Preparation method of Ag-loaded modified cellulose microspheres and product

Abstract

The invention relates to a preparation method of Ag-loaded modified cellulose microspheres and a product. The microspheres provided by the invention can be prepared by the following steps: firstly, preparing cellulose triacetate microspheres; then, preparing modified cellulose triacetate microspheres; and finally, preparing the Ag-loaded modified cellulose microsphere product. The degradation rate of the Ag-loaded modified cellulose microspheres prepared by the method on rhodamine B in an aqueous solution under an ultrasonic condition reaches 97.4% or above, which indicates that the microspheres prepared by the method are a catalytic material with a very strong degradation function on organic pollutants in a water body, and have a relatively good application prospect in the field of water pollution treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of cellulose microspheres, and particularly to a preparation method and product of Ag-loaded modified cellulose microspheres. Background Art

[0003] Ultrasonic oxidation technology has good application prospects in the degradation of organic dye wastewater. In recent years, the application of metal-based nanocomposites with high efficiency and practicability in catalytic reduction technology has received extensive attention. Due to the characteristics of high catalytic activity, reaction selectivity, and easy preparation of metal nanoparticles, they are considered excellent catalysts in chemical reactions, but they have disadvantages such as high cost, difficult separation, easy aggregation, and non-recyclability. Cellulose is the most abundant renewable natural polymer so far, widely existing in various plants, and it has good stability and chemical modifiability. Therefore, cellulose-based materials can be used as good carriers for metal nanoparticles.

[0004] Microspheres refer to a particulate dispersion system in which drugs are dispersed or adsorbed in a polymer matrix. There are many carrier materials for preparing microspheres, which are mainly divided into natural polymer microspheres (such as starch microspheres, albumin microspheres, gelatin microspheres, and chitosan microspheres, etc.) and synthetic polymer microspheres (such as polylactic acid microspheres). The main raw material of cellulose-based microspheres is cellulose, and cellulose-based microspheres have the advantages of wide raw material sources, stable structural properties, safety and non-toxicity, large specific surface area, etc. Literature research found that there are few reports on the use of cellulose-based microspheres for the degradation of organic pollutants in water bodies.

[0005] Technical Solution

[0006] Aiming at the defects of the prior art, the purpose of the present invention is to provide a preparation method and product of Ag-loaded modified cellulose microspheres, and the microspheres have a strong degradation function for organic pollutants in water bodies and can be used as catalytic material products for the degradation of organic pollutants in water bodies.

[0007] The purpose of the present invention is to provide an Ag-loaded modified cellulose microsphere product, which can be obtained by the following method: First, prepare cellulose triacetate microspheres; then, prepare modified cellulose triacetate microspheres; finally, obtain the Ag-loaded modified cellulose microsphere product.

[0008] Another purpose of the present invention is to provide a preparation method of Ag-loaded modified cellulose microspheres, including the following steps:

[0009] (1) Preparation of cellulose triacetate microspheres: First, dissolve cellulose triacetate in dichloromethane. Second, add Span 80 to the solution and stir for 15 min to obtain a mixed solution. Third, drop the entire mixed solution into an aqueous solution of 0.75 wt% sodium dodecyl sulfate and continuously stir at 450 rpm in a 40 °C water bath for 4 h to obtain a crude product. Finally, wash the crude product alternately with hot distilled water and ethanol, and then vacuum dry at 60 °C for 24 h to obtain cellulose triacetate microspheres.

[0010] Preferably, the dosage ratio of cellulose triacetate, dichloromethane, Span 80, and aqueous sodium dodecyl sulfate solution is 0.6 g∶(35 - 45) mL∶(0.7 - 0.8) g∶(90 - 110) mL.

[0011] (2) Preparation of modified cellulose triacetate microspheres: First, dissolve dopamine hydrochloride in Tris-HCl buffer solution with pH = 8.5 to prepare a 2 mg / mL dopamine hydrochloride solution. Second, disperse the prepared cellulose triacetate microspheres in the dopamine hydrochloride solution and oscillate at room temperature in the dark for 12 h. Third, centrifuge the oscillated mixture to separate and obtain a crude sample coated with polydopamine. Finally, wash the crude sample with deionized water multiple times and vacuum dry the sample at 60 °C for 12 h to obtain modified cellulose triacetate microspheres.

[0012] Preferably, the dosage ratio of cellulose triacetate microspheres to dopamine hydrochloride solution is 60 mg∶(5 - 7) mL.

[0013] (3) Preparation of Ag-loaded modified cellulose microspheres: Weigh the modified cellulose triacetate microspheres and mix them with a 24.4 mM AgNO 3 solution, react at room temperature for 12 hours, and obtain Ag-loaded modified cellulose microspheres after washing and drying.

[0014] Preferably, the dosage ratio of the modified cellulose triacetate microspheres to the AgNO 3 solution is 30 mg∶(5 - 7) mL.

[0015] The present invention has the following beneficial effects:

[0016] (1) The Ag-loaded modified cellulose microspheres prepared by the present invention have a spherical structure, a smooth and porous surface, a uniform pore size distribution, small holes are also formed inside the microspheres, and the surface is coated with metallic Ag. The metallic Ag and the pore channels inside the microspheres have a strong catalytic degradation function for rhodamine B under ultrasonic conditions and in an aqueous solution.

[0017] (2) The degradation rate of the prepared Ag-loaded modified cellulose microspheres of the present invention for Rhodamine B in aqueous solution under ultrasonic conditions reaches more than 97.4%, indicating that the microspheres prepared by the present invention are a catalytic material with a very strong function of degrading organic pollutants in water bodies.

[0018] (3) The raw materials of the prepared Ag-loaded modified cellulose microspheres of the present invention are widely sourced and the main raw materials are renewable, and it has good application prospects in the field of water pollution treatment. Description of the Drawings

[0019] Figure 1 Electron micrograph of the Ag-loaded modified cellulose microsphere a. Detailed Embodiments

[0020] Example 1

[0021] In this example, the Ag-loaded modified cellulose microspheres were prepared by the following method, including the following steps:

[0022] (1) Preparation of cellulose triacetate microspheres: First, 0.6 g of cellulose triacetate was dissolved in 40 mL of dichloromethane; second, 0.75 g of Span 80 was added to the solution and stirred for 15 min to obtain a mixed solution; third, the mixed solution was all dropped into 100 mL of 0.75 wt% sodium dodecyl sulfate aqueous solution, and continuously stirred at 450 rpm in a 40 °C water bath for 4 h to obtain a crude product; finally, the crude product was washed alternately with hot distilled water and ethanol, and then vacuum dried at 60 °C for 24 h to obtain cellulose triacetate microspheres.

[0023] (2) Preparation of modified cellulose triacetate microspheres: First, dopamine hydrochloride was dissolved in Tris-HCl buffer solution with pH = 8.5 to prepare a 2 mg / mL dopamine hydrochloride solution; second, 600 mg of the prepared cellulose triacetate microspheres were dispersed in 60 mL of dopamine hydrochloride solution, and oscillated at room temperature in the dark for 12 h; third, the oscillated mixture was centrifuged to separate and obtain a crude sample coated with polydopamine; finally, the crude sample was washed with deionized water multiple times, and the sample was vacuum dried at 60 °C for 12 h to obtain modified cellulose triacetate microspheres.

[0024] (3) Preparation of Ag-loaded modified cellulose microspheres: Weigh 300 mg of modified cellulose triacetate microspheres and mix them with 60 mL of 24.4 mM AgNO 3 solution, react at room temperature for 12 hours, and obtain Ag-loaded modified cellulose microsphere a after washing and drying. Its electron micrograph is as Figure 1 shown.

[0025] Example 2

[0026] In this embodiment, the Ag-loaded modified cellulose microspheres are prepared by the following method, which includes the following steps:

[0027] (1) Preparation of cellulose triacetate microspheres: First, dissolve 0.6 g of cellulose triacetate in 35 mL of dichloromethane; second, add 0.7 g of Span 80 to the solution and stir for 15 min to obtain a mixed solution; third, drop all of the mixed solution into 90 mL of 0.75 wt% sodium dodecyl sulfate aqueous solution, and continuously stir at 450 rpm in a 40°C water bath for 4 h to obtain a crude product; finally, wash the crude product alternately with hot distilled water and ethanol, and then vacuum dry at 60°C for 24 h to obtain cellulose triacetate microspheres.

[0028] (2) Preparation of modified cellulose triacetate microspheres: First, dissolve dopamine hydrochloride in Tris-HCl buffer solution with pH = 8.5 to prepare a 2 mg / mL dopamine hydrochloride solution; second, disperse 600 mg of the prepared cellulose triacetate microspheres in 50 mL of the dopamine hydrochloride solution, and oscillate at room temperature in the dark for 12 h; third, centrifuge the oscillated mixture to separate and obtain the crude sample coated with polydopamine; finally, wash the crude sample with deionized water multiple times, and vacuum dry the sample at 60°C for 12 h to obtain modified cellulose triacetate microspheres.

[0029] (3) Preparation of Ag-loaded modified cellulose microspheres: Weigh 300 mg of modified cellulose triacetate microspheres and mix them with 50 mL of 24.4 mM AgNO 3 solution, react at room temperature for 12 hours, wash and dry to obtain Ag-loaded modified cellulose microspheres b.

[0030] Example 3

[0031] In this embodiment, the Ag-loaded modified cellulose microspheres are prepared by the following method, which includes the following steps:

[0032] (1) Preparation of cellulose triacetate microspheres: First, dissolve 0.6 g of cellulose triacetate in 45 mL of dichloromethane; second, add 0.8 g of Span 80 to the solution and stir for 15 min to obtain a mixed solution; third, drop all of the mixed solution into 110 mL of 0.75 wt% sodium dodecyl sulfate aqueous solution, and continuously stir at 450 rpm in a 40°C water bath for 4 h to obtain a crude product; finally, wash the crude product alternately with hot distilled water and ethanol, and then vacuum dry at 60°C for 24 h to obtain cellulose triacetate microspheres.

[0033] (2) Preparation of modified cellulose triacetate microspheres: First, dissolve dopamine hydrochloride in Tris-HCl buffer solution with pH = 8.5 to prepare a 2 mg / mL dopamine hydrochloride solution. Second, disperse 600 mg of the prepared cellulose triacetate microspheres in 70 mL of the dopamine hydrochloride solution, and oscillate at room temperature in the dark for 12 h. Third, centrifuge the oscillated mixture to separate the crude sample coated with polydopamine. Finally, wash the crude sample with deionized water multiple times, and vacuum dry the sample at 60 °C for 12 h to obtain the modified cellulose triacetate microspheres.

[0034] (3) Preparation of Ag-loaded modified cellulose microspheres: Weigh 300 mg of the modified cellulose triacetate microspheres and mix them with 70 mL of 24.4 mM AgNO 3 solution, react at room temperature for 12 hours, and obtain Ag-loaded modified cellulose microspheres c after washing and drying.

[0035] Comparative Example A

[0036] Taking Example 1 as a comparison, in this Comparative Example A, change the concentration of the dopamine hydrochloride solution, and adjust "prepare a 2 mg / mL dopamine hydrochloride solution" to "prepare a 0.2 mg / mL dopamine hydrochloride solution" in step (2). Implement other preparation methods according to the preparation method of Example 1 to obtain microspheres d.

[0037] Comparative Example B

[0038] Taking Example 1 as a comparison, in this Comparative Example B, do not load Ag on the modified cellulose triacetate microspheres, that is, do not implement step (3), and implement other preparation methods according to the preparation method of Example 1 to obtain microspheres e.

[0039] Performance evaluation of Ag-loaded modified cellulose microspheres:

[0040] Use the microspheres a - e prepared in the examples and comparative examples to ultrasonically degrade rhodamine B in an aqueous solution. The specific operation of the experiment is as follows: First, weigh the microspheres and place them in a 50 mL conical flask. Then, measure 30 mL of an aqueous solution of rhodamine B with a certain concentration and mix it with the microspheres. Place the conical flask in a controllable ultrasonic device (output power is 100 - 600 W, fixed frequency is 40 kHz), and ultrasonically irradiate it for 2 h under light-shielded conditions. Then, take out part of the solution with a syringe and filter it, analyze its absorbance value with UV-vis, and record the experimental data.

[0041] The degradation rate of rhodamine B can be calculated by formula (1), and three parallel samples are set for each group of experiments. Formula (1) is as follows:

[0042] Degradation rate (%) = [(A 0 - A t ) / A 0× 100% (1)

[0043] wherein, A 0 is the initial absorbance of the rhodamine B solution; A t is the absorbance of the rhodamine B solution after degradation under different conditions. Among them, the degradation rate of the rhodamine B solution is calculated based on the absorbance at its λ max = 553 nm. The results of ultrasonic degradation of rhodamine B by the microspheres a - e prepared in the examples and comparative examples are shown in Table 1.

[0044] Table 1

[0045] Microsphere Degradation rate (%) Microsphere a 98.6 Microsphere b 97.4 Microsphere c 98.9 Microsphere d 74.2 Microsphere e 55.4

[0046] As can be seen from Table 1, the degradation rates of the Ag - modified cellulose microspheres a, b, and c prepared in the examples reach more than 97.4%, which are significantly higher than the degradation rates of the microspheres d and e prepared in the comparative examples. This indicates that: the concentration of the dopamine hydrochloride solution and the loading of Ag on the modified cellulose triacetate microspheres both have important effects on the degradation rate of the microspheres.

Claims

1. A method for preparing Ag-loaded modified cellulose microspheres, characterized in that: The preparation method comprises the following steps: (1) Preparation of cellulose triacetate microspheres: First, cellulose triacetate was dissolved in dichloromethane; second, Span 80 was added to the solution and stirred for 15 minutes to obtain a mixed solution; third, the mixed solution was dripped into a 0.75 wt% sodium dodecyl sulfate aqueous solution, and the mixture was stirred at 450 rpm for 4 hours in a 40°C water bath to obtain a crude product; finally, the crude product was washed alternately with hot distilled water and ethanol, and then vacuum dried at 60°C for 24 hours to obtain cellulose triacetate microspheres; (2) Preparation of modified triacetyl cellulose microspheres: First, dopamine hydrochloride was dissolved in a Tris-HCl buffer solution at pH = 8.5 to prepare a 2 mg / mL dopamine hydrochloride solution; second, the prepared triacetyl cellulose microspheres were dispersed in the dopamine hydrochloride solution and oscillated at room temperature for 12 h in a dark environment; third, the oscillated mixed solution was centrifuged to separate a crude sample coated with polydopamine; finally, the crude sample was washed with deionized water for multiple times, and the sample was vacuum dried at 60°C for 12 h to obtain modified triacetyl cellulose microspheres; (3) Preparation of Ag-loaded modified cellulose microspheres: Weigh modified cellulose triacetate microspheres and mix them with 24.4 mM AgNO3 solution, react them at room temperature for 12 hours, and then wash and dry to obtain Ag-loaded modified cellulose microspheres.

2. The method for preparing Ag-modified cellulose microspheres according to claim 1, characterized in that: The usage ratio of cellulose triacetate, dichloromethane, Span 80 and sodium dodecyl sulfate aqueous solution in step (1) is 0.6 g: (35-45) mL: (0.7-0.8) g: (90-110) mL.

3. The method for preparing Ag-modified cellulose microspheres according to claim 1, characterized in that: The dosage ratio of the cellulose triacetate microspheres to the dopamine hydrochloride solution in step (2) is 60 mg: (5-7) mL.

4. The method for preparing Ag-modified cellulose microspheres according to claim 1, characterized in that: The usage ratio of the modified triacetyl cellulose microspheres to the AgNO3 solution in step (3) is 30 mg: (5-7) mL.

5. A Ag-loaded modified cellulose microsphere, characterized in that: The invention is prepared by the method according to any one of claims 1 to 4.

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