A kind of interlayer modified hectorite diatomite composite material and its preparation method and use

Abstract

The present invention provides a method for preparing an interlayer modified hectorite diatomite composite material, comprising the following steps: step (1): adding a magnesium-containing compound, a lithium-containing compound, and a corresponding amount of diatomite to deionized water, mixing them thoroughly, placing them in a reactor for reaction, cooling them to room temperature after the reaction, washing and collecting them, and drying them to obtain a hectorite diatomite precursor; step (2): adding a hectorite diatomite precursor, hexadecyltrimethylammonium bromide, and a certain amount of ethanol solution to a reactor, cooling them to room temperature after the reaction, washing and collecting them, and drying them to obtain the modified hectorite diatomite, and then heating them in a nitrogen gas stream to obtain an interlayer modified hectorite diatomite composite material. The present invention also provides the use of the composite material prepared by the preparation method for treating dye wastewater. The new material prepared by the preparation method of the present invention has good adsorption to anionic and cationic dyes, realizing the innovative idea of ​​treating environmental pollution with clay materials.

Description

Technical Field

[0001] The invention belongs to the field of water treatment materials, and in particular relates to an interlayer modified hectorite diatomite composite material and a preparation method and application thereof. Background Art

[0002] Environmental pollution is one of the three major social problems that the world urgently needs to solve today, among which the excessive discharge of dyes into water has aroused strong concern. Organic dyes are frequently used in various dyeing industries such as textiles, printing and dyeing, leather, and papermaking, resulting in the generation of a large amount of dye-containing wastewater. It is estimated that the production of textile dyes worldwide is more than 400,000 tons. A large amount of printing and dyeing wastewater entering the water environment will have a long-term negative impact on the water environment, and ultimately affect the health of aquatic organisms and humans. During the printing and dyeing process, about 10% to 20% of dyes are discharged as wastewater and enter rivers, lakes, seas, and surface water. The dyes in the wastewater can absorb light, reduce the transparency of the water body, affect the growth of aquatic organisms and microorganisms, are not conducive to the self-purification of the water body, and are easy to cause visual pollution. The adsorption method is considered to be the most effective wastewater treatment technology because of its high efficiency, low cost, simple operation, and environmental friendliness. Activated carbon, metal oxides, zeolites, clays, etc. are often used as adsorbents. However, most of them are expensive, have low adsorption capacity, or have complex preparation processes. In addition, after the adsorption treatment is completed, centrifugation, filtration, sedimentation and other methods are generally used to separate the adsorbent from the treated water. However, the entire separation process is time-consuming and complicated, and incomplete separation will cause secondary pollution of the water quality.

[0003] Therefore, it is imperative to design and prepare efficient, stable, environmentally friendly, and low-cost adsorbents for the simultaneous removal of anionic and cationic dyes.

[0004] In order to solve the above problems, the present invention is proposed. Summary of the invention

[0005] The present invention proposes to further hydrothermally treat a precursor obtained by a one-step hydrothermal method of diatomite and laponite with CTAB and calcine it under an anaerobic environment to obtain a new type of wastewater treatment material, and apply it to simultaneously remove anionic dyes represented by Congo red, thereby realizing the concept of waste utilization and ecological environmental protection from the source.

[0006] The first aspect of the present invention provides a method for preparing an interlayer modified hectorite diatomite composite material, which comprises the following steps:

[0007] Step (1): adding a magnesium-containing compound, a lithium-containing compound and a corresponding amount of diatomaceous earth into deionized water, mixing them thoroughly, placing them into a reactor for reaction, cooling them to room temperature after the reaction, washing, collecting them and drying them to obtain a hectorite diatomaceous earth precursor;

[0008] Step (2): adding a hectorite diatomite precursor, hexadecyltrimethylammonium bromide and a certain amount of ethanol solution into a reactor, cooling to room temperature after the reaction is completed, washing, collecting and drying to obtain the modified hectorite diatomite, and then heating in a nitrogen gas flow to obtain an interlayer modified hectorite diatomite composite material.

[0009] Preferably, the magnesium-containing compound in step (1) is one or more of magnesium hydroxide, magnesium chloride, magnesium oxide and magnesium chloride.

[0010] Preferably, the lithium-containing compound in step (1) is one or more of lithium fluoride, lithium hydride, lithium oxide and lithium carbonate.

[0011] The second aspect of the present invention provides an interlayer modified hectorite diatomite composite material prepared by the preparation method described in the first aspect of the present invention.

[0012] The third aspect of the present invention provides a use of the interlayer modified hectorite diatomite composite material prepared by the preparation method described in the first aspect of the present invention for treating dye wastewater, characterized in that the interlayer modified hectorite diatomite composite material is added to wastewater containing anionic and cationic dyes to remove the anionic and cationic dyes.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. Prior art has many researches and uses matrix supported nano materials to enhance its application in water environment treatment, such as montmorillonite, vermiculite, carbon fiber, porous carbon, etc. Various materials all have their shortcomings, whether it is single component material or multi-component composite material, they are mostly expensive, have low adsorption capacity, single adsorption object, or complicated preparation process, common materials can not be effectively recovered, causing the whole process to generate too much cost, insufficient recovery, and also causing secondary pollution to water body. The new material prepared by the preparation method of the present invention has good adsorption to anionic and cationic dyes, and has low production cost, is environmentally friendly, and has realized the innovative idea of ​​treating environmental pollution with clay materials.

[0015] 2. The present invention uses diatomite three-dimensional material and hectorite two-dimensional material to composite and then perform CTAB modification to obtain interlayer modified hectorite diatomite composite material, creatively realizing the multifunctional application of a multi-effect composite material from the modification method, which is more in line with environmental requirements and has higher market value. It increases the additional value of diatomite as a strategic resource mineral and opens the way for diatomite to prepare layered graphene-like carbon composite materials. The preparation method provides ideas for subsequent environment and energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 X-ray diffractometer (a) and infrared spectrum (b) of CTAB-La@D;

[0017] Figure 2 This is the SEM image of the product 1.0CTAB-La@D in Example 2;

[0018] Figure 3 The adsorption performance of CTAB-La@D on Congo red solution (the concentration of Congo red in Figures a, b, and c is 100 mg / L, and the temperature in Figure d is 25 degrees Celsius);

[0019] Figure 4 The adsorption performance of 1.0CTAB-La@D on methylene blue (a) and methyl orange solution (b). DETAILED DESCRIPTION

[0020] The following examples illustrate the process described in the present invention, but the present invention is not limited to these examples.

[0021] Example 1

[0022] Step (1): Preparation of hectorite diatomite precursor by one-step hydrothermal method

[0023] 3.48 g of Mg(OH) 2 , 0.4g of LiF, and 50ml of deionized water were mixed in sequence and magnetically stirred for 10 minutes, and then 6.4g of diatomaceous earth was added, followed by magnetic stirring for 5-10 minutes. Then it was placed in a polytetrafluoroethylene-lined stainless steel autoclave and reacted at 180°C for 6 hours. After cooling to room temperature, the sample was collected by centrifugal washing with deionized water and alcohol several times. Finally, the hectorite diatomite precursor La@D was obtained by drying at 60°C for 12h.

[0024] Step (2): Preparation of interlayer modified hectorite diatomite composite material

[0025] Weigh 75 mg of CTAB and put it into a polytetrafluoroethylene liner, add 100 mg of hectorite diatomite precursor, add 70 ml of 50% ethanol solution, and then put it into an autoclave and react at 60 ° C for 8 hours. After cooling to room temperature, the sample was collected by centrifugal washing with deionized water and alcohol several times. The modified hectorite diatomite composite material was obtained by drying at 60 ° C for 12 hours, and then heated at a predetermined temperature of 700 ° C for 4 hours at a heating rate of 10 ° C / min under a nitrogen flow, and then collected to obtain an interlayer modified hectorite diatomite composite material, which was named 0.75CTAB-La@D.

[0026] Example 2

[0027] The other conditions were the same as those in Example 1, except that 100 mg of CTAB was added to the polytetrafluoroethylene liner in step 2, and the obtained interlayer modified hectorite diatomite composite material was named 1.0CTAB-La@D.

[0028] Example 3

[0029] The other conditions were the same as those in Example 1, except that 150 mg of CTAB was added to the polytetrafluoroethylene liner in step 2, and the obtained interlayer modified hectorite diatomite composite material was named 1.5CTAB-La@D.

[0030] Application Example 1

[0031] The components of the prepared interlayer modified hectorite diatomite composite material were analyzed by X-ray diffractometer and Fourier transform infrared spectroscopy. Figure 1 As shown in (a), the X-ray diffractometer clearly shows the crystal structure of hectorite and silica, such as Figure 1 As shown in (b), the three interlayer modified hectorite diatomite composites all showed a -1 and 1476cm -1 The characteristic peak of CTAB indicates that the three interlayer modified hectorite diatomite composites are successfully modified, and with the increase of CTAB amount, the peak intensity of the nanocomposite material gradually increases.

[0032] Application Example 2

[0033] The surface morphology of the interlayer modified hectorite diatomite composite material (1.0CTAB-La@D) after calcination was analyzed by scanning electron microscopy. Figure 2 It was found that the carbonization temperature described in the present invention is conducive to the formation of graphene carbon and will not destroy the 3D structure of diatomite.

[0034] Application Example 3

[0035] The adsorption experiments in the present invention were carried out on a constant temperature orbital shaker at different temperatures. 30 mg of the interlayer modified hectorite diatomite composite material was placed in 100 mL of dye solutions (Congo red, methylene blue MB, methyl orange MO) freshly prepared at different concentrations. In addition, the initial concentration and final equilibrium concentration of the dye solution were measured at the characteristic absorption wavelength using a UV-visible spectrophotometer (AOELAB A590). The maximum absorption capacity of the composite material at equilibrium was the dye solution (q e , mg / g) is calculated using formula (1).

[0036]

[0037] where Co and Ce (mg / L) are the initial and final concentrations of the dye solution, respectively; V (L) is the volume of the solution; and m (g) is the mass of the composite material.

[0038] from Figure 3 , Figure 4It can be seen that the three materials have good adsorption performance for different dye solutions. For Congo red solution, its adsorption performance at different temperatures was analyzed and it was found that its adsorption performance decreased slightly with the increase of temperature. A similar analysis was also done on methyl orange solution (the initial concentration of MB was 200 mg / L, and the initial concentration of MO was mg / L). It was found that the adsorption capacity of methyl orange of 1.0CTAB-La@D was about 200 mg / g, while its adsorption capacity for methylene blue solution was about 600 mg / g. Therefore, based on the adsorption performance of different dye solutions, it can be shown that the material has good adsorption for a variety of dye solutions and has broad application prospects.

Claims

1. A method for preparing an interlayer modified hectorite diatomite composite material, It is characterized in that It includes the following steps: Step (1): adding a magnesium-containing compound, a lithium-containing compound and a corresponding amount of diatomaceous earth into deionized water, mixing them thoroughly, placing them into a reactor for reaction, cooling them to room temperature after the reaction, washing, collecting them and drying them to obtain a hectorite diatomaceous earth precursor; Step (2): adding a hectorite diatomite precursor, hexadecyltrimethylammonium bromide and a certain amount of ethanol solution into a reactor, cooling to room temperature after the reaction is completed, washing, collecting and drying to obtain modified hectorite diatomite, and then heating in a nitrogen gas flow to obtain an interlayer modified hectorite diatomite composite material.

2. The preparation method according to claim 1, It is characterized in that The magnesium-containing compound in step (1) is one or more of magnesium hydroxide, magnesium chloride and magnesium oxide.

3. The preparation method according to claim 1, It is characterized in that The lithium-containing compound in step (1) is one or more of lithium fluoride, lithium hydride, lithium oxide and lithium carbonate.

4. An interlayer modified hectorite diatomite composite material prepared by the preparation method according to claim 1.

5. Use of the interlayer modified hectorite diatomite composite material prepared by the preparation method according to claim 1 for treating dye wastewater, It is characterized in that Adding the interlayer modified hectorite diatomite composite material to wastewater containing anionic and cationic dyes can remove the anionic and cationic dyes.

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