CN111013553A - Methylene blue and rhodamine B adsorbent and preparation method thereof - Google Patents

Abstract

The invention discloses a methylene blue and rhodamine B adsorbent and a preparation method thereof, belonging to the technical field of wastewater treatment.A β -cyclodextrin graft copolymer is prepared by adopting an aqueous solution polymerization method by using β -cyclodextrin, acryloyl and 2-acrylamido-2-methylpropanesulfonic acid as monomers, ammonium persulfate as an initiator and N, N-methylene bisacrylamide as a cross-linking agent, the copolymer is cut into pieces after the reaction is finished, the copolymer is washed by absolute ethyl alcohol and then is put into a sealed bag filled with a proper amount of sodium hydroxide solid, and the sealed bag is put into an oven to be hydrolyzed at 90 ℃ to obtain the methylene blue and rhodamine B adsorbent.

Description

Methylene blue and rhodamine B adsorbent and preparation method thereof

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a methylene blue and rhodamine B adsorbent and a preparation method thereof.

Background

With the development of the dye and printing and dyeing industry, the discharge amount of wastewater is continuously increased, and the production wastewater becomes one of the most main pollution sources of water and soil, thereby causing serious threats to the ecological environment and human health. Most dyes are toxic substances with carcinogenic, teratogenic and mutagenic "triple" effects, such as methylene blue and rhodamine B, which are widely used. The methylene blue is used for dyeing cotton, hemp, silk fabrics and paper, and coloring bamboo and wood. Rhodamine B has been used as a food additive in large quantities, and is prohibited from being used in the food industry because of its carcinogenicity, but rhodamine B is still widely used in industries such as paper making, textile printing and dyeing, leather manufacturing and the like.

Textile printing and dyeing is one of the traditional dominant industries which are the earliest developed in China and have international competitiveness, but is also a typical industry with high energy consumption and high water consumption. The energy consumption of the textile printing and dyeing industry accounts for about 4.4 percent of the total amount of the national industry, the water consumption accounts for about 8.5 percent, and the wastewater discharge amount and the total amount of pollutants are respectively positioned at the second place and the fourth place of the national industrial department. Every 100 m of cloth is dyed in China can generate 4-5 tons of wastewater, about 20-23 hundred million tons of wastewater are generated every year, and the recovery rate of the wastewater is only 7 percent.

The printing and dyeing wastewater has complex components, high organic matter content and difficult biochemical degradation, and belongs to the category of industrial wastewater difficult to treat. Rhodamine B, particularly methylene blue, is a major pollutant in printing and dyeing wastewater. Methylene blue is a phenothiazine dye, rhodamine B is a dibenzo-hexa-oxacyclo dye, the two dyes have poor biodegradability, and if the dyes are discharged into a water body in large quantities without treatment, aquatic plants die and the aerobic environment of the water body is damaged. The pollutants not only cause the pollution of the receiving water body, but also mainly cause the harm to the human health, and have carcinogenic, teratogenic and mutagenic effects.

The prior printing and dyeing wastewater treatment methods used in China comprise a biological method, an extraction method, an adsorption method, a chemical oxidation method and an advanced oxidation method. The adsorption method has simple process and certain advantages in the field of wastewater treatment. The traditional adsorbents for treating dyes mainly comprise carbon materials, alumina, molecular sieves, resins and the like, but the adsorbents have limited adsorption capacity and slow adsorption rate. Therefore, the technical personnel in the field need to solve the problem of providing the methylene blue and rhodamine B adsorbent and the preparation method thereof.

Disclosure of Invention

In view of the above, the invention provides a methylene blue and rhodamine B adsorbent and a preparation method thereof, and the adsorbent is high in adsorption amount and high in adsorption rate.

In order to achieve the purpose, the invention adopts the following technical scheme:

the methylene blue and rhodamine B adsorbent comprises, by weight, β -cyclodextrin 0.6-2 parts, acrylamide 15-25 parts, 2-acrylamido-2-methylpropanesulfonic acid 3-6 parts, N methylene bisacrylamide 2-5 parts, and ammonium persulfate 2-5 parts.

Further, a preparation method of the methylene blue and rhodamine B adsorbent comprises the following specific steps:

(1) adding 0.6-2 parts of β -cyclodextrin into 50 parts of pure water, and heating and dissolving in a water bath to obtain β -cyclodextrin solution;

(2) dissolving 15-25 parts of acrylamide, 3-6 parts of 2-acrylamido-2-methylpropanesulfonic acid and 2-5 parts of N, N methylene bisacrylamide in 50 parts of pure water to obtain a mixed solution;

(3) adding the mixed solution obtained in the step (2) into the β -cyclodextrin solution obtained in the step (1), adding 2-5 parts of ammonium persulfate, stirring for 5-10 min, reacting for 3h at 50-60 ℃, and taking out the product after the product is colorless transparent gel;

(4) cutting the gel obtained in the step (3) into pieces, and washing the pieces with absolute ethyl alcohol; putting the mixture and 4-8 parts of NaOH solid into a sealed bag, carrying out hydrolysis reaction for 8-12 h at 90 ℃, taking out, and drying in a vacuum drying oven at 90 ℃ for 24h to obtain methylene blue and rhodamine B adsorbents.

According to the technical scheme, compared with the prior art, the methylene blue and rhodamine B adsorbent and the preparation method thereof are disclosed, β -cyclodextrin (β -CD), Acrylamide (AM) and 2-acrylamido-2-methylpropanesulfonic Acid (AMPS) are used as monomers, Ammonium Persulfate (APS) is used as an initiator, N, N-Methylene Bisacrylamide (MBA) is used as a cross-linking agent, β -cyclodextrin graft copolymer (β -CD-A-A) is prepared by adopting an aqueous solution polymerization method, after the reaction is finished, the copolymer is cut into pieces, is washed by absolute ethyl alcohol, is put into a sealed bag filled with a proper amount of sodium hydroxide solid, and is put into an oven to be hydrolyzed at 90 ℃ to obtain the methylene blue and rhodamine B adsorbent, the methylene blue and rhodamine B adsorbent prepared by the method is large in adsorption capacity and high in adsorption rate, the maximum adsorption capacity on the Methylene Blue (MB) can reach 2536mg/g, the maximum adsorption capacity on the rhodamine B (RhB) can reach 950mg/g, the adsorption rate on the Methylene Blue (MB) can reach 30min, and the adsorption cost on the Methylene Blue (MB) is lower than that the methylene blue (850 mg/MB) prepared by a simple method, and the cost is lower than that the methylene blue (1380 mg/g).

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a diagram showing a comparison of the forms of methylene blue and rhodamine B adsorbent before and after the adsorption of methylene blue;

wherein a is before methylene blue is adsorbed by an adsorbent; b is after the adsorbent adsorbs methylene blue, and the adsorption process can absorb some water to cause it to swell; c is cutting the adsorbent in b.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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

The preparation method of the methylene blue and rhodamine B adsorbent comprises the following specific steps:

adding β -cyclodextrin 0.8g into pure water 50g, heating in water bath to 60 ℃ for dissolving to obtain a β -cyclodextrin solution, dissolving acrylamide 15g, 2-acrylamido-2-methylpropanesulfonic acid 3g and methylene bisacrylamide 2g in pure water 50g to obtain a mixed solution, uniformly mixing the β -cyclodextrin solution with the mixed solution, adding ammonium persulfate 2g, stirring for 8min, reacting at 55 ℃ for 3h to obtain a colorless transparent gel, taking out, cutting the gel into 10-20 mesh particles, washing with absolute ethyl alcohol, putting the particles and NaOH 4g into a sealed bag, hydrolyzing at 90 ℃ for 10h, taking out, putting into a vacuum drying box, and drying at 90 ℃ for 24h to obtain the methylene blue and rhodamine B adsorbent.

Example 2

The preparation method of the methylene blue and rhodamine B adsorbent comprises the following specific steps:

adding β -cyclodextrin 1g into pure water 50g, heating in water bath to 60 ℃ for dissolving to obtain a β -cyclodextrin solution, dissolving acrylamide 20g, 2-acrylamido-2-methylpropanesulfonic acid 4g and methylene bisacrylamide 3g in pure water 50g to obtain a mixed solution, mixing the β -cyclodextrin solution with the mixed solution uniformly, adding ammonium persulfate 3g, stirring for 10min, reacting at 50 ℃ for 3h to obtain a colorless transparent gel, taking out, cutting the gel into 10-20 mesh particles, washing with absolute ethyl alcohol, putting the particles and NaOH 5g into a sealed bag, hydrolyzing at 90 ℃ for 8h, taking out, putting into a vacuum drying oven, and drying at 90 ℃ for 24h to obtain methylene blue and rhodamine B adsorbents.

Example 3

The preparation method of the methylene blue and rhodamine B adsorbent comprises the following specific steps:

adding 1.5g of β -cyclodextrin into 50g of pure water, heating the mixture in a water bath to 60 ℃ for dissolving to obtain β -cyclodextrin solution, dissolving 25g of acrylamide, 6g of 2-acrylamido-2-methylpropanesulfonic acid and 5g of N, N methylene bisacrylamide into 50g of pure water to obtain mixed solution, uniformly mixing β -cyclodextrin solution with the mixed solution, adding 4g of ammonium persulfate, stirring for 10min, reacting for 3h at the temperature of 60 ℃, taking out a product which is colorless transparent gel, cutting the obtained gel into 10-20-mesh particles, washing the particles with absolute ethyl alcohol, putting the particles and 8g of NaOH solid into a sealed bag, hydrolyzing for 8h at the temperature of 90 ℃, taking out the particles, putting the particles into a vacuum drying box, and drying for 24h at the temperature of 90 ℃ to obtain the methylene blue and rhodamine B adsorbent.

The method for removing methylene blue and rhodamine B in water by adopting the methylene blue and rhodamine B adsorbent prepared by the invention comprises the following steps: the adsorbent is directly mixed with the dye wastewater, the pH value of the solution is adjusted to 5-10 by NaOH, the adsorbent is separated by centrifugation after oscillation adsorption on an oscillator, and the performances of the adsorbent prepared in examples 1-3 are shown in tables 1-3.

TABLE 1 adsorption capacity of the adsorbents in the three examples for methylene blue and rhodamine B adsorbents

Examples	MB adsorption amount (mg/g)	RhB adsorption capacity (mg/g)
			Example 1	2354	895
Example 2	2536	950
			Example 3	2487	907

TABLE 2 variation of methylene blue adsorption amount with time of the adsorbent in example 2

Time (h)	0.5	1	1.5	2	6	24
							Adsorption Capacity (mg/g)	850	1380	1622	1898	2252	2524

TABLE 3 influence of pH on the amount of methylene blue adsorbed by the adsorbent in example 2

pH	5	6	7	8	9	10
							Adsorption Capacity (mg/g)	2273	2394	2468	2502	2522	2530

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (2)

1. The methylene blue and rhodamine B adsorbent is characterized by comprising, by weight, β -cyclodextrin 0.6-2 parts, acrylamide 15-25 parts, 2-acrylamido-2-methylpropanesulfonic acid 3-6 parts, N methylene bisacrylamide 2-5 parts and ammonium persulfate 2-5 parts.

2. The preparation method of the methylene blue and rhodamine B adsorbent according to claim 1, which is characterized by comprising the following specific steps:

(1) adding 0.6-2 parts of β -cyclodextrin into 50 parts of pure water, and heating and dissolving in a water bath to obtain β -cyclodextrin solution;

(2) dissolving 15-25 parts of acrylamide, 3-6 parts of 2-acrylamido-2-methylpropanesulfonic acid and 2-5 parts of N, N methylene bisacrylamide in 50 parts of pure water to obtain a mixed solution;

(3) adding the mixed solution obtained in the step (2) into the β -cyclodextrin solution obtained in the step (1), adding 2-5 parts of ammonium persulfate, stirring for 5-10 min, reacting for 3h at 50-60 ℃, and taking out the product after the product is colorless transparent gel;

(4) cutting the gel obtained in the step (3) into pieces, and washing the pieces with absolute ethyl alcohol; putting the mixture and 4-8 parts of NaOH solid into a sealed bag, carrying out hydrolysis reaction for 8-12 h at 90 ℃, taking out, and drying in a vacuum drying oven at 90 ℃ for 24h to obtain methylene blue and rhodamine B adsorbents.

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