CN114225913A

CN114225913A - Efficient preparation method of UiO-66 and adsorption of UiO-66 on cationic dye

Info

Publication number: CN114225913A
Application number: CN202210000764.5A
Authority: CN
Inventors: 刘秀明; 卢雪; 房宽峻
Original assignee: Tianjin Polytechnic University
Current assignee: Tianjin Polytechnic University
Priority date: 2022-01-05
Filing date: 2022-01-05
Publication date: 2022-03-25

Abstract

The invention relates to a high-efficiency preparation method of UiO-66 and research application thereof in the field of adsorption of cationic dyes. Obtaining an efficient UiO-66 preparation method. Compared with other MOFs materials, the preparation method of the UiO-66 adopts a one-bath method, has simple production flow, low raw material cost and convenient operation, reduces the production cost and saves the energy consumption. The removal rate of the cationic dye is high, and the method has research significance in the field of colored wastewater treatment.

Description

Efficient preparation method of UiO-66 and adsorption of UiO-66 on cationic dye

Technical Field

The invention relates to the field of environmental protection, in particular to a high-efficiency preparation method of UiO-66 and adsorption of the UiO-66 on cationic dye.

Background

In recent years, with the continuous development of science and technology and society, the industrialization process of the textile industry meets the daily life requirements of people, and meanwhile, the requirement on the environment is continuously improved. Wherein, the wastewater generated in industrial production causes great water body pollution due to imperfect treatment, and does not conform to the green environmental protection idea advocated by the current society. In the production process of textile products, a large amount of water is needed to dye, print and the like textiles, so that the treatment of dye wastewater becomes particularly important. If the dye wastewater is not treated in a proper way and discharged into rivers, the problem of great environmental pollution can be caused, and toxic and harmful substances in the dye wastewater can threaten animals and plants in the rivers.

The cationic dye is a special dye for acrylic fibers, has the characteristics of bright color and good water solubility, and is one of the earliest synthetic dyes. The cationic dye wastewater contains various substances and has the characteristics of complex composition structure, high salinity, low pH value, poor biodegradability and the like. After untreated cationic dye wastewater enters a natural water body, the water body balance can be damaged, so that the aquatic plants cannot carry out photosynthesis, and the growth of aquatic animals is hindered. The method for treating the cationic dye wastewater mainly comprises a physical method, a chemical method and a biological method. The physical method is mainly used for separating or removing the cationic dye in the dye wastewater through physical action. The physical method is convenient for recovering dye molecules from the wastewater, reduces the content of salt and metal ions in the cationic dye wastewater, and improves the biodegradability. Therefore, when dye wastewater is treated, the pretreatment is usually carried out by a physical method regardless of whether the treatment is carried out by a chemical method or a biological method. The chemical method treats the cationic dye wastewater by causing the pollutants to generate chemical reaction, can change the structure of the pollutants, fundamentally solves the problem of cationic dye pollution, and has good treatment effect, so the chemical method is widely applied, and the chemical method for treating the cationic dye wastewater mainly comprises a flocculation method, a chemical oxidation method, a photocatalytic oxidation method and the like. The biological method is to separate or degrade cationic dye molecules through the flocculation, adsorption and degradation of microorganisms, so as to remove the pollution of the cationic dye wastewater. At present, biological methods are widely applied to the treatment of cationic dye wastewater at home and abroad. The biological method mainly comprises an aerobic method and an anaerobic method. Since the 70 s of the 20 th century, China has been primarily treating dye wastewater by a biological method, most of which are aerobic methods. In the practical application process, the anaerobic method has very obvious effect on the decolorization of the cationic dye wastewater. However, after decolorization by anaerobic method, cationic dyes are mostly reduced to amine compounds under the action of microorganisms. The amine compounds have large toxic action on microorganisms, and organic matters in the wastewater cannot be completely removed, so that the COD value of the effluent is large. In contrast, combined aerobic and anaerobic treatment will eventually lead to aminesRing opening mineralization of compounds to CO₂And the COD value is greatly reduced in the process. Therefore, the strengthened aerobic and anaerobic combined treatment method can realize the final mineralization of the pollutants, thereby realizing the detoxification treatment and achieving the purpose of removing the pollutants. The adsorption method is a common treatment mode of dye wastewater, but the traditional adsorption material has the defects of smaller adsorption quantity, lower adsorption rate and high selectivity, and the wide application of the adsorption material in colored wastewater treatment is limited. Currently, MOFs materials are gaining popularity as a porous adsorbent material, which has a large specific surface area and a high porosity, and has an adjustable structure. In addition, most MOFs have a problem that stability in water and a good adsorption effect cannot coexist.

Based on this, UiO-66 is selected as the dye adsorbent, compared with other MOF materials, UiO-66 has extremely strong stability in water, excellent thermal stability and obvious tolerance to pH value, and the problem of the coexistence of the MOF materials and adsorption effect can be solved. The most efficient synthetic method of UiO-66 is obtained by changing the synthetic conditions. The UiO-66 synthesized by the synthesis method has strong stability and reduced cost, and has certain theoretical guidance significance for printing and dyeing wastewater treatment, water body environment and soil treatment in the textile industry.

Disclosure of Invention

In order to improve the removal efficiency of cationic dye in printing and dyeing wastewater, the stability of the adsorbent and the high efficiency of the synthetic adsorbent, the method comprises the steps of putting zirconium chloride, terephthalic acid, an organic solvent and a pH regulator into a round-bottomed flask, heating in a water bath, stirring, washing and airing. The most efficient synthesis process is determined by changing synthesis conditions, and is used for adsorbing the cationic dye, so that the cationic dye achieves a good adsorption effect, the adsorption rate can also reach more than 90 percent, and the method is also greatly improved in practical application.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the first step is as follows: dissolving zirconium chloride in a mixed solution of an organic solvent and a pH regulator to obtain a metal precursor solution, and performing ultrasonic action.

The second step is that: terephthalic acid is mixed with an organic solvent to obtain another mixed solution.

The third step: mixing the first step and the solution obtained in the second step, and heating and reacting in a closed container.

The fourth step: the resulting product is washed in an organic solvent.

Preferably, the method for efficiently preparing the UiO-66 is characterized in that the molar ratio of the zirconium chloride to the terephthalic acid in the first step and the second step is 1: 1-1: 2, the organic solvent is N, N-dimethylformamide or methanol, and the pH regulator is concentrated hydrochloric acid.

Preferably, the efficient preparation method of the UiO-66 is characterized by comprising the following components, by mass, 0.2% -2% of zirconium chloride, 0.2% -2% of terephthalic acid, 2% -15% of concentrated hydrochloric acid and the balance of DMF, and performing ultrasonic action for 5-20 min.

Preferably, the method for efficiently producing UiO-66 is characterized in that the heating form in the third step is oven heating or water bath heating.

Preferably, the efficient preparation method of UiO-66 is characterized in that the heating temperature in the third step is 60-120 ℃.

Preferably, the method for efficiently producing UiO-66 is characterized in that the reaction conditions in the third step are stirred at a rate of 0 to 200 r/min.

The beneficial effect that adopts foretell technical scheme to produce lies in:

(1) the UiO-66 adopted by the invention has stable structure, is not easy to be damaged, has stable performance in extreme acid, extreme alkali and various organic solvents, has low raw material cost, simple process operation and high efficiency, shortens the reaction time and reduces the energy consumption.

(2) The invention solves the problem of water pollution caused by cationic dye in printing and dyeing wastewater, has good adsorption effect and reduces pollutant discharge.

Drawings

FIG. 1: effect of time on the adsorption quantity of cationic blue adsorbed by UIO-66

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

EXAMPLE 1 preparation of UiO-66 at different temperatures

Dissolving zirconium chloride (1510mg, 6.48mmol) in a mixed solution of 60mLDMF and 12mL concentrated hydrochloric acid, and performing ultrasonic action for 10min to obtain a metal precursor solution; dissolving terephthalic acid (1495mg, 9mmol) in 120mLDMF in a separate beaker, adding into the precursor solution, mixing uniformly, heating to 60 ℃, 80 ℃, 100 ℃, 120 ℃ and 140 ℃ in water bath respectively, reacting for 12h, washing 3 times with DMF and methanol solution respectively after the reaction is finished, and finally vacuum drying for 24 h. There were obtained 5 UiO-66 preparations at different temperatures, and these 5 UiO-66 preparations were then characterized. The results are shown in Table 1.

TABLE 1 specific surface area for the preparation of UiO-66 at different temperatures

EXAMPLE 2 preparation of UiO-66 with different molar ratios of zirconium chloride to terephthalic acid

Dissolving zirconium chloride in a mixed solution of 60mLDMF and 12mL concentrated hydrochloric acid, and performing ultrasonic action for 10min to obtain a metal precursor solution; dissolving terephthalic acid in 120mLDMF in a separate beaker, adding the solution into the precursor solution, uniformly mixing, heating in a water bath to 80 ℃ for reaction for 12h, washing 3 times by DMF and methanol solutions respectively after the reaction is finished, and finally drying in vacuum for 24 h. The molar ratio of zirconium chloride to terephthalic acid is 1: 1, 1: 1.5 and 1: 2 respectively. 3 prepared UiO-66 were obtained in different molar ratios, and then the 3 UiO-66 were characterized. The results are shown in Table 2.

TABLE 2 specific surface area for the preparation of UiO-66 at different molar ratios

EXAMPLE 3 preparation of UiO-66 with different heating regimes

Dissolving zirconium chloride (1510mg, 6.48mmol) in a mixed solution of 60mLDMF and 12mL concentrated hydrochloric acid, and performing ultrasonic action for 10min to obtain a metal precursor solution; in a separate beaker, terephthalic acid (1495mg, 9mmol) was dissolved in 120ml DMF, added to the precursor solution, mixed well, heated to 80 ℃ for reaction for 12h, washed 3 times with DMF and methanol solution after the reaction, and finally vacuum dried for 24 h. The heating mode is water bath heating and oven heating. 2 different heating methods of preparation of UiO-66 were obtained, and then the two kinds of UiO-66 were characterized. The results are shown in Table 3.

TABLE 3 specific surface area for UiO-66 preparation under different heating regimes

EXAMPLE 4 preparation of UiO-66 at different agitation rates

Dissolving zirconium chloride (1510mg, 6.48mmol) in a mixed solution of 60mLDMF and 12mL concentrated hydrochloric acid, and performing ultrasonic action for 10min to obtain a metal precursor solution; in a separate beaker, terephthalic acid (1495mg, 9mmol) is dissolved in 120ml DMF, added into the precursor solution and mixed evenly, heated in a water bath to 80 ℃ for reaction for 12h, washed 3 times by DMF and methanol solution respectively after the reaction is finished, and finally dried in vacuum for 24 h. The rotation speed during the reaction is 0, 50, 100, 150 and 200 r/min. The prepared UiO-66 was obtained at 5 different rotational speeds, and then the 5 UiO-66 were characterized. The results are shown in Table 4.

TABLE 4 specific surface area for UiO-66 preparation at different agitation rates

EXAMPLE 5 Effect of time on UiO-66 adsorption of cationic blue

Preparing 100mL of cationic blue dye solution with the concentration of 60mg/L into a conical flask, weighing 50mg of UiO-66 powder, putting into the conical flask, oscillating and adsorbing at room temperature at the rotating speed of 200r/min every 10min, 20min, 30min, 40min, 60min, 90min, 120min, 150min and 180min, and measuring the absorbance and calculating the adsorption capacity by analogy.

As shown in FIG. 1, according to the trend analysis of the change of the adsorption amount with time, the UIO-66 powder reaches the adsorption equilibrium within 6 hours, the maximum adsorption amount is 100mg/g, the removal rate reaches 90%, and the powder has a high adsorption rate on the cation blue and has a good adsorption effect.

Claims

1. An efficient preparation method of UiO-66 is characterized by comprising the following specific steps:

the first step is as follows: dissolving zirconium chloride in a mixed solution of an organic solvent and a pH regulator to obtain a metal precursor solution, and carrying out ultrasonic treatment.

The fourth step: the resulting product is washed in an organic solvent.

2. The process of claim 1, wherein the molar ratio of zirconium chloride to terephthalic acid in the first and second steps is 1: 1 to 1: 2, the organic solvent is N, N-dimethylformamide or methanol, and the pH regulator is concentrated hydrochloric acid.

3. The efficient preparation method of UiO-66 according to claim 2, characterized by comprising, by mass, 0.2% -2% of zirconium chloride, 0.2% -2% of terephthalic acid, 2% -15% of concentrated hydrochloric acid, and the balance of DMF, and subjecting to ultrasonic treatment for 5-20 min.

4. The efficient preparation method of UiO-66 as claimed in claim 1, wherein the heating form in the third step is oven heating or water bath heating.

5. The efficient process of claim 1, wherein the heating temperature in the third step is 60-120 ℃.

6. The process for producing UiO-66 of claim 1, wherein the reaction conditions in the third step are stirred at a rate of 0 to 200 r/min.

7. The application of UiO-66 in adsorbing cationic dye is characterized in that UiO-66 powder can adsorb cationic dyes such as cationic blue, cationic red GTL, cationic yellow X-6G and the like.