CN107376872B - Preparation method of chitosan-soybean protein composite porous microspheres for lead adsorption - Google Patents

Abstract

The invention discloses a preparation method of chitosan-soybean protein composite porous microspheres for lead adsorption. The chitosan-soybean protein composite porous microspheres are prepared by taking soybean protein and chitosan as raw materials and crosslinking through glutaraldehyde, and are taken as adsorbing materials to carry out micro-column adsorption on lead in a solution, and the adsorption capacity of the chitosan-soybean protein composite porous microspheres on the lead is 42.8 mg/g. The invention overcomes the defects of complex preparation and high price of the existing material, and the defects of complex static adsorption operation, complex steps and the like, reduces the material preparation cost, reduces the manual operation steps, simplifies the operation flow and improves the lead adsorption efficiency.

Description

Preparation method of chitosan-soybean protein composite porous microspheres for lead adsorption

technical field

The invention relates to a preparation method of chitosan-soybean protein composite porous microspheres for lead adsorption.

Background technique

With the development of global industry, lead pollution has posed a great threat to the environment and human health. There is an urgent need to develop fast and convenient lead adsorption materials to meet the needs of environmental testing.

At present, the methods for separating and enriching cadmium in water include precipitation, ion exchange, adsorption, etc. Among them, the adsorption method is widely used because it is simple, efficient, and the adsorption material can be recycled.

At present, there is no relevant research on the preparation of chitosan-soybean protein composite porous microspheres for lead adsorption.

SUMMARY OF THE INVENTION

The present invention provides a preparation method of chitosan-soybean protein composite porous microspheres for lead adsorption.

The idea is as follows: Although various adsorption materials are currently used for the adsorption of lead, their preparation is cumbersome and expensive. The molecular structure of soybean protein is rich in amide groups, and the chitosan molecule contains a large number of amino groups. Therefore, the use of soybean protein and chitosan to prepare low-cost adsorption materials for lead adsorption is simple in material preparation and has practical application value. In this experiment, the chitosan-soybean protein composite porous microspheres were used as the adsorption material for the microcolumns to dynamically adsorb and separate the lead in the sample solution, reducing the manual operation and simplifying the operation process.

The invention relates to chitosan-soybean protein composite porous microspheres and dynamic microcolumn adsorption of lead. When the lead in the sample solution passes through the microcolumns loaded with chitosan-soybean protein composite porous microspheres, the lead interacts with the groups on the microsphere material to be adsorbed, and then the lead is eluted with the eluent and subjected to atomic absorption spectroscopy Determination and testing of the material's ability to adsorb lead.

Specific steps are as follows:

(1) Preparation of chitosan-soybean protein composite porous microspheres:

Weigh 4g of chitosan in a 100mL beaker, add 50mL of acetic acid solution with a concentration of 2% by mass, stir and dissolve, and let stand for 12 hours, remove air bubbles in the solution to obtain a chitosan solution, which is for later use; 2.0g soybean protein and 40mL The secondary water was added to a 100mL beaker, stirred until it was completely dissolved to obtain a soybean protein solution, which was used for later use; 40mL of the above-mentioned chitosan solution and 40mL of the above-mentioned soybean protein solution were mixed, and 2.0g of nano-silica was added, and stirred to obtain chitosan. -Soy protein-silica mixture, set aside.

Take 140 mL of liquid paraffin in a 250 mL three-necked flask, add 4 drops of analytically pure active agent Span 80 dropwise, stir mechanically (300 r/min) for 30 minutes, heat the water bath to 60 °C, and add 60 mL of chitosan-soybean protein-silicon dioxide. The mixture was added dropwise to the above three-necked flask, and continued to stir for two hours until uniform oil bead particles were formed. Then, the pH of the mixture was adjusted to 9.5 with analytically pure sodium hydroxide solution, the temperature of the water bath was raised to 90 °C, and 20 mL of analysis was added. Pure glutaraldehyde solution, after 3 hours of reaction, stand still, cool and filter to obtain solid microsphere particles, alternately wash with water and absolute ethanol for 3-5 times each, in a Soxhlet extractor with a concentration of 95% by mass. Ethanol extraction for 24 hours; the solid microspheres were soaked in sodium hydroxide solution with a concentration of 5.0mol/L for 24 hours, washed with secondary water until neutral, filtered and dried at 40°C, and sieved to obtain 40-60 mesh particles Chitosan-soybean protein composite porous microspheres.

(2) Adsorption of lead by chitosan-soybean protein composite porous microspheres:

The separation and enrichment device is composed of a peristaltic pump, a self-made micro-column ((7cm×0.5mm id), a polytetrafluoroethylene tube (0.8mmi.d) and a connecting joint. A small amount of glass wool is plugged at one end of the micro-column, and the column is loaded by a wet method. Enter the cross-linked soybean protein microspheres prepared in step (1), and then insert a small amount of glass wool, compact and connect well, use a peristaltic pump to pump secondary distillation into the micro-column, wash it for later use; the separation of Pb(II) is rich in The collection steps are as follows: the Pb(II) solution with pH=5.0 is passed through the micro-column at a flow rate of 3.0 mL/min, and then the unadsorbed ions in the micro-column are washed with 5.0 mL of distilled water at a flow rate of 3.0 mL/min. The adsorbed Pb(II) was reversely eluted with 0.1 mol/L HNO ₃ at a flow rate of 3.6 mL/min; the eluted solution was used for subsequent atomic absorption spectrometry.

(3) Detection method:

Determination instrument: atomic absorption spectrophotometer (Beijing Puxi General Instrument Co., Ltd.); instrument conditions for the determination of Pb by graphite furnace atomic absorption spectrometry: wavelength 283.3nm, slit 0.5nm, lamp current 2.0mA, atomizer height- 0.2mm; the measurement procedure of graphite furnace atomic absorption spectrometry is shown in Table 1. The concentration of Pb(II) in the eluate obtained in the above step (2) was determined by graphite furnace atomic absorption spectrometry.

Table 1: Graphite Furnace Atomic Absorption Spectrometry Procedure

program temperature(℃) Heating rate (℃/s) Hold time (s) dry 80 5 5 dry 100 10 10 Ashing 600 10 10 atomized 1900 0 4 purify 1950 1 1

(4) Determination of the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead:

The conditions for the determination of lead by flame atomic absorption spectrometry: wavelength 283.3nm, slit 0.5nm, lamp current 2.0mA, burner height 5.0mm, acetylene flow 1500mL/min, air flow 5000mL/min. The 20.0 μg/mL Pb(II) solution was adsorbed according to step (2), and the effluent was collected every 10 mL. The experiment was terminated until the lead concentration in the effluent was the same as that of the original solution, and each effluent was measured by flame atomic absorption spectrometry. The concentration of Pb(Ⅱ) was calculated, and the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead was calculated.

The invention overcomes the disadvantages of complicated preparation and high price of existing materials, as well as the disadvantages of cumbersome static adsorption operation and complicated steps, reduces material preparation cost, reduces manual operation steps, simplifies operation process, and improves lead adsorption efficiency.

Description of drawings

1 is a scanning electron microscope photograph of the chitosan-soybean protein composite porous microspheres prepared in the embodiment of the present invention.

Detailed ways

Example:

(1) Preparation of chitosan-soybean protein composite porous microspheres:

Weigh 4g of chitosan in a 100mL beaker, add 50mL of acetic acid solution with a concentration of 2% by mass, stir to dissolve, and let stand for 12 hours, remove air bubbles in the solution to obtain a chitosan solution for later use. 2.0g soybean protein and 40mL secondary water were added into a 100mL beaker, stirred until dissolved completely to obtain a soybean protein solution, for subsequent use; 40mL of the above-mentioned chitosan solution and 40mL of the above-mentioned soybean protein solution were mixed, and 2.0g of nano-silica was added, Stir evenly to obtain a chitosan-soybean protein-silicon dioxide mixed solution, which is for later use.

Take 140 mL of liquid paraffin in a 250 mL three-necked flask, add 4 drops of analytically pure active agent Span 80 dropwise, stir mechanically (300 r/min) for 30 minutes, heat the water bath to 60 °C, and add 60 mL of chitosan-soybean protein-silicon dioxide. The mixture was added dropwise to the above three-necked flask, and continued to stir for two hours until uniform oil bead particles were formed. Then, the pH of the mixture was adjusted to 9.5 with analytically pure sodium hydroxide solution, the temperature of the water bath was raised to 90 °C, and 20 mL of analysis was added. Pure glutaraldehyde solution, after 3 hours of reaction, stand, cool and filter to obtain solid microsphere particles, alternately wash with water and absolute ethanol 3 times each, and extract with 95% ethanol in a Soxhlet extractor 24 hours. The solid microsphere particles were soaked in sodium hydroxide solution with a concentration of 5.0mol/L for 24 hours, washed with secondary water until neutral, filtered and dried at 40°C, and sieved to obtain chitosan with a particle size of 40-60 mesh. - Soy protein composite porous microspheres. The scanning electron microscope photograph of chitosan-soybean protein composite porous microspheres is shown in Figure 1.

(2) Adsorption of lead by chitosan-soybean protein composite porous microspheres:

The separation and enrichment device consists of a peristaltic pump, a self-made micro-column (7cm×0.5mm id), a polytetrafluoroethylene tube (0.8mmi.d) and a connecting joint. One end of the micro-column is plugged with a small amount of glass wool, and the cross-linked soybean protein microspheres prepared in step (1) are loaded into the column by wet method, and then a small amount of glass wool is plugged in, compacted and connected well, and the secondary distilled water is pumped in by a peristaltic pump. The micro-column is used after washing; the separation and enrichment steps of Pb(II) are as follows: Pb(II) solution with pH=5.0 is passed through the micro-column at a flow rate of 3.0mL/min, and then washed with 5.0mL distilled water at a flow rate of 3.0mL/min To remove the unadsorbed ions in the micro-column, use 10.0 mL of HNO ₃ with a concentration of 0.1 mol/L to reverse elute the adsorbed Pb(II) at a flow rate of 3.6 mL/min; the elution solution is used for subsequent atomic absorption spectrometry determination .

(3) Detection method:

Determination instrument: atomic absorption spectrophotometer (Beijing Puxi General Instrument Co., Ltd.); instrument conditions for the determination of Pb by graphite furnace atomic absorption spectrometry: wavelength 283.3nm, slit 0.5nm, lamp current 2.0mA, atomizer height- 0.2mm; the measurement procedure of graphite furnace atomic absorption spectrometry is shown in Table 1. The concentration of Pb(II) in the eluate obtained in the above step (2) was determined by graphite furnace atomic absorption spectrometry.

Table 1: Graphite Furnace Atomic Absorption Spectrometry Procedure

program temperature(℃) Heating rate (℃/s) Hold time (s) dry 80 5 5 dry 100 10 10 Ashing 600 10 10 atomized 1900 0 4 purify 1950 1 1

(4) Determination of the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead:

The conditions for the determination of lead by flame atomic absorption spectrometry: wavelength 283.3nm, slit 0.5nm, lamp current 2.0mA, burner height 5.0mm, acetylene flow 1500mL/min, air flow 5000mL/min. The 20.0 μg/mL Pb(II) solution was adsorbed according to step (2), and the effluent was collected every 10 mL. The experiment was terminated until the lead concentration in the effluent was the same as that of the original solution, and the effluent was measured by flame atomic absorption spectrometry. The Pb(Ⅱ) concentration was calculated, and the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead was calculated to be 42.8 mg/g.

Claims (1)

1. a preparation method for the chitosan-soybean protein composite porous microspheres for lead adsorption, is characterized in that concrete steps are: (1) Preparation of chitosan-soybean protein composite porous microspheres: Weigh 4 g of chitosan in a 100 mL beaker, add 50 mL of acetic acid solution with a mass percentage concentration of 2%, stir and dissolve and let stand for 12 hours, remove air bubbles in the solution to obtain a chitosan solution, which is for later use; 2.0 g of soybean protein and 40 mL of secondary water was added to a 100 mL beaker, stirred until it was completely dissolved to obtain a soybean protein solution, which was used for later use; 40 mL of the above chitosan solution and 40 mL of the above soybean protein solution were mixed, and 2.0 g of nano-silica was added, and stirred. The chitosan-soybean protein-silicon dioxide mixed solution is uniformly obtained, for subsequent use; Take 140 mL of liquid paraffin in a 250 mL three-necked flask, add 4 drops of analytically pure active agent Span 80 dropwise, stir mechanically at 300 r/min for 30 minutes, heat the water bath to 60 °C, and mix 60 mL of chitosan-soybean protein-silicon dioxide. The liquid was added dropwise to the above three-necked bottle, and continued to stir for two hours until uniform oil beads were formed. Then, the pH of the mixture was adjusted to 9.5 with analytical pure sodium hydroxide solution, the temperature of the water bath was raised to 90 °C, and 20 mL was added for analysis. Pure glutaraldehyde solution, after 3 hours of reaction, stand still, cool and filter to obtain solid microsphere particles, alternately wash with water and absolute ethanol for 3-5 times each, in a Soxhlet extractor with a mass percentage concentration of 95%. Ethanol extraction for 24 hours; the solid microspheres were soaked in sodium hydroxide solution with a concentration of 5.0 mol/L for 24 hours, washed with secondary water until neutral, filtered and dried at 40 ° C, and sieved to obtain 40-60 mesh particles Chitosan-soybean protein composite porous microspheres with diameters; (2) Adsorption of lead by chitosan-soybean protein composite porous microspheres: The separation and enrichment device is composed of a peristaltic pump, a self-made micro-column and a connecting joint; one end of the micro-column is plugged with a small amount of glass wool, and the cross-linked soybean protein microspheres prepared in step (1) are loaded into the column by wet method, and then a small amount of glass wool is inserted into the column. , compacted and connected well, use the peristaltic pump to pump the secondary distilled water into the micro-column, wash it for later use; the separation and enrichment steps of Pb(II) are as follows: Pb(II) solution with pH=5.0 is pumped at a flow rate of 3.0 mL/min Passed through the micro-column, then washed the unadsorbed ions in the micro-column with 5.0 mL of distilled water at a flow rate of 3.0 mL/min, and reversely eluted the adsorbed ions with 10.0 mL of _HNO3 with a concentration of 0.1 mol/L at a flow rate of 3.6 mL/min. of Pb(II); the elution solution was used for subsequent atomic absorption spectrometry; (3) Detection method: Determination instrument: atomic absorption spectrophotometer; instrument conditions for the determination of Pb by graphite furnace atomic absorption spectrometry: wavelength 283.3 nm, slit 0.5 nm, lamp current 2.0 mA, atomizer height -0.2 mm; graphite furnace atomic absorption spectrometry program As shown in Table 1; use graphite furnace atomic absorption spectrometry to measure the concentration of Pb(II) in the eluate obtained in the above step (2); Table 1: Graphite Furnace Atomic Absorption Spectrometry Procedure program Temperature (℃) Heating rate (℃/s) Hold time (s) dry 80 5 5 dry 100 10 10 Ashing 600 10 10 atomized 1900 0 4 purify 1950 1 1 (4) Determination of the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead: The conditions for the determination of lead by flame atomic absorption spectrometry: wavelength 283.3 nm, slit 0.5 nm, lamp current 2.0 mA, burner height 5.0 mm, acetylene flow 1500 mL/min, air flow 5000 mL/min; 20.0 μg/mL Pb (II) The solution is adsorbed according to step (2), the effluent is collected every 10 mL, and the experiment is terminated until the lead concentration in the effluent is the same as the original solution concentration, and the Pb(II) in each effluent is determined by flame atomic absorption spectrometry. concentration, and the adsorption capacity of chitosan-soybean protein composite porous microspheres for lead was calculated.

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