CN108912338B

CN108912338B - Preparation of supramolecular organic framework and application of supramolecular organic framework in adsorption removal of pollutants in water body

Info

Publication number: CN108912338B
Application number: CN201810637744.2A
Authority: CN
Inventors: 林奇; 关晓文; 王姣; 樊彦青; 陈燕燕; 姚虹; 张有明; 魏太保
Original assignee: Northwest Normal University
Current assignee: Northwest Normal University
Priority date: 2018-06-20
Filing date: 2018-06-20
Publication date: 2020-10-16
Anticipated expiration: 2038-06-20
Also published as: CN108912338A

Abstract

The invention designs and synthesizes a column [5] arene supermolecule organic framework material SOFs-P5G based on naphthalimide functionalization, which is formed by self-assembling a main naphthalimide functionalized column [5] arene and a guest bis 4,4 bipyridine salt in an equimolar ratio in cyclohexanol. The supermolecule organic framework SOFS-P5G shows a very good adsorption removal effect on various organic pollutants in a water body. By monitoring with ultraviolet absorption spectrum, the removal rate of the SOFs-P5G to various pollutants is calculated to be more than 50%, wherein the removal rate to potassium permanganate reaches 99% at most. Adding the powder of the supermolecule organic framework material SOFs-P5G adsorbed with the pollutants into absolute ethyl alcohol, stirring for 15 minutes in a water bath at 35-40 ℃, releasing the adsorbed pollutants, filtering, and drying to enable the supermolecule organic framework material SOFs-P5G to achieve the purpose of recycling.

Description

Preparation of supramolecular organic framework and application of supramolecular organic framework in adsorption removal of pollutants in water body

Technical Field

The invention relates to a supermolecular organic framework SOFs-P5G which is formed by self-assembling a naphthalimide functionalized column [5] arene (P5N) serving as a main body and a bis-4, 4 bipyridyl salt (G) serving as an object, is mainly used for separating and removing pollutants in a water body, and belongs to the technical field of water treatment.

Background

The discharge of large amounts of dye waste water generated by the textile, leather, paper and printing industries has caused serious environmental problems over the last decades, since most commercial dyes are highly toxic and even carcinogenic by concentrating organisms. Many conventional physicochemical methods have been used to treat dye contamination. At present, among various treatment processes of dye-containing wastewater, an adsorption process has become one of the most useful technologies. Various adsorbents such as silica, clay, activated carbon and mesoporous silica have been used for such treatments. The use of adsorbent materials (e.g., activated carbon) for adsorbing organic pollutants in wastewater is an environmentally friendly method, but because of the long treatment time and high recovery cost, it is inefficient and costly for practical industrial applications, and is not convenient and fast for practical applications. Therefore, fast and efficient contaminant removal is a very challenging issue.

Disclosure of Invention

The invention aims to provide a preparation method of a supramolecular organic framework;

the invention also aims to provide the application of the supermolecular organic framework as an adsorbent in the adsorption removal of organic pollutants.

Preparation of mono-and supramolecular organic framework materials

The preparation of the supermolecular organic framework material is assembled by a column [5] arene (P5N) with a main body of naphthalimide functionalization and a

guest bis

4,4 bipyridyl salt (G) according to an equimolar ratio in cyclohexanol, and the column is marked as SOFs-P5G.

Wherein the structural formula of the main body naphthalimide functionalized column [5] arene (P5N) is as follows:

n=1、2、3、4；

the structure of guest bis 4,4 bipyridinium salt (G) is as follows:

the assembly mode of the subject and the object is as follows:

the mechanism of formation of the supramolecular polymer gel TDPG is analyzed by a nuclear magnetic map and a nuclear magnetic titration hydrogen spectrogram. FIG. 1 is a partial concentration nuclear magnetic map of P5N. In FIG. 1, the concentration of P5N gradually increases from (b) to (g), and H1-7 is found to move to a high field, which indicates that the column aromatic hydrocarbon group and the naphthalimide group of P5N have pi-pi action with another molecule P5N. FIG. 2 shows the NMR spectra of P5N and G. Wherein (a) P5N; (b) the (h) contains G in different equivalent weights. As can be seen from fig. 2, the hydrogen protons Ha, Hb, Hc, Hd and He on the guest G all shift to a low field, while the hydrogen protons H6 and H7 on the bulk of the pillared arene of host P5N shift to a high field, indicating that the pyridinium moiety of guest G enters the cavity of the pillared arene. The above phenomena can show that the host P5N and the guest G are assembled through host-guest recognition and pi-pi action, and the supramolecular organic framework material SOFS-P5G is obtained.

Second, the adsorption of supermolecule organic frame SOFS-P5G to various pollutants

Weighing pollutant compounds (such as methylene blue, golden orange, bismarck brown Y, Giardia dyeing agent, methyl orange, rhodamine B, Sudan Red 1, Sudan Red 2, picric acid, methyl naphthol, potassium permanganate and potassium dichromate) to be adsorbed in a beaker from a clean 50-mL volumetric flask with 12 bottles, adding 10mL of distilled water to completely dissolve the solid, transferring the solution into prepared colorimetric tubes, diluting the solution to 25mL scale with distilled water, and configuring the concentration to be 1 × 10^-3mol·L⁻¹The aqueous solution of (1) is ready for use.

50uL of the prepared various pollutant aqueous solutions (1.0 × 10) are respectively transferred^-3mol/L) is put into a 5mL reagent bottle, then distilled water is added to dilute the solution until the volume is 5mL, and the solution is shaken up to form the solution with the concentration of 1.0 × 10^-5And (3) standing the dilute solution of various pollutants in mol/L for later use.

Weighing 12 parts of the prepared supermolecular organic framework powder SOFS-P5G, wherein each part is 2 mg, and adding into the prepared powder with the concentration of 1.0×10^-5Stirring the solution for 40 minutes at room temperature in mol/L dilute solution of various pollutants, and standing. It was found that the color of the dilute solutions of each type of contaminant faded. FIG. 3 is a bar graph showing the removal efficiency of SOFs-P5G on 12 pollutants by adsorption (from left to right: methylene blue, golden orange, bismarck brown Y, Giardia's stainer, methyl orange, rhodamine B, Sudan Red 1, Sudan Red 2, picric acid, methylnaphthol, potassium permanganate, potassium dichromate). As can be seen from figure 3, the supramolecular organic framework SOFs-P5G powder prepared by the invention has good adsorption removal effect on pollutant methylene blue, golden orange, bismarck brown Y, Gilsberg stainer, methyl orange, rhodamine B, Sudan red 1, Sudan red 2, picric acid, methyl naphthol, potassium permanganate and potassium dichromate. The removal rate of various pollutants is calculated by monitoring with ultraviolet absorption spectrum. As a result, the removal rate of all pollutants is more than 50%, wherein the removal rate of potassium permanganate reaches up to 99%.

Desorption of three, supermolecular organic frameworks SOFS-P5G

Adding the supermolecule organic framework material SOFs-P5G powder adsorbed with the pollutants into absolute ethyl alcohol, and stirring in a water bath at 35-40 ℃ for 15 minutes to release the adsorbed pollutants; filtering and drying to make the supermolecular organic framework material SOFs-P5G reach the purpose of recycling. FIG. 4 is a bar graph showing the removal efficiency of supramolecular organic framework materials SOFs-P5G for methyl orange (a), rhodamine B (b), picric acid (c) and potassium permanganate (d) after multiple recycling. As can be seen from FIG. 4, the supramolecular organic framework material SOFs-P5G is desorbed and then used for adsorbing pollutants in water and still has high removal rate.

Fourth, the adsorption removal basic principle of SOFs-P5G on various pollutants

By taking methyl orange adsorption as an example, we have conducted a discussion of the adsorption mechanism. First we performed a nuclear magnetic titration experiment of methyl orange against SOFS-P5G (see FIG. 5). From FIG. 5 we can see that the peaks of hydrogen protons Ha, Hb, Hc and Hd on pyridinium are all shifted to high field and the hydrogen protons H1, H2, H3 and H4 on methyl orange are shifted to low field, indicating that there is electrostatic interaction between methyl orange and pyridinium in SOFs-P5G through anions and cations (see FIG. 3). Meanwhile, the demonstration is also carried out by two-dimensional nuclear magnetism, as shown in FIG. 6, four relevant points A, B, C and D are respectively the relevant points of hydrogen protons H6, H7 and H11 on the column aromatic hydrocarbon and the hydrogen protons H1, H2, H3 and H4 on the methyl orange, and the C-H-pi and pi-pi actions between the methyl orange and the column aromatic hydrocarbon are illustrated. According to the phenomena, a plurality of interaction forces (such as C-H-pi action, pi-pi action, electrostatic action of anions and cations and the like) exist in the process of removing various pollutants, so that the SOFs-P5G can be used for efficiently separating and removing various pollutants in an aqueous solution. The adsorption is formed by weak interaction force with various compounds, but the weak interaction force is easily destroyed, so that the adsorption can be used for desorbing and separating various pollutants to achieve the purpose of recycling the adsorption material, and the adsorption separation performance has important application value in the field of molecular removal.

Drawings

FIG. 1 is a nuclear magnetic hydrogen spectrum of P5N.

FIG. 2 shows the NMR spectra of P5N and G.

FIG. 3 is a bar graph showing the adsorption removal efficiency of SOFs-P5G on 12 pollutants.

FIG. 4 is a bar graph of the removal efficiency of supramolecular organic framework materials SOFs-P5G for (a) methyl orange, (B) rhodamine B, (c) picric acid, and (d) potassium permanganate in multiple recycling.

FIG. 5 is the NMR spectrum of methyl orange on SOFs-P5G.

FIG. 6 is a two-dimensional nuclear magnetic hydrogen spectrum of methyl orange and SOFs-P5G.

Detailed Description

The preparation of the supramolecular organic framework material SOFS-P5G and the performance of adsorbing organic pollutants in wastewater are further explained by specific examples.

Example 1 preparation of supramolecular organic framework materials SOFs-P5G

(1) Synthesis of host P5N to 50ml of acetonitrile was added 0.58g (5 × 10)^-3mol) brominated column [5]Aromatic P5, 0.43g (1.5 × 10)^-3mol) naphthalimide derivative, and reacting for 48h at 80 ℃; after the reaction is finished, cooling to room temperature, removing the solvent by rotary evaporation, mixing the sample with a column, eluting with petroleum ether and ethyl acetate =10: 1-10: 5 (v/v), and obtaining a yellow solid product, namely the gel factor P5N; the yield was 75.6%.

(2) Synthesis of guest G: 1.9801g (1.89 g, 6.3 mmol) of 1, 10-dibromodecane and 4,4' -bipyridine (5.56 g, 35.7 mmol) are added to 100ml of acetonitrile, and the mixture is stirred and refluxed at 90-100 ℃ for 18 hours; and cooling to room temperature, filtering by using a Buchner funnel, and washing for 3-5 times by using acetonitrile and ethanol to obtain 3.3G of pale yellow green powder product, namely guest compound G. The yield was 86%.

(3) Synthesis of supramolecular organic framework materials SOFS-P5G to 0.2ml of cyclohexanol was added host P5N (0.0050 g, 4.5 × 10^-6mol), guest G (0.0047G, 4.5 × 10^-6mol), heating to completely dissolve the materials, then cooling to room temperature, and drying to obtain the stable supramolecular organic framework material SOFs-P5G.

Example 2 efficient separation and removal of contaminants by supramolecular organic frameworks SOFS-P5G

The prepared concentration is 5mL 1 × 10^-5Aqueous solutions of various types of contaminants of M (methylene blue, golden orange, bismark brown Y, girl's stain, methyl orange, rhodamine B, sudan red 1, sudan red 2, picric acid, methyl naphthol, potassium permanganate, potassium dichromate); weighing 12 parts of powder of the supermolecule organic framework material SOFS-P5G, wherein each part is 2 mg, respectively adding the powder into the dilute solution of each pollutant, shaking for 40 minutes, standing, taking residual supernatant for ultraviolet spectrophotometry, and recording the absorbance. Then, the concentration of the residual solution is calculated according to the Lambert beer law, and the adsorption removal rate is calculated. The removal rates of the supramolecular organic frameworks SOFS-P5G for various pollutants are shown in Table 1:

example 3 Recycling of supramolecular organic frameworks SOFS-P5G

Filtering the water solution of the organic frame material SOFs-P5G powder adsorbed with various pollutants, and drying. And then respectively transferring the dry powder into 12 reagent bottles with 5 milliliters, adding 4 milliliters of absolute ethyl alcohol, and oscillating in a water bath with the temperature of 35 ℃ for 15 minutes to find that the color of the aqueous solution is changed into the color of various pollutants before adsorption, which indicates that the organic framework material SOFs-P5G releases various adsorbed pollutants. And then, filtering once, washing for 3-5 times by using ethanol, and drying to obtain the original organic framework material SOFs-P5G powder. Meanwhile, the reclaimed organic framework material powder SOFS-P5G can be recycled for multiple times.

Claims

1. A preparation method of supermolecular organic framework SOFs-P5G is characterized in that in cyclohexanol, a main body of naphthalimide functionalized column [5] arene and a guest of bis 4,4 bipyridyl salt are self-assembled according to an equimolar ratio;

the structural formula of the main body naphthalimide functionalized column [5] arene is as follows:

n=1、2、3、4；

the structural formula of the guest bis 4,4 bipyridine salt is as follows:

。

2. use of the supramolecular organic frameworks SOFs-P5G prepared by the method of claim 1 for adsorptive removal of contaminants in water.

3. Use of the supramolecular organic frameworks SOFs-P5G as claimed in claim 2 for the adsorptive removal of pollutants in water bodies, characterized in that: the contaminant is an organic dye.

4. Use of the supramolecular organic frameworks SOFs-P5G as claimed in claim 3 for the adsorptive removal of pollutants in water bodies, characterized in that: the organic dye is methylene blue, golden orange, bismarck brown Y, Gilford staining agent, methyl orange, rhodamine B, Sudan Red 1, Sudan Red 2.

5. Use of the supramolecular organic frameworks SOFs-P5G as claimed in claim 2 for the adsorptive removal of pollutants in water bodies, characterized in that: the pollutants are potassium permanganate and potassium dichromate.

6. Use of the supramolecular organic frameworks SOFs-P5G as claimed in claim 2 for the adsorptive removal of pollutants in water bodies, characterized in that: the pollutants are picric acid and methyl naphthol.

7. Use of the supramolecular organic frameworks SOFs-P5G as claimed in claim 2 for the adsorptive removal of pollutants in water bodies, characterized in that: adding the supermolecule organic framework material SOFs-P5G adsorbed with the pollutants into absolute ethyl alcohol, stirring in a water bath at 35-40 ℃, and releasing the pollutants, so that the supermolecule organic framework material SOFs-P5G is recycled.