efficient recovery of Au(III) in solution, realizing the adsorption and recovery of Au(III) in electronic waste liquid, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings in this description are only embodiments of the present invention.

[0029] Figure 1 PXRD pattern of TFBI-COF in Example 1 of the present invention and PXRD result pattern of simulated AA and AB stacking models;

[0030] Figure 2 This is the SEM image of TFBI-COF of Example 1 of the present invention;

[0031] Figure 3 FTIR graph of TFBI-COF of Example 1 of the present invention;

[0032] Figure 4 This is the adsorption isotherm diagram of Au(III) by TFBI-COF in Application Example 1 of the present invention;

[0033] Figure 5 This is the adsorption kinetics diagram of Au(III) by TFBI-COF in Application Example 1 of the present invention;

[0034] Figure 6 This is the adsorption selectivity diagram of TFBI-COF to Au(III) in Application Example 1 of the present invention;

[0035] Figure 7 This is the cycle stability diagram of TFBI-COF to Au(III) in Application Example 1 of the present invention;

[0036] Figure 8 This is the adsorption selectivity diagram of TFBI-COF for Au(III) in electronic waste in Application Example 1 of the present invention. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention.

[0038] Example 1

[0039] The present invention provides a one-dimensional benzimidazolone-type TFBI-COF material, and the preparation method comprises the following specific steps:

[0040] A mixture of 1,3,6,8-tetrakis(4-formaldehydephenyl)pyrene TFPPy (18.56 mg, 3 μmol), 5,6-diaminobenzimidazolone DABI (9.8 mg, 6 μmol) and o-dichlorobenzene / n-butanol (1:1, 2.0 mL) was placed in a 15 mL heat-resistant glass tube, and after ultrasonic treatment for 15 min, 0.2 mL of acetic acid solution (6 M) was added, and then it was placed in a liquid nitrogen bath for rapid freezing, degassed by three freeze-pump-thaw cycles, and flame-sealed under vacuum;

[0041] After sealing, the temperature was raised to room temperature, and the sealed tube was placed in a 120°C oven for 3 days. After the reaction was completed, the generated precipitate was collected by filtration, washed with ethanol, tetrahydrofuran and acetone in sequence, and finally dried in vacuo at 60°C for 12 hours to obtain a bright yellow solid, which was a one-dimensional benzimidazolone-type TFBI-COF.

[0042] The crystal structure of TFBI-COF material was measured by powder X-ray diffractometer (PXRD). Figure 1As shown, the PXRD results show that TFBI-COF is a framework structure with high crystallinity. The diffraction peaks at 5.6°, 9.1° and 14.6° correspond to the 110, 220, 330 and 001 crystal planes of COF, respectively. The experimental PXRD results match the AA stacking theory PXRD spectrum exported by Materials Studio software, indicating the successful synthesis of TFBI-COF.

[0043] The morphology of the obtained TFBI-COF was characterized by scanning electron microscopy (SEM). Figure 2 As shown, TFBI-COF has a rod-like structure with a rough surface;

[0044] Fourier transform infrared spectroscopy (FTIR) was used to study the bonding of TFBI-COF. Figure 3 As shown in the figure, after the formation of COFs, the amino groups (-NH 2 ) stretching vibration peak (3364cm -1 ) and the stretching vibration peak of the aldehyde group (-CHO) in TFPPy (1686 cm -1 ) completely disappeared, and at 1628cm -1 The imine stretching vibration peak (C=N) appeared at , indicating that a Schiff base reaction occurred between DABI and TFPPy.

[0045] Application Examples

[0046] The TFBI-COF material prepared in Example 1 was applied to the adsorption recovery verification of Au(III), and the specific steps were as follows:

[0047] (1) Adsorption isotherm of TFBI-COF(III)

[0048] TFBI-COF (5 mg) was added to chloroauric acid solutions (10 mL) with initial concentrations of 50, 100, 200, 300, 400, 500, 750, 1000, and 1500 ppm, and then stirred at room temperature for 12 h. The mixture was filtered through a 0.22 μm microporous membrane, and the residual concentration of Au(III) in the filtrate was measured by inductively coupled plasma mass spectrometry. The adsorption capacity of TFBI-COF for Au(III) at equilibrium was calculated. e (mg g -1 ) by q e =(C o -C e ) / m×V, where q e (mg g -1 ) is the maximum adsorption capacity, C 0 (mg L -1 ) and C e(mg L -1 ) are the initial concentration and equilibrium concentration of gold ions, V(L) refers to the volume of the solution, and m(g) is the mass of the adsorbent. The experimental data were fitted using the Langmuir isotherm model: q e =q m B C e / (1+bC e ), where b is the Langmuir constant (L mg -1 ), C e is the equilibrium concentration of metal ions (mg L -1 ), q m is the monolayer adsorption capacity (mg g -1 ), q e is the equilibrium adsorption capacity (mg g -1 );

[0049] The results are as follows Figure 4 The adsorption capacity of TFBI-COF for Au(III) increases with the increase of Au(III) concentration until it reaches the adsorption equilibrium state. The maximum adsorption capacity of TFBI-COF for Au(III) is 2000 mg / g.

[0050] (2) Adsorption kinetics of Au(III) on TFBI-COF

[0051] TFBI-COF (5 mg) was dispersed in 10 mL chloroauric acid solution (300 ppm) for 0-180 min, filtered through a 0.22 μm microporous filter membrane, and the residual concentration of Au(III) in the filtrate at different times was measured by inductively coupled plasma mass spectrometry to calculate the adsorption capacity of TFBI-COF for Au(III) at that time. t (mg g -1 ) is calculated as: t =(C o -C t ) / m×V, where V is the volume of the solution (L), m is the mass of the adsorbent used (g), and C o and C t are the initial concentration of Au(III) and the concentration at a given time (mg L -1 ); The experimental data were fitted using a pseudo-second-order kinetic model: t / q t =1 / K 2 q e 2 +t / q e , where q t and q e represent the adsorption amount (mg g) at time t and at equilibrium (min), respectively. -1 ), K2 represents the pseudo-second-order rate constant (gmg -1 min -1 );

[0052] The results are as follows Figure 5 It can be seen that the gold recovery rate of TFBI-COF reached 98% within 30 minutes, which is better than other adsorbents reported previously.

[0053] (3) Adsorption selectivity of TFBI-COF for Au(III)

[0054] 5 mg of TFBI-COF was added to 10 mL of chloroauric acid aqueous solution containing 18 100 ppm mixed metal ions (Na(I), Mg(II), Al(III), K(I), Ca(II), V(V), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II), In(III), Hg(II), Pb(II)) to evaluate the adsorption selectivity for gold, and then stirred at room temperature for 1 h, filtered through a 0.22 μm microporous membrane, and the concentrations of various ions in the filtrate were measured by inductively coupled plasma mass spectrometry to calculate the adsorption amount of TFBI-COF for various ions. The adsorption amount (q) and recovery rate (recovery rate) of TFBI-COF for Au(III) were calculated by the formula q = (C o -C) / m×V, recovery rate=(C o -C) / C×100%, where q(mg g -1 ) is the amount of different metal ions adsorbed on TFBI-COF, C 0 (mg L -1 ) and C (mg L -1 ) are the initial concentration and residual concentration in aqueous solution, V(L) is the volume of solution, and m(g) is the mass of adsorbent;

[0055] The results are as follows Figure 6 , indicating that the material exhibits an ultra-high recovery effect only for Au(III).

[0056] (4) Recycling performance

[0057] At room temperature, TFBI-COF (40 mg) was suspended in Au(III) solution (80 mL, 100 ppm) and shaken at a constant speed. After reaching adsorption equilibrium, the remaining solution was filtered out to make the adsorbent at 0.1 mol L -1 Thiourea and 0.1 mol L -1The adsorption-desorption process was repeated 6 times, and the filtrate was measured by inductively coupled plasma mass spectrometry. The results are as follows: Figure 7 , indicating that the material exhibits high adsorption cycle stability for Au(III).

[0058] (5) Practical application in electronic waste liquid

[0059] Similar to the above adsorption experiment, TFBI-COF (5 mg) was suspended in the electronic waste leachate (10 mL), shaken for 12 h, and then the adsorbent was filtered out. The filtrate was collected and the residual concentration of each ion was determined by inductively coupled plasma mass spectrometry. The results are as follows: Figure 8 TFBI-COF can still be recycled efficiently in real electronic waste liquid.

[0060] It can be seen from the above that the TFBI-COF prepared by the method of the present invention has fast adsorption kinetics for Au(III) and shows excellent selectivity for Au(III), and can be used for the adsorption and recovery of Au(III) in electronic waste liquid.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A one-dimensional benzimidazolone-type COF material, characterized in that: The COF material is prepared by Schiff base reaction of benzimidazolone monomer and aldehyde pyrene monomer.

2. A one-dimensional benzimidazolone-type COF material according to claim 1, characterized in that: The benzimidazolone monomer is 5,6-diaminobenzimidazolone, and the aldehyde pyrene monomer is 1,3,6,8-tetrakis(4-formaldehyde phenyl)pyrene.

3. A method for preparing a one-dimensional benzimidazolone-type COF material according to any one of claims 1-2, characterized in that: The following steps are involved: After the benzimidazolone monomer and the aldehyde pyrene monomer are uniformly mixed, a catalyst is added to catalyze the reaction.

4. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 3, characterized in that: The molar ratio of the benzimidazolone monomer, the aldehyde pyrene monomer and the catalyst is 1:2:60-80.

5. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 3, characterized in that: The catalyst is acetic acid.

6. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 5, characterized in that: The concentration of the acetic acid is 4-12 mol / L.

7. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 3, characterized in that: The conditions of the catalytic reaction are: standing at 120-150° C. for 3-5 days under vacuum conditions.

8. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 3, characterized in that: The amount of the organic solvent added is such that the concentration of the aldehyde pyrene monomer is 0.016-0.032 mmol / mL; The organic solvent is a mixed solution of o-dichlorobenzene / n-butanol in a volume ratio of 1:

1.

9. The method for preparing a one-dimensional benzimidazolone-type COF material according to claim 3, characterized in that: The process also includes freezing, degassing and sealing the reaction system before the catalytic reaction.

10. Use of the one-dimensional benzimidazolone-type COF material according to any one of claims 1 to 2 or the one-dimensional benzimidazolone-type COF material prepared by the preparation method according to any one of claims 3 to 9 in gold ion adsorption.

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