CN113401967A

CN113401967A - Method for removing p-toluenesulfonic acid anions in aqueous solution

Info

Publication number: CN113401967A
Application number: CN202110310783.3A
Authority: CN
Inventors: 李生华; 庞思平; 李亚琼; 弥永胜; 彭盼盼
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-09-17

Abstract

The invention relates to a method for removing p-toluenesulfonic acid anions in an aqueous solution, belonging to the field of pollutant purification. The method comprises the following steps: let aTrz, Ts^‑And any other homologues in water to obtain a solution containing Ts^‑Adding Cu (NO)₃)₂Standing the solution at room temperature, filtering, washing and drying to obtain Ts^‑CMOFs as counter anions. Also provides a raw material recovery method: will be at Ts^‑Dissolving CMOFs as counter anion in water to obtain solution a, and reacting with NaNO₃Mixing the solutions, standing to obtain crystal, filtering, cleaning, drying, soaking the crystal in 100 deg.C water to dissolve to obtain aTrz and Cu (NO)₃)₂. The method is simple and is suitable for Ts^‑Has high selectivity, low cost, no pollution, suitability for industrial large-scale production, and capability of recovering raw materials to complete the processThe energy consumption of the individual reactions is low.

Description

Method for removing p-toluenesulfonic acid anions in aqueous solution

Technical Field

The invention relates to a method for removing p-toluenesulfonic acid anions in an aqueous solution, in particular to a method for efficiently separating the p-toluenesulfonic acid anions in the aqueous solution by constructing a cationic metal organic framework, and belongs to the field of pollutant purification.

Background

The separation of the target from the wastewater is a very important step in the wastewater treatment process. However, when a large number of analogues of the target are present in the wastewater, their structural and chemical properties are similar, making the separation of the target from the wastewater a significant challenge. P-toluenesulfonic acid anion is an organic anion pollutant in wastewater, and when organic anions with similar structures exist in wastewater, like anions of a system, the separation of p-toluenesulfonic acid anion from wastewater becomes a troublesome problem.

The use of porous materials with different pore sizes and shapes to separate complex mixtures is one of the most common methods. In the past decades, a large number of porous materials, including porous organic polymers, hydrogen-bonded organic frameworks (hnfs), Covalent Organic Frameworks (COFs), Metal Organic Frameworks (MOFs), etc., have been developed for the separation of light alkanes of similar structure and performance, and have achieved desirable results.

However, the application of these materials to the separation of target substances from wastewater has been less studied, mainly for the following reasons: 1) when competing analogs are present, the separation performance of these materials is greatly reduced, especially when the size of the analog of the target in the aqueous solution is smaller than the target, making separation more difficult; 2) some porous materials, such as MOFs and COFs, have poor stability in water, are easily decomposed, and cannot be used for separation.

As one type of MOFs, Cationic Metal Organic Frameworks (CMOFs) form a framework from neutral ligands and metal ions or metal clusters by self-assembly, while anions are adsorbed in the channels as charge-balancing ions (exist freely without coordination to the metal). Based on the structural characteristics of CMOFs, it has been shown that the thermodynamic controlled crystallization method is used to construct CMOFs from 4, 4' -azo-1, 2,4-triazole to separate the Organic contaminants, 2,4, 6-trinitrophenol anions (ZHao C, Du Y, Zhang, J et al. high purity effluent Separation of the Anionic Organic polar from Water Structure of Functional Organic metallic Frameworks and mechanical Study, ACS. Material. interfaces,2020,12, 22835), from Water, however, this document does not give a method for isolating the analogue and the p-toluenesulphonic acid anion is very different from the 2,4, 6-trinitrophenol anion in the document, and therefore, when p-toluenesulfonic acid anion and any other analogue (such as a system) are present in the aqueous solution at the same time, how to effectively separate the water-soluble organic acid from the aqueous solution is a technical problem to be solved.

Disclosure of Invention

In view of the above, it is an object of the present invention to provide a method for removing p-toluenesulfonate anion in an aqueous solution by using 4, 4' -azo-1, 2,4-triazole as a neutral ligand, copper ion and p-toluenesulfonate anion (Ts) to be separated in combination with a thermodynamically and kinetically controlled crystallization method^-) To construct highly stable, rapidly crystallizing CMOFs, i.e. with Ts^-CMOFs are constructed as counter anions, thereby achieving the purpose of removing p-toluenesulfonic acid anions from water.

In order to achieve the purpose of the invention, the following technical scheme is provided.

A method for removing p-toluenesulfonic acid anions in an aqueous solution, comprising the following steps:

(1) configuration containing Ts^-The solution (2): a neutral ligand, 4' -azo-1, 2,4 triazole (aTrz, the molecular formula is C)₄H₄N₈)、Ts^-And the anion of any of the other homologs dissolved in water.

(2) To contain Ts^-Adding Cu (NO) to the solution₃)₂Standing the solution at room temperature for more than 24h, filtering to obtain solid product, washing, and drying to obtain Ts^-CMOFs as counter anions.

WhereinaTrz and Ts^-The ratio of the amounts of the substances is greater than or equal to 1: 1; the ratio of the aTrz to the amount of copper ion species is 2:1 or less.

Preferably, aTrz and Ts^-The ratio of the amounts of the substances of (a) to (b) is 1: 1; the ratio of the amount of species of aTrz to copper ions was 2: 1.

Preferably, Ts^-The ratio of the amount of the substance to the anion of any of the other homologues is 1:1 or more.

More preferably, Ts^-The mass ratio of the anion to any of the other homologues is 1: 1.

Preferably, the anion of any of the other homologs is the benzenesulfonic acid anion (Bs)^-) Ethyl benzene sulfonic acid anion (Es)^-) Or isopropylbenzene sulfonic acid anion (Ps)^-)。

Preferably, in the step (2), the mixture is allowed to stand at room temperature for 24 hours.

The above method is carried out by reacting with Ts^-Construction of CMOFs as counter anions to achieve separation of Ts from aqueous solution^-And anions of any of the other homologues, for Ts^-Has good selectivity.

In addition, Ts is the number of molecules obtained by the method of the invention^-The invention also provides for the production of starting materials, namely aTrz and Cu (NO), as counter-anionic CMOFs₃)₂The recycling method of (1), wherein the recycling method comprises:

will be at Ts^-Dissolving CMOFs as counter anion in water to obtain solution a, and mixing the solution a with NaNO₃Mixing the solution uniformly, standing for over 72h, and performing ion exchange to obtain new crystal, i.e. NO₃ ^-Filtering CMOFs as counter anion to obtain filtrate containing sodium p-toluenesulfonate, washing the crystal obtained by filtering, drying, soaking the crystal in 100 deg.C water to dissolve to obtain aTrz and Cu (NO)₃)₂Thereby achieving the purpose of recovering the raw materials.

Wherein, NaNO₃NaNO in solution₃Is Ts in the solution a^-The concentration of the CMOFs as the counter anion is 5 times or more.

Preferably, NaNO₃NaNO in solution₃Is Ts in the solution a^-5 times the concentration of CMOFs as counter anion.

Preferably, solution a is mixed with NaNO₃The solution is mixed evenly and kept stand for 72 h.

Advantageous effects

(1) The invention provides a method for removing p-toluenesulfonic acid anions in aqueous solution, which is implemented by reacting Ts with a catalyst^-Construction of CMOFs as counter anions to achieve separation of Ts from aqueous solution^-The method has the advantages of simple operation process, low cost, greenness, no pollution and suitability for industrial large-scale production.

(2) The invention provides a method for removing p-toluenesulfonic acid anions in aqueous solution, although anions of any other homolog, such as Bs, exist in the aqueous solution^-，Es^-Or Ps^-The method of the invention takes aTrz as a neutral ligand, and the aTrz and copper ions form a framework material, and the pore size of the framework material is favorable for adsorbing Ts^-To Ts^-Has stable effect and high selectivity, and forms Ts^-CMOFs as counter anions; so when the aqueous solution contains Ts^-And anions of any of the other homologs, Ts is treated by the methods of the invention^-The selectivity of (A) can be as high as 100%.

(3) According to the method for removing p-toluenesulfonic acid anions in the aqueous solution, provided by the invention, the raw materials can be recovered by an ion exchange method, so that the energy consumption of the whole reaction is low.

Drawings

FIG. 1 is a nuclear magnetic hydrogen spectrum of the final products obtained in example 1, example 2 and example 3, and CMOFs (Ts) -RT, CMOFs (Es) -RT and CMOFs (Bs) -RT.

FIG. 2 is a partially enlarged nuclear magnetic hydrogen spectrum of the final products obtained in example 1, example 2 and example 3 and CMOFs (Ts) -RT, CMOFs (Es) -RT and CMOFs (Bs) -RT.

Detailed Description

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the following examples:

the 4, 4' -azo-1, 2,4-triazole (aTrz) is prepared according to the method described in the document "Li S H, Pang S P, Li X T, et al Synthesis of new tetrazene (N-N ═ N-N) -linked bi (1,2,4-triazole) [ J ]. Chinese Rapid chemical letters, 2007, 18(10): 1176-1178", and the detailed steps are as follows:

dissolving 15ml of glacial acetic acid in 80ml of deionized water, pouring into a three-mouth bottle, and cooling to 5-7 ℃ for later use. Weighing 10.56g of sodium hypochlorite, adding the sodium hypochlorite into the three-mouth bottle, and reacting the sodium hypochlorite and the three-mouth bottle at room temperature for 6 hours; then 4g of 4-amino-1, 2,4-triazole was weighed out and dissolved in 10mL of water, and the solution was added to the three-necked flask, and the stirring speed was controlled to 700 r.min^-1. After the addition of 4-amino-1, 2,4-triazole was completed, the reaction was carried out at room temperature for 1 hour, and then the obtained white precipitate was filtered and recrystallized in deionized water to obtain the product aTrz used in this example.

CMOFs (Ts) -RT, CMOFs (Bs) -RT and CMOFs (Es) -RT, respectively^-Or Bs^-Or Es^-CMOFs, synthesized directly as counter anions, are standard samples; the preparation method of CMOFs (Ts) -RT is as follows:

(1) 0.25mmol of aTrz and 0.25mmol of sodium p-toluenesulfonate are added into 5ml of deionized water, the mixture is magnetically stirred for 10min at 80 ℃ to ensure that the sample is completely dissolved, and the mixture is cooled to room temperature for standby.

(2) 0.125mmol of Cu (NO)₃)₂Dissolving in 5mL deionized water to obtain Cu (NO)₃)₂And (3) solution. Adding Cu (NO)₃)₂The solution is dripped into a solution containing Ts^-The solution of (1) is kept stand for 24h at room temperature, filtered to obtain blue crystals, the blue crystals are washed with deionized water and methanol for three times in sequence, and dried for 24h at room temperature to obtain the blue crystals with Ts^-The CMOFs as counter anions are standard samples, i.e., CMOFs (Ts) -RT.

Preparation methods of CMOFs (Bs) -RT and CMOFs (Es) -RT: replacing the sodium p-toluenesulfonate in the step (1) with sodium benzenesulfonate or sodium ethylbenzenesulfonate, and the rest is the same as the preparation method of CMOFs (Ts) -RT.

Example 1

(1) Configuration containing Ts^-The solution (2): 0.25mmol of aTrz, 0.25mmol of NaTs and 0.25mmol of NaBs are added into 5ml of deionized water, and the mixture is magnetically stirred for 10min at 80 ℃ to ensure that the sample is completely dissolved and cooled to room temperature for later use.

(2) 0.125mmol of Cu (NO)₃)₂Dissolving in 5mL deionized water to obtain Cu (NO)₃)₂And (3) solution. Adding Cu (NO)₃)₂The solution is dripped into a solution containing Ts^-The solution is kept still for 24 hours at room temperature, filtered to obtain blue crystals, the blue crystals are washed for three times by deionized water and methanol in sequence, and dried for 24 hours at room temperature to obtain the final product.

The final product obtained in this example had the same shape and color as CMOFs (Ts) -RT.

The end product obtained in this example was subjected to nuclear magnetic hydrogen spectroscopy and the results are shown as Ts in FIG. 1^-/Bs^-CMOFs (Ts) -RT and CMOFs (Bs) -RT, it can be seen that the final product (Ts) obtained in this example is comparable to the CMOFs (Ts) -RT hydrogen spectra^-/Bs^-Test results of (1) shows a methyl peak, which is identical to the results of CMOFs (Ts) -RT, indicating that Ts is present in the final product^-(ii) a Compared with the hydrogen spectrum results of CMOFs (Bs) -RT, the specific results are shown in FIG. 2, the hydrogen spectrum of the final product prepared in the embodiment has the hydrogen atom displacement of 7.0-8.0, which is inconsistent with the hydrogen atom displacement of CMOFs (Bs) -RT; the difference in the integrated areas of the hydrogen atoms indicates that the final product of this example has a different number of hydrogen atoms from the CMOFs (Bs) -RT, and that the final product does not contain Bs^-Thus, the final product obtained in this example is Ts^-CMOF as counter anion, without Bs^-That is, the present embodiment is applied to Ts in the process of constructing CMOFs^-The selectivity of (A) is up to 100%.

To recover the starting material, Ts prepared in this example was taken^-Adding CMOFs100mg as counter anions into 10mL of deionized water, and stirring at 80 ℃ to dissolve the CMOFs in the deionized water to obtain a solution a; wherein Ts is added into the solution a^-The concentration of CMOFs as counter anions was 0.012 mmol/mL; then 51mg NaNO₃Dissolving in 10mL deionized water to obtain NaNO₃NaNO with concentration of 0.06mmol/mL₃A solution; mixing the solution a with NaNO₃Mixing the solution uniformly, standing for 72h, filtering to obtain a new blue crystal, washing the filtered blue crystal with methanol, drying at room temperature for 24h, and soaking the blue crystal in 100 deg.C water to dissolve to obtain aTrz and Cu (NO)₃)₂Thereby achieving the purpose of recovering raw materials.

During the recovery process, the new blue crystal obtained is subjected to single crystal diffraction test, and the test result is completely the same as the crystal structure of CCDC No. 955533, and the crystal of CCDC No. 955533 is NO₃ ^-CMOFs as counter anions, i.e. NO as novel blue crystals₃ ^-The blue crystals dissolved in water as the counter anion CMOFs gave the starting materials used in this example, aTrz and Cu (NO)₃)₂。

Example 2

(1) Configuration containing Ts^-The solution (2): adding 0.25mmol of aTrz, 0.25mmol of NaTs and 0.25mmol of NaEs into 5mL of deionized water, magnetically stirring at 80 ℃ for 10min to ensure that the sample is completely dissolved, and cooling to room temperature for later use.

Prepared by the present exampleThe final product was subjected to nuclear magnetic hydrogen spectroscopy, and the results are shown as Ts in FIG. 1^-/Es^-CMOFs (Ts) -RT and CMOFs (Es) -RT, it can be seen that the final product (Ts) obtained in this example is comparable to the hydrogen spectra of CMOFs (Ts) -RT^-/Es^-Test results of (1) shows a methyl peak, which is identical to the results of CMOFs (Ts) -RT, indicating that Ts is present in the final product^-(ii) a Compared with the hydrogen spectrum result of CMOFs (Es) -RT, the final product prepared in the embodiment has no ethyl peak, and shows that the final product only contains Ts^-Does not contain Es^-Further, the final product obtained in this example is Ts^-CMOFs as counterions, i.e. for Ts in the construction of CMOFs in this example^-The selectivity of (A) is up to 100%.

The raw materials used in this example, aTrz, Cu (NO)₃)₂The recovery method of (3) is the same as in example 1.

Example 3

(1) Configuration containing Ts^-The solution (2): adding 0.25mmol aTrz, 0.25mmol NaTs and 0.25mmol NaPs into 5mL deionized water, magnetically stirring at 80 ℃ for 10min to ensure that the sample is completely dissolved, and cooling to room temperature for later use.

The end product obtained in this example was subjected to nuclear magnetic hydrogen spectroscopy and the results are shown as Ts in FIG. 1^-/Ps^-And CMOFs (Ts) -RT, it can be seen that the final product (Ts) obtained in this example is compared with the hydrogen spectra of CMOFs (Ts) -RT^-/Ps^-Test results) shows only a methyl group peak, and results of CMOFs (Ts) -RTThe same is true, and no other peak appears, indicating that Ts is present in the final product^-Does not contain Ps^-Further, the final product obtained in this example is Ts^-CMOFs as counterions, i.e. for Ts in the construction of CMOFs in this example^-The selectivity of (A) is up to 100%.

The present invention includes, but is not limited to, the above embodiments, and any equivalent substitutions or partial modifications made under the principle of the spirit of the present invention should be considered as being within the scope of the present invention.

Claims

1. A method for removing p-toluenesulfonic acid anions in an aqueous solution is characterized by comprising the following steps: the method comprises the following steps:

(1) configuration containing Ts^-The solution (2): let aTrz, Ts^-And anions of any of the other homologues, dissolved in water;

(2) to contain Ts^-Adding Cu (NO) to the solution₃)₂Standing the solution at room temperature for more than 24h, filtering to obtain solid product, washing, and drying to obtain Ts^-CMOFs as counter anions;

wherein, aTrz and Ts^-The ratio of the amounts of the substances is greater than or equal to 1: 1; the ratio of the aTrz to the amount of copper ion species is 2:1 or less.

2. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 1, wherein: aTrz and Ts^-The ratio of the amounts of the substances of (a) to (b) is 1: 1; the ratio of the amount of species of aTrz to copper ions was 2: 1.

3. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 1, wherein: ts^-The ratio of the amount of the substance to the anion of any of the other homologues is 1:1 or more.

4. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 3, wherein: ts^-The mass ratio of the anion to any of the other homologues is 1: 1.

5. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 1, wherein: the anion of any other homologue is Bs^-、Es^-Or Ps^-。

6. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 1, wherein: and (3) standing for 24 hours at room temperature in the step (2).

7. The method for removing p-toluenesulfonic acid anion in aqueous solution according to claim 1, wherein: aTrz and Ts^-The ratio of the amounts of the substances of (a) to (b) is 1: 1; the mass ratio of aTrz to copper ions is 2: 1;

Ts^-the ratio of the amount of material to the anion of any of the other homologs is 1: 1;

the anion of any other homologue is benzene sulfonic acid anion, ethyl benzene sulfonic acid anion or isopropyl benzene sulfonic acid anion;

and (3) standing for 24 hours at room temperature in the step (2).

8. Raw materials aTrz and Cu (NO)₃)₂The method for recycling (2), characterized in that: ts prepared by the method for removing p-toluenesulfonic acid anion in aqueous solution according to any one of claims 1 to 7^-Dissolving CMOFs as counter anion in water to obtain solution a, and mixing the solution a with NaNO₃Mixing the solution uniformly, standing for over 72h to obtain new crystal, i.e. NO₃ ^-CMOFs as counter anion, filtering to obtain filtrate containing sodium p-toluenesulfonate, washing the filtered crystal, drying, soaking in 100 deg.C water to dissolve to obtain aTrz andCu(NO₃)₂；

9. The starting materials aTrz and Cu (NO) according to claim 8₃)₂The method for recycling (2), characterized in that: NaNO₃NaNO in solution₃Is Ts in the solution a^-5 times the concentration of CMOFs as counter anion.

10. The starting materials aTrz and Cu (NO) according to claim 9₃)₂The method for recycling (2), characterized in that: mixing the solution a with NaNO₃The solution is mixed evenly and kept stand for 72 h.