CN110560007A

CN110560007A - Preparation process of chloramphenicol adsorbent

Info

Publication number: CN110560007A
Application number: CN201910796067.3A
Authority: CN
Inventors: 江国防; 吴应辉; 杨志军
Original assignee: Hunan Yueda Technology Co Ltd
Current assignee: Hunan Yueda Technology Co Ltd
Priority date: 2019-08-27
Filing date: 2019-08-27
Publication date: 2019-12-13
Anticipated expiration: 2039-08-27
Also published as: CN110560007B

Abstract

the embodiment of the invention provides a preparation process of a chloramphenicol adsorbent, which comprises the steps of firstly crushing pine needles to obtain a larger surface area, then soaking pine needle powder in a modifier solution to load a modifier on the pine needle powder, standing and washing, and then carrying out secondary drying treatment on the pine needle powder to obtain the chloramphenicol adsorbent. The preparation process provided by the embodiment of the invention carries out resource utilization on the original waste pine needles, and the pine needles after adsorbing chloramphenicol can be used as organic fertilizer for improving soil conditions, thereby solving the problem of development and utilization of forestry byproducts to a certain extent, providing a new approach for water eutrophication, and having good application prospect and environmental benefit.

Description

preparation process of chloramphenicol adsorbent

Technical Field

The invention belongs to the technical field of material modification, and particularly relates to a preparation process of a chloramphenicol adsorbent.

background

Chloramphenicol (CAP), a crystalline powdery substance isolated from the culture broth of streptomyces venezuelae (streptomyces venezuelae) by Ehrlichz in 1947, is the first antibiotic that can be artificially synthesized, and is currently mainly synthesized by artificial methods. Because of good antibacterial action and pharmacokinetic properties, the compound is commonly used for preventing and treating diseases of fishes and the like in aquaculture. But has the possibility of mutagenesis and canceration, has serious toxicity to the hematopoietic system and the digestive system of the human body, and can also cause harm to the ecological environment and human health through the transmission of a food chain.

Common methods for removing chloramphenicol are photocatalysis, Fenton oxidation, microwave radiation, and adsorption. The photocatalysis method has the advantages of stable system, energy conservation, short time and high efficiency, but the photocatalyst has high cost, difficult preparation and difficult recycling. The Fenton oxidation method has high removal efficiency and easily obtained raw materials, but needs strong stirring in the reaction, has large energy consumption, is difficult to control the reaction condition, and is difficult to treat precipitates after the reaction. The microwave radiation method has high removal efficiency and high speed, but has large energy consumption, and other substances in soil can be damaged due to the special design of reaction sites. The adsorption method has simple process, simple operation and stable system, and in recent years, the adsorption technology is used for alleviating water pollution and becomes one of the most effective methods for treating water pollution. The modified biomass adsorption material has better prospect due to the characteristics of environmental friendliness, convenient preparation, easy acquisition and the like. Compared with other traditional materials, the modified biomass adsorption material has the advantages of high adsorption rate, low cost, strong regeneration capacity and the like, is convenient to recycle waste resources, and has quite high operability.

However, the existing chloramphenicol adsorbent is most commonly activated carbon, and the adsorption effect on chloramphenicol is not ideal.

Disclosure of Invention

in order to solve the problem that the adsorbing effect of the adsorbent on chloramphenicol is not ideal in the prior art, the embodiment of the invention aims to provide a preparation process of a chloramphenicol adsorbent.

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

a preparation process of a chloramphenicol adsorbent comprises the following steps:

s1: drying pine needles for the first time and then crushing the dried pine needles;

S2: soaking the pine needle powder obtained in the step S1 in a modifier solution after extraction treatment, primary cleaning and secondary drying treatment;

s3: adjusting the pH value of the modifier solution in the step S2 and then standing;

S4: and (5) carrying out third drying treatment on the pine needle powder treated in the step S3 after the second cleaning, so as to obtain the chloramphenicol adsorbent.

In the process, pine needles are firstly crushed to obtain a larger surface area, then pine needle powder is subjected to extraction treatment, the purpose of the extraction treatment is to destroy the outer cuticle structure of the pine needles, so that the pine needle powder is loose and porous, the fiber structure is exposed, then a modifier is loaded on the microstructure of the pine needle powder, and then the chloramphenicol adsorbent can be obtained by standing, cleaning and drying. The preparation process is simple, the production cost is low, the prepared adsorbent has strong adsorption capacity on chloramphenicol, has high adsorption selectivity on chloramphenicol, is easy to desorb, and can be recycled for multiple times. Meanwhile, the preparation process carries out resource utilization on the originally abandoned pine needles, and has good application prospect and environmental benefit.

Preferably, the screening range of the crushing treatment in the step S1 is less than 60 meshes.

Preferably, the temperature of the primary drying is 70-90 ℃.

Further preferably, the temperature of the first drying treatment is 80 ℃.

Preferably, the concentration of the modifier solution is 0.2-0.8 mol/L.

Preferably, the modifier comprises phenylenediamine.

Phenylenediamine, also known as "User" D, is one of the simplest aromatic diamines, and is also a widely used intermediate, and can be used to prepare azo dyes, high molecular polymers, and also to produce fur coloring agents, rubber antioxidants, and photo developers.

Preferably, the extraction agent of the extraction process of step S2 includes supercritical carbon dioxide and an expansion liquid.

Preferably, the soaking time in the step S2 is 12-16 h.

Preferably, the modifier solution of step S3 has a pH greater than 7.

further preferably, the modifier solution in the step S3 has a pH of 8-9.

Preferably, the standing time in step S3 is 24 h.

In step S3, the reagent used to adjust the pH is sodium hydroxide.

The pH adjustment with aqueous sodium hydroxide is due to the fact that sodium hydroxide is capable of releasing hydroxyl ions (OH)^-) The pH value can be kept in a certain range, and the phenylenediamine can be loaded on the modified pine needles in a molecular form to the greatest extent.

preferably, the temperature of the third drying process in step S4 is 80 ℃.

In step S4, the second washing is performed by washing with distilled water until the total organic content is constant after the measurement by the organic carbon meter.

the purpose of the second cleaning is to clean the reaction product and remove organic substances attached to the surface of the reaction product, so as to facilitate subsequent reaction or use.

The cleaning process is repeated for a plurality of times until the total organic matter content of the washed clean water is constant after the detection of an organic carbon detector.

The third drying is preferably carried out by pulverizing and then thermally hydrolyzing. The secondary crushing treatment is beneficial to more rapid and uniform treatment of the pine needles in the subsequent treatment and loading process.

The method for extracting the effective substances in the pine needle powder comprises the following steps:

Collecting pulverized folium Pini, and subjecting to supercritical CO₂and soaking in swelling liquid, washing the residue with distilled water until the supernatant is colorless and transparent, and drying at 80 deg.C to constant weight to obtain folium Pini powder. Wherein the swelling liquid refers to 95% ethanol. The feeding ratio of the pine needle powder to the expansion liquid is 100 g: 200 to 250 ofmL。

When the chloramphenicol adsorbent prepared by the preparation process is actually used, the chloramphenicol adsorbent is added into a solution to be adsorbed, and the ideal adsorption condition is an acidic condition with pH of 2-6, a room temperature and adsorption time of 100-120 min.

the chloramphenicol adsorbent prepared by the preparation process has the equilibrium adsorption capacity of 91.2mg/g for chloramphenicol, and the adsorption equilibrium data conforms to a Freundlich model. The adsorption kinetics curve conforms to the second order kinetics equation. Belongs to multilayer adsorption.

After the chloramphenicol adsorbent prepared by the preparation process is used, the desorption rate of the chloramphenicol adsorbent in a 50% ethanol solution reaches 73%.

The embodiment of the invention has the beneficial effects

1. According to the preparation process of the chloramphenicol adsorbent provided by the embodiment of the invention, pine needles are firstly crushed to obtain a larger surface area, then pine needle powder is soaked in a modifier solution, so that the modifier is loaded on the pine needle powder, and the pine needle powder is subjected to secondary drying treatment after standing and washing to obtain the chloramphenicol adsorbent, and the preparation process is simple in method and low in production cost;

2. the preparation process provided by the embodiment of the invention carries out resource utilization on the original waste pine needles, and the pine needles after adsorbing chloramphenicol can be used as organic fertilizer for improving soil conditions, thereby solving the problem of development and utilization of forestry byproducts to a certain extent, providing a new approach for water eutrophication, and having good application prospect and environmental benefit;

3. When the chloramphenicol adsorbent prepared by the process of the embodiment of the invention is actually used, the chloramphenicol adsorbent is added into a solution to be adsorbed, and the ideal adsorption condition is an acidic condition with pH of 2-6, the temperature is room temperature, and the adsorption time is 100-120 min;

4. the equilibrium adsorption capacity of the chloramphenicol adsorbent prepared by the process of the embodiment of the invention to chloramphenicol is 91.2mg/g, the adsorption equilibrium data conforms to a Freundlich model, the adsorption kinetics curve conforms to a two-level kinetics equation, and the chloramphenicol adsorbent belongs to multilayer adsorption;

5. after the chloramphenicol adsorbent prepared by the process provided by the embodiment of the invention is used, the desorption rate of the chloramphenicol adsorbent in a 50% ethanol solution reaches 73%.

drawings

FIG. 1 is a scanning electron microscope image of the surface topography of the original pine needles.

FIG. 2 is a scanning electron microscope image of the surface topography of the chloramphenicol adsorbent prepared in example 2.

FIG. 3 is a graph showing adsorption curves at different temperatures using the chloramphenicol adsorbent of example 2.

FIG. 4 is a graph showing the determination of adsorption kinetics using the chloramphenicol adsorbent of example 3;

FIG. 5 is a graph showing the effect of pH on adsorption using the chloramphenicol adsorbent of example 2.

Detailed Description

The embodiment of the invention provides a preparation process of a chloramphenicol adsorbent, which comprises the steps of crushing pine needles to obtain a larger surface area, extracting pine needle powder to make the pine needle powder loose and porous and expose a fiber structure, loading a modifier on a microstructure of the pine needle powder, standing, cleaning and drying to obtain the chloramphenicol adsorbent.

in order to better understand the above technical solutions, the above technical solutions will be described in detail with reference to specific embodiments.

Example 1

Wherein the screening range of the crushing treatment in the step S1 is less than 60 meshes. The temperature for the first drying is 70-90 ℃. The temperature of the first drying treatment was 80 ℃. The concentration of the modifier solution was 0.2 mol/L. The modifier comprises phenylenediamine.

The extractant of the extraction process of step S2 includes supercritical carbon dioxide and an expansion liquid. The soaking time is 12 h.

The pH value of the modifier solution in the step S3 is more than 7, preferably 8-9. The standing time in the step S3 is 24 h. The reagent used to adjust the pH was sodium hydroxide.

The temperature of the third drying treatment in step S4 was 80 ℃. In step S4, the second washing is performed by washing with distilled water until the total organic content is constant after the measurement by the organic carbon meter. The purpose of the second cleaning is to clean the reaction product and remove organic substances attached to the surface of the reaction product, so as to facilitate subsequent reaction or use. The cleaning process is repeated for a plurality of times until the total organic matter content of the washed clean water is constant after the detection of an organic carbon detector.

Collecting pulverized folium Pini, and subjecting to supercritical CO₂And an expanding liquid, the residue remaining after impregnation,Washing with distilled water until the supernatant is colorless and transparent, and drying at 80 deg.C to constant weight to obtain folium Pini powder extracted with effective components. Wherein the swelling liquid refers to 95% ethanol. The feeding ratio of the pine needle powder to the expansion liquid is 100 g: 200-250 mL.

Example 2

The example actually prepares a chloramphenicol adsorbent, which specifically comprises:

washing pine needles, drying in an oven at 80 ℃ to constant weight, crushing and grinding the dried pine needles, and collecting the crushed pine needles below 60 meshes;

Taking 100g of crushed pine needles, and subjecting to supercritical CO₂200mL of 95% NaOH solution, extracting the residual residue after 10h of the active ingredients of the larch needles, washing the residue with distilled water until the supernatant is colorless and transparent, and drying the residue at 80 ℃ to constant weight to obtain modified pine needles;

Putting 20g of modified pine needles into 200mL0.2mol/L phenylenediamine solution, stirring for 1 hour, then depositing for 10 hours, then dripping sodium hydroxide solution under the stirring condition, controlling the pH value to be 8-9, standing and standing for 24 hours, and stirring for 5 minutes at intervals of 3 hours;

And (3) after the load is deposited, circularly washing the pine needles by using distilled water, and drying the pine needles in an oven at the temperature of 80 ℃ to constant weight to obtain the chloramphenicol adsorbent. The original surface topography of pine needles is shown in fig. 1, and the surface topography of the chloramphenicol adsorbent prepared by the present example is shown in fig. 2.

Example 3

Taking 100g of crushed pine needles, and subjecting to supercritical CO₂200mL of 95% NaOH solution, extracting the residual residue after 12h of the active ingredients of the larch needles, washing the residue with distilled water until the supernatant is colorless and transparent, and drying the residue at 80 ℃ to constant weight to obtain modified pine needles;

Putting 20g of modified pine needles into 200mL0.4mol/L phenylenediamine solution, stirring for 1 hour, then depositing for 12 hours, then dripping sodium hydroxide solution under the stirring condition, controlling the pH value to be 8-9, standing and standing for 24 hours, and stirring for 5 minutes at intervals of 3 hours;

and (3) after the load is deposited, circularly washing the pine needles by using distilled water, and drying the pine needles in an oven at the temperature of 80 ℃ to constant weight to obtain the chloramphenicol adsorbent.

Example 4

Taking 100g of crushed pine needles, and subjecting to supercritical CO₂200mL of 95% NaOH solution, extracting the residual residue after 14h of the active ingredients of the larch needles, washing the residue with distilled water until the supernatant is colorless and transparent, and drying the residue at 80 ℃ to constant weight to obtain modified pine needles;

Putting 20g of modified pine needles into 200mL0.6mol/L phenylenediamine solution, stirring for 1 hour, depositing for 14 hours, then dripping sodium hydroxide solution under the stirring condition, controlling the pH value to be 8-9, standing and standing for 24 hours, and stirring for 5 minutes at intervals of 3 hours;

Example 5

taking 100g of crushed pine needles, and subjecting to supercritical CO₂200mL of 95% NaOH solution, washing the residue obtained after extracting the active ingredients of the pine needles for 16h with distilled water until the supernatant is colorless and transparent, and drying at 80 ℃ to constant weight to obtain modified pine needles;

20g of modified pine needles are put into 200mL0.8mol/L phenylenediamine solution, stirred for 1h and then deposited for 16h, then sodium hydroxide solution is dropped under the stirring condition, the pH value is controlled to be 8-9, the mixture is kept stand for 24h, and stirring is carried out for 5min at intervals of 3 h;

Detection example 1

in this example, the adsorption isotherm of the chloramphenicol adsorbent prepared in example 2 was measured. The method specifically comprises the following steps:

The chloramphenicol adsorbent prepared in example 2 was put into five flasks, 0.1g was put into each flask, 50ml of chloramphenicol aqueous solutions having concentrations of 100, 200, 300, 400, and 500mg/L were added, and the mixture was placed in a constant temperature oscillator at a certain temperature (293, 303, or 313K) and oscillated for about 8 hours to allow the adsorption to reach equilibrium. The absorbance was measured at the maximum absorption wavelength and converted to the equilibrium concentration, and the equilibrium adsorption amount (qe) of chloramphenicol to the resin was calculated according to the following formula:

q_e＝(C₀-C_e)V/W，

C₀Means CAP concentration (mg/L) in the solution before adsorption;

C_eMeans CAP concentration (mg/L) in the solution after adsorption equilibrium;

v denotes the volume of the adsorption solution (L);

w denotes the adsorbent weight (g).

the test results are shown in fig. 3.

as can be seen from FIG. 3, the adsorption amount gradually decreased with increasing temperature, indicating that the adsorption is an exothermic process and that the adsorption effect is the best at 293K.

The adsorption process is generally described by Langmuir and Freundlich isothermal equations. The Langmuir relationship is an ideal adsorption formula that represents the regularity that adsorbed molecules have no effect on each other on an isothermal and uniform surface, and that adsorption is equilibrium in the case of a monolayer. Its role in adsorption theory is similar to the ideal gas law in gas dynamic theory, and its equation can be expressed as follows:

wherein q is_mthe maximum adsorption capacity (mg/g), K, of the resin_L(L/mg) is a constant.

The Freundlich model represents the adsorption equilibrium with the heat of adsorption decreasing logarithmically with increasing coverage at isothermal temperature. The characteristic of the Freundlich equation is that it has no saturated adsorption value, and is widely used for physical adsorption, chemical adsorption and solution adsorption.

The equation is as follows:

lnq_e＝lnK_f+(1/n)lnC_e，

Wherein n, K_fis a constant.

The adsorption equilibrium data on the chloramphenicol adsorbent was fitted using Langmuir and Freundlich equations, with the fitting equations, relevant parameters and relevant coefficients shown in tables 1 and 2.

TABLE 1 Langmuir equation adsorption of Chloramphenicol by fitting resin

TABLE 2 Freundlich equation fitting of adsorption of Chloramphenicol by resin

It can be seen that the adsorption equilibrium data of the chloramphenicol adsorbent to chloramphenicol in an aqueous solution more conforms to a Freundlich equation model, the correlation coefficient is greater than 0.99, and the chloramphenicol adsorbent belongs to multilayer adsorption.

Detection example 2

In this example, the temperature curve of the adsorption kinetics of the chloramphenicol adsorbent prepared in example 3 was measured. The method specifically comprises the following steps:

0.1g of the chloramphenicol adsorbent obtained in example 3 was weighed into a 500ml Erlenmeyer flask, 250ml of a 500mg/L chloramphenicol aqueous solution was added, and the mixture was shaken at a constant temperature of 293K. Sampling every 10min for one hour, sampling every 30min, measuring the absorbance until the absorbance is basically stable, and calculating the adsorption quantity qt of the resin to the chloramphenicol at the time t according to the following formula:

q_t＝(C₀-C_t)V/W，

C_tAnd refers to the CAP concentration (mg/L) in the solution at time t.

The test results are shown in fig. 4.

As can be seen from fig. 4, as adsorption proceeds, the amount of CAP adsorbed on the adsorbent rapidly increases, and the adsorbent reaches adsorption equilibrium around 120 min.

Detection example 3

The example examined the effect of pH on adsorption, specifically:

50ml of a 500mg/L aqueous chloramphenicol solution was added to various Erlenmeyer flasks, and the pH of the solution was adjusted with 0.1mol/L NaOH or 0.1mol/L HCl. 0.1g of the chloramphenicol adsorbent obtained in example 2 was accurately weighed and added to the corresponding solution. The solution was shaken at constant temperature of 293K for 2 hours to determine the equilibrium adsorption amount. The influence curve of pH on adsorption was plotted with the initial solution pH as abscissa and the equilibrium adsorption amount of the adsorbent on chloramphenicol as ordinate, as shown in FIG. 5.

As can be seen from fig. 5, increasing the pH of the CAP aqueous solution and adding sodium hydroxide to the CAP aqueous solution rapidly decreases the amount of CAP adsorbed on the resin surface, so that the adsorption process is suitably performed in an acidic environment, and the pH is preferably 2 to 6.

detection example 4

The example performed the maximum adsorption test, specifically:

50ml of a 500mg/L chloramphenicol aqueous solution was added to each of different Erlenmeyer flasks, 0.1g each of the chloramphenicol adsorbents obtained in examples 1 to 4 was taken, and the solutions were added to the different Erlenmeyer flasks, and the flasks were shaken at a constant temperature of 293K to measure the maximum adsorption amounts, which were: 92mg g-1, 91.5mg g-1, 91.8mg g-1, 92.8mg g-1.

Detection example 5

In this example, the measurement of static desorption was carried out, specifically:

0.1g of the chloramphenicol adsorbent obtained in example 2 and 50ml of a 500mg/L aqueous chloramphenicol solution were placed in an Erlenmeyer flask, and the mixture was shaken under an acidic condition of 298K for 2 hours to calculate an equilibrium adsorption q_e. Separating the adsorbent from the residual liquid, washing the pine needles with 1ml of distilled water for 3-5 times, and then respectively adding various desorbing agents, such as: a static desorption effect comparison test was performed on 50ml of distilled water (No. 1), 50ml of a 1% hydrochloric acid solution (No. 2), 50ml of a 50% ethanol solution (No. 3), 50ml of a 75% hydrochloric acid (No. 4), 50ml of a 75% ethanol solution (No. 5), and a 1% hydrochloric acid mixed solution (No. 6). The mixture was shaken at 293K for 8h in a constant temperature shaker. And then measuring the solubility of the chloramphenicol solution in the desorbent, calculating the equilibrium desorption amount qe, and calculating the desorption percentage.

As shown in table 3 below.

Table 3 desorption test data

Test items	1	2	3	4	5	6
							mass W/g of adsorbent	0.1000	0.1016	0.1037	0.1007	0.1008	0.1003
absorbance/A	0.059	0.068	0.203	0.188	0.131	0.149
							C_e/mg.L^-1	31.68	38.47	140.5	129.1	86.07	99.67
q_e/mg.g^-1	15.84	18.94	67.74	64.10	42.12	49.69
							Percent desorption/%	17	22	73	70	46	56

As can be seen from table 3 above, the chloramphenicol adsorbent after adsorbing chloramphenicol had the best desorption effect in a 50% ethanol solution, reaching 73%.

Therefore, the chloramphenicol adsorbent provided by the application can be well desorbed after adsorbing chloramphenicol, and further can be recycled.

Comparative example 1

0.1g of the original pulverized pine needles were used, and 50ml of 500mg/L chloramphenicol aqueous solution was added to test the maximum adsorption amount according to the same experimental method.

The maximum adsorption capacity is as follows: 11.9mg g-1.

Comparative example 2

different from the example 2, only the modification reaction is carried out to prepare the modified pine needle.

0.1g of the above modified pine needles were used, and 50ml of 500mg/L chloramphenicol aqueous solution was added to test the maximum adsorption amount according to the same experimental method.

The maximum adsorption capacity is as follows: 48.1mg g-1.

From the comparison between the maximum adsorption capacity of the chloramphenicol adsorbents obtained in the embodiments 2 to 4 and the maximum adsorption capacity of the pine needles in the comparative examples 1 to 2, it can be seen that the chloramphenicol adsorbent provided by the embodiments of the present invention has high selectivity and adsorption performance for chloramphenicol.

The chloramphenicol adsorbent provided by the application is simple in synthesis method and low in cost; the chloramphenicol adsorbent has strong adsorption capacity, high adsorption selectivity on chloramphenicol, easy desorption and repeated cyclic utilization; the method for removing the chloramphenicol by using the chloramphenicol adsorbent is simple, efficient and easy to operate, and has no secondary pollution.

while particular embodiments of the present invention have been illustrated and described, it would be obvious that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. a preparation process of a chloramphenicol adsorbent is characterized by comprising the following steps:

2. The process of claim 1, wherein the step S1 is performed by pulverizing with a sieving range of less than 60 mesh.

3. The preparation process according to claim 1, wherein the temperature of the primary drying is 70 to 90 ℃.

4. The process according to claim 1, wherein the modifier solution has a concentration of 0.2 mol/L.

5. The process of claim 1 or 4, wherein the modifier comprises phenylenediamine.

6. The process of claim 1, wherein the extractant of the extraction process of step S2 includes supercritical carbon dioxide and an expansion liquid.

7. The process of claim 1, wherein the soaking time in step S2 is 12 h.

8. the process of claim 1, wherein the modifier solution of step S3 has a pH greater than 7.

9. The process according to claim 1, wherein the standing time in step S3 is 24 h.

10. The manufacturing process according to claim 1, wherein the temperature of the third drying treatment in step S4 is 80 ℃.